Temperature dependent photoluminescence in Sol-gel derived Ce doped ZnO nanoparticles

Abstract

Abstract Undoped and Ce-doped ZnO nanoparticles (NPs) were prepared by sol–gel method. FTIR spectra demonstrated distinct characteristic absorption peaks at 520 and 528 cm−1 which correspond to Zn-O stretching mode, eventually confirming formation of ZnO. Other peaks corresponding to Zn-O-Zn antisymmetric vibrations at 628 and 668 cm−1 were also observed. UV–Vis transmission spectra showed absorption dips at 365 and 370 nm respectively for undoped and Ce doped ZnO and corresponding band gap values were estimated to be 3.32 and 3.28 eV. This redshift of band gap is due to the formation of a shallow levels inside the band gap. Photoluminescence (PL) emission spectra of NPs contained two major peaks one in UV and the other in the visible (blue) region. Their intensities monotonously rose and acquired substantially higher values with temperature lowering from 27⁰C to −10⁰C. The morphological study revealed the formation of hexagonal structures by Ce doping in ZnO. The study suggests the possibility of designing a temperature sensor using Ce doped ZnO also its potential use in organic photovoltaics.