MOLECULAR LIGHT-EMITTING-DIODES USING QUINQUETHIOPHENE LANGMUIR-BLODGETT-FILMS

We report extended studies on electroluminescence from molecularly thi n semiconducting Langmuir-Blodgett films of quinquethiophene. The effe ct of the thickness of active layer and cathode electrode material has been investigated. From all these devices, greenish electroluminescen ce (visible in a dark room) has been observed with quantum efficiencie s of the order of 10-3%. Even five or nine layers of Langmuir-Blodgett films yield the same luminance as thicker films. The electroluminesce nce spectrum showed a profile identical to the photoluminescence spect rum. (C) 1995 American Institute of Physics.