Jia Mochen, Sun Zhen, Zhang Mingxuan, Xu Hanyu, Fu Zuoling
Coherent Light and Atomic and Molecular Spectroscopy Laboratory, Key Laboratory of Physics and Technology for Advanced Batteries, College of Physics, Jilin University, Changchun 130012, China.
Nanoscale. 2020 Oct 22;12(40):20776-20785. doi: 10.1039/d0nr05035k.
Luminescence intensity ratio (LIR) nanothermometers are ideally suited for noninvasive temperature detection of microelectronic devices and living cells, and the painstaking pursuit of new nanothermometers with higher absolute temperature sensitivity (Sa) or relative temperature sensitivity (Sr) has dominated recent research. However, whether higher Sa and Sr values can intrinsically improve the performance of LIR nanothermometers and what factors essentially determine their accuracy have rarely been considered; these considerations are instructive for their design and application while reducing time and costs. Here, we clarify that the accuracy of lanthanide-based LIR nanothermometers is essentially determined by Sr and the relative error of the luminescence intensity (σI/I) but not Sa based on lanthanide-doped NaYF4, YPO4, YVO4, CaF2, YF3, Y2O3, BaTiO3, LaAlO3 and Y3Al5O12 temperature sensors, meaning that our previous pursuit of higher Sa does not contribute to the accuracy of lanthanide-based LIR nanothermometers. Further research reveals that σI/I is primarily influenced by energy level splitting, which can deteriorate the temperature uncertainty. For actual temperature detection of biological tissues, in addition to the above intrinsic factors, we shed light on the effects of probe self-heating, excitation power density, emission intensity and penetration depth on temperature readouts via a polyethyleneimine-modified NaYF4:Er3+/Yb3+@NaYF4-PEI aqueous solution, implying that we will continue to optimize nanothermometers and calibrate readouts according to the local environment. This work unifies the metrics of lanthanide-based LIR nanothermometers, corrects the previous misunderstanding of Sa to mitigate invalid work, and provides careful guidance for their development.
发光强度比（LIR）纳米温度计非常适合用于微电子设备和活细胞的非侵入式温度检测，近期的研究主要致力于苦心探寻具有更高绝对温度灵敏度（Sa）或相对温度灵敏度（Sr）的新型纳米温度计。然而，更高的Sa和Sr值是否能从本质上提升LIR纳米温度计的性能，以及哪些因素从根本上决定了它们的准确性，这些问题很少被考虑；而这些考量对于在减少时间和成本的同时进行其设计和应用具有指导意义。在此，我们基于镧系掺杂的NaYF4、YPO4、YVO4、CaF2、YF3、Y2O3、BaTiO3、LaAlO3和Y3Al5O12温度传感器阐明，基于镧系的LIR纳米温度计的准确性本质上由Sr和发光强度的相对误差（σI/I）决定，而非Sa，这意味着我们之前对更高Sa的追求对基于镧系的LIR纳米温度计的准确性并无助益。进一步的研究表明，σI/I主要受能级分裂的影响，这会使温度不确定性恶化。对于生物组织的实际温度检测，除了上述内在因素外，我们通过聚乙烯亚胺修饰的NaYF4:Er3+/Yb3+@NaYF4-PEI水溶液揭示了探针自热、激发功率密度、发射强度和穿透深度对温度读数的影响，这意味着我们将继续根据局部环境优化纳米温度计并校准读数。这项工作统一了基于镧系的LIR纳米温度计的指标，纠正了之前对Sa的误解以减少无效工作，并为其发展提供了审慎的指导。
