Solution-processed Graphene-MoS2 heterostructure for efficient hole extraction in organic solar cells

Abstract

A major bottleneck exploiting the unique electronic properties of two-dimensional materials like graphene is the lack of mass production methods that are able to produce van der Waals heterostructures. Here, we prepare Graphene-molybdenum disulfide (MoS2) heterostructures via liquid-phase exfoliation followed by hydrothermal reaction, and employ Graphene-MoS2 hybrid thin films as the hole extraction layer in PTB7-Th:PC71BM organic solar cells. We demonstrate a maximum power conversion efficiency of 9.5% whilst retaining more than 93% of the initial efficiency over a storage period of 1000 h, surpassing current reported two-dimensional materials based devices. Our results represent the great potential of two-dimensional heterostructures as hole extraction materials for efficient and stable photovoltaics devices.