Coupled ZnO–SnO2 Nanocomposite for Efficiency Enhancement of ZnO–SnO2/p-Si Heterojunction Solar Cell

摘要

This article presents a low-cost fabrication of binary/coupled ZnO–SnO ₂ composite semiconductors for heterojunction solar cells using a simple and effective sol-gel approach. Here, the synthesis and characterization of coupled ZnO–SnO ₂ nanocomposites are carried out with varied stoichiometry designated as ZnO–SnO ₂ (20:80), ZnO–SnO ₂ (50:50), and ZnO–SnO ₂ (80:20). The X-ray diffraction (XRD) spectra confirmed an excellent crystalline domain in the order of ZnO–SnO ₂ (80:20) > ZnO–SnO ₂ (50:50) > ZnO–SnO ₂ (20:80). Nanorods formation of ZnO–SnO ₂ has been confirmed through the scanning electron microscopy (SEM) micrograph. The improvement in photoconversion efficiency of solar cell from 3.39% to 3.98% was achieved due to increasing photo-excited free carrier generation with a significant change of nanorods dimensions. Furthermore, the UV–vis spectroscopy exhibited impressive transmittance of 85% in the wavelength range of 200–1000 nm. A bandgap modulation of 3.66–3.40 eV has been achieved. The power conversion efficiency (PCE) of 3.98 ( ${J}_{ext {sc}} = {18.83}$ mA/cm ^{2 , ${V}_{ext {oc}} = {0.581}$ V, and FF = 36.37) is determined using ZnO–SnO ₂ (80:20), which is almost twice of that of a single semiconductor-based Al/ZnO/p-Si/Al solar cell.}