Kinetic Studies of the Photogeneration of Silver Nanoparticles
Kinetic Studies of the Photogeneration of Silver Nanoparticles
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DOI：
10.1021/jp200161j
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发表时间：
2011-05-26
影响因子：
3.7
通讯作者：
Nesbitt, David J.
中科院分区：
文献类型：
--
作者：
Baker, Thomas A.;Monti, Oliver L. A.;Nesbitt, David J.
稳定、强拉曼活性的银纳米颗粒是由衍射极限聚焦区域内聚合物薄膜中银离子的可见光光生成的。对发射进行光谱和时间解析，以证明信号源是衍射极限点中产生的多个银纳米粒子的表面增强拉曼散射 (SERS)。 SERS 信号的时间演化呈 S 形，Avrami 相变动力学可以很好地描述。 Avrami 转化的速率常数线性取决于照明强度，与高氯酸银起始材料的单光子光还原作为形成银纳米颗粒的限制步骤一致。渐进动力学生长 SERS 信号表现出对照明强度的线性依赖性。 Avrami 动力学分析表明转变被限制在二维范围内，这与样品类似于 10 nm 薄膜的性质一致。所提出的技术为具有长期稳定性、衍射极限分辨率的大规模周期性分子传感器阵列提供了一条新途径（
Stable, intensely Raman active silver nanopartides are photogenerated by visible light from silver ions in a thin polymer film within a diffraction-limited focal area. The emission is resolved both spectrally and temporally to demonstrate that the source of the signal is surface-enhanced Raman scattering (SERS) from multiple silver nanoparticles generated in the diffraction-limited spot. The time evolution of the SERS signal is sigmoidal in shape and well described by Avrami phase transformation kinetics. The rate constant for the Avrami transformation depends linearly on illumination intensity, consistent with single photon photoreduction of the silver percholorate starting material as the limiting step to form silver nanoparticles. The asymptotic kinetic growth SERS signal exhibits a linear dependence on illumination intensity. Avrami analysis of the kinetics indicates that transformation is constrained to two dimensions, consistent with the similar to 10 nm thin film nature of the sample. The technique presented provides a novel route to large-scale periodic molecular sensor arrays with long-term stability, diffraction-limited resolution (