CAREER: Structure-Function-Property Relationships in Charged Conjugated Polymers

技术这个职业项目旨在了解用于塑料电子应用的带电共轭聚合物的结构-功能-性能关系。共轭聚合物(CP)是一种既具有半导体的光学和电学性能，又具有塑料的机械性能的材料。该项目的重点是对阳离子和阴离子共轭聚合物(共轭聚电解质)的光学和电学性质作为分子结构、电荷密度(每重复单位的电荷数量)、反离子类型和材料加工条件的基本了解。含有带电官能团的共轭聚合物的优势在于，它们可以很好地控制聚合物在溶液中的构象，从而控制薄膜中聚合物链的电子相互作用程度(链间相互作用)。这些链间相互作用对生物传感器、发光二极管(LED)、太阳能电池和场效应晶体管(FET)等基于CP的器件的光致发光量子产率和寿命、能量迁移和电荷迁移率等光学和电学性质和退化速率有很大的影响，从而影响器件的效率和工作寿命。方法是通过改变溶液中的溶剂、浓度、盐、官能团、电荷密度、共轭聚合物骨架和膜的形态来控制聚合物在溶液中的构象，通过聚合物构象、退火工艺和各种成膜方法来控制聚合物的构象。将使用光散射、稳态和时间分辨光谱、扫描探针技术(原子力显微镜、静电力显微镜和导电原子力显微镜)以及原型设备评估来全面了解聚合物的构象、薄膜形态、光学和电子性质以及纳米级和散体中的电荷传输，作为分子结构和加工条件的函数。具体目标包括：1)通过分子结构和加工条件了解和控制溶液中带电共轭聚合物的构象，以及聚合物构象的变化如何影响其光物理。2)了解和控制聚合物光物理和聚合物薄膜的电荷传输特性作为分子结构、电荷密度(每个重复单位的电荷数目)、反离子类型和工艺条件的函数。非技术性该项目的更广泛影响将是在加州大学伯克利分校和圣巴巴拉社区的研究和教育之间建立联系。研究生和本科生将是开展这项研究的关键。该研究计划促进了有机半导体领域研究生和本科生的教学、培训和学习。该研究是高度跨学科的；学生将接触到在材料设计和合成、材料表征以及器件制造和评估方面的广泛研究经验，这将为他们未来的职业生涯提供广度和灵活性。他们将发展化学、物理和材料科学方面的知识。为加强和更新UCSB科学课程中的新科学，PPI将开发几门研究生和本科生课程。通过UCSB的几个外展项目，PI将把暑期本科生、大学生和高中教师带到她的实验室参加研究活动。为了增加多样性，促进孩子们上大学和主修科学，国际学生联合会将参加科学技术日，这是一个一年一度的活动，将初中和高中的学生和教师带到南加州大学参加科学研讨会和比赛。

TechnicalThis CAREER project aims to understand the structure-function-property relationships in charged conjugated polymers for applications in plastic electronics. Conjugated polymers (CPs) are materials that have the optical and electrical properties of semiconductors with the mechanical properties of plastics. The project focus is on fundamental understanding of the optical and electronic properties of cationic and anionic conjugated polymers (conjugated polyelectrolytes) as a function of molecular structure, charge density (number of charge per repeat unit), type of counter ions, and material processing conditions. The advantage of conjugated polymers containing electrically charged functional groups is that they offer fine control of the polymer conformation in solution, and hence, the degree of electronic interaction of polymer chains in films (interchain interactions). These interchain interactions strongly influence optical and electronic properties and degradation rate such as photoluminescence quantum yield and lifetime, energy migration, and charge mobility in CP-based devices such as biosensors, light-emitting diodes (LEDs), solar cells, and field effect transistors (FETs), and so, the device efficiencies and operational lifetime. The approach is to control polymer conformation in solution by changing solvent, concentration, salt, functional group, charge density, and conjugated polymer backbone and film morphology by polymer conformation, annealing process, and various film fabrication methods. Light-scattering, steady-state and time-resolved spectroscopies, scanning probe techniques (Atomic Force Microscopy, Electrostatic Force Microscopy, and Conducting Atomic Force Microscopy), along with prototype device evaluation will be used to obtain a comprehensive understanding of polymer conformation, film morphology, optical and electronic properties, and charge transport at the nanoscale, and in bulk as a function of molecular structure and processing conditions. Specific goals include: 1) To understand and control charged conjugated polymer conformation in solution via molecular structure and processing conditions and how change in polymer conformation affects its photophysics. 2) To understand and control polymer photophysics and charge transport properties of polymer films as a function of molecular structure, charge density (number of charge per repeat unit), type of counter ions, and processing conditions. Non-TechnicalThe broader impact of the project will be the link established between research and education at UCSB and the Santa Barbara community. Graduate and undergraduate students will be essential to carrying out the research. The research plan promotes teaching, training, and learning of graduate and undergraduate students in the field of organic semiconductors. The research is highly interdisciplinary; students will be exposed to a wide range of research experience in material design and synthesis, materials characterization, and device fabrication and evaluation that will provide breadth and flexibility for their future careers. They will develop knowledge in chemistry, physics, and materials science. Several graduate and undergraduate courses will be developed by the PI to strengthen and update new science in the science curriculum at UCSB. Through several outreach programs at UCSB, the PI will bring summer undergraduate students, college students, and high school teachers to her laboratory to participate in research activities. To increase the diversity and to promote children to go to college and major in science, the PI will participate in Science and Technology Day, an annual event that brings students and teachers from middle and high schools to UCSB to participate in science workshops and competitions.