Novel materials and techniques of fabrication for organic light emitting diodes.

摘要

The present dissertation work is devoted to the utilization of novel materials for various layers of the organic light emitting diodes (OLEDs). The first chapter of the thesis is the introduction into OLED's structure and basic principles of operation. The influence of the structure on the device performance as well as functions of different OLED layers is considered.; The second chapter describes the utilization of transition metal nitride semitransparent conductive films as a new class of anode materials for the OLEDs, alternative to conventionally used indium-tin oxide.; The third chapter has three novel concepts. The first is the utilization of cyclometallated iridium complexes as new materials for hole-blocking layer (HBL) phosphorescent OLEDs. The second is the novel host-guest approach to the HBL architecture, and the third is the introduction of the electron blocking layer (EBL) in order to prevent electron and exciton leakage to the hole transporter layer (HTL) and confine excitons within emissive layer. The EBL prevents emission from the HTL and dramatically increases the device efficiency particularly for blue phosphorescence OLEDs.; The fourth chapter demonstrates the application of iridium and platinum emissive cyclometalated complexes as HTL, ETL and host materials for phosphorescence OLEDs. The all-iridium OLEDs, which contain only iridium complexes in all organic layers, have been fabricated and proved to be highly efficient. Systematic studies on influence of some particular properties of the layer material on the device performance are described.; The fifth chapter describes white electroluminescence from single dopant as an emissive material. The high efficiency white phosphorescence OLEDs with only single dopant as an emitter are reported.; Chapter six describes organic vapor phase deposition (OVPD) as a novel technique of organic thin films deposition alternative to conventionally used vacuum thermal evaporation. OVPD has been used for fabricating OLEDs, doped films, charge-transfer salt films, as well as studying the deposition of high molecular weight compounds (>1000 amu).