Morphological, Elemental and Optical, Properties of Sphalerite Nanoparticle (ZnS) Doped with Neem Leaf Extract

This study investigated the properties of undoped Sphalerite nanoparticles and Neem leaf extract doped Sphalerite nanoparticles. The Sphalerite nanoparticle were prepared by ball milling technique and was doped with the Neem leaf extract using Doctors Blades method. The Morphological, elemental and optical properties of the nanoparticles were investigated using scanning electron microscopy (SEM), energy dispersed X-ray analysis (EDX), and UV spectrophotometer respectively. The SEM micrograph revealed significant change in the morphological structure of the Sphalerite nanaoparticle from being coarse, densely packed, well-formed flakes with uneven edged crystalline-structured to coarse, dispersed, grain-like crystalline structure after doping with Neem leaf extract. The EDX confirmed the presence of zinc, sulphide, calcium, phosphorous, iron, chromium, and selenium and trace of other elements. UV-Vis spectroscopy showed that the transmittance of both the doped and undoped Sphalerite increased as the spectrum wavelength moved from ultraviolet region to visible region at 94% and 88% respectively at the near-infrared region. The photon energy with respect to refractive index of both doped and the undoped Sphalerite was found to be 1.66eV – 2.64eV and 1.38eV to 2.45eV respectively which revealed that the doped Sphalerite nanoparticle is beneficial for higher non linear optical response for optoelectronic devices. The Bang gap of the doped Sphalerite nanoparticles was 2.52eV which is significantly better than 3.63eV obtained in undoped Sphalerite. This suggested that the Neem leaf extract introduced necessary impurities which enhanced the optoelectronic properties of the Sphalerite nanoparticles. Hence, Neem leaf-doped Sphalerite nanoparticles can be a potential enhanced material for optoelectronic devices with excellent performance in photovoltaic applications.