The SPR bands of the Ag crystals (nanoparticles) with an edge length of 70 to 80 nm were also observed at 470 to 520 nm, as the peaks described learn more above mutually overlap when mixtures containing Ag nanostructures of various shapes and sizes are analyzed. However, in this procedure, the formation of the Ag NWs was monitored by analyzing the SPR bands of the reaction mixture at various times (5, 15, 25, 35, and 60 min). The SPR peaks (Figure 3) can then be used to understand the mechanism of nanostructure
growth. At the early stages of the reaction (10 min), the SPR band of the Ag nanoparticles with a size in the range of 30 to 40 nm formed through the reduction of AgNO3 in the presence of TPA exhibited a wavelength of 405 nm (Figure 3(a)). After a reaction of 40 min (Figure 3(d)), an absorption selleck band appeared at 413 nm. On the other hand, Ag nanoparticles with an edge length of approximately 40 to 50 nm contained some multiply twinned crystals. As the reaction
time increased (around 50 min), the Ag crystals were converted to pentagonal 1-D structures, while the Ag nanoparticles completely disappeared. At that time, as shown in Figure 3(e), the SPR absorption band clearly changed to the characteristic two peaks at 350 and 372 nm, which are indicative of wire formation. It is important to note that these two SPR peaks appear at significantly shorter wavelengths than the SPR peaks (350 and 380 nm) of the previously synthesized wires with
diameters between 40 and 60 nm [26, 27]. As a result, the blueshift originating from a reduction in the diameter of the NWs is also related to the reduction of scattered light. In addition to the blueshift phenomenon, a narrowing of the peak width was observed upon decreasing the NW diameter. However, ILs were also an important contributor in this assembly process as TPA supports the 1-D growth of the Ag nanoparticles. Figure 3 SPR Selleckchem MRT67307 spectra measured every 10 min throughout the Ag NW synthesis. SPR spectra Exoribonuclease obtained from the reaction after (a) 5 min, (b) 15 min, (c) 25 min, (d) 35 min, and (e) 60 min (inset figures: the Ag nanostructures, at the initial reaction step, existed as Ag particles of 40 to 50 nm in diameter, and after 60 min, these Ag particles were converted into a 1-D structure approximately 30 nm in diameter). Figure 4 displays the TEM images of the synthesized Ag NWs. As shown in Figure 4I, the TEM images indicate that the diameter of each nanowire is uniform, with a narrow size distribution. The high-resolution TEM images provided further insight into the structure of the Ag NWs (Figure 4II), in which the NWs were determined to grow along the [110] direction. In particular, Figure 4II displays the tip of an individual Ag NW, and the contrast clearly confirms that the wire was equally divided by a twin plane parallel to the longitudinal axis.