Abstract：
The perovskite-inspired Cu2 AgBiI6 (CABI) material has been gaining increasing momentum as photovoltaic (PV) absorber due to its low toxicity, intrinsic air stability, direct bandgap, and a high absorption coefficient in the range of 105 cm-1 . However, the power conversion efficiency (PCE) of existing CABI-based PVs is still seriously constrained by the presence of both intrinsic and surface defects. Herein, antimony (III) (Sb3+ ) is introduced into the octahedral lattice sites of the CABI structure, leading to CABI-Sb with larger crystalline domains than CABI. The alloying of Sb3+ with bismuth (III) (Bi3+ ) induces changes in the local structural symmetry that dramatically increase the formation energy of intrinsic defects. Light-intensity dependence and electron impedance spectroscopic studies show reduced trap-assisted recombination in the CABI-Sb PV devices. CABI-Sb solar cells feature a nearly 40% PCE enhancement (from 1.31% to 1.82%) with respect to the CABI devices mainly due to improvement in short-circuit current density. This work will promote future compositional design studies to enhance the intrinsic defect tolerance of next-generation wide-bandgap absorbers for high-performance and stable PVs.
摘要：
钙钛矿启发的Cu2AgBiI6（CABI）材料由于其低毒性而作为光伏（PV）吸收剂获得了越来越大的动力，固有空气稳定性，直接带隙,和在105cm-1范围内的高吸收系数。然而,现有的基于CABI的PV的功率转换效率(PCE)仍然受到固有缺陷和表面缺陷两者的存在的严重限制。在这里，将锑（III）（Sb3）引入CABI结构的八面体晶格位点，导致CABI-Sb具有比CABI更大的晶畴。Sb3与铋（III）（Bi3）的合金化会引起局部结构对称性的变化，从而显着增加固有缺陷的形成能。光强依赖性和电子阻抗谱研究表明，CABI-SbPV器件中陷阱辅助的复合减少。CABI-Sb太阳能电池相对于CABI器件具有近40%的PCE增强(从1.31%到1.82%),这主要是由于短路电流密度的改善。这项工作将促进未来的成分设计研究，以增强用于高性能和稳定PV的下一代宽带隙吸收体的固有缺陷耐受性。
