Boosting the performance and stability of perovskite solar cells with phthalocyanine-based dopant-free hole transporting materials through core metal and peripheral groups engineering

Three novel dopant-free hole-transporting materials (HTMs) based on phthalocyanine core containing (4-methyl formate) phenoxy or (4-butyl formate) phenoxy as the peripheral groups with cupper or zinc as the core metals (CuPcNO 2 -OMFPh, CuPcNO 2 -OBFPh, ZnPcNO 2 -OBFPh) were designed and synthesized. All of the phthalocyanine complexes show excellent thermal stabilities, appropriate energy levels and suitable hole mobilities. The potential of three HTMs were tested in perovskite solar cells (PSCs) and ZnPcNO 2 -OBFPh based PSC obtained power conversion efficiency (PCE) of 15.74% under 100 mA cm −2 standard AM 1.5G solar illumination. Most important of all, PSC based on ZnPcNO 2 -OBFPh shows better stability than that of the other two phthalocyanines and Spiro-OMeTAD under continuous light irradiation at 60 °C and maximum power point tracking in ambient air without encapsulation after 500 h. The results show that the introduction of appropriate peripheral groups and core metals can improve the performance and stability of PSCs dramatically, which provides an alternative way to develop HTMs for efficient and stable PSCs.