Performance Evaluation of 2D Material-Based Schottky Photovoltaics as Sustainable Indoor Light Energy Harvesters

This study investigates silicon (Si)- and indium phosphide (InP)-based photovoltaic (PV) devices featuring transparent two-dimensional (2D) Schottky electrodes for sustainable indoor light energy harvesting. Two structures—Graphene/n-Si and MXene/n-InP Schottky junctions—were numerically simulated under low-intensity indoor illumination. Performance was evaluated under four common artificial light sources: compact fluorescent (CFL), halogen (HALO), cold LED (C-LED), and warm LED (W-LED). The simulation results demonstrated a strong potential for both devices as indoor photovoltaics (iPVs), with fill factors exceeding 80% in all lighting conditions. The MXene/n-InP device achieved notably high efficiencies (up to 33.66% under HALO), while the Graphene/n-Si device reached 20.86% (HALO), surpassing their respective solar-optimized performance. The maximum power densities exceeded 40 µW·cm−2 (MXene/n-InP) and 20 µW·cm−2 (Graphene/n-Si) under all lighting conditions, highlighting their viability as cost-effective, high-performance iPVs capable of sustainably energizing Internet-of-Things (IoT) devices in smart buildings.