Synthesis of 2D Covalent Organic Frameworks at the Solid–Vapor Interface

Abstract

2D covalent organic frameworks (COFs), featuring layered porous structures with covalently bonded building blocks, have attracted great attentions due to their designable and tunable structures and functions and have shown potential applications in many fields. On-surface synthesis is a promising strategy to prepare 2D COFs with a few layers or even single layer in a bottom-up manner. On one hand, surface possesses template effect on the growth of COFs and benefits the uniformity of the molecular materials. On the other hand, 2D COFs grown on surfaces avoid tedious transfer of 2D COFs and are convenient for further integration and application. In this article, we review the bottom-up on-surface synthesis of 2D COFs. The main contents include a thermodynamics equilibrium control synthesis approach and a self-limiting growth control synthesis approach at the solid/vapor interface which improve the quality of 2D COFs; structural diversity of 2D COFs at the solid–vapor interface; fabrication of functional 2D COFs; and investigation of the electronic property of 2D COF films.