NCAFM2023 Programme Booklet

Monday 1140 - 1200

ON SURFACE SYNTHESIS OF NONPLANAR GRAPHENE NANORIBBONS EMBEDDED WITH PERIODIC DIVACANCIES

Chuanxu Ma 1,* , Ruoting Yin 1 , Zhengya Wang 1 , Jie Meng 1 , Jianing Wang 1 , Zhen-Lin Qiu 2 , Yuan-Zhi Tan 2 , Qunxiang Li 1 , Bing Wang 1* 1 Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China 2 Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, 361005 Xiamen, China Email: cxma85@ustc.edu.cn; bwang@ustc.edu.cn

Periodically embedding structural defects, such as vacancies, nonhexagonal rings, and heteroatoms into the basal hexagonal lattice of graphene provides a predicable way aiming to electronic properties engineering for potential applications. Recent development of on-surface synthesis [1], based on rationally designed molecular precursors, has become a remarkable success in atomically precisely fabricating novel graphene superlattices with periodic structural modulations, as exemplified by nanopores in graphene sheets and graphene nanoribbons (GNRs) [2-4], and heteroatoms of B and N in GNRs [5,6], and also a wide range of interesting carbon allotropes that consist of various nonbenzenoid combinations [7-10]. However, it still remains challenging to synthesize periodic divacancies embedded GNRs. In this talk, I will introduce two different approaches toward this goal. One is the substrate-step assisted synthesis of the eight-carbon-wide armchair GNRs embedded with periodic hydrogenated divacancies [11]. The other is the self-limited embedding of alternating 585-ringed divacancies and metal atoms into graphene nanoribbons with width of seven carbon atoms [12]. We perform high-resolution scanning tunneling microscopy/spectroscopy and non-contact atomic force microscopy joint with first-principles calculations, we in situ monitor the evolution of the distinct structural and electronic properties in the reaction intermediates. We observe distinct nonplanar features and electronic properties of the hydrogenated and 585-ringed divacancies. The reaction mechanisms are further elucidated by our nudged elastic band calculations, which unveil the important roles of the substrate heterogeneities. Our findings open an avenue to introducing periodic impurities of divacancy pores, single metal atoms and nonhexagonal rings in on-surface synthesis, which may provide a novel route for multifunctional graphene nanostructures. [2] P. H. Jacobse et al., J. Am. Chem. Soc. 142, 13507 (2020). [3] R. Pawlak et al., J. Am. Chem. Soc. 142, 12568 (2020). [4] C. Moreno et al., Science 360, 199 (2018). [5] E. C. H. Wen, P. H. Jacobse, J. Jiang, Z. Wang, R. D. McCurdy, S. G. Louie, M. F. Crommie, and F. R. Fischer, J. Am. Chem. Soc. 144, 13696 (2022). [6] S. Kawai, S. Saito, S. Osumi, S. Yamaguchi, A. S. Foster, P. Spijker, and E. Meyer, Nat. Commun. 6, 8098 (2015). [7] Q. Fan et al., Science 372, 852 (2021). [8] B. de la Torre et al., Nat. Commun. 11, 4567 (2020). [9] M. Di Giovannantonio, Q. Chen, J. I. Urgel, P. Ruffieux, C. A. Pignedoli, K. Mullen, A. Narita, and R. Fasel, J. Am. Chem. Soc. 142, 12925 (2020). References [1] H. Wang, H. S. Wang, C. Ma, L. Chen, C. Jiang, C. Chen, X. Xie, A.-P. Li, and X. Wang, Nat. Rev. Phys. 3, 791 (2021).

[10] D.-Y. Li et al., J. Am. Chem. Soc. 143, 12955 (2021). [11] R. Yin et al., J. Am. Chem. Soc. 144, 14798 (2022). [12] Z. Wang et al., J. Am. Chem. Soc., doi:10.1021/jacs.3c00111 (2023).

12