Analysis of Eu3+ Emission from Mg2TiO4 Nanoparticles by Judd-Ofelt Theory

摘要

Eu3+ doped Mg-2 TiO4 (2 at% of Eu) nanoparticles which are 5 to 10 nm in diameter are prepared by Pechini-type polymerized complex route followed with the calcination in the temperature range from 400 degrees C to 700 degrees C. Emission spectra display characteristic D-5(0) -> F-7(J) (J = 0, 1, 2, 3, and 4) spin forbidden f-f electronic transitions of the Eu3+ ions with the most pronounced emission coming from D-5(0) -> F-7(2) transition and with the emission decays varying between 0.57 and 0.87ms for samples prepared at different temperatures. Judd-Ofelt theoretical analysis of the emission spectra of Eu3+ ions was performed, which allowed calculating radiative and nonradiative emission probabilities, Judd-Ofelt intensity parameters, and the quantum efficiency of the Eu3+ emission in the Mg-2 TiO4 nanoparticles. The analyses showed the existence of high asymmetry around the metal ion sites. Also, the largest quantum efficiency of emission of 58.5% is found in nanoparticles prepared at 600 degrees C.