Antithermal Quenching in Sm³⁺ Doped Double Perovskite Phosphors

In modern high-power lighting systems, significant thermal effects can lead to the performance degradation of light-emitting diodes (LEDs), which places higher requirements on the thermal stability of luminescent materials for color conversion. Currently, the thermal stability of red phosphors remains a critical bottleneck for high-power white light-emitting diodes (wLEDs). To address this, we report a red phosphor, Ca₂GdSbO₆:Sm³⁺ (CGSO:Sm³⁺), exhibiting significant antithermal quenching. This remarkable property is attributed to a synergistic mechanism involving the rigid double-perovskite host structure and efficient thermally driven energy transfer from deep-level defects to the Sm³⁺ emitting centers. As a result, the phosphor exhibits outstanding thermal stability, with the emission intensity at 250 °C reaching 160% of its initial value at room temperature. A prototype wLED fabricated by using CGSO:Sm³⁺ as the red component achieves a high color rendering index (Ra = 90) and excellent color stability. These findings establish CGSO:Sm³⁺ as a promising candidate for high-performance lighting and offer a new design strategy for developing luminescent materials with high thermal stability.