High efficiency solution processable organic light emitting diode through materials and interfacial engineering

Abstract

Solution proceessable organic light emitting diodes (LEDs) requires multilevel approaches to achieve high efficiency. Time-Dependept Density Fuctional Theory method is carried to predict the molecular parameters such as triplet energies (ET) which are important to achieve high efficiency Organic LED. This will guide the material designs. Interfacial treatment at the anode and cathode can help improve the charge injection and charge balance. The use of Nafion to modify the workfunction of Pedot:PSS increased the device efficiency for the blue phosphorescent Organic LED while flourinated alcohol can be used to modify the cathode resulting almost double of efficiency for `super-yellow' poly-(p-phenylenevinylene) Orgnic LED. We also found out that the ET of the materials can be significantly influeced by the side groups and intermolecular distance. Multilayer Organic LED can be used to confine the recombination region resulting in little change of CIE-cordinate in a wide range of luminance. Solution processable Orgnic LEDs show great promise in lowering the manufacturing cost of Organic LEDs.