CAREER: Solid State Solvation in Doped & Nanostructured Organic Thin Films: A Novel Method for Tailoring Energy Level Structure of Organic Materials in Active Optoelect. Devic

职业：掺杂中的固态溶剂化

• 批准号: 0093866
• 负责人: Vladimir Bulovic
• 金额: --
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-02-01 至 2006-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0093866&HistoricalAwards=false
• 关键词: CAREER; Solid; State; Solvation; Doped

Professor Vladimir Bulovic recently demonstrated a new general method for tuning theenergy level structure of organic materials by adjusting the strength of the local electricfield inside the organic films with intermolecular dipole-dipole interactions. His groupwill now apply this "solid state solvation" (SSS) effect to demonstrate practical, efficientorganic optoelectonic devices such as organic LEDs, lasers, and solar cells, and develop atheoretical understanding of this phenomenon. The SSS effect is present in everymolecular organic solid, but is most clearly observed in strongly polar materials andcomposites. It originates from dipole-dipole interactions between neighboring moleculesthat generate strong local electric fields, stretching the intramolecular bond lengths anddeforming charge distributions on molecules. This physical change in the molecularstructure is manifested in the modified energy level structure for the molecule, which wecan utilize to optimize performance of organic optoelectronic devices.Prof. Bulovic previously demonstrated that local electric fields generated in dipole-dipoleinteractions between polar organic molecules in a solid thin film can result in a shift ofmolecular energy levels by more than 0.25 eV, tuning the luminescence of the samemolecular species from yellow to orange to red. In this program his group will extend theinitial studies and utilize dipole-dipole interactions to tune the carrier injection propertiesat organic heterojunction interfaces, modify exciton energy transfer rates from the host tothe dopant in mixed organic layers, and access triplet energy levels in efficientphosphorescent organic materials. These effects will be optimized to improveluminescence efficiencies of organic LEDs, lower lasing thresholds of organic lasers, andincrease photogeneration efficiency of organic solar cells. The theoretical frameworkquantifying intermolecular interactions in molecular organic thin films is not presentlyknown and will be developed within this program.Findings discovered in the course of this program are fundamental in nature and will havea strong impact on practical applications of molecular organic solids in optoelectronicdevices. They will enhance the understanding and the applicability of the vast field ofmolecular organic materials, influencing treatment of organic thin films, heterojunctions,multilayers, quantum wells, and nano-patterned organic materials. These findings will beincorporated in the graduate "Seminar on Organic Optoelectronics" that Prof. Vulovic ispresently preparing for the MIT graduate curriculum.

弗拉基米尔·布洛维奇教授最近展示了一种新的通用方法，通过调节分子间偶极-偶极相互作用的有机膜内部的局部电场强度来调节有机材料的能级结构。他的团队现在将应用这种“固态溶剂化”（SSS）效应来展示实用，高效的有机光电器件，如有机LED，激光器和太阳能电池，并发展对这种现象的理论理解。SSS效应存在于每种分子有机固体中，但在强极性材料和复合材料中观察得最清楚。它起源于相邻分子之间的偶极-偶极相互作用，产生强的局部电场，拉伸分子内的键长并使分子上的电荷分布变形。分子结构的这种物理变化表现在分子能级结构的改变上，我们可以利用这种改变来优化有机光电器件的性能。Bulovic教授先前证明，在固体薄膜中极性有机分子之间的偶极-偶极相互作用中产生的局部电场可以导致分子能级移动超过0.25 eV，将相同分子种类的发光从黄色调谐到橙子再到红色。在这个项目中，他的团队将扩展最初的研究，并利用偶极-偶极相互作用来调整有机异质结界面处的载流子注入特性，改变混合有机层中从主体到掺杂剂的激子能量转移速率，并在高效磷光有机材料中获得三重态能级。这些效应将被优化以提高有机LED的发光效率，降低有机激光器的激光阈值，以及提高有机太阳能电池的光生效率。分子有机薄膜中分子间相互作用的定量理论框架目前还不清楚，将在本计划中得到发展。在本计划过程中发现的发现是基本的，将对分子有机固体在光电子器件中的实际应用产生强烈的影响。它们将增强对分子有机材料这一广阔领域的理解和应用，影响有机薄膜、异质结、多层膜、量子威尔斯和纳米图案化有机材料的处理。这些发现将被纳入研究生“有机光电子学研讨会”，Vulovic教授目前正在为麻省理工学院研究生课程做准备。