Structural and optical characteristics of laser irradiated CdSe/PVA nanocomposites

Abstract

Nanocomposites of polyvinyl alcohol (PVA) and Cadmium selenide (CdSe) were fabricated by ex-situ casting technique. CdSe nanoparticles were prepared by thermolysis under the flow of nitrogen. Rietveld refinement of x-ray data showed that the prepared CdSe adapts cubic zinc blend structure with a lattice parameter 6.057 Å and a mean grain size of 2 nm. Samples from CdSe/PVA nanocomposite have been exposed to infrared (IR) laser fluences in the range 0–19.6 J/cm2. The effect of IR laser radiation on the structural and optical properties of CdSe/PVA has been investigated using XRD and UV-vis spectroscopy. UV/VIS absorption spectra confirm the formation of hybridized film CdSe/PVA nanocomposite with refractive index in the range of 1.4119–1.8621 (at 700 nm). Also, the laser radiation reduces the optical energy gap from 4.1 to 3.43 eV which could be attributed to the increase in structural disorder of the irradiated CdSe/PVA nanocomposites due to the formation of coordination reaction between OH of PVA and CdSe nanoparticles. This means that the laser radiation led to a more compact structure of CdSe/ PVA nanocomposite and causes proper dispersion of CdSe nanoparticles in the PVA matrix. Further, the Commission Internationale de E’Claire (CIE units x, y and z) methodology was applied in this work for the description of colored samples. The color intensity DE, which is the color difference between the non irradiated sample and the irradiated ones, was increased from 11.40 to 30.57 with increasing the laser fluence up to 19.6 J/cm2.