Abstract
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 π-system is required for strong coupling with circularly polarized light (CPL), whereas planar π-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-π-extended PDI double-[7]heterohelicene. PDI double helicene inherits a high dissymmetry factor from the helicene skeleton, and the extended π-planar system concurrently maintains a high level of charge transport properties. In addition, ortho-π-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 120 mA W−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.
Highlights
Despite great challenges, the development of new molecular structures with multiple and even conflicting characteristics are eagerly pursued for exploring advanced applications
Despite significant distortion in these bay-substituted[29] and ortho-fused[30,31] perylene diimide (PDI) systems, a fast interconversion process between the P- and M-enantiomers prevents the isolation of enantiopure derivatives for further applications
As the activation parameters for conformational chiral systems are influenced by the size of the substituents, we speculated that annulation of four indole/benzothiophene rings to perylene skeleton with heteroatom at ortho-position should lead to conformationally stable double-[7]heterohelicene 3a (X = NH) and 3b (X = S) with overlapping terminal aromatic rings (Fig. 1a)
Summary
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 π-system is required for strong coupling with circularly polarized light (CPL), whereas planar π-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-π-extended PDI double-[7]heterohelicene. Ortho-π-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 120 mA W−1 in p- and n-type modes respectively, along with a high external quantum efficiency (89%) under NIR light irradiations These multiple characteristics enable high-performance broadband CPL detections up to NIR spectral region with chiral organic semiconductors. This broadband CPL detection could provide unprecedented opportunities in optoelectronics, by introducing a new functionality to various prospective applications, including motion detection, remote sensing, health monitoring, photoplethysmogram sensor, spectrometric analysis, and night vision
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