ABSTRACT Sn‐Pb mixed perovskite solar cells (PSCs) have attracted broad attention due to their higher theoretical power conversion efficiency (PCE). However, organic materials, including poly (3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) are still commonly used as the hole transport layer (HTL) in this field, it leads to poor stability in Sn‐Pb mixed PSCs. In this work, we introduce a p‐type SnO x (0 < x< 2) as hole transport layer, boosting both the efficiency and stability of Sn‐Pb mixed PSCs. The unique successive hemispherical protrusions‐like morphology markedly improves the interfacial contact with the perovskite layer, resulting in enhanced carrier extraction, efficient transport and distinctive modulation of light absorption. Meanwhile, the perovskite crystallinity is greatly enhanced with suppressed oxidation of Sn(II), and the photovoltaic performance is greatly improved. Finally, we achieve a champion PCE of 23.71% for Sn‐Pb mixed PSCs, breaking the record for fully‐inorganic‐HTL‐based Sn‐Pb mixed PSCs. The device retains 90% of its initial efficiency after operating at the maximum power point for 1105 h, indicating a marked improvement in stability among the reports of best stability. This effective inorganic hole transport material provides a new research strategy for Sn‐Pb perovskite optoelectronic devices.
Shi et al. (Sun,) studied this question.