Abstract
Two-dimensional (2D) alternating cation (ACI) perovskite surface defects, especially dominant iodine vacancies (VI) and undercoordinated Pb2+, limit the performance of perovskite solar cells (PVSCs). To address the issue, 1-butyl-3-methylimidazolium trifluoro-methane-sulfonate (BMIMOTF) and its iodide counterpart (BMIMI) are utilized to modify the perovskite surface respectively. We find that BMIMI can change the perovskite surface, whereas BMIMOTF shows a nondestructive and more effective defect passivation, giving significantly reduced defect density and suppressed charge-carrier nonradiative recombination. This mainly attributes to the marked passivation efficacy of OTF− anion on VI and undercoordinated Pb2+, rather than BMIMI+ cation. Benefiting from the rational surface-modification of BMMIMOTF, the films exhibit an optimized energy level alignment, enhanced hydrophobicity and suppressed ion migration. Consequently, the BMIMOTF-modified devices achieve an impressive efficiency of 21.38% with a record open-circuit voltage of 1.195 V, which is among the best efficiencies reported for 2D PVSCs, and display greatly enhanced humidity and thermal stability.
Original language | English |
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Pages (from-to) | 354-362 |
Number of pages | 9 |
Journal | Journal of Energy Chemistry |
Volume | 84 |
DOIs | |
State | Published - Sep 2023 |
Bibliographical note
Publisher Copyright:© 2023 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences
Keywords
- 2D ACI perovskite solar cells
- Charge-carrier nonradiative recombination
- Energy level alignment
- Ionic migration
- Stability
- Surface defects passivation
ASJC Scopus subject areas
- Fuel Technology
- Energy Engineering and Power Technology
- Energy (miscellaneous)
- Electrochemistry