OLED Lifetime: introduction and market status - Page 23

Dr. Karsten Heuser, Director of OLED Lighting Technology at OSRAM Opto Semiconductors, is pleased with the excellent intermediate results. Our development team has reached a real milestone for warm white OLEDs with efficiency of 46 lm/W (CIE of 0.46/0.42 measured in the integrated sphere) and a 5,000-hour lifetime, at a brightness of 1,000 cd/m². With these significant increases, flat OLED light sources are approaching the values of conventional lighting solutions and are therefore becoming attractive for a wide variety of applications.

The color rendering index (CRI) of the almost 100 cm² prototype is 80. By March 2009, OSRAM researchers expect that a demonstrator for an energy-saving flat OLED light module comprising several tiles will be able to deliver an overall luminous flux of 500 lm from a power consumption of less than 10 W.

With their pleasant diffused light the color of which can be individually controlled OLEDs will enhance premium lighting design elements such as light tiles that can be attached to any surface. OLED light sources will be particularly welcome where their special properties as flat light sources offer a high quality of light and make a real impression in illuminated wall coverings, atmospheric canopies of light, and light partitions. For widespread applications it will be necessary to produce efficient OLEDs in large numbers at reasonably low cost an essential objective of the OPAL research project.

This breakthrough achievement in OLED lighting is a result of the OPAL research project (Organic Phosphoresce Diodes for Applications