On-surface synthesis of one-type pore single-crystal porous covalent organic frameworks.

Employing a 1,3,5-tris(4-bromophenyl)benzene precursor as a building block, we successfully fabricate large-scale, non-multihole and single-layer pCOFs on the Ag(111) surface in a controllable manner via the on-surface reaction. We reveal that two main factors, the heating rate and growth temperature, have a strong impact on the size and quality of the pCOFs by STM. Furthermore, the band gap of the pCOFs has been further measured to be approximately 3.01 eV.