Oligothiophene-Bridged Conjugated Covalent Organic Frameworks

Area of Science:

• Materials Science
• Organic Chemistry
• Solid-State Physics

Background:

• Two-dimensional covalent organic frameworks (2D-COFs) are crystalline porous materials with potential in organic electronics.
• Constructing oligothiophene-based COFs, especially laterally conjugated imine-linked ones, has been challenging.
• Tailoring electronic properties of 2D-COFs is crucial for optoelectronic applications.

Purpose of the Study:

• To develop a novel building block design for constructing highly crystalline quaterthiophene-derived 2D-COFs.
• To achieve tunable electronic properties in imine-linked 2D-COFs.
• To investigate the optical response and electronic states within these new COFs.

Main Methods:

• Design and synthesis of a new asymmetric building block based on a quaterthiophene backbone.
• Construction of a series of imine-linked 2D-COFs using the novel building block.
• Optical spectroscopy to study the electronic properties and observe charge transfer states.

Main Results:

• Successful synthesis of highly crystalline quaterthiophene-derived 2D-COFs with tunable electronic properties.
• Observation of a charge transfer state between COF subunits across the imine bond for the first time.
• Demonstration of a general strategy for constructing well-ordered COFs from extended building blocks.

Conclusions:

• The new asymmetric building block design overcomes previous limitations in constructing imine-linked 2D-COFs.
• The developed 2D-COFs show promise for applications in organic electronics and optoelectronics.
• This approach significantly expands the range of molecules applicable for 2D-COF synthesis.