Synthesis of Si NPs from River Sand Using the Mechanochemical Process and its Applications in Metal Oxide Heterojunction Solar Cells

Abstract

In this article, simple two-steps process for the synthesis of silicon nanoparticles (Si NPs) from river sand of Bangladesh and application of the synthesized Si NPs for the improvement of the performance of the metal oxide heterojunction solar cells (HJSCs) have been investigated. A modified aluminothermic reaction was performed to extract highly pure silicon from sand. Later, ultrasonication on the extracted silicon in hydrofluoric acid (HF) was done to synthesis Si NPs from extracted Si. Afterward, the prepared Si NPs were used to dope CuO absorber for the fabrication of CuO/ZnO heterojunction solar cell. Properties of extracted Si and its effect after doping in copper oxide (CuO) were studied by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX), X-ray Fluorescence (XRF), Fourier Transform Infrared Rays (FTIR), UV-Vis Spectroscopy, Raman and Photovoltaic study. Experimental results indicate that the extracted Si is polycrystalline in nature. The optical absorbance of CuO was enhanced significantly as a result of Si NPs doping and consequently, photoconversion efficiency was found to enhance more than 30% when Si NPs doped CuO was used in the Al/Si NP-CuO/ZnO/FTO heterostructure as a solar cell. This all spin-coated heterojunction solar cell showed a photoconversion efficiency of 1.16%. The photovoltaic responses reveal that the prepared Si NPs can be utilized for the improvement of the performance of HJSCs. This study on modified aluminothermically extracted Si NPs provide valuable insight and easy route for the preparation of Si NPs from sand and its applications in photovoltaic technology.