A Cu3PS4 nanoparticle hole selective layer for efficient inverted perovskite solar cells

Abstract

Cu₃PS₄ nanoparticles are used as a new inorganic hole selective layer (HSL) to fabricate efficient perovskite thin-film solar cells in the inverted device configuration. Compared with other HSL materials used in efficient perovskite solar cells, Cu₃PS₄ has the smallest effective mass for holes. Additionally, Cu₃PS₄ has a valence band energy level of −5.05 eV, which is suitable for effectively extracting holes generated in perovskite absorbers. These reveal intrinsic properties of Cu₃PS₄ that make it an excellent HSL material for perovskite solar cells. We further find that a Cu₃PS₄ nanoparticle HSL promotes grain growth of perovskite thin films, which benefits device performance. Our perovskite solar cells using a Cu₃PS₄ nanoparticle HSL achieve a maximum power conversion efficiency of 18.17% with small hysteresis and a high fill factor of 81.6%, which is significantly better than the performance of the best control device using the poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) HSL.