Narita Akimitsu, Chen Zongping, Chen Qiang, Müllen Klaus
Max Planck Institute for Polymer Research , Ackermannweg 10 , D-55128 Mainz , Germany . Email:
Institute of Physical Chemistry , Johannes Gutenberg-University Mainz , Duesbergweg 10-14 , D-55128 Mainz , Germany.
Chem Sci. 2019 Jan 2;10(4):964-975. doi: 10.1039/c8sc03780a. eCollection 2019 Jan 28.
Graphene nanoribbons (GNRs) are quasi-one-dimensional subunits of graphene and have open bandgaps in contrast to the zero-bandgap graphene. The high potential of GNRs as a new family of carbon-based semiconductors, for nanoelectronic and optoelectronic applications, has boosted the research attempts towards fabrication of GNRs. The predominant top-down methods such as lithographical patterning of graphene and unzipping of carbon nanotubes cannot prevent defect formation. In contrast, bottom-up chemical synthesis, starting from tailor-made molecular precursors, can achieve atomically precise GNRs. In this account, we summarize our recent research progress in the bottom-up synthesis of GNRs through three different methods, namely (1) in solution, (2) on-surface under ultrahigh vacuum (UHV) conditions, and (3) on-surface through chemical vapour deposition (CVD). The solution synthesis allows fabrication of long (>600 nm) and liquid-phase-processable GNRs that can also be functionalized at the edges. On the other hand, the on-surface synthesis under UHV enables formation of zigzag GNRs and visualization of their chemical structures by atomic-resolution scanning probe microscopy. While the on-surface synthesis under UHV is typically costly and has limited scalability, the industrially viable CVD method can allow lower-cost production of large GNR films. We compare the three methods in terms of the affordable GNR structures and the resulting control of their electronic and optical properties together with post-processing for device integration. Further, we provide our views on future perspectives in the field of bottom-up GNRs.
石墨烯纳米带（GNRs）是石墨烯的准一维亚基，与零带隙的石墨烯不同，它具有开放带隙。GNRs作为一类新型碳基半导体，在纳米电子和光电子应用方面具有巨大潜力，这推动了人们对其制备的研究尝试。诸如石墨烯的光刻图案化和碳纳米管的解链等主要的自上而下方法无法避免缺陷的形成。相比之下，从定制的分子前驱体开始的自下而上的化学合成能够实现原子级精确的GNRs。在本综述中，我们总结了我们最近通过三种不同方法自下而上合成GNRs的研究进展，即（1）在溶液中，（2）在超高真空（UHV）条件下的表面上，以及（3）通过化学气相沉积（CVD）在表面上。溶液合成能够制备长（>600 nm）且可进行液相加工的GNRs，其边缘也可以进行功能化。另一方面，在超高真空下的表面合成能够形成锯齿形GNRs，并通过原子分辨率扫描探针显微镜观察其化学结构。虽然超高真空下的表面合成通常成本高昂且可扩展性有限，但工业上可行的CVD方法可以实现低成本生产大面积的GNR薄膜。我们从可实现的GNR结构、对其电子和光学性质的控制以及用于器件集成的后处理等方面对这三种方法进行了比较。此外，我们还对自下而上合成GNRs领域的未来前景发表了看法。
