AUTHOR=Peng Qi , Zheng Xin , Zhang Xiaoru , You Shuai , Li Lin , Zhao Yang , Zhang Shujing , Luo Long , Zeng Haipeng , Li Xiong 

TITLE=Radical Molecular Modulator for High-Performance Perovskite Solar Cells

JOURNAL=Frontiers in Chemistry

VOLUME=Volume 8 - 2020

YEAR=2020

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2020.00825

DOI=10.3389/fchem.2020.00825

ISSN=2296-2646

ABSTRACT=The long-term stability remains an issue impeding the commercialization of perovskite solar cells (PSCs). Generally, polycrystalline perovskite thin films have many defects on the grain boundaries, which affect the optoelectronic performance and stability of the devices under moisture, heat, illumination, and the presence of an electric field condition. The O-donor Lewis base is often employed to regulate the performance of PSCs such as carbonyl and carboxyl compounds. Herein, we have developed a concept of radical molecular modulation using O-donor group for high-performance perovskite photovoltaic devices. The judiciously designed radical modulators 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) which located at the perovskite grain boundary through interaction with the perovskite surface sites, effectively passivated the surface defects while templated the formation of large grain crystals of high electronic quality of the perovskite films. Accordingly, the optimized TEMPO modulated PSCs achieved a power conversion efficiency of 20.73% with superior stability. This work makes an important contribution for exploring effect of radical in perovskites to enhance the performance of PSCs and other optoelectronic devices.