Structural and Optical interpretations on KNN-based Transparent Ceramic Application in Optical Thermometry Category: Oral presentation

Author : Quan Zhang, Shuangying Lei

Abstract :Luminescence thermometry has emerged as a powerful tool for non-contact temperature sensing, driven by significant advancements aimed at enhancing thermal sensitivity. In this study, we present Ta⁵⁺-substituted K₀.₅Na₀.₅NbO₃:0.003Er³⁺ transparent ferroelectric ceramics as a highly promising material for advanced luminescence-based thermometric applications. The temperature-dependent fluorescence intensity ratio (FIR) between the thermally coupled ²H₁₁/₂ and ⁴S₃/₂ levels of Er³⁺ ions was utilized to achieve effective temperature detection across a broad 273–543 K range. By optimizing the Ta⁵⁺ concentration, a maximum absolute sensitivity of 0.0058 K⁻¹ and a relative sensitivity of 0.0158 K⁻¹ were achieved for the specific composition K₀.₅Na₀.₅NbO₃:0.65Ta⁵⁺/0.003Er³⁺. Notably, increasing Ta⁵⁺ substitution led to a structural evolution from orthorhombic to tetragonal, and finally to a cubic phase, with the highest thermometric sensitivity observed in the cubic phase region. This phase transition directly influences the luminescence properties of the ceramics, with remarkable enhancements in sensitivity and clear changes in infrared luminescence around the transition temperature. These findings not only highlight the potential of Ta⁵⁺-modified K₀.₅Na₀.₅NbO₃：Er³⁺ ceramics as a highly sensitive luminescent thermometer but also introduce them as a novel tool for simultaneous temperature sensing and phase transition monitoring. Consequently, this material represents a valuable candidate for applications requiring precise thermal sensing and structural diagnostics, particularly in fields where high sensitivity and the ability to detect phase changes are essential.

Keywords :Luminescence thermometry, FIR technique, Ta⁵⁺-doped K₀.₅Na₀.₅NbO₃, phase transition, thermal sensitivity

Conference Name :International Conference on Materials Physics and Energy Materials (ICMPEM-24)

Conference Place Copenhagen, Denmark

Conference Date 15th Nov 2024