Ćwik Michał, Buczyńska Dorota, Sulowska Karolina, Roźniecka Ewa, Mackowski Sebastian, Niedziółka-Jönsson Joanna
Institute of Physical Chemistry, Polish Academy of Sciences, 01-224 Warsaw, Poland.
Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, 87-100 Torun, Poland.
Materials (Basel). 2019 Mar 1;12(5):721. doi: 10.3390/ma12050721.
We report on the synthesis of long silver nanowires using the hydrothermal method, with H₂O₂ as the reducing agent. Our approach yields nanowires with an average diameter and length of about 100 nm and 160 µm, respectively, reaching the maximum length of 800 µm. Scanning electron microscopy (SEM) measurements revealed the presence of a thick, inhomogeneous poly(vinylpyrrolidone) (PVP) layer covering the nanowires, which with time becomes much more uniform, leading to well-defined extinction peaks in the ultraviolet-visible (UV-Vis) spectra. This change in morphology is evidenced also by the fluorescence enhancement behavior probed using protein complexes. Wide-field and confocal fluorescence microscopy measurements demonstrate strong, 10-fold enhancement of the protein emission intensity, accompanied by a reduction of the fluorescence decay time. In addition, for the aged, one-month-old nanowires, the uniformity of the intensity profile along them was substantially improved as compared with the as-synthesized ones. The results point towards the importance of the morphology of plasmonically active silver nanowires when considering their application in enhancing optical properties or achieving energy propagation over submillimeter distances.
我们报道了使用水热法合成长银纳米线的过程，其中以H₂O₂作为还原剂。我们的方法制备出的纳米线平均直径约为100 nm，平均长度约为160 µm，最长可达800 µm。扫描电子显微镜（SEM）测量显示，纳米线表面存在一层厚厚的、不均匀的聚（乙烯基吡咯烷酮）（PVP）层，随着时间的推移，这层PVP会变得更加均匀，从而在紫外可见（UV-Vis）光谱中产生明确的消光峰。使用蛋白质复合物探测的荧光增强行为也证明了这种形态变化。宽场和共聚焦荧光显微镜测量表明，蛋白质发射强度增强了10倍，同时荧光衰减时间缩短。此外，与刚合成的纳米线相比，对于存放了一个月的老化纳米线，沿其长度方向的强度分布均匀性有了显著改善。这些结果表明，在考虑等离子体活性银纳米线在增强光学性能或实现亚毫米距离内的能量传播方面的应用时，其形态具有重要意义。
