Efficient Perovskite Solar Cells Enabled by Facile Synthesis of Triphenylamine‐Based Hole‐Transport Material with D–A1–A2 Structure

Abstract

In perovskite solar cells (PSCs), the selection of the hole‐transport material (HTM) markedly influences both the achievement of high efficiency and overall stability. This study outlines the synthesis of a dopant‐free HTM founded on the donor–acceptor1–acceptor2 (D–A1–A2)‐conjugated structure and its integration into PSCs. The ensuing PSCs showcase a power conversion efficiency of 17.8%, comparable to NiOx inorganic HTM‐based devices and surpassing poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate polymeric HTM‐based devices. The efficiency comparable to NiOx is attributed to the efficient hole extraction and transport facilitated by the conjugated π junctions in the specifically designed structure. Furthermore, these devices exhibit enhanced stability, maintaining 95% of their initial performance for 60 d in an N2 atmosphere without encapsulation. The improved stability primarily arises from the hydrophobic nature of the HTM. The larger π‐conjugated molecules lead to a denser film by reducing intermolecular space, effectively retarding water intrusion and providing superior protection to the perovskite layer. Thus, the dopant‐free D–A1–A2 HTM with an extended conjugated π structure not only effectively enhances device efficiency but also substantially improves device stability.