Wamsley Max, Peng Weiyu, Tan Weinan, Wathudura Pathum, Cui Xin, Zou Shengli, Zhang Dongmao
Department of Chemistry, Mississippi University, Mississippi State, Mississippi 39759, United States.
Department of Chemistry, University of Central Florida, Orlando, Florida 32816, United States.
ACS Meas Sci Au. 2022 Sep 21;3(1):10-20. doi: 10.1021/acsmeasuresciau.2c00047. eCollection 2023 Feb 15.
Quantification of the temperature effects on the optical properties of photoluminescent (PL) materials is important for a fundamental understanding of both materials optical processes and rational PL materials design and applications. However, existing techniques for studying the temperature effects are limited in their information content. Reported herein is a temperature-dependent total photoluminescence (TPL) spectroscopy technique for probing the temperature dependence of materials optical properties. When used in combination with UV-vis measurements, this TPL method enables experimental quantification of temperature effects on fluorophore fluorescence intensity and quantum yield at any combination of excitation and detection wavelengths, including the fluorophore Stokes-shifted and anti-Stokes-shifted fluorescence. All model polyaromatic hydrocarbon (PAH) and xanthene fluorophores exhibited a strong excitation- and emission-wavelength dependence in their temperature effects. However, the heavy-atom effects used for explaining the strong temperature dependence of brominated anthracenes are not operative with xanthene fluorophores that have heavy atom substitutions. The insights from TPL measurements are important not only for enhancing the fundamental understandings of the materials photophysical properties but also for rational measurement design for applications where the temperature sensitivity of the fluorophore fluorescence is critical. An example application is demonstrated for developing a sensitive and robust ratiometric fluorescence thermometric method for real-time monitoring of sample temperatures inside a fluorescence cuvette placed in a temperature-controlled sample holder.
量化温度对光致发光（PL）材料光学性质的影响，对于从根本上理解材料的光学过程以及合理设计和应用PL材料而言至关重要。然而，现有的研究温度效应的技术在信息含量方面存在局限性。本文报道了一种用于探测材料光学性质温度依赖性的温度相关全光致发光（TPL）光谱技术。当与紫外可见光谱测量结合使用时，这种TPL方法能够在激发和检测波长的任何组合下，对温度对荧光团荧光强度和量子产率的影响进行实验量化，包括荧光团的斯托克斯位移和反斯托克斯位移荧光。所有模型多环芳烃（PAH）和呫吨荧光团在其温度效应方面均表现出强烈的激发波长和发射波长依赖性。然而，用于解释溴化蒽强烈温度依赖性的重原子效应，对于具有重原子取代的呫吨荧光团并不适用。TPL测量所得的见解不仅对于加深对材料光物理性质的基本理解很重要，而且对于荧光团荧光温度敏感性至关重要的应用中的合理测量设计也很重要。展示了一个示例应用，即开发一种灵敏且稳健的比率荧光测温方法，用于实时监测置于温度控制样品架中的荧光比色皿内样品的温度。
