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Surface chemical heterogeneous distribution in over-lithiated Li 1+xCoO 2 electrodes. Nat Commun 2022; 13:6464. [PMID: 36309496 PMCID: PMC9617898 DOI: 10.1038/s41467-022-34161-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 10/17/2022] [Indexed: 11/25/2022] Open
Abstract
In commercial Li-ion batteries, the internal short circuits or over-lithiation often cause structural transformation in electrodes and may lead to safety risks. Herein, we investigate the over-discharged mechanism of LiCoO2/graphite pouch cells, especially spatially resolving the morphological, surface phase, and local electronic structure of LiCoO2 electrode. With synchrotron-based X-ray techniques and Raman mapping, together with spectroscopy simulations, we demonstrate that over-lithiation reaction is a surface effect, accompanied by Co reduction and surface structure transformation to Li2CoO2/Co3O4/CoO/Li2O-like phases. This surface chemical distribution variation is relevant to the depth and exposed crystalline planes of LiCoO2 particles, and the distribution of binder/conductive additives. Theoretical calculations confirm that Li2CoO2-phase has lower electronic/ionic conductivity than LiCoO2-phase, further revealing the critical effect of distribution of conductive additives on the surface chemical heterogeneity evolution. Our findings on such surface phenomena are non-trivial and highlight the capability of synchrotron-based X-ray techniques for studying the spatial chemical phase heterogeneity. Over-lithiation often causes structural transformation in electrodes and may lead to safety issues in Li-ion batteries. Here, authors investigate the over-discharged mechanism of LiCoO2/graphite pouch cells, and spatially resolve the morphological, surface phase, and local electronic structure of LiCoO2 electrode.
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García-Fernández A, Svanström S, Sterling CM, Gangan A, Erbing A, Kamal C, Sloboda T, Kammlander B, Man GJ, Rensmo H, Odelius M, Cappel UB. Experimental and Theoretical Core Level and Valence Band Analysis of Clean Perovskite Single Crystal Surfaces. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2106450. [PMID: 35122466 DOI: 10.1002/smll.202106450] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Indexed: 06/14/2023]
Abstract
A detailed understanding of the surface and interface properties of lead halide perovskites is of interest for several applications, in which these materials may be used. To develop this understanding, the study of clean crystalline surfaces can be an important stepping stone. In this work, the surface properties and electronic structure of two different perovskite single crystal compositions (MAPbI3 and Csx FA1- x PbI3 ) are investigated using synchrotron-based soft X-ray photoelectron spectroscopy (PES), molecular dynamics simulations, and density functional theory. The use of synchrotron-based soft X-ray PES enables high surface sensitivity and nondestructive depth-profiling. Core level and valence band spectra of the single crystals are presented. The authors find two carbon 1s contributions at the surface of MAPbI3 and assign these to MA+ ions in an MAI-terminated surface and to MA+ ions below the surface. It is estimated that the surface is predominantly MAI-terminated but up to 30% of the surface can be PbI2 -terminated. The results presented here can serve as reference spectra for photoelectron spectroscopy investigations of technologically relevant polycrystalline thin films, and the findings can be utilized to further optimize the design of device interfaces.
