Mo1.33C MXene-assisted PEDOT:PSS hole transport layer for high performance bulk-heterojunction polymer solar cells

Here we report the usage of two-dimensional MXene, Mo1.33C-assisted PEDOT:PSS as an efficient hole transport layer (HTL) to construct high efficiency polymer solar cells. The composite HTLs are prepared by mixing Mo1.33C and PEDOT:PSS aqueous solution. The conventional devices based on Mo1.33C:PEDOT:PSS exhibits average power conversion efficiency (PCE) of 9.2%, which shows 13% enhancement comparing to the reference devices. According to the results from hole mobilities, charge extraction probabilities, steady-state photoluminescence and atomic force microscope, the enhanced PCE can be ascribed to the improved charge transport and extraction properties of HTL, along with the morphological improvement of the active layer on top. This work clearly demonstrates the feasibility to combine advantages of Mo1.33C MXene and PEDOT:PSS as the promising HTL in organic photovoltaics.