The role of Mn2+ ions on structural, morphological, optical, electrochemical and antibacterial properties of Zn0.9Sn0.1S nanoparticles

A straightforward and economical co-precipitation technique was used to synthesize Zn 0.9-x Sn 0.1 Mn x S (x = 0.01, 0.03, 0.05) nanoparticles (NPs). By varying the Mn 2+ concentrations in the reaction solution, the antibacterial activity, electrochemical, optical, and structural properties of Zn 0.9-x Sn 0.1 Mn x S NPs. X-ray diffraction (XRD) analysis confirmed the formation of a cubic crystal structure, with the crystallite size showing a strong dependence on Mn 2+ incorporation. The Scherer’s method revealed that the crystallite size increased from 1.92 nm to 2.42 nm when the Mn 2+ doping percentage increased. The optical bandgap (E g ) decreased from 4.028 eV to 3.837 eV for the increase of Mn dopant. Electrochemical analysis revealed that the specific capacitance of pure Zn 0.9 Sn 0.1 S NPs was 159.30 mF g -1 at a scan rate of 80 mV s -1 . Upon Mn 2+ incorporation, the capacitance initially decreased to 111.09 mF g -1 at 1% doping but increased markedly to 227.47 mF g -1 and 246.71 mF g -1 at 3% and 5% Mn 2+ respectively. Photoluminescence (PL) spectra exhibited a prominent emission peak at 610 nm, with the PL intensity maximized at 1% Mn 2+ doping and quenched at higher concentrations. Antibacterial activity improved remarkably, with inhibition zones against E. coli (1.2–1.9 mm) and Streptococcus pneumoniae (1.5–2.3 mm). Mn 2+ -doped Zn 0 . 9 Sn 0 . 1 S NPs exhibited enhanced optical and antibacterial activity, with the optimum performance observed at 3% Mn 2+ doping.