Device modeling of two-dimensional hole transport materials for boosting the performance of non-fullerene acceptor bulk heterojunction organic solar cells

Simple and low-cost two-dimensional (2D) materials are of great interest considering their wide use in various device applications. Here, we present the application of 2D materials, i.e., graphene oxide (GO), molybdenum disulfide (MoS2), and tungsten disulfide (WS2) as hole transport layer (HTL) in non-fullerene acceptors (NFAs) organic photovoltaics (OPVs) using device simulation. The numerical simulation was carried out using SCAPS-1D and specifically focused on the effect of thickness and defect density at the active layer on the photovoltaic characteristics of the devices. In addition, the influence of defect density at the HTL/active layer interface on the device performance was also studied. After conducting a series of optimization, an optimum power conversion efficiency (PCE) of 15.89%, 20.05%, and 23.55% was achieved for NFA-based OPV with GO, MoS2, and WS2, respectively. This work provides a practical explanation of the feasible performance enhancement and critical design parameters for OPV devices. The results showcase the potential application of 2D materials as low-cost HTL for high-efficiency organic solar cells.