Facile phthalocyanine doping into PEDOT leads to highly efficient and stable inverted metal halide perovskite solar cells†
Nickel phthalocyanine (NiPcS4) was doped into PEDOT:PSS to act as a very efficient hole transporting layer (HTL) for inverted perovskite solar cells (PSC). The PCE (power conversion efficiency) can reach up to 19.0% depending on the ratio of the two components. The PCE for the doped HTL is significantly higher than those for the individual components, i.e., 16.47% and 9.29% for PEDOT:PSS and NiPcS4, respectively. The stability of the PSCs was also significantly improved in air. UPS, AFM, SEM, and optical spectra studies revealed the following factors contributing to the improvement in PCE of the modified PSCs: (1) enhanced photon absorption; (2) improved film quality of perovskite; (3) enhanced hole transporting; (4) increased cell stability; and (5) enhanced work function of HTL. These results suggest that the phthalocyanine–PEDOT composites can be good hole transporting materials.