Lelia Cosimbescu

23.3: Distinguished Paper: High‐Efficiency Tandem Blue OLEDs

Tandem blue OLEDs using different fluorescent dopants have achieved 20 cd/A (CIEx,y = 0.14, 0.18) and 38 cd/A (CIEx,y = 0.15, 0.42) with external quantum efficiencies higher than 11%. The tandem blue OLEDs include two electroluminescent units that are connected in series with an organic intermediate connector. At an initial brightness of 1,000 cd/m2, the drive voltage of the devices can be less than 6.5 V, and the operational lifetime (T 50) of the devices is estimated to be greater than 10,000 h. We also demonstrate that the selection of electron-transporting material and an intermediate connector have significant impact on the electroluminescence performance of the tandem blue OLEDs.

P-147: Highly Efficient and Stable Blue OLED Systems

This paper will discuss combinations of a new blue dopant and a new blue host that produce superior luminance and efficiency for blue OLED devices. Furthermore, this blue system provides excellent operational stability that enables superior performance in both monochrome and full-color displays. Devices exhibiting this outstanding performance are simple in architecture, robust with respect to dopant concentration, and require no co-doping to achieve optimal performance.

Advanced materials and formulations for OLED display manufacturing

This paper describes Eastman Kodak Companys commercialization efforts to develop new materials and formulations for monochrome and full-color displays. We have found a new set of materials, and combinations thereof, that improve luminance efficiency, lower drive voltage, and increase the operational stability of OLED devices. We report the developments in formulations for blue and white OLEDs based on fluorescent dopants that provide lifetimes exceeding 10,000 hours for blue, and 50,000 hours for white OLEDs at a starting luminance level of 1000 cd/m2. A red formulation, based on a fluorescent dopant using a new host, is shown to give a record luminance efficiency of 7.8 cd/A combined with excellent color and lifetime. We have found a phosphorescent red-emitting device using a novel host material that gives an excellent efficiency of 9.6 lm/W. Further progress has been made in a new electron-transport layer to reduce display drive voltage, and thus reduce power consumption, while simultaneously increasing operational stability. We have compared this performance with currently available systems.