Two-dimensional Ruddlesden–Popper layered perovskite solar cells based on phase-pure thin films

• Published in: Nature energy Vol. 6; no. 1; pp. 38 - 45
• Main Authors: Liang, Chao, Gu, Hao, Xia, Yingdong, Wang, Zhuo, Liu, Xiaotao, Xia, Junmin, Zuo, Shouwei, Hu, Yue, Gao, Xingyu, Hui, Wei, Chao, Lingfeng, Niu, Tingting, Fang, Min, Lu, Hui, Dong, Han, Yu, Hui, Chen, Shi, Ran, Xueqin, Song, Lin, Li, Bixin, Zhang, Jing, Peng, Yong, Shao, Guosheng, Wang, Jianpu, Chen, Yonghua, Xing, Guichuan, Huang, Wei
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.01.2021; Nature Publishing Group
• Subjects: 639/301/299/946; 639/4077/4072/4062; 639/4077/909/4101; Acetic acid; Dimensional stability; Economics and Management; Energy; Energy conversion efficiency; Energy Policy; Energy Storage; Energy Systems; Iodides; Metal halides; Molten salts; Optoelectronics; Perovskites; Photovoltaic cells; Quantum wells; Renewable and Green Energy; Solar cells; Thin films; Wells
• ISSN: 2058-7546; 2058-7546
• DOI: 10.1038/s41560-020-00721-5

Two-dimensional Ruddlesden–Popper layered metal-halide perovskites have attracted increasing attention for their desirable optoelectronic properties and improved stability compared to their three-dimensional counterparts. However, such perovskites typically consist of multiple quantum wells with a random well width distribution. Here, we report phase-pure quantum wells with a single well width by introducing molten salt spacer n -butylamine acetate, instead of the traditional halide spacer n -butylamine iodide. Due to the strong ionic coordination between n -butylamine acetate and the perovskite framework, a gel of a uniformly distributed intermediate phase can be formed. This allows phase-pure quantum well films with microscale vertically aligned grains to crystallize from their respective intermediate phases. The resultant solar cells achieve a power conversion efficiency of 16.25% and a high open voltage of 1.31 V. After keeping them in 65 ± 10% humidity for 4,680 h, under operation at 85 °C for 558 h, or continuous light illumination for 1,100 h, the cells show <10% efficiency degradation. Two-dimensional Ruddlesden–Popper layered metal-halide perovskites show better performance over three-dimensional versions, but are typically based on quantum wells with random width distribution. Liang et al. show that introducing molten salt spacers gives phase-pure quantum wells and improved solar cell performance.