Passivation of Grain Boundary by Squaraine Zwitterions for Defect Passivation and Efficient Perovskite Solar Cells
| Autor: | Shuzi Hayase, Anusha Pradhan, Chi Huey Ng, Zhen Wang, Atul S.M. Tripathi, Shyam S. Pandey, Manish Pandey, Tingli Ma, Putao Zhang, Muhammad Akmal Kamarudin |
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| Rok vydání: | 2019 |
| Předmět: |
Materials science
Passivation Exciton Halide Charge density 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences Chemical engineering Molecule General Materials Science Density functional theory Grain boundary 0210 nano-technology Perovskite (structure) |
| Zdroj: | ACS Applied Materials & Interfaces. 11:10012-10020 |
| ISSN: | 1944-8252 1944-8244 |
| DOI: | 10.1021/acsami.8b22044 |
| Popis: | Unavoidable defects in grain boundaries (GBs) are detrimental and critically influence the organometal halide perovskite performance and stability. To address this issue, semiconducting molecules have been employed to passivate traps along perovskite GBs. Here, we designed and synthesized three squaraine molecules (SQ) with zwitterionic structure to interact with under-coordinated Pb2+ and passivate Pb-I antisite defects. Density functional theory calculation shows symmetric O atoms could coordinate with perovskite grains simultaneously, resulting in continuous charge distribution at the SQ-perovskite interface. The energetic traps distribution in CH3NH3PbI3 perovskite is influenced significantly by the interaction between SQ and perovskite as analyzed by thermally stimulated current, in which the deep-level defects are considerably reduced due to efficient SQ passivation. In addition, we explore how SQ molecules with different energy offset affect the charge extraction, which is suggested to facilitate exciton separation at the perovskite-SQ interface. These benefits lead to enhanced perovskite efficiency from 15.77 to 18.83% with the fill factor approaching 80%, which is among the highest efficiency reported for MAPbI3 solar cells fabricated in an ambient environment at 60% relative humidity (RH). Considerable retardation of perovskite device degradation was achieved, retaining 90% of initial efficiency when kept 600 h at 60 ± 5% RH. |
| Databáze: | OpenAIRE |
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