Customizable 2D Covalent Organic Frameworks for Optoelectronic Applications

Abstract

2D covalent organic framework (2D-COF), a modular three-dimensional material, is easily influenced by the component module. The assembly of different functionalized modules gives 2D-COF unique performance. The modular structure not only allows for customization but also allows for variety, which gives 2D-COF a wide range of functions. Hence, many building blocks with catalytic, ligand, semiconductor, luminescent, and redox centers are integrated into the COF scaffold. The connection and assembly of such modules determine the nature of the final block material. The intra-layer connections of the modules form a monolayer mesh chemical structure, and the subsequent stacking of the monolayer mesh structure produces the final crystalline porous material-2D-COF. This review describes in detail the potential of COF materials as optoelectronic materials and our understanding of optoelectronic processes, starting from monolayer reticulation chemistry to final 3D stacked structures, thus establishing a new paradigm for the rational design of well-defined novel 2D-COF optoelectronic materials and devices.

In-Depth Photocatalytic Degradation Mechanism of the Extensively Used Dyes Malachite Green, Methylene Blue, Congo Red, and Rhodamine B via Covalent Organic Framework-Based Photocatalysts

“…Two-dimensional COF-based photocatalysts exhibit tremendous photocatalytic capabilities due to their extended sp 2 hybridized orbital construction, which facilitates efficient charge-carrier transport [53]. Importantly, the presence of both electron donors and acceptors within the same COF structure is crucial for stabilizing photoexcited electrons and holes, which are readily available for redox reactions [54]. The band gap energy is an important parameter of any designed photocatalyst.…”

“…Incorporating donor-acceptor moieties into COF-based materials has been validated as an effective strategy for promoting charge separation. In this context, facilitating charge transfer between bridging units and porphyrins efficiently mitigates electron-hole recombination, thereby enhancing photocatalytic activity [53][54][55][56][57][58]. As a result, porphyrin-based COFs emerge as promising photocatalysts, capable of effectively degrading organic dyes and pollutants [138].…”

Peroxymonosulfate enhanced photocatalytic degradation of organic dye by metal-free TpTt-COF under visible light irradiation

“…A covalent organic framework (COF) is an emerging material with a controllable crystal structure formed by stable periodic aromatic units through covalent bonds 27 . Two-dimensional COFs have excellent photocatalytic ability because of their extended Sp 2 hybridized orbit structure, which can promote charge carrier transport 28 . More importantly, the presence of electron donors and acceptors in the same COF is essential for stabilizing the photoexcited electrons and holes readily used for redox reaction to activate PMS.…”

Stranski–Krastanov Growth of Two-Dimensional Covalent Organic Framework Films

“…Covalent organic frameworks (COFs) are a class of crystalline porous polymers with promising prospects in catalysis, , sensing, , separation, , and optoelectronics. , Considering the insolubility and poor processability of COF powders, the preparation of COF films with designable components and structures is a prerequisite for ultimately realizing their potential as functional materials. In recent years, various synthesis strategies such as solvothermal polymerization, interfacial polymerization, and vapor-assisted synthesis have been developed to construct COF films supported on desired substrates or as free-standing films. − However, gaining control over the thickness, morphology, and orientation of COF films, which is highly desirable for their applications in various fields, , remains a critical challenge.…”