Sonawane Apurva, Mujawar Mubarak A, Bhansali Shekhar
Department of Electrical and Computer Engineering, Florida International University, Miami, FL 33174, United States of America.
Nanotechnology. 2020 Sep 4;31(36):365706. doi: 10.1088/1361-6528/ab9788. Epub 2020 May 28.
The use of plasma processes in nanomaterial synthesis is limited by a lack of understanding of the effects of plasma treatment on the morphology and other properties. Here, we studied the effects of atmospheric plasma treatment on the morphology and optical properties of Ag nanoparticles. The Ag nanoparticles were deposited on substrates by injecting an aerosol into flowing argon gas and then treated with a low-temperature atmospheric plasma jet. After plasma treatment, the mean Ag nanoparticle diameter reduced to an average of 5 nm, which was accompanied by a blue shift of ∼70 nm in the peak of the surface plasmon resonance; these results are similar to those obtained by thermal treatment at elevated temperatures. The reduction in nanoparticle size is explained by the redox reaction that occurs on the nanoparticle surface, which is evident from the presence of AgO and AgO Raman peaks in the treated sample. The surface charge changed as a result of plasma treatment, as indicated by a large change in the zeta potential from +25.1 ± 4 mV for the untreated sample to -25.9 ± 6 mV after 15 min of plasma treatment. Surface-enhanced Raman spectroscopy of the plasma-treated films was carried out with the fluorescent dye Rhodamine 6 G, which showed a ∼120-fold enhancement in the signal intensity relative to the untreated substrates. We, therefore, conclude that cold-plasma treatment modified the surface morphology of the Ag nanoparticles, thereby enhancing their optical properties. This technique could be applied to a wide range of nanoparticle systems used in biosensing applications.
在纳米材料合成中，等离子体工艺的应用受到对等离子体处理对形态和其他性能影响缺乏了解的限制。在此，我们研究了常压等离子体处理对银纳米颗粒形态和光学性能的影响。通过将气溶胶注入流动的氩气中，将银纳米颗粒沉积在基底上，然后用低温常压等离子体射流进行处理。等离子体处理后，银纳米颗粒的平均直径减小至平均5纳米，同时表面等离子体共振峰发生了约70纳米的蓝移；这些结果与在高温下进行热处理所获得的结果相似。纳米颗粒尺寸的减小是由纳米颗粒表面发生的氧化还原反应所解释的，这从处理后的样品中存在AgO和AgO拉曼峰可以明显看出。等离子体处理导致表面电荷发生变化，未处理样品的zeta电位为+25.1±4 mV，等离子体处理15分钟后变为-25.9±6 mV，这表明了这一点。用荧光染料罗丹明6G对等离子体处理的薄膜进行表面增强拉曼光谱分析，结果表明相对于未处理的基底，信号强度增强了约120倍。因此，我们得出结论，冷等离子体处理改变了银纳米颗粒的表面形态，从而增强了它们的光学性能。该技术可应用于生物传感应用中使用的广泛纳米颗粒系统。
