Size-Selective Formation of Hexagonal Silver Nanoprisms in Silver Citrate Solution by Monochromatic-Visible-Light Irradiation
Size-Selective Formation of Hexagonal Silver Nanoprisms in Silver Citrate Solution by Monochromatic-Visible-Light Irradiation
复制标题
单色可见光照射在柠檬酸银溶液中选择性形成六角银纳米棱柱
DOI：
10.1021/jp304504c
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发表时间：
2012
期刊：
影响因子：
3.7
通讯作者：
and Y. Maeda
中科院分区：
文献类型：
--
作者：
H. Tanimoto;S. Ohmura;and Y. Maeda
柠檬酸银溶液被来自发光二极管（LED）的单色光照射。在可见光照射下，在一定能量密度（Φthres）以上的吸收光谱中观察到特征吸收峰（Abshex）。通过透射电子显微镜观察证实了六方银纳米棱镜的形成;这些六边形在面内方向上的尺寸随着ELED（标称峰值能量）的增加而减小。从Abshex的注量演化研究了纳米棱镜的形成过程，这是由于纳米棱镜的局域表面等离子体共振。随着ELED的降低，Φ thres呈指数增加，超过Φthres的Abshex生长速率（ΔAbshex/ΔΦ*，Φ* = Φ - Φthres）呈线性降低。ΔAbshex/ΔΦ* vsELED数据表明，ΔAbshex/ΔΦ* 在ELED = 1.9 eV时变为零。一般情况下，Abshex在Φ* = 0处的峰值能量与ELED接近。这些结果表明，在低于Φthres的可见光照射下，晶胚形成，部分晶胚转变为六方银纳米棱柱。胚胎向纳米棱镜的转化受入射光诱导的共振过程控制。此外，纳米棱镜的形成是由光子能量大于1.9 eV的可见光照射诱导的。
Silver citrate solution was irradiated by monochromatic light from light-emitting diodes (LEDs). Under visible-light irradiation, a characteristic peak (Abshex) was observed in the absorption spectrum above a certain value of fluence (Φthres). The formation of hexagonal silver nanoprisms was confirmed by transmission electron microscopy observations; the size of these hexagons in the in-plane direction decreased with increasingELED(nominal peak energy). The formation process was investigated from the fluence evolution of Abshex, which was due to the localized surface plasmon resonance of the nanoprisms. With decreasingELED, Φthresshowed an exponential increase and the growth rate of Abshexbeyond Φthres(ΔAbshex/ΔΦ*, Φ* = Φ – Φthres) showed a linear decrease. The ΔAbshex/ΔΦ* vsELEDdata indicated that ΔAbshex/ΔΦ* became zero atELED= 1.9 eV. Generally, the peak energy of Abshexexpected at Φ* = 0 was close toELED. These results indicated that embryos were formed by visible-light irradiation below Φthres, and some of them were converted into hexagonal silver nanoprisms. The conversion of embryos into nanoprisms is governed by a resonant process induced by the incident light. Further, the formation of nanoprisms is induced by visible-light irradiation with photon energy greater than 1.9 eV.