Efficient Sn-Pb Perovskite Solar Cells Through Inhibiting Hole Accumulation.

Yuan, Haobo; Li, Xiaodong; Zhang, Wenxiao; Hu, Yuyang; Xu, Jianhong; You, Tengyi; Weng, Qiang; Mao, Yunjie et al. · Adv Mater · 2025

basic_science · Level V

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Abstract

Sn-Pb perovskite solar cells (PSCs) own the highest theoretical efficiency due to their ideal bandgap. However, the efficiency of Sn-Pb PSCs remains 22-23% at present, which is much lower than Pb-based PSCs. One key reason lies in the Sn<sup>2+</sup> oxidation issue. Here, this study demonstrates that apart from well-known chemical environmental oxidation, photo-generated holes and their accumulation are also a critical factor for Sn<sup>2+</sup> oxidation in Sn-Pb PSCs. To address this issue, a non-planar hole transport layer (HTL) of P3CT/Me-4PACz is designed through solution micelle regulation. P3CT/Me-4PACz will form a 3D HTL film with a spike-like structure penetrating Sn-Pb perovskite bulk to accelerate hole extraction, thus inhibiting holes accumulation and Sn<sup>2+</sup> oxidation. Resulted Sn-Pb PSCs exhibit the highest efficiency of over 24% with good operational stability, retaining 82% of initial efficiency after continuous MPP tracking for 1000 h at an elevated temperature of 55 °C.