Step edge-mediated assembly of periodic arrays of long graphene nanoribbons on Au(111)

Graphene nanoribbons (GNRs) can be fabricated with atomic precision via bottom-up synthesis on metal substrates, but the growth of long GNRs still remains a challenge. We have previously investigated the growth mechanism of GNRs from molecular precursors on Au substrate [1]. Recently, we have observed that the step edges of an Au (111) substrate can enhance GNR growth and yield significantly longer GNRs and periodic GNR arrays on the Au(111) surface [2]. By studying the atomic structures and electronic properties <!-- You studied adsorption energies instead of electronic properties in this paper, correct? -->near step edges by DFT calculations, we have found that the intermediate polyanthryl structures adsorb more strongly along Au step edges due to pi-pi interactions between polyanthryls near the steps, which result in longer and more compact polymer arrays and lead to the synthesis of longer GNRs. Our findings suggest a direction for the manufacturing of longer GNRs for future applications.
[1] Z. Xiao, C. Ma, W. Lu, J. Huang, L. Liang, K. Hong, A.-P. Li, B. G. Sumpter, J. Bernholc, npj Comp. Mat. 5, 91 (2019).
[2] C. Ma, Z. Xiao, W. Lu, J. Huang, K. Hong, J. Bernholc, A.-P. Li, Chem. Commun. 55, 11848-11851 (2019).