Effects of 2-MeV Electron Beam Irradiation on the Physical Properties of Polyvinylalcohol-CdS and Polyvinylalcohol-CdS-2 Mercaptoethanol Nanoparticles

The effects of 2-MeV electron beam irradiation on the physical properties of polyvinylalcohol (PVA)-CdS and PVA-CdS-2 mercaptoethanol (2ME) nanoparticles (NPs) are reported, The NPs are prepared by using an aqueous chemical method with cadmium chloride and sodium sulfide as precursors, 2ME as capping material and PVA as a polymer matrix. They are irradiated with a 2-MeV electron beam at a dose of 20 kGy and 100 kGy. The optical absorption edge of the irradiated samples is red shifted with increasing dose from 20 kGy to 100 kGy and this red shift is attributed to an increase in the average particle size by irradiation with an electron beam. It is found from XRD that the crystalline structures of the NPs are profoundly affected by the electron beam irradiation. The PL emission spectra of the PVA-CdS NPs show two peaks, one at 471 nm and the other at 628 nm, which are attributed to band edge and surface defects of the NPs, respectively. The irradiation of the electron beam on PVA-CdS NPs leads to the quenching of surface-related emission. It is found from the SEM image that the surface of the irradiated PVA-CdS-2ME is composed of nanospheres (NSs) with an average size of about 300 nm and that the NSs are composed of CdS NPs with an average size of 4.6 nm.