Synergized structural and optical features of ZnWO4/PbS heterostructure nanocomposites

Nanocomposite (1 - x)ZnWO4/xPbS ( x = 0, 0.05, 0.1, 0.15), samples have been synthesized through combining hydrothermal and thermolysis process. Synchrotron x-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Raman, diffused reflectance, and photoluminescence (PL) techniques were employed to explore the influence of varied quantities of PbS on the structure and optical properties of the synthesized nanocomposite samples. XRD Rietveld analysis revealed existence of PbS as a minor phase but with percent less than (x); large part of Pb and S ions were interstitially or substitutionally integrated into the ZnWO4 matrix. FTIR and Raman investigations authorized the integration of Pb and S ions within the ZnWO4 lattice. Utilizing the UV-visible diffuse reflectance spectra, the light absorption, extinction coefficient, refractive index, and nonlinear optical properties of ZnWO4 were examined in relation to PbS percent. The optical absorption of nanocomposites was significantly enhanced as the PbS content is raised, especially in the visible region. The nanocomposite samples exhibited optical band gap values of 4.05, 3.72, 3.71, and 3.39 eV for x = 0, 0.05, 0.1, 0.15 respectively. The refractive index of each sample was determined using various models based on their respective optical band gap values. As the PbS content increased, the nonlinear optical properties enhanced, and refractive index enlarged. Adding PbS to ZnWO4 causes the PL intensity to drastically quenched.