Anti-thermal quenching luminescence and water resistance in Nd3+-doped Yb2M3O12 (M = Mo, W) phosphors and phosphor-in-glass composites

Lanthanide (Ln3+)-doped A 2 M 3 O 12 negative thermal expansion (NTE) materials have gained increasing interest owing to their ability to resist thermal quenching. However, several issues limit their practical application, such as a high hygroscopicity and a poor understanding of the influence of M-site cations on the luminescence thermal response. Herein, we synthesized and characterized 9 mol% Nd 3+ :Yb 2 Mo 3(1-x) W 3x O 12 phosphor powders and their corresponding phosphor-in-glass (PiG) composites. The results demonstrate that Yb2W3O12 exhibits superior NTE characteristics compared to Yb2Mo3O12, attributable to the weaker attractive energy of the W-O bond. Upon 980 nm excitation, the Nd3+: 4 F j -> 4 I 9/2 (j = 7/2, 5/2, 3/2) emissions significantly intensify with increasing temperature, especially in Nd3+:Yb2W3O12, which correlates with its higher phonon energy and enhanced NTE. Incorporating Yb2M3O12 (M = Mo, W) powders into a silicate glass matrix effectively improves the water resistance of the materials. Using the intensity ratio of the Nd3+: 4 F 7/2 -> 4 I 9/2 and Yb3+: 2 F 5/2 -> 2 F 7/2 transitions for optical thermometry, the PiG-Yb2W3O12 and PiG-Yb2Mo3O12 composites achieve maximum relative sensing sensitivities of approximately 4.52 and 3.88 %K-1, respectively, surpassing those of their pristine phosphor counterparts. These findings provide valuable insights for enhancing the performance of Ln3+-doped A2M3O12-type NTE materials.