工业染料的大规模生产和广泛应用给地球生态带来了相当大的影响, 对水环境污染非常严重, 而传统色谱和光谱工具难以检测到微弱的光谱和化学信息, 因此开发便携快速的检测技术至关重要。 表面增强拉曼光谱（SERS）是一种与纳米技术相结合的新型分析技术, 可以实现单分子量级化学物质的检测, 但潜力容易受到SERS 基底的增强能力、 稳定性等普适性问题限制。 研究提出了一种简单而通用的策略, 制备了一种基于疏水性有机半导体双(二氰基亚甲基)-封端-二噻吩并［2,3-d; 2’,3’-d］苯并［2,1-b; 3,4-b’］-二噻吩（4CN-DTmBDT）薄膜为衬底的新型SERS复合基底。 首先通过旋涂法制备有机半导体衬底, 该π共轭有机半导体具有分子结构可控、 生物相容性、 光电特性可微调、 成膜形态参数可控等优势, 衬底表面具有疏水性使纳米银粒子（AgNPs）在其表面形成紧密咖啡环, 制备有机半导体-纳米银SERS复合基底, 探究基底拉曼信号的增强效果。 同时提出了一种该有机半导体与纳米银粒子的协同增强机制, 并对增强能力与增强机理进行了相关研究。 结果表明, 紧密咖啡环的形成减小了银纳米颗粒之间的空间, 检测时通过浓缩分析物, 从而增强了热点效应。 对以有机染料为探针分子罗丹明6G（R6G）的检测限低至1×10-8 mol·L-1, SERS增强因子（EF）达1.30×106, 对于疏水性更优异的PDMS与纳米银粒子复合基底检测限为1×10-5 mol·L-1, 说明单独的纳米银粒子对R6G探针信号增强能力有限, 同时证明研究采用的有机半导体与银纳米粒子之间通过协同效应进一步显著提升基底拉曼信号, 而且灵敏度高、 重复性好。 该SERS复合基底对1×10-4和1×10-8 mol·L-1 R6G染料检测的相对标准偏差（RSD）分别为8.3%和4.7%。 实验表明该有机半导体-纳米银复合基底在废水中染料痕量分析领域具有良好的应用潜力。

Large-scale production and wide application of industrial dyes have considerably impacted the Earth’s ecology. Water pollution is very serious. Traditional chromatographic and spectral tools cannot detect weak spectral and chemical information. Therefore, the development of portable and rapid detection technology is essential. Surface-enhanced Raman spectroscopy (SERS) is a new analytical technique combined with nanotechnology, which can realize the detection of single molecular weight chemical substances. However, the potential is easily limited by the universality of SERS substrate enhancement ability and stability. In this study, a simple and general strategy was proposed to prepare a hydrophobic organic semiconductor bis (dicyanomethylene)-end-capped-dithieno ［2,3-d; 2’,3’-d］ benzo ［2,1-b; 3,4-b’］-dithiophene (4CN-DTmBDT) film is a new SERS substrate. Firstly, the organic semiconductor substrate was prepared by the spin-coating method. The π-conjugated organic semiconductor has the advantages of controllable molecular structure, biocompatibility, fine-tuning of photoelectric properties and controllable film-forming morphological parameters. The substrate surface has hydrophobicity, which makes silver nanoparticles (AgNPs) form a tight coffee ring on its surface. The organic semiconductor-nano silver SERS composite substrate was prepared to explore the enhancement effect of the Raman signal of the substrate. This study proposed a possible synergistic enhancement mechanism between the organic semiconductor and silver nanoparticles, and the enhancement ability and mechanism were studied. The results showed that the formation of tight coffee rings reduced the space between silver nanoparticles, and the hot spot effect was enhanced by concentrating the analyte. The detection limit of rhodamine 6G (R6G) with organic dye as the probe molecule was as low as 1×10-8 mol·L-1, and the SERS enhancement factor (EF) was as high as 1.30×106, while the detection limit of PDMS and silver nanoparticles composite substrate with better hydrophobicity was 1×10-5 mol·L-1. At the same time, it was proved that the substrate Raman signal was further enhanced by the synergistic effect between the organic semiconductor and silver nanoparticles in this study, the sensitivity was high, and the repeatability was good. The relative standard deviations (RSD) for detecting 1×10-4 and 1×10-8 mol·L-1 R6G dyes were 8.3% and 4.7%, respectively. Experiments show that the organic semiconductor-nano silver composite substrate has good application potential in trace analysis of dyes in wastewater.