Sm³⁺-Mn⁴⁺ activated Sr₂GdTaO₆ red phosphor for plant growth lighting and optical temperature sensing

Optical temperature sensing and plant growth lighting multifunctional applications can be realized by red luminescent materials. In this paper, novel Sm³⁺ and Sm³⁺-Mn⁴⁺ activated Sr₂GdTaO₆ (SGTO) red phosphors for plant growth and optical temperature sensing were comprehensively analyzed. The phase, luminescence property and thermal stability of the material were tested. For PL performance, SGTO:0.075Sm³⁺ exhibits the maximum emission intensity in the range (560–670 nm). The emission range of SGTO:0.075Sm³⁺ after introducing Mn⁴⁺ is mainly dark red light emission in the range from 630 to 750 nm, and the optimum doping concentration of Mn⁴⁺ is determined to be 0.3 %. The emission band of SGTO:0.075Sm³⁺ and SGTO:0.075Sm³⁺, 0.003Mn⁴⁺ matches the absorption band of the plants. For optical temperature sensing properties, the relative sensitivity (S_r) and absolute sensitivity (S_a) of SGTO:0.075Sm³⁺, 0.003Mn⁴⁺ are 2.94 K⁻¹ (298 K) and 0.635 K⁻¹ (573 K), respectively. The results indicate that Sm³⁺-Mn⁴⁺ activated SGTO red phosphor is a luminescent material with potential application in plant growth and optical temperature sensing field.