采用柠檬酸三钠还原氯金酸和离子交换法制备金纳米粒子掺杂DNA-CTMA材料, 利用钯催化反应合成9, 9-二乙基-2, 7-二-(4-吡啶)芴荧光染料(DPFP), 将DPFP与DNA-CTMA混合后, 旋凃制备金纳米粒子掺杂的DNA-CTMA-DPFP薄膜样品。通过吸收光谱、荧光光谱和拉曼光谱的测量, 研究了薄膜样品的光学特性和表面增强拉曼散射(SERS)特性。实验结果表明, 薄膜样品在300～360 nm的吸收主要来自DPFP, 在500～700 nm的吸收来自样品中金纳米粒子的局域表面等离子共振; 样品在370, 386, 408 nm处的荧光峰分别对应DPFP的S10-S00、S10-S01和S10-S02能级的电子振动跃迁; 在785 nm激光激发下, 薄膜样品的拉曼散射主要来自DPFP分子, 随着金纳米粒子掺杂比的增大, DPFP分子的拉曼散射峰强度逐渐增强。因此, 金纳米粒子掺杂DNA-CTMA薄膜适合作为多种染料分子的SERS基底。

The gold nanoparticles were prepared by the reduction of gold chloride with sodium citrate in aqueous solution and the gold-nanoparticles-doped DNA-CTMA complexes were prepared by ion-change method, and the 4-(9, 9-diethyl-2-(pyridin-4-yl)-9H-fluoren-7-yl) pyridine (DPFP) was synthesized via a Suzuki coupling reaction. The gold-nanoparticles-doped DNA-CTMA-DPFP film samples were fabricated by spin-coating the mixed butanol solutions of gold-nanoparticles-doped DNA-CTMA complexes and DPFP. The optical spectra properties and surface enhanced Raman scattering (SERS) characteristics of the film samples were characterized by measuring their absorption spectra, fluorescence spectra, and Raman spectra, respectively. The experimental results show that the absorption of film samples in the range of 300～360 nm are derived mainly from the DPFP dye molecule, whereas the absorption ranging from 500 nm to 700 nm come from the local surface plasma resonance (LSPR) of gold nanoparticles, and the fluorescence spectra exhibits well-defined vibronic peaks at 370 nm (S10-S00 transition), 386 nm (S10-S01 transition), with a shoulder near 408 nm (S10-S02 transition). The Raman spectra of DPFP dye molecule in the film samples were excited by a laser with the wavelength 785 nm, and the SERS peak intensities of DPFP molecule gradually increase as the increases of gold nanoparticles doped into the DNA-CTMA complexes. Therefore, the gold-naoparticles-doped DNA-CTMA films are suitable as the SERS substrates of many dye molecules.