Zhou Xiangqing, Li Xingliang, Shi Biao, Wang Pengyang, Du Xiaona, Zhao Ying, Zhang Xiaodan
Institute of Photoelectronic Thin Film Devices and Technology, Renewable Energy Conversion and Storage Center, State Key Laboratory of Photovoltaic Materials and Cells, Nankai University, Tianjin 300350, P. R. China.
Tianjin Key Laboratory of Efficient Utilization of Solar Energy, Tianjin 300350, P. R. China.
ACS Nano. 2025 Mar 25;19(11):11187-11196. doi: 10.1021/acsnano.4c18395. Epub 2025 Mar 11.
Mixed halide wide-bandgap (WBG) perovskites, widely used as a top-cell absorber in tandem solar cells, exhibit severe photoinduced halide phase segregation. A feasible solution is to exploit pure-iodide WBG perovskites, essentially increasing Cs content instead of Br to achieve bandgap widening. However, the efficiency of pure-iodine WBG perovskite solar cells (PSCs) reported so far has been inferior to that of the typical mixed halide WBG PSCs due to complex nucleation and phase transition processes, leading to poor crystallization quality and a high density of defect states in pure-iodine WBG perovskites. Here, by combining lead thiocyanate (Pb(SCN)) and oleylamine hydrochloride (OAmCl) with the CsDMAMAPbI perovskite precursor, a homogeneous phase distribution is obtained, resulting in enhanced crystallization and a reduction of excess lead source defects. With this approach, the resulting film quality is improved along with fewer surface-bulk defects as well as beneficial surface electronic properties. As a result, the pure-iodide WBG PSCs deliver a high efficiency of 21.55%, an extremely high fill factor of 86.03%, and superior photostability. The target film is fundamentally free of phase segregation under continuous light for 12 h (AM 1.5 G illumination, xenon lamp, 1 sun).
混合卤化物宽带隙（WBG）钙钛矿作为叠层太阳能电池的顶电池吸收层被广泛应用，但其存在严重的光致卤化物相分离现象。一个可行的解决方案是采用纯碘化物WBG钙钛矿，通过本质上增加铯（Cs）含量而非溴（Br）含量来实现带隙拓宽。然而，由于复杂的成核和相变过程，迄今报道的纯碘化物WBG钙钛矿太阳能电池（PSC）的效率一直低于典型的混合卤化物WBG PSC，这导致纯碘化物WBG钙钛矿的结晶质量较差且缺陷态密度较高。在此，通过将硫氰酸铅（Pb(SCN)）和油胺盐酸盐（OAmCl）与CsDMAMAPbI钙钛矿前驱体相结合，获得了均匀的相分布，从而增强了结晶并减少了过量铅源缺陷。采用这种方法，所得薄膜质量得到改善，表面 - 体缺陷减少，同时具有有益的表面电子特性。结果，纯碘化物WBG PSC实现了21.55%的高效率、86.03%的极高填充因子以及优异的光稳定性。在连续光照12小时（AM 1.5 G光照，氙灯，1个太阳）下，目标薄膜基本上没有相分离现象。
