Influence of Eu doping on the microstructure and photoluminescence of CdS nanocrystals

The CdS:Eu nanocrystals with a strong white emission have been synthesized by solvothemal method using ethylene glycol as solvents. From X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM) analysis it was observed that the average diameter of the CdS:Eu nanocrystals is about 5 nm. The traces of groups adsorbed on CdS:Eu nanocrystals were confirmed via FT-IR spectra. UV–visible spectroscopy study was carried out to determine the band gap of the nanocrystals and the absorbance peaks showed blue shift with respect to the bulk CdS. From photoluminescence (PL) studies at λex = 398 nm, the PL emission intensity of CdS:Eu nanocrystals enhanced by doping Eu3+ ions. In addition, the synthesis parameters including the concentration of doped Eu3+ ions, the reaction time, and the reaction temperature have influence on the optical properties of CdS:Eu nanocrystals. The charge compensation agent is a decisive factor for PL emission intensity of CdS:Eu nanocrystals. Furthermore, the storage time and condition on the fluorescence of CdS:Eu nanocrystals were also investigated.