FRG: Excitation Dynamics and Laser Action in Systems of Pi-Conjugated Materials

该项目是犹他大学物理系的研究人员在有机材料科学、运输与器件物理、光学和光电子学以及理论物理方面的专业知识的合作成果。项目研究目标：合成和生长新型半导体偶联有机晶体和自组装聚合物薄膜；非典型谐振腔有机光电器件和微激光器的制备、应用与理论并研究了这些体系的光激发动力学、激光作用和载流子性质。该方法是研究π共轭聚合物和长低聚物，形成自组装的二维片层和/或其他高度平面链形态的自旋铸造薄膜，以及低聚物，丙烯酸酯及其合金的新型单晶。这些聚合物薄膜和单晶可以在非常低的缺陷密度下生长，从而大大增加了它们的载流子迁移率。研究了低激发强度下聚合物薄膜和单晶中激子和极化子对的光生和动力学，高激发强度下激子和极化子的受激辐射的形成、激光作用和激子非线性过程。此外，有机发光二极管（OLED）和场效应晶体管（FET）将使用自组装聚合物薄膜和单晶制造，以及使用新的光谱技术研究注入OLED活性材料和FET沟道晶体管的载流子的性质。各种不同寻常的微激光谐振器将被制造，测试和研究实验和理论。其中包括随机形成的谐振腔，它在π共轭薄膜和渗透蛋白石中产生随机激光现象；形成混沌和稳定激光模式的非对称谐振器，其方向性优于现有的微盘激光谐振器；以及二维光子晶体，这些光子晶体将使用电子束光刻技术直接在有机晶体上作图。该项目涉及与技术相关的电子/光子材料科学热点领域的基础研究问题。该项目的一个重要特点是高度重视教育，并将研究与教育相结合。综合资源，包括晶体生长、聚合物合成、实验和理论物理方法、器件制造、加工和测试，为从事高度跨学科前沿研究的博士后、研究生和本科生提供了特殊的教育和培训机会

This project is a collaborative effort among researchers at the University of Utah Physics De-partment with expertise in Organic Materials Science, Transport and Device Physics, Optics and Optoelectronics, and Theoretical Physics. The project research goals are the synthesis and growth of novel semiconductor pi-conjugated organic crystals and self-assembled polymer thin films; fabrication, applications and theory of organic optoelectronic devices and microlasers with un-usual resonators; and study of the photoexcitation dynamics, laser action and charge carrier prop-erties in these systems. The approach is to study pi-conjugated polymers and long oligomers that form self assembled 2D lamellae and/or other highly planar chain morphologies in spin cast films, as well as novel single crystals of oligomers, acenes, and their alloys. These polymer films and single crystals can be grown with very low defect densities, consequently substantially in-creasing their carrier mobilities. The photogeneration and dynamics of excitons and polaron pairs in the polymer films and single crystals at low excitation intensities, the formation of stimulated emission, laser action and exciton nonlinear processes at high excitation intensities will be stud-ied. Additionally, organic light emitting diodes (OLED) and field effect transistors (FET) will be fabricated using self-assembled polymer films and single crystals, along with study of the prop-erties of carriers injected into the OLED active material and FET channel transistor using a novel spectroscopic technique. A variety of unusual microlaser resonators will be fabricated, tested and investigated experimentally and theoretically. These include randomly formed resonators, which give rise to the phenomenon of random lasers in pi-conjugated films and infiltrated opals; asym-metric resonators that form both chaotic and stable laser modes with improved directionality over existing microdisk laser resonators; and 2D photonic crystals that will be directly patterned onto the organic crystals using electron beam lithography. %%% The project addresses fundamental research issues in topical areas of electronic/photonic materi-als science having technological relevance. An important feature of the project is the strong em-phasis on education, and the integration of research and education. The combined resources, in-cluding crystal growth, polymer synthesis, experimental and theoretical physics methods, device fabrication, processing and testing, provide special opportunities for education and training of post doctoral associates, graduate and undergraduate students involved in highly interdisciplinary forefront research.***