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Park J, Huh S, Choi YW, Kang D, Kim M, Kim D, Park S, Choi HJ, Kim C, Yi Y. Visualizing the Low-Energy Electronic Structure of Prototypical Hybrid Halide Perovskite through Clear Band Measurements. ACS NANO 2024; 18:7570-7579. [PMID: 38377437 DOI: 10.1021/acsnano.3c12587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2024]
Abstract
Organic-inorganic hybrid perovskites (OIHPs) are a promising class of materials that rival conventional semiconductors in various optoelectronic applications. However, unraveling the precise nature of their low-energy electronic structures continues to pose a significant challenge, primarily due to the absence of clear band measurements. Here, we investigate the low-energy electronic structure of CH3NH3PbI3 (MAPI3) using angle-resolved photoelectron spectroscopy combined with ab initio density functional theory. We successfully visualize the electronic structure of MAPI3 near the bulk valence band maximum by using a laboratory photon source (He Iα, 21.2 eV) at low temperature and explore its fundamental properties. The observed valence band exhibits a highly isotropic and parabolic band characterized by small effective masses of 0.20-0.21 me, without notable spectral signatures associated with a large polaron or the Rashba effect, subjects that are intensely debated in the literature. Concurrently, our spin-resolved measurements directly disprove the giant Rashba scenario previously suggested in a similar perovskite compound by establishing an upper limit for the Rashba parameter (αR) of 0.28 eV Å. Our results unveil the unusually complex nature of the low-energy electronic structure of OIHPs, thereby advancing our fundamental understanding of this important class of materials.
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Affiliation(s)
- Jeehong Park
- Department of Physics, Yonsei University, Seoul 03722, Republic of Korea
- Van der Waals Materials Research Center, Yonsei University, Seoul 03722, Republic of Korea
| | - Soonsang Huh
- Department of Physics, Yonsei University, Seoul 03722, Republic of Korea
- Center for Correlated Electron System, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea
| | - Young Woo Choi
- Department of Physics, Yonsei University, Seoul 03722, Republic of Korea
- Van der Waals Materials Research Center, Yonsei University, Seoul 03722, Republic of Korea
| | - Donghee Kang
- Department of Physics, Yonsei University, Seoul 03722, Republic of Korea
- Van der Waals Materials Research Center, Yonsei University, Seoul 03722, Republic of Korea
| | - Minsoo Kim
- Center for Correlated Electron System, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea
- Department of Physics and Astronomy, Seoul National University (SNU), Seoul 08826, Republic of Korea
| | - Donghan Kim
- Center for Correlated Electron System, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea
- Department of Physics and Astronomy, Seoul National University (SNU), Seoul 08826, Republic of Korea
| | - Soohyung Park
- Advanced Analysis Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Hyoung Joon Choi
- Department of Physics, Yonsei University, Seoul 03722, Republic of Korea
- Van der Waals Materials Research Center, Yonsei University, Seoul 03722, Republic of Korea
| | - Changyoung Kim
- Center for Correlated Electron System, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea
- Department of Physics and Astronomy, Seoul National University (SNU), Seoul 08826, Republic of Korea
| | - Yeonjin Yi
- Department of Physics, Yonsei University, Seoul 03722, Republic of Korea
- Van der Waals Materials Research Center, Yonsei University, Seoul 03722, Republic of Korea
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2
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Kumar D, Bansal NK, Dixit H, Kulkarni A, Singh T. Numerical Study on the Effect of Dual Electron Transport Layer in Improving the Performance of Perovskite–Perovskite Tandem Solar Cells. ADVANCED THEORY AND SIMULATIONS 2023. [DOI: 10.1002/adts.202200800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Dinesh Kumar
- Functional Materials and Device Laboratory School of Energy Science and Engineering Indian Institute of Technology Kharagpur Kharagpur West Bengal 721302 India
| | - Nitin Kumar Bansal
- Functional Materials and Device Laboratory School of Energy Science and Engineering Indian Institute of Technology Kharagpur Kharagpur West Bengal 721302 India
| | - Himanshu Dixit
- Functional Materials and Device Laboratory School of Energy Science and Engineering Indian Institute of Technology Kharagpur Kharagpur West Bengal 721302 India
| | - Ashish Kulkarni
- IEK‐5 Photovoltaik Forschungszentrum Jülich Wilhelm‐Johnen‐Straße 52428 Jülich Germany
| | - Trilok Singh
- Functional Materials and Device Laboratory School of Energy Science and Engineering Indian Institute of Technology Kharagpur Kharagpur West Bengal 721302 India
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3
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Zu F, Warby JH, Stolterfoht M, Li J, Shin D, Unger E, Koch N. Photoinduced Energy-Level Realignment at Interfaces between Organic Semiconductors and Metal-Halide Perovskites. PHYSICAL REVIEW LETTERS 2021; 127:246401. [PMID: 34951794 DOI: 10.1103/physrevlett.127.246401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 06/19/2021] [Accepted: 11/02/2021] [Indexed: 06/14/2023]
Abstract
In contrast to the common conception that the interfacial energy-level alignment is affixed once the interface is formed, we demonstrate that heterojunctions between organic semiconductors and metal-halide perovskites exhibit huge energy-level realignment during photoexcitation. Importantly, the photoinduced level shifts occur in the organic component, including the first molecular layer in direct contact with the perovskite. This is caused by charge-carrier accumulation within the organic semiconductor under illumination and the weak electronic coupling between the junction components.
