Physical properties of graphene doped Mn2O3 thin films for environmental application and solar cells simulation

Abstract

In the current report, graphene oxide (GO) doped dimanganese trioxide (Mn₂O₃) thin films were grown on glass substrates via spray pyrolysis method. The effect of doping concentration ratio (y = ([GO]/[Mn]) in the range of [0–8] at.-% by a step of 2 at.-%) on structural, morphological, optical and spectral properties was investigated. These physical studies were performed using X-ray diffraction, scanning electron microscopy (SEM), profilometry analysis, UV-VIS-NIR spectrophotometry and photoluminescence spectroscopy. It was found that graphene doping affects the properties of the layers, mainly structural and optical properties. In fact, structural analysis indicated that the best crytallinity was achieved at a doping concentration of about 4 at.-% with a crystallite size in the order of 87.01 nm. SEM images indicated that graphene doping leaded to higher roughness which improved the photocatalytic performance of the samples. Optical studies revealed a very low transmission in the visible range with direct band gap energy of around 1.43 eV, which is suitable for the use of Mn₂O₃:GO as absorber layer in solar cell devices. Refractive index (n) was, successfully, determined using Moss, Reddy and Ravindra models. PL spectra showed multiple emissions across both UV and visible regions. A high photodegradation efficiency of Malachite Green by graphene doped Mn₂O₃ thin films was detected. It was about 90 % under sunlight. The photovoltaic performance of ZnO/CdS/CIGS and ZnO/CdS/Mn₂O₃:GO/CIGS solar cells using one-dimensional Solar Cell Capacitance Simulator (SCAPS-1D) has been investigated, at the first time, to the best of our knowledge. It was found that the addition of Mn₂O₃:GO as a second absorber layer improves, significantly, the efficiency of the solar cell to reach 21.47 %.