Ayachi Fadwa, Saidi Kamel, Dammak Mohamed, Mediavilla Irene, Jiménez Juan
Département de Physique, Laboratoire de Physique Appliquée, Faculté des Sciences de Sfax, Université de Sfax BP 1171 Sfax Tunisia
Department of Condensed Matter Physics, GdS Optronlab, LUCIA Building, University of Valladolid Paseo de Belén 19 47011 Valladolid Spain.
RSC Adv. 2025 Jan 8;15(1):655-664. doi: 10.1039/d4ra08590f. eCollection 2025 Jan 2.
Luminescent materials doped with rare-earth (RE) ions have emerged as powerful tools in thermometry, offering high sensitivity and accuracy. However, challenges remain, particularly in maintaining efficient luminescence at elevated temperatures. This study investigates the thermometric properties of BiVO: Yb/Er (BVO: Er/Yb) nanophosphors synthesized the sol-gel method. Structural, morphological, and optical analyses confirm the high purity and monoclinic crystal structure of the materials. Dual-mode luminescence under UV and near-infrared (NIR) excitation is explored, revealing complex thermal dynamics. The distinct performances of these luminescent thermometers, in terms of thermal sensitivity and temperature uncertainty, were evaluated in the non-saturation regime in both down-shifting (DS) and up-conversion (UC) processes. Utilizing fluorescence intensity ratio (LIR) measurements, we quantified absolute and relative sensitivities, as well as temperature uncertainties, over a temperature range of 300-450 K. Temperature sensing was based on the LIR of green emission bands arising from the thermally coupled H → I and S → I transitions of Er. The maximum absolute sensitivity ( ) reached 60 × 10 K at 388 K under 975 nm excitation (UC) and 56 × 10 K at 400 K under 325 nm excitation (DS). Notably, for both excitation modes, the relative sensitivity ( ) decreased consistently with increasing temperature, peaking at 0.908% K and 0.87% K at 300 K, and gradually declining to 0.4% K and 0.39% K at 450 K for the DS and UC processes, respectively. Temperature resolution (δ) also varied with temperature, increasing from 0.55 K to 1.23 K as the temperature rose from 300 to 450 K under 325 nm excitation. A comparable trend was observed for δ under 975 nm excitation. These findings underscore the potential of BVO: Er/Yb nanophosphors as versatile and effective luminescent thermometers for a broad range of applications.
掺杂稀土（RE）离子的发光材料已成为温度测量领域的强大工具，具有高灵敏度和准确性。然而，挑战依然存在，尤其是在高温下保持高效发光方面。本研究调查了通过溶胶 - 凝胶法合成的BiVO: Yb/Er（BVO: Er/Yb）纳米磷光体的测温特性。结构、形态和光学分析证实了材料的高纯度和单斜晶体结构。探索了紫外和近红外（NIR）激发下的双模发光，揭示了复杂的热动力学。在向下转换（DS）和上转换（UC）过程的非饱和区域中，评估了这些发光温度计在热灵敏度和温度不确定性方面的不同性能。利用荧光强度比（LIR）测量，我们在300 - 450 K的温度范围内量化了绝对和相对灵敏度以及温度不确定性。温度传感基于Er的热耦合H→I和S→I跃迁产生的绿色发射带的LIR。在975 nm激发（UC）下，388 K时最大绝对灵敏度（ ）达到60×10 K，在325 nm激发（DS）下，400 K时达到56×10 K。值得注意的是，对于两种激发模式，相对灵敏度（ ）均随温度升高而持续下降，在300 K时，DS和UC过程分别达到峰值0.908% K和0.87% K，在450 K时逐渐降至0.4% K和0.39% K。温度分辨率（δ）也随温度变化，在325 nm激发下，随着温度从300 K升至450 K，δ从0.55 K增加到1.23 K。在975 nm激发下观察到δ有类似趋势。这些发现强调了BVO: Er/Yb纳米磷光体作为适用于广泛应用的通用且有效发光温度计的潜力。
