Visible region polarization spectroscopic studies of template-synthesized gold nanoparticles oriented in polyethylene
Visible region polarization spectroscopic studies of template-synthesized gold nanoparticles oriented in polyethylene
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DOI：
10.1021/jp972869i
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发表时间：
1998-01-08
影响因子：
3.3
通讯作者：
Foss, CA
中科院分区：
文献类型：
--
作者：
Al-Rawashdeh, NAF;Sandrock, ML;Foss, CA
我们已经获得了可见光范围内的偏振光谱的模板合成的金纳米粒子在聚乙烯（PE）的取向。等离子体共振消光带观察到的入射电场极化平行，垂直，并在中间角度的摩擦取向的方向是一致的，与总取向轴对齐的颗粒的长轴。对于所考虑的所有颗粒尺寸（半径16、38和60 nm），线性二色性的程度随着在提取和取向之前在模板合成步骤中沉积的金的量而增加。实验光谱同意的瑞利，麦克斯韦-加内特，和动态麦克斯韦-加内特理论的预测只有定性。所有这些处理都不能预测光谱消光强度对偏振角θ的依赖性。T矩阵散射计算表明，在38和60 nm半径的粒子中，电四极模的贡献不可忽略。计算的消光强度的θ依赖性不像实验为16 nm半径的粒子，但理论与实验的比较是更有利于更大的半径系统。这些意见的一些可能的模型进行了讨论。
We have obtained visible range polarization spectra of template-synthesized gold nanoparticles oriented in polyethylene (PE). The plasmon resonance extinction bands observed with the incident electric field polarized parallel, perpendicular, and at intermediate angles to the direction of friction orientation are consistent with the long axis of the particles being aligned with the gross orientation axis. For all particle sizes considered (radii 16, 38, and 60 nm) the degree of linear dichroism increases with the amount of gold deposited in the template synthesis step prior to extraction and orientation. The experimental spectra agree with the predictions of the Rayleigh, Maxwell-Garnett, and dynamical Maxwell-Garnett theories only qualitatively. All of these treatments fail to predict the dependence of the spectral extinction intensities on the polarization angle theta. T-matrix scattering calculations suggest that the contribution from electric quadrupole modes cannot be ignored in the 38 and 60 nm radius particles. The calculated theta-dependence of the extinction intensity does not resemble experiment for 16 nm radius particles, but the theory-experiment comparison is more favorable for the larger radius systems. Some possible models for these observations are discussed.