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Affiliation(s)
- Alberto García-Fernández
- Division of Applied Physical Chemistry, Department of Chemistry, KTH - Royal Institute of Technology, Stockholm, SE-100 44, Sweden
| | - Sebastian Svanström
- Condensed Matter Physics of Energy Materials, Division of X-ray Photon Science, Department of Physics and Astronomy, Uppsala University, Box 516, Uppsala, SE-751 20, Sweden
| | - Cody M Sterling
- Department of Physics, Stockholm University, AlbaNova University Center, Stockholm, 10691, Sweden
| | - Abhijeet Gangan
- Department of Physics, Stockholm University, AlbaNova University Center, Stockholm, 10691, Sweden
| | - Axel Erbing
- Department of Physics, Stockholm University, AlbaNova University Center, Stockholm, 10691, Sweden
| | - Chinnathambi Kamal
- Department of Physics, Stockholm University, AlbaNova University Center, Stockholm, 10691, Sweden
- Theory and Simulations Laboratory, HRDS, Raja Ramanna Centre for Advanced Technology, Indore, Madhya Pradesh, 452013, India
- Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai, Maharashtra, 400094, India
| | - Tamara Sloboda
- Division of Applied Physical Chemistry, Department of Chemistry, KTH - Royal Institute of Technology, Stockholm, SE-100 44, Sweden
| | - Birgit Kammlander
- Division of Applied Physical Chemistry, Department of Chemistry, KTH - Royal Institute of Technology, Stockholm, SE-100 44, Sweden
| | - Gabriel J Man
- Condensed Matter Physics of Energy Materials, Division of X-ray Photon Science, Department of Physics and Astronomy, Uppsala University, Box 516, Uppsala, SE-751 20, Sweden
| | - Håkan Rensmo
- Condensed Matter Physics of Energy Materials, Division of X-ray Photon Science, Department of Physics and Astronomy, Uppsala University, Box 516, Uppsala, SE-751 20, Sweden
| | - Michael Odelius
- Department of Physics, Stockholm University, AlbaNova University Center, Stockholm, 10691, Sweden
| | - Ute B Cappel
- Division of Applied Physical Chemistry, Department of Chemistry, KTH - Royal Institute of Technology, Stockholm, SE-100 44, Sweden
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Yue S, McGuire SC, Yan H, Chu YS, Cotlet M, Tong X, Wong SS. Synthesis, Characterization, and Stability Studies of Ge-Based Perovskites of Controllable Mixed Cation Composition, Produced with an Ambient Surfactant-Free Approach. ACS OMEGA 2019; 4:18219-18233. [PMID: 31720523 PMCID: PMC6844100 DOI: 10.1021/acsomega.9b02203] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 10/08/2019] [Indexed: 05/06/2023]
Abstract
In this report, we have applied a facile, ligand-free, ambient synthesis protocol toward the fabrication of not only a series of lead-free Ge-based perovskites with the general formulation of MA1-x FA x GeI3 (where x was changed from 0, 0.25, 0.5, 0.75, to 1) but also CsGeI3. Specifically, our methodology for producing ABX3 systems is generalizable, regardless of the identity of either the A site cation or the X site halide ion. Moreover, it incorporates many advantages, including (i) the possibility of efficiently generating pure Ge-based perovskite particles of any desired chemical composition, (ii) the use of readily available, commercial precursors and comparatively lower toxicity solvents, (iii) the practicality of scale up, and (iv) the elimination of the need for any superfluous organic surface ligands or surfactants. In addition to providing mechanistic insights into their formation, we have examined the chemical composition, crystallite size, morphology, surface attributes, oxidation states, and optical properties of our as-prepared perovskites using a combination of diffraction, microscopy, and spectroscopy techniques. Specifically, we noted that the optical band gap could be reliably tuned as a function of chemical composition, via the identity of the A site cation. Moreover, we have probed their stability, not only under standard storage conditions but also, for the first time, when subjected to both e-beam- and X-ray-induced degradation, using cumulative data from sources such as synchrotron-based scanning hard X-ray microscopy. Importantly, of relevance for the potential practical incorporation of these Pb-free perovskites, our work has emphasized the possibility of controlling the chemical composition within Ge-based perovskites as a means of rationally tuning their observed band gaps and optical behavior.
