Light-emitting Diodes based on organic semiconductors (OLEDs) have many features, which show great promise for flat-panel display applications and lighting applications. Based on the very high efficiency of the diodes (e.g. for green diodes the efficiency is higher than for inorganic LEDs) a possible future market will be in lighting applications, since OLEDs are optimal for diffuse area lighting.
Fraunhofer IPMS offers customer/application-specific developments based on highly efficient OLEDs in combination with the novel fabrication technology based on the world-wide first vertical In-line fabrication system for organic light emitting diodes.
Especially for OLED light sources the cost pressure on the fabrication is enormous. The Fraunhofer IPMS will show on the fair the first time a novel fabrication combination to achieve low cost fabrication for lighting applications.
One important aspect for fabrication cost is the used ground contact, which is commonly build by the use of ITO, a widely used contact material for LCD displays. Due to grow of display fabrication the cost for ITO increases drastically over the past 3 years by a factor of three. For low cost fabrication a low cost alternative for ITO have to be used. The Fraunhofer IPMS makes investigations, inside of the European largest OLED lighting project named OLLA (High brightness OLEDs for ICT & Next Generation Lighting Applications), to replace ITO by a new low cost material named ZAO (Aluminium doped ZnO) . Large area highly efficient OLEDs on this low cost anode material will be shown on the fair.
Additionally for lighting market it is generally expected that the manufacturing methods have to become more efficient to achieve large market penetration. OLED based on small-molecule organic semiconductors are currently manufactured by point-source evaporation using cluster equipment, leading to large losses of organic materials and long tact times. The Fraunhofer IPMS offers developments using a worldwide unique fabrication technology, the vertical In-Line deposition technique. The organic layers are dynamically deposited during the vertical transportation of the substrates inside the Applied Films Machine VES400. Based on this transportation principle and the use of organic line sources it is possible to improve throughput, masking and organic material usage. The Fraunhofer IPMS will show newest lighting demonstrators fabricated on this In-Line system.