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Affiliation(s)
- Fengshuo Zu
- Institut für Physik & IRIS Adlershof, Humboldt-Universität zu Berlin, 12489 Berlin, Germany
| | - Jonathan H Warby
- Institut für Physik und Astronomie, Universität Potsdam, 14776 Potsdam, Germany
| | - Martin Stolterfoht
- Institut für Physik und Astronomie, Universität Potsdam, 14776 Potsdam, Germany
| | - Jinzhao Li
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, 12489 Berlin, Germany
| | - Dongguen Shin
- Institut für Physik & IRIS Adlershof, Humboldt-Universität zu Berlin, 12489 Berlin, Germany
| | - Eva Unger
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, 12489 Berlin, Germany
| | - Norbert Koch
- Institut für Physik & IRIS Adlershof, Humboldt-Universität zu Berlin, 12489 Berlin, Germany
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, 12489 Berlin, Germany
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Yang JP, Yang MF, Tang GB, Kera S. Density of gap states in CH 3NH 3PbI 3single crystals probed with ultrahigh-sensitivity ultraviolet photoelectron spectroscopy. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:475001. [PMID: 34469875 DOI: 10.1088/1361-648x/ac22da] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 09/01/2021] [Indexed: 06/13/2023]
Abstract
The advantages of methylammonium triiodideplumbate (CH3NH3PbI3)-based organic-inorganic hybrid halide perovskite have led to devices with power conversion efficiencies of >20%. The CH3NH3PbI3structure is prone to be more sensitive towards external effects due to its higher flexibility than inorganic counterparts. Nevertheless, a direct photoemission spectroscopy study is still lacking on the density of gap states (DOGS) influenced by air exposure and synchrotron light-induced degradation. In this paper, we investigate the evolution of electronic structure in CH3NH3PbI3single crystals after air exposure and intense synchrotron light irradiation to reveal the effects on its density of states distribution below and above the valence band maximum (VBM) by using ultrahigh-sensitivity photoelectron spectroscopy. We find that the PbI2compounds, decomposed from CH3NH3PbI3after air exposure, could not affect the DOGS distribution but only give the VBM shift in the high binding energy region, which is dramatically different from the impacts of an impurity found for other organic or inorganic counterparts. A further study using intense synchrotron irradiation confirms the decomposed processes for CH3NH3PbI3: (i) the initial degradation would induce the formation of PbI2, which gives a negligible impact on the DOGS above the VBM; (ii) the continuous intense light irradiation could further degrade PbI2to metallic Pb, in which DOGS appears in the energy bandgap.
