Solid-to-Solid Crystallization of Organic Thin Films: Classical and Nonclassical Pathways.

ABSTRACT: The solid-to-solid crystallization processes of organic molecules have been poorly understood in view of the complexity and the instability of organic crystals. Here, we studied the crystallization of a ?-conjugated small molecular semiconductor, bis-(8-hydroxyquinoline) copper (CuQ₂), by annealing the thin films at different temperatures. We observed a classical film-to-nanorods crystallization at 80 °C, a coexistence of classical and nonclassical nucleation and particle growth at 120 °C, and a nonclassical crystal growth at 150 °C. We found that the growth of the crystals followed the following processes: particle nucleation, particle growth, particle migration, nondirectional particle attachment, and structure reconstruction. We notice that the growth of CuQ₂ particles follows an outside-to-inside process. More interestingly, our experiments suggest that the submicron CuQ₂ particles are able to migrate dozens of micrometers at 150 °C.

SUBMITTER: Wei Z 

PROVIDER: S-EPMC6711356 | biostudies-literature | 2018 Jun

REPOSITORIES: biostudies-literature