In-situ and Operando Studies of Metastable and Transient States of Organic Semiconductor Thin Films

有机半导体薄膜亚稳态和瞬态的原位和操作研究

• 批准号: 1701774
• 负责人: Randall Headrick
• 金额: $ 42万
• 依托单位: University of Vermont & State Agricultural College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-07-01 至 2023-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1701774&HistoricalAwards=false
• 关键词: situ; Operando; Studies; Metastable; Transient

Nontechnical Description: Organic semiconductors are designed at the molecular level to exhibit useful properties, and they promise the realization of a new generation of electronic circuits and solar cells. This research activity utilizes highly controllable methods of depositing ordered crystalline thin films from liquid solutions bearing small organic molecules. Experiments are being performed to understand ways that molecules organize from a disordered solution state into highly ordered crystalline solids. These molecular arrangements can also be sensitively tuned by stretching or compressing thin films, which may dramatically affect their properties. The experiments utilize polarized optical microscopy and X-ray scattering - two techniques which can help determine molecular ordering in the films. Electronic measurements are used to determine how easily electrons move in these materials. Calculations are also being performed to test theoretical predictions of the link between the molecular arrangement and electron motion. The societal impact of the research is amplified by innovative community outreach activities, including lectures and demonstrations designed to engage the public in a discussion of science and applications of energy, light, and nano-materials. This project provides graduate student training in a highly interdisciplinary area, and it introduces undergraduate students to X-ray science and thin film deposition technology.Technical Description: The rectangular hollow pen writer method can produce highly oriented films with controllable grain size that can exceed one centimeter, while in comparison, vapor deposited films typically have randomly oriented nanometer-scale grains. This project involves studies of the relationships between process parameters and film properties, such as grain size and orientation, strain, and defect density. Recent work suggests that many small molecule materials pass through a precursor stage during crystallization from solution, and this state can be unambiguously observed through a combination of optical and X-ray studies. Polarized optical video microscopy is sensitive to the nucleation and development of grain structure, while real-time optical spectroscopy is highly sensitive to local ordering, such as aggregation and molecular packing geometries. Real-time synchrotron X-ray diffraction is highly complementary because it is sensitive to long-range order, allowing time-resolved studies with millisecond resolution. Carrier transport in organic field effect transistors will also be studied as a function of applied strain by elastic stretching of thin films and substrates. The results will be related to ab-initio studies of the effect of strain on the electronic band structure and carrier transport properties. This research may lead to new environmentally responsible manufacturing methods based on roll-to-roll processes. These methods will underpin new technologies for low-cost, flexible electronics and solar cells.

非技术描述：有机半导体在分子水平上被设计成具有有用的特性，它们有望实现新一代的电子电路和太阳能电池。这项研究活动利用高度可控的方法，从含有小有机分子的液体溶液中沉积有序的晶体薄膜。人们正在进行实验，以了解分子从无序的溶液状态组织成高度有序的结晶固体的方式。这些分子排列也可以通过拉伸或压缩薄膜来灵敏地调整，这可能会显着影响它们的特性。该实验利用偏光显微镜和X射线散射-两种技术，可以帮助确定膜中的分子排序。电子测量用于确定电子在这些材料中移动的容易程度。计算也正在进行，以测试分子排列和电子运动之间的联系的理论预测。研究的社会影响通过创新的社区外展活动得到放大，包括旨在让公众参与讨论科学和能源，光和纳米材料应用的讲座和演示。该项目提供跨学科的研究生培训，并向本科生介绍X射线科学和薄膜沉积技术。技术说明：矩形空心笔写入法可以生产高度取向的薄膜，其晶粒尺寸可以超过1厘米，而相比之下，气相沉积薄膜通常具有随机取向的纳米级晶粒。该项目涉及工艺参数和薄膜性能之间的关系的研究，如晶粒尺寸和取向，应变和缺陷密度。最近的工作表明，许多小分子材料在从溶液结晶期间通过前体阶段，并且这种状态可以通过光学和X射线研究的组合明确地观察到。 偏振光学视频显微镜是敏感的成核和晶粒结构的发展，而实时光学光谱是高度敏感的局部有序，如聚集和分子堆积的几何形状。 实时同步辐射X射线衍射是高度互补的，因为它对长程有序敏感，允许毫秒分辨率的时间分辨研究。有机场效应晶体管中的载流子输运也将通过薄膜和衬底的弹性拉伸作为施加应变的函数进行研究。这些结果将与应变对电子能带结构和载流子输运性质影响的从头算研究有关。这项研究可能会导致新的环境负责的生产方法的基础上卷到卷的过程。 这些方法将为低成本、柔性电子和太阳能电池的新技术奠定基础。

项目成果

Dynamic processes in transient phases during self-assembly of organic semiconductor thin films

有机半导体薄膜自组装过程中瞬态动态过程

• DOI: 10.1039/d1me00078k
• 发表时间: 2022
• 期刊: Molecular Systems Design & Engineering
• 影响因子: 3.6
• 作者: Wan, Jing;Li, Yang;Benson, Jared;Miller, Richards;Zhernenkov, Mikhail;Freychet, Guillaume;Headrick, Randall L.
• 通讯作者: Headrick, Randall L.

Enhancement of charge transfer in thermally-expanded and strain-stabilized TIPS-pentacene thin films

• DOI: 10.1103/physrevresearch.2.033294
• 发表时间: 2020-08-24
• 期刊: PHYSICAL REVIEW RESEARCH
• 影响因子: 4.2
• 作者: Li, Yang;Wan, Jing;Headrick, Randall L.
• 通讯作者: Headrick, Randall L.