Analytical Modeling and Design Optimization of High‐Performance ZnO‐Nanowire/CuO‐Thin Film/p⁺‐Si Multi‐Junction Solar Cells

In the current work, an optimized design window for the indium tin oxide (ITO)/n‐ZnO‐nanowire (NW)/p‐CuO‐thin film/p + ‐Si multi‐junction solar cells is provided for achieving high power conversion efficiency (PCE). The requisite model has been developed using the drift‐diffusion approach and validated against existing experimental data. The effects of various design parameters are thoroughly investigated and optimized to achieve higher PCE. Initially, by optimizing the lengths of ZnO NWs and the thickness of CuO films, a PCE of 22% is achieved. To enhance the PCE further, ZnO NWs are doped with cobalt (Co) (0–15%), and the CuO thin film is doped with graphene (Gr) (0–10%), independently. The impact of annealing of the top‐ITO layer on PCE has also been studied without any doping. Finally, optimizing the geometric parameters of ZnO‐NW (length of 200 nm), CuO thin film (thickness of 350 nm), doping concentrations of Co (5%) and Gr (5%), and the annealing temperature of ITO (450 °C), PCE of the proposed n‐ZnO‐NW/p‐CuO‐thin film/p + ‐Si multi‐junction solar cell is obtained to be ≈40%. Thus, in this work, a comprehensive set of design parameters for ZnO‐NW/CuO‐thin‐film/Si‐based solar cells is provided to achieve high PCE.