Excitation‐dependent energy transfer and color tunability in Dy <sup>3+</sup> /Eu <sup>3+</sup> co‐doped multi‐component borophosphate glasses
R. Ramaraghavulu, K. Pavani, P.C. Nagajyothi, Jaesool Shim
Abstract
Abstract Using the melt‐quench technique, potassium zinc borophosphate (KZnBP) glasses incorporated with Dy 3+ , Eu 3+ , and Dy 3+ /Eu 3+ ions individually and combinedly were prepared, and their photoluminescence (PL)‐related features were investigated. The KZnBP glass containing an optimized content of Dy 3+ (0.5 mol%) is co‐doped with Eu 3+ in various contents, and the energy transfer (ET) process between them was studied at λ exci = 349, 364, 387 (Dy 3+ ), and 394 nm (Eu 3+ ). The Dy 3+ /Eu 3+ co‐doped system, when excited with Dy 3+ excitations has resulted in a significant decrease in the intensity of Dy 3+ peaks observed at 480 nm ( 4 F 9/2 → 6 H 15/2 , blue) and 574 nm ( 4 F 9/2 → 6 H 13/2 , yellow), with simultaneous enhancement of the intensity of Eu 3+ peaks at 591 nm ( 5 D 0 → 7 F 1 , orange) and 617 nm ( 5 D 0 → 7 F 2 , red). This trend is due to the efficient energy transfer from Dy 3+ to Eu 3+ , indicating that Eu 3+ ions were sensitized by Dy 3+ ions. Dexter's theory and the Inokuti–Hirayama (I–H) model revealed that the dipole–dipole interaction is accountable for the energy transfer from Dy 3+ to Eu 3+ through energy‐transfer channels [ 4 F 9/2 (Dy 3+ )+ 7 F 1,2 (Eu 3+ )→ 6 H 15/2 (Dy 3+ )+ 5 D 2 (Eu 3+ )] and [ 4 F 9/2 (Dy 3+ )+ 7 F 0 (Eu 3+ )→ 6 H 13/2 (Dy 3+ )+ 5 D 0 (Eu 3+ )]. The color coordinates of the Dy 3+ /Eu 3+ co‐doped glasses under various excitations fall within the white light emission spectrum, indicating their potential application in warm white LEDs.