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Affiliation(s)
- Jin-Peng Yang
- College of Physical Science and Technology & Institute of Optoelectronic Technology, Yangzhou University, 225009, People's Republic of China
| | - Meng-Fan Yang
- College of Physical Science and Technology & Institute of Optoelectronic Technology, Yangzhou University, 225009, People's Republic of China
| | - Gong-Bin Tang
- Institute of Novel Semiconductors, Shandong University, 250100, People's Republic of China
| | - Satoshi Kera
- Institute for Molecular Science, Department of Photo-Molecular Science, Myodaiji, Okazaki 444-8585, Japan
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Shin D, Zu F, Cohen AV, Yi Y, Kronik L, Koch N. Mechanism and Timescales of Reversible p-Doping of Methylammonium Lead Triiodide by Oxygen. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2100211. [PMID: 33938045 PMCID: PMC11468336 DOI: 10.1002/adma.202100211] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Revised: 03/05/2021] [Indexed: 06/12/2023]
Abstract
Understanding and controlling the energy level alignment at interfaces with metal halide perovskites (MHPs) is essential for realizing the full potential of these materials for use in optoelectronic devices. To date, however, the basic electronic properties of MHPs are still under debate. Particularly, reported Fermi level positions in the energy gap vary from indicating strong n- to strong p-type character for nominally identical materials, raising serious questions about intrinsic and extrinsic defects as dopants. In this work, photoemission experiments demonstrate that thin films of the prototypical methylammonium lead triiodide (MAPbI3 ) behave like an intrinsic semiconductor in the absence of oxygen. Oxygen is then shown to be able to reversibly diffuse into and out of the MAPbI3 bulk, requiring rather long saturation timescales of ≈1 h (in: ambient air) and over 10 h (out: ultrahigh vacuum), for few 100 nm thick films. Oxygen in the bulk leads to pronounced p-doping, positioning the Fermi level universally ≈0.55 eV above the valence band maximum. The key doping mechanism is suggested to be molecular oxygen substitution of iodine vacancies, supported by density functional theory calculations. This insight rationalizes previous and future electronic property studies of MHPs and calls for meticulous oxygen exposure protocols.
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Affiliation(s)
- Dongguen Shin
- Institut für Physik & IRIS AdlershofHumboldt‐Universität zu Berlin12489BerlinGermany
- Helmholtz‐Zentrum Berlin für Materialien und Energie GmbH12489BerlinGermany
| | - Fengshuo Zu
- Institut für Physik & IRIS AdlershofHumboldt‐Universität zu Berlin12489BerlinGermany
| | - Ayala V. Cohen
- Department of Molecular Chemistry and Materials ScienceWeizmann Institute of ScienceRehovoth76100Israel
| | - Yeonjin Yi
- Institute of Physics and Applied Physics & Van der Waals Materials Research CenterYonsei UniversitySeoul03722Republic of Korea
| | - Leeor Kronik
- Department of Molecular Chemistry and Materials ScienceWeizmann Institute of ScienceRehovoth76100Israel
| | - Norbert Koch
- Institut für Physik & IRIS AdlershofHumboldt‐Universität zu Berlin12489BerlinGermany
- Helmholtz‐Zentrum Berlin für Materialien und Energie GmbH12489BerlinGermany
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Mirzehmet A, Ohtsuka T, Abd Rahman SA, Yuyama T, Krüger P, Yoshida H. Surface Termination of Solution-Processed CH 3NH 3PbI 3 Perovskite Film Examined using Electron Spectroscopies. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2004981. [PMID: 33617084 DOI: 10.1002/adma.202004981] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 10/19/2020] [Indexed: 05/21/2023]
Abstract
The interfaces of a perovskite solar cell significantly influence the charge processes in the cell, which contributes to the device performance with direct implication for surface potential, electronic structure, and chemical reactivity. The properties of the interface are strongly affected by the surface termination. In this work, the combination of ultraviolet photoelectron spectroscopy (UPS) and metastable-atom electron spectroscopy is demonstrated, to examine the surface termination of a solution-processed CH3NH3PbI3 perovskite film. The results show that the surface of the CH3NH3PbI3 perovskite film is terminated with a layer consisting of CH3NH3 and I. The interface energy level alignment for both occupied and unoccupied levels between CH3NH3PbI3 and C60 is also examined using UPS and low-energy inverse photoelectron spectroscopy. It turns out that an ideal energy level alignment is established for the electron collection and hole block at the perovskite and C60 interface.
