Fluorescent - Page 4

Researchers from the University of Michigan developed metal-free phosphorescent OLED emitters. The idea is that if the emitter molecules cannot vibrate, they cannot release energy and light and so more energy is converted into light. At first they tried creating a stiff lattice (crystalize the emitters) - this achieved 55% light conversion (better than the 25% of regular fluorescent OLEDs, but not as good as the 100% achieved by heavy metal doping).

But this method cannot be adopted for commercial OLEDs easily, and so the second method they tried is to tweaking the organic molecules so that they form structural bonds with a transparent polymer (they attach "like magnets"). This is an easier process, but it achieved only 24% efficiency - similar to a regular fluorescent OLEDs. But they are working on ways to improve this. The important point is that they demonstrated that increasing the intermolecular bonding strength could efficiently suppress the vibrational loss of the phosphorescent light.

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.

Ason Technology was established in 2006 in Japan to develop OLED lighting technologies. The company finally unveiled their first OLED lighting panel during the FPD International 2013 exhibition last month.

Ason's panel use Multi-Photo-Emission (MPE), which is a stacked emitter architecture, which is also used by Lumiotec. Usually MPE panels use about 3 layers, but Ason managed to stack 10 or more emitting layers which enables them to reach a very high brightness and CRI. Ason also developed their own diffusion reflection layer so that the emitted color does not change even when viewed from different angles.

Updated: This story had some inaccuracies and is now updated with new information from First-O-Lite

China's First-O-Lite says they developed an efficient (111.7 lm/W at 1,000 cd/m²) hybrid OLED lighting device (2 cm²). This is a hybrid device that uses a fluorescent blue emitter along with red and blue phosphorescent emitters. The company says that this is probably the most efficient hybrid OLED device ever produced that can meet the Energy Star color requirements.

First-O-Lite has established a volume production fab and will soon start producing OLED panels. These will feature over 55 lm/W (at 3,000 cd/m²) and will use the company's external light extraction technology.

Cynora is a German startup established in 2003 that developed copper-based OLED emitter systems. In October 2012 the company unveiled a mostly-solution-based flexible OLED prototype, developed in collaboration with InnovationLab. Last month Germany’s BMBF launched the cyCESH project which aims to develop soluble (printable) materials for low-cost high efficiency OLED lighting devices. Cynora is the leader of the consortium in this €6 million project, together with Novaled and the University of Regensburg.

Cynora's technology is interesting and the company's CEO Dr. Tobias Grab and the company's Business Development manager, Dr. Mathias Mydlak, were kind enough to provide the information for this article explaining the company's technology.

In December 2012 we posted about Japan's Kyushu University new rare-metal free fluorescent OLED emitter materials that achieve 100% emission efficiency. Now the International Society for Optics and Photonics (SPIE) released a new video featuring Kyushu's professor Chihaya Adachi. Following a rather long introduction into his lab and his own biography, professor Adachi explains their thermally activated delayed fluorescence (TADF) technology (also called hyperfluorescence).

Adachi says that are seeking a commercialization partner, and they still need to study the degradation mechanism and expand the emission spectrum. Towards the end of this video you can view a couple of prototype monochrome (green) panels that use their new emitters.

IHS iSuppi posted a "virtual teardown" for the upcoming Galaxy S4, saying that the bill of materials is about $236 (for the HSPA+ S4 with 16 gigabytes of NAND flash). According to iSuppli, the 5" Full-HD Super AMOLED display costs $75. As the 4.8" WXGA AMOLED on the S3 costs $65, this represents the largest cost increase for the S4 compared to its predecessor (The cost of making an S3 is estimated at $208). The cost of the AMOLED display is over 30% of the cost of the entire S4.

Other expensive components on the HSPA+ S4: the Exynos 5 processor at $30, memory (NAND + Flash) at $28, the two cameras at $20, the UI and sensor subsystem at $16 and the HSPA+ chip at $16. You can see the complete list on the table above, which includes also the S4 LTE and S3 Built-Of-Materials (BOM) estimates.

LG Chem sent us an update on their OLED lighting program, with some very exciting news. Besides planning flexible OLED lighting panels in July 2013 (I already posted about this earlier), LG says they have successfully developed high efficiency OLED lighting panels (80 lm/W, similar to CFLs) that will enter mass production in July 2013 (together with the flexible panels). These will be the world's most efficient OLED panels (beating LG Chem's current 60 lm/W panels).

The upcoming 80 lm/W will feature 20,000 hours lifetime (LT70), 3000K color temperature, brightness of 75 lumens (3000 cd/sqm) and a CRI of 85. The first 80 lm/W panels will be 100x100 mm in size and only 1.1 mm thick (thinner than LG's current panels which are 1.8mm thick). LG says that these panels will have a surface temperature of 26 degrees - roughly around room temperature (this is better than their current panels).

We've just got word from LG Chem that the company now plans to start mass producing the world's first flexible OLED lighting panels in July 2013 (and also high-efficiency 80 lm/W rigid panels). This is exciting news and if LG Chem will indeed go through with this plan it will be an important milestone for OLED lighting. Those OLED panels will be 200 x 50 mm in size and will feature 45 lm/W and a color temperature of 4,000K.

LG's flexible panels are only 0.33 mm thick and weigh under 8 grams - which not only allows new design possibilities but is also useful for energy saving for applications sensitive to weight (electric cars, airplanes, submarines, etc).

OSRAM is presenting a new luminaire (called the Rollercoaster) that features transparent OLED panels. OSRAM says that they have made some significant advances and they now plan to start series-production of such panels in 2014. 

The Rollercoaster looks like a glass and metal sculpture when turned-off and has a mobius-form (and so looks like a rollercoaster). It has 30 rectangular OLED panels, each with an active area of 18x6.5 cm. The OLEDs feature an efficiency of 20 lm /W and a transparency of 57% (which they say is the highest yet for such large panels. Fraunhofer's TABOLA transparent panels, which we reviewed back in April feature 45% transparency).