Field‐Effect Control in Hole Transport Layer Composed of Li:NiO/NiO for Highly Efficient Inverted Planar Perovskite Solar Cells
Liang Zhao, Xuewen Sun, Qiannan Yao, Sheng Huang, Lei Zhu, Jian Song, Yulong Zhao, Yinghuai Qiang
Abstract
Abstract Perovskite solar cells (PSCs) have been recognized as fascinating optoelectronic devices with a rapid progress of the power conversion efficiency (PCE). However, serious carrier recombination at charge transport layer (CTL)/perovskite interface limits further development of PSCs. Therefore, carrier dynamics at interface should be finely regulated to achieve a satisfied performance. Herein, a hole transport layer (HTL) is developed with a bilayer film composed of Li:NiO/NiO, in which NiO directly contacts with perovskite film. The prepared HTL is a p‐p + homojunction as Li:NiO film has higher concentration of carrier than NiO. Energy level alignment in Li:NiO/NiO HTL reflects a hole transport improvement by both built‐in electric field and interface effective field. The additional drive forces generated by the above field effects in HTL present a significant enhancement for carrier extraction and transport at HTL/perovskite interface. As a result, the inverted planar PSC with the Li:NiO/NiO HTL delivers an improved PCE up to 19.04% from 15.40% of the control one, which also shows a high fill factor of 82.83%, indicating a low level of carrier nonradiative recombination. This work provides new insights on the carrier dynamics control in CTL/perovskite interface, which is meaningful for designing excellent PSCs.