PRELIMINARY COMMUNICATION - MULTILAYER LIGHT-EMITTING-DIODES BASED ONCOLUMNAR DISCOTICS

Columnar discotics were used as the hole transporting layer in single layer, two layer and three layer light emitting diodes because of the unusually large hole mobility of such materials. The observations are that the onset fields are small compared with most devices using nondi scotic hole transporting layers, that these values are strongly reduce d with increasing number of layers, that the orientation of the column s along the layer film normal causes a further decrease of the onset v oltage and finally that the quantum efficiencies increase significantl y as the number of layers is increased.