Warm white light phosphors Sc2W3O12: Dy3+, Eu3+ with ultrahigh thermal stability and tunable luminescence

• The actual band gap values calculated by diffuse reflectance spectroscopy combined with the theoretical band gap values calculated by density-functional theory (DFT) illustrate the relevant optical properties of Sc 2 W 3 O 12 : Dy 3+ , Eu 3+ phosphors • The reason for the high energy transfer efficiency of 75 % for Dy 3+ , Eu 3+ was analyzed by combining the energy transfer mechanism and J-O theory calculations. • Sc 2 W 3 O 12 : 0.03Dy 3+ , 0.05Eu 3+ phosphors were prepared with thermal stability up to 90.38 %. XRD tests on Sc 2 W 3 O 12 : 0.03Dy 3+ , 0.05Eu 3+ phosphors in the temperature range of 303 K-483 k show that the ultra-high thermal stability is related to the stable structural stiffness and negative thermal expansion of the phosphors. • By adjusting the concentration ratio of Dy 3+ and Eu 3+ in the Sc 2 W 3 O 12 : Dy 3+ , Eu 3+ phosphor, the transformation of the phosphor from cool white light to warm white light was realized. • Luminescent devices with Sc 2 W 3 O 12 : 0.03Dy 3+ and Sc 2 W 3 O 12 : 0.03Dy 3+ , 0.05Eu 3+ phosphors were prepared, confirming the potential application of Sc 2 W 3 O 12 : Dy 3+ , Eu 3+ phosphors in WLEDS. Phosphors for lighting applications often face challenges such as limited thermal stability, restricted tunability of emission colors, and moderate quantum efficiency. In this study, a series of Sc 2 W 3 O 12 : x Dy 3+ , y Eu 3+ phosphors were synthesized via a high-temperature solid-state method to address these issues. Under 350 nm excitation, Sc 2 W 3 O 12 : x Dy 3+ phosphor exhibits blue (485 nm) and yellow emission peaks (577 nm), and the optimal doping concentration of Dy 3+ is 3 mol%. In Sc 2 W 3 O 12 : 0.03Dy 3+ , y Eu 3+ phosphor, energy transfer is revealed through spectral overlap and fluorescence decay curve analysis of Dy 3+ and Eu 3+ . The energy transfer efficiency is as high as 75 %, and the reason is explained through a combination of energy transfer mechanism and J-O theoretical calculation. By adjusting the range of y in Sc 2 W 3 O 12 : 0.03Dy 3+ , y Eu 3+ , the correlated color temperature can be adjusted within the range of 4450 K to 3945 K, thereby achieving tunable luminescence from neutral white light to warm white light. The thermal stability of the synthesized warm white phosphor Sc 2 W 3 O 12 : 0.03Dy 3+ , 0.05Eu 3+ is 90.38 % (423 K). The fluorescence intensity ratio of Eu 3+ and Dy 3+ at 303 K − 483 K was calculated, and its temperature sensing performance was analyzed. At 303 K, the thermal sensing factors are S amax = 0.97 % K −1 and S rmax = 0.0962 % K −1 , and the actual quantum efficiency is IQE = 50.67 %. Finally, a WLED device was prepared using Sc 2 W 3 O 12 : 0.03Dy 3+ , 0.05Eu 3+ phosphors. The device emits warm white light with a correlated color temperature of 3686 K. In summary, the prepared Sc 2 W 3 O 12 : Dy 3+ , Eu 3+ phosphor successfully solved the challenges of limited thermal stability, tunable luminescence color and moderate quantum efficiency, and it has potential value in white light-emitting diodes (WLEDs) and optical thermometers.