Re-Dispersible Li⁺ and Eu³⁺ Co-Doped Nanocrystalline ZnO: Luminescence and EPR Studies

Abstract

Nano-crystals of ZnO, Eu3+ doped ZnO, and Li+, Eu3+ co-doped ZnO have been prepared by urea hydrolysis in ethylene glycol medium at 150 degrees C. Ethylene glycol acts as capping agent for nanoparticles. Three colors 437 (blue), 540 (green) and 615 nm (red) from 2 at.% Li+ and 5 at.% Eu3+ co-doped ZnO have been observed from luminescence studies compared to that from 5 at.%. Eu3+ doped ZnO, which shows emission at 437 and 615 nm. It is established that green light is originated from the oxygen vacancy brought by Li+ incorporation into ZnO. Particles are redispersible in organic solvent such as ethanol, and are able to incorporate into polymer-based material such as SiO2 matrix.

Observation of intermediate bands in Eu3+ doped YPO4 host: Li+ ion effect and blue to pink light emitter

“…In this study, absorption intensity in ∼340-350 nm is very high and also intensity of Eu-O 4 and ZnO. 29,43 In overall, Li + doping improves absorption intensity.…”

Luminescence Properties of Redispersible Tb3+‐Doped GdPO4 Nanoparticles Prepared by an Ethylene Glycol Route

“…Peaks at 1662 and 3310 cm -1 correspond to bending and stretching vibrations, respectively, for the O-H group of the ethylene glycol molecule, which is used as a capping agent for nanoparticles. [27,[29][30][31][32] However, free O-H has a stretching frequency at 3650 cm -1 . [23] The broad band at 3310 cm -1 therefore indicates the presence of a hydrogen bond in ethylene glycol molecules.…”

“…The peaks at 2856 and 2927 cm -1 correspond to the stretching vibrations of the CH 2 group of the ethylene glycol molecule, whereas its bending vibration (scissoring) is observed at 1460 cm -1 . [27,[29][30][31][32] The peak at 2362 cm -1 is due to absorption of CO 2 gas from the atmosphere on the surface of particles. The IR study suggests the presence of ethylene glycol along with nanoparticles and thus will help in the incorporation of nanoparticles in polar media.…”

Energy transfer process and optimum emission studies in luminescence of core–shell nanoparticles: YVO4:Eu–YVO4 and surface state analysis

“…It has been reported that the efficient luminescence of Eu 3+ ion can be obtained from Eu 3+ doped Y 2 O 3 [36,37], SiO 2 [38], TiO 2 [39], SnO 2 [40], and ZnO [41,42], on excitation through Eu-O charge transfer process at ∼250 nm. However, in Eu doped YVO 4 , there are two processes such as V-O charge transfer (from VO 4 3− ) and…”