DIFFUSION IN ORGANIC CRYSTALS.
Semi-annual technical rept., 1 Oct 65-31 Mar 66.
FRANKLIN INST RESEARCH LABS PHILADELPHIA PA CHEMISTRY DIV
Pagination or Media Count:
Studies on the diffusion of phenanthrene and fluorence in anthracene crystals showed that the general order of magnitude of diffusivity is comparable to self-diffusion in the case of phenanthrene and three to six times slower in the case of fluorene. Anisotropy can be observed for impurity diffusion. The diffusion rate perpendicular to the ac plane is generally two to three times faster than that perpendicular to the ab plane. Evidence for sub-grain boundary diffusion in addition to a slower lattice diffusion process was obtained in the case of phenanthrene and self-diffusion in melt-grown anthracene crystals. Melt-grown anthracene crystals were evaluated by carrier trapping lifetime studies. In general the longest lifetimes are obtained in crystals where care has been taken to exclude air when zone refined material is transferred to a crystal growing environment. Attempts were made to control the orientation of anthracene crystals grown from the melt. The seed crystal technique appears to be the most successful method judging by the results obtained so far. Author
- Physical Chemistry
- Solid State Physics