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Yu X, Guo J, Mao Y, Shan C, Tian F, Meng B, Wang Z, Zhang T, Kyaw AKK, Chen S, Sun X, Wang K, Chen R, Xing G. Enhancing the Performance of Perovskite Light-Emitting Diodes via Synergistic Effect of Defect Passivation and Dielectric Screening. NANO-MICRO LETTERS 2024; 16:205. [PMID: 38819522 PMCID: PMC11143140 DOI: 10.1007/s40820-024-01405-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 03/28/2024] [Indexed: 06/01/2024]
Abstract
Metal halide perovskites, particularly the quasi-two-dimensional perovskite subclass, have exhibited considerable potential for next-generation electroluminescent materials for lighting and display. Nevertheless, the presence of defects within these perovskites has a substantial influence on the emission efficiency and durability of the devices. In this study, we revealed a synergistic passivation mechanism on perovskite films by using a dual-functional compound of potassium bromide. The dual functional potassium bromide on the one hand can passivate the defects of halide vacancies with bromine anions and, on the other hand, can screen the charged defects at the grain boundaries with potassium cations. This approach effectively reduces the probability of carriers quenching resulting from charged defects capture and consequently enhances the radiative recombination efficiency of perovskite thin films, leading to a significant enhancement of photoluminescence quantum yield to near-unity values (95%). Meanwhile, the potassium bromide treatment promoted the growth of homogeneous and smooth film, facilitating the charge carrier injection in the devices. Consequently, the perovskite light-emitting diodes based on this strategy achieve a maximum external quantum efficiency of ~ 21% and maximum luminance of ~ 60,000 cd m-2. This work provides a deeper insight into the passivation mechanism of ionic compound additives in perovskite with the solution method.
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Affiliation(s)
- Xuanchi Yu
- Institute of Applied Physics and Materials Engineering, University of Macau, Avenida da Universidade, Taipa, Macao, 999078, People's Republic of China
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, 518055, People's Republic of China
| | - Jia Guo
- Institute of Applied Physics and Materials Engineering, University of Macau, Avenida da Universidade, Taipa, Macao, 999078, People's Republic of China.
| | - Yulin Mao
- Institute of Applied Physics and Materials Engineering, University of Macau, Avenida da Universidade, Taipa, Macao, 999078, People's Republic of China
| | - Chengwei Shan
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, 518055, People's Republic of China
| | - Fengshou Tian
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, 518055, People's Republic of China
| | - Bingheng Meng
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, 518055, People's Republic of China
| | - Zhaojin Wang
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, 518055, People's Republic of China
| | - Tianqi Zhang
- Institute of Applied Physics and Materials Engineering, University of Macau, Avenida da Universidade, Taipa, Macao, 999078, People's Republic of China
| | - Aung Ko Ko Kyaw
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, 518055, People's Republic of China
| | - Shuming Chen
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, 518055, People's Republic of China
| | - Xiaowei Sun
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, 518055, People's Republic of China
| | - Kai Wang
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, 518055, People's Republic of China
| | - Rui Chen
- Department of Electrical and Electronic Engineering, Southern University of Science and Technology, Shenzhen, 518055, People's Republic of China.
| | - Guichuan Xing
- Institute of Applied Physics and Materials Engineering, University of Macau, Avenida da Universidade, Taipa, Macao, 999078, People's Republic of China.
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2
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Wang B, Yao S, Hu W, Peng L, Shi T, Wang Y, Chen J, Liu X, Lin J. Rational control of the typical surface defects of hybrid perovskite using tetrahexylammonium iodide. Phys Chem Chem Phys 2024; 26:9488-9499. [PMID: 38450544 DOI: 10.1039/d3cp06081k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2024]
Abstract
There are numerous defects existing on the surface and grain boundary of perovskite, which adversely affect the performance and stability of perovskite solar cell devices. Systematic first-principles calculations show that the I vacancy (VI), Pb vacancy (VPb), Pb-I antisite (PbI), and I-Pb antisite (IPb) defects can significantly affect the electronic properties of the surface of formamidinium lead triiodide (FAPbI3); in particular the VPb, PbI and IPb surface defects can introduce defect energy levels in the band gap. Tetrahexylammonium iodide (THAI) that is strongly adsorbed on the (1 0 0) surface of FAPbI3 by forming Pb-I coordination bonds and I⋯H hydrogen bonds could eliminate or reduce the defect states near the band edge or in the band gap by transferring electrons between THAI and the surface of FAPbI3. In particular, the defect states introduced by VPb could be completely eliminated after the adsorption of THAI. This study shows an in-depth understanding of the influence of defects on the electronic properties of the surface of FAPbI3, as well as the passivation mechanism of organic salts on the surface defects of perovskite.
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Affiliation(s)
- Ben Wang
- Department of Physics, Shanghai University of Electric Power, Shanghai 200090, China.
| | - Shunwei Yao
- Department of Physics, Shanghai University of Electric Power, Shanghai 200090, China.
| | - Wenjing Hu
- Department of Physics, Shanghai University of Electric Power, Shanghai 200090, China.
| | - Lin Peng
- Department of Physics, Shanghai University of Electric Power, Shanghai 200090, China.
| | - Tingting Shi
- Department of Physics, Jinan University, Guangzhou 510632, China
| | - Yanan Wang
- Department of Physics, Shanghai University of Electric Power, Shanghai 200090, China.
| | - Jing Chen
- Department of Physics, Shanghai University of Electric Power, Shanghai 200090, China.
| | - Xiaolin Liu
- Department of Physics, Shanghai University of Electric Power, Shanghai 200090, China.
| | - Jia Lin
- Department of Physics, Shanghai University of Electric Power, Shanghai 200090, China.
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3
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Liu XY, Chen WK, Fang WH, Cui G. Nonadiabatic Dynamics Simulations for Photoinduced Processes in Molecules and Semiconductors: Methodologies and Applications. J Chem Theory Comput 2023. [PMID: 37984502 DOI: 10.1021/acs.jctc.3c00960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
Nonadiabatic dynamics (NAMD) simulations have become powerful tools for elucidating complicated photoinduced processes in various systems from molecules to semiconductor materials. In this review, we present an overview of our recent research on photophysics of molecular systems and periodic semiconductor materials with the aid of ab initio NAMD simulation methods implemented in the generalized trajectory surface-hopping (GTSH) package. Both theoretical backgrounds and applications of the developed NAMD methods are presented in detail. For molecular systems, the linear-response time-dependent density functional theory (LR-TDDFT) method is primarily used to model electronic structures in NAMD simulations owing to its balanced efficiency and accuracy. Moreover, the efficient algorithms for calculating nonadiabatic coupling terms (NACTs) and spin-orbit couplings (SOCs) have been coded into the package to increase the simulation efficiency. In combination with various analysis techniques, we can explore the mechanistic details of the photoinduced dynamics of a range of molecular systems, including charge separation and energy transfer processes in organic donor-acceptor structures, ultrafast intersystem crossing (ISC) processes in transition metal complexes (TMCs), and exciton dynamics in molecular aggregates. For semiconductor materials, we developed the NAMD methods for simulating the photoinduced carrier dynamics within the framework of the Kohn-Sham density functional theory (KS-DFT), in which SOC effects are explicitly accounted for using the two-component, noncollinear DFT method. Using this method, we have investigated the photoinduced carrier dynamics at the interface of a variety of van der Waals (vdW) heterojunctions, such as two-dimensional transition metal dichalcogenides (TMDs), carbon nanotubes (CNTs), and perovskites-related systems. Recently, we extended the LR-TDDFT-based NAMD method for semiconductor materials, allowing us to study the excitonic effects in the photoinduced energy transfer process. These results demonstrate that the NAMD simulations are powerful tools for exploring the photodynamics of molecular systems and semiconductor materials. In future studies, the NAMD simulation methods can be employed to elucidate experimental phenomena and reveal microscopic details as well as rationally design novel photofunctional materials with desired properties.
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Affiliation(s)
- Xiang-Yang Liu
- College of Chemistry and Material Science, Sichuan Normal University, Chengdu 610068, P. R. China
| | - Wen-Kai Chen
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China
| | - Wei-Hai Fang
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China
- Hefei National Laboratory, Hefei 230088, P. R. China
| | - Ganglong Cui
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China
- Hefei National Laboratory, Hefei 230088, P. R. China
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4
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Zhao B, Li Y, Chen X, Han Y, Wei S, Wu K, Zhang X. Engineering Carrier Dynamics in Halide Perovskites by Dynamical Lattice Distortion. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2300386. [PMID: 37807821 PMCID: PMC10667814 DOI: 10.1002/advs.202300386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 08/31/2023] [Indexed: 10/10/2023]
Abstract
The electronic structure of halide perovskites is central to their carrier dynamics, enabling the excellent optoelectronic performance. However, the experimentally resolved transient absorption spectra exhibit large discrepancies from the commonly computed electronic structure by density functional theory. Using pseudocubic CsPbI3 as a prototype example, here, it is unveiled with both ab initio molecular dynamics simulations and transmission electron microscopy that there exists pronounced dynamical lattice distortion in the form of disordered instantaneous octahedral tilting. Rigorous first-principles calculations reveal that the lattice distortion substantially alters the electronic band structure through renormalizing the band dispersions and the interband transition energies. Most notably, the electron and hole effective masses increase by 65% and 88%, respectively; the transition energy between the two highest valence bands decreases by about one half, agreeing remarkably well with supercontinuum transient-absorption measurements. This study further demonstrates how the resulting electronic structure modulates various aspects of the carrier dynamics such as carrier transport, hot-carrier relaxation, Auger recombination, and carrier multiplication in halide perovskites. The insights provide a pathway to engineer carrier transport and relaxation via lattice distortion, enabling the promise to achieve ultrahigh-efficiency photovoltaic devices.
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Affiliation(s)
- Bai‐Qing Zhao
- Beijing Computational Science Research CenterBeijing100193China
| | - Yulu Li
- State Key Laboratory of Molecular Reaction DynamicsDalian Institute of Chemical PhysicsChinese Academy of SciencesDalianLiaoning116023China
| | - Xuan‐Yan Chen
- Beijing Computational Science Research CenterBeijing100193China
| | - Yaoyao Han
- State Key Laboratory of Molecular Reaction DynamicsDalian Institute of Chemical PhysicsChinese Academy of SciencesDalianLiaoning116023China
- University of Chinese Academy of SciencesBeijing100049China
| | - Su‐Huai Wei
- Beijing Computational Science Research CenterBeijing100193China
| | - Kaifeng Wu
- State Key Laboratory of Molecular Reaction DynamicsDalian Institute of Chemical PhysicsChinese Academy of SciencesDalianLiaoning116023China
- University of Chinese Academy of SciencesBeijing100049China
| | - Xie Zhang
- Beijing Computational Science Research CenterBeijing100193China
- School of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi'an710072China
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5
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Mosquera-Lois I, Kavanagh SR, Klarbring J, Tolborg K, Walsh A. Imperfections are not 0 K: free energy of point defects in crystals. Chem Soc Rev 2023; 52:5812-5826. [PMID: 37565783 DOI: 10.1039/d3cs00432e] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
Defects determine many important properties and applications of materials, ranging from doping in semiconductors, to conductivity in mixed ionic-electronic conductors used in batteries, to active sites in catalysts. The theoretical description of defect formation in crystals has evolved substantially over the past century. Advances in supercomputing hardware, and the integration of new computational techniques such as machine learning, provide an opportunity to model longer length and time-scales than previously possible. In this Tutorial Review, we cover the description of free energies for defect formation at finite temperatures, including configurational (structural, electronic, spin) and vibrational terms. We discuss challenges in accounting for metastable defect configurations, progress such as machine learning force fields and thermodynamic integration to directly access entropic contributions, and bottlenecks in going beyond the dilute limit of defect formation. Such developments are necessary to support a new era of accurate defect predictions in computational materials chemistry.
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Affiliation(s)
- Irea Mosquera-Lois
- Thomas Young Centre & Department of Materials, Imperial College London, London SW7 2AZ, UK.
| | - Seán R Kavanagh
- Thomas Young Centre & Department of Materials, Imperial College London, London SW7 2AZ, UK.
- Thomas Young Centre & Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, UK
| | - Johan Klarbring
- Thomas Young Centre & Department of Materials, Imperial College London, London SW7 2AZ, UK.
- Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-581 83, Linköping, Sweden
| | - Kasper Tolborg
- Thomas Young Centre & Department of Materials, Imperial College London, London SW7 2AZ, UK.
- I-X, Imperial College London, London W12 0BZ, UK
| | - Aron Walsh
- Thomas Young Centre & Department of Materials, Imperial College London, London SW7 2AZ, UK.
