At the growth stage,
large particles form with different morphologies and sizes through diffusional growth or aggregation. The reaction is finished in less than 1 min, and these two stages are tough to www.selleckchem.com/products/BIRB-796-(Doramapimod).html be distinguished separately and potentially take place at the same time. So, the growth rate is in the kinetic-controlled regime, which is classified as kinetically controlled overgrowth in a minireview [14]. Anisotropic overgrowth occurs due to a faster rate of atomic addition or small particles aggregation than that of adatom diffusion, with high-energy facets growing more quickly than low-energy facets; hence, fast growth rate is indispensable to appearance of flower morphology. Larger quantity of ammonia leads to more fast reaction rate and more Ag0 atoms forming at initial stage. Consequently, the adatoms and small particles have less time to diffuse or aggregate. Compared to sample P400 denoting 400 μL NH3•3H2O injected, in P600 reaction condition, more adatoms burst as soon as NH3•3H2O is added; high growth rates occur at areas with high curvature of the rods; and secondary branches begin to grow from the main branches. This can explain the appearance of aforementioned turning point displayed in Figure 1C. Further increasing
the NH3•3H2O addition, there is an insufficient supply of silver atoms to support the growth stage giving rise to flower cluster formation with abundant rods but limited rod length however in Figure 1D. P200 has more time to diffuse and Fedratinib in vivo forms large rods with the length as long as 1 μm. This is well displayed in the extinction spectra (Figure 2) in which the surface plasmon resonance peak is red shift compared to others although they all exhibit broad spectra from visible to near-infrared range due to complex morphology and hybridization of plasmons associated with
longitudinal plasmon resonance of rods and multipole resonance. With increasing the amount of NH3•3H2O, less diffusion time leads to short rods and the main surface plasmon resonance peak is slightly blue shift and the full width at half maximum becomes larger. When it comes to 800 μL, there is a buy AZD8186 lifting in near-infrared region probably because flower clusters with abundant rods form as displayed in Figure 1D and multipole resonance becomes dominant. Figure 2 The extinction spectra of the flower-like Ag nanostructures. The extinction spectra of the flower-like Ag nanostructures prepared with PVP and different amounts of catalyzing agent NH3•3H2O. In the legend of the figure, for simplification, the samples are denoted as P200, P400, P600, and P800, respectively. ‘P’ stands for ‘PVP’ and the followed number stands for the volume of NH3•3H2O added. The crystal structure of the samples was characterized by XRD as presented in Figure 3. Different peaks corresponding to different plans have been marked. Obviously, FCC structures exist in all the samples.