Graphene nanoribbons (GNRs) show favorable electronic and optical properties due to their excellent stability at ambient conditions and are suitable materials for nanoscale electronic devices. 10,10′-Dibromo-9,9′-bianthracene (DBBA) has proven to be a suitable precursor for on-surface synthesis of GNRs because it shows a manifold of temperature-assisted reactions like dehalogenation, debromination, or Ullman-coupling on metal surfaces. We use DBBA to conduct a thorough investigation across a wide temperature range (170–750 K) and to track the formation process of 7-graphene nanoribbons (7-GNRs) on Au(111), Ag(111), and Cu(111) substrates by utilizing X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). The reaction pathways exhibit a strong dependence on the substrate reactivity: on Au(111), the reactions require annealing and 7-GNRs are formed at 560 K; on Ag(111), debromination occurs at 400 K and 7-GNRs are achieved at 695 K; and on Cu(111), the robust chemical interaction at the interface leads to the debromination upon deposition (at 170 K) and the final product is formed at 750 K. Overall, we demonstrate that DBBA serves as a valuable precursor to GNRs, while the metal substrates play a crucial role to effect the growth behavior of organic materials.

中文翻译：

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石墨烯纳米带的表面合成：光电子能谱揭示基材反应性的影响

石墨烯纳米带（GNR）由于其在环境条件下优异的稳定性而表现出良好的电子和光学性能，是纳米电子器件的合适材料。10,10′-二溴-9,9′-联蒽（DBBA）已被证明是表面合成 GNR 的合适前体，因为它在表面上表现出多种温度辅助反应，如脱卤、脱溴或乌尔曼偶联。金属表面。我们使用 DBBA 在较宽的温度范围 (170–750 K) 进行彻底的研究，并跟踪 Au(111)、Ag(111) 和 Cu(111) 上 7-石墨烯纳米带 (7-GNR) 的形成过程）利用X射线光电子能谱（XPS）和紫外光电子能谱（UPS）对基底进行分析。反应途径表现出对底物反应性的强烈依赖性：在 Au(111) 上，反应需要退火，并且在 560 K 时形成 7-GNR；Ag(111) 在 400 K 时发生脱溴，在 695 K 时实现 7-GNR；在 Cu(111) 上，界面处强大的化学相互作用导致沉积时脱溴（在 170 K 下），最终产物在 750 K 下形成。总的来说，我们证明 DBBA 可以作为 GNR 的有价值的前体，而金属基底对影响有机材料的生长行为起着至关重要的作用。