In Operando Characterization of Degradation Processes in Organic Semiconductor Materials

非技术摘要有机半导体材料在光电子学、热电学、生物电子学以及能量采集和存储应用等许多现有和新兴技术中具有特殊的前景。在有机半导体的商业应用中，这些材料在使用过程中的降解是一个主要问题。这些退化途径被认为是暴露在环境大气中的少量气体和湿气以及紫外线辐射造成的复杂影响的组合。在固态和材料化学计划的支持下，这项基础性工作使基于光和电子与这些材料的相互作用的尖端、最先进的光谱工具得以开发，以确定伴随降解的化学路径，从而产生更好的解决方案来解决这个复杂的问题。这种跨学科的内在努力通过参与的研究生的专业发展产生了实质性的更广泛的影响。研究生在另一位首席研究员的实验室进行部分论文研究，并在Next Energy Technologies，Inc.完成为期6周的实习。技术摘要固态有机半导体材料是各种现有和新兴技术的基本有源元件，包括发光二极管激光器和基于有机的电子和光子设备。这些技术的寿命有限，因为有机半导体不可避免地通过定义不清的化学、光化学和光物理过程退化，特别是在操作过程中或在操作条件下。解决这些限制需要对这些有机半导体材料在降解过程中和降解后的分子结构、电子和电荷传输属性进行表征。为此，一系列最先进的方法，包括常压到超高真空下的表面振动光谱(拉曼，PM-IRRAS)，X射线光电子能谱(XPS)，紫外光电子能谱(UPS)，反向光电子能谱(IPES)和电荷迁移率测量，被用来研究有机半导体在化学和光电复杂性系统增加的环境中，包括在操纵腔中。这项工作的主要目标是对有机半导体器件性能下降和最终失效的化学、光化学和光物理降解机理进行全面的基础调查。这一努力的第二个影响是制定了更强大的有机半导体的新设计标准。

Non-technical AbstractOrganic semiconductor materials hold exceptional promise in a number of existing and emerging technologies including optoelectronics, thermoelectrics, bioelectronics, and energy harvesting and storage applications. Degradation of these materials during use is a major issue in the commercial implementation of organic semiconductors. These degradation pathways are thought to be a complex combination of effects resulting from exposure to small amounts of gases and moisture in the ambient atmosphere as well as ultraviolet radiation. With the support of the Solid State and Materials Chemistry program, this foundational effort allows development of sophisticated, state-of-the-art spectroscopic tools based on the interaction of light and electrons with these materials to identify the chemical pathways that accompany degradation, leading to better solutions to solve this complicated problem. This inherently interdisciplinary effort has substantial broader impact through the professional development of the graduate students involved. Graduate students conduct a portion of their dissertation research in the laboratory of the other Principal Investigator, as well as complete a 6-week internship at Next Energy Technologies, Inc. Technical AbstractSolid-state organic semiconductor materials are the essential active components of a variety of existing and emerging technologies, including light-emitting diode lasers and organic-based electronic and photonic devices. These technologies suffer from limited lifetimes due to the inevitable degradation of organic semiconductors through poorly defined chemical, photochemical and photophysical processes, especially in operando, or under conditions of operation. Addressing these limitations requires characterization of the molecular structural, electronic, and charge transport attributes of these organic semiconductor materials during and after degradation. Toward this end, a suite of state-of-the-art methods, including surface vibrational spectroscopies (Raman, PM-IRRAS) in ambient to ultrahigh vacuum, x-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), inverse photoemission spectroscopy (IPES), and charge mobility measurements, are used to study organic semiconductors in environments that systematically increase in chemical and optoelectronic complexity, including in operando. The primary objective of this effort is to undertake a comprehensive fundamental investigation of the chemical, photochemical, and photophysical mechanisms of degradation that underlie the diminished performance and eventual failure of organic semiconductor-based devices. The secondary impact of this effort is formulation of new design criteria for more robust organic semiconductors.