Fluorescent probe effect of super-sensitive transition Dy³⁺ ions in the negative thermal expansion materials Sc₂W₃O₁₂

Negative thermal expansion (NTE) materials have attracted significant attention for their distinctive thermal expansion properties and potential applications in various fields such as micro-electronic packaging, aerospace engineering, optics, and sensors. Despite significant advancements, the field continues to face numerous challenges, including scarcities in material types, unclear mechanisms underlying thermal shrinkage, response temperature far from room temperature, as well as limited potential for industrialization. In our work, we report a type of Sc2W3O12:Dy3+ luminescent material whereby the doped super-sensitizing rare earth ion Dy3+ can form luminescent centers within a specific crystal field environment, thereby extending the optical properties of NTE materials. With the temperature increasing, the emission of WO42- undergoes a red shift, and the yellow-to-blue (Y/B) ratio resulting from Dy3+ transitions increase, effectively illustrate the W-O bond spacing decreases. The effect of lattice shrinkage with increasing temperature is proved by the optical performance of luminescent ions in the NTE materials, gives rare earth ions the role of fluorescent probes in the process of negative thermal expansion. This also provides a novel strategy for the dynamic monitoring of lattice environments that vary with temperature.