We have successfully synthesized an ultraflat biphenylene carbon sheet consisting of sp2-hybridized carbon atoms forming four-, six-, and eight-membered rings through an on-surface interpolymer dehydrofluorination (HF-zipping) reaction. Scanning tunneling spectroscopy revealed that this carbon allotrope is metallic. This work is published in Science (2021, 372, 852).
We managed to fabricate 2D monolayer Cu-dicyanoanthracene(DCA) metal-organic frameworks (MOF) with long-range order on an epitaxial graphene surface. The ordered DCA3Cu2 network shows a structure combining a honeycomb lattice of Cu atoms with a kagome lattice of DCA molecules and is predicted to be a 2D topological insulator. We confirm that a kagome band structure is formed in the 2D MOF near the Fermi level. In addition, we found that multiple molecular charge states can be generated and modified through the tip-induced local electric fields. This work is published in Advanced Functional Materials (2021, 31, 2100519).
We further extend the synthesis and electronic tunability of 2D MOFs beyond the electronically less relevant metal and semiconducting surfaces to superconducting substrates. Monolayer 2D Cu-DCA MOF has been well-grown on a 2D van der Waals NbSe2 superconducting substrate. This work allows us to follow the formation of the kagome band structure of the 2D MOF from the Star of David-shaped building blocks. This work is published in ACS Nano (2021, 15, 11, 17813).
These works attracted widespread attention within and even beyond the academic community. Relevant achievements have been reported by many academic media and cited in many important review articles and academic monographs.
