Up-conversion luminescence of Er^3＋ doped and Er^3＋/Yb^3＋ co-doped YTaO4

The synthesis and up-conversion luminescent properties of YTaO4：Er^3＋ and YTaO4：Er^3＋/Yb^3＋ are reported for the first time. According to the measurement results of up-conversion spectra, Yb^3＋ co-doping can remarkably enhance the green （^2H11/2/^4S3/2→^4I15/2） and red （^4F9/2→^4I15/2） emissions, but depress the infrared emission （^4I9/2→^4I15/2）. With the increase of the Yb^3＋ concentration, the intensity of green emission increases, after that, when the Yb^3＋ concentration increases continuously, the intensity of green emission decreases, while those of the red and infrared emissions increase and decrease alternately. In addition, the up-conversion mechanisms of Er^3＋ doped and Er^3＋/Yb^3＋ co-doped YTaO4 are also discussed. It is found that the transform of up-conversion mechanism from two-step energy transfer to cooperating sensitization takes place when Yb^3＋ concentration is increased up to 12 mol%. With the further increase of Yb^3＋ concentration, the energy-back-transfer gradually becomes the dominant up-conversion mechanism, which results in the quenching of the green emission and slight increasing of the red and infrared emissions.

Up-conversion luminescence of Er3+ doped and Er3+/Yb3+ co-doped YTaO4

The synthesis and up-conversion luminescent properties of YTaO₄:Er³⁺ and YTaO₄:Er³⁺/Yb³⁺ are reported for the first time. According to the measurement results of up-conversion spectra, Yb³⁺ co-doping can remarkably enhance the green (²H_11/2/⁴S_3/2→⁴I_15/2) and red (⁴F_9/2→⁴I_15/2) emissions, but depress the infrared emission (⁴I_9/2→⁴I_15/2). With the increase of the Yb³⁺ concentration, the intensity of green emission increases, after that, when the Yb³⁺ concentration increases continuously, the intensity of green emission decreases, while those of the red and infrared emissions increase and decrease alternately. In addition, the up-conversion mechanisms of Er³⁺ doped and Er³⁺/Yb³⁺ co-doped YTaO₄ are also discussed. It is found that the transform of up-conversion mechanism from two-step energy transfer to cooperating sensitization takes place when Yb³⁺ concentration is increased up to 12 mol%. With the further increase of Yb³⁺ concentration, the energy-back-transfer gradually becomes the dominant up-conversion mechanism, which results in the quenching of the green emission and slight increasing of the red and infrared emissions. Supported by the National Natural Science Foundation of China (Grant No. 10374011)