Thiophene is a monoheterocyclic compound. The carbon atoms and sulfur atoms on the thiophene ring form a planar σ bond connected to each other by sp2 hybrid orbitals. At the same time, each carbon atom and heteroatom of the thiophene ring has a parallel p orbital, one p electron in the p orbital on the carbon atom and two p electrons in the p orbital on the sulfur atom form a closed ring of 6π electron conjugation system. The five-membered ring structure of thiophene conforms to Huckel's 4n+2 rule. This makes it have a moderate energy gap and broad spectral response, good environmental stability and thermal stability, and can prepare semiconductor materials with excellent performance. In addition, thiophene derivatives are π-electron-rich heterocyclic compounds, which can be used as excellent optoelectronic material building blocks and electron donor units, and are widely used in the fields of organic solar cells, organic light-emitting diodes, and organic field effect transistors.
Figure 1. Chemical structures of thiophene
- Organic solar cells: Thiophenes have the advantages of moderate energy gap, wide spectral response, good environmental stability and thermal stability. The photosensitive material molecules prepared from thiophene derivatives can efficiently convert the energy of absorbed sunlight into electrical energy, which greatly improves the power generation efficiency of organic solar cells.
- Organic Light Emitting Diodes: Thiophene derivatives can be used as light-emitting materials or transport materials in the field of organic light-emitting diodes because of their electron transport, luminescence and hole transport properties.
- Organic Field Effect Transistor: Thiophene ring is an electron-rich group, and its introduction into semiconductor materials as a functional group can increase electronic coupling, reduce recombination energy, improve intermolecular force, and reduce HOMO (highest occupied molecular orbital) energy level. Combining thiophene with fused ring compounds can improve the stability and mobility of semiconductor materials, and is widely used as a transport material in the field of organic field effect transistor devices.
- Alexandra Baumann, Hammad Cheema, Md Abdus Sabuj, Louis E. McNamara, Yanbing Zhang, Adithya Peddapuram, Suong T. Nguyen, Davita L. Watkins, Nathan I. Hammer, Neeraj Rai, Jared H. Delcamp. Iodine binding with thiophene and furan based dyes for DSCs [J]. Phys. Chem. Chem. Phys., 2018,20, 17859-17870.