- Department of Physics, Ewha Womans University, Seoul 03760, Korea
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6
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Goetz KP, Thome FTF, An Q, Hofstetter YJ, Schramm T, Yangui A, Kiligaridis A, Loeffler M, Taylor AD, Scheblykin IG, Vaynzof Y. Remarkable performance recovery in highly defective perovskite solar cells by photo-oxidation. JOURNAL OF MATERIALS CHEMISTRY. C 2023; 11:8007-8017. [PMID: 37362025 PMCID: PMC10286220 DOI: 10.1039/d2tc05077c] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 01/25/2023] [Indexed: 06/28/2023]
Abstract
Exposure to environmental factors is generally expected to cause degradation in perovskite films and solar cells. Herein, we show that films with certain defect profiles can display the opposite effect, healing upon exposure to oxygen under illumination. We tune the iodine content of methylammonium lead triiodide perovskite from understoichiometric to overstoichiometric and expose them to oxygen and light prior to the addition of the top layers of the device, thereby examining the defect dependence of their photooxidative response in the absence of storage-related chemical processes. The contrast between the photovoltaic properties of the cells with different defects is stark. Understoichiometric samples indeed degrade, demonstrating performance at 33% of their untreated counterparts, while stoichiometric samples maintain their performance levels. Surprisingly, overstoichiometric samples, which show low current density and strong reverse hysteresis when untreated, heal to maximum performance levels (the same as untreated, stoichiometric samples) upon the photooxidative treatment. A similar, albeit smaller-scale, effect is observed for triple cation and methylammonium-free compositions, demonstrating the general application of this treatment to state-of-the-art compositions. We examine the reasons behind this response by a suite of characterization techniques, finding that the performance changes coincide with microstructural decay at the crystal surface, reorientation of the bulk crystal structure for the understoichiometric cells, and a decrease in the iodine-to-lead ratio of all films. These results indicate that defect engineering is a powerful tool to manipulate the stability of perovskite solar cells.
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Affiliation(s)
- Katelyn P Goetz
- Chair for Emerging Electronic Technologies, Technical University of Dresden Nöthnitzer Str. 61 01187 Dresden Germany
| | - Fabian T F Thome
- Kirchhoff Institute for Physics, University of Heidelberg Heidelberg Germany
| | - Qingzhi An
- Chair for Emerging Electronic Technologies, Technical University of Dresden Nöthnitzer Str. 61 01187 Dresden Germany
| | - Yvonne J Hofstetter
- Chair for Emerging Electronic Technologies, Technical University of Dresden Nöthnitzer Str. 61 01187 Dresden Germany
- Leibniz-Institute for Solid State and Materials Research Dresden Helmholtzstraße 20 01069 Dresden Germany
| | - Tim Schramm
- Chair for Emerging Electronic Technologies, Technical University of Dresden Nöthnitzer Str. 61 01187 Dresden Germany
- Leibniz-Institute for Solid State and Materials Research Dresden Helmholtzstraße 20 01069 Dresden Germany
| | - Aymen Yangui
- Chemical Physics and NanoLund, Lund University Lund Sweden
| | | | - Markus Loeffler
- Dresden Center for Nanoanalysis, Technical University of Dresden Dresden Germany
| | - Alexander D Taylor
- Chair for Emerging Electronic Technologies, Technical University of Dresden Nöthnitzer Str. 61 01187 Dresden Germany
| | | | - Yana Vaynzof
- Chair for Emerging Electronic Technologies, Technical University of Dresden Nöthnitzer Str. 61 01187 Dresden Germany
- Leibniz-Institute for Solid State and Materials Research Dresden Helmholtzstraße 20 01069 Dresden Germany
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7
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Zuri S, Shapiro A, Kronik L, Lifshitz E. Uncovering Multiple Intrinsic Chiral Phases in (PEA) 2PbI 4 Halide Perovskites. J Phys Chem Lett 2023:4901-4907. [PMID: 37200134 DOI: 10.1021/acs.jpclett.3c00685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Two-dimensional (2D) halide perovskites offer a unique platform for investigating the ground state of materials possessing significant anharmonicity. In contrast to three-dimensional perovskites, their 2D counterparts offer substantially fewer degrees of freedom, resulting in multiple well-defined crystal structures. In this work, we thoroughly investigate the anharmonic ground state of the benchmark (PEA)2PbI4 compound, using complementary information from low-temperature X-ray diffraction (XRD) and photoluminescence spectroscopy, supported by density functional theory calculations. We extrapolate four crystallographic configurations from low-temperature XRD. These configurations imply that the ground state has an intrinsic disorder stemming from two coexisting chiral sublattices, each with a bioriented organic spacer molecule. We further show evidence that these chiral structures form unevenly populated ground states, portraying uneven anharmonicity, where the state population may be tuned by surface effects. Our results uncover a disordered ground state that may induce intrinsic grain boundaries, which cannot be ignored in practical applications.
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Affiliation(s)
- Shahar Zuri
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute, Helen Diller Quantum Information Center and the Grand Technion Energy Program, Technion, Haifa 3200003, Israel
| | - Arthur Shapiro
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute, Helen Diller Quantum Information Center and the Grand Technion Energy Program, Technion, Haifa 3200003, Israel
| | - Leeor Kronik
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovoth 76100, Israel
| | - Efrat Lifshitz
- Schulich Faculty of Chemistry, Solid State Institute, Russell Berrie Nanotechnology Institute, Helen Diller Quantum Information Center and the Grand Technion Energy Program, Technion, Haifa 3200003, Israel
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8
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Mahal E, Mandal SC, Roy D, Pathak B. Energy level alignments between organic and inorganic layers in 2D layered perovskites: conjugation vs. substituent. NANOSCALE 2023; 15:7962-7970. [PMID: 37067050 DOI: 10.1039/d3nr01105d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
2D layered hybrid perovskites have attracted huge attention due to their interesting optoelectronic properties and chemical flexibility. Depending upon their electronic structures and properties, these materials can be utilised in various optoelectronic devices like photovoltaics, LEDs and so on. In this context, study of the excited energy levels of the organic spacers can help us to align the excited energy levels of the organic unit with the excitonic level of the inorganic unit according to the requirement of a particular optoelectronic device. We have explored the role of 3-phenyl-2-propenammonium on the electronic structure of a perovskite containing this cation as a spacer. Our results clearly demonstrate the active participation of conjugated ammonium spacers in the electronic structure of a perovskite. Also, we have considered a variety of amines to identify the best alignment with common inorganic units and studied the role of substituents and conjugation on the energy level alignment. Placing the triplet excited level of an organic spacer below the lowest excitonic level of the inorganic unit can induce energy transfer from the inorganic to organic unit, finally resulting in phosphorescence emission. We have shown that the triplet energy level of 3-anthracene-2-propeneamine/3-pyrene-2-propeneamine can be tuned in such a way that there can be an excitonic energy transfer from the Pb2I7/PbI4 inorganic unit-based perovskites. Therefore, perovskite material with such combinations of organic spacer cations will be very useful for light emission applications.
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Affiliation(s)
- Eti Mahal
- Department of Chemistry, Indian Institute of Technology Indore, Indore 453552, India.
| | - Shyama Charan Mandal
- Department of Chemistry, Indian Institute of Technology Indore, Indore 453552, India.
| | - Diptendu Roy
- Department of Chemistry, Indian Institute of Technology Indore, Indore 453552, India.
| | - Biswarup Pathak
- Department of Chemistry, Indian Institute of Technology Indore, Indore 453552, India.
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9
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McArthur J, Filip MR, Qiu DY. Minimal Molecular Building Blocks for Screening in Quasi-Two-Dimensional Organic-Inorganic Lead Halide Perovskites. NANO LETTERS 2023; 23:3796-3802. [PMID: 37092908 DOI: 10.1021/acs.nanolett.3c00082] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Layered hybrid organic-inorganic lead halide perovskites have intriguing optoelectronic properties, but some of the most interesting perovskite systems, such as defective, disordered, or mixed perovskites, require multiple unit cells to describe and are not accessible within state-of-the-art ab initio theoretical approaches for computing excited states. The principal bottleneck is the calculation of the dielectric matrix, which scales formally as O(N4). We develop here a fully ab initio approximation for the dielectric matrix, known as IPSA-2C, in which we separate the polarizability of the organic/inorganic layers into minimal building blocks, thus circumventing the undesirable power-law scaling. The IPSA-2C method reproduces the quasi-particle band structures and absorption spectra for a series of Ruddlesden-Popper perovskites to high accuracy, by including critical nonlocal effects neglected in simpler models, and sheds light on the complicated interplay of screening between the organic and inorganic sublattices.
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Affiliation(s)
- Jack McArthur
- Department of Physics, Yale University, New Haven, Connecticut 06520, United States
- Department of Physics, University of California at Berkeley, Berkeley, California 94720, United States
| | - Marina R Filip
- Department of Physics, University of Oxford, Clarendon Laboratory, Oxford OX1 3PU, United Kingdom
| | - Diana Y Qiu
- Department of Mechanical Engineering and Materials Science, Yale University, New Haven, Connecticut 06520, United States
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10
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Kerner RA, Cohen AV, Xu Z, Kirmani AR, Park SY, Harvey SP, Murphy JP, Cawthorn RC, Giebink NC, Luther JM, Zhu K, Berry JJ, Kronik L, Rand BP. Electrochemical Doping of Halide Perovskites by Noble Metal Interstitial Cations. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023:e2302206. [PMID: 37052234 DOI: 10.1002/adma.202302206] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 03/29/2023] [Indexed: 06/04/2023]
Abstract
Metal halide perovskites are an attractive class of semiconductors, but it has proven difficult to control their electronic doping by conventional strategies due to screening and compensation by mobile ions or ionic defects. Noble-metal interstitials represent an under-studied class of extrinsic defects that plausibly influence many perovskite-based devices. In this work, doping of metal halide perovskites is studied by electrochemically formed Au+ interstitial ions, combining experimental data on devices with a computational analysis of Au+ interstitial defects based on density functional theory (DFT). Analysis suggests that Au+ cations can be easily formed and migrate through the perovskite bulk via the same sites as iodine interstitials (Ii + ). However, whereas Ii + compensates n-type doping by electron capture, the noble-metal interstitials act as quasi-stable n-dopants. Experimentally, voltage-dependent, dynamic doping by current density-time (J-t), electrochemical impedance, and photoluminescence measurements are characterized. These results provide deeper insight into the potential beneficial and detrimental impacts of metal electrode reactions on long-term performance of perovskite photovoltaic and light-emitting diodes, as well as offer an alternative doping explanation for the valence switching mechanism of halide-perovskite-based neuromorphic and memristive devices.
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Affiliation(s)
- Ross A Kerner
- National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Ayala V Cohen
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovoth, 76100, Israel
| | - Zhaojian Xu
- Department of Electrical Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Ahmad R Kirmani
- National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - So Yeon Park
- National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Steven P Harvey
- National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - John P Murphy
- Department of Electrical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Robert C Cawthorn
- Department of Electrical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Noel C Giebink
- Department of Electrical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Joseph M Luther
- National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Kai Zhu
- National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Joseph J Berry
- National Renewable Energy Laboratory, Golden, CO, 80401, USA
- Department of Physics, University of Colorado Boulder, Boulder, CO, 80309, USA
- Renewable and Sustainable Energy Institute, University of Colorado Boulder, Boulder, CO, 80309, USA
| | - Leeor Kronik
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovoth, 76100, Israel
| | - Barry P Rand
- Department of Electrical Engineering, Princeton University, Princeton, NJ, 08544, USA
- Andlinger Center for Energy and the Environment, Princeton University, Princeton, NJ, 08544, USA
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11
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Chatratin I, Dou B, Wei SH, Janotti A. Doping Limits of Phosphorus, Arsenic, and Antimony in CdTe. J Phys Chem Lett 2023; 14:273-278. [PMID: 36595563 DOI: 10.1021/acs.jpclett.2c03233] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Low p-type doping is a limiting factor to increase CdTe thin-film solar-cell efficiency toward the theoretical Shockley-Queisser limit of 33%. Previous calculations predict relatively high ionization energies for group-V acceptors (P, As, and Sb), and they are plagued by self-compensation, forming AX centers, severely limiting hole concentration. However, recent experiments on CdTe single crystals indicate a much more favorable scenario, where P, As, and Sb behave as shallow acceptors. Using hybrid functional calculations, we solve this puzzle by showing that the ionization energies significantly decrease with the supercell size. When including the effects of spin-orbit coupling and extrapolating the results to the dilute limit, we find these impurities behave as hydrogenic-like shallow acceptors, and AX centers are unstable and do not limit p-type doping. We address the differences between our results and previous theoretical predictions and show that our ionization energies predict hole concentrations that agree with recent temperature-dependent Hall measurements.
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Affiliation(s)
- Intuon Chatratin
- Department of Materials Science & Engineering, University of Delaware, Newark, Delaware19716, United States
| | - Baoying Dou
- Beijing Computational Science Research Center, Beijing100193, China
| | - Su-Huai Wei
- Beijing Computational Science Research Center, Beijing100193, China
| | - Anderson Janotti
- Department of Materials Science & Engineering, University of Delaware, Newark, Delaware19716, United States
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12
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Kahmann S, Meggiolaro D, Gregori L, Tekelenburg EK, Pitaro M, Stranks SD, De Angelis F, Loi MA. The Origin of Broad Emission in ⟨100⟩ Two-Dimensional Perovskites: Extrinsic vs Intrinsic Processes. ACS ENERGY LETTERS 2022; 7:4232-4241. [PMID: 36531144 PMCID: PMC9745793 DOI: 10.1021/acsenergylett.2c02123] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 10/28/2022] [Indexed: 06/15/2023]
Abstract
2D metal halide perovskites can show narrow and broad emission bands (BEs), and the latter's origin is hotly debated. A widespread opinion assigns BEs to the recombination of intrinsic self-trapped excitons (STEs), whereas recent studies indicate they can have an extrinsic defect-related origin. Here, we carry out a combined experimental-computational study into the microscopic origin of BEs for a series of prototypical phenylethylammonium-based 2D perovskites, comprising different metals (Pb, Sn) and halides (I, Br, Cl). Photoluminescence spectroscopy reveals that all of the compounds exhibit BEs. Where not observable at room temperature, the BE signature emerges upon cooling. By means of DFT calculations, we demonstrate that emission from halide vacancies is compatible with the experimentally observed features. Emission from STEs may only contribute to the BE in the wide-band-gap Br- and Cl-based compounds. Our work paves the way toward a complete understanding of broad emission bands in halide perovskites that will facilitate the fabrication of efficient narrow and white light emitting devices.
