Dielectric screening in perovskite photovoltaics

• Published in: Nature communications Vol. 12; no. 1; pp. 2479 - 11
• Main Authors: Su, Rui, Xu, Zhaojian, Wu, Jiang, Luo, Deying, Hu, Qin, Yang, Wenqiang, Yang, Xiaoyu, Zhang, Ruopeng, Yu, Hongyu, Russell, Thomas P., Gong, Qihuang, Zhang, Wei, Zhu, Rui
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 30.04.2021; Nature Publishing Group; Nature Portfolio
• Subjects: 140/125; 147/135; 147/136; 147/143; 147/3; 639/301/299/946; 639/624/1075/524; Absorption cross sections; Collaboration; Defects; Dielectric properties; Dielectrics; Energy conversion efficiency; Engineering; Humanities and Social Sciences; Laboratories; Low voltage; multidisciplinary; Open circuit voltage; Perovskites; Photovoltaic cells; photovoltaic technology; Photovoltaics; Recombination; Science; Science (multidisciplinary); Screening; Semiconductors; solar cells; SOLAR ENERGY; Voltage
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-021-22783-z

The performance of perovskite photovoltaics is fundamentally impeded by the presence of undesirable defects that contribute to non-radiative losses within the devices. Although mitigating these losses has been extensively reported by numerous passivation strategies, a detailed understanding of loss origins within the devices remains elusive. Here, we demonstrate that the defect capturing probability estimated by the capture cross-section is decreased by varying the dielectric response, producing the dielectric screening effect in the perovskite. The resulting perovskites also show reduced surface recombination and a weaker electron-phonon coupling. All of these boost the power conversion efficiency to 22.3% for an inverted perovskite photovoltaic device with a high open-circuit voltage of 1.25 V and a low voltage deficit of 0.37 V (a bandgap ~1.62 eV). Our results provide not only an in-depth understanding of the carrier capture processes in perovskites, but also a promising pathway for realizing highly efficient devices via dielectric regulation. Performance of perovskite photovoltaics is greatly affected by undesirable defects that contribute to non-radiative losses. Here, the authors mitigate these losses by doping perovskite with KI to alter the dielectric response, thus defect capturing probability, resulting in inverted device with PCE of 22.3% and low voltage loss.