Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany.
Center for Advancing Electronics Dresden (cfaed) and Department of Chemistry and Food Chemistry, Technische Universität Dresden , Mommsenstrasse 4, 01062 Dresden, Germany.
Anal Chem. 2017 Jul 18;89(14):7485-7492. doi: 10.1021/acs.analchem.7b01135. Epub 2017 Jun 28.
We present a mass spectrometric approach to characterize and monitor the intermediates of graphene nanoribbon (GNR) formation by chemical vapor deposition (CVD) on top of Au(111) surfaces. Information regarding the repeating units, lengths, and termini can be obtained directly from the surface sample by a modified matrix-assisted laser desorption/ionization (MALDI) method. The mass spectrometric results reveal ample oxidative side reactions under CVD conditions that can be drastically diminished by the introduction of protective H gas at ambient pressure. Simultaneously, the addition of hydrogen extends the lengths of the oligophenylenes and thus the final GNRs. Moreover, the prematurely formed cyclodehydrogenation products during the oligomer growth can be assigned by the mass spectrometric technique. The obtained mechanistic insights provide valuable information for optimizing and upscaling the bottom-up fabrication of GNRs. Given the important role of GNRs as semiconductors, the mass spectrometric analysis provides a readily available tool to characterize and improve their structural perfection.
我们提出了一种质谱方法，用于通过化学气相沉积（CVD）在 Au(111)表面上表征和监测石墨烯纳米带（GNR）形成的中间体。通过改进的基质辅助激光解吸/电离（MALDI）方法，可以直接从表面样品中获得有关重复单元、长度和末端的信息。质谱结果表明，在 CVD 条件下存在大量的氧化副反应，通过在环境压力下引入保护性 H 气可以大大减少这些副反应。同时，添加氢气可以延长寡聚苯的长度，从而最终得到 GNR。此外，通过质谱技术可以对寡聚物生长过程中过早形成的环脱氢产物进行归属。所获得的机理见解为优化和扩大 GNR 的自下而上制造提供了有价值的信息。鉴于 GNR 作为半导体的重要作用，质谱分析提供了一种现成的工具来表征和改善其结构完整性。
