Role of Au nanoparticle aggregation in laser induced anisotropy of ITO transparent substrates
Role of Au nanoparticle aggregation in laser induced anisotropy of ITO transparent substrates
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DOI：
10.1016/j.jallcom.2013.09.143
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发表时间：
2014-02
影响因子：
6.2
通讯作者：
I. Kityk;J. Ebothé;N. Bercu;M. Aziz;M. Oyama
中科院分区：
文献类型：
--
作者：
I. Kityk;J. Ebothé;N. Bercu;M. Aziz;M. Oyama
一个主要的可能性，以实现光致各向异性的Au NP沉积到ITO基板上的实验示出。形成相应纳米复合物的Au NP的尺寸为20 nm、30 nm和40 nm。作为光诱导光源，我们使用了两个相干光束，来自Er：glass激光器，产生1540 nm的重复频率为15 Hz，以及它的二次谐波倍频信号在770 nm。这种效应对两束激光之间的角度以及Au NP的尺寸、颗粒间距离和与其聚集相关的拓扑结构敏感。该效应显示出缓慢弛豫到初始状态。尽管预期的20 nm，但对于30 nm形成的纳米复合材料实现了最佳条件。这可能是由于部分聚集的关键作用，甚至改变了有效晶粒尺寸。偶极-偶极以及四极-偶极相互作用的各向异性的变化的贡献进行了讨论。激发远离共振，这允许预测有效作用与纳米捕获水平重叠。因此，主要作用可能属于表面拓扑结构，并使用与各向异性直接相关的双折射进行研究。
A principal possibility to achieve the photoinduced anisotropy in the Au NP deposited onto the ITO substrate is experimentally shown. The sizes of the Au NP forming the corresponding nanocomposites were 20 nm, 30 nm and 40 nm. As a photoinducing light source we have used two coherent beam originating from the Er:glass laser generating at 1540 nm with frequency repetition 15 Hz as well as its second harmonic doubled frequency signal at 770 nm. The effect is sensitive to the angle between the two laser beams as well as to the Au NP sizes, inter-particle distances and topology connected with their aggregation. The effect shows slow relaxation to the initial state. The optimal conditions are achieved for nanocomposites formed by 30 nm despite the expected 20 nm. This one may be caused by crucial role of the partial aggregation which even changes the effective grain sizes. The contribution of the dipole–dipole as well as quadrupole–dipole interactions to the changes of the anisotropy is discussed. The excitation is far from the resonance which allow to predict that effective role play overlap with nanotrapping levels. So principal role may belongs to surface topology and which is studied using the birefringence directly connected with the anisotropy.