Biosynthesis and characterization of zinc sulphide nanoparticles produced by the bacterium Lysinibacillus sp. SH74

ZnS, also known as zinc sulfide, is a highly significant compound semiconductor belonging to the II-VI group. It holds great potential for use in the fields of electronics and optoelectronics. In this research, the bacterium Lysinibacillus sp. SH74 was employed to synthesize ZnS nanoparticles through the l-cysteine desulfurization process. X-ray diffraction (XRD) analysis indicates that the ZnS produced by bacteria has a cubic crystal structure known as sphalerite. TEM images reveal that the nanoparticles in the size range from 3 nm to 5 nm. SAED analysis confirms that the ZnS synthesized by SH74 was polycrystalline. FTIR analysis suggests the presence of organic compounds on the surface of the bacterial ZnS nanoparticles. The fluorescence spectrum demonstrates that bacterial ZnS emits light in the wavelength range of 375–575 nm. The UV–visible spectrum exhibits a high absorption wavelength of the bacterial ZnS in the range of 268–319 nm, with a maximum of 294 nm. The bandgap width is determined to be 3.37 eV, indicating a significant red shift concerning the spectrum of bulk ZnS.