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Precision Graphene Nanoribbon Heterojunctions by Chain-Growth Polymerization |
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| Authors: | Jin-Jiang Zhang Kun Liu Yao Xiao Xiuling Yu Li Huang Hong-Jun Gao Ji Ma Xinliang Feng |
| Institution: | 1. Max Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle, Germany;2. Center for Advancing Electronics Dresden (cfaed) & Faculty of Chemistry and Food Chemistry, Technische Universität Dresden, Mommsenstrasse 4, 01062 Dresden, Germany
These authors contributed equally to this work.;3. Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, 100190 Beijing, China School of Physical Sciences, University of Chinese Academy of Sciences, 100190 Beijing, China These authors contributed equally to this work.;4. Center for Advancing Electronics Dresden (cfaed) & Faculty of Chemistry and Food Chemistry, Technische Universität Dresden, Mommsenstrasse 4, 01062 Dresden, Germany;5. Beijing National Center for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, 100190 Beijing, China School of Physical Sciences, University of Chinese Academy of Sciences, 100190 Beijing, China |
| Abstract: | Graphene nanoribbons (GNRs) are considered promising candidates for next-generation nanoelectronics. In particular, GNR heterojunctions have received considerable attention due to their exotic topological electronic phases at the heterointerface. However, strategies for their precision synthesis remain at a nascent stage. Here, we report a novel chain-growth polymerization strategy that allows for constructing GNR heterojunction with N=9 armchair and chevron GNRs segments ( 9-AGNR/cGNR ). The synthesis involves a controlled Suzuki–Miyaura catalyst-transfer polymerization (SCTP) between 2-(6′-bromo-4,4′′-ditetradecyl-1,1′:2′,1′′-terphenyl]-3′-yl) boronic ester ( M1 ) and 2-(7-bromo-9,12-diphenyl-10,11-bis(4-tetradecylphenyl)-triphenylene-2-yl) boronic ester ( M2 ), followed by the Scholl reaction of the obtained block copolymer ( poly-M1/M2 ) with controlled Mn (18 kDa) and narrow ? (1.45). NMR and SEC analysis of poly-M1/M2 confirm the successful block copolymerization. The solution-mediated cyclodehydrogenation of poly-M1/M2 toward 9-AGNR/cGNR is unambiguously validated by FT-IR, Raman, and UV/Vis spectroscopies. Moreover, we also demonstrate the on-surface formation of pristine 9-AGNR/cGNR from the unsubstituted copolymer precursor, which is unambiguously characterized by scanning tunneling microscopy (STM). |
| Keywords: | Block Copolymer Chain-Growth Polymerization Graphene Nanoribbons Heterojunctions Precision Synthesis |