Shape and Internal Structure of Silver Nanoparticles Embedded in Glass

Abstract

The structural characteristics of silver nanoparticles embedded in glass by various routes of fabrication were studied in detail using high-resolution electron microscopy to find out if they are influenced by interaction with the surrounding glass matrix. Besides the formation conditions, the strength of the interaction between metal and glass governs the size-dependent changes of lattice spacings in such nanoparticles. However, determination of these changes is not straightforward because of complicated particle configurations and the interference nature of the lattice imaging technique. Imaging of lattice plane fringes and careful diffractogram analysis allowed the exclusion of any kind of tetragonal lattice distortion or transformation to hexagonal lattice type that may be deduced at first sight. Instead, the formation of twin faults in these nanoparticles turned out to be the essential structural feature and the main source of confusion about the lattice structure observed. The variety of particle forms is comparable to particles supported on oxide carriers. It is composed of single-crystalline particles of nearly cuboctahedron shape, particles containing single twin faults, multiple twinned particles containing parallel twin lamellae, and multiple twinned particles composed of cyclic twinned segments arranged around axes of 5-fold symmetry. The more twin planes involved in the particle composition, the more complicated is the interpretation of lattice spacings and lattice fringe patterns due to superposition of several twin segments.

Stabilization of antimicrobial silver nanoparticles by a polyhydroxyalkanoate obtained from mixed bacterial culture

“…These results are in agreement with the Standard Powder Diffraction card of Joint Committee on Powder Diffraction Standard (JCPDS), silver file No. 04-783 (a = 4.086Å) and in line with previous experimental reports [38,39]. For instance, Theivasanthi and Alagar reported similar crystalline structures using silver nanopowder made by electrolytic synthesis [40].…”

Transformations of gold nanoparticles investigated using variable temperature high-resolution transmission electron microscopy

“…The wide variety of structures observed experimentally and predicted theoretically [3][4][5][7][8][9], even at room temperature has limited progress towards an overall understanding of small particle structure, particularly with respect to catalysis, where environmental factors such as temperature and the presence of reactive species further modify these [10,11]. High-resolution transmission electron microscopy (HRTEM) has been at the forefront of the characterisation of nanoparticles [3,12] although the successful use of this technique requires careful consideration of current experimental limitations.…”

Structural characteristics of oxide nanosphere supported metal nanoparticles

“…Below about 5 nm size mainly single crystalline Ag and Au nanoparticles have been observed on Sto¨ber silica nanospheres. The more twin planes are involved in the particle composition, the more complicated are interpretation of lattice fringe patterns as well as evaluation of lattice spacings due to superposition of several twin segments [78,79]. In such cases unambiguous lattice analysis is impossible, except the twin planes have cozonal orientation and are imaged end-on as it is shown for the twinned Ag nanoparticle in figure 9 where the twin boundary is indicated by the arrows in the real space image (figure 9(a)) as well as in the reciprocal image ( figure 9(b)).…”