Photoinduced Shape Evolution:  From Triangular to Hexagonal Silver Nanoplates

Successfully using the solution phase, we have prepared, in large quantities, uniform hexagonal silver nanoplates developed from silver triangular nanoprims by employing a photoinduced technique. The growth process was characterized by ultraviolet−visible (UV−vis) spectroscopy, transmission electron microscope (TEM), and high-resolution transmission electron microscope (HRTEM). The UV−vis spectra showed that three bands of hexagonal silver nanoplates appear at 341 (weak), 368 (medium), and 498 (strong) nm. TEM images showed that hexagonal silver nanoplates had an average edge size of 25.9 nm and thickness of 15.7 ± 1.0 nm. The mechanism of the conversion from triangular to hexagonal nanoplates has also been studied. Triangular silver nanoplates were at first fabricated through seed-mediated growth of silver particles in the presence of trisodium citrate. Subsequently, the truncation of triangular nanoplates led to the formation of hexagonal nanoplates.