LIGHT-EMITTING-DIODES OF POLY(3-HEXYLTHIOPHENE) LANGMUIR-BLODGETT-FILMS

Poly(3-hexylthiophene) Langmuir-Blodgett films have been used as emitt ing layers in light-emitting diodes. The effect of the film thickness and additional carrier-transport layers on current-voltage characteris tics and quantum efficiency were studied, and the electroluminescence spectra measured. Hole transporting poly(9-vinylcarbazole) was used bo th as a separate layer in a heterostructure device and in a blend with emitting material. The electron-transport material iphenylyl)-5-(4-te rt-butylphenyl)-1,3,4-oxadiazole was used in a blend with the emitting material. The connections between the diode structure and the electro -optical properties as well as operation mechanisms are discussed.