Nanocrystal formation and photoluminescence in the Yb3+/Er3+ codoped phosphosilicate glasses

In the paper we show that the Yb³⁺/E^r3+ codoped transparent nanocrystal containing phosphosilicate glasses can be obtained by the melt-quenching devitrification approach. We find that the type of alkali oxides has a strong impact on the crystallization in phosphosilicate melts during cooling. The glasses exhibit high efficient up-conversion luminescence of Er³⁺ at 521, 545 and 655 nm under the 980 nm excitation. However, the trend of intensity change of the red emission with varying the crystal type and content is different from that of the green emission. We clarify how the Yb³⁺ → Er³⁺ energy transfer and the intensified distorted symmetry of local structure of active ions influence the up-conversion luminescence.