Development of Multicolor Polymer Electroluminescent Devices by the Photobleaching Method

点击翻译按钮获取中文摘要

A novel "photobleaching method" for the fabrication of micropatterned multicolor organic electroluminescent devices has been developed. From single layer polymer EL devices with a structure of indium-tin oxide (ITO) / polyvinylcarbazole dispersed with fluorescent dyes / cathode metal, EL emission is observed originating from the dispersed dyes. When a yellow-emitting fluorescent dye, rubrene, is doped to the polymer layer, together with blue dye, the device emits yellow light from the doped rubrene. In order to tune the emission color, the rubrene-doped polymer layer is, first, exposed to ultraviolet (UV) light after formed by spin coating so that rubrene is photooxidized and becomes non-emissive. Due to this photobleaching process, the UV exposed area emits in blue while the non-exposed area yellow. By using a fine-patterned photomask during UV irradiation, micropatterned multicolor EL devices were successfully fabricated. Red, green blue, three color devices have also been developed by using appropriate fluorescent dyes as dopants.