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Affiliation(s)
- Simon Kahmann
- Photophysics
and OptoElectronics Group, Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747
AG Groningen, The Netherlands
- Cavendish
Laboratory, University of Cambridge, JJ Thomson Avenue CB3 0HE Cambridge, U.K.
| | - Daniele Meggiolaro
- Computational
Laboratory for Hybrid/Organic Photovoltaics (CLHYO), Istituto CNR di Scienze e Tecnologie Chimiche (SCITEC−CNR), Via Elce di Sotto 8, 06123 Perugia, Italy
| | - Luca Gregori
- Department
of Chemistry, Biology and Biotechnology, University of Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy
| | - Eelco K. Tekelenburg
- Photophysics
and OptoElectronics Group, Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747
AG Groningen, The Netherlands
| | - Matteo Pitaro
- Photophysics
and OptoElectronics Group, Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747
AG Groningen, The Netherlands
| | - Samuel D. Stranks
- Cavendish
Laboratory, University of Cambridge, JJ Thomson Avenue CB3 0HE Cambridge, U.K.
- Department
of Chemical Engineering and Biotechnology, University of Cambridge, Philippa Fawcett Drive CB3 0AS Cambridge, U.K.
| | - Filippo De Angelis
- Computational
Laboratory for Hybrid/Organic Photovoltaics (CLHYO), Istituto CNR di Scienze e Tecnologie Chimiche (SCITEC−CNR), Via Elce di Sotto 8, 06123 Perugia, Italy
- Department
of Chemistry, Biology and Biotechnology, University of Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy
- Department
of Natural Sciences & Mathematics, College of Sciences & Human
Studies, Prince Mohammad Bin Fahd University, Dhahran 34754, Saudi Arabia
| | - Maria A. Loi
- Photophysics
and OptoElectronics Group, Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747
AG Groningen, The Netherlands
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13
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Guan X, Lei Z, Yu X, Lin CH, Huang JK, Huang CY, Hu L, Li F, Vinu A, Yi J, Wu T. Low-Dimensional Metal-Halide Perovskites as High-Performance Materials for Memory Applications. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2203311. [PMID: 35989093 DOI: 10.1002/smll.202203311] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 07/05/2022] [Indexed: 06/15/2023]
Abstract
Metal-halide perovskites have drawn profuse attention during the past decade, owing to their excellent electrical and optical properties, facile synthesis, efficient energy conversion, and so on. Meanwhile, the development of information storage technologies and digital communications has fueled the demand for novel semiconductor materials. Low-dimensional perovskites have offered a new force to propel the developments of the memory field due to the excellent physical and electrical properties associated with the reduced dimensionality. In this review, the mechanisms, properties, as well as stability and performance of low-dimensional perovskite memories, involving both molecular-level perovskites and structure-level nanostructures, are comprehensively reviewed. The property-performance correlation is discussed in-depth, aiming to present effective strategies for designing memory devices based on this new class of high-performance materials. Finally, the existing challenges and future opportunities are presented.
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Affiliation(s)
- Xinwei Guan
- School of Materials Science and Engineering, University of New South Wales (UNSW), Sydney, New South Wales, 2052, Australia
- Global Innovative Centre for Advanced Nanomaterials, School of Engineering, The University of Newcastle, Callaghan, New South Wales, 2308, Australia
| | - Zhihao Lei
- Global Innovative Centre for Advanced Nanomaterials, School of Engineering, The University of Newcastle, Callaghan, New South Wales, 2308, Australia
| | - Xuechao Yu
- Key Laboratory of Multifunctional Nanomaterials and Smart Systems, Suzhou Institute of Nanotech and Nano-bionics, Chinese Academy of Science, 398 Ruoshui Road, Suzhou, 215123, China
| | - Chun-Ho Lin
- School of Materials Science and Engineering, University of New South Wales (UNSW), Sydney, New South Wales, 2052, Australia
| | - Jing-Kai Huang
- School of Materials Science and Engineering, University of New South Wales (UNSW), Sydney, New South Wales, 2052, Australia
| | - Chien-Yu Huang
- School of Materials Science and Engineering, University of New South Wales (UNSW), Sydney, New South Wales, 2052, Australia
| | - Long Hu
- School of Materials Science and Engineering, University of New South Wales (UNSW), Sydney, New South Wales, 2052, Australia
| | - Feng Li
- School of Physics, Nano Institute, ACMM, The University of Sydney, Sydney, New South Wales, 2006, Australia
| | - Ajayan Vinu
- Global Innovative Centre for Advanced Nanomaterials, School of Engineering, The University of Newcastle, Callaghan, New South Wales, 2308, Australia
| | - Jiabao Yi
- Global Innovative Centre for Advanced Nanomaterials, School of Engineering, The University of Newcastle, Callaghan, New South Wales, 2308, Australia
| | - Tom Wu
- School of Materials Science and Engineering, University of New South Wales (UNSW), Sydney, New South Wales, 2052, Australia
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14
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Bao C, Gao F. Physics of defects in metal halide perovskites. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2022; 85:096501. [PMID: 35763940 DOI: 10.1088/1361-6633/ac7c7a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2021] [Accepted: 06/28/2022] [Indexed: 06/15/2023]
Abstract
Metal halide perovskites are widely used in optoelectronic devices, including solar cells, photodetectors, and light-emitting diodes. Defects in this class of low-temperature solution-processed semiconductors play significant roles in the optoelectronic properties and performance of devices based on these semiconductors. Investigating the defect properties provides not only insight into the origin of the outstanding performance of perovskite optoelectronic devices but also guidance for further improvement of performance. Defects in perovskites have been intensely studied. Here, we review the progress in defect-related physics and techniques for perovskites. We survey the theoretical and computational results of the origin and properties of defects in perovskites. The underlying mechanisms, functions, advantages, and limitations of trap state characterization techniques are discussed. We introduce the effect of defects on the performance of perovskite optoelectronic devices, followed by a discussion of the mechanism of defect treatment. Finally, we summarize and present key challenges and opportunities of defects and their role in the further development of perovskite optoelectronic devices.
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Affiliation(s)
- Chunxiong Bao
- Department of Physics, Chemistry, and Biology, Linköping University, Sweden
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing, 210093, People's Republic of China
| | - Feng Gao
- Department of Physics, Chemistry, and Biology, Linköping University, Sweden
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15
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Wang J, Yin WJ. Revisiting the Iodine Vacancy Surface Defects to Rationalize Passivation Strategies in Perovskite Solar Cells. J Phys Chem Lett 2022; 13:6694-6700. [PMID: 35848571 DOI: 10.1021/acs.jpclett.2c01815] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Current knowledge on the nature of surface iodine vacancies (VI), which are important for the photovoltaic performance and stability of perovskite solar cells, is debatable. We investigated VI on a stable MAI-terminated CH3NH3PbI3 (MAPbI3) surface. First-principles calculations indicated the sensitivity of the atomic structure of surface VI to the charge states and locations on the surface layer. VI in the outermost layer are benign; however, those near the surface can be detrimental. Illumination can promote the diffusion of VI from the outermost layer into the bulk, making them detrimental. There are two mechanisms for the surface passivation of VI: (i) passivation in the second layer to eliminate deep-state VI and (ii) passivation in the outermost layer to inhibit VI diffusion upon illumination (working condition of solar cells). This work rationalizes contradictory reports on the surface properties of halide perovskites and proposes insights into their surface passivation to fabricate high-performing solar cells.
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Affiliation(s)
- Jing Wang
- College of Energy, Soochow Institute for Energy and Materials InnovationS (SIEMIS), and Jiangsu Provincial Key Laboratory for Advanced Carbon Materials and Wearable Energy Technologies, Soochow University, Suzhou 215006, China
| | - Wan-Jian Yin
- College of Energy, Soochow Institute for Energy and Materials InnovationS (SIEMIS), and Jiangsu Provincial Key Laboratory for Advanced Carbon Materials and Wearable Energy Technologies, Soochow University, Suzhou 215006, China
- Light Industry Institute of Electrochemical Power Sources, Soochow University, Suzhou 215006, Jiangsu, China
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16
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Ning J, Zheng L, Lei W, Wang S, Xi J, Yang J. Temperature-dependence of the band gap in the all-inorganic perovskite CsPbI 3 from room to high temperatures. Phys Chem Chem Phys 2022; 24:16003-16010. [PMID: 35730744 DOI: 10.1039/d2cp00940d] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Understanding the micro-mechanism of the temperature dependence of the band gap in all-inorganic perovskites is of great significance for their optoelectronic and photovoltaic applications in various temperature environments. Herein, based on the recently developed electron-phonon renormalization method, the temperature-dependent band gaps of the optoelectronic perovskite CsPbI3 are studied from 300 K to 750 K (including orthorhombic, tetragonal, and cubic phases). It is found that the temperature-induced structural fluctuation makes the structure of perovskites deviate from the 0 K one, and the corresponding renormalized band gap differs from that at 0 K, especially for the high-temperature cubic phase (e.g., ΔEg is ∼177 meV at 600 K). However, within the temperature range of each CsPbI3 phase, the band gap Eg is enlarged slightly with the increase of temperature (e.g., ΔEg is ∼26 meV from 600 K to 750 K for the cubic phase), showing the insensitivity of the structural fluctuation effect to the temperature change. The reason is that the chemical characters of band edges are determined by PbI3-, and due to the strong correlation between Pb and I, the Pb-I bond lengths and Pb-I-Pb bond angles are almost unchanged as the temperature increases. Our work provides a fundamental understanding of the temperature-dependent band gaps in all-inorganic perovskites and shed light on the commercialization of perovskites.
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Affiliation(s)
- Jinyan Ning
- Materials Genome Institute, Shanghai University, Shanghai 200444, China.
| | - Liangliang Zheng
- Materials Genome Institute, Shanghai University, Shanghai 200444, China.
| | - Wenxin Lei
- Materials Genome Institute, Shanghai University, Shanghai 200444, China.
| | - Shenghao Wang
- Materials Genome Institute, Shanghai University, Shanghai 200444, China.
| | - Jinyang Xi
- Materials Genome Institute, Shanghai University, Shanghai 200444, China. .,Zhejiang Laboratory, Hangzhou, Zhejiang 311100, China
| | - Jiong Yang
- Materials Genome Institute, Shanghai University, Shanghai 200444, China. .,Zhejiang Laboratory, Hangzhou, Zhejiang 311100, China
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17
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Ri CH, Han HU, Kim YS, Jong UG, Kye YH, Yu CJ. Enhancing the Photocatalytic Hydrogen Evolution Performance of the CsPbI 3/MoS 2 Heterostructure with Interfacial Defect Engineering. J Phys Chem Lett 2022; 13:4007-4014. [PMID: 35485717 DOI: 10.1021/acs.jpclett.2c00851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Developing highly efficient photocatalysts for the hydrogen evolution reaction (HER) by solar-driven water splitting is a great challenge. Here, we study the atomistic origin of interface properties and the HER performance of all-inorganic iodide perovskite β-CsPbI3/2H-MoS2 heterostructures with interfacial vacancy defects using first-principles calculations. Both CsI/MoS2 and PbI2/MoS2 heterostructures have strong binding and dipole moment, which are enhanced by interfacial iodine vacancies (VI). Because of the nature of type II heterojunctions, photogenerated electrons on the CsPbI3 side are promptly transferred to the MoS2 side where HER occurs, and sulfur vacancies (VS) spoil this process, acting as surface traps. The formation energies of various defects are calculated by applying atomistic thermodynamics, identifying the growth conditions for promoting VI and suppressing VS formation. The HER performance is enhanced by forming interfaces with lower ΔGH values for hydrogen adsorption on the MoS2 side, suggesting PbI2/MoS2 with VI to be the most promising photocatalyst.
