Phase evolution and PEC performance of ZnxCd(1−x)S nanocrystalline thin films deposited by CBD

Thin films of ZnxCd(1−x)S with varying Zn concentration, 0.1 ≤ x ≤0.9, were successfully deposited on stainless steel (SS) and amorphous glass substrate by simple and convenient chemical bath deposition (CBD) technique. Prepared films were annealed at 523 K for 1 h and used for structural, optical and morphological characterization. XRD studies confirm the nanocrystalline nature with cubic and hexagonal phases of CdS and ZnS, and diffraction peak intensity decreased with increase in x. The blue shift in the optical transmission spectra was found with increase in x. An interesting change in morphology, from flake to spherical particle structure, was observed with increase in Zn concentration. Electrochemical Impedance Spectroscopy (EIS) was carried out for all the films. These films were successfully utilized for photoelectrochemical (PEC) cell application. The charge transfer resistance (Rct) determined from nyquist plots were found to be decreased initially with increase in x, minimum for x = 0.5 and increased thereafter. The performance of PEC cell was found to be dependent on the concentration of Zn and efficiency was found to be increased with increasing x, maximum for x = 0.5 and decreased thereafter. The maximum short circuit current density (Jsc) and open circuit voltage (Voc) i.e. 457 μA/cm2 and 389 mV were respectively found for x = 0.5 under 10 mW/cm2 of illumination.