Exploration of structural, optical, and photoluminescent properties of (1 – x)NiCo₂O₄/xPbS nanocomposites for optoelectronic applications

Abstract

(1-x)NiCo2O4/xPbS (0≤x≤0.2) nanocomposite samples were synthesized using the hydrothermal and thermolysis procedures. The different phases developed in the obtained nanocomposite samples were accurately determined using the x-ray diffraction technique equipped with a line-detector. The percentage of the formed phases (NiCo2O4 (NCO), PbS, PbSO4), structural and microstructure parameters were determined using Rietveld quantitative phase analysis. The transmission electron microscope (TEM) images and Rietveld analysis reveal almost isotropic particle size in the nano range with a very narrow size distribution. The obtained phase percentages of PbS and PbSO4 are smaller than nominated values (x) suggesting dissolving of some Pb and S ions in NCO which then confirmed by the analysis of Fourier-transform infrared (FTIR) spectra of nanocomposite samples. The absorption spectra are modified upon doping NCO with PbS. The optical band gaps of the nanocomposites increase as the amount of PbS is increased. The effect of alloying on extinction coefficient, refractive index, dielectric constant, optical conductivity, the intensity, and emitted color from the photoluminescence of the nanocomposite samples are also studied. The refractive index values of NCO and NCO-PbS nanocomposite samples exhibit normal dispersions. The photoluminescent measurements reveal that NCO-PbS nanocomposites could emit a violet color. The improvement in the values of the non-linear optical (NLO) parameters of pristine NCO at high frequencies or the nanocomposite samples at low frequencies, nominated them to be used in NLO photonic applications.