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Affiliation(s)
- Chol-Hyok Ri
- Chair of Computational Materials Design, Faculty of Materials Science, Kim Il Sung University, Ryongnam-Dong, Taesong District, Pyongyang, P.O. Box 76, 497335 Democratic People's Republic of Korea
| | - Hyon-U Han
- Chair of Computational Materials Design, Faculty of Materials Science, Kim Il Sung University, Ryongnam-Dong, Taesong District, Pyongyang, P.O. Box 76, 497335 Democratic People's Republic of Korea
| | - Yun-Sim Kim
- Chair of Computational Materials Design, Faculty of Materials Science, Kim Il Sung University, Ryongnam-Dong, Taesong District, Pyongyang, P.O. Box 76, 497335 Democratic People's Republic of Korea
| | - Un-Gi Jong
- Chair of Computational Materials Design, Faculty of Materials Science, Kim Il Sung University, Ryongnam-Dong, Taesong District, Pyongyang, P.O. Box 76, 497335 Democratic People's Republic of Korea
| | - Yun-Hyok Kye
- Chair of Computational Materials Design, Faculty of Materials Science, Kim Il Sung University, Ryongnam-Dong, Taesong District, Pyongyang, P.O. Box 76, 497335 Democratic People's Republic of Korea
| | - Chol-Jun Yu
- Chair of Computational Materials Design, Faculty of Materials Science, Kim Il Sung University, Ryongnam-Dong, Taesong District, Pyongyang, P.O. Box 76, 497335 Democratic People's Republic of Korea
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18
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Yuan Y, Yan G, Hong R, Liang Z, Kirchartz T. Quantifying Efficiency Limitations in All-Inorganic Halide Perovskite Solar Cells. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2108132. [PMID: 35014106 DOI: 10.1002/adma.202108132] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 12/22/2021] [Indexed: 06/14/2023]
Abstract
While halide perovskites have excellent optoelectronic properties, their poor stability is a major obstacle toward commercialization. There is a strong interest to move away from organic A-site cations such as methylammonium and formamidinium toward Cs with the aim of improving thermal stability of the perovskite layers. While the optoelectronic properties and the device performance of Cs-based all-inorganic lead-halide perovskites are very good, they are still trailing behind those of perovskites that use organic cations. Here, the state-of-the-art of all-inorganic perovskites for photovoltaic applications is reviewed by performing detailed meta-analyses of key performance parameters on the cell and material level. Key material properties such as carrier mobilities, external photoluminescence quantum efficiency, and photoluminescence lifetime are discussed and what is known about defect tolerance in all-inorganic is compared relative to hybrid (organic-inorganic) perovskites. Subsequently, a unified approach is adopted for analyzing performance losses in perovskite solar cells based on breaking down the losses into several figures of merit representing recombination losses, resistive losses, and optical losses. Based on this detailed loss analysis, guidelines are eventually developed for future performance improvement of all-inorganic perovskite solar cells.
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Affiliation(s)
- Ye Yuan
- Institute for Solar Energy Systems, Guangdong Provincial Key Laboratory of Photovoltaic Technology, School of Physics, Sun Yat-sen University, Guangzhou, 510006, P. R. China
- IEK5-Photovoltaik, Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Genghua Yan
- Institute for Solar Energy Systems, Guangdong Provincial Key Laboratory of Photovoltaic Technology, School of Physics, Sun Yat-sen University, Guangzhou, 510006, P. R. China
- IEK5-Photovoltaik, Forschungszentrum Jülich, 52425, Jülich, Germany
| | - Ruijiang Hong
- Institute for Solar Energy Systems, Guangdong Provincial Key Laboratory of Photovoltaic Technology, School of Physics, Sun Yat-sen University, Guangzhou, 510006, P. R. China
| | - Zongcun Liang
- Institute for Solar Energy Systems, Guangdong Provincial Key Laboratory of Photovoltaic Technology, School of Physics, Sun Yat-sen University, Guangzhou, 510006, P. R. China
| | - Thomas Kirchartz
- IEK5-Photovoltaik, Forschungszentrum Jülich, 52425, Jülich, Germany
- Faculty of Engineering and CENIDE, University of Duisburg-Essen, Carl-Benz-Str. 199, 47057, Duisburg, Germany
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19
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Du X, Liu Y, Pan W, Pang J, Zhu J, Zhao S, Chen C, Yu Y, Xiao Z, Niu G, Tang J. Chemical Potential Diagram Guided Rational Tuning of Electrical Properties: A Case Study of CsPbBr 3 for X-ray Detection. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2110252. [PMID: 35165950 DOI: 10.1002/adma.202110252] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 01/30/2022] [Indexed: 06/14/2023]
Abstract
Controlling the carrier polarity and concentration underlies most electronic and optoelectronic devices. However, for the intensively studied lead halide perovskites, the doping tunability is inefficient. In this work, taking CsPbBr3 as an example, it is revealed that the coexistence of metallic Pb or CsBr3 /Br2 , rather than the precursor ratio, can provide Pb-rich/Br-poor or Br-rich/Pb-poor chemical conditions, enabling the tunability of electrical properties from weak n-type, intrinsic, to moderate p-type. Experimentally, under Br2 -exposure treatment, a shift of the Fermi level as large as 1.00 eV is achieved, which is one of the highest value among all kinds of doping methods. The X-ray detector based on the intrinsic CsPbBr3 exhibits excellent performance, with a negligible dark-current drift of 7.1 × 10-4 nA cm-1 s-1 V-1 , a low detection limit of 103.6 nGyair s-1 , and a high sensitivity of 9085 μC Gyair -1 cm-2 . This work provides a critical understanding and guidance for tuning the electrical properties of lead halide perovskites, which establishes good foundations for achieving intrinsic perovskite semiconductors and also constructing potential homojunction devices.
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Affiliation(s)
- Xinyuan Du
- Wuhan National Laboratory for Optoelectronics & School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Yingmeng Liu
- Wuhan National Laboratory for Optoelectronics & School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Weicheng Pan
- Wuhan National Laboratory for Optoelectronics & School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Jincong Pang
- Wuhan National Laboratory for Optoelectronics & School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Jinsong Zhu
- Wuhan National Laboratory for Optoelectronics & School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Shan Zhao
- Wuhan National Laboratory for Optoelectronics & School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Chao Chen
- Wuhan National Laboratory for Optoelectronics & School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
- Optics Valley Laboratory, Hubei, 430074, China
| | - Yu Yu
- Wuhan National Laboratory for Optoelectronics & School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
- Optics Valley Laboratory, Hubei, 430074, China
| | - Zewen Xiao
- Wuhan National Laboratory for Optoelectronics & School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
- Optics Valley Laboratory, Hubei, 430074, China
| | - Guangda Niu
- Wuhan National Laboratory for Optoelectronics & School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
- Optics Valley Laboratory, Hubei, 430074, China
- Research Institute of Huazhong University of Science and Technology in Shenzhen, Shenzhen, 518000, China
| | - Jiang Tang
- Wuhan National Laboratory for Optoelectronics & School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, China
- Optics Valley Laboratory, Hubei, 430074, China
- Research Institute of Huazhong University of Science and Technology in Shenzhen, Shenzhen, 518000, China
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20
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Zhang X, Wei SH. Origin of Efficiency Enhancement by Lattice Expansion in Hybrid-Perovskite Solar Cells. PHYSICAL REVIEW LETTERS 2022; 128:136401. [PMID: 35426707 DOI: 10.1103/physrevlett.128.136401] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 03/07/2022] [Indexed: 06/14/2023]
Abstract
It has been experimentally observed that light-induced lattice expansion could enhance the solar conversion efficiency in hybrid perovskites, but the origin remains elusive. By performing rigorous first-principles calculations for a prototypical hybrid-perovskite FAPbI_{3} (FA: formamidinium), we show that 1% lattice expansion could already reduce the nonradiative capture coefficient by one order of magnitude. Unexpectedly, the suppressed nonradiative capture is not caused by changes in the band gap or defect transition level due to lattice expansion, but originates from enhanced defect relaxations associated with charge-state transitions in the expanded lattice. These insights not only provide a rationale for the efficiency enhancement by lattice expansion in hybrid perovskites, but also offer a general approach to the manipulation of nonradiative capture via strain engineering in a wide spectrum of optoelectronic materials.
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Affiliation(s)
- Xie Zhang
- Beijing Computational Science Research Center, Beijing 100193, China
| | - Su-Huai Wei
- Beijing Computational Science Research Center, Beijing 100193, China
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21
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Xie BB, Jia PK, Wang KX, Chen WK, Liu XY, Cui G. Generalized Ab Initio Nonadiabatic Dynamics Simulation Methods from Molecular to Extended Systems. J Phys Chem A 2022; 126:1789-1804. [PMID: 35266391 DOI: 10.1021/acs.jpca.1c10195] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Nonadiabatic dynamics simulation has become a powerful tool to describe nonadiabatic effects involved in photophysical processes and photochemical reactions. In the past decade, our group has developed generalized trajectory-based ab initio surface-hopping (GTSH) dynamics simulation methods, which can be used to describe a series of nonadiabatic processes, such as internal conversion, intersystem crossing, excitation energy transfer and charge transfer of molecular systems, and photoinduced nonadiabatic carrier dynamics of extended systems with and without spin-orbit couplings. In this contribution, we will first give a brief introduction to our recently developed methods and related numerical implementations at different computational levels. Later, we will present some of our latest applications in realistic systems, which cover organic molecules, biological proteins, organometallic compounds, periodic organic and inorganic materials, etc. Final discussion is given to challenges and outlooks of ab initio nonadiabatic dynamics simulations.
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Affiliation(s)
- Bin-Bin Xie
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou 311231, Zhejiang, P. R. China
| | - Pei-Ke Jia
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou 311231, Zhejiang, P. R. China
| | - Ke-Xin Wang
- Hangzhou Institute of Advanced Studies, Zhejiang Normal University, 1108 Gengwen Road, Hangzhou 311231, Zhejiang, P. R. China
| | - Wen-Kai Chen
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China
| | - Xiang-Yang Liu
- College of Chemistry and Material Science, Sichuan Normal University, Chengdu 610068, Sichuan, P. R. China
| | - Ganglong Cui
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education College of Chemistry, Beijing Normal University, Beijing 100875, P. R. China
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22
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Holland M, Ruth A, Mielczarek K, Dhas VV, Berry JJ, Irwin MD. Metal Halide Perovskites Demonstrate Radiation Hardness and Defect Healing in Vacuum. ACS APPLIED MATERIALS & INTERFACES 2022; 14:9352-9362. [PMID: 35142505 DOI: 10.1021/acsami.1c24709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Herein, we subject formamidinium lead iodide films to oxygen-containing gases (flowing O2 or free diffusion of lab atmosphere), inert gases (flowing He, Ar, or N2), and vacuum. Our films are irradiated by Cu Kα X-rays and held at 75 °C while X-ray diffraction is recorded. Under all gas conditions, we observe a reproducible 1.1 ± 0.5 Å3 perovskite lattice contraction from an initial unit cell volume of 256.5 ± 0.8 Å3 concurrent with continuous perovskite loss and lead iodide growth. Oxygen-containing gases increase the reaction rates without materially altering perovskite structural changes. Under the same temperature and irradiation conditions in vacuo, a self-healing reaction is observed, exhibited by a reproducible (0.9 ± 0.3 Å3) lattice expansion and stabilization of the perovskite. Interactions between the perovskite, defects, and minority phases are simulated by generalized gradient approximation Perdew-Burke-Ernzerhof (GGA-PBE) density functional theory. Lattice contraction indicates an increase in the concentration of Schottky defects─pairs of formamidinium and iodine vacancies. Under irradiation in every atmospheric condition, a solid solution of Schottky defects with a concentration of several percent diffuses and precipitates forming lead iodide and consuming the defects. In the presence of ionized gases, this framework is modified to include the continual loss of formamidinium and iodine ions from the perovskite forming Schottky defects.
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Affiliation(s)
- Michael Holland
- CubicPV Inc., 1807 Ross Avenue, Suite 333, Dallas, Texas 75201, United States
| | - Anthony Ruth
- CubicPV Inc., 1807 Ross Avenue, Suite 333, Dallas, Texas 75201, United States
| | - Kamil Mielczarek
- CubicPV Inc., 1807 Ross Avenue, Suite 333, Dallas, Texas 75201, United States
| | - Vivek V Dhas
- CubicPV Inc., 1807 Ross Avenue, Suite 333, Dallas, Texas 75201, United States
| | - Joseph J Berry
- National Renewable Energy Laboratory, Golden, Colorado 80401, United States
| | - Michael D Irwin
- CubicPV Inc., 1807 Ross Avenue, Suite 333, Dallas, Texas 75201, United States
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23
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Sabino FP, Zunger A, Dalpian GM. Intrinsic doping limitations in inorganic lead halide perovskites. MATERIALS HORIZONS 2022; 9:791-803. [PMID: 34904985 DOI: 10.1039/d1mh01371h] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Inorganic halide perovskites (HP's) of the CsPbX3 (X = I, Br, Cl) type have reached prominence in photovoltaic solar cell efficiencies, leading to the expectation that they are a new class of semiconductors relative to the traditional ones. Peculiarly, they have shown an asymmetry in their ability to be doped by holes vs. electrons. Indeed, both structural defect-induced doping as well as extrinsic impurity-induced doping strangely often result in HP's in a unipolar doping (dominantly p-type) with low free carriers' concentration. This raises the question whether such doping limitations presents just a temporary setback due to insufficient optimization of the doping process, or perhaps this represents an intrinsic, physically-mandated bottleneck. In this paper we study three fundamental Design Principles (DP's) for ideal doping, applying them via density functional doping theory to these HP's, thus identifying the violated DP that explains the doping limitations and asymmetry in these HP's. Here, the target DP are: (i) requires that the thermodynamic transition level between different charge states induced by the dopants must ideally be energetically shallow both for donors (n-type) or acceptors (p-type); DP-(ii) requires that the 'Fermi level pinning energies' for electrons E(n)pin and holes E(p)pin (being the limiting value of the Fermi level before a structural defect that compensate the doping forms spontaneously) should ideally be located inside the conduction band for n-type doping and inside the valence band for p-type doping. DP-(iii) requires that the doping-induced shift in equilibrium Fermi energy ΔE(n)F towards the conduction band for n-type doping (shift of ΔE(p)F towards the valence band, for p-type doping) to be sufficiently large. We find that, even though in HP's based on Br and Cl there are numerous shallow level dopants that satisfy DP-(i), in contrast DP-(ii) is satisfied only for holes and DP-(iii) fails for both holes and electrons, being the ultimate bottleneck for the n-type doping in Iodide HP's. This suggests an intrinsic mechanism for doping limitations in this class of semiconductors in terms of recognized physical mechanisms.
