Researchers from Shanghai Institute of Optics and Fine Mechanics (SIOM), Chinese Academy of Sciences (CAS) collaborated with Chongqing University proved that besides the optimal bandgap in α-FAPbI₃, the higher polaron mobility induced by the lattice distortion due to A-X co-substitution modulation could also result in the outstanding solar energy conversion performance. This study has been published in Journal of Energy Chemistry on Sep. 3, 2022.

With the shortage of fossil energy have been a public human being's problem, recent years have witnessed a surge of researches pertaining to the improvement of the photoelectric conversion efficiency of solar cells. At the same time, the cutting-edge researches on low-cost and high-efficiency solar cells in China will also provide an important theoretical and experimental basis for the overall goal of China's carbon neutrality for 2060.

Researchers investigated the ultrafast photogenerated carrier dynamics of the black cubic phase α-FAPbI₃ thin films using time-resolved terahertz spectroscopy. The bandgap is tuned by component substitution through bandgap engineering, and it is found that the polaron mobility of the sample with a smaller bandgap is larger. Then, by analyzing the dispersion relationship of the THz photoconductivity of photogenerated carriers, they found that the larger polaron mobility of the sample with smaller band gap is mainly due to the longer scattering time of the carrier.

Researchers proved that besides the optimal bandgap in α-FAPbI₃, the higher polaron mobility induced by the lattice distortion due to A-X co-substitution modulation could also result in outstanding solar energy conversion performance. On the other hand, this work provides an important research basis for device design to further improve the efficiency of perovskite solar cells.

Figure: (a) The Tauc plots of (FAPbI₃)_0.85(MAPbBr₃)_0.15 (FA0.85) and (FAPbI₃)_0.95(MAPbI₃)_0.05 (FA0.95). (b) The polaron mobility of FA0.85 and FA0.95. (c) The scattering time of FA0.85 and FA0.95. (Image by SIOM)

 Article website:
https://doi.org/10.1016/j.jechem.2022.08.039

Contact:
WU Xiufeng
General Administrative Office
Shanghai Institute of Optics and Fine Mechanics, CAS
Email: xfwu@siom.ac.cn
Web: http://english.siom.cas.cn/