温度传感的稳态荧光方法研究

Fluorescent temperature sensing has attracted numerous attention for biological applications. Since some sensing techniques have been developed, more other mechanisms are proposed here demonstrating temperature-dependent ratio of fluorescence. The first one originates from phonon-assisted energy transfer process, where the phonon density depends on temperature. The second type occurs in an excitation/absorption process, while electrons distribution in the initial state follows the Boltzmann's principle. The third mechanism describes a resultant change of relative intensity as a combined effect of broadening and shifting of an emission band. And the last one uses integral intensity of parts of a broadband for the ratiometric sensing.. In addition, shift of emission band barycentre is proposed to be a temperature sensing signal instead of the band peak shift. Accordingly the signal-to-noise ratio can be increased and slight shift can be distinguished even if beyond the spectrometer's definition limit. When other spectrum characteristics e.g. the Full-Width-at-Half-Magnitude are also observed under varying temperature, a steady-state fluorescence has been fully characterised for temperature sensing.. Fine precision and high flexibility can be achieved using the proposed methods. The proposal also means a re-defination of the concept of the fluorescent temperature sensing. The experimental results are capable to contribute enormously to the condensed-matter physics by deeply understanding the relationship between material structure and its performance. Advanced active materials might be developed with any achieved sensing functions behind.

荧光测温技术适合中低温区应用，在生物、化学领域正蓬勃发展。本项目提出处理荧光温度传感信号的多个方法：1，区别于传统荧光强度比技术的四类比例法，包括，当发光离子间存在声子协助能量传递时，温度影响声子密度从而改变不同离子荧光的强度比；激发或吸收光谱的谱峰强度比对应于低能态上的电子分布，符合热平衡分布规律；宽带发光谱带上不同波长处的强度比能反映温敏谱型变化；发光谱带分段的积分强度之比可能随温度变化；2，针对宽带光谱寻峰精度低的问题，以谱带重心频移代替谱带峰值位置频移作为传感信号，能够提高信噪比、分辨出小于光谱仪极限分辨率的频移。结合谱峰展宽等其它传感方式，项目较全面地考虑了稳态荧光的各项光谱特征用于温度传感的可行性。. 项目方法能显著提高荧光测温精度，为具体应用提供更大灵活度，拓展荧光传感的理论内涵；传感方程可以用于检验固体物理、化学理论对材料性能的预期，并指导开发其它传感应用及敏感材料。

温度的荧光式传感方法是近十年兴起的一类测温技术，具有光测技术的典型特性并还有空间分辨率高、可无线传输信号、成本相对低廉等优点，现行技术以荧光寿命型、稀土4f-4f谱线荧光强度比型技术为主，前者工程化较成功，但其测温范围、响应时间特性局限明显。针对医疗、航空、电力等行业对新型测温技术的需求，本项目开发稳态荧光的温度传感技术，基于固体光学原理提出了四类温度传感机制并于实验中验证了它们的性能，开发了谱重心、宽带强度比等高精度光谱数据分析方法，实现了普遍性的荧光材料温敏特性利用，设计制作了基于宽带荧光的荧光强度比型光纤温度传感器；此外，研究了应力、酸碱度、湿度、位置位移等各个其它环境参量对荧光光谱的影响，与荧光温度传感一起形成了全面的荧光式物理量传感技术方向。其中，温度传感实现了近10K低温到1000K以上高温的测温范围、0.1K的分辨率；荧光应力传感达到了2KPa的已知最精细分辨；位移传感达到亚微米分辨率@2.5cm量程。项目在荧光式传感技术领域形成了较全面的自主知识产权保护。项目成果不仅仅为荧光式传感成为类似半导体传感技术的独立学科方向打下基础，还为发光材料的高附加值利用开发了新的领域。