The Effects of Driving Force, Morphology and Anion Separation on Carrier Mobility in Doped Conjugated Polymers

驱动力、形态和阴离子分离对掺杂共轭聚合物中载流子迁移率的影响

• 批准号: 2105896
• 负责人: Benjamin Schwartz
• 金额: $ 60.5万
• 依托单位: University of California-Los Angeles
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-07-01 至 2025-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2105896&HistoricalAwards=false
• 关键词: Effects; Driving; Force; Morphology; Anion

Semiconductors are the basis for modern electronics such as computers, flat screen displays, and mobile phones. Most semiconductors are inorganic, hard materials such as silicon, and are expensive to process and manufacture. This project explores the properties of plastic semiconductors that are lightweight, flexible and potentially inexpensive to process. The electrical properties of inorganic semiconductors are controlled through doping. Doping is the intentional introduction of impurities into a semiconductor for the purpose of changing its electrical or optical properties. A key challenge facing the development of plastic semiconductors is they are not as easy to dope as inorganic semiconductors. This collaborative project takes advantage of new materials and processing methods to controllably dope plastic semiconductors. New materials have tunable properties that will allow for a greater degree of control over electrical conductivity. New processing methods allow dopant molecules to be precisely added to the plastic semiconductors at desired locations. High-quality doped polymer films will be studied by a suite of techniques to fully understand them. They will also be incorporated into thermoelectric devices that convert waste heat into electricity, a new source of renewable energy. Undergraduate and graduate students will be trained in areas of national need through this project. Outreach efforts will introduce high school students in the Los Angeles area to related topics such as renewable energy through demonstrations and experiments. This project is jointly funded by the Electronic and Photonic Materials program of the Division of Materials Research and the Chemical Structure, Dynamics, and Mechanisms B program of the Division of Chemistry. Conjugated polymers have numerous potential uses because they combine the mechanical properties of plastics with the electrical properties of semiconductors. When doped by strong oxidizing agents, their conductivity can be tuned by orders of magnitude, but interactions with the dopant counterion and dopant-induced changes in morphology can limit the doped carrier mobility. This project takes advantage of sequential processing, in which the polymer film is cast first and the dopant is infiltrated in a second step from a solvent chosen to appropriately swell but not dissolve the underlying polymer film. This method provides a degree of control over the doped polymer morphology that enables large-area applications, such as thermoelectric devices. The project also explores novel dopants, including newly-synthesized dodecaborane clusters with tunable redox potentials. These clusters have chemical structures that serve to shield the counterion charge from the polarons on the polymer backbone, allowing for control over the counterion-polaron interaction, and thus providing for improved carrier mobility and Seebeck coefficient. The project also investigates counterion exchange, where after reaction, the dopant counterion can be substituted for an inert ion by mass action, providing yet another degree of control over the properties of doped conjugated polymers. In all cases, the physical structure of the doped polymer film, as determined by a combination of grazing incidence wide angle X-ray scattering and neutron reflectometry, is correlated with the optical and electrical properties to understand how the location of the counterion in the film controls physical properties. Finally, the project uses ultrafast spectroscopy to measure both the thermal conductivity (via time-domain thermal reflectance) and electrical properties (via pump/probe transient absorption experiments) of doped conjugated polymer films. The key aim of the project is to determine detailed structure/function relationships to maximally exploit the use of doped conjugated polymers in thermoelectric and other devices.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

