Langmuir—Blodgett light-emitting diodes of poly(3-hexylthiophene) : electro-optical characteristics related to structure

Poly(3-hexylthiophene) Langmuir-Blodgett (LB) films have been used as the emitting layer in light-emitting diodes (LEDs). In order to develop further the device and increase the quantum efficiency by balancing the number of injected holes and electrons, two different approaches have been taken. Following the more conventional way, LB films of hole- and electron-transporting materials have been used in a separate layer and/or in a blend with the emitting material. Insulating polyaniline LB films at the electrode interfaces have also been used in order to control the operation. A simple model relating the electro-optical characteristics of the LED to its structure has been proposed.