Optical absorption and Photoluminescence studies in Gamma-irradiated nanocrystalline CaF2

Abstract

Calcium fluoride (CaF2) nanoparticles were synthesized by co-precipitation method and characterized by powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM). Also, optical absorption (OA) and photoluminescence (PL) studies on gamma irradiated (γ-rayed) CaF2 nanoparticles were carried out. The XRD patterns confirmed the cubic crystallinity of the samples and the particle size was found to be ~25 nm. The purity of the synthesized nanoparticles was confirmed by FTIR spectrum. The morphological features studied using SEM revealed the agglomerated and porous nature of nanoparticles. γ-rayed CaF2 nanoparticles showed a prominent absorption with a peak at ~360 nm besides three weak but well separated absorptions at ~ 267, 442 and 510 nm. The various defect centers responsible for the absorption peaks were identified. The PL studies of samples showed strong emissions at ~396 nm and 425 nm. The observed PL emissions are attributed to defects created in nanocrystalline CaF2. © 2011 Pandurangappa C, et al.