半导体是计算机、平板显示器和移动电话等现代电子产品的基础。大多数半导体是无机的、硬的材料，如硅，加工和制造成本很高。这个项目探索了塑料半导体的特性，这些特性是轻便、灵活的，而且加工成本可能不高。无机半导体的电学性质是通过掺杂来控制的。掺杂是有意将杂质引入半导体以改变其电学或光学性质。塑料半导体发展面临的一个关键挑战是，它们不像无机半导体那样容易掺杂。这个合作项目利用新材料和加工方法对塑料半导体进行可控掺杂。新材料具有可调节的特性，这将允许在更大程度上控制导电性。新的加工方法允许将掺杂剂分子精确地添加到塑料半导体中所需的位置。高质量的掺杂聚合物薄膜将通过一套技术进行研究，以充分了解它们。它们还将被整合到热电设备中，将废热转化为电力，这是一种新的可再生能源。通过该项目，将对本科生和研究生进行国家需要领域的培训。外展工作将通过演示和实验向洛杉矶地区的高中生介绍可再生能源等相关主题。该项目由材料研究部的电子和光子材料计划和化学部的化学结构、动力学和机制B计划共同资助。共轭聚合物有许多潜在的用途，因为它们结合了塑料的机械性能和半导体的电学性能。当被强氧化剂掺杂时，它们的电导率可以被调节几个数量级，但与掺杂剂反离子的相互作用和掺杂剂引起的形态变化会限制掺杂的载流子迁移率。该项目利用顺序工艺的优势，在顺序工艺中，首先浇注聚合物膜，然后在第二步中从选择的溶剂中渗透掺杂剂，以适当膨胀但不溶解下面的聚合物膜。这种方法提供了对掺杂聚合物形态的一定程度的控制，从而使大面积应用成为可能，例如热电设备。该项目还探索了新的掺杂剂，包括新合成的具有可调氧化还原电位的十二硼烷簇合物。这些团簇的化学结构用于保护反离子电荷不受聚合物主干上的极化子的影响，从而允许控制反离子-极化子相互作用，从而提供改进的载流子迁移率和塞贝克系数。该项目还研究了反离子交换，在反应后，掺杂剂反离子可以通过质量作用取代惰性离子，从而提供了对掺杂共轭聚合物性能的另一种程度的控制。在所有情况下，由掠入射广角X射线散射和中子反射仪相结合确定的掺杂聚合物薄膜的物理结构与光学和电学性质相关，以了解反离子在薄膜中的位置如何控制物理性质。最后，该项目使用超快光谱来测量掺杂共轭聚合物薄膜的导热系数(通过时域热反射)和电学性质(通过泵浦/探测瞬时吸收实验)。该项目的主要目标是确定详细的结构/功能关系，以最大限度地利用掺杂共轭聚合物在热电和其他设备中的使用。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Counterion Control and the Spectral Signatures of Polarons, Coupled Polarons, and Bipolarons in Doped P3HT Films

• DOI: 10.1002/adfm.202213652
• 发表时间: 2023-02
• 期刊: Advanced Functional Materials
• 影响因子: 19
• 作者: Eric C Wu;Charlene Z. Salamat;O. Ruiz;Thomas Qu;Alexis Kim;S. Tolbert;B. J. Schwartz

Tuning counterion chemistry to reduce carrier localization in doped semiconducting carbon nanotube networks

• DOI: 10.1016/j.xcrp.2023.101407
• 发表时间: 2023-05
• 期刊: Cell Reports Physical Science
• 影响因子: 8.9
• 作者: Tucker L. Murrey;Taylor J. Aubry;O. Ruiz;Kira A. Thurman;K. Eckstein;Evan A. Doud;Julia M. Stauber;A. Spokoyny;B. J. Schwartz;T. Hertel;J. Blackburn;Andrew J. Ferguson

Molecular Dynamics Study of the Thermodynamics of Integer Charge Transfer vs Charge-Transfer Complex Formation in Doped Conjugated Polymers

掺杂共轭聚合物中整数电荷转移与电荷转移络合物形成的热力学的分子动力学研究

• DOI: 10.1021/acsami.2c06449
• 发表时间: 2022
• 期刊: ACS Applied Materials & Interfaces
• 影响因子: 9.5
• 作者: Wu, Eric Chih-Kuan;Salamat, Charlene Z.;Tolbert, Sarah H.;Schwartz, Benjamin J.
• 通讯作者: Schwartz, Benjamin J.

Vibrational Stark Effect Mapping of Polaron Delocalization in Chemically Doped Conjugated Polymers

化学掺杂共轭聚合物中极化子离域的振动斯塔克效应图

• DOI: 10.1021/acs.chemmater.1c02934
• 发表时间: 2021
• 期刊: Chemistry of Materials
• 影响因子: 8.6
• 作者: Stanfield, Dane A.;Mehmedović, Zerina;Schwartz, Benjamin J.
• 通讯作者: Schwartz, Benjamin J.