Porphyrin-Graphene Nanoribbon (PGNR) Conjugates: Solution Syntheses and Properties

石墨烯纳米带(GNRs)由于其高的载流子迁移率和可调的带隙，近年来引起了人们的极大兴趣，使其具有作为碳基半导体的潜力。可控地引入结构缺陷，如非六角环和杂原子，代表了一种有用的策略来调节它们的光电性能。在所有的构建块中，卟啉是同时包含这两个因素的理想候选者。将卟啉与GNR结合在一起可以创造出“超级材料”，这种材料可以从各自的优点中受益。申请人在纳米石墨烯合成方面有五年多的工作经验，在他的博士学位期间开发了一种有效的方法来融合石墨烯分子和卟啉。在这项提案中，申请人将应用先前的方法来合成纵向延伸的卟啉熔融石墨烯纳米带(PGNRs)，并使用跨学科的方法研究其光电性能。具体地说，将设计和合成两种新型的结构复杂的PGNRs：一种是在9原子宽的GNR的主干中嵌入卟啉部分，另一种是将卟啉单元融合到人字形GNR的锯齿形边缘。本项目将解决三个主要问题：1)如何合成具有原子精确结构的PGNRs？由于GNR的准确结构对其电子性质和器件性能至关重要，因此对其化学结构进行原子精确控制至关重要。在这里，将采用溶液合成法，包括合理设计和合成单体嵌段，并采用高效的聚合方法；2)PGNR的性质及其相对于所有碳基GNR的优势是什么？为了回答这个问题，我们将合成正常的9-AgNRs/人字形GNRs和PGNRs。我们将同时比较和研究它们的光电性质和电荷迁移率特性，这将反映出卟啉掺杂的真实效果；3)这些新的PGNRs可以用于什么？这两种PGNR都是高度共轭的，应该具有低能隙和高电荷迁移率。因此，他们将尝试制作单分子场效应晶体管器件。另一方面，卟啉核可以与磁性离子配位，这将使其在制造存储器件和自旋电子器件方面具有广阔的应用前景。这一项目的结果不仅将拓宽我们对GNRs基本性质的理解，而且也为它们未来在分子器件中的应用铺平了道路。

Graphene nanoribbons (GNRs) have attracted tremendous interest in recent years for their high charge carrier mobility and adjustable bandgap, making them potential to be used as carbon-based semiconductors. Controllable introduction of structural defects, such as non-hexagonal rings and heteroatoms, represents a useful strategy to tune their optoelectronic properties. Among all building blocks, porphyrin is an ideal candidate containing both of these two factors. Combining porphyrin with GNR holds great promise to create “super material”, which could benefit from advantages of each component. The applicant has over five years’ working experience in nanographene synthesis and developed one efficient method to fuse graphene molecules with porphyrin during his PhD. In this proposal, the applicant will apply the previous method to synthesize longitudinal extended porphyrin-fused graphene nanoribbons (PGNRs) and investigate their optoelectronic properties using interdisciplinary methodology. Specifically, two new types of structurally complex PGNRs will be designed and synthesized: one has porphyrin moieties embedded in the backbone of 9-atom wide GNR and the other has porphyrin units fused to the zigzag edges of chevron type GNR. Three main questions will be addressed in the current project: 1) How to synthesize PGNRs with atomically precise structures? As the exact structures of GNRs are crucial for their electronic properties and performances in devices, it’s vital to hold atomically precise control over their chemical structures. Here, a solution synthesis method will be applied, which involves rational design and synthesis of monomer building blocks and applying efficient polymerization method; 2) What are the properties of PGNRs and their advantages over their all carbon-based GNR counterparts? To answer this question, we will synthesize both normal 9-AGNRs/Chevron GNRs and PGNRs. Their optoelectronic and charge mobility properties will be compared and investigated in parallel, which will reflect the real effect of porphyrin doping; 3) What could these new PGNRs be used for? Both of these two PGNRs are highly conjugated and should have low energy gap and high charge mobility. So, they will be tried to fabricate single-molecule field-effect transistor devices. On the other hand, the porphyrin core could be coordinated with magnetic ions, which will make them promising for fabricating memory devices and spintronic devices. The results from this project will not only broaden our understanding of fundamental properties of GNRs, but also pave the way for their future applications in molecular devices.