Structural, thermal and optical characteristics of laser-exposed Pd/PVA nanocomposite

Abstract

Nanocomposite of polyvinyl alcohol (PVA) and nanosize palladium (Pd) were fabricated by ex situ casting technique. The fabricated Pd/PVA nanocomposite film has been exposed to infrared pulsated laser with fluences in the range 2–20 J/cm2. The effect of the laser radiation on the structural, thermal and optical properties of Pd/PVA has been investigated using XRD, TGA and UV–Vis spectroscopy. Exposure of IR laser radiation raises the refractive index from 1.84 to 3.38 at 700 nm which confirms the predominance of crosslinking process in the Pd/PVA nanocomposite. Furthermore, the reduction in the optical energy gap from 1.87 to 1.72 eV could be attributed to the increase in the structural disorder resulting from the coordination reaction between OH of PVA and Pd nanoparticles. The attained results reveal that the IR laser radiation enhances the dispersion of Pd nanoparticles in the PVA matrix resulting in more compact structure of Pd/PVA nanocomposite. Consequently, the onset temperature of decomposition increased upon laser irradiation. Commission Internationale de E’Claire (CIE units x, y and z) methodology was employed to describe the color of the studied samples. The color difference between the exposed nanocomposite films and the non-exposed one was raised from 5.63 to 12.01 as the laser fluence increases up to 20 J/cm2. Thus, the present study suggests that the IR laser radiation affects the microstructure of the Pd/PVA nanocomposite which in turn assists in tailoring the thermal and optical properties of such nanocomposite for usage in optoelectronics applications.