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Affiliation(s)
- Fernando P Sabino
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, 09210-580 Santo André, SP, Brazil.
| | - Alex Zunger
- Renewable and Sustainable Energy Institute, University of Colorado, Boulder, Colorado 80309, USA
| | - Gustavo M Dalpian
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, 09210-580 Santo André, SP, Brazil.
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24
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Wang S, Tse KF, Boyko A, Zhu J. Defect calculations using a combined SCAN and hybrid functional in γ-CsPbI 3. Phys Chem Chem Phys 2022; 24:3420-3428. [PMID: 35073394 DOI: 10.1039/d1cp04449d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
γ-CsPbI3 solar cells have achieved promising efficiencies, yet the quantitative understanding of their defect properties is limited due to the severe computational challenges when using hybrid functionals. We have discovered an algorithm to improve the convergence speed through a combination of structural relaxation with a strongly constrained and appropriately normed (SCAN) Meta-generalized-gradient approximation (Meta-GGA) functional and further ionic and electronic calculations with the Heyd-Scuseria-Ernzerhof (HSE) hybrid functional. The static HSE calculations with SCAN results as inputs are qualitatively reliable in defect calculations, different from one-ionic step HSE calculations based on GGA inputs. Contradictory to previous GGA defect results, a suppressed bipolar conductivity by p-type VCs and VPb, and n-type CsI is found. Additionally, stable bipolar defects Iint and CsPb, with features of strong bond orbital coupling or structural deformation, detrimentally serve as carrier-traps. This strengthened bond orbital coupling in γ-CsPbI3 causes more defect charge states than organic perovskites with larger lattice constants.
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Affiliation(s)
- Shengyuan Wang
- Department of Physics, The Chinese University of Hong Kong, Shatin, New Territory, Hong Kong SAR.
| | - Kin Fai Tse
- Department of Physics, The Chinese University of Hong Kong, Shatin, New Territory, Hong Kong SAR.
| | - Alena Boyko
- Department of Physics, The Chinese University of Hong Kong, Shatin, New Territory, Hong Kong SAR.
| | - Junyi Zhu
- Department of Physics, The Chinese University of Hong Kong, Shatin, New Territory, Hong Kong SAR.
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25
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Charge Compensation by Iodine Covalent Bonding in Lead Iodide Perovskite Materials. CRYSTALS 2022. [DOI: 10.3390/cryst12010088] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Metal halide perovskite materials (MHPs) are a family of next-generation semiconductors that are enabling low-cost, high-performance solar cells and optoelectronic devices. The most-used halogen in MHPs, iodine, can supplement its octet by covalent bonding resulting in atomic charges intermediate to I− and I0. Here, we examine theoretically stabilized defects of iodine using density functional theory (DFT); defect formation enthalpies and iodine Bader charges which illustrate how MHPs adapt to stoichiometry changes. Experimentally, X-ray photoelectron spectroscopy (XPS) is used to identify perovskite defects and their relative binding energies, and validate the predicted chemical environments of iodine defects. Examining MHP samples with excess iodine compared with near stoichiometric samples, we discern additional spectral intensity in the I 3d5/2 XPS data arising from defects, and support the presence of iodine trimers. I 3d5/2 defect peak areas reveal a ratio of 2:1, matching the number of atoms at the ends and middle of the trimer, whereas their binding energies agree with calculated Bader charges. Results suggest the iodine trimer is the preferred structural motif for incorporation of excess iodine into the perovskite lattice. Understanding these easily formed photoactive defects and how to identify their presence is essential for stabilizing MHPs against photodecomposition.
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26
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Feng Q, Zhang X, Nan G. Unveiling the Nature of Light-Triggered Hole Traps in Lead Halide Perovskites: A Study with Time-Dependent Density Functional Theory. J Phys Chem Lett 2021; 12:12075-12083. [PMID: 34910490 DOI: 10.1021/acs.jpclett.1c03652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Structural variations of lead halide perovskites (LHPs) upon light illumination play an important role in their photovoltaic applications. However, density functional theory (DFT)-based simulations have often been performed to unveil the nature of defects in LHPs without light illumination. So far, the nature of traps in LHPs triggered by the light remains largely unexplored. In this work, hole traps induced by the halogen interstitial in LHPs are studied by combining DFT and time-dependent DFT approaches, the latter of which treats electron-hole and electron-nuclei interactions on the same footing. Both a semilocal exchange functional and hybrid functional are adopted to relax the ground-state and excited-state geometries followed by the calculations of energy levels of hole traps. The effect of the self-interaction corrections on the light-triggered geometric deformation and the electronic structure of hole traps is analyzed. Relaxation energies that correspond to the light-triggered geometric deformation are also calculated with different functionals. The relationship between the hole traps and light-triggered geometric variations are then explored.
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Affiliation(s)
- Qingjie Feng
- Department of Physics, Zhejiang Normal University, Jinhua, Zhejiang 321004, P. R. China
| | - Xu Zhang
- Department of Physics and Astronomy, California State University Northridge, Northridge, California 91330-8268, United States
| | - Guangjun Nan
- Department of Physics, Zhejiang Normal University, Jinhua, Zhejiang 321004, P. R. China
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27
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Wang J, Duan X, Yin WJ. Photoinduced Dynamic Defects Responsible for the Giant, Reversible, and Bidirectional Light-Soaking Effect in Perovskite Solar Cells. J Phys Chem Lett 2021; 12:9328-9335. [PMID: 34546066 DOI: 10.1021/acs.jpclett.1c02929] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Perovskite solar cells (PSCs) exhibit large, reversible, and bidirectional light-soaking effects (LSEs); however, these anomalous LSEs are poorly understood, limiting the stability engineering and commercialization. We present a unified defect theory for the LSEs in lead halide perovskites by reconciling their defect photochemistry, ionic migration, and carrier dynamics. We considered typical detrimental defects (IPb, Ii, VI) and observed that two atomic configurations were favored, where the carrier lifetime of one configuration was nearly 1 order of magnitude longer than that in the other. First-principles calculations showed that light illumination promotes ion-diffusion-assisted transitions from energetically stable configurations to metastable configurations, which are converted back to stable configurations in the dark. Fermi-level-dependent formation energies of stable/metastable configurations were used to rationalize contradictory experimental results of anomalous LSEs in PSCs observed in various studies, thus providing insights for minimizing the LSE to achieve high-performance stable PSCs.
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Affiliation(s)
- Jing Wang
- College of Energy, Soochow Institute for Energy and Materials InnovationS (SIEMIS), Soochow University, Suzhou 215006, People's Republic of China
| | - Xiangmei Duan
- School of Physical Science and Technology, Ningbo University, Ningbo 315211, People's Republic of China
| | - Wan-Jian Yin
- College of Energy, Soochow Institute for Energy and Materials InnovationS (SIEMIS), Soochow University, Suzhou 215006, People's Republic of China
- Jiangsu Provincial Key Laboratory for Advanced Carbon Materials and Wearable Energy Technologies, Soochow University, Suzhou 215006, People's Republic of China
- Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province & Key Lab of Modern Optical Technologies of Education Ministry of China, Soochow University, Suzhou 215006, People's Republic of China
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28
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Keeble DJ, Wiktor J, Pathak SK, Phillips LJ, Dickmann M, Durose K, Snaith HJ, Egger W. Identification of lead vacancy defects in lead halide perovskites. Nat Commun 2021; 12:5566. [PMID: 34552098 PMCID: PMC8458286 DOI: 10.1038/s41467-021-25937-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 09/03/2021] [Indexed: 11/11/2022] Open
Abstract
Perovskite photovoltaics advance rapidly, but questions remain regarding point defects: while experiments have detected the presence of electrically active defects no experimentally confirmed microscopic identifications have been reported. Here we identify lead monovacancy (VPb) defects in MAPbI3 (MA = CH3NH3+) using positron annihilation lifetime spectroscopy with the aid of density functional theory. Experiments on thin film and single crystal samples all exhibited dominant positron trapping to lead vacancy defects, and a minimum defect density of ~3 × 1015 cm-3 was determined. There was also evidence of trapping at the vacancy complex [Formula: see text] in a minority of samples, but no trapping to MA-ion vacancies was observed. Our experimental results support the predictions of other first-principles studies that deep level, hole trapping, [Formula: see text], point defects are one of the most stable defects in MAPbI3. This direct detection and identification of a deep level native defect in a halide perovskite, at technologically relevant concentrations, will enable further investigation of defect driven mechanisms.
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Affiliation(s)
- David J Keeble
- Physics, SUPA, School of Science and Engineering, University of Dundee, Dundee, DD1 4HN, UK.
| | - Julia Wiktor
- Department of Physics, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden
| | - Sandeep K Pathak
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, OX1 3PU, UK
- Centre for Energy Studies, Indian Institute of Technology Delhi, New Delhi, 110016, India
| | - Laurie J Phillips
- Stephenson Institute for Renewable Energy, Department of Physics, University of Liverpool, Liverpool, L69 7ZF, UK
| | - Marcel Dickmann
- Physics Department and Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, D-85748, Garching, Germany
- Institut für Angewandte Physik und Messtechnik, Universität der Bundeswehr München, D-85579, Neubiberg, Germany
| | - Ken Durose
- Stephenson Institute for Renewable Energy, Department of Physics, University of Liverpool, Liverpool, L69 7ZF, UK
| | - Henry J Snaith
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, OX1 3PU, UK
| | - Werner Egger
- Institut für Angewandte Physik und Messtechnik, Universität der Bundeswehr München, D-85579, Neubiberg, Germany
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29
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Repair Strategies for Perovskite Solar Cells. Chem Res Chin Univ 2021. [DOI: 10.1007/s40242-021-1334-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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30
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Park JS, Jung J, Lee S. Cost-Effective High-Throughput Calculation Based on Hybrid Density Functional Theory: Application to Cubic, Double, and Vacancy-Ordered Halide Perovskites. J Phys Chem Lett 2021; 12:7885-7891. [PMID: 34382798 DOI: 10.1021/acs.jpclett.1c02244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Hybrid density functional theory calculations are commonly used to investigate the electronic structure of semiconductor materials but have not been ideal for high-throughput calculations due to heavy computation costs. We developed a computational approach to obtain the electronic band gap cost-effectively by employing not only non-self-consistent field calculation methods but also sparse k-point meshes for the Fock exchange potential. The benchmark calculation showed that our method is at least 30 times faster than the conventional hybrid density functional theory calculation to quickly screen materials. The band gaps of 290 materials in 5 different structures including cubic, double, and vacancy-ordered perovskites were obtained. The physical properties of Cs2WCl6 and Cs2NaInBr6, screened for optoelectronic applications, were in good agreement with the experiment.
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Affiliation(s)
- Ji-Sang Park
- Department of Physics, Kyungpook National University, Daegu 41566, South Korea
| | - Jina Jung
- School of Materials Science and Engineering, Kyungpook National University, Daegu 41566, South Korea
| | - Sangwook Lee
- School of Materials Science and Engineering, Kyungpook National University, Daegu 41566, South Korea
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31
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Kar M, Ghosh A, Sarkar R, Pal S, Sarkar P. Arene and functionalized arene based two dimensional organic-inorganic hybrid perovskites for photovoltaic applications. J Comput Chem 2021; 42:1982-1990. [PMID: 34390256 DOI: 10.1002/jcc.26731] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 06/23/2021] [Accepted: 07/25/2021] [Indexed: 11/12/2022]
Abstract
Recently, two-dimensional organic-inorganic hybrid perovskites have attracted great attention for their outstanding performances in solar energy conversion devices. By using first principles calculations, we explored the structural, electronic and optical properties of recently synthesized (PEA)2 PbI4 and (PEA)2 SnI4 organic-inorganic hybrid perovskites to understand the photovoltaic performances of these systems. Our study reveals that both the perovskites are direct band gap semiconductors and possess desirable band gap for solar energy absorption. We have further extended our study to fluoro-, chloro-, and bromo-functionalized phenethylammonium (PEA) cations based [X(X = F, Cl, Br)PEA]2 A(A = Pb, Sn)I4 perovskite materials. The halogenated benzene moiety confers an ultrahydrophobic character and protects the perovskites from ambient moisture. The halogen functionalized perovskites remain direct band gap semiconductors and all the perovskites show very strong optical absorption (∼7 × 105 cm-1 ) across UV-visible region. We have further calculated the photo-conversion efficiency (PCE) of both arene and functionalized arene based perovskites. The halogen-functionalized PEA-based perovskites also exhibit high PCE as like pristine ones and finally achieve high PCE of up to 24.30%, making them competitive with other previously reported perovskite-based photovoltaic devices.
