Blue organic light-emitting diode using 1,4-bis(1,1-diphenyl-2-ethenyl)benzene as an emitter

• Published in: Synthetic metals 2000-01, Vol.108 (2), p.95-100
• Main Authors: Yang, J.P., Heremans, P.L., Hoefnagels, R., Tachelet, W., Dieltiens, P., Blockhuys, F., Geise, H.J., Borghs, G.
• Format: Article
• Language: English
• Subjects: Application fields; Applied sciences; Electroluminescence; Electronics; Exact sciences and technology; Optoelectronic devices; Photoluminescence; Poly(phenylene vinylene) oligomer; Polymer industry, paints, wood; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Spin coating; Technology of polymers
• ISSN: 0379-6779; 1879-3290
• DOI: 10.1016/S0379-6779(99)00136-8

We report on the properties of 1,4-bis(1,1-diphenyl-2-ethenyl)benzene (PEB) as the active material for blue electroluminescent diodes. The diodes are fabricated by spin-coating of a single layer of PEB blended in a polystyrene matrix. We discuss the optimum solvent for this spin-coating process. The anode is indium–tin oxide, the cathode is evaporated aluminum. The external quantum efficiency of this simple blue diode with air-stable cathode is 0.25% at a current density of 28 mA cm −2. The two main peaks are at 455 and 480 nm. Taking into account the eye sensitivity, the diode's efficiency is about 1.2 lm/A, which for perpendicular view, corresponds to 0.4 cd/A and 0.08 lm/W. We, furthermore, have measured transient photoluminescence and electroluminescent spectra, which reveal the appearance of peaks in the diode spectrum delayed by a few hundred milliseconds compared to the main peaks.