A Selective Targeting Anchor Strategy Affords Efficient and Stable Ideal‐Bandgap Perovskite Solar Cells
Zheng Liang, Huifen Xu, Yong Zhang, Guozhen Liu, Shenglong Chu, Yuli Tao, Xiaoxiao Xu, Shendong Xu, Liying Zhang, Xiaojing Chen, Baomin Xu, Zhengguo Xiao, Xu Pan, Jiajiu Ye
Abstract
Abstract Mixed lead–tin perovskite solar cells (LTPSCs) with an ideal bandgap are demonstrated as a promising candidate to reach higher power conversion efficiency (PCE) than their Pb‐counterparts. Herein, a Br‐free mixed lead–tin perovskite material, FA 0.8 MA 0.2 Pb 0.8 Sn 0.2 I 3 , with a bandgap of 1.33 eV, as a perovskite absorber, is selected. Through density functional theory calculations and optoelectronic techniques, it is demonstrated that both Pb‐ and Sn‐related A‐site vacancies are pushed into deeper energetic depth, causing severe nonradiative recombination. Hence, a selective targeting anchor strategy that employs phenethylammonium iodide and ethylenediamine diiodide as co‐modifiers to selectively anchor with Pb‐ and Sn‐related active sites and passivate bimetallic traps, respectively, is established. Furthermore, the selectivity of the molecular oriented anchor passivation is demonstrated through energetic depth specificity of Pb‐ and Sn‐related traps. As a result, a substantially enhanced open‐circuit voltage ( V OC ) from 0.79 to 0.90 V for the LTPSCs is achieved, yielding a champion PCE of 22.51%, which is the highest PCE among the reported ideal‐bandgap PSCs. The V OC loss is reduced to 0.43 V.