Remarkable temperature dependence of electric field-induced change in fluorescence spectra of pyrene doped in a polymer matrix

Electrofluorescence spectra as well as fluorescence spectra of pyrene doped in a polymer film have been measured at various temperatures in the region of 70-293 K. As the temperature decreases, fluorescence with a peak at 395 nm which gives a very different response to an applied electric field from other fluorescence emissions increases. Besides the structured monomer fluorescence with a peak at ∼380 nm and sandwich-type excimer fluorescence with a peak at ∼470 nm, three types of partially overlapped excimer fluorescence exist at low temperatures for pyrene doped in a PMMA film at high concentrations.