Ligand Homogenized Br–I Wide-Bandgap Perovskites for Efficient NiO<sub><i>x</i></sub>-Based Inverted Semitransparent and Tandem Solar Cells
Xing Zhang, Qiaoyan Ma, Yousheng Wang, Jianzha Zheng, Quanxi Liu, Liming Liu, Peng Yang, Wujie He, Ye Cao, Weiyuan Duan, Kaining Ding, Yaohua Mai
Abstract
Phase heterogeneity of bromine–iodine (Br–I) mixed wide-bandgap (WBG) perovskites has detrimental effects on solar cell performance and stability. Here, we report a heterointerface anchoring strategy to homogenize the Br–I distribution and mitigate the segregation of Br-rich WBG-perovskite phases. We find that methoxy-substituted phenyl ethylammonium ( x -MeOPEA + ) ligands not only contribute to the crystal growth with vertical orientation but also promote halide homogenization and defect passivation near the buried perovskite/hole transport layer (HTL) interface as well as reduce trap-mediated recombination. Based on improvements in WBG-perovskite homogeneity and heterointerface contacts, NiO x -based opaque WBG-perovskite solar cells (WBG-PSCs) achieved impressive open-circuit voltage ( V oc ) and fill factor (FF) values of 1.22 V and 83%, respectively. Moreover, semitransparent WBG-PSCs exhibit a PCE of 18.5% (15.4% for the IZO front side) and a high FF of 80.7% (79.4% for the IZO front side) for a designated illumination area (da) of 0.12 cm 2 . Such a strategy further enables 24.3%-efficient two-terminal perovskite/silicon (double-polished) tandem solar cells (da of 1.159 cm 2 ) with a high V oc of over 1.90 V. The tandem devices also show high operational stability over 1000 h during T 90 lifetime measurements.