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Affiliation(s)
- Abduheber Mirzehmet
- Graduate School of Advanced Integration Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
| | - Tomoki Ohtsuka
- Graduate School of Science and Engineering, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
| | - Syed A Abd Rahman
- Graduate School of Science and Engineering, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
| | - Tomoki Yuyama
- Graduate School of Science and Engineering, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
| | - Peter Krüger
- Graduate School of Engineering, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
- Molecular Chirality Research Center, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
| | - Hiroyuki Yoshida
- Graduate School of Engineering, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
- Molecular Chirality Research Center, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, 263-8522, Japan
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Boehm AM, Liu T, Park SM, Abtahi A, Graham KR. Influence of Surface Ligands on Energetics at FASnI 3/C 60 Interfaces and Their Impact on Photovoltaic Performance. ACS APPLIED MATERIALS & INTERFACES 2020; 12:5209-5218. [PMID: 31887000 DOI: 10.1021/acsami.9b17535] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Interfacial chemistry and energetics significantly impact the performance of photovoltaic devices. In the case of Pb-containing organic metal halide perovskites, photoelectron spectroscopy has been used to determine the energetic alignment of frontier electronic energy levels at various interfaces present in the photovoltaic device. For the Sn-containing analogues, which are less toxic, no such measurements have been made. Through a combination of ultraviolet, inverse, and X-ray photoelectron spectroscopy (UPS, IPES, and XPS, respectively) measurements taken at varying thickness increments during stepwise deposition of C60 on FASnI3, we present the first direct measurements of the frontier electronic energy levels across the FASnI3/C60 interface. The results show band bending in both materials and transport gap widening in FASnI3 at the interface with C60. The XPS results show that iodide diffuses into C60 and results in n-doping of C60. This iodide diffusion out of FASnI3 impacts the valence and conduction band energies of FASnI3 more than the core levels, with the core level shifts displaying a different trend than the valence and conduction bands. Surface treatment of FASnI3 with carboxylic acids and bulky ammonium substituted surface ligands results in slight alterations in the interfacial energetics, and all surface ligands result in similar or improved PV performance relative to the untreated devices. The greatest PV stability results from treatment with a fluorinated carboxylic acid derivative; however, iodide diffusion is still observed to occur with this surface ligand.
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Affiliation(s)
- Alex M Boehm
- Department of Chemistry , University of Kentucky , Lexington , Kentucky 40506 , United States
| | - Tuo Liu
- Department of Chemistry , University of Kentucky , Lexington , Kentucky 40506 , United States
| | - So Min Park
- Department of Chemistry , University of Kentucky , Lexington , Kentucky 40506 , United States
- Department of Chemical and Materials Engineering , University of Kentucky , Lexington , Kentucky 40506 , United States
| | - Ashkan Abtahi
- Department of Chemistry , University of Kentucky , Lexington , Kentucky 40506 , United States
- Department of Physics and Astronomy , University of Kentucky , Lexington , Kentucky 40506 , United States
| | - Kenneth R Graham
- Department of Chemistry , University of Kentucky , Lexington , Kentucky 40506 , United States
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Jang J, Choe G, Yim S. Effective Control of Chlorine Contents in MAPbI 3- xCl x Perovskite Solar Cells Using a Single-Source Vapor Deposition and Anion-Exchange Technique. ACS APPLIED MATERIALS & INTERFACES 2019; 11:20073-20081. [PMID: 31091870 DOI: 10.1021/acsami.9b05101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In this study, a new method is developed to control the Cl-to-I ratio in MAPbI3- xCl x perovskite solar cells (PSCs) more easily and precisely using single-source vapor deposition of MAPbCl3 thin films and a subsequent anion exchange by repeated spin-coatings of methylammonium iodide (MAI) solution. This method can overcome the problems of previous vapor-deposition techniques for PSCs such as the occurrence of morphological defects in the films and difficulty in controlling the stoichiometry of the elements. The repetitive MAI treatments gradually fill the interstitial voids in the perovskite film and increase the average grain size up to 1.2 μm, which improves the charge-transfer property of the cells. The atomic Cl content, i.e., the x value, of the MAPbI3- xCl x film can also be simply controlled by changing the number of MAI treatments. The energy levels and resistive elements of the cells are strongly dependent on the x value of the MAPbI3- xCl x film. A maximum power conversion efficiency of 19.1% is achieved at x = 0.005.