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Affiliation(s)
- Shiyu Yue
- Department of Chemistry, State University of New York at Stony Brook, Stony Brook, New York 11794-3400, United States
| | - Scott C. McGuire
- Department of Chemistry, State University of New York at Stony Brook, Stony Brook, New York 11794-3400, United States
| | - Hanfei Yan
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Yong S. Chu
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Mircea Cotlet
- Center for Functional Nanomaterials, Brookhaven
National Laboratory, Building 735, Upton, New York 11973, United States
| | - Xiao Tong
- Center for Functional Nanomaterials, Brookhaven
National Laboratory, Building 735, Upton, New York 11973, United States
| | - Stanislaus S. Wong
- Department of Chemistry, State University of New York at Stony Brook, Stony Brook, New York 11794-3400, United States
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4
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Yu X, Yan H, Peng Q. Reaction Temperature and Partial Pressure Induced Etching of Methylammonium Lead Iodide Perovskite by Trimethylaluminum. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:6522-6531. [PMID: 31035746 DOI: 10.1021/acs.langmuir.8b01419] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Al2O3 atomic layer deposition (ALD), which uses trimethylaluminum (TMA) as the metal precursor, shows promise in improving the environmental stability of hybrid halide perovskites. However, it is not yet entirely clear how TMA, a strong Lewis acid, reacts with fresh perovskites and how the reaction affects the nucleation of ALD Al2O3. Here, the effects of reaction temperature and partial pressure of TMA on the mechanisms of TMA/CH3NH3PbI3 reactions are investigated. Our real time mass gain data and in situ mass spectrometry data show that the TMA/CH3NH3PbI3 reaction can either remove mass or accumulate mass onto CH3NH3PbI3 substrates, depending strongly on the reaction temperature and partial pressure of TMA. The TMA/CH3NH3PbI3 reaction probably generates TMA-CH3NHx adduct compounds, which protects CH3NH3PbI3 from TMA by forming a shell at 25 °C in the vacuum process. However, these adduct compounds decompose at higher temperatures (e.g., 75 °C). This product layer is much thicker than a monolayer, suggesting the interface formed between Al2O3 coating and CH3NH3PbI3 is blurring and messy. These results have not yet, but should be, carefully considered to correctly interpret the effect of ALD Al2O3 treatment on optoelectronic properties of CH3NH3PbI3.
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Affiliation(s)
- Xiaozhou Yu
- Chemical and Biological Engineering Department , University of Alabama , P.O. Box 870203, Tuscaloosa , Alabama 35487 , United States
| | - Haoming Yan
- Chemical and Biological Engineering Department , University of Alabama , P.O. Box 870203, Tuscaloosa , Alabama 35487 , United States
| | - Qing Peng
- Chemical and Biological Engineering Department , University of Alabama , P.O. Box 870203, Tuscaloosa , Alabama 35487 , United States
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Juarez-Perez EJ, Ono LK, Uriarte I, Cocinero EJ, Qi Y. Degradation Mechanism and Relative Stability of Methylammonium Halide Based Perovskites Analyzed on the Basis of Acid-Base Theory. ACS APPLIED MATERIALS & INTERFACES 2019; 11:12586-12593. [PMID: 30848116 DOI: 10.1021/acsami.9b02374] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The correct identification of all gases released during hybrid perovskite degradation is of great significance to develop strategies to extend the lifespan of any device based on this semiconductor. CH3X (X = Br/I) is a released degradation gas/low boiling point liquid arising from methylammonium (MA+) based perovskites, which has been largely overlooked in the literature focusing on stability of perovskite solar cells. Herein, we present an unambiguous identification of CH3I release using microwave (rotational) spectroscopy. An experimental back-reaction test demonstrates that the well-known CH3NH2/HX degradation route may not be the ultimate degradation pathway of MAPbX3 in thermodynamic closed systems. Meanwhile, the CH3X/NH3 route cannot back-react selectively to MAX formation as occurred for the former back-reaction. Metadynamics calculations uncover the X halide effect on energy barriers for both degradation reactions showing a better stability of Br based perovskite ascribed to two aspects: (i) lower Brönsted-Lowry acidity of HBr compared to HI and (ii) higher nucleophilic character of CH3NH2 compared to NH3. The latter property makes CH3NH2 molecules stay preferentially attached on the electrophilic perovskite surface (Pb2+) during the dynamic simulation instead of being detached as observed for the NH3 molecule.
