Electric-field-induced enhancement of LE fluorescence in a linked compound of carbazole and terephthalic acid methyl ester in a PMMA polymer film

Fluorescence emitted from the locally excited (LE) state of the carbazole chromophore (CZ) linked to terephthalic acid methyl ester (TPA) by a methylene chain is enhanced by an electric field in a polymer film, when the chain length is very short. It is suggested that the enhancement of the LE fluorescence results from the field-induced increase in efficiency of the back-electron transfer, which occurs through a methylene chain following photoinduced electron transfer and leads to the fluorescent state of CZ.