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Affiliation(s)
- Jinwoong Jang
- Department of Chemistry , Kookmin University , Seoul 02707 , South Korea
| | - Geunpyo Choe
- Department of Chemistry , Kookmin University , Seoul 02707 , South Korea
| | - Sanggyu Yim
- Department of Chemistry , Kookmin University , Seoul 02707 , South Korea
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Shin D, Kang D, Lee JB, Ahn JH, Cho IW, Ryu MY, Cho SW, Jung NE, Lee H, Yi Y. Electronic Structure of Nonionic Surfactant-Modified PEDOT:PSS and Its Application in Perovskite Solar Cells with Reduced Interface Recombination. ACS APPLIED MATERIALS & INTERFACES 2019; 11:17028-17034. [PMID: 30990013 DOI: 10.1021/acsami.9b01545] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The interfacial properties of organolead halide perovskite solar cells (PSCs) affect the exciton and charge-transport dynamics significantly. Thus, proper modification of the interfaces between perovskite and charge-transport layers is an efficient method to increase the power conversion efficiency (PCE) of PSCs. In this work, we explore the effect of a nonionic surfactant, that is, Triton X-100 (TX) additive, in the poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) hole-transport layer. The electronic structure of TX-modified PEDOT:PSS is investigated with ultraviolet/X-ray photoelectron spectroscopy and X-ray absorption spectroscopy with various TX concentrations. The surface of the TX-modified PEDOT:PSS layer showed high TX content, and thus the semimetallic properties of PEDOT:PSS were suppressed conspicuously by its insulating nature. With the TX-modified PEDOT:PSS, the PCE of methylammonium lead iodide (MAPbI3) PSCs increased significantly. To elucidate the origin of the improved device performance, the electrical properties and photoluminescence were investigated comprehensively. Consequently, it was found that the TX additive inhibits interface recombination between PEDOT:PSS and MAPbI3, which is caused by the suppression of semimetallic properties of the PEDOT:PSS surface. Hence, we fabricated flexible PSCs successfully using a graphene electrode and TX-modified PEDOT:PSS.
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Affiliation(s)
| | | | | | | | - Il-Wook Cho
- Department of Physics , Kangwon National University , 1 Gangwondaehak-gil , Chuncheon-si , Gangwon-do 24341 , Republic of Korea
| | - Mee-Yi Ryu
- Department of Physics , Kangwon National University , 1 Gangwondaehak-gil , Chuncheon-si , Gangwon-do 24341 , Republic of Korea
| | - Sang Wan Cho
- Department of Physics , Yonsei University , 1 Yonseidae-gil , Wonju-si , Gangwon-do 26493 , Republic of Korea
| | | | - Hyunbok Lee
- Department of Physics , Kangwon National University , 1 Gangwondaehak-gil , Chuncheon-si , Gangwon-do 24341 , Republic of Korea
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Abstract
Design and modification of interfaces, always a critical issue for semiconductor devices, has become a primary tool to harness the full potential of halide perovskite (HaP)-based optoelectronics, including photovoltaics and light-emitting diodes. In particular, the outstanding improvements in HaP solar cell performance and stability can be primarily ascribed to a careful choice of the interfacial layout in the layer stack. In this review, we describe the unique challenges and opportunities of these approaches (section 1). For this purpose, we first elucidate the basic physical and chemical properties of the exposed HaP thin film and crystal surfaces, including topics such as surface termination, surface reactivity, and electronic structure (section 2). This is followed by discussing experimental results on the energetic alignment processes at the interfaces between the HaP and transport and buffer layers. This section includes understandings reached as well as commonly proposed and applied models, especially the often-questionable validity of vacuum level alignment, the importance of interface dipoles, and band bending as the result of interface formation (section 3). We follow this by elaborating on the impact of the interface formation on device performance, considering effects such as chemical reactions and surface passivation on interface energetics and stability. On the basis of these concepts, we propose a roadmap for the next steps in interfacial design for HaP semiconductors (section 4), emphasizing the importance of achieving control over the interface energetics and chemistry (i.e., reactivity) to allow predictive power for tailored interface optimization.
