π-Extended perylene diimide double-heterohelicenes as ambipolar organic semiconductors for broadband circularly polarized light detection

Despite great challenges, the development of new molecular structures with multiple and even conflicting characteristics are eagerly pursued for exploring advanced applications. To develop high-performance chiral organic semiconducting molecules, a distorted -system is required for strong coupling with circularly polarized light (CPL), whereas planar pi -stacking systems are necessary for high charge-carrier mobility. To address this dilemma, in this work, we introduce a skeleton merging approach through distortion of a perylene diimide (PDI) core with four fused heteroaromatics to form an ortho-pi -extended PDI double-[7]heterohelicene. PDI double helicene inherits a high dissymmetry factor from the helicene skeleton, and the extended pi -planar system concurrently maintains a high level of charge transport properties. In addition, ortho-pi -extension of the PDI skeleton brings about near-infrared (NIR) light absorption and ambipolar charge transport abilities, endowing the corresponding organic phototransistors with high photoresponsivity of 450 and 120mAW(-1) in p- and n-type modes respectively, along with a high external quantum efficiency (89%) under NIR light irradiations. Remarkably, these multiple characteristics enable high-performance broadband CPL detections up to NIR spectral region with chiral organic semiconductors. In organic semiconducting molecules materials, distorted pi -systems enable strong coupling with circular polarized light while planar pi -stacking systems are necessary for high charge-carrier mobility. Here, the authors address this dilemma by introducing a skeleton merging approach through distortion of a perylene diimide core with four fused heteroaromatics to form a pi -extended double helicene.

Automated summary

In this study, a novel approach of skeleton merging was introduced to address the dilemma between strong coupling with circular polarized light and high charge-carrier mobility in high-performance chiral organic semiconducting molecules. The resulting pi-extended double helicene structure exhibits high dissymmetry factor, extended pi-planar system for charge transport properties, near-infrared light absorption, and ambipolar charge transport abilities, enabling high photoresponsivity and external quantum efficiency in both p- and n-type modes under NIR light irradiation. These characteristics allow for high-performance broadband CPL detections up to the NIR spectral region.