Coupled ZnO–SnO<sub>2</sub> Nanocomposite for Efficiency Enhancement of ZnO–SnO<sub>2</sub>/p-Si Heterojunction Solar Cell
Rewrewa Narzary, Santanu Maity, Partha Pratim Sahu
Abstract
This article presents a low-cost fabrication of binary/coupled ZnO–SnO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> composite semiconductors for heterojunction solar cells using a simple and effective sol-gel approach. Here, the synthesis and characterization of coupled ZnO–SnO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> nanocomposites are carried out with varied stoichiometry designated as ZnO–SnO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> (20:80), ZnO–SnO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> (50:50), and ZnO–SnO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> (80:20). The X-ray diffraction (XRD) spectra confirmed an excellent crystalline domain in the order of ZnO–SnO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> (80:20) > ZnO–SnO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> (50:50) > ZnO–SnO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> (20:80). Nanorods formation of ZnO–SnO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> 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 ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${J}_{\text {sc}} = {18.83}$ </tex-math></inline-formula> mA/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text {oc}} = {0.581}$ </tex-math></inline-formula> V, and FF = 36.37) is determined using ZnO–SnO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> (80:20), which is almost twice of that of a single semiconductor-based Al/ZnO/p-Si/Al solar cell.