Stolle Heike Lisa Kerstin Stephanie, Csáki Andrea, Dellith Jan, Fritzsche Wolfgang
Department of Nanobiophotonics, Leibniz Institute of Photonic Technology (IPHT), Albert-Einstein-Straße 9, D-07745 Jena, Germany.
Competence Center for Micro- and Nanotechnologies, Leibniz Institute of Photonic Technology (IPHT), Albert-Einstein-Straße 9, D-07745 Jena, Germany.
Nanomaterials (Basel). 2021 Jan 18;11(1):245. doi: 10.3390/nano11010245.
In this work we investigated methods of modifying gold nanospheres bound to a silicon surface by depositing palladium onto the surfaces of single nanoparticles. Bimetallic Au-Pd nanoparticles can thus be gained for use in catalysis or sensor technology. For Pd deposition, two methods were chosen. The first method was the reduction of palladium acetate by ascorbic acid, in which the amounts of palladium acetate and ascorbic acid were varied. In the second method we utilized light-induced metal deposition by making use of the plasmonic effect. Through this method, the surface bond nanoparticles were irradiated with light of wavelengths capable of inducing plasmon resonance. The generation of hot electrons on the particle surface then reduced the palladium acetate in the vicinity of the gold nanoparticle, resulting in palladium-covered gold nanospheres. In our studies we demonstrated the effect of both enhancement methods by monitoring the particle heights over enhancement time by atomic force microscopy (AFM), and investigated the influence of ascorbic acid/Pd acetate concentration as well as the impact of the irradiated wavelengths on the enhancement effect. It could thus be proven that both methods were valid for obtaining a deposition of Pd on the surface of the gold nanoparticles. Deposition of Pd on the gold particles using the light-assisted method could be observed, indicating the impact of the plasmonic effect and hot electron for Pd acetate reduction on the gold particle surface. In the case of the reduction method with ascorbic acid, in addition to Pd deposition on the gold nanoparticle surface, larger pure Pd particles and extended clusters were also generated. The reduction with ascorbic acid however led to a considerably thicker Pd layer of up to 54 nm in comparison to up to 11 nm for the light-induced metal deposition with light resonant to the particle absorption wavelength. Likewise, it could be demonstrated that light of non-resonant wavelengths was not capable of initiating Pd deposition, since a growth of only 1.6 nm (maximum) was observed for the Pd layer.
在这项工作中，我们研究了通过在单个纳米颗粒表面沉积钯来修饰与硅表面结合的金纳米球的方法。由此可以获得双金属金 - 钯纳米颗粒，用于催化或传感器技术。对于钯沉积，选择了两种方法。第一种方法是用抗坏血酸还原醋酸钯，其中醋酸钯和抗坏血酸的量是变化的。在第二种方法中，我们利用了等离子体效应通过光诱导金属沉积。通过这种方法，用能够诱导等离子体共振的波长的光照射表面键合的纳米颗粒。然后颗粒表面上热电子的产生还原了金纳米颗粒附近的醋酸钯，从而得到覆盖钯的金纳米球。在我们的研究中，我们通过原子力显微镜（AFM）监测增强时间内的颗粒高度来证明两种增强方法的效果，并研究了抗坏血酸/醋酸钯浓度的影响以及照射波长对增强效果的影响。因此可以证明两种方法对于在金纳米颗粒表面获得钯沉积都是有效的。使用光辅助方法可以观察到钯在金颗粒上的沉积，这表明等离子体效应和热电子对金颗粒表面醋酸钯还原的影响。在抗坏血酸还原法的情况下，除了钯沉积在金纳米颗粒表面外，还生成了更大的纯钯颗粒和扩展的簇。然而，与光诱导金属沉积（光与颗粒吸收波长共振）时高达11nm相比，抗坏血酸还原导致钯层厚得多，可达54nm。同样，可以证明非共振波长的光不能引发钯沉积，因为观察到钯层仅生长1.6nm（最大）。
