Emission color tuning and dual-mode luminescence thermometry design in Dy³⁺/Eu³⁺ co-doped SrMoO₄ phosphors

Abstract

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 SrMoO4 phosphors 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−1 at 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.

Thermal imaging study of Sm2+ doped SrB4O7 based on time-resolved technology

“…The relative sensitivity is 7.64% K −1 at 500 K while it reaches 9.67% K −1 as the temperature increases to 533 K. This is an excellent sensitivity value for temperature sensing materials, compared with recently reported results (Table 1). 22–27 Furthermore, using the total intensity of the sample rather than a specific wavelength range greatly increases the signal intensity because no signal is likely lost due to wavelength selection. The high sensitivity and excellent signal quality of this method make it promising in thermal sensing applications.…”

Strategic Investigation of Dual-Mode Light Emission from Tm3+/Ho3+/Yb3+-Activated NaLa(MoO4)2 Phosphors for Color Tunability and Optical Temperature Sensing Applications

“…The commonly used LIR technique involves the intensity ratio of the two thermally coupled energy levels (TCLs) of Ln 3+ ion with an energy gap between 200 and 2000 cm –1 . Among various Ln 3+ ions, Pr 3+ , Dy 3+ , Er 3+ , Ho 3+ , Gd 3+ , Nd 3+ , and Tm 3+ have TCLs in their 4f electronic configuration. − The LIR technique involving Ln 3+ ions with TCLs is governed by the Boltzmann distribution law, and therefore, the relative temperature sensitivity is proportional to the energy gap of the two TCLs. However, the thermal coupling of the two energy levels has an upper limit on the energy separation of about 2000 cm –1 , and this imposes restriction on the maximum sensitivity that can be reached from a single Ln 3+ ion.…”