Luminescent Properties and Luminous Thermal Stability of Adjusting Colorful 100 mol% Activator Tb2(1−x)Eu2x(MoO4)3 Phosphors

ABSTRACT Rare‐earth‐doped phosphors have garnered significant attention for their pivotal role in optoelectronic devices, yet the development of high‐concentration activator systems with tunable luminescence and robust thermal stability remains a challenge. By adjusting the contents of Tb 3+ and Eu 3+ , a series of 100 mol% activator Tb 2(1− x ) Eu 2 x Mo 3 O 12 phosphors (0 ≤ x ≤ 1) were prepared through a solid‐state reaction method. All Tb 2(1− x ) Eu 2 x Mo 3 O 12 phosphors crystallized in the orthorhombic phase, and the energy band gap ( E g ) decreased from 3.77 eV ( x = 0) to 3.39 eV ( x = 1) due to lattice expansion induced by Eu 3+ substitution. Tunable emission from green to red was achieved through efficient energy transfer (ET) from Tb 3+ to Eu 3+ , with even 0.5 mol% Eu 3+ doping significantly altering photoluminescence (PL) properties. Notably, Tb 2 Mo 3 O 12 and Eu 2 Mo 3 O 12 exhibited contrasting thermal behaviors despite identical crystal structures, attributed to differences in electronic configurations. The Tb 2(1− x ) Eu 2 x Mo 3 O 12 phosphor demonstrated stable thermal activation energy ( E a ) across temperatures, highlighting its potential for high‐temperature applications. Fabricated LEDs with 380‐ or 397‐nm chips emitted adjustable green, yellow, and red light, confirming the viability of prepared materials for lighting technologies. This study provides insights into designing high‐concentration activator phosphors with tunable emissions and enhanced thermal stability, advancing their applicability in next‐generation optoelectronic devices.