Organic Electroluminescent Diode Fabricated on Indium-Tin-Oxide-Coated Polyimide Substrate as an Electro-optical Conversion Device for Polymeric Waveguides

An organic electroluminescence diode (OLED) fabricated on a polyimide substrate has been investigated for generating highspeed optical pulses at lower voltages. The OLED fabricated on a polyimide substrate shows similar device characteristics to those on a glass substrate. The, modulation performance of OLED was improved significantly by applying a positive low dc bias at low voltages. The overshoot voltage applied on the rising edge of the input voltage pulse results in a faster rise time of the optical output. The-undershoot voltage applied on the failing edge of the input voltage pulse results in a faster fall time and a decrease in the intensity of the optical output. Optical pulses of 100 MHz have been obtained from an OLED with rubrene doped in 8-hydroxyquinoline aluminum as an emissive layer with an active area of 0.01 mm(2) fabricated on an indium-tin-oxide-coated polyimide substrate.