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Affiliation(s)
- Philip Schulz
- Institut Photovoltaïque d'Île-de-France (IPVF) , 91120 Palaiseau , France.,CNRS , Institut Photovoltaı̈que d'Île de France (IPVF) , UMR 9006 , 91120 Palaiseau , France.,National Center for Photovoltaics , National Renewable Energy Laboratory , Golden , Colorado 80401 , United States
| | - David Cahen
- Department of Materials and Interfaces , Weizmann Institute of Science , Rehovot 76100 , Israel
| | - Antoine Kahn
- Department of Electrical Engineering , Princeton University , Princeton , New Jersey 08544 , United States
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Zu F, Amsalem P, Egger DA, Wang R, Wolff CM, Fang H, Loi MA, Neher D, Kronik L, Duhm S, Koch N. Constructing the Electronic Structure of CH 3NH 3PbI 3 and CH 3NH 3PbBr 3 Perovskite Thin Films from Single-Crystal Band Structure Measurements. J Phys Chem Lett 2019; 10:601-609. [PMID: 30642163 DOI: 10.1021/acs.jpclett.8b03728] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Photovoltaic cells based on halide perovskites, possessing remarkably high power conversion efficiencies have been reported. To push the development of such devices further, a comprehensive and reliable understanding of their electronic properties is essential but presently not available. To provide a solid foundation for understanding the electronic properties of polycrystalline thin films, we employ single-crystal band structure data from angle-resolved photoemission measurements. For two prototypical perovskites (CH3NH3PbBr3 and CH3NH3PbI3), we reveal the band dispersion in two high-symmetry directions and identify the global valence band maxima. With these benchmark data, we construct "standard" photoemission spectra from polycrystalline thin film samples and resolve challenges discussed in the literature for determining the valence band onset with high reliability. Within the framework laid out here, the consistency of relating the energy level alignment in perovskite-based photovoltaic and optoelectronic devices with their functional parameters is substantially enhanced.
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Affiliation(s)
- Fengshuo Zu
- Institut für Physik & IRIS Adlershof , Humboldt-Universität zu Berlin , 12489 Berlin , Germany
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , 12489 Berlin , Germany
| | - Patrick Amsalem
- Institut für Physik & IRIS Adlershof , Humboldt-Universität zu Berlin , 12489 Berlin , Germany
| | - David A Egger
- Institute of Theoretical Physics , University of Regensburg , 93040 Regensburg , Germany
- Department of Materials and Interfaces , Weizmann Institute of Science , Rehovoth 76100 , Israel
| | - Rongbin Wang
- Institut für Physik & IRIS Adlershof , Humboldt-Universität zu Berlin , 12489 Berlin , Germany
- Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-based Functional Materials & Devices , Soochow University , Suzhou , Jiangsu 215123 , People's Republic of China
| | - Christian M Wolff
- Institut für Physik und Astronomie , Universität Potsdam , 14776 Potsdam , Germany
| | - Honghua Fang
- Photophysics & OptoElectronics, Zernike Institute for Advanced Materials , University of Groningen , Nijenborgh 4 , Groningen 9747 AG , The Netherlands
| | - Maria Antonietta Loi
- Photophysics & OptoElectronics, Zernike Institute for Advanced Materials , University of Groningen , Nijenborgh 4 , Groningen 9747 AG , The Netherlands
| | - Dieter Neher
- Institut für Physik und Astronomie , Universität Potsdam , 14776 Potsdam , Germany
| | - Leeor Kronik
- Department of Materials and Interfaces , Weizmann Institute of Science , Rehovoth 76100 , Israel
| | - Steffen Duhm
- Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-based Functional Materials & Devices , Soochow University , Suzhou , Jiangsu 215123 , People's Republic of China
| | - Norbert Koch
- Institut für Physik & IRIS Adlershof , Humboldt-Universität zu Berlin , 12489 Berlin , Germany
- Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , 12489 Berlin , Germany
- Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-based Functional Materials & Devices , Soochow University , Suzhou , Jiangsu 215123 , People's Republic of China
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12
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Cha MJ, Park YJ, Seo JH, Walker B. Depth-dependent electronic band structure at the Au/CH3NH3PbI3−xClx junction. Phys Chem Chem Phys 2019; 21:14541-14545. [DOI: 10.1039/c9cp00834a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The electronic properties of the interface between Au and the lead halide perovskite (CH3NH3PbI3−xClx) were investigated by ultraviolet photoelectron spectroscopy (UPS) and X-ray photoemission spectroscopy (XPS).
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Affiliation(s)
- Myung Joo Cha
- Department of Materials Physics
- Dong-A University
- Busan
- Republic of Korea
| | - Yu Jung Park
- Department of Materials Physics
- Dong-A University
- Busan
- Republic of Korea
| | - Jung Hwa Seo
- Department of Materials Physics
- Dong-A University
- Busan
- Republic of Korea
| | - Bright Walker
- Department of Chemistry
- Kyung Hee University
- Seoul
- Republic of Korea
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