Effect of concentration of trisodium citrate complexing agent on spray-synthesized ZnS thin films

Here, we present the effect of molar concentration of trisodium citrate complexant on the solid state attributes of zinc sulphide (ZnS) thin films grown using chemical spray pyrolysis (CSP). The films were synthesized using 0.1 M concentration of ZnCl2, 0.1 M concentration of thiourea with addition of 0.01 M, 0.02 M and 0.03 M concentrations of trisodium citrate complexant at 300 °C. The films’ transmittance, band gap, and refractive index are from 55.81% to 82.44%, 3.52 to 3.72 eV and 3.07 to 4.02 respectively. The films possessed cubic and microcrystalline/amorphous structures. The crystallite size of the film deposited with 0.01 M trisodium citrate concentration was 20.454 nm. The surface morphology exhibited separate standing nanodot-like and nanorod-like crystals with increasing molar concentration. Raman spectroscopy revealed CC bond. The Fourier transform infrared (FTIR) spectroscopy showed various bonds inherent in the film with an attendant band edge emissions arising from the photoluminescence (PL) studies. The contact angle disclosed the films’ hydrophilic surface characteristics.