Blue shift in band gap and photoluminescence of pulsed laser deposited SrS:Ce/quartz thin film nanophosphors

Abstract

We report on the synthesis of single phase SrS:Ce/quartz thin film nanophosphors at a substrate temperature of 400 degrees C using pulsed laser deposition. The AFM and FESEM micrographs reveal the island structure with granular growth of nanophosphors. The average crystallite size (similar to 13 nm using Williamson-Hall plot), the average grain size (similar to 40 nm using AFM) and the blue shift in band gap confirm the nanostructure formation. Interestingly, the photoluminescence emission corresponding to 5d-4f transitions in Ce3+ ion under the cubic crystal field of SrS also exhibits a significant blue shift, which can be explained using phenomenological crystal field model modified by covalency factor. (C) 2012 Elsevier B.V. All rights reserved.