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Doped Bilayer Tin(IV) Oxide Electron Transport Layer for High Open‐Circuit Voltage Planar Perovskite Solar Cells with Reduced Hysteresis
Author(s) -
Ye Jiajiu,
Li Yuze,
Medjahed Asma Aicha,
Pouget Stéphanie,
Aldakov Dmitry,
Liu Yueli,
Reiss Peter
Publication year - 2021
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.202005671
Subject(s) - bilayer , materials science , perovskite (structure) , optoelectronics , tin oxide , doping , energy conversion efficiency , hysteresis , open circuit voltage , x ray photoelectron spectroscopy , layer (electronics) , analytical chemistry (journal) , nanotechnology , chemical engineering , chemistry , voltage , crystallography , biochemistry , physics , membrane , engineering , quantum mechanics , chromatography
Tin oxide (SnO 2 ) is an emerging electron transport layer (ETL) material in halide perovskite solar cells (PSCs). Among current limitations, open‐circuit voltage ( V OC ) loss is one of the major factors to be addressed for further improvement. Here a bilayer ETL consisting of two SnO 2 nanoparticle layers doped with different amounts of ammonium chloride is proposed. As demonstrated by photoelectron spectroscopy and photophysical studies, the main effect of the novel ETL is to modify the energy level alignment at the SnO 2 /perovskite interface, which leads to decreased carrier recombination, enhanced electron transfer, and reduced voltage loss. Moreover, X‐ray diffraction reveals reduced strain in perovskite layers grown on bilayer ETLs with respect to single‐layer ETLs, further contributing to a decrease of carrier recombination processes. Finally, the bilayer approach enables the more reproducible preparation of smooth and pinhole‐free ETLs as compared to single‐step deposition ETLs. PSCs with the doped bilayer SnO 2 ETL demonstrate strongly increased V OC values of up to 1.21 V with a power conversion efficiency of 21.75% while showing negligible hysteresis and enhanced stability. Moreover, the SnO 2 bilayer can be processed at low temperature (70 °C), and has therefore a high potential for use in tandem devices or flexible PSCs.