In doping effect on the structural, morphological, optical and enhanced antimicrobial activity of facilely synthesized novel CuS nanostructures

In this paper, we report the impact of Indium on the structural, morphological, optical, and antibacterial properties of copper sulfide (CuS) nanoparticles produced by facile chemical Co-precipitation process. X-ray diffraction, Raman, scanning electron microscope and X-ray photoelectron spectroscopy techniques were used to investigate the phase composition and purity. Antibacterial tests were performed by well diffusion method and growth kinetics assay. The hexagonal structure of CuS nanoparticles is revealed by XRD/Raman analysis, with crystallite size ranging from 6 to 11 nm. SEM pictures also revealed a larger crystallite size with the addition of indium doping. For maximum indium doping (5 wt.%), the morphology was modified from nanoparticle to nanosheet. The existence of indium dopant was also confirmed by XPS analysis. The energy band gap shifted from 2.16 - 2.47 eV with altering indium concentrations in CuS. Indium doped CuS NPs exhibited highest antibacterial effect against Mycobacterium smegmatis (20-24 mm) while Pseudomonas aeruginosa had the lowest antimicrobial activity (12-14 mm). Growth kinetics study delineated that In:CuS had high antibacterial efficacy against all the tested microbial strains and suppress the microbial growth in the logarithmic growth phase. Hence, In:CuS might be applied as antimicrobial coatings to inhibit microbial biofilm development.