Photoluminescence, morphology and band gap in Europium-doped ZnS nanoparticles

Current study aims at synthesising Eu-doped ZnS nanoparticles by sol-gel co-precipitation and then characterising them for their structural, optical, and morphological features. Eu-doped ZnS NPs with doping levels of 1, 3, 5, and 7 at.% were synthesised. The characterisation tools such as XRD, UV-Vis, FTIR, photoluminescence and FESEM were employed to analyse their properties. Zinc blend phase with particle sizes lying in the range of 5.0 to 7.2 nm was confirmed by XRD. Eu-doped ZnS NPs show a band gap decrement at a higher level of doping. Defects induced UV and visible emission peaks were observed in photoluminescence emission spectra. Random-shaped particle-like structures that effectively have a persistent enlargement of size were seen in FESEM. The particle size was seen to monitor the band gap at higher doping levels. Eu doping was found to promote the growth of particle sizes which eventually resulted in decrement of the band gap.