Tunable White Emission of Tm 3+ /Dy 3+ Co‐Doped Phosphate Glass and NaYP 2 O 7 Glass‐Ceramics for Solid‐State Lighting

ABSTRACT Tunable luminescent glass‐ceramics are promising materials for high‐power solid‐state lighting. In this work, Tm 3+ and/or Dy 3+ ‐doped Na 2 O–ZnO–Y 2 O 3 –B 2 O 3 –P 2 O 5 phosphate glasses were synthesized via a conventional melt‐quenching technique. The tunable emission, ranging from blue to white and subsequently to yellow–green, was achieved by adjusting the concentration of the activator Dy 3+ ion. The energy transfer mechanism from Tm 3+ to Dy 3+ was systematically analyzed using the Dexter theory and the Inokuti–Hirayama model. The optimal Dy 2 O 3 concentration was determined to be 1.0 mol%. Subsequently, NaYP 2 O 7 glass‐ceramics were obtained by heating treatment on the 1.0 mol% Tm 2 O 3 and 1.0 mol% Dy 2 O 3 co‐doped precursor glass, resulting in significantly enhanced photoluminescence intensity with an optimal crystallization condition of 675°C/4 h. Finally, WLED devices were further integrated by combining the prepared Tm 3+ /Dy 3+ co‐doped phosphate glass and glass‐ceramics with a 365 nm UV chip, producing cool white light with chromatic coordinates of (0.3362, 0.3619) and (0.3470, 0.3991), correlated color temperatures of 5360 and 5057 K, respectively. This research provides a viable pathway for the design of solid‐state lighting.