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Affiliation(s)
- Emilio J Juarez-Perez
- Energy Materials and Surface Sciences Unit (EMSSU) , Okinawa Institute of Science and Technology Graduate University (OIST) , 1919-1 Tancha , Onna-son , Okinawa 904-0495 , Japan
| | - Luis K Ono
- Energy Materials and Surface Sciences Unit (EMSSU) , Okinawa Institute of Science and Technology Graduate University (OIST) , 1919-1 Tancha , Onna-son , Okinawa 904-0495 , Japan
| | - Iciar Uriarte
- Departamento de Química Física, Facultad de Ciencia y Tecnología , Universidad del País Vasco (UPV/EHU) , Barrio Sarriena , 48940 Leioa , Spain
- Biofisika Institute (CSIC, UPV/EHU) , Universidad del País Vasco (UPV/EHU) , Apartado 644 , E-48080 Bilbao , Spain
| | - Emilio J Cocinero
- Departamento de Química Física, Facultad de Ciencia y Tecnología , Universidad del País Vasco (UPV/EHU) , Barrio Sarriena , 48940 Leioa , Spain
- Biofisika Institute (CSIC, UPV/EHU) , Universidad del País Vasco (UPV/EHU) , Apartado 644 , E-48080 Bilbao , Spain
| | - Yabing Qi
- Energy Materials and Surface Sciences Unit (EMSSU) , Okinawa Institute of Science and Technology Graduate University (OIST) , 1919-1 Tancha , Onna-son , Okinawa 904-0495 , Japan
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6
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McLeod JA, Liu L. Prospects for Mitigating Intrinsic Organic Decomposition in Methylammonium Lead Triiodide Perovskite. J Phys Chem Lett 2018; 9:2411-2417. [PMID: 29672059 DOI: 10.1021/acs.jpclett.8b00323] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Organometallic lead halide perovskites seem to be on the threshold of becoming viable commercial photovoltaics; however, further improvements to the stability of these materials must be made before they can compete with existing photovoltaic technologies. Of the organometallic lead halide perovskites used in photovoltaics, methylammonium lead triiodide perovskite (MAPI) is perhaps the most studied, and understanding how MAPI degrades is crucial for developing strategies to improve stability. We discuss the experimental evidence behind several possible routes for MAPI to degrade into PbI2 and various organics, and how the decomposition path of MAPI may strongly depend on substrate, precursors, intrinsic organic defects, and morphology. Exploring the conditions required for MAPI to degrade according to a particular pathway is important not only from a fundamental materials chemistry perspective, but also for understanding intrinsic instability in MAPI-based photovoltaics and to develop strategies to improve stability.
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Affiliation(s)
- John A McLeod
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano and Soft Materials (FUNSOM), Joint International Research Laboratory of Carbon-Based Functional Materials and Devices , Soochow University , Suzhou , Jiangsu 215123 China
| | - Lijia Liu
- Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Institute of Functional Nano and Soft Materials (FUNSOM), Joint International Research Laboratory of Carbon-Based Functional Materials and Devices , Soochow University , Suzhou , Jiangsu 215123 China
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7
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Investigation of Thermally Induced Degradation in CH 3NH 3PbI 3 Perovskite Solar Cells using In-situ Synchrotron Radiation Analysis. Sci Rep 2017; 7:4645. [PMID: 28680138 PMCID: PMC5498566 DOI: 10.1038/s41598-017-04690-w] [Citation(s) in RCA: 143] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 05/18/2017] [Indexed: 11/13/2022] Open
Abstract
In this study, we employ a combination of various in-situ surface analysis techniques to investigate the thermally induced degradation processes in MAPbI3 perovskite solar cells (PeSCs) as a function of temperature under air-free conditions (no moisture and oxygen). Through a comprehensive approach that combines in-situ grazing-incidence wide-angle X-ray diffraction (GIWAXD) and high-resolution X-ray photoelectron spectroscopy (HR-XPS) measurements, we confirm that the surface structure of MAPbI3 perovskite film changes to an intermediate phase and decomposes to CH3I, NH3, and PbI2 after both a short (20 min) exposure to heat stress at 100 °C and a long exposure (>1 hour) at 80 °C. Moreover, we observe clearly the changes in the orientation of CH3NH3+ organic cations with respect to the substrate in the intermediate phase, which might be linked directly to the thermal degradation processes in MAPbI3 perovskites. These results provide important progress towards improved understanding of the thermal degradation mechanisms in perovskite materials and will facilitate improvements in the design and fabrication of perovskite solar cells with better thermal stability.
