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Self‐Aggregation‐Controlled Rapid Chemical Bath Deposition of SnO 2 Layers and Stable Dark Depolarization Process for Highly Efficient Planar Perovskite Solar Cells
Author(s) -
Ko Yohan,
Kim Youbin,
Lee Chanyong,
Kim Taemin,
Kim Seungkyu,
Yun Yong Ju,
Gwon Huijeong,
Lee NamHo,
Jun Yongseok
Publication year - 2020
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.202000501
Subject(s) - tin oxide , materials science , energy conversion efficiency , perovskite solar cell , ionic bonding , charge carrier , dielectric spectroscopy , chemical bath deposition , chemical engineering , analytical chemistry (journal) , solar cell , nanotechnology , chemical physics , electrode , doping , electrochemistry , chemistry , thin film , optoelectronics , ion , organic chemistry , engineering , chromatography
Abstract Planar perovskite solar cells (PSCs) incorporating n‐type SnO 2 have attracted significant interest because of their excellent photovoltaic performance. However, the film fabrication of SnO 2 is limited by self‐aggregation and inhomogeneous growth of the intermediate phase, which produces poor morphology and properties. In this study, a self‐controlled SnO 2 layer is fabricated directly on a fluorine‐doped tin oxide (FTO) surface through simple and rapid chemical bath deposition. The PSCs based on this hydrolyzed SnO 2 layer exhibit an excellent power conversion efficiency of 20.21 % with negligible hysteresis. Analysis of the electrochemical impedance spectroscopy on the charge transport dynamics indicates that the bias voltage influences both interfacial charge transportation and the ionic double layer under illumination. The hydrolyzed SnO 2 ‐based PSCs demonstrate a faster ionic charge response time of 2.5 ms in comparison with 100.5 ms for the hydrolyzed TiO 2 ‐based hysteretic PSCs. The results of quasi‐steady‐state carrier transportation indicate that a dynamic hysteresis in the J – V curves can be explained by complex ionic‐electronic kinetics owing to the slow ionic charge redistribution and hole accumulation caused by electrode polarization, which causes an increase in charge recombination. This study reveals that SnO 2 ‐based PSCs lead to a stabilized dark depolarization process compared with TiO 2 ‐based PSCs, which is relevant to the charge transport dynamics in the high‐performing planar SnO 2 ‐based PSCs.