Photophysics of Conjugated Polymer Thin Films and Semiconducting Single-Walled Carbon Nanotubes

共轭聚合物薄膜和半导体单壁碳纳米管的光物理

• 批准号: 0705163
• 负责人: Sumitendra Mazumdar
• 金额: $ 33.6万
• 依托单位: University of Arizona
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-01 至 2012-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0705163&HistoricalAwards=false
• 关键词: Photophysics; Conjugated; Polymer; Thin; Films

TECHNICAL SUMMARY:The Division of Materials Research and the Chemistry Division contribute funds to this award. This award supports theoretical and computational research and education on the photophysics of (1) thin films of -conjugated polymers, and (2) semiconducting single-walled carbon nanotubes.In (1), the PI aims to understand the mechanism of charge generation in thin films of (a) single-component polymers as well as (b) heterostructures consisting of polymer blends. The PI will investigate the roles of morphology and interchain interactions, and develop a theory that will describe simultaneously excitons, excimers and exciplexes, and free and bound polaron pairs. In the single-component polymers the PI aims to resolve an old controversy regarding the origin of polaron-derived states in thin films near the optical threshold. The PI hypothesizes that photoexcitation in the presence of significant interchain interactions leads to branching and generates a polaron-pair state directly.The PI will perform calculations on simplified models to support this key idea and propose further detailed calculations. In the polymer blends the PI notes that the binding energy of the interchain exciton generated by charge-transfer or the wavelength dependence of the charge generation cannot be understood within the simple wisdom that the band offset be larger than the binding energy of the intrachain exciton. Calculations for the single-component systems will be extended to the blends.In (2) the PI has two broad goals. The first is to reach quantitative understanding of the nonlinear and modulation optical spectroscopic experiments that are being performed for chirally enriched specific nanotubes. The PI aims to quantitatively understand (a) the energetics of the low-energy dark excitons, (b) the Aharonov-Bohm effect in semiconducting nanotubes and the transfer of oscillation strength from the bright to the dark exciton in magneto-optic spectroscopy, (c) optical absorptions polarized transverse to the nanotube axis, and (d) electroabsorpion. The second goal is to develop sophisticated theoretical and computational techniques to understand the physics of higher energy excitons and even multiexcitons.Graduate students and the postdoctoral fellow working on the project will gain experience at the interface of physics, chemistry and optics. An undergraduate student will also be involved in the research. Exciting new research results will be incorporated into an interdisciplinary graduate course. The P.I. participates as a mentor in the Student Exit Project in the Cienaga High School in Vail, Arizona. In addition, one to two presentations per year on careers in science in the same high school are planned. The P.I. also participates in a Binational Consortium in Optics, which involves exchange of information with scientists and students from Institutes in Mexico. Existing international cooperation with scientists in India will be continued. New international collaborations with scientists from India as well as Italy are being initiated.NON-TECHNICAL SUMMARY:The Division of Materials Research and the Chemistry Division contribute funds to this award. This award supports theoretical and computational research and education seeking to understand how light interacts with nanostructures, particularly large molecules and carbon nanotubes. The PI uses computer simulation and theory to gain insight at a microscopic level. The interactions between electrons in these nanostructures can be very strong and lead to new effects, novel microscopic processes, or unusual optical properties. During the past twenty years conjugated polymers and molecules have evolved from laboratory curiosities to key new optical materials. The work supported by this award is interdisciplinary involving condensed matter physics and materials chemistry. It contributes to the intellectual base from which of new technologies for nanoscale electronics, computation, and nanostructured materials may emerge.Graduate students and the postdoctoral fellow working on the project will gain experience at the interface of physics, chemistry and optics. An undergraduate student will also be involved in the research. Exciting new research results will be incorporated into an interdisciplinary graduate course. The P.I. participates as a mentor in the Student Exit Project in the Cienaga High School in Vail, Arizona. In addition, one to two presentations per year on careers in science in the same high school are planned. The P.I. also participates in a Binational Consortium in Optics, which involves exchange of information with scientists and students from Institutes in Mexico. Existing international cooperation with scientists in India will be continued. New international collaborations with scientists from India as well as Italy are being initiated.

技术摘要：材料研究部和化学部为该奖项提供资金。 该奖项支持（1）共轭聚合物薄膜和（2）半导体单壁碳纳米管的光物理学理论和计算研究和教育。在（1）中，PI旨在了解（a）薄膜中电荷产生的机制单组分聚合物以及（B）由聚合物共混物组成的异质结构。PI将研究形态和链间相互作用的作用，并开发一个理论，同时描述激子，准分子和激基复合物，自由和束缚极化子对。在单组分聚合物中，PI的目的是解决一个关于薄膜中极化子衍生态在光阈值附近起源的老争论。PI假设在存在显著链间相互作用的情况下光激发导致分支并直接产生极化子对态。PI将在简化模型上进行计算以支持这一关键想法，并提出进一步的详细计算。在聚合物共混物中，PI指出，电荷转移产生的链间激子的结合能或电荷产生的波长依赖性不能在带偏移大于链内激子的结合能的简单智慧内理解。 单组分体系的计算将扩展到共混物。在（2）中，PI有两个广泛的目标。首先是达到定量的非线性和调制光学光谱实验，正在进行的手性富集特定的纳米管的理解。PI的目的是定量地了解（a）低能量暗激子的能量，（B）半导体纳米管中的Aharonov-Bohm效应和磁光光谱中从亮激子到暗激子的振荡强度转移，（c）横向于纳米管轴偏振的光激发，以及（d）电激子。第二个目标是发展复杂的理论和计算技术，以理解更高能量激子甚至多激子的物理学。研究生和博士后研究员将在物理，化学和光学的界面上获得经验。一名本科生也将参与这项研究。令人兴奋的新研究成果将被纳入跨学科的研究生课程。私家侦探作为导师参加亚利桑那州韦尔市谢纳加高中的学生退出项目。此外，还计划每年在同一所高中举办一至两次关于科学职业的介绍会。私家侦探还参加了两国光学联合会，其中涉及与墨西哥各研究所的科学家和学生交流信息。与印度科学家的现有国际合作将继续下去。与印度和意大利科学家的新的国际合作正在启动。非技术性摘要：材料研究部和化学部为该奖项提供资金。 该奖项支持理论和计算研究和教育，旨在了解光如何与纳米结构相互作用，特别是大分子和碳纳米管。PI使用计算机模拟和理论来获得微观层面的洞察力。这些纳米结构中电子之间的相互作用可能非常强烈，并导致新的效应，新的微观过程或不寻常的光学特性。 在过去的二十年里，共轭聚合物和分子已经从实验室的好奇心发展到关键的新光学材料。该奖项支持的工作是跨学科的，涉及凝聚态物理和材料化学。该项目为纳米电子、计算和纳米结构材料的新技术的出现奠定了知识基础。研究生和博士后将在该项目中获得物理、化学和光学的经验。一名本科生也将参与这项研究。令人兴奋的新研究成果将被纳入跨学科的研究生课程。私家侦探作为导师参加亚利桑那州韦尔市谢纳加高中的学生退出项目。此外，还计划每年在同一所高中举办一至两次关于科学职业的介绍会。私家侦探还参加了两国光学联合会，其中涉及与墨西哥各研究所的科学家和学生交流信息。与印度科学家的现有国际合作将继续下去。目前正在与印度和意大利的科学家开展新的国际合作。