摘要： Two-dimensional (2D) nanosheets have attracted enormous attention in photovoltaic devices owing to their outstanding photoelectric properties in recent years. Herein, 2D α-In2Se3 nanosheets with higher conductivity and suitable work function are synthesized by liquid phase exfoliation method. To ameliorate the low conductivity of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) (2.21×10-3 S cm-1), α-In2Se3 nanosheets are directly added into PEDOT:PSS to obtain PEDOT:PSS:α-In2Se3 composite film. The composite film exhibits excellent optical transmittance, suitable work function, and enhanced conductivity (1.54×10-2 S cm-1). To profoundly investigate the mechanism of conductivity improvement, XPS, Raman, EPR and AFM measurements are conducted. The results show that the synergistic effect of 2D α-In2Se3 nanosheets and isopropanol/deionized water cosolvent screens the Coulombic attraction among PEDOT and PSS. The screening effect results in the partial removal of PSS and the benzoid-quinoid transition of PEDOT. In addition, α-In2Se3 nanosheets may serve as physical linkers for PEDOT chains. Both effects are beneficial to increase interfacial contact area between PEDOT chains and form a larger conductive network of PEDOT, leading to an enhanced conductivity. The composite film is first employed as a hole transport layer (HTL) in polymer solar cells (PSCs). The power conversion efficiency (PCE) of PBDB-T:ITIC-based device with composite HTL is 10% higher than that of unmodified PBDB-T:ITIC-based device, and the maximum PCE of 15.89% is achieved in PM6:Y6 system. More interestingly, the stability of devices with composite HTL is improved owing to the partial removal of PSS. Thus the PEDOT:PSS:α-In2Se3 composite can be an application prospect HTL material in PSCs.