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 nanoparticles were prepared by the ball milling technique and were doped with the neem leaf extract using the doctor blade 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 spectrophotometry, respectively. The SEM micrograph revealed significant change in the morphological structure of the sphalerite nanoparticles, which are not coarse, densely packed, well-formed flakes with uneven-edged crystalline structures. to a coarse, dispersed, grain-like crystalline structure after doping with neem leaf extract. The EDX confirmed the presence of zinc, sulfide, calcium, phosphorus, iron, chromium, and selenium and traces of other elements. UV-Vis Spectroscopy showed that the transmittance of both the doped and undoped sphalerite increased as the spectrum The wavelength moved from the ultraviolet region to the visible region at 94% and 88%, respectively, at the near-infrared region. The photon energy with respect to the refractive index of both doped and undoped sphalerite was found to be 1.66 eV–2.64 eV and 1.38 eV to 2.45 eV, respectively, which revealed that the doped sphalerite nanoparticle is beneficial for higher nonlinear optical response for optoelectronic devices. The band gap of the doped sphalerite nanoparticles was 2.52 eV, which is significantly better than the 3.63 eV 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.