Tb-based phosphor BaTb4Si3O13:Eu3+ with high energy transfer efficiency for white LEDs

The conventional random co-doping of Tb 3+ and Eu 3+ leads to spatial separation that severely limits energy transfer efficiency between these ions, which is critical for minimizing non-radiative losses in white LEDs. To address the limitation, we designed BaTb 4- x Si 3 O 13 : x Eu 3+ , breaking through the bottleneck by occupying Tb 3+ sites with Eu 3+ . Rietveld refinement and ionic radius analysis confirmed site occupancy selectivity, enabling 71.59 % Tb 3+ →Eu 3+ energy transfer efficiency, which is higher than conventional random doping systems. Under 380 nm excitation, the phosphor yielded red emission with CIE coordinates of (0.6153,0.3838) and 86.64 % color purity, and exhibited exceptional thermal stability with 70 % intensity retention at 473 K. Fabricated wLEDs using a NUV chip with commercial blue phosphor, green phosphor, and the developed phosphor produced warm white light with a correlated color temperature of 4519 K and CIE coordinates of (0.3478, 0.3868), achieving a high color rendering index of 87.4. These results demonstrate BaTb 4 Si 3 O 13 :Eu 3+ as a highly promising red phosphor candidate for solid-state lighting applications.