In the case of silver nanocubes intense XRD peak is the (200). This intense peak is explained due to the presence of {100} facet. How these are related.
Reference
http://www.sciencedirect.com/science/article/pii/S0925838813024389
This is the same effect as with textured samples, I think. In "normal" situation with powder XRD you have the same number of all the orientations of particles in three spacial axes. This gives you "standard" pattern, as in the database. But in the case of preferential orientation of particles you have increased intensities of some peaks. Namely, the peaks which are related to the crystallographic planes, which become "ordered" due to this preferential orientation (in most cases parallel or perpendicular to this orientation).
In case of cubic particles it is obvious, that on substrate most of them will be lying on one of the facets, which are all crystallographically equivalent. So, there is a preferential orientation and, thus, you get the increased intensity of the peak(s) related to the plane(s), ordered by this orientation (this is not a good wording, but I think you understand the general idea).
In addition to Prof. Alexander answer,....in principle of solid state, it is obvious that term of crystal lattice (constituent particles in 3-D and in ordered arrangement), lattice sites (fixed position on which constituent particles are present), and unit cell (a smallest repeating unit in space lattice to generate a complete crystal lattice, in your case, cube). So, in case of nanocubes (i.e. facets), which are constructed by constituent particles in the corner fixed position, could be identified by their position in 3-D (space) using Miller indexes or hkl planes. In case of facet (200) and (100), the crystallographic orientations and plane-directions are the same (or parallel) so that peaks of XRD pattern for instance, a cube {facets (200) and (100)} will reveal a peak with more intense-peak.
- Badges
- Science topic
- Similar topics
- Chemistry
- Nanotechnology
- Nanoparticle Research