Effect of Eu3 + codoping on upconversion luminescence in Y2O3:Er3 +, Yb3 + nanocrystals

The influence of Eu3+ on the upconversion (UC) fluorescence of Er3+ in Y 2O3:Er3+, Y b3+ nanocrystals was investigated. Room-temperature UC spectra show that the intensity ratio of red to green lights was increased from 8.6 to 19.3 with 1.0 mol% Eu3+ doping. Additionally, with the increase of Eu3+ ion concentration, the nn values for both green and red UC emissions in Y 2O3:Er3+, Y b3+ nanocrystals become larger. Our analysis shows that the energy transfer between Eu3+ and Er3+ ions is the main cause for the enhancement of 2H11/2, 4S3/2→4F9/2 and 4I11/2→4I13/2 transitions of Er3+ ions.