Development and Application of New Tools for Analyzing Single Molecule Photoluminescence Intermittency

有了这个奖项，化学测量和成像项目正在支持华盛顿大学的Phillip J. Reid的研究，以开发新的计算分析技术，更全面地了解电子光学设备中分子是如何发射光的。这些系统在技术上很重要，在电信工业中有很多用途，但人们仍然不明白为什么当它们连续被光照射时，设备中的分子会发出阵阵光，而不是稳定的发射光流。这种闪烁，也被称为光致发光间歇性（PI），似乎也受到这些分子周围环境的强烈影响。研究人员正在使用数学方法来分析眨眼模式，以便了解眨眼本身的起源以及分子周围的环境如何影响眨眼模式。为这种分析开发的新工具将能够量化由分子环境变化引起的闪烁变化，并且也更容易实现。这项工作正在产生比现有技术快得多的分析方法。因此，该研究通过开发新工具对技术和科学产生了广泛的影响，这些工具将适用于许多领域的广泛测量，包括光子学，材料科学，电子学和生物学。这项工作通过给参与这项研究的学生提供先进技术的实践经验，对培养下一代科学家产生了进一步的广泛影响。在这个项目中，正在开发用于分析光致发光间歇性（PI，或更常见的“闪烁”）的强大统计工具，以更充分地了解在连续照明下单个发光团中观察到的发射和非发射状态之间的变化。这项工作涉及研究复杂系统中单分子发出的光，包括聚合物复合材料和有机光子材料。研究人员正在利用这些新开发的方法来测量非线性光学材料的光稳定性和介电环境对复杂凝聚相中发色团PI的影响。从这样的系统中收集的PI数据通常表现出与幂律分布的显著偏差，使发射事件动力学的分析复杂化。新工具使用先进的贝叶斯统计模型扩展了将PI轨迹解析为发射和非发射事件的方法，其速度大约比当前最先进的变化点检测快一个数量级，通过一个易于实现的代码集。新工具还使用累积分布函数和核密度估计来扩展PI分析，以允许各种分布函数（参数和非参数）与实验数据进行定量比较。这种方法允许对扰动（温度，同位素取代等）对PI的影响进行统计上的可靠评估，推进光子材料的研究，并为其他试图将光物理过程与PI联系起来的研究人员提供重要工具。

With this award, the Chemical Measurements and Imaging Program is supporting the research of Phillip J. Reid of the University of Washington to develop new computational analysis techniques to more fully understand how light is emitted by molecules in electronic optical devices. These systems are technologically important and find many uses in the telecommunications industry, but it is still not understood why, when they are continuously illuminated by light, the molecules in the device respond by giving off bursts of light, rather than a steady stream of emitted light. This blinking, also known as photoluminescence intermittency (PI), also appears to be strongly affected by the environment surrounding these molecules. The investigators are using mathematical methods to analyze the blinking patterns in order to understand both the origin of the blinking itself as well as how the environment around the molecules affects the blinking pattern. The new tools being developed for this analysis will be able to quantify changes in blinking induced by changes in the molecule's environment and will also be easier to implement. The work is producing analysis methods that are much faster than existing techniques. Thus, the research is having a broad impact on technology as well as science through the development of new tools that will be applicable to a wide range of measurements in many fields including photonics, materials science, electronics, and biology. The work is having a further broad impact on the training of the future generation of scientists by giving students involved in this research hands-on experience with advanced techniques.In this project, robust statistical tools for analyzing photoluminescence intermittency (PI, or more commonly "blinking") are being developed to more fully understand the variation between emissive and non-emissive states observed in single luminophores under continuous illumination. The work involves the study of light emitted by single molecules in complex systems, including polymer composites and organic photonic materials. The investigators are using these newly developed methods to measure the photostability of nonlinear optical materials and the impact of dielectric environment on the PI of chromophores in complex condensed phases. PI data collected from such systems often exhibit significant deviations from power law distributions, complicating the analysis of emissive event kinetics. The new tools are using advanced Bayesian statistical models to extend approaches for parsing PI traces into emissive and non-emissive events at rates roughly an order of magnitude faster than Change Point Detection, the current state of the art, via a code set that is easily implemented. The new tools also use cumulative distribution functionals and kernel density estimation to expand analysis of PI to allow for a variety of distribution functions (parametric and non-parametric) to be quantitatively compared to experimental data. This approach allows for a statistically robust evaluation of the effect of perturbation (temperature, isotopic substitution, etc.) on PI, advancing studies of photonic materials and providing an important tool for other researchers trying to connect photophysical processes to PI.