Corannulene-based hole-transporting material for efficient and stable perovskite solar cells

Summary Core structures with linear, planar, and spiral conformations have been designed as triphenylamine (TPA)-based hole-transporting materials (HTMs), which are the most prevalent small molecular HTMs in perovskite solar cells (PSCs). However, most of the reported TPA-based HTMs cannot achieve sufficient balance between efficiency and stability, which is governed by core structures. Herein, a sym-penta(N,N-bis(4-methoxyphenyl)aniline)corannulene (cor-OMePTPA) featuring a corannulene core and five TPA peripheral arms is designed as alternative HTM. Planar negative-intrinsic-positive (n-i-p) PSCs with cor-OMePTPA exhibit champion efficiencies of 20% and maintain 86% of their initial performances for more than 1,000 h after thermal annealing at 60°C. Compared with spiro-OMeTAD, cor-OMePTPA-based PSCs show slightly lower efficiencies but much better thermal stabilities. The main merit of cor-OMePTPA lies in its bimolecular interpenetration capability with noncovalent interactions to modulate the HTM configurations from single-molecular curvature to bimolecular planarity, thereby providing promising opportunities to achieve excellent balance between efficiency and stability.