Emission color tuning and dual-mode luminescence thermometry design in Dy³⁺/Eu³⁺co-doped SrMoO₄phosphors

The challenge of building a highly reliable contactless temperature probe with high sensitivity, good temperature-induced color discriminability, and economical synthesis has prompted the research community to work in the field of rare-earth-based luminescence thermometry. Moreover, the fast-growing market for optoelectronic devices has increased the demand for tunable color-emitting phosphors. In this study, Dy³⁺/Eu³⁺co-doped SrMoO₄phosphors were developed as tunable color-emitting source and dual-mode luminescence thermometer. A facile and cost-effective auto-combustion method was used to synthesize the phosphors. Our work demonstrates a viable scheme for tailoring the emission of single-phase phosphors by precisely controlling the dopant concentrations and by modulating excitation wavelength. The overall emission is tuned from greenish-yellow to white and greenish-yellow to reddish-orange. A detailed energy transfer process from the host to the Ln³⁺ions and between the Ln³⁺ions is discussed. Further, anti-thermal quenching in the emission of Dy³⁺ion is observed when excited with 297 nm. The dual-mode luminescence thermometry has been studied by analyzing the fluorescence intensity ratio of Dy³⁺and Eu³⁺ions upon excitation at 297 nm. The maximum relative sensitivity value for 4% Eu³⁺co-doped SrMoO₄:4%Dy³⁺phosphor is 1.46% K^-1at 300 K. Furthermore, the configurational coordinate diagram is presented to elucidate the nature of temperature-dependent emission. Therefore, our research opens up new avenues for the development of color-tunable luminescent materials for various optoelectronic and temperature-sensing applications.