High thermal stability of green-emitting phosphor NaBaB9O15: Tb3+ via energy compensation

The quenching of luminescence intensity of phosphors with increasing temperature is one of the factors that limit the practical application of the phosphor-converted white light-emitting diodes (pc-WLEDs). Herein, we report a green-emitting NaBaB9O15: xTb3+ phosphor that exhibits outstanding thermal stability at high temperatures. The luminescence intensity of NaBaB9O15: xTb3+ phosphors exhibit no thermal quenching up to 250 °C under 370 nm excitation. The zero-thermal-quenching effect can be ascribed to the energy compensation of defect levels. To reveal the zero-thermal-quenching mechanism, we have investigated the crystal structure, electronic band structure of the NBBO, and thermoluminescence. Thermally activated defect levels capture electrons and transfer energy to the Tb3+ ions to compensate for the emission loss at high temperatures. The results manifest that the as-prepared green-emitting NaBaB9O15:Tb3+ phosphors with excellent thermal stability are promising candidates for WLED applications. These finds may offer a guide for the exploration of the Tb3+ activated phosphors with excellent thermal stability.