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Sarmah SP, Burlakov VM, Yengel E, Murali B, Alarousu E, El-Zohry AM, Yang C, Alias MS, Zhumekenov AA, Saidaminov MI, Cho N, Wehbe N, Mitra S, Ajia I, Dey S, Mansour AE, Abdelsamie M, Amassian A, Roqan IS, Ooi BS, Goriely A, Bakr OM, Mohammed OF. Double Charged Surface Layers in Lead Halide Perovskite Crystals. NANO LETTERS 2017; 17:2021-2027. [PMID: 28145714 DOI: 10.1021/acs.nanolett.7b00031] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Understanding defect chemistry, particularly ion migration, and its significant effect on the surface's optical and electronic properties is one of the major challenges impeding the development of hybrid perovskite-based devices. Here, using both experimental and theoretical approaches, we demonstrated that the surface layers of the perovskite crystals may acquire a high concentration of positively charged vacancies with the complementary negatively charged halide ions pushed to the surface. This charge separation near the surface generates an electric field that can induce an increase of optical band gap in the surface layers relative to the bulk. We found that the charge separation, electric field, and the amplitude of shift in the bandgap strongly depend on the halides and organic moieties of perovskite crystals. Our findings reveal the peculiarity of surface effects that are currently limiting the applications of perovskite crystals and more importantly explain their origins, thus enabling viable surface passivation strategies to remediate them.
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Affiliation(s)
| | - Victor M Burlakov
- Mathematical Institute, University of Oxford , Woodstock Road, Oxford OX2 6GG, United Kingdom
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Alain Goriely
- Mathematical Institute, University of Oxford , Woodstock Road, Oxford OX2 6GG, United Kingdom
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Wang R, Wu C, Hu Y, Li J, Shen P, Wang Q, Liao L, Liu L, Duhm S. CH 3NH 3PbI 3-xCl x under Different Fabrication Strategies: Electronic Structures and Energy-Level Alignment with an Organic Hole Transport Material. ACS APPLIED MATERIALS & INTERFACES 2017; 9:7859-7865. [PMID: 28185450 DOI: 10.1021/acsami.7b00312] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We report a photoelectron spectroscopy study on the electronic structure of CH3NH3PbI3-xClx thin films fabricated by physical evaporation from CH3NH3I and PbCl2 precursors, including (1) simultaneously evaporation and (2) sequential evaporation. The results are compared with CH3NH3PbI3-xClx made using conventional solution chemistry (i.e., spin-coating). Depending on the fabrication method, CH3NH3PbI3-xClx films show different chemical constituents in the near-surface region, leading to disparities in their energetic levels. The chemical identities of the surface species are revealed by an in situ study on the sequentially evaporated film. Moreover, air-exposure treatment also greatly alters the energetic levels of the film. Using hole transport layer of N,N'-di(1-naphthyl)-N,N'-diphenylbenzidine (NPB) as a model system, we find that the energy-level alignment with the spin-coated film after air exposure is most suitable for efficient hole transport.
