Progress in synthesis of highly crystalline covalent organic frameworks and their crystallinity enhancement strategies

Covalent organic frameworks (COFs) have been attracting growing concerns since the first report in 2005. With the well-defined and ordered structures, COFs express big potential in mass transport, storage/separation and energy conversion applications. From the perspective of both theory and application, the construction of crystalline COFs with high quality and variety is highly worth to be devoted to. To give insight into the crystalline process of COFs and deeply understand the factors of COFs crystallization, this review was concentrated on the recent progress in construction of crystalline COFs. Accordingly, the types and crystallization process of COFs were summarized firstly. And then the factors on crystallinity and the measures for improving the crystallinity of COFs were classified and discussed in detail. Finally, the perspectives for the development of COFs in further was given at the end of this review.