▎ 摘　　要

Combination of graphene (Gr) with semiconductor to form heterojunction solar cells has recently attracted significant attention due to its simple process with low cost. Here, we have reported a new structure of graphene-gallium arsenide (Gr-GaAs) solar cells using poly(3-hexylthiophene) (P3HT) as hole transport layer. It is found that the open-circuit voltage (V-oc) and short-circuit current (J(sc)) of the solar cells get significantly increased due to the introduction of P3HT layer. Initial power conversion efficiency (PCE) of 6.84% can be obtained for the Gr-GaAs solar cell with a P3HT layer. The performance improvement of the Gr-GaAs solar cell with a P3HT layer is strongly associated with its small saturation current, due to the increase of built-in barrier and the reduction of the carrier recombination at the Gr-GaAs interface. By doping Gr via bis(trifluoromethanesulfonyl)-amide (TFSA) and utilizing an efficient TiO2 antireflective film (AR film), the PCE of the solar cell with a P3HT layer can reach a maximum value of 13.7%, which is the highest value achieved for the Gr-GaAs solar cells so far. These results pave a new way for the fabrication of high efficiency Gr-GaAs solar cells. (C) 2015 Elsevier Ltd. All rights reserved.