Technical / Research - Page 37

The 3-year German project IMAGE (innovation printable electrode materials for high performance OLEDs and OPVs) has been successfully completed. The project partners (which include Fraunhofer COMEDD and Carnot MIB) demonstrated novel organic transparent electrodes, which are arranged on a backing film and enable flexible electronic components.

The performance of these electrodes was demonstrated using flexible OLEDs and OPVs. COMEDD explains that new electrodes could replace conventional transparent metal oxides, such as ITO - which is less cost effective and less flexible. COMEDD can now manufacture flexible organic devices using the new electrodes, and the project partners are looking for industry partners to commercialize this technology.

Update: it turns out that researchers from Durham University have also published an article on OLEDs for Li-Fi networks, just a couple of months ago

Researchers from the University of St. Andrews in Scotland are investigating how OLEDs can be used to enable better Li-Fi networks. A Li-Fi network uses rapid flickers in room lighting to send communication signals which complements Wi-Fi and increase bandwidth.

The idea is that patterned OLEDs are placed on top of small blue LEDs (which are themselves driven by high-speed chips). The OLEDs actually perform as a color conversion layer - they multiplex the signals into other colors. The researcher imprint a diffraction grating into the OLED panels, and these gratings control the direction in which the signal was sent. This is used for relatively slow-speed direction-controlled communication - to provide increased security or reduce power consumption.

Aixtron and Manz signed a strategic cooperation agreement for OLED manufacturing. The two companies will co-develop solutions for efficient OLED production, based on Aixtron's OVPD technology.

Aixtron says that together with Manz, they plan to develop a Gen-8 (2300x2500 mm) system that can deposit OLED materials efficiently. Aixtron's part in this collaboration is the further development of OVPD process technology, while Manz will contribute its experience in purifying and handling large-scale glass substrates and the development and manufacturing of large vacuum systems. Aixtron and Manz will assemble a demonstration Gen-8 system in the coming months at one of Aixtrons's clean rooms.

Fluxim released a new version (3.4) of its setfos simulation software used to study OLEDs and OPVs. The new version 3.4 is a major improvement with respect to drift-diffusion modeling and light-outcoupling simulation. Some of the major improvements are:

• Modeling of electrical impedance spectra in the presence of charge traps
• Improved convergence for the steady-state drift-diffusion solver
• Improved heterojunction interface model
• Light extraction from arbitrary stacks of coherent and incoherent layers

As part of the Horizon 2020 program, the EU published a call for companies to submit OLED lighting research (and innovation) project proposals. The EU will help with "a small contribution". The projects should focus on materials, process and device technology for OLED lighting and will have to provide a demonstrator at the end.

The EU's final aim is to realize OLED devices over larger surfaces, with higher brightness, larger uniformity and longer lifetimes. According to the EU, OLED lighting panels should reach an energy efficacy of over 100 lm/W and a lifetime of a several hundred hours at LT97. The EU are looking for breakthroughs that will enable production costs of 1€/100 lm.

Reports from Korea suggest that LG Display and Merck are in talks to co-develop OLED ink jet printing materials. Merck is already supplying evaporable OLED materials to LG Display for their OLED TVs, and now they want to also supply soluble materials for LGD.

Merck is focused on OLED printing technologies over evaporation technologies as the technological advantages will enable cheaper large area panels. According to a Merck presentation released earlier this year, it seems that Merck wants to become an OLED solution provider, not just a material supplier as this will maximize the value for both Merck and its customers. The company currently has around 80 OLED R&D experts and around 1,400 related patents.

Apple continues to file patents for new OLED technologies - a few days ago the USPTO unveiled a new patent that describes OLED displays with integrated thermal sensors. The idea is that OLED change their color and brightness as the temperature changes - they get dimmer when they are hot. This mostly effect red OLEDs. If you measure the heat of different areas in the screen (which may get warmer because they are close to a radio transmitter for example) you can compensate and get more accurate colors.

Apple's patent describes a system that integrates the sensors into the display itself, and these sensors can be used to check the temperature of different zones in the display - or even each individual pixel. A software controller is used to determine how much compensation is required for each OLED pixel.

Kateeva is a US based startup that was established in 2009 to develop OLED ink-jet deposition technology originally developed at MIT. The company has been been in stealth-mode for years, and now finally they have unveiled their technology and system, branded YIELDJet.

So YIELDJET is an inkjet printing system that can be used to produce OLEDs in high volume. Kateeva claims that their system, the first one engineered from the ground up for OLED mass production, will dramatically improve yields and drive production costs lower. Kateeva says that this was achieved by three major technical breakthroughs: is features a production-worthy pure nitrogen process chamber, which doubles the lifetime in certain applications, it reduces particles by as much as 10X thanks to a specialized mechanical design and it offers exceptional film coating uniformity with a process window that’s 5X wider than standard technologies.

Researcher from Korea's Advanced Institute of Science and Technology (KAIST) developed a new transparent OLED electrode. They report that this electrode material, developed using colloidal lithography, is efficient, transparent and avoid the "haziness" apparent with thin metal or oxide based electrodes.

The researchers have already obtained patents for this invention in Korea and they hope that this technology could be commercialized in transparent OLEDs within three years.

Reseachers from the Universities of Bonn, Regensburg, Utah and the MIT developed a new method to make triplets radiate directly in OLEDs rather than harvesting the triplets by reverse intersystem crossing to generate delayed fluorescence. Basically this means they enabled phosphorescence OLEDs without any heavy atoms at room temperature.

The researchers created new emitter molecules that can store electrical energy for significantly longer than is conventionally assumed. This means that these molecules can exploit the spontaneous jumps in spin orientation in order to generate light - so the energy that is lost as heat in regular fluorescent OLEDs is released as light in those molecules.