Optoelectronic Properties and Structural Modification of Conjugated Polymers Based on Benzodithiophene Groups

Organic conjugated materials have shown attractive applications due to their good optoelectronic properties, which enable them solution processing techniques in organic optoelectronic devices. Many conjugated materials have been investigated in polymer solar cells and organic field-effect transistors. Among those conjugated materials, Benzo[1,2-b:4,5-b′]dithiophene (BDT) is one of the most employed fused-ring building groups for the synthesis of conjugated materials. The symmetric and planar conjugated structure, tight and regular stacking of BDT can be expected to exhibit the excellent carrier transfer for optoelectronics. In this review, we summarize the recent progress of BDT-based conjugated polymers in optoelectronic devices. BDT-based conjugated materials are classified into onedimensional (1D) and two-dimensional (2D) BDT-based conjugated polymers. Firstly, we introduce the fundamental information of BDT-based conjugated materials and their application in optoelectronic devices. Secondly, the design and synthesis of alkyl, alkoxy and aryl-substituted BDT-based conjugated polymers are discussed, which enables the construction of one-dimensional and two-dimensional BDTbased conjugated system. In the third part, the structure modification, energy level tuning and morphology control and their influences on optoelectronic properties are discussed in detail to reveal the structure- property relationship. Overall, we hope this review can be a good reference for the molecular design of BDT-based semiconductor materials in optoelectronic devices.