This study presents the role of reaction temperature in the formation and growth of silver nanoparticles through a synergetic reduction approach using two or three reducing agents simultaneously. By this approach, the shape-/size-controlled silver nanoparticles (plates and spheres) can be generated under mild conditions. It was found that the reaction temperature could play a key role in particle growth and shape/size control, especially for silver nanoplates. These nanoplates could exhibit an intensive surface plasmon resonance in the wavelength range of 700–1,400 nm in the UV–vis spectrum depending upon their shapes and sizes, which make them useful for optical applications, such as optical probes, ionic sensing, and biochemical sensors. A detailed analysis conducted in this study clearly shows that the reaction temperature can greatly influence reaction rate, and hence the particle characteristics. The findings would be useful for optimization of experimental parameters for shape-controlled synthesis of other metallic nanoparticles (e.g., Au, Cu, Pt, and Pd) with desirable functional properties.

This study demonstrates the details on the twinned structure and growth process of V-shaped silver nanowires with different bending angles (e.g., 90°, 120°, and 135°) confirmed by high-resolution transmission electron microscopy (HRTEM). These nanowires could be synthesized by a facile but effective polyol−thermal reaction method in autoclaves (160−180 °C). The nearly uniform-size silver nanowires show an average diameter of ∼45 nm and length up to tens of micrometers. The microstructure and optical properties of the silver nanowires were characterized by various advanced techniques, including TEM, HRTEM, scanning electron microscopy (SEM), and ultraviolet−visible (UV−vis) spectroscopy. The twinned structure can occur in both silver spherical particles and nanowires, confirmed by HRTEM analysis and also simulated by molecular dynamics methods. The growth of V-shaped nanowires by two possible means was particularly investigated: (i) crystal lattice match-induced end-to-end or end-to-side fusion of two nanowires, and (ii) twinned crystal plane-induced growth. Such structural and mechanistic understanding of silver crystals would be useful for the shape, size, and property control of functional nanoparticles.

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