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Affiliation(s)
- Moumita Kar
- Department of Chemistry, Visva-Bharati University, Santiniketan, India
| | - Atish Ghosh
- Department of Chemistry, Visva-Bharati University, Santiniketan, India
| | | | - Sougata Pal
- Department of Chemistry, University of Gour Banga, Malda, India
| | - Pranab Sarkar
- Department of Chemistry, Visva-Bharati University, Santiniketan, India
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32
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Lei Y, Xu Y, Wang M, Zhu G, Jin Z. Origin, Influence, and Countermeasures of Defects in Perovskite Solar Cells. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2005495. [PMID: 33759357 DOI: 10.1002/smll.202005495] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 11/24/2020] [Indexed: 05/08/2023]
Abstract
Defects are considered to be one of the most significant factors that compromise the power conversion efficiencies and long-term stability of perovskite solar cells. Therefore, it is urgent to have a profound understanding of their formation and influence mechanism, so as to take corresponding measures to suppress or even completely eliminate their adverse effects on device performance. Herein, the possible origins of the defects in metal halide perovskite films and their impacts on the device performance are analyzed, and then various methods to reduce defect density are introduced in detail. Starting from the internal and interfacial aspects of the metal halide perovskite films, several ways to improve device performance and long-term stability including additive engineering, surface passivation, and other physical treatments (annealing engineering), etc., are further elaborated. Finally, the further understanding of defects and the development trend of passivation strategies are prospected.
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Affiliation(s)
- Yutian Lei
- School of Physical Science and Technology & Key Laboratory of Special Function Materials and Structure Design (MoE) & National & Local Joint Engineering Laboratory for Optical Conversion Materials and Technology, Lanzhou University, Lanzhou, 730000, China
| | - Youkui Xu
- School of Physical Science and Technology & Key Laboratory of Special Function Materials and Structure Design (MoE) & National & Local Joint Engineering Laboratory for Optical Conversion Materials and Technology, Lanzhou University, Lanzhou, 730000, China
| | - Meng Wang
- School of Physical Science and Technology & Key Laboratory of Special Function Materials and Structure Design (MoE) & National & Local Joint Engineering Laboratory for Optical Conversion Materials and Technology, Lanzhou University, Lanzhou, 730000, China
| | - Ge Zhu
- Key Laboratory of New Energy and Rare Earth Resource Utilization of State Ethnic Affairs Commission, Key Laboratory of Photosensitive Materials & Devices of Liaoning Province, College of Physics and Materials Engineering, Dalian Minzu University, 18 Liaohe West Road, Dalian, 116600, China
| | - Zhiwen Jin
- School of Physical Science and Technology & Key Laboratory of Special Function Materials and Structure Design (MoE) & National & Local Joint Engineering Laboratory for Optical Conversion Materials and Technology, Lanzhou University, Lanzhou, 730000, China
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33
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Zhang X, Shen JX, Turiansky ME, Van de Walle CG. Minimizing hydrogen vacancies to enable highly efficient hybrid perovskites. NATURE MATERIALS 2021; 20:971-976. [PMID: 33927392 DOI: 10.1038/s41563-021-00986-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 03/15/2021] [Indexed: 06/12/2023]
Abstract
Defect-induced non-radiative losses are currently limiting the performance of hybrid perovskite devices. Experimental reports have indicated the existence of point defects that act as detrimental non-radiative recombination centres under iodine-poor synthesis conditions. However, the microscopic nature of these defects is still unknown. Here we demonstrate that hydrogen vacancies can be present in high densities under iodine-poor conditions in the prototypical hybrid perovskite MAPbI3 (MA = CH3NH3). They act as very efficient non-radiative recombination centres with an exceptionally high carrier capture coefficient of 10-4 cm3 s-1. By contrast, the hydrogen vacancies in FAPbI3 [FA = CH(NH2)2] are much more difficult to form and have a capture coefficient that is three orders of magnitude lower. Our study unveils the critical but overlooked role of hydrogen vacancies in hybrid perovskites and rationalizes why FA is essential for realizing high efficiency in hybrid perovskite solar cells. Minimizing the incorporation of hydrogen vacancies is key to enabling the best performance of hybrid perovskites.
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Affiliation(s)
- Xie Zhang
- Materials Department, University of California, Santa Barbara, CA, USA.
- Materials and Energy Division, Beijing Computational Science Research Center, Beijing, China.
| | - Jimmy-Xuan Shen
- Department of Physics, University of California, Santa Barbara, CA, USA
| | - Mark E Turiansky
- Department of Physics, University of California, Santa Barbara, CA, USA
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34
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Li W, She Y, Vasenko AS, Prezhdo OV. Ab initio nonadiabatic molecular dynamics of charge carriers in metal halide perovskites. NANOSCALE 2021; 13:10239-10265. [PMID: 34031683 DOI: 10.1039/d1nr01990b] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Photoinduced nonequilibrium processes in nanoscale materials play key roles in photovoltaic and photocatalytic applications. This review summarizes recent theoretical investigations of excited state dynamics in metal halide perovskites (MHPs), carried out using a state-of-the-art methodology combining nonadiabatic molecular dynamics with real-time time-dependent density functional theory. The simulations allow one to study evolution of charge carriers at the ab initio level and in the time-domain, in direct connection with time-resolved spectroscopy experiments. Eliminating the need for the common approximations, such as harmonic phonons, a choice of the reaction coordinate, weak electron-phonon coupling, a particular kinetic mechanism, and perturbative calculation of rate constants, we model full-dimensional quantum dynamics of electrons coupled to semiclassical vibrations. We study realistic aspects of material composition and structure and their influence on various nonequilibrium processes, including nonradiative trapping and relaxation of charge carriers, hot carrier cooling and luminescence, Auger-type charge-charge scattering, multiple excitons generation and recombination, charge and energy transfer between donor and acceptor materials, and charge recombination inside individual materials and across donor/acceptor interfaces. These phenomena are illustrated with representative materials and interfaces. Focus is placed on response to external perturbations, formation of point defects and their passivation, mixed stoichiometries, dopants, grain boundaries, and interfaces of MHPs with charge transport layers, and quantum confinement. In addition to bulk materials, perovskite quantum dots and 2D perovskites with different layer and spacer cation structures, edge passivation, and dielectric screening are discussed. The atomistic insights into excited state dynamics under realistic conditions provide the fundamental understanding needed for design of advanced solar energy and optoelectronic devices.
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Affiliation(s)
- Wei Li
- School of Chemistry and Materials Science, Hunan Agricultural University, Changsha 410128, People's Republic of China.
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35
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Pious JK, Basavarajappa MG, Muthu C, Nishikubo R, Saeki A, Chakraborty S, Takai A, Takeuchi M, Vijayakumar C. Self-Assembled Organic Cations-Assisted Band-Edge Tailoring in Bismuth-Based Perovskites for Enhanced Visible Light Absorption and Photoconductivity. J Phys Chem Lett 2021; 12:5758-5764. [PMID: 34133185 DOI: 10.1021/acs.jpclett.1c01321] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Bismuth-based zero-dimensional perovskites garner high research interest because of their advantages, such as excellent moisture stability and lower toxicity in comparison to lead-based congeners. However, the wide optical bandgap (>2 eV) and poor photoconductivity of these materials are the bottlenecks for their optoelectronic applications. Herein, we report a combined experimental and theoretical study of the structural features and optoelectronic properties of two novel and stable zero-dimensional bismuth perovskites: (biphenyl bis(methylammonium))1.5BiI6·2H2O (BPBI) and (naphthalene diimide bis(ethylammonium))1.5BiI6·2H2O (NDBI). NDBI features a remarkably narrower bandgap (1.82 eV) than BPBI (2.06 eV) because of the significant orbital contribution of self-assembled naphthalene diimide cations at the band edges of NDBI. Further, the FP-TRMC analysis revealed that the photoconductivity of NDBI is about 3.7-fold greater than that of BPBI. DFT calculations showed that the enhanced photoconductivity in NDBI arises from its type-IIa band alignment, whereas type-Ib alignment was seen in BPBI.
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Affiliation(s)
- Johnpaul K Pious
- Photosciences and Photonics Section, CSIR-National Institute for Interdisciplinary Science and Technology (NIIST), Thiruvananthapuram 695 019, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201 002, India
| | - Manasa G Basavarajappa
- Discipline of Physics, Indian Institute of Technology Indore, Simrol, Indore 453 552, India
- Materials Theory for Energy Scavenging (MATES) Lab, Harish-Chandra Research Institute (HRI) Allahabad, HBNI, Chhatnag Road, Jhusi 211 019, India
| | - Chinnadurai Muthu
- Photosciences and Photonics Section, CSIR-National Institute for Interdisciplinary Science and Technology (NIIST), Thiruvananthapuram 695 019, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201 002, India
| | - Ryosuke Nishikubo
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565 0871, Japan
| | - Akinori Saeki
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565 0871, Japan
| | - Sudip Chakraborty
- Discipline of Physics, Indian Institute of Technology Indore, Simrol, Indore 453 552, India
- Materials Theory for Energy Scavenging (MATES) Lab, Harish-Chandra Research Institute (HRI) Allahabad, HBNI, Chhatnag Road, Jhusi 211 019, India
| | - Atsuro Takai
- Molecular Design and Function Group, National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba 305 0047, Japan
| | - Masayuki Takeuchi
- Molecular Design and Function Group, National Institute for Materials Science (NIMS), 1-2-1 Sengen, Tsukuba 305 0047, Japan
| | - Chakkooth Vijayakumar
- Photosciences and Photonics Section, CSIR-National Institute for Interdisciplinary Science and Technology (NIIST), Thiruvananthapuram 695 019, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201 002, India
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36
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Ceratti DR, Cohen AV, Tenne R, Rakita Y, Snarski L, Jasti NP, Cremonesi L, Cohen R, Weitman M, Rosenhek-Goldian I, Kaplan-Ashiri I, Bendikov T, Kalchenko V, Elbaum M, Potenza MAC, Kronik L, Hodes G, Cahen D. The pursuit of stability in halide perovskites: the monovalent cation and the key for surface and bulk self-healing. MATERIALS HORIZONS 2021; 8:1570-1586. [PMID: 34846465 DOI: 10.1039/d1mh00006c] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
We find significant differences between degradation and healing at the surface or in the bulk for each of the different APbBr3 single crystals (A = CH3NH3+, methylammonium (MA); HC(NH2)2+, formamidinium (FA); and cesium, Cs+). Using 1- and 2-photon microscopy and photobleaching we conclude that kinetics dominate the surface and thermodynamics the bulk stability. Fluorescence-lifetime imaging microscopy, as well as results from several other methods, relate the (damaged) state of the halide perovskite (HaP) after photobleaching to its modified optical and electronic properties. The A cation type strongly influences both the kinetics and the thermodynamics of recovery and degradation: FA heals best the bulk material with faster self-healing; Cs+ protects the surface best, being the least volatile of the A cations and possibly through O-passivation; MA passivates defects via methylamine from photo-dissociation, which binds to Pb2+. DFT simulations provide insight into the passivating role of MA, and also indicate the importance of the Br3- defect as well as predicts its stability. The occurrence and rate of self-healing are suggested to explain the low effective defect density in the HaPs and through this, their excellent performance. These results rationalize the use of mixed A-cation materials for optimizing both solar cell stability and overall performance of HaP-based devices, and provide a basis for designing new HaP variants.
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Affiliation(s)
- D R Ceratti
- Weizmann Institute of Science, Department of Materials and Interfaces, 7610001, Rehovot, Israel.
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Kim YS, Ri CH, Ko UH, Kye YH, Jong UG, Yu CJ. Interfacial Enhancement of Photovoltaic Performance in MAPbI 3/CsPbI 3 Superlattice. ACS APPLIED MATERIALS & INTERFACES 2021; 13:14679-14687. [PMID: 33726490 DOI: 10.1021/acsami.0c22550] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Perovskite solar cells have continued to fascinate over the past decade due to fast increasing power conversion efficiency and very low fabrication cost but still suffered from poor stability. Interface engineering is evolved to be one of the most promising solutions to the instability problem. In this work, we perform a first-principles study on the MAPbI3/CsPbI3 interface system, aiming at clarifying the underlying mechanism of interfacial enhancement of solar cell performance. We devise the atomistic modeling of superlattices as increasing the number of included unit cells and carry out structural optimizations, revealing that the binding strength between the perovskite layers becomes stronger while the band gap decreases as the supercell size increases. Using enough large supercells of the interface system, we further estimate the formation energies of the interfacial vacancy defects and activation barriers for vacancy-mediated I atom migrations. Our calculations show the shallow transition states for most of the defects and the higher activation barriers for I atom migrations across the interface, providing an evidence of performance enhancement by the interface formation. By giving an insightful understanding of the MAPbI3/CsPbI3 heterojunction, this work definitely contributes to the design of interface systems for high-performance solar cells.
