Investigation on the charge transfer excitation spectrum for nano-sized Y2O3:Eu3+

In the harmonic oscillator mode of an optical center in charge transfer (CT) excitation, the vibration frequency ω (in ground state) and ω′ (in CT state) would be decreased in nano-sized Y2O3:Eu3+, leading to the shrinkage in energy span Espan of CT excitation spectrum. The decrease of ω′ results in the decrease of vibration energy Evib of an optical center obtained in CT excitation. In addition, the zero-phonon CT energy Ezp is decreased with the decrease of phosphor size in nano-scale. Based on the changing magnitudes in Ezp and Evib, the change in CT energy ECT was obtained, which is basically consistent with that measured in the experiment.