Superior thermally-stable narrow-band green emitter from Mn²⁺-doped zero thermal expansion (ZTE) material

Thermal quenching is still a pivotal challenge for phosphor materials in white light emitting diodes lighting applications. Herein, we propose an effective strategy to design a near zero-thermal-quenching green emission in zero-thermal-expanding Zn₄B₆O₁₃ host based on unique 3D isotropic cage structure. The integrated emission intensity of Zn₄B₆O₁₃:Mn²⁺ could maintain 103% of initial intensity at 150 °C and 98% at 250 °C under blue light excitation. During the low-frequency vibrations, the unchanged bonds and angles induce the zero thermal expansion, and the unaffected lattice and coordination environment contribute the nearly unchanged emission intensity during the heating process. In addition, an efficient self-reduction of activators in the studied system is ascribed to vacancy and interstitial oxygen defects act as donors to provide electrons. This work initiates a novel strategy to construct thermally-stable and self-reductive phosphors for multiple optical applications.