Synthetic and Mechanistic Studies of Air-Stable Organometallic Dimers as n-Dopants for Organic Electronics

技术总结这项研究项目由固体和材料化学以及电子和光子材料计划共同支持。电荷传输材料的掺杂可以极大地改善有机电子器件的性能。适用于典型的电子传输材料的氮掺杂，如果通过简单的电子转移反应，必然是气敏的。空气稳定的前驱体在薄膜沉积期间或之后形成掺杂剂的方法可以简化器件制造。PI最近证明，某些夹心化合物的空气稳定二聚体，如罗多烯，可以掺杂材料，形成相应的单体夹心阳离子。与其他空气稳定的分子n掺杂前驱体方法相比，副反应可能被最小化，并且可以掺杂电子亲和势低得多的材料(到目前为止为2.8 eV)。这项提议旨在详细了解这些二聚体的化学组成，并扩大它们的用途。我们将利用溶液浇铸薄膜的合成、核磁共振交叉实验、动力学的Vis-NIR监测以及XPS、UPS和电导率研究来确定：在不显著影响二聚体空气稳定性的情况下使用这种方法掺杂的限度；如何控制掺杂速率以允许在空气中溶液浇铸薄膜，并随后激活掺杂；以及相关的3D金属络合物二聚体甚至全有机二聚体在多大程度上可以取代重金属二聚体。非技术性总结人们对轻巧灵活的电子设备(显示器、照明设备、太阳能电池)有广泛的兴趣，这些设备可以低成本和低温度制造。这些材料使用有机(含碳)分子或聚合物来取代传统的半导体，使用掺杂剂可以大大改善其电学性能，从而增加(N)或减少(P)材料中的电子数量。N-掺杂剂通常具有很高的活性，这使得它们的使用变得复杂。PI已经发现了n-掺杂剂，这种掺杂剂非常稳定，但却掺杂了许多材料。这一计划将使人们能够更好地了解和控制这些掺杂剂、相关的掺杂剂及其反应性，并可能导致更高效的设备。学生将接受有机电子材料的培训，更广泛地说，将在调查科学问题方面进行培训，案例研究将用于PIS的讲课。私人投资机构将通过以下方式教育和培训妇女和代表不足的少数群体：接待暑期学生并鼓励他们申请研究生院，通过在HBCU和其他为少数群体服务的机构举办研讨会招募人才，以及参加有大量少数群体参与的讲习班和会议。PIs与新墨西哥高地大学NSF Prem的合作将得到支持；那里的学生将确定新掺杂剂的结构，PIs将讲授将化学和应用联系起来的课程。

TECHNICAL SUMMARYThis research project is jointly supported by the Solid State and Materials Chemistry and the Electronic and Photonic Materials Programs. Doping of charge-transport materials can greatly improve the behavior of organic electronic devices. n-Dopants suitable for typical electron-transport materials are inevitably air-sensitive if reacting by simple electron transfer. Approaches in which air-stable precursors form dopants during, or subsequent to, film deposition can simplify device fabrication. The PIs recently demonstrated that air-stable dimers of certain sandwich compounds, such as rhodocene, can n-dope materials, forming the corresponding monomeric sandwich cations. In contrast to other air-stable precursor approaches to molecular n-dopants, side reactions are likely to be minimized and materials with much lower electron affinities (2.8 eV to date) can be doped. This proposal aims to understand the chemistry of these dimers in detail and to broaden their utility. Synthesis, NMR crossover experiments, vis-NIR monitoring of kinetics, and XPS, UPS, and conductivity studies of solution-cast films will be used to establish: the limits of doping using this approach without significantly compromising the dimer air-stability; how the rate can be controlled to permit solution-casting of films in air, with subsequent dopant activation; and the extent to which heavy-metal dimers can be replaced by related dimers of 3d-metal complexes or even all-organic dimers. NON-TECHNICAL SUMMARYThere is wide interest in lightweight-flexible electronic devices (displays, lighting, solar cells), that can be made at low cost and low temperature. These use organic (carbon-containing) molecules or polymers in place of traditional semiconductors, the electrical properties of which can be greatly improved using dopants, which increase (n) or decrease (p) the number of electrons in the material. n-Dopants are generally highly reactive, which complicates their use. The PIs have discovered n-dopants that are unusually stable, yet dope many materials. This program will enable an improved understanding and control of these dopants, related dopants, and their reactivity, and may lead to more efficient devices. Students will be trained in organic electronic materials, and, more generally, in investigating scientific problems, and case-studies will be used in the PIs' lectures. The PIs will educate and train women and underrepresented minorities by: hosting summer students and encouraging their application to graduate school, recruiting via seminars at HBCUs and other minority-serving institutions, and attending workshops and conferences with significant minority participation. The PIs' work with a NSF PREM at New Mexico Highlands University, a minority-serving institution, will be supported; students there will determine the structures of new dopants, and the PIs will give lectures linking chemistry and applications.