In-doped ZnS nanoparticles: structural, morphological, optical and antibacterial properties

The present work deals with the effect of indium doping (0 ≤ x ≤ 0.10) on the structural, morphological, compositional and optical properties of the chemically synthesized Zn 1− x In x S nanoparticles. In addition, the antibacterial activity of Zn 1− x In x S nanoparticles is examined by the disc diffusion method. XRD results have revealed that In 3+ ions are successfully incorporated into the host ZnS structure and exhibit zincblende structure and the crystallite size is reduced with indium doping. FE-SEM displayed substantial variation in the spherical morphology of the ZnS nanoparticles with indium addition. EDX analysis identified the proportional amount of indium, zinc and sulphur elements, and the elemental mapping confirmed their distribution in the synthesized nanoparticles. The IR absorption peaks of functional groups present in Zn1−xInxS nanoparticles are studied using FTIR spectra, and the observed absorption bands between 700 cm −1 and 500 cm −1 are perceived for the characteristics Zn–S and In–S stretching modes. The optical absorption edge for all the samples is found to be blueshifted with respect to bulk ZnS, and strong quantum confinement is anticipated with the widening of band gap from 4.03 eV to 4.20 eV with indium doping. Furthermore, the pristine and doped Zn 1− x In x S nanoparticles are found to inhibit the growth of both gram-positive and gram-negative bacteria in the range of 20–100 µg/ml. Enhanced antibacterial activity is observed for Zn 1−x In x S nanoparticles with x = 0.10 as compared to other compositions. Besides, the optoelectronic perceptions are contingent on the evident variations in the optical properties and the antibacterial action of Zn 1− x In x S nanoparticles can be utilized in the drug-resistant challenges of the microbial world. Graphic abstract