π-Conjugated organic semiconductors have been explored in several optoelectronic devices, yet their use in molecular detection as surface-enhanced Raman spectroscopy (SERS)-active platforms is unknown. Herein, we demonstrate that SERS-active, superhydrophobic and ivy-like nanostructured films of a molecular semiconductor, α,ω-diperfluorohexylquaterthiophene (DFH-4T), can be easily fabricated by vapour deposition. DFH-4T films without any additional plasmonic layer exhibit unprecedented Raman signal enhancements up to 3.4 × 10³ for the probe molecule methylene blue. The combination of quantum mechanical computations, comparative experiments with a fluorocarbon-free α,ω-dihexylquaterthiophene (DH-4T), and thin-film microstructural analysis demonstrates the fundamental roles of the π-conjugated core fluorocarbon substitution and the unique DFH-4T film morphology governing the SERS response. Furthermore, Raman signal enhancements up to ~10¹⁰ and sub-zeptomole (<10⁻²¹ mole) analyte detection were accomplished by coating the DFH-4T films with a thin gold layer. Our results offer important guidance for the molecular design of SERS-active organic semiconductors and easily fabricable SERS platforms for ultrasensitive trace analysis.

中文翻译：

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用于表面增强拉曼光谱检测分子的纳米结构有机半导体薄膜

π-共轭有机半导体已在数种光电器件中得到了探索，但它们在分子检测中作为表面增强拉曼光谱（SERS）活性平台的用途尚不清楚。在本文中，我们证明了可以通过气相沉积容易地制备分子半导体的SERS活性，超疏水和常春藤状的纳米结构薄膜α，ω-二全氟己基四噻吩（DFH-4T）。对于探针分子亚甲基蓝，没有任何附加等离子体层的DFH-4T膜表现出前所未有的拉曼信号增强效果，最高可达3.4×10 ³。结合量子力学计算，无氟碳素α，ω的对比实验-二己基四噻吩（DH-4T）和薄膜微结构分析证明了π-共轭核心碳氟化合物取代的基本作用以及控制SERS反应的独特DFH-4T膜形态。此外，拉曼信号增强高达〜10 ¹⁰和子zeptomole（<10 ^-21摩尔）的分析物检测通过用薄金层涂覆DFH-4T膜来实现的。我们的结果为SERS活性有机半导体的分子设计和易于制造的用于超灵敏痕量分析的SERS平台提供了重要指导。