Study of the influence of Er/Ln co-doping in La2O3 thin films on their up-conversion properties (where Ln = Ho or Nd)

In this study we report significant enhancement of up-conversion emissions of La2O3:Er thin films when they are co-doped with Er/Ln (where Ln = Nd or Ho). The proposed mechanisms by which the Ln ions contribute to these emissions are based on different mechanistic routes. While the La2O3 samples co-doped with Er/Nd involves energy transfer Nd-III -> E-III processes, in the La2O3 samples co-doped with Er/Ho involves energy transfer Er-III -> Ho-III processes. All samples were synthesized by a solid state photochemical deposition method followed by a subsequent calcination process. The luminescent properties reveal that samples under 980 nm irradiation exhibit characteristic up-conversion emissions that are focused in the green region of the spectrum and that the nature of second activator (Ln) determines the degree of efficiency of these emissions.