Cross-relaxation and non-steady-state processes induced up-conversion color modulation in Gd 2 O 3 : Ln 3+ /Er 3+ (Ln = Tm, Ho)

Two efficient approaches based on cross-relaxation and non-steady-state upconversion processes were used to regulate the upconversion emission colors of Er3+ in Gd2O3 host, in which the cross-relaxation induced tunable up-conversion color of Er3+ was implemented via adjusting the doping concentration of Er3+ and co-doping Tm3+ and Ho3+. The corresponding energy transfer mechanism was elaborately investigated through down-conversion emission spectra and decay lifetimes. In addition, the influences of the excitation pulse-width of 980 nm laser on up-conversion emission color of Er3+ were also investigated on the basis of non-steady-state up-conversion processes. Results provide new insights into the influence of cross-relaxation and non-steady-state processes on the up-conversion luminescence, which endows up-conversion phosphor with the more opportunities to satisfy diverse applications by controlling its color output.