Photophysics of Defect-Passivated Quasi-2D (PEA)2PbBr4 Perovskite Using an Organic Small Molecule

Abstract
2D Ruddlesden–Popper perovskites are promising candidates for energy-harvesting applications because of their tunable optical properties and ambient stability. Moreover, they are solution-processable and compatible with scalable manufacturing via various printing techniques. However, such methods often induce large degrees of heterogeneity because of poorly controlled crystallization. We address this issue by blending the well-known 2D perovskite (PEA)2PbBr4 with an organic small molecule, C8-BTBT. Terahertz (THz) absorption and temperature-dependent photoluminescence (PL) spectroscopy studies revealed changes in the photophysical properties of the perovskite without affecting its structural integrity upon adding C8-BTBT. The inclusion of trace amounts of C8-BTBT results in defect passivation both at perovskite platelet boundaries and at surfaces, as indicated by increased carrier lifetimes and substantially increased photoluminescence quantum yields (PLQY). This improves the responsivity of photodetectors using the 2D perovskite as an active layer. Our study highlights a straightforward strategy for fabricating high-quality 2D perovskites via large-area processing techniques.

Citation
Khan, J. I., Gedda, M., Wang, M., Yengel, E., Kreß, J. A., Vaynzof, Y., Anthopoulos, T. D., & Laquai, F. (2022). Photophysics of Defect-Passivated Quasi-2D (PEA)2PbBr4 Perovskite Using an Organic Small Molecule. ACS Energy Letters, 2450–2458. https://doi.org/10.1021/acsenergylett.2c00597

Acknowledgements
This publication is based upon work supported by the King Abdullah University of Science and Technology (KAUST) Office of Sponsored Research (OSR) under Award Nos. OSR-CARF/CCF-3079, OSR-CRG2018-3737, OSR-CRG2019-4093, OSR-CRG2020-4350, and OSR-CRG2018-3783. This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (ERC Grant Agreement No. 714067, ENERGYMAPS) and the Deutsche Forschungsgemeinschaft (DFG) in the framework of the Special Priority Program (SPP 2196) project PERFECT PVs (No. 424216076).

Publisher
American Chemical Society (ACS)

Journal
ACS Energy Letters

DOI
10.1021/acsenergylett.2c00597

Additional Links
https://pubs.acs.org/doi/10.1021/acsenergylett.2c00597

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