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Affiliation(s)
- Yun-Sim Kim
- Chair of Computational Materials Design, Faculty of Materials Science, Kim Il Sung University, P.O. Box 76, Ryongnam-Dong, Taesong District, Pyongyang, Democratic People's Republic of Korea
| | - Chol-Hyok Ri
- Chair of Computational Materials Design, Faculty of Materials Science, Kim Il Sung University, P.O. Box 76, Ryongnam-Dong, Taesong District, Pyongyang, Democratic People's Republic of Korea
| | - Un-Hyok Ko
- Chair of Computational Materials Design, Faculty of Materials Science, Kim Il Sung University, P.O. Box 76, Ryongnam-Dong, Taesong District, Pyongyang, Democratic People's Republic of Korea
| | - Yun-Hyok Kye
- Chair of Computational Materials Design, Faculty of Materials Science, Kim Il Sung University, P.O. Box 76, Ryongnam-Dong, Taesong District, Pyongyang, Democratic People's Republic of Korea
| | - Un-Gi Jong
- Chair of Computational Materials Design, Faculty of Materials Science, Kim Il Sung University, P.O. Box 76, Ryongnam-Dong, Taesong District, Pyongyang, Democratic People's Republic of Korea
| | - Chol-Jun Yu
- Chair of Computational Materials Design, Faculty of Materials Science, Kim Il Sung University, P.O. Box 76, Ryongnam-Dong, Taesong District, Pyongyang, Democratic People's Republic of Korea
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38
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Yang JJ, Liu XY, Li ZW, Frauenheim T, Yam C, Fang WH, Cui G. The spin-orbit interaction controls photoinduced interfacial electron transfer in fullerene-perovskite heterojunctions: C 60versus C 70. Phys Chem Chem Phys 2021; 23:6536-6543. [PMID: 33690742 DOI: 10.1039/d0cp06579j] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Here, we used collinear and noncollinear density functional theory (DFT) methods to explore the interfacial properties of two heterojunctions between a fullerene (C60 and C70) and the MAPbI3(110) surface. Methodologically, consideration of the spin-orbit interaction has been proven to be required to obtain accurate energy-level alignment and interfacial carrier dynamics between fullerenes and perovskites in hybrid perovskite solar cells including heavy atoms (such as Pb atoms). Both heterojunctions are predicted to be the same type-II heterojunction, but the interfacial electron transfer process from MAPbI3 to C60 is completely distinct from that to C70. In the former, the interfacial electron transfer is slow because of the associated large energy gap, and the excited electrons are thus trapped in MAPbI3 for a while. In contrast, in the latter, the smaller energy gap induces ultrafast electron transfer from MAPbI3 to C70. These points are further supported by DFT-based nonadiabatic dynamics simulations including the spin-orbit coupling (SOC) effects. These gained insights could help rationally design superior fullerene-perovskite interfaces to achieve high power conversion efficiencies of fullerene-perovskite solar cells.
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Affiliation(s)
- Jia-Jia Yang
- College of Chemistry, Beijing Normal University, Beijing 100875, China.
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39
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Guan Y, Zhang X, Nan G. Frenkel defects promote polaronic exciton dissociation in methylammonium lead iodide perovskites. Phys Chem Chem Phys 2021; 23:6583-6590. [PMID: 33704338 DOI: 10.1039/d1cp00222h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Hybrid organic-inorganic perovskite materials, such as CH3NH3PbI3, exhibit substantial potential in a variety of optoelectronic applications. Nevertheless, the interplay between the photoinduced excitations and iodine Frenkel defects which are abundant in CH3NH3PbI3 films remains poorly understood. Here we study the light-triggered electronic and excitonic properties in the presence of iodine Frenkel defects in CH3NH3PbI3 by using a combination of density functional theory (DFT) and time-dependent DFT approaches, the latter of which treats electron-hole and electron-nucleus interactions on the same footing. For isolated Frenkel defects, electrons are trapped close to the iodine vacancies and the electron-hole correlation brings the holes in close vicinity to the electrons, yielding tightly bound polaronic excitons. However, in the presence of multiple interactive Frenkel defects, the holes are pulled out from an electron-hole Coulomb well by the iodine interstitials, leading to spatially separated electron-hole pairs. The X-ray photoelectron spectra are then simulated, unravelling the light-triggered charge transfer induced by Frenkel defects at the atomistic level. We also find that the energy and spatial distributions of polaronic excitons at the Frenkel defects can be controlled by the dynamical rotation of organic cations.
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Affiliation(s)
- Yuhan Guan
- Department of Physics, Zhejiang Normal University, Jinhua, Zhejiang 321004, P. R. China.
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40
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Liu XY, Yang JJ, Chen WK, Akimov AV, Fang WH, Cui G. Spin-Orbit Coupling Accelerates the Photoinduced Interfacial Electron Transfer in a Fullerene-Based Perovskite Heterojunction. J Phys Chem Lett 2021; 12:1131-1137. [PMID: 33475363 DOI: 10.1021/acs.jpclett.0c03782] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
In this work, we explore the interfacial properties of the C60-Py@MAPbI3 heterojunction of the PbI-terminated MAPbI3(001) surface and pyridine-functionalized C60-Py fullerene derivative through both collinear and noncollinear density functional theory calculations with and without spin-orbit coupling (SOC) effects. C60-Py is bound to the MAPbI3 surface through interfacial Pb-O and Pb-N bonds. Although C60-Py@MAPbI3 is predicted to be the same type II heterojunction at all of the computational levels considered, the SOC effects largely decrease the energy gap of the first conduction bands of C60-Py and MAPbI3, thereby accelerating the interfacial electron transfer. Further dynamics simulations show that the inclusion of the SOC effects induces the transfer of approximately 80% of electrons from MAPbI3 to C60-Py within 1 ps. The work demonstrates that the SOC effects are indispensable for the interfacial properties of C60-Py@MAPbI3 and could also play a non-negligible role in tuning the optoelectronic properties of fullerene-based or similar perovskite devices.
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Affiliation(s)
- Xiang-Yang Liu
- College of Chemistry and Material Science, Sichuan Normal University, Chengdu 610068, China
| | - Jia-Jia Yang
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Wen-Kai Chen
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Alexey V Akimov
- Department of Chemistry, University at Buffalo, The State University of New York, Buffalo, New York 14260, United States
| | - Wei-Hai Fang
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
| | - Ganglong Cui
- Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, China
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41
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Ouedraogo NAN, Yan H, Han CB, Zhang Y. Influence of Fluorinated Components on Perovskite Solar Cells Performance and Stability. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2004081. [PMID: 33522104 DOI: 10.1002/smll.202004081] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 10/12/2020] [Indexed: 06/12/2023]
Abstract
Several valuable scientific investigations have been conducted these last few years in materials design and device engineering for perovskite solar cells (PSCs) to make them competitive compared to traditional silicon-based photovoltaic technologies. Consequently, high power conversion efficiency beyond 25% is nowadays reported. However, their long-term stability remains a significant challenge to overcome. Herein, the influence of fluorinated compounds on each layer of PSCs devices and their impact on the resulted device performances and stability is spotlighted. The fluorinated compounds exhibit attractive properties due to their very high electronegativity attributed to the fluorine atom, and their strong hydrophobicity. Thus, the introduction of these compounds is found to be a successful strategy to positively suppress the surface trap states, enhancing charge collection and reducing interfacial charge recombination. Besides, a better film quality and better energy level alignment is obtained, resulting in the improvement of device photovoltaic parameters such as the open-circuit voltage (Voc ), short-circuit current (Jsc ), and fill factor (FF), and then, the device's overall power conversion efficiency (PCE). Their long-term stability is also found to further be improved.
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Affiliation(s)
- Nabonswende Aida Nadege Ouedraogo
- College of Materials Science and Engineering, Beijing University of Technology, Beijing, 100124, China
- The Key Laboratory of Advanced Functional Materials, Ministry of Education of China, Beijing, 100124, China
| | - Hui Yan
- College of Materials Science and Engineering, Beijing University of Technology, Beijing, 100124, China
- The Key Laboratory of Advanced Functional Materials, Ministry of Education of China, Beijing, 100124, China
| | - Chang Bao Han
- College of Materials Science and Engineering, Beijing University of Technology, Beijing, 100124, China
- The Key Laboratory of Advanced Functional Materials, Ministry of Education of China, Beijing, 100124, China
| | - Yongzhe Zhang
- College of Materials Science and Engineering, Beijing University of Technology, Beijing, 100124, China
- The Key Laboratory of Advanced Functional Materials, Ministry of Education of China, Beijing, 100124, China
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42
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Han D, Ebert H. Identification of Potential Optoelectronic Applications for Metal Thiophosphates. ACS APPLIED MATERIALS & INTERFACES 2021; 13:3836-3844. [PMID: 33445861 DOI: 10.1021/acsami.0c17818] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Metal thiophosphates are a large family of compounds that received far less attention than conventional chalcogenides. Recently, however, metal thiophosphates arouse research interest in regard of energy harvesting and conversion due to their structural and chemical diversity. Nevertheless, there remain many unexplored metal thiophosphates. Here, we performed a comprehensive investigation on the electronic and optoelectronic properties of a series of metal thiophosphates using first-principles calculations and identified several highly promising compounds as p-type transparent conductors, photovoltaic absorbers, and single visible-light-driven photocatalysts for water splitting. Our investigation reveals the intrinsic features of a series of typical metal thiophosphates, identifies their new optoelectronic applications, and validates that metal thiophosphates are promising materials deserving exploration.
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Affiliation(s)
- Dan Han
- Department of Chemie, Ludwig-Maximilians-Universität München, München 81377, Germany
| | - Hubert Ebert
- Department of Chemie, Ludwig-Maximilians-Universität München, München 81377, Germany
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43
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Jeong JE, Park JH, Jang CH, Song MH, Woo HY. Multifunctional Charge Transporting Materials for Perovskite Light-Emitting Diodes. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e2002176. [PMID: 32886378 DOI: 10.1002/adma.202002176] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 05/03/2020] [Indexed: 06/11/2023]
Abstract
Despite their low exciton-binding energies, metal halide perovskites are extensively studied as light-emitting materials owing to narrow emission with high color purity, easy/wide color tunability, and high photoluminescence quantum yields. To improve the efficiency of perovskite light-emitting diodes (PeLEDs), much effort has been devoted to controlling the emitting layer morphologies to induce charge confinement and decrease the nonradiative recombination. The interfaces between the emitting layer and charge transporting layer (CTL) are vulnerable to various defects that deteriorate the efficiency and stability of the PeLEDs. Therefore, the establishment of multifunctional CTLs that can improve not only charge transport but also critical factors that influence device performance, such as defect passivation, morphology/phase control, ion migration suppression, and light outcoupling efficiency, are highly required. Herein, the fundamental limitations of perovskites as emitters (i.e., defects, morphological and phase instability, high refractive index with poor outcoupling) and the recent developments with regard to multifunctional CTLs to compensate such limitations are summarized, and their device applications are also reviewed. Finally, based on the importance of multifunctional CTLs, the outlook and research prospects of multifunctional CTLs for the further improvement of PeLEDs are discussed.
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Affiliation(s)
- Ji-Eun Jeong
- Department of Chemistry, Korea University, Anam-ro 145, Seoul, 02841, Republic of Korea
| | - Jong Hyun Park
- School of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), UNIST-gil 50, Ulsan, 44919, Republic of Korea
| | - Chung Hyeon Jang
- School of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), UNIST-gil 50, Ulsan, 44919, Republic of Korea
| | - Myoung Hoon Song
- School of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), UNIST-gil 50, Ulsan, 44919, Republic of Korea
| | - Han Young Woo
- Department of Chemistry, Korea University, Anam-ro 145, Seoul, 02841, Republic of Korea
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44
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Qiu X, Liu Y, Li W, Hu Y. Traps in metal halide perovskites: characterization and passivation. NANOSCALE 2020; 12:22425-22451. [PMID: 33151219 DOI: 10.1039/d0nr05739h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Metal halide perovskites (MHPs) have become a research focus in the field of optoelectronics due to their excellent optoelectronic properties and simple and cost-effective thin film manufacturing processes. In particular, the power conversion efficiency (PCE) of solar cells (SCs) and external quantum efficiency (EQE) of light-emitting diodes (LEDs) based on perovskite materials have reached 25.2% and 21.6%, respectively, in a short period, making perovskites especially promising for fabricating next-generation optoelectronic devices. Despite these inspiring results, obtaining high-performance, high-stability MHP-based devices still faces many challenges, among which the defects and the consequent traps in MHPs are key factors. Defect-induced traps can trap charge carriers or even act as non-radiative recombination centers, seriously degrading the device performance, causing hysteresis and deteriorating the stability of MHP-based devices. Thus, understanding the chemical/physical nature of traps and adopting appropriate strategies to passivate traps are important to enhance the device performance and stability. Herein we present a review in which the knowledge and understanding of traps in MHPs are considered and discussed. Moreover, the latest efforts on passivating traps in MHPs for improving device performance are summarized, with the hope of providing guidance to future development of high-performance and high-stability MHP-based devices.
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Affiliation(s)
- Xincan Qiu
- Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education and Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices, School of Physics and Electronics, Hunan University, Changsha 410082, China.
