Supramolecular design of pi-electron functional materials

新型π电子功能材料的设计和合成可以回答基本的物理化学问题，并在从颜料和荧光标记到半导体器件和电化学储能介质的广泛应用中发挥促进作用。我们目前对这种材料的光电性质的理解在单分子水平上非常先进，但在分子相互作用和与界面的相互作用很重要的情况下却相当有限。我们的目标是了解有机物质的电子性质如何产生并在超分子水平上进行控制，并利用这种理解来创造新型的半导体材料，其中电子导电性由于可编程分子自组装而产生。这项发现补助金将持续涉及5名研究生和w名本科生，通过以下4个短期项目/目标实现这一目标。我们将：*1）开发新的动态共价化学，适用于热力学平衡下有序π共轭聚合物和共价有机框架（COF）的自组装。我们的第一个目标是环酮的羟醛环化，导致具有偶极-偶极稳定性的刚性共轭体系。2)开发全共轭构建模块，在几个方向上提供有效的电子通信（没有“交叉共轭”）。这将通过使用（i）六配位的和（ii）稳定的π-自由基“节点”来实现，其将用作高度共辄的COF的单体和用作星形分子材料的核。3)通过互补氢键控制有机半导体的电子性质。p型和n型半导体的共组装以及由于H键导致的电子极化将导致强的带隙调制（产生本征半导体），并且可以导致可以通过与H键互补对（包括生物分子）的相互作用而打开的导电通道。4)了解外部因素（分子或晶体结构以外）在控制有机半导体电荷传输中的作用。这将对当前的有机场效应晶体管（FET）领域产生直接影响，也是未来自组装电子器件发展的关键一步。这项工作的科学影响将是（a）有机化学和固态物理学界面的新知识，这将有助于沿着我们的长期愿景搅动当前的有机电子学领域;（B）新型电子功能材料，这将推进当前的器件技术（FET，太阳能电池），可以实现新的应用，并将促进与材料物理学和生物化学团体的合作。

Design and synthesis of new pi-electron functional materials allows answering fundamental physical chemistry questions, and play an enabling role in a wide spectrum of applications from pigments and fluorescent labels, to semiconducting devices and electrochemical energy storage media. Our current understanding of optoelectronic properties of such materials is very advanced at the level of single molecules, but is rather limited in situations when the interaction of the molecules with each other and with interfaces are important. Our goal is to understand how electronic properties of organic matter arise and can be controlled at supramolecular level, and use this understanding to create novel types of semiconducting materials where an electronic conductivity arises as a result of programmable molecular self-assembly.***This discovery grant will continuously involve 5 graduate students and w undergraduates in research towards this goal through the following short-term 4 projects/objectives. We will:***1) Develop novel dynamic covalent chemistry suitable for self-assembly of ordered pi-conjugated polymers and covalent organic frameworks (COFs) under thermodynamic equilibrium. Our first target is aldol cyclization of cyclic ketones leading to rigid conjugated systems with dipole-dipole stabilization.***2) Develop omniconjugated building blocks that provide efficient electronic communication in several direction (no “cross-conjugation”). This will be accomplished by the use of (i) sexitopic and (ii) stable pi-radicals “nodes”, which will used as monomers for highly conjugated COFs and as cores for star-shaped molecular materials.***3) Gaining control of electronic properties in organic semiconductors via complementary hydrogen bonding. Coassembly of p- and n-type semiconductors and electronic polarization due to H-bonding will lead to strong band-gap modulation (giving rise to intrinsic semiconductors) and can lead to conducting channels that can be turned-on by interaction with H-bonding complementary pairs (including biomolecules).***4) Understanding the role of external factors (other than molecular or crystal structure) in controlling the charge transport through organic semiconductors. This will have an immediate impact on the current field of organic field effect transistors (FET), and is a critical step for the future development of self-assembled electronic devices.***The scientific impact of this work will be (a) new knowledge at the interface of organic chemistry and solid state physics, that will help stirring the current field of organic electronics along our long term vision and (b) novel electronically functional materials that will advance the current device technologies (FETs, solar cells), can enable novel applications, and will foster collaborations with materials physics and biochemistry groups.