Nico Meyer

Highly efficient yellow organic light emitting diode based on a layer-cross faded emission layer allowing easy color tuning

An easy way to adjust the color of yellow organic light emitting diodes (OLED) is realized by basing the emission layer on a cross-fading zone of two unipolar-conducting host materials doping parts of it either with a red or green phosphorescent emitter at varying thickness ratios. At color coordinates of 0.47/0.50, a current efficacy of 42.2 cd/A (16.2% external quantum efficiency) and a power efficacy of 32.9 lm/W (1000 cd/m2) are measured without light extraction enhancement. Mixed-host emission layer OLED without cross-fading are processed for comparison. Exciton distributions are studied. The concept is suggested to be useful for white OLED.

Layer Cross-Fading at Organic/Organic Interfaces in OVPD-Processed Red Phosphorescent Organic Light Emitting Diodes as a New Concept to Increase Current and Luminous Efficacy

The current and luminous efficacy of a red phosphorescent organic light emitting diode (OLED) with sharp interfaces between each of the organic layers can be increased from 18.8 cd/A and 14.1 lm/W (at 1,000 cd/m 2 ) to 36.5 cd/A (+94%, 18% EQE) and 33.7 lm/W (+139%) by the introduction of a layer cross-fading zone at the hole transport layer (HTL) to emission layer (EL) interface. Layer cross-fading describes a procedure of linearly decreasing the fraction in growth rate of an organic layer during deposition over a certain thickness while simultaneously increasing the fraction in growth rate of the following layer. For OLED processing and layer cross-fading organic vapor phase deposition (OVPD) is used. The typical observation of a roll-off in current efficacy of phosphorescent OLED to higher luminance can be reduced significantly. An interpenetrating network of a prevailing hole and a prevailing electron conducting material is created in the cross-fading zone. This broadens the recombination zone and furthermore lowers the driving voltage. The concept of layer cross-fading to increase the efficacies is suggested to be useful in multi-colored OLED stacks as well.

52.3: Invited Paper: OLED Manufacturing by Organic Vapor Phase Deposition

The current status of the development of Organic Vapor Phase Deposition technology (OVPD) for the manufacturing of OLEDs will be reviewed. The basic OVPD principle is explained and typical performance data will be presented. Starting from a small scale R&D setup, the development of larger OVPD systems up to the first mass production unit is described. Special emphasis is put on the scalability of the process. The successful up-scaling of the OVPD principle is supported by extensive numerical modeling that is also described.

27.4: Modeling and Fabrication of Organic Vapor Phase Deposition (OVPD) Equipment for OLED Display Manufacturing

The Principle of Organic Vapor Phase Deposition (OVPD) using AIXTRONs proprietary Close Coupled Showerhead technology will be presented and discussed. This alternative deposition technology enables substrate scalability and multiple layer deposition with high growth rates and high material efficiency. CFD-Simulations for the temperature distribution and the mass fraction of typically used Alq3 reveal excellent process control required for homogeneous deposition and reproducible mass production. The actual production equipment will be discussed.

Introduction to Organic Vapor Phase Deposition (OVPDⓇ) Technology for Organic (Opto-)electronics

In this chapter, the organic vapor phase deposition (OVPDⓇ) technology combined with the Close Coupled Showerhead (CCS) technology for the fabrication of sophisticated opto-electronic organic devices based on open literature will be shortly reviewed. Typically, organic (opto-)electronic devices are fabricated by vacuum thermal evaporation (VTE), which is in contrast with the OVPDⓇ technology. The deposition of single organic films, the morphology control by OVPD and the proposed benefits of mixing organic materials, and applying non-sharp interfaces for the overall organic light emitting diode (OLED) performance will be discussed.