Structural Design and Applications of Stereoregular Fused Thiophenes and Their Oligomers and Polymers

Abstract

Stereoregular fused thiophenes (SFTs: especially thieno[3,2-b]thiophene (TT) and dithieo[3,2-b:2′,3′-d]thiophene (DTT)), as stable conjugated structures deriving from thiophene ring enlargement, possess outstanding properties and special configuration, such as the superior carrier transfer efficiency and a high degree backbone of planarity. In comparison to stand-alone SFTs structures, oligomers and polymers containing different heteroaromatic units have been much widely researched and used in many fields. In decade, several important reviews have summarized the broad field of fused thiophenes including SFTs, and their synthesis and optoelectronic applications. Here, we critically present the structure–performance relationships and application of oligomers and polymers containing SFTs (exhibiting thiophene ring number from 2 to 7) units. First, the basic structures and properties of SFTs are briefly stated. Then, oligomers classified by extra conjugated heterocyclic attachments are carefully discussed, focusing on the structure–performance relationships for their optoelectronic applications including organic photovoltaic cells and organic field-effect transistors. Moreover, such relationships in polymers have been applied in much wider fields such as organic light-emitting diodes, electrochromic devices, thermoelectric devices, and supercapacitors are discussed. Finally, a summary and prospect are given. Through this review, instruction for molecular design and novel ideas for the future development of SFTs-contained are provided.

Graphical Abstract

Keywords:

• Organic electronics
• aromatic heterocycles
• fused thiophenes
• oligomers
• conjugated polymers

Additional information

Funding

This work was supported by the National Natural Science Foundation of China under Grant 51603095 and 51863009; the scholarship from China Scholarship Council under Grant 201808360327; Natural Science Foundation of Jiangxi Province under Grant 20192BAB216012; Scientific Fund of Jiangxi Science & Technology Normal University under Grant 2016QNBJRC003; Jiangxi Educational Committee for a Postgraduate Innovation Program Grant under Grant YC2018-X29.