High-Performance Phototransistors Based on PDIF-CN2 Solution-Processed Single Fiber and Multifiber Assembly

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• 作者：Wassima Rekab ; Marc-Antoine Stoeckel ; Mirella El Gemayel ; Marco Gobbi ; Emanuele Orgiu ; Paolo Samorì
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：April 20, 2016
• 年：2016
• 卷：8
• 期：15
• 页码：9829-9838
• 全文大小：563K
• 年卷期：0
• ISSN：1944-8252

文摘

Here we describe the fabrication of organic phototransistors based on either single or multifibers integrated in three-terminal devices. These self-assembled fibers have been produced by solvent-induced precipitation of an air stable and solution-processable perylene di-imide derivative, i.e., PDIF-CN₂. The optoelectronic properties of these devices were compared to devices incorporating more disordered spin-coated PDIF-CN₂ thin-films. The single-fiber devices revealed significantly higher field-effect mobilities, compared to multifiber and thin-films, exceeding 2 cm² V^–1 s^–1. Such an efficient charge transport is the result of strong intermolecular coupling between closely packed PDIF-CN₂ molecules and of a low density of structural defects. The improved crystallinity allows efficient collection of photogenerated Frenkel excitons, which results in the highest reported responsivity (R) for single-fiber PDI-based phototransistors, and photosensitivity (P) exceeding 2 × 10³ AW^–1, and 5 × 10³, respectively. These findings provide unambiguous evidence for the key role played by the high degree of order at the supramolecular level to leverage the material’s properties toward the fabrication of light-sensitive organic field-effect transistors combining a good operational stability, high responsivity and photosensitivity. Our results show also that the air-stability performances are superior in devices where highly crystalline supramolecularly engineered architectures serve as the active layer.