Mechanisms of Yb3+ sensitization to Tm3+ for blue upconversion luminescence in fluorophosphate glass

The sensitization mechanisms of Yb3+ to Tm3+ for the blue upconversion luminescence in fluorophosphate glass were studied. Two different mechanisms exist in the sensitization. One is the sequential sensitization that Tm3+ is excited from H-3(6) to (1)G(4) through absorbing three photons transferred from Yb3+ one by one. Another is the cooperative sensitization that two Yb3+ ions form a couple cluster firstly, and then the couple cluster Yb3+ ions transfer their energy to Tm3+ and excite it to (1)G(4). With the increment of the concentration of Yb3+ ions, the sequential sensitization becomes weak and the cooperative sensitization becomes intense, and the transformation trend of sensitization mechanism with the increment of Yb3+ concentration can be clarified by the introduction of Th3+ ions in the glass. (c) 2006 Elsevier B.V. All rights reserved.

LUMINESCENCE OF DY3+ ENHANCED BY SENSITIZATION

Four types of sensitized luminescence of Dy3+ are reported: (1) by a host having a broad-band spectrum as in Na3Y0.99Dy0.01(VO4)(2); (2) by a sensitizer having a broad-band spectrum as in Ca2B2O5:Dy3+, Bi3+; (3) by a sensitizer having a narrow-band spectrum as in Mg2Gd7.9Dy0.1(SiO4)(6)O-2; (4) by a sensitizer having a broad-band spectrum and energy migration as in Gd compounds such as Ca1.96Pb0.04Gd7.9Dy0.1(SiO4)(6)O-2. The luminescent intensity of Dy3+ can be enhanced in these ways.