Solution processed organic light-emitting diodes with improved cathode interfacial structure

Interface and its engineering are critical to achieve efficient organic light-emitting diodes (OLEDs). In this presentation, we would like to present a new type of electron transport layer (ETL) based on metal oxide between emissive layer and metal electrode. The metal oxide synthesized by sol-gel process and can be solution processed on top of the emissive layer. The efficiency of OLEDs based on green polyfluorene polymer has found increased significantly, from 15 lumen/watt to 19 lumen/watt compared with our previous cathode structure of Cs(2)CO(3)/Al. The electrochemical properties and electronic structure of the ETL, and energy alignment at the interface are examined to understand the function of this ETL and the contribution to the improvements for device performances. We will present the details of the analysis and the composition of the materials in the presentation.