This paper describes the preparation and characterization of nanocrystalline Cd$_x$Pb$_{1-x}$S thin films by chemical bath deposition method with different Pb and Cd solute ratios. XRD, HRTEM and SAED patterns show the nanocrystalline nature of films with the co-existence of cubic, hexagonal and tetragonal phases, while micro-Raman spectra reveals the presence of cubic and hexagonal phases in the films. The average crystallite size of Cd$_x$Pb$_{1-x}$S estimated from TEM and XRD methods were nearly same. The chemical bonding present in the films was studied by FTIR spectral analysis. SEM images show uniformly distributed grains of different sizes over the substrates. Optical studies show the prominent blue shift in band gap energy ($E_g$) with the increase in Cd content in PbS. The increment of Cd addition to Cd$_x$Pb$_{1-x}$S has led to enhance the transmittance as well as band gap energy.

The Cd$_x$Pb$_{1–x}$S thin films with different concentrations of x from 0.2 to 0.8 were synthesized using the chemical bath deposition method. X-ray diffraction (XRD) and Williamson–Hall (W–H) plot gives the crystallite size that decreases with increased concentration. XRD, high-resolution transmission electron microscopy and selected area electron diffraction patterns of the film samples evidence the hexagonal phase structures of both CdS and PbS. Energy-dispersive X-ray confirmed the presence of Cd, Pb and S in the film samples. The transmittance of the film samples increases with the increase in concentration. Optical studies show the prominent blue shift in bandgap energy, whereas the Urbach energy decreases with the increased concentration x. The electrical conductivity of the films at room temperature is of the order of 10$^{–5}$ (${\Omega}$cm)$^{-1}$. The efficiency of the heterojunction cell structures Cd$_x$Pb$_{1–x}$S/CdTe and Cd$_x$Pb$_{1–x}$S/CdSe are calculated to be 3.37 and 2.21%, respectively.