Highly thermally stable CaLaMgSbO6: Sm3+ double perovskite phosphors for optical thermometer and plant growth

A series of CaLaMgSbO 6 : Sm 3+ orange-red phosphors were synthesized using a high-temperature solid-state method. These phosphors' phase, luminescence properties, and thermal stability were thoroughly investigated. Under 405 nm excitation, the CaLaMgSbO 6 : Sm 3+ phosphor exhibit a broadband orange-red emission with the maximum emission peak positioned at 598 nm. The optimal CaLaMgSbO 6 : 0.025Sm 3+ phosphor features CIE chromaticity coordinates of (0.5902, 0.4085) with an orange-red hue. Impressively, the emission intensity at 423 K remains at 78.7 % of its room temperature intensity, which shows its outstanding thermal stability. The emission spectra of light-emitting diodes (LEDs) fabricated with CaLaMgSbO 6 : 0.025Sm 3+ phosphor possess a large overlap with the absorption band of phytochromes. Meanwhile, the temperature-sensing properties of CaLaMgSbO 6 : Sm 3+ phosphors were studied across various wavelength bands using the fluorescence intensity ratio (FIR) technique. The relative sensitivity of FIR (I 598 /I 563 ) was found to be highest at 298 K, measuring 0.15 % K −1 . The above research results suggest that CaLaMgSbO 6 : Sm 3+ phosphors have potential applications in plant growth and optical temperature sensing.