Role of water in suppressing pecombination pathways in CH3NH3PbI3 perovskite solar cells
Moisture degradation of halide perovskites is the Achilles heel of perovskite solar cells. A surprising revelation in 2014 about the beneficial effects of controlled humidity in enhancing device efficiencies overthrew established paradigms on perovskite solar cell fabrication. Despite the extensive...
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| Format: | Journal Article |
| Language: | English |
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2020
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| Online Access: | https://hdl.handle.net/10356/138050 |
| _version_ | 1811680414810505216 |
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| author | Solanki, Ankur Lim, Swee Sien Mhaisalkar, Subodh Sum, Tze Chien |
| author2 | School of Materials Science & Engineering |
| author_facet | School of Materials Science & Engineering Solanki, Ankur Lim, Swee Sien Mhaisalkar, Subodh Sum, Tze Chien |
| author_sort | Solanki, Ankur |
| collection | NTU |
| description | Moisture degradation of halide perovskites is the Achilles heel of perovskite solar cells. A surprising revelation in 2014 about the beneficial effects of controlled humidity in enhancing device efficiencies overthrew established paradigms on perovskite solar cell fabrication. Despite the extensive studies on water additives in perovskite solar cell processing that followed, detailed understanding of the role of water from the photophysical perspective remains lacking; specifically, the interplay between the induced morphological effects and the intrinsic recombination pathways. Through ultrafast optical spectroscopy, we show that both the monomolecular and bimolecular recombination rate constants decrease by approximately 1 order with the addition of an optimal 1% H2O by volume in CH3NH3PbI3 as compared to the reference (without the H2O additive). Correspondingly, the trap density reduces from 4.8 × 1017 cm-3 (reference) to 3.2 × 1017 cm-3 with 1% H2O. We obtained an efficiency of 12.3% for the champion inverted CH3NH3PbI3 perovskite solar cell (1% H2O additive) as compared to the 10% efficiency for the reference cell. Increasing the H2O content further is deleterious for the device. Trace amounts of H2O afford the benefits of surface trap passivation and suppression of trap-mediated recombination, whereas higher concentrations result in a preferential dissolution of methylammonium iodide during fabrication that increases the trap density (MA vacancies). Importantly, our study reveals the effects of trace H2O additives on the photophysical properties of CH3NH3PbI3 films. |
| first_indexed | 2024-10-01T03:24:41Z |
| format | Journal Article |
| id | ntu-10356/138050 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2024-10-01T03:24:41Z |
| publishDate | 2020 |
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| spelling | ntu-10356/1380502023-02-28T19:51:20Z Role of water in suppressing pecombination pathways in CH3NH3PbI3 perovskite solar cells Solanki, Ankur Lim, Swee Sien Mhaisalkar, Subodh Sum, Tze Chien School of Materials Science & Engineering School of Physical and Mathematical Sciences Interdisciplinary Graduate School (IGS) Energy Research Institute @ NTU (ERI@N) Research Techno Plaza Science::Physics CH3NH3PbI3 Photovoltaics Moisture degradation of halide perovskites is the Achilles heel of perovskite solar cells. A surprising revelation in 2014 about the beneficial effects of controlled humidity in enhancing device efficiencies overthrew established paradigms on perovskite solar cell fabrication. Despite the extensive studies on water additives in perovskite solar cell processing that followed, detailed understanding of the role of water from the photophysical perspective remains lacking; specifically, the interplay between the induced morphological effects and the intrinsic recombination pathways. Through ultrafast optical spectroscopy, we show that both the monomolecular and bimolecular recombination rate constants decrease by approximately 1 order with the addition of an optimal 1% H2O by volume in CH3NH3PbI3 as compared to the reference (without the H2O additive). Correspondingly, the trap density reduces from 4.8 × 1017 cm-3 (reference) to 3.2 × 1017 cm-3 with 1% H2O. We obtained an efficiency of 12.3% for the champion inverted CH3NH3PbI3 perovskite solar cell (1% H2O additive) as compared to the 10% efficiency for the reference cell. Increasing the H2O content further is deleterious for the device. Trace amounts of H2O afford the benefits of surface trap passivation and suppression of trap-mediated recombination, whereas higher concentrations result in a preferential dissolution of methylammonium iodide during fabrication that increases the trap density (MA vacancies). Importantly, our study reveals the effects of trace H2O additives on the photophysical properties of CH3NH3PbI3 films. NRF (Natl Research Foundation, S’pore) MOE (Min. of Education, S’pore) Accepted version 2020-04-22T13:03:17Z 2020-04-22T13:03:17Z 2019 Journal Article Solanki, A., Lim, S. S., Mhaisalkar, S., & Sum, T. C. (2019). Role of water in suppressing pecombination pathways in CH3NH3PbI3 perovskite solar cells. ACS Applied Materials and Interfaces, 11(28), 25474-25482. doi:10.1021/acsami.9b00793 1944-8244 https://hdl.handle.net/10356/138050 10.1021/acsami.9b00793 31179683 2-s2.0-85070024890 28 11 25474 25482 en NTU Start-up Grant M4080514 MOE2016-T2-1-034 US Office of Naval Research (ONRGNICOP-N62909-17-1-2155 NRF2018-ITC001-001 NRF-NRFI-2018-04 ACS Applied Materials and Interfaces https://doi.org/10.21979/N9/WUEMZC This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Applied Materials and Interfaces, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acsami.9b00793 application/pdf application/pdf |
| spellingShingle | Science::Physics CH3NH3PbI3 Photovoltaics Solanki, Ankur Lim, Swee Sien Mhaisalkar, Subodh Sum, Tze Chien Role of water in suppressing pecombination pathways in CH3NH3PbI3 perovskite solar cells |
| title | Role of water in suppressing pecombination pathways in CH3NH3PbI3 perovskite solar cells |
| title_full | Role of water in suppressing pecombination pathways in CH3NH3PbI3 perovskite solar cells |
| title_fullStr | Role of water in suppressing pecombination pathways in CH3NH3PbI3 perovskite solar cells |
| title_full_unstemmed | Role of water in suppressing pecombination pathways in CH3NH3PbI3 perovskite solar cells |
| title_short | Role of water in suppressing pecombination pathways in CH3NH3PbI3 perovskite solar cells |
| title_sort | role of water in suppressing pecombination pathways in ch3nh3pbi3 perovskite solar cells |
| topic | Science::Physics CH3NH3PbI3 Photovoltaics |
| url | https://hdl.handle.net/10356/138050 |
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