Chemistry Approach towards Graphene Nanoribbons with Defined Shape and Edge Structures

石墨烯作为二维碳原子单层近年来受到了极大的关注，然而，仍然缺乏在绝缘表面上制备石墨烯片和具有可再现的限定形状和边缘结构的石墨烯纳米带以获得定制的半导体性质的方法。在目前的优先计划中，我们将从化学的角度特别解决这两个问题。对于在表面上生产石墨烯的自下而上的合成方法，我们将把我们在基于溶液的化学中的丰富经验用于生产定义明确的巨型多环芳烃（PAH），以满足表面化学的要求。我们提出了一种化学路线，这是基于分子内环脱氢（“石墨化”）的定义明确的树枝状（3D）聚亚苯基前体在溶液中和表面上。特别是对于石墨烯纳米带的生产，这种方法在其（i）尺寸和形状控制（ii）结构完美性和（iii）可加工性（溶液，熔体，甚至气相）方面与石墨烯形成的其他物理和化学方法形成鲜明对比。这种自下而上的方法可以通过表面上纳米石墨烯分子的简单热处理进一步建立与石墨烯的联系。除此之外，化学方法允许在两个带端部处附接具有高金属亲和力的锚基团，以使得原则上能够在电极之间自对准。如果这一概念得以确立，石墨烯纳米带在电子器件和材料科学中的广泛应用将成为可能。

Graphene as a two-dimensional atomic carbon monolayer has received tremendous attention in recent years, however, there is still a lack of methods to produce graphene sheets on insulating surfaces and graphene nanoribbons with reproducible defined shape and edge structures to obtain tailor made semiconductor properties. Within the present priority program, we are going to address especially these two issues from the chemical point of view. For the bottom-up synthetic approach towards graphene production on surfaces we will transfer our huge experience in solution based chemistry for the production of well defined giant polycyclic aromatic hydrocarbons (PAHs) into the requirements for surface chemistry. We propose a chemical route which is based upon the intramolecular cyclodehydrogenation (“graphitization”) of well-defined dendritic (3D) polyphenylene precursors in solution and on the surfaces. Especially for the production of graphene nanoribbons this approach is in stark contrast to other physical and chemical methods of graphene formation in terms of its (i) size and shape control (ii) structural perfection and (iii) processability (solution, melt, even gas phase). This bottom-up approach can further establish the link to graphene through the simple thermolysis of nanographene molecules on the surfaces. Beyond this, the chemical approach allows to attach anchor groups with high metal affinity at the both ribbon ends to enable self aligning between electrodes in principle. If this concept can be established, wide applications of graphene nanoribbons in electronic devices and material sciences should be possible in future.