Effect of trace Eu3+ doping on the luminescence intensity of LaGdO3:Tm3+, Yb3+ upconversion phosphors

Upconversion phosphors are materials capable of emitting visible light with higher energy than excitation light.In this study, trace amounts of Eu 3+ were doped into LaGdO3:Tm 3+ , Yb 3+ upconversion phosphors to investigate the resulting effects on luminescence intensity.Structural analysis confirmed that all samples maintained the LaGdO3 crystal structure with seven-fold coordination sites, regardless of Eu 3+ addition.The upconversion luminescence intensity decreased when the Eu 3+ concentration exceeded 10 -2 mol%, whereas an enhancement was observed in the range of 10 -3 to 10 -7 mol%.Notably, the luminescence intensity at the shorter wavelength end-which requires three-photon excitation-showed a more pronounced increase compared to the two-photon-excited luminescence.These results suggest that the luminescence of upconversion phosphors can be enhanced by optimizing intermediate relaxation during the multiphoton excitation process through appropriate trace doping.