Perylene microcrystals are known to show characteristic change in the exciton fluorescence spectra depending on the crystal size less than about 200nm. However, the origin of the size-dependence is not yet clear. In this work, we have studied on individual microcrystals by a scanning near-field optical microscope (SNOM). The samples were prepared by a modified technique based on reprecipitation method. As a result, we could successfully measure the topographic and fluorescence images of perylene microcrystals with the size of ∼200nm by SNOM at room temperature. In the fluorescence spectra of the single microcrystals, free and self-trapped exciton bands were successfully observed but they did not show any critical difference from that of the bulk crystals. Some possibility of environmental difference is discussed.
ASJC Scopus subject areas
- Statistical and Nonlinear Physics
- Condensed Matter Physics