光照法在玻璃基底上原位生长金纳米结构及其光谱性质

 以硅烷化后吸附粒径小于10 nm的金种子的玻璃片为基底，聚乙烯吡咯烷酮为还原剂，在荧光灯照射条件下还原氯金酸，制备出表面具有金纳米粒子聚集结构的基底。用原子力显微镜、扫描电镜、X射线衍射、吸收和荧光光谱研究了基底的性质。结果表明：随着光照时间增加至20 h，金种子长大为平均粒径140 nm的不规则状多晶粒子，且出现双层粒子堆叠。基底的吸收光谱上出现了由金粒子的表面等离子体激元偶极子耦合引发的强烈吸收峰，随着粒子粒径增大，耦合峰在600~800 nm波段内连续红移升高，表明耦合程度不断增强。在223 nm紫外光的激发下，基底的荧光光谱上在405 nm处出现发射峰，是由金粒子表面激发电子和空穴的复合辐射造成的，发光强度随着基底上粒子平均尺度增加而减弱。

In-situ growth of gold nanostructure on glass substrates by light irradiation and their spectral properties

Substrates with gold nanoparticles aggregates adsorbed on their surfaces were prepared after irradiation of silanized glass substrates attached with gold seeds smaller than 10 nm by a fluorescent lamp,with poly(vinylpyrrolidone) as reductant and HAuCl4 as precursor.The substrates were characterized by atomic force microscopy,scanning electron microscopy,X-ray diffraction,absorption and fluorescence spectroscopy.The results showed that the multi-crystalline gold nanoparticles which finally grew up to 140 nm after 20-hour irradiation took on irregular shape,and some of them stacked to form bilayer structure.A new broad band appeared in the absorption spectra of the substrates due to the interparticle dipole-dipole coupling of surface plasmon resonance response of the gold particles,which redshifted within 600~800 nm as the particles grew up,indicating the intensification of the coupling.The substrates had an emission band centered at 405 nm in their fluorescence spectra under excitation at 223 nm,which was ascribed to radioactive recombination of the excited surface electrons with cavities in the gold particles.The fluorescence intensity shrunk as the average size of the gold particles increased.