Excitation‐dependent energy transfer and color tunability in Dy³⁺/Eu³⁺ co‐doped multi‐component borophosphate glasses

Abstract

Using the melt‐quench technique, potassium zinc borophosphate (KZnBP) glasses incorporated with Dy3+, Eu3+, and Dy3+/Eu3+ ions individually and combinedly were prepared, and their photoluminescence (PL)‐related features were investigated. The KZnBP glass containing an optimized content of Dy3+ (0.5 mol%) is co‐doped with Eu3+ in various contents, and the energy transfer (ET) process between them was studied at λexci = 349, 364, 387 (Dy3+), and 394 nm (Eu3+). The Dy3+/Eu3+ co‐doped system, when excited with Dy3+ excitations has resulted in a significant decrease in the intensity of Dy3+ peaks observed at 480 nm (4F9/2→6H15/2, blue) and 574 nm (4F9/2→6H13/2, yellow), with simultaneous enhancement of the intensity of Eu3+ peaks at 591 nm (5D0→7F1, orange) and 617 nm (5D0→7F2, red). This trend is due to the efficient energy transfer from Dy3+ to Eu3+, indicating that Eu3+ ions were sensitized by Dy3+ ions. Dexter's theory and the Inokuti–Hirayama (I–H) model revealed that the dipole–dipole interaction is accountable for the energy transfer from Dy3+ to Eu3+ through energy‐transfer channels [4F9/2(Dy3+)+7F1,2(Eu3+)→6H15/2(Dy3+)+5D2(Eu3+)] and [4F9/2(Dy3+)+7F0(Eu3+)→6H13/2(Dy3+)+5D0(Eu3+)]. The color coordinates of the Dy3+/Eu3+ co‐doped glasses under various excitations fall within the white light emission spectrum, indicating their potential application in warm white LEDs.

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“… 51 Also, the average photoluminescent lifetime was calculated as . 52 The average lifetimes also increased from 2208 ns for the colloidal QDs to 2450 ns for the LSC.…”

“…The lifetimes of the slowest decay component τ 2 were 2506 and 2811 ns for the colloidal QDs and LSC, respectively, indicating longer-lived excited states in the LSC due to a possible reduced QD interaction, preventing the nonradiative recombination . Also, the average photoluminescent lifetime was calculated as τ avg = false( A 1 τ 1 2 + A 2 τ 2 2 false) / false( A 1 τ 1 + A 2 τ 2 false) . The average lifetimes also increased from 2208 ns for the colloidal QDs to 2450 ns for the LSC.…”