Supramolecular design of pi-electron functional materials

设计和合成新的pi-电子功能材料可以回答基本的物理化学问题，并在从颜料和荧光标签到半导体设备和电化学能量存储介质的广泛应用中发挥作用。我们目前对这类材料的光电性质的了解在单分子水平上是非常先进的，但在分子之间以及分子与界面之间的相互作用非常重要的情况下，我们的理解相当有限。我们的目标是了解有机物质的电子性质是如何在超分子水平上产生和控制的，并利用这种理解来创造新型半导体材料，其中电子导电性是可编程分子自组装的结果。*这项发现助学金将通过以下4个短期项目/目标，继续让5名研究生和w名本科生参与这一目标的研究。我们将：*1)发展新的动态共价化学，适用于在热力学平衡下有序的PI共轭聚合物和共价有机骨架(COF)的自组装。我们的第一个目标是环酮的Aldol环化反应，得到具有偶极-偶极稳定的刚性共轭体系。*2)开发在几个方向上提供有效电子通信的全共轭构建块(无“交叉共轭”)。这将通过使用(I)六位和(Ii)稳定的pi-自由基“节点”来实现，它们将被用作高共轭COF的单体和星形分子材料的核心。*3)通过互补氢键获得对有机半导体的电子性质的控制。P-和n型半导体的共组装和氢键引起的电子极化将导致强烈的带隙调制(导致本征半导体)，并可能导致传导通道可以通过与氢键互补对(包括生物分子)的相互作用而开启。*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。这将对目前的有机场效应晶体管(FET)领域产生立竿见影的影响，是自组装电子器件未来发展的关键一步。*这项工作的科学影响将是：(A)有机化学和固态物理界面的新知识，将有助于推动当前有机电子领域的长远愿景；(B)将推动当前器件技术(FET、太阳能电池)的新型电子功能材料，能够实现新的应用，并将促进与材料物理和生物化学小组的合作。

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.