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

通过这一奖项，化学测量和成像计划支持华盛顿大学的菲利普·J·里德开发新的计算分析技术的研究，以更全面地了解电子光学设备中的分子是如何发出光的。这些系统在技术上很重要，在电信行业有很多用途，但人们仍然不知道为什么当它们连续被光照射时，设备中的分子会发出一阵阵光，而不是稳定的发光流。这种眨眼，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分析眨眼模式，以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。为这一分析而开发的新工具将能够量化分子环境变化引起的眨眼变化，而且也更容易实现。这项工作正在产生比现有技术快得多的分析方法。因此，通过开发适用于光子学、材料科学、电子学和生物学等多个领域的广泛测量的新工具，这项研究正在对技术和科学产生广泛影响。这项工作通过让参与这项研究的学生亲身体验先进技术，对未来一代科学家的培训产生了进一步广泛的影响。在这个项目中，正在开发强大的统计工具来分析光致发光间歇(PI，或更常见的“闪烁”)，以更全面地了解在连续照明下在单个发光体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。研究人员正在使用这些新开发的方法来测量非线性光学材料的光稳定性，以及介电环境对复杂凝聚相中生色团等电点的影响。从这类系统收集的PI数据经常显示出与幂定律分布的显著偏差，这使得发射事件动力学的分析变得复杂。这些新工具正在使用先进的贝叶斯统计模型，通过易于实现的代码集，扩展将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。新工具还使用累积分布泛函和核密度估计来扩展PI的分析，以允许将各种分布函数(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、同位素替代等)的影响进行统计稳健的评估。促进了光子材料的研究，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了一个重要的工具。

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.