Highly Conductive Covalent-Organic Framework Films

Single-Atom Catalysts on Covalent Organic Frameworks for Energy Applications

Single-atom catalysts (SACs) have been investigated and applied to energy conversion devices. However, issues of metal agglomeration, low metal loading, and substrate stability have hindered realization of the SACs' full potential. Recently, covalent organic framework (COF)-based SACs have emerged as promising materials to enable highly efficient catalytic reactions. Here, we summarize the representative COF-based SACs and their wide application in clean energy devices and conversion reactions, such as hydrogen evolution reaction, carbon dioxide reduction reaction, nitrogen reduction reaction, oxygen reduction reaction, and oxygen evolution reaction. Based on their catalysis conditions, these reactions are categorized into photocatalyzed and electrocatalyzed reactions. We also summarize their design strategies, including heteroatom inclusion, donor-acceptor pairs, pore engineering, interface engineering, etc. Although COF-based SACs are promising, more efforts, such as linkage engineering, functional groups, ionization, multifunctional sites for cocatalyzed systems, etc., could improve them to be the ideal SAC materials. At the end, we provide our perspectives on where the field will proceed in the next 5 years.

Two-Dimensional Conjugated Polymers: a New Choice For Organic Thin-Film Transistors

Organic thin-film transistors (OTFTs) as a vital component among transistors have shown great potential in smart sensing, flexible displays, and bionics due to their flexibility, biocompatibility and customizable chemical structures. Even though linear conjugated polymer semiconductors are common for constructing channel materials of OTFTs, advanced materials with high charge carrier mobility, tunable band structure, robust stability, and clear structure-property relationship are indispensable for propelling the evolution of OTFTs. Two-dimensional conjugated polymers (2DCPs), featured with conjugated lattice, tailorable skeletons, and functional porous structures, match aforementioned criteria closely. In this review, we firstly introduce the synthesis of 2DCP thin films, focusing on their characteristics compatible with the channels of OTFTs. Subsequently, the physics and operating mechanisms of OTFTs and the applications of 2DCPs in OTFTs are summarized in detail. Finally, the outlook and perspective in the field of OTFTs using 2DCPs are provided as well.