Benzothieno[3,2‐b]thiophene‐Based Noncovalent Conformational Lock Achieves Perovskite Solar Cells with Efficiency over 24 %

Abstract Organic semiconductors with noncovalently conformational locks (OSNCs) are promising building blocks for hole‐transporting materials (HTMs). However, lack of satisfied neighboring building blocks negatively impacts the optoelectronic properties of OSNCs‐based HTMs and imperils the stability of perovskite solar cells (PSCs). To address this limitation, we introduce the benzothieno[3,2‐b]thiophene (BTT) to construct a new OSNC, and the resulting HTM ZS13 shows improved intermolecular charge extraction/transport properties, proper energy level, efficient surface passivation effect. Consequently, the champion devices based on doped ZS13 yield an efficiency of 24.39 % and 20.95 % for aperture areas of 0.1 and 1.01 cm 2 , respectively. Furthermore, ZS13 shows good thermal stability and the capability of inhibiting I − ion migration, thus, leading to enhanced device stability. The success in neighboring‐group engineering can triggered a strong interest in developing thienoacene‐based OSNCs toward efficient and stable PSCs.