A study on optical, photoluminescence and thermoluminescence properties of ZnO and Mn doped-ZnO nanocrystalline particles

Pure ZnO and Mn (1%wt.) doped-ZnO nanocrystalline particles were synthesized by reverse micelle method. The structural properties of the nanoparticles were investigated by X-Ray Diffraction (XRD) and Transmission Electron Microscopy (TEM) techniques. UV-vis and photoluminescence (PL) spectroscopy was used for analyzing the optical properties of the nanoparticles. XRD and TEM results revealed the formation of ZnO and Mn doped-ZnO nanocrystalline particles with pure wurtzite crystal structure and average particle size of 18-21 nm. From UV-vis studies, the optical band gap energy of 3.53 and 3.58 eV obtained for ZnO and Mn doped-ZnO nanoparticles, respectively. Further optical analysis showed that the refractive index decreases from 2.35 to 1.35 with the change of wavelength. Room-temperature photoluminescence analysis of all samples showed four main emission bands including a strong UV emission band, a weak blue band, a week blue-green band, and a weak green band which indicated their high structural and optical quality. Moreover, the samples exposed to gamma rays sources of Cs-137 and Co-60 and their thermoluminescence properties were investigated. The thermoluminescence response of ZnO and Mn doped-ZnO nanocrystalline particles as a function of dose exhibited good linear ranges, which make them very promising detectors and dosimeters suitable for ionizing radiation. (C) 2013 Elsevier GmbH. All rights reserved.