Synthesis and Characterization of Benzobisoxazole-based Conjugated Polymers for Organic Photodetectors

Abstract

Benzo[1,2-d:4,5-d’]bis(oxazole) (BBO) is a conjugated building block that can be easily synthesized for the development of organic optoelectronic polymers. Here, the authors synthesized BBO-based polymers, P1 and P2, by coupling BBO with thiophenes for use in organic photodetectors (OPDs). The optical characteristics of P1 and P2 make them suitable for OPDs, as they selectively absorb the green light with a narrow bandwidth in the range of 500–600 nm. The OPD devices were fabricated by making a bulk heterojunction active layer between the synthesized polymers and a nonfullerene acceptor, IDIC. P1-based devices showed slightly higher responsivity (R) of 0.169 A/W than 0.112 A/W of P2-based devices. However, the P2-based device was higher than D* value of the P1-based under 100 μW/cm2, which was due to the influence of excessive thiophene units that had low dark current density.