YAG:Tb@YAG:Pr Single Crystalline Dual‐Layer Phosphor. An Alternative Approach to Multimodal Wide Range Luminescence Thermometry

Abstract The SC‐YAG:Tb@YAG:Pr‐SCF composite epitaxial structure consisting of a 1 mm thick single crystal substrate of YAG:Tb garnet and a thin (9 µm) single crystalline film of YAG:Pr garnet is fabricated, and its luminescent properties are examined toward luminescence thermometry. The possibility to efficiently excite, individually or simultaneously, the Tb³⁺ and Pr³⁺ dopants by their intense allowed 4f→5d transitions is executed to reach relative thermal sensitivity higher than 1% K⁻¹ over the range of temperatures as wide as 100–625 K and above 0.5% K⁻¹ over 13–650 K. The obtained results demonstrate that using intra‐ and inter‐configurational emission transitions of Pr³⁺ and other lanthanides makes it possible to design wide‐range luminescence thermometers with high sensitivity spanning the entire operating limits.