Comparative Investigation on Upconversion Luminescence Properties of Lu2O3:Er/Yb and Lu2O2S:Er/Yb Phosphors

A series of (Lu0.99-xEr0.01Ybx)(2)O-3 and (Lu0.99-xEr0.01Ybx)(2)O2S (x = 0-0.1) phosphor particles are prepared to investigate their upconversion luminescence properties. Under 980 nm pumping laser, the two phosphors both exhibit strong green emission at approximate to 520-573 nm and weak red emission at approximate to 648-688 nm arising from S-4(3/2)/H-2(11/2)-> I-4(15/2) and F-4(9/2)-> I-4(15/2) transitions of Er3+, respectively. The optimum concentrations of Yb3+ sensitizers are found to be 1.0 at% in oxide and 0.5 at% in oxysulfide, and their corresponding CIE chromaticity coordinates are (0.29, 0.69) and (0.33, 0.65). The Lu2O2S:Er/Yb phosphor exhibits approximate to 42 times higher luminescence intensity than the Lu2O3:Er/Yb contrast. More Yb3+ addition further increases the proportion of red emission by the cross-relaxation between adjacent Yb3+ and Er3+ and the multiphonon relaxation. The luminescence intensities of the two phosphors gradually increase as the laser output power increases and the upconversion mechanisms are both identified to be two-phonon processes. The Lu2O2S:Er/Yb phosphor has a shorter lifetime than the Lu2O3:Er/Yb counterpart, whereas the lifetime for the red emission is longer than that for the green emission in each case.

Automated summary

A series of phosphor particles doped with different concentrations of Yb3+ were studied, showing strong green and weak red emissions. The optimal concentrations of Yb3+ were determined to be 1.0 at% in oxide and 0.5 at% in oxysulfide, with the Lu2O2S:Er/Yb phosphor exhibiting significantly higher luminescence intensity.