Origin of near to middle infrared luminescence and energy transfer process of Er3+/Yb3+co-doped fluorotellurite glasses under different excitations

摘要

We report the near to middle infrared luminescence and energy transfer process of Er3+/Yb3+ co-doped fluorotellurite glasses under 980, 1550 and 800?nm excitations, respectively. Using a 980?nm laser diode pump, enhanced 1.5 and 2.7?μm emissions from Er3+:I_13/2→4I_15/2 and I_11/2→4I_13/2 transitions are observed, in which Yb3+ ions can increase pumping efficiency and be used as energy transfer donors. Meanwhile, Yb3+ can also be used as an acceptor and intensive upconversion luminescence of around 1000?nm is achieved from Er3+:I_11/2→4I_15/2 and Yb3+: F_5/2→4F_7/2 transitions using 1550?nm excitation. In addition, the luminescence properties and variation trendency by 800?nm excitation is similar to that using 1550?nm excitation. The optimum Er3+ and Yb3+ ion ratio is 1:1.5 and excess Yb3+ ions decrease energy transfer efficiency under the two pumpings. These results indicate that Er3+/Yb3+ co-doped fluorotellurite glasses are potential middle- infrared laser materials and may be used to increase the efficiency of the silicon solar cells.