Metal‐Free Phthalocyanine as a Hole Transporting Material and a Surface Passivator for Efficient and Stable Perovskite Solar Cells.

Perovskite solar cells in an n‐i‐p structure record high power conversion efficiency, but issues of insufficient thermal stability and the high cost of p‐type hole transporting materials have been raised as drawbacks. H2‐phthalocyanine (Pc) is introduced as a hole transport material to ensure the thermal stability and simultaneously have served surface passivation effects on hybrid halide perovskites as a Lewis base. Pyrrolic nitrogen in the Pc reacts with uncoordinated Pb2+ ions on the perovskite surface. Upon enhancing the interfacial interaction between phthalocyanine and the perovskite, the open circuit voltage in devices increases as compared to that of devices using a metal‐phthalocyanine complex. While the phthalocyanine‐applied device maintains superior thermal long‐term stability, the power conversion efficiency also exceeds 20%. [ABSTRACT FROM AUTHOR]