High thermal stability Gd5-x-ySi2BO13:xTb3+, yEu3+ phosphors achieve color tunable emission through Tb3+-Eu3+ energy transfer

Abstract

A series of Gd_5-xSi₂BO₁₃: xRE³⁺ (Tb³⁺, Eu³⁺, Tb³⁺/Eu³⁺) phosphors were successfully synthesized using high-temperature solid-state method. Color tunable single-phase phosphors were obtained through energy transfer between Tb³⁺ and Eu³⁺. The phase structure, luminescence characteristics, and energy transfer mechanism of the obtained fluorescent powder were systematically studied. The energy transfer (ET) process from Tb³⁺ to Eu³⁺ was determined to occur through exchange interactions. By changing the Tb/Eu doping concentration ratio, multi-color luminescence can be achieved under 377 nm light excitation, with emission colors adjusted from green and orange to red. The comprehensive emission intensity of Gd_4.42Si₂BO₁₃:0.55Tb³⁺, 0.03Eu³⁺ at 150 °C was 87.73 % of that at room temperature, the activation energy is 0.20 eV, indicating good thermal stability. Finally, the potential applications of the samples in the fields of lighting and anti-counterfeiting were explored. Encapsulate the synthesized Gd_4.42Si₂BO₁₃:0.55Tb³⁺, 0.03Eu³⁺ phosphors in commercial w-LEDs for actual performance testing. Ra is 90.6, CCT is 3441 K, and the light source performance is good. Using screen printing technology, Gd_4.42Si₂BO₁₃:0.55Tb³⁺, 0.03Eu³⁺ phosphors were prepared into anti-counterfeiting ink, and optical anti-counterfeiting patterns were made on glass. The pattern will not be visible when placed in a white environment but will emit yellow and red fluorescence under 365 nm and 395 nm UV excitation, respectively. The results indicate that Gd_5-x-ySi₂BO₁₃:xTb³⁺, yEu³⁺ is a multi-color tunable single-phase fluorescent powder with good luminescence performance and thermal stability, which can be applied in the field of ultraviolet excited w-LED and has potential application value in the field of optical anti-counterfeiting.