Investigation of non-linear optical properties of CdS/PS polymer nanocomposite synthesized by chemical route

Abstract

Cadmium Sulfide (CdS) nanoparticles play an important role in non-linear optoelectronic devices. CdS/Polystyrene(PS) nanocomposite has been prepared by chemical ex-situ route and characterized by X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Ultraviolet-visible (UV-vis) and Photoluminescence (PL) spectroscopy. XRD spectra of CdS/PS nanocomposite reveals the cubic phase of CdS nanoparticles with average crystallite size ~2.54 nm. The vibrational band corresponding to Cd-S bond has been observed at 406.57 cm -1 in FTIR spectra of CdS/PS nanocomposite along the typical styrene bonds. Quantum confinement effect in the CdS/PS nanocomposite has been confirmed from the UV-vis spectra. In PL emission spectra, in addition to band to band transition emission, the green and yellow bands have been observed due to the interstitial sulfur and cadmium defect states respectively. Z-scan technique has been utilized to study the non-linear optical properties of the CdS/PS nanocomposite. The value of non-linear absorption coefficient (β) and non-linear refractive index (n 2) has been calculated. The large value of third order non-linear susceptibility is due to the quantum confinement effect plus the thermal lensing effect produced across the sample.