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45
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Musiienko A, Pipek J, Praus P, Brynza M, Belas E, Dryzhakov B, Du MH, Ahmadi M, Grill R. Deciphering the effect of traps on electronic charge transport properties of methylammonium lead tribromide perovskite. SCIENCE ADVANCES 2020; 6:6/37/eabb6393. [PMID: 32917707 PMCID: PMC7486106 DOI: 10.1126/sciadv.abb6393] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Accepted: 07/29/2020] [Indexed: 05/17/2023]
Abstract
Halide perovskites have undergone remarkable developments as highly efficient optoelectronic materials for a variety of applications. Several studies indicated the critical role of defects on the performance of perovskite devices. However, the parameters of defects and their interplay with free charge carriers remain unclear. In this study, we explored the dynamics of free holes in methylammonium lead tribromide (MAPbBr3) single crystals using the time-of-flight (ToF) current spectroscopy. By combining ToF spectroscopy and Monte Carlo simulation, three energy states were detected in the bandgap of MAPbBr3 In addition, we found the trapping and detrapping rates of free holes ranging from a few microseconds to hundreds of microseconds. Contrary to previous studies, we revealed a strong detrapping activity of traps. We showed that these traps substantially affect the transport properties of MAPbBr3, including mobility and mobility-lifetime product. Our results provide an insight on charge transport properties of perovskite semiconductors.
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Affiliation(s)
- Artem Musiienko
- Charles University, Faculty of Mathematics and Physics, Institute of Physics, Ke Karlovu 5, CZ-121 16 Prague 2, Czech Republic.
| | - Jindřich Pipek
- Charles University, Faculty of Mathematics and Physics, Institute of Physics, Ke Karlovu 5, CZ-121 16 Prague 2, Czech Republic
| | - Petr Praus
- Charles University, Faculty of Mathematics and Physics, Institute of Physics, Ke Karlovu 5, CZ-121 16 Prague 2, Czech Republic
| | - Mykola Brynza
- Charles University, Faculty of Mathematics and Physics, Institute of Physics, Ke Karlovu 5, CZ-121 16 Prague 2, Czech Republic
| | - Eduard Belas
- Charles University, Faculty of Mathematics and Physics, Institute of Physics, Ke Karlovu 5, CZ-121 16 Prague 2, Czech Republic
| | - Bogdan Dryzhakov
- Joint Institute for Advanced Materials, Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37996, USA
| | - Mao-Hua Du
- Oak Ridge National Laboratory, Materials Science and Technology Division, Oak Ridge, TN 37831, USA
| | - Mahshid Ahmadi
- Joint Institute for Advanced Materials, Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37996, USA.
| | - Roman Grill
- Charles University, Faculty of Mathematics and Physics, Institute of Physics, Ke Karlovu 5, CZ-121 16 Prague 2, Czech Republic
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Zhang S, Shaw PE, Zhang G, Jin H, Tai M, Lin H, Meredith P, Burn PL, Neher D, Stolterfoht M. Defect/Interface Recombination Limited Quasi-Fermi Level Splitting and Open-Circuit Voltage in Mono- and Triple-Cation Perovskite Solar Cells. ACS APPLIED MATERIALS & INTERFACES 2020; 12:37647-37656. [PMID: 32678571 DOI: 10.1021/acsami.0c02960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Multication metal-halide perovskites exhibit desirable performance and stability, compared to their monocation counterparts. However, the study of the photophysical properties and the nature of defect states in these materials is still a challenging and ongoing task. Here, we study bulk and interfacial energy loss mechanisms in solution-processed MAPbI3 (MAPI) and (CsPbI3)0.05[(FAPbI3)0.83(MAPbBr3)0.17]0.95 (triple cation) perovskite solar cells using absolute photoluminescence (PL) measurements. In neat MAPI films, we find a significantly smaller quasi-Fermi level splitting than for the triple cation perovskite absorbers, which defines the open-circuit voltage of the MAPI cells. PL measurements at low temperatures (∼20 K) on MAPI films demonstrate that emissive subgap states can be effectively reduced using different passivating agents, which lowers the nonradiative recombination loss at room temperature. We conclude that while triple cation perovskite cells are limited by interfacial recombination, the passivation of surface trap states within the MAPI films is the primary consideration for device optimization.
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Affiliation(s)
- Shanshan Zhang
- Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Str. 24-25, D-14476 Potsdam-Golm, Germany
- Centre for Organic Photonics & Electronics (COPE), School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane 4072, Australia
| | - Paul E Shaw
- Centre for Organic Photonics & Electronics (COPE), School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane 4072, Australia
| | - Guanran Zhang
- Centre for Organic Photonics & Electronics (COPE), School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane 4072, Australia
| | - Hui Jin
- Centre for Organic Photonics & Electronics (COPE), School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane 4072, Australia
| | - Meiqian Tai
- School of Materials Science and Engineering, Tsinghua University, Beijing 100084, P.R.China
| | - Hong Lin
- School of Materials Science and Engineering, Tsinghua University, Beijing 100084, P.R.China
| | - Paul Meredith
- Department of Physics, Swansea University, Singleton Park, Swansea SA2 8PP Wales, United Kingdom
| | - Paul L Burn
- Centre for Organic Photonics & Electronics (COPE), School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane 4072, Australia
| | - Dieter Neher
- Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Str. 24-25, D-14476 Potsdam-Golm, Germany
| | - Martin Stolterfoht
- Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Str. 24-25, D-14476 Potsdam-Golm, Germany
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47
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Li D, Li D, Zhang H, Yang A, Liang C. High-Performance Photovoltaic Materials Based on the Superlattice Structures of Organic-Inorganic Halide Perovskite and Superhalogen Hybrid Perovskite. J Phys Chem Lett 2020; 11:5282-5294. [PMID: 32531164 DOI: 10.1021/acs.jpclett.0c01161] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The use of superlattice structures is an attractive strategy for expanding the family of perovskites and obtaining excellent optoelectronic materials. Mixing of cations and partial replacement of halogens by superhalogens are advantageous for improving the stability and optoelectronic properties of hybrid perovskites. Herein, the superlattice structures of the (CsPbI3)n/MAPbI2BF4, (FAPbI3)n/MAPbI2BF4, (MAPbI3)n/CsPbI2BF4, and (FAPbI3)n/CsPbI2BF4 hybrid perovskites were investigated using first-principles density functional theory calculations. The results show that these superlattice structures have tunable direct band gaps and small effective electron and hole masses. Additionally, the charge densities for the valence band maximum and conduction band minimum states are located in different regions of the superlattices. Suggesting that these structures are type-II superlattices that show greatly reduced electron-hole recombination rates. Excellent optical absorption properties for all of perovskite superlattices and the calculated power conversion efficiency of 22.77% for the single-junction solar cells based on the (FAPbI3)3/MAPbI2BF4 and (FAPbI3)3/CsPbI2BF4 perovskites were obtained.
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Affiliation(s)
- Dong Li
- Department of Physics, Beijing Jiaotong University, Beijing 100044, China
| | - Dan Li
- Department of Physics, Beijing Jiaotong University, Beijing 100044, China
| | - He Zhang
- Department of Physics, Beijing Jiaotong University, Beijing 100044, China
| | - Anqi Yang
- Department of Physics, Beijing Jiaotong University, Beijing 100044, China
| | - Chunjun Liang
- Key Laboratory of Luminescence and Optical Information, Ministry of Education, Beijing Jiaotong University, Beijing 100044, China
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48
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Meggiolaro D, Ricciarelli D, Alasmari AA, Alasmary FAS, De Angelis F. Tin versus Lead Redox Chemistry Modulates Charge Trapping and Self-Doping in Tin/Lead Iodide Perovskites. J Phys Chem Lett 2020; 11:3546-3556. [PMID: 32298590 DOI: 10.1021/acs.jpclett.0c00725] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Tin halide perovskites make up the only lead-free material class endowed with optoelectronic properties comparable to those of lead iodide perovskites. Despite significant progress, the device efficiency and stability of tin halide perovskites are still limited by two potentially related phenomena, i.e., self-p-doping and tin oxidation. Both processes are likely related to defects; thus, understanding tin halide defect chemistry is a key step toward exploitation of this class of materials. We investigate the MASnI3 perovskite defect chemistry, as a prototype of the entire materials class, using state-of-the-art density functional theory simulations. We show that the inherently low ionization potential of MASnI3 is solely responsible of the high stability of tin vacancy and interstitial iodine defects, which are in turn at the origin of the material p-doping. Tin vacancies create a locally iodine-rich environment that could promote Sn(II) → Sn(IV) oxidation. The higher band edge energies of MASnI3 compared to those of MAPbI3 lead to the emergence of deep electron traps associated with undercoordinated tin defects (e.g., interstitial tin) and the suppression of deep transitions associated with undercoordinated iodine defects that are typical of MAPbI3. Thus, while lead iodide perovskites are dominated by iodine chemistry, tin chemistry dominates tin iodide perovskite defect chemistry. Mixed tin/lead perovskites exhibit an intermediate behavior and are predicted to be potentially free of deep traps. Compositional alloying with different metals is finally explored as a strategy for mitigating defect formation and self-p-doping in tin iodide perovskites.
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Affiliation(s)
- Daniele Meggiolaro
- Computational Laboratory for Hybrid/Organic Photovoltaics (CLHYO), Istituto CNR di Scienze e Tecnologie Chimiche "Giulio Natta"(CNR-SCITEC), Via Elce di Sotto 8, 06123 Perugia, Italy
| | - Damiano Ricciarelli
- Computational Laboratory for Hybrid/Organic Photovoltaics (CLHYO), Istituto CNR di Scienze e Tecnologie Chimiche "Giulio Natta"(CNR-SCITEC), Via Elce di Sotto 8, 06123 Perugia, Italy
- Department of Chemistry, Biology and Biotechnology, University of Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy
| | - Ahmed A Alasmari
- The First Industrial Institute, TVTC, Riyadh 11451, Saudi Arabia
- Physics and Astronomy Department, College of Science, King Saud University, Riyadh 11451, Saudi Arabia
| | - Fatmah A S Alasmary
- Chemistry Department, College of Science, King Saud University, Riyadh 11451, Saudi Arabia
| | - Filippo De Angelis
- Computational Laboratory for Hybrid/Organic Photovoltaics (CLHYO), Istituto CNR di Scienze e Tecnologie Chimiche "Giulio Natta"(CNR-SCITEC), Via Elce di Sotto 8, 06123 Perugia, Italy
- Department of Chemistry, Biology and Biotechnology, University of Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy
- Chemistry Department, College of Science, King Saud University, Riyadh 11451, Saudi Arabia
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49
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Minimizing Defect States in Lead Halide Perovskite Solar Cell Materials. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10093061] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In order to reach the theoretical efficiency limits of lead-based metal halide perovskite solar cells, the voltage should be enhanced because it suffers from non-radiative recombination. Perovskite materials contain intrinsic defects that can act as Shockley–Read–Hall recombination centers. Several experimental and computational studies have characterized such defect states within the band gap. We give a systematic overview of compositional engineering by distinguishing the different defect-reducing mechanisms. Doping effects are divided into influences on: (1) crystallization; (2) lattice properties. Incorporation of dopant influences the lattice properties by: (a) lattice strain relaxation; (b) chemical bonding enhancement; (c) band gap tuning. The intrinsic lattice strain in undoped perovskite was shown to induce vacancy formation. The incorporation of smaller ions, such as Cl, F and Cd, increases the energy for vacancy formation. Zn doping is reported to induce strain relaxation but also to enhance the chemical bonding. The combination of computational studies using (DFT) calculations quantifying and qualifying the defect-reducing propensities of different dopants with experimental studies is essential for a deeper understanding and unraveling insights, such as the dynamics of iodine vacancies and the photochemistry of the iodine interstitials, and can eventually lead to a more rational approach in the search for optimal photovoltaic materials.
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Nan G, Beljonne D, Zhang X, Quarti C. Organic Cations Protect Methylammonium Lead Iodide Perovskites against Small Exciton-Polaron Formation. J Phys Chem Lett 2020; 11:2983-2991. [PMID: 32227856 DOI: 10.1021/acs.jpclett.0c00673] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Working organic-inorganic lead halide perovskite-based devices are notoriously sensitive to surface and interface effects. Using a combination of density functional theory (DFT) and time-dependent DFT methods, we report a comprehensive study of the changes (with respect to the bulk) in geometric and electronic structures going on at the (001) surface of a (tetragonal phase) methylammonium lead iodide perovskite slab, in the dark and upon photoexcitation. The formation of a hydrogen bonding pattern between the -NH3 groups of the organic cations and the iodine atoms of the outer inorganic layout is found to critically contribute to the relative thermodynamic stability of slabs with varying surface compositions and terminations. Most importantly, our results show that the hydrogen bond locking effects induced by the MA groups tend to protect the external two-dimensional lattice against large local structural deformations, i.e., the formation of a small exciton-polaron, at variance with purely inorganic lead halide perovskites.
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Affiliation(s)
- Guangjun Nan
- Department of Physics, Zhejiang Normal University, Jinhua, Zhejiang 321004, P. R. China
| | - David Beljonne
- Laboratory for Chemistry of Novel Materials, University of Mons, Place du Parc 20, B-7000 Mons, Belgium
| | - Xu Zhang
- Department of Physics and Astronomy, California State University Northridge, Northridge, California 91330-8268, United States
| | - Claudio Quarti
- Laboratory for Chemistry of Novel Materials, University of Mons, Place du Parc 20, B-7000 Mons, Belgium
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