Device optimization of CsSnI2.95F0.05-based all-solid-state dye-sensitized solar cells with non-linear charge-carrier-density dependent photovoltaic behaviors

Abstract

Determining how the intrinsic kinetics of photo-generated charge carriers affect extrinsic photovoltaic performance is difficult yet essential work for the optimization of novel types of solar cells. However, contributions of several coexistent internal reactions can rarely be differentiated from one to another solely by means of experimental approaches. In this contribution, we propose the optimization of all-solid-state dye-sensitized solar cells by applying the inorganic hole-transport material (HTM) CsSnI_2.95F_0.05, experimentally focusing on enhancement of the interconnection between electrolyte precursor and the TiO₂ nanorod array. More importantly, by taking advantage of a physics-based device-level model that describes the diverse kinetics occurring among active TiO₂/dye/HTM junctions, we quantified the correlation between electrolyte precursor adsorbed onto the TiO₂ electrode and hole injection from dye to HTM. We attribute the significant impact of hole injection rate (k_hi) on non-linear charge carrier density-dependent photovoltaic response to one physical interpretation of experimental observations concerning abnormal photovoltaic responses following variable intensity illumination. Eventually, we achieved an average power conversion efficiency of approximately 7.7% over a large number of fabricated cells, the best one of which attained 9.8%.