Thermally Stable D2h Symmetric Donor‐π‐Donor Porphyrins as Hole‐Transporting Materials for Perovskite Solar Cells

A series of new D2h symmetric porphyrins (MDA4, MTA4, and MDA8) with donor‐π‐donor structures have been synthesized as the hole‐transporting materials for perovskite solar cells (PSCs). The novel porphyrin molecules feature a D2h symmetrically substituted ZnII porphyrin core and two kinds of donor systems (diarylamine (DAA) and triarylamine (TAA)), which can regulate energy level, increase thermal stability, solubility, and hydrophobicity via long alkoxyl chains. PSC devices based on MDA4 as the HTM showed impressive power‐conversion efficiency (PCE) of 22.67 % under AM1.5G solar illumination. Notably, the device was sent for certification, and a PCE of 22.19 % was reported, representing the highest PCE from porphyrin‐based HTMs. Furthermore, the MDA4‐based PSCs showed excellent thermal stability under 60 °C and RH 60 % and preserved 88 % of initial performance after 360 hours. The strategy opens a new avenue for developing efficient and stable porphyrin HTMs for PSCs. New D2h symmetric porphyrin hole‐transporting materials were synthesized for high‐efficiency perovskite solar cells. The best device based on MDA4 with two diphenylamino groups directly attached to the porphyrin core exhibited a power conversion efficiency of 22.67 % (certified value of 22.19 %) with exceptional thermal stability. The novel strategy paves the way for efficient and stable PSCs with porphyrin HTMs.