Multi band gap electronic structure in CH3NH3PbI3
Organo-lead halide perovskite solar cells represent a revolutionary shift in solar photovoltaics, introducing relatively soft defect containing semiconductors as materials with excellent charge collection for both electrons and holes. Although they are based on the nominally simple cubic perovskite...
| Main Authors: | , , , , , , |
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| Format: | Journal Article |
| Language: | English |
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2019
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| Online Access: | https://hdl.handle.net/10356/85903 http://hdl.handle.net/10220/48281 |
| _version_ | 1811676453962514432 |
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| author | Ong, Khuong P. Wu, Shunnian Nguyen, Tien Hoa Singh, David J. Fan, Zhen Sullivan, Michael B. Dang, Cuong |
| author2 | School of Electrical and Electronic Engineering |
| author_facet | School of Electrical and Electronic Engineering Ong, Khuong P. Wu, Shunnian Nguyen, Tien Hoa Singh, David J. Fan, Zhen Sullivan, Michael B. Dang, Cuong |
| author_sort | Ong, Khuong P. |
| collection | NTU |
| description | Organo-lead halide perovskite solar cells represent a revolutionary shift in solar photovoltaics, introducing relatively soft defect containing semiconductors as materials with excellent charge collection for both electrons and holes. Although they are based on the nominally simple cubic perovskite structure, these compounds are in fact very complex. For example, in (CH3NH3)PbI3 the dynamics and ensuing structural fluctuations associated with the (CH3NH3)+ ions and the interplay with the electronic properties are still not fully understood, despite extensive study. Here, using ab-initio calculations, we show that at room and higher temperature, the rotation of CH3NH3 molecules can be viewed as effectively giving local structures that are cubic and tetragonal like from the point of view of the PbI3 framework, though in fact having lower symmetry. Both of these structures are locally polar, with sizable polarization, ~10 μC/cm2 due to the dipoles on the organic. They become energetically degenerate in the volume range, V ~ 250 Å3/f.u–265 Å3/f.u. We also find very significant dependence of the band gap on the local structure. This type of transition is analogous to a transition between two ferroelectric structures, where in-spite of strong electron phonon coupling, there is strong screening of charged defects which can lead to enhanced mobility and charge collection. The results provide insights into the enhanced light absorption near the band edge and good charge collection in this material. |
| first_indexed | 2024-10-01T02:21:43Z |
| format | Journal Article |
| id | ntu-10356/85903 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2024-10-01T02:21:43Z |
| publishDate | 2019 |
| record_format | dspace |
| spelling | ntu-10356/859032020-03-07T13:57:29Z Multi band gap electronic structure in CH3NH3PbI3 Ong, Khuong P. Wu, Shunnian Nguyen, Tien Hoa Singh, David J. Fan, Zhen Sullivan, Michael B. Dang, Cuong School of Electrical and Electronic Engineering Centre for OptoElectronics and Biophotonics (COEB) DRNTU::Engineering::Electrical and electronic engineering Electronic Properties and Materials Solar Cells Organo-lead halide perovskite solar cells represent a revolutionary shift in solar photovoltaics, introducing relatively soft defect containing semiconductors as materials with excellent charge collection for both electrons and holes. Although they are based on the nominally simple cubic perovskite structure, these compounds are in fact very complex. For example, in (CH3NH3)PbI3 the dynamics and ensuing structural fluctuations associated with the (CH3NH3)+ ions and the interplay with the electronic properties are still not fully understood, despite extensive study. Here, using ab-initio calculations, we show that at room and higher temperature, the rotation of CH3NH3 molecules can be viewed as effectively giving local structures that are cubic and tetragonal like from the point of view of the PbI3 framework, though in fact having lower symmetry. Both of these structures are locally polar, with sizable polarization, ~10 μC/cm2 due to the dipoles on the organic. They become energetically degenerate in the volume range, V ~ 250 Å3/f.u–265 Å3/f.u. We also find very significant dependence of the band gap on the local structure. This type of transition is analogous to a transition between two ferroelectric structures, where in-spite of strong electron phonon coupling, there is strong screening of charged defects which can lead to enhanced mobility and charge collection. The results provide insights into the enhanced light absorption near the band edge and good charge collection in this material. ASTAR (Agency for Sci., Tech. and Research, S’pore) MOE (Min. of Education, S’pore) Published version 2019-05-21T01:58:11Z 2019-12-06T16:12:22Z 2019-05-21T01:58:11Z 2019-12-06T16:12:22Z 2019 Journal Article Ong, K. P., Wu, S., Nguyen, T. H., Singh, D. J., Fan, Z., Sullivan, M. B., & Dang, C. (2019). Multi Band Gap Electronic Structure in CH3NH3PbI3. Scientific Reports, 9, 2144-. doi:10.1038/s41598-018-38023-2 https://hdl.handle.net/10356/85903 http://hdl.handle.net/10220/48281 10.1038/s41598-018-38023-2 en Scientific Reports © 2019 The Author(s) (Nature Publishing Group). This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. 8 p. application/pdf |
| spellingShingle | DRNTU::Engineering::Electrical and electronic engineering Electronic Properties and Materials Solar Cells Ong, Khuong P. Wu, Shunnian Nguyen, Tien Hoa Singh, David J. Fan, Zhen Sullivan, Michael B. Dang, Cuong Multi band gap electronic structure in CH3NH3PbI3 |
| title | Multi band gap electronic structure in CH3NH3PbI3 |
| title_full | Multi band gap electronic structure in CH3NH3PbI3 |
| title_fullStr | Multi band gap electronic structure in CH3NH3PbI3 |
| title_full_unstemmed | Multi band gap electronic structure in CH3NH3PbI3 |
| title_short | Multi band gap electronic structure in CH3NH3PbI3 |
| title_sort | multi band gap electronic structure in ch3nh3pbi3 |
| topic | DRNTU::Engineering::Electrical and electronic engineering Electronic Properties and Materials Solar Cells |
| url | https://hdl.handle.net/10356/85903 http://hdl.handle.net/10220/48281 |
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