▎ 摘　　要

Graphene oxide (GO) with single layer was moderately reduced at 200 degrees C for 4 h under N-2. Then the moderately reduced graphene oxide (rGO) water solution was employed as an additive to tune the properties of conventional poly(ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) solution. It's found that the incorporation of rGO into PEDOT:PSS nearly did not change its transparency, hydrophilic property, or the surface roughness. So, the rGO/PEDOT:PSS composite was used as a hole transport layer (HTL) to fabricate perovskite solar cells (PSCs). As a result, PSCs with rGO/PEDOT:PSS as HTL exhibit improved power conversion efficiency than that of PSCs with PEDOT:PSS as HTL. Our findings show that moderately reduced rGO/PEDOT:PSS could be an efficient HTL to improve power conversion efficiency of PSCs. (C) 2016 Elsevier B.V. All rights reserved.