Spectrally narrowed emissions occurring near an interface between a single crystal thiophene/phenylene co-oligomer and a glass substrate

Polarized emission microspectroscopy has been investigated on a single crystal of a thiophene/phenylene co-oligomer. We measured polarized emissions occurring from the thin cloven facets of the crystal mounted on a glass substrate. The polarized UV light from a mercury lamp was used for the excitation. The spectrally narrowed emissions have been observed with an unusually low excitation intensity (∼90mW∕cm2) at the parts of the substrate very close to the interface between the crystal and the substrate.