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Affiliation(s)
- Rongbin Wang
- Jiangsu Key Laboratory for Carbon-based Functional Materials and Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University , 199 Ren'ai Road, Suzhou, Jiangsu 215123, China
- Institut für Physik, Humboldt-Universität zu Berlin , Brook-Taylor Straße 6, 12489 Berlin, Germany
| | - Chen Wu
- Jiangsu Key Laboratory for Carbon-based Functional Materials and Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University , 199 Ren'ai Road, Suzhou, Jiangsu 215123, China
| | - Yun Hu
- Jiangsu Key Laboratory for Carbon-based Functional Materials and Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University , 199 Ren'ai Road, Suzhou, Jiangsu 215123, China
| | - Jitao Li
- Jiangsu Key Laboratory for Carbon-based Functional Materials and Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University , 199 Ren'ai Road, Suzhou, Jiangsu 215123, China
| | - Pengfei Shen
- Jiangsu Key Laboratory for Carbon-based Functional Materials and Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University , 199 Ren'ai Road, Suzhou, Jiangsu 215123, China
| | - Qi Wang
- Jiangsu Key Laboratory for Carbon-based Functional Materials and Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University , 199 Ren'ai Road, Suzhou, Jiangsu 215123, China
| | - Liangsheng Liao
- Jiangsu Key Laboratory for Carbon-based Functional Materials and Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University , 199 Ren'ai Road, Suzhou, Jiangsu 215123, China
| | - Lijia Liu
- Jiangsu Key Laboratory for Carbon-based Functional Materials and Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University , 199 Ren'ai Road, Suzhou, Jiangsu 215123, China
| | - Steffen Duhm
- Jiangsu Key Laboratory for Carbon-based Functional Materials and Devices, Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University , 199 Ren'ai Road, Suzhou, Jiangsu 215123, China
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Paduani C, Rappe AM. Tuning the gap of lead-based halide perovskites by introducing superalkali species at the cationic sites of ABX3-type structure. Phys Chem Chem Phys 2017; 19:20619-20626. [DOI: 10.1039/c7cp02091k] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
New perovskites are formed by introducing polyatomic yet aprotic superalkali species at the cationic A-sites of the ABX3 structure.
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Affiliation(s)
- C. Paduani
- Department of Chemistry
- University of Pennsylvania
- Philadelphia
- USA
| | - Andrew M. Rappe
- Department of Chemistry
- University of Pennsylvania
- Philadelphia
- USA
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11
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Ono LK, Qi Y. Surface and Interface Aspects of Organometal Halide Perovskite Materials and Solar Cells. J Phys Chem Lett 2016; 7:4764-4794. [PMID: 27791377 DOI: 10.1021/acs.jpclett.6b01951] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The current challenges (e.g., stability, hysteresis, etc.) in organometal halide perovskite solar cell research are closely correlated with surfaces and interfaces. For instance, efficient generation of charges, extraction, and transport with minimum recombination through interlayer interfaces is crucial to attain high-efficiency solar cell devices. Furthermore, intralayer interfaces may be present in the form of grain boundaries within a film composed of the same material, for example, a polycrystalline perovskite layer. The adjacent grains may assume different crystal orientations and/or have different chemical compositions, which impacts charge excitation and dynamics and thereby the overall solar cell performance. In this Perspective, we present case studies to demonstrate (1) how surfaces and interfaces can impact material properties and device performance and (2) how these issues can be investigated by surface science techniques, such as scanning probe microscopy, photoelectron spectroscopy, and so forth. We end this Perspective by outlining the future research directions based on the reported results as well as the new trends in the field.
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Affiliation(s)
- Luis K Ono
- Energy Materials and Surface Sciences Unit (EMSS), Okinawa Institute of Science and Technology Graduate University (OIST) , 1919-1 Tancha, Onna-son, Okinawa 904-0495, Japan
| | - Yabing Qi
- Energy Materials and Surface Sciences Unit (EMSS), Okinawa Institute of Science and Technology Graduate University (OIST) , 1919-1 Tancha, Onna-son, Okinawa 904-0495, Japan
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