Materials World Network: Understanding the Design and Characterization of Air-Stable N-Type Charge Transfer Dopants for Organic Electronics

技术概述：电荷转移掺杂是实现高效有机发光二极管和有机太阳能电池的关键，也是控制有机场效应晶体管电学特性所必需的。尽管p型掺杂剂的发展已经取得了很大进展，但由于对详细掺杂机理的了解有限，仍然缺乏有效的空气稳定溶液可加工的n型掺杂剂。为了解决这一问题，该材料世界网络项目由固体与材料化学项目和材料研究部特殊项目办公室支持，旨在a)了解以（1,3-二甲基-2,3-二氢- h -苯并咪唑-2-基）苯基（DMBI）为模型体系的一类有前途的掺杂剂的空气稳定n型掺杂剂的设计规则；b)了解n型掺杂的详细掺杂机制。参与该项目的三个小组具有独特的互补专业知识组合。Bao团队将合成具有系统不同能级和取代基的DMBI掺杂剂，以更好地与基体混溶，以帮助理解掺杂机制。用紫外-可见-近红外光谱和电子顺磁共振研究了掺杂的化学过程。掺杂层的形貌将通过原子力显微镜、各种x射线技术和纳米sims进行研究。德国的Leo小组将通过阻抗谱、紫外光电子能谱、塞贝克测量和主方程模型对电荷输运特性建模来研究掺杂的物理机制。将对空气稳定性进行测试，这些掺杂剂将用于最先进的有机器件，如发光二极管、太阳能电池或晶体管。最后，德国的Cuniberti团队将通过高分辨率扫描隧道显微镜在单分子水平上研究掺杂效应，并基于密度泛函理论通过从头计算模拟掺杂过程。非技术概述：电荷转移掺杂是实现高效显示器、固态照明、有机太阳能电池的关键，也是控制有机场效应晶体管电学特性所必需的。尽管p型掺杂剂的发展已经取得了很大进展，但由于对详细掺杂机理的了解有限，仍然缺乏有效的空气稳定溶液可加工的n型掺杂剂。这个材料世界网络项目将通过化学/化学工程、基础物理和理论等学科的国际合作，促进对兴奋剂的化学和物理的理解。这些发现将有助于更好地理解稳定高效的n掺杂剂和更高效的器件的设计规则。该项目将培养具有扎实基础知识和全球经验的学生和博士后。该项目将有助于促进有机电子领域和相关产业的发展，从而促进经济增长。这个项目将培养学生接触跨学科研究和不同的文化。鲍将与斯坦福国家科学基金会中心和科学推广办公室密切合作，接触到广泛的人群，包括K-12，社区学院，本科生和研究生，并为未来的科学和技术新领域的教师做好准备。

TECHNICAL SUMMARYCharge transfer doping is crucial in enabling highly efficient organic light emitting diodes and organic solar cells, and is needed for controlling the electrical characteristics of organic field effect transistors. Whereas the development of p-type dopants is well advanced, there is still a lack of effective air-stable solution processabile n-type dopants, due to limited knowledge on the detailed doping mechanisms. To address this gap, this Materials World Network project, supported by the Solid State and Materials Chemistry program and the Office of Special Programs, Division of Materials Research, aims at a) understanding the design rules for air-stable n-dopants based on a promising class of dopants with (1,3-dimethyl-2,3-dihydro-1H-benzoimidazol-2-yl)phenyl (DMBI) as the model system and b) understanding the detailed doping mechanisms of n-type doping. The three groups involved in the project have a unique combination of complementary expertise. The Bao group will synthesize DMBI dopants with systematically varied energy levels and substituents for better miscibility with the matrix to aid the understanding of doping mechanisms. The chemical process of doping will be investigated with UV-vis-NIR and electron paramagnetic resonance. The morphology of doped layers will be studied by atomic force microscopy, various X-ray techniques and nanoSIMS. The Leo group in Germany will study the physical mechanisms of doping by impedance spectroscopy, ultraviolet photoelectron spectroscopy, the Seebeck measurement, and modeling of the charge transport characteristic by a master equation model. The air-stability will be tested and the dopants will be used in state-of-the art organic devices such as light emitting diodes, solar cells, or transistors. Finally, the Cuniberti group in Germany will study the doping effect on a single molecular level by high resolution scanning tunneling microscopy and will model the doping process by ab initio calculations based on density functional theory. NON-TECHNICAL SUMMARY: Charge transfer doping is crucial in enabling highly efficient displays, solid-state lighting, organic solar cells, and is needed for controlling the electrical characteristics of organic field effect transistors. Whereas the development of p-type dopants is well advanced, there is still a lack of effective air-stable solution processabile n-type dopants, due to limited knowledge on the detailed doping mechanisms. This Materials World Network project will advance the understanding of the chemistry and physics of doping through an international co-operation across the disciplines of chemistry/ chemical engineering, fundamental physics and theory. These findings will lead to better understanding of design rules for stable and efficient n-dopants and more efficient devices. This project will train students and postdocs with a solid fundamental understanding as well as a global experience. This project will help to foster economic growth by furthering the field of organic electronics and the associated industry. This project will train students with exposure to interdisciplinary research and diverse cultures. Bao will work closely with Stanford NSF centers and Office of Science Outreach to reach out to a broad population ranging from K-12, community college, undergraduate, and graduate students, as well as prepare the teachers of tomorrow for new areas of science and technology.