Structural confinement helps achieve more accurate energy transfer: studies on garnet structural NYGlG:Tb,Eu phosphors

In the quest to enhance the performance of white light-emitting diodes (WLEDs), the development of efficient red phosphors is essential. To address this issue, a series of co-doped garnet-type phosphors, NaY 2 Ga 2 InGe 2 O 12 :Tb 3+ ,Eu 3+ (NYGIG:Tb 3+ ,Eu 3+ ), were synthesized, utilizing structural confinement to achieve more precise energy transfer and improve luminescence performance. Comprehensive characterization techniques, including powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and elemental mapping, confirmed the structural and compositional features of the phosphors. Na + ions occupy one-third of the eight-coordinated sites in NYGIG, separating Tb 3+ and Eu 3+ ions, which improves the precision of energy transfer. Statistical results demonstrate that Na + increases the formation probability of Tb 3+ -Eu 3+ pairs to 7%, effectively preventing the formation of long Tb 3+ -Tb 3+ and Eu 3+ -Eu 3+ chains while the probability of forming a Tb 3+ -Eu 3+ pair is merely 3.12% in traditional garnets. When the Tb 3+ doping concentration is 50%, the energy transfer efficiency reaches 95% at an optimal Eu 3+ doping concentration of 7%. Moreover, the NYGIG:0.5Tb 3+ ,0.07Eu 3+ phosphor achieves a quantum yield of 70.4% and maintains strong luminescence intensity at elevated temperatures, retaining over 85% of its room temperature luminescence intensity at 425 K. The electroluminescence (EL) spectrum of the assembled WLED, powered using a 365 nm near-UV chip, shows balanced white light output with a high color rendering index (CRI ∼ 87) and CIE coordinates of (0.402, 0.380). These findings underscore the significant potential of NYGIG:Tb 3+ ,Eu 3+ phosphors for advancing highly efficient WLED technologies. Structural confinement in sodium-rich garnets enables more accurate Tb 3+ -Eu 3+ energy transfer, enhancing luminescence performance. The Na + -doped system shows an energy transfer efficiency of 95% and stable emission for WLED applications.