Energy transfer-based color tunability, thermal quenching, and quantum yield of Sm3+/Eu3+ codoped lithium zinc borophosphate glasses

Abstract

Lithium zinc borophosphate (LZBP) glasses, imbedded with Sm3+, Eu3+, & Sm3+/Eu3+ ions in solely and combinedly were synthesized using melt-quenching technique, and their energy-transfer-dependent photoluminescence (PL)-related characteristics were explored. LZBP: 0.5 % Sm3+ and LZBP: 0.5 % Eu3+ glasses exhibited intense orange and red emissions under 404 and 394 nm excitation wavelengths, respectively. When the Sm3+/Eu3+ codoped glass systems were excited with Sm3+ excitation (404 nm), has lead to a noticeable drop in the emission intensity of Sm3+ peaks at 562 nm (4G5/2 → 6H5/2; yellow), 602 nm (4G5/2 → 6H7/2, orange), and 645 nm (4G5/2 → 6H9/2, red) whereas the emission intensity of Eu3+ peaks at 591 nm (5D0→7F1; orange) and 617 nm (5D0→7F2; red) has enhanced. At the same time, the decay lifetime of singly doped Sm3+ decreased from 1.54 to 0.91 ms, with codoping different concentrations of Eu3+ ions. The decrease in both PL intensity and lifetimes of Sm3+ in the presence of Eu3+ suggests an efficient energy transfer (ET) from Sm3+→Eu3+, which is facilitated by dipole-dipole interaction. The ET from Sm3+→Eu3+ achieved through the channels, Sm3+:4G5/2 + Eu3+:7F1 → Sm3+:6H7/2 + Eu3+:5D0 and Sm3+:4G5/2 + Eu3+:7F2 → Sm3+:6H5/2 + Eu3+:5D1. Furthermore, ET from Sm3+ to Eu3+ is supported by the spectral overlay between Sm3+ emission and Eu3+ absorption, ET parameters (η(Sm3+⟶Eu3+) = 40.91 % and P(Sm3+⟶Eu3+) = 1098.9 S-1). The shift in color coordinated from orange to red, with an increase in Eu3+ doping content in the codoped glasses at 404 nm excitation demonstrates the promising application of the Sm3+/Eu3+ codoped glass system in orange-red light-emitting diodes. LZBP: 0.5 Sm3+/1.0 Eu3+ codoped glass exhibited good thermal stability (Ea = 0.19 eV), depending on temperature-dependent PL properties. The quantum yield (η) for the LZBP glass containing 0.5 Sm3+/1.0 Eu3+ codoped ions is evaluated to be 44.6 %.