Designing bifunctional platforms for LED devices and luminescence lifetime thermometers: a case of non-rare-earth Mn4+ doped tantalate phosphors

Non-rare-earth Mn4+ doped tantalate (Sr2GdTaO6) phosphors exhibiting deep-red emission were synthesized. Afterward, the phase structure, morphology, and optical properties (e.g., emission spectra, concentration quenching, decay curves, thermal stability, quantum yields, etc.) were systematically investigated. Under the optimal conditions, the Sr2GdTaO6:0.005Mn4+ phosphor showed an excellent color purity of 96.41% while the chromaticity coordinates were (0.721, 0.279). Besides, the optimal sample exhibited good thermal stability, and, hence, it can be packaged into light-emitting diode (LED) devices. Red-emitting LED devices could show strong far-red emission and could be suggested for plant cultivation lighting. On the other hand, white-emitting LED devices could find use in indoor illumination. Moreover, with the aid of temperature-dependent lifetime (TDL), a good relative sensing sensitivity (1.73% K-1 at 453 K) of the luminescent thermometer was established. Herein, all the above findings suggested that Sr2GdTaO6:Mn4+ phosphors are a potential candidate for bifunctional platforms of solid-state lighting and luminescence lifetime thermometers.