Anti-thermal-quenching red-emitting phosphors based on lanthanide doped negative-thermal-expansion (NTE) hosts

Thermal quenching (TQ) is still a critical challenge for phosphor materials (especially for red phosphors) in white light emitting diodes lighting applications. Herein, we put forward an effective method to design anti-TQ red emission of Eu3+ in the unique negative-thermal-expansion (NTE) orthorhombic Sc2(Mo,W)3O12 hosts. Surprisingly, the emission intensity of Sc2Mo3O12:Eu3+ (SMO:Eu3+) is enhanced to 150% of initial intensity at 150 °C and 123% of initial intensity at 200 °C under blue light excitation. Similarly, the Sc2W3O12:Eu3+ (SWO:Eu3+) also could exhibit 123% of initial intensity at 150 °C and 106% at 200 °C. According to the variable-temperature X-ray diffraction and photoluminescence results, the unique anti-TQ phenomenon should be ascribed to the improved structural rigidity induced by the contraction of cell volumes and energy transfer from traps. By employing a 380 nm UV chip, the as-fabricated white LEDs using Sc2Mo3O12:Eu3+ phosphor presents a warm white light with CIE color coordinates (0.3112, 0.3198), low corresponding color temperature (CCT = 5045 K), and high color rendering index (CRI = 90.6). This work initiates a novel strategy to construct anti-TQ red-emitting phosphors for multiple practical optical applications.