Exploring how a Conductive Polymer Emerges from its Component Polymer Molecules

非技术描述：这项研究考察了柔性、透明和导电聚合物的电学性能--这些材料对包括太阳能电池和便携式显示器在内的各种设备非常重要。虽然这种聚合物薄膜是由许多单独的分子组成的，但它们的光学和电学性质与它们孤立的分子组成有很大的不同。这项研究的目的是了解这些聚合物薄膜的性质是如何从它们的分子构件中出现的。具体地说，它的目的是阐明制备条件和分子之间的相互作用在有序结晶聚合物薄膜的电子性质出现中所起的作用。为了探索这一演变，该项目对单个聚合物分子以及不断增大的分子聚集体进行了光学测量。通过这种方式，从单个分子到有序薄膜，在不断增加的尺度上检查聚合物的电子性质。研究团队由来自不同背景的研究生和本科生组成。参与者接受材料科学、化学和光子学方面的培训。国际合作有助于加强研究工作和跨学科培训机会。此外，正在开发一个关于光子材料的教学模块。技术描述：共轭聚合物(CP)因其能够传导激子和电荷而具有重要的技术价值。这些材料的大多数器件应用都是利用聚合物薄膜。该项目需要使用最近开发的光谱工具来阐明薄膜电子行为是如何从其单个分子组成的属性以及分子间相互作用中出现的。具体地说，研究采用单分子光谱学来研究极化子的性质--共轭聚合物中的电荷载流子--其电子结构和分布对于确保最佳器件性能至关重要。实验包括一系列长度尺度的光谱研究，从孤立的聚合物，到球状和结构域，再到多域结构。以这种方式，可以识别出现膜状行为的临界长度尺度，以及影响该转变开始的控制参数。这项研究利用超高品质因数光学微谐振器作为电子和偏振光谱的平台，能够探测带电和导电的CP。通过研究光学性质、电子结构和分子有序性的相互作用，有可能构建一个详细的光子有机材料电子性质的模型。

Nontechnical description: This study examines the electrical properties of flexible, transparent and conductive polymers - materials of tremendous importance to a variety of devices including solar cells and portable displays. Although such polymer films are composed of numerous individual molecules, their optical and electronic properties are extremely different from those of their isolated molecular constituents. The study aims to understand how the properties of these polymeric films emerge from their molecular building blocks. Specifically, it aims to elucidate the role fabrication conditions and interactions between molecules play in the emergence of electronic properties of ordered, crystalline polymer films. To explore this evolution, the project implements optical measurements of single polymer molecules, as well as molecular aggregates of increasing size. In this manner, electronic properties of polymers are examined over increasing scales, ranging from individual molecules through ordered thin films. The research team comprises graduate students and undergraduate researchers from diverse backgrounds. Participants receive training in materials science, chemistry, and photonics. An international collaboration serves to enhance research efforts as well as interdisciplinary training opportunities. In addition, a teaching module on photonic materials is being developed. Technical description: Conjugated polymers (CPs) are technologically important due to their ability to conduct excitons and charge. Most device applications of these materials utilize thin polymeric films. This project entails the use of a recently developed spectroscopic tool to elucidate how thin film electronic behavior emerges from the properties of its individual molecular constituents, as well as from intermolecular interactions. Specifically, studies implement single-molecule spectroscopy to address the nature of polarons - charge carriers in conjugated polymers - whose electronic structure and distribution are critical for ensuring optimal device performance. Experiments encompass spectroscopic studies on a range of length scales, from isolated polymers, through globules and domains, to multi-domain structures. In this manner it is possible to identify the critical length scale over which film-like behavior emerges, and the control parameters influencing the onset of this transition. The study utilizes ultra-high quality-factor optical microresonators as platforms for electronic and polarization spectroscopy, enabling the probing of charged and conducting CPs. Through studies of the interplay of optical properties, electronic structure, and molecular ordering it is possible to construct a detailed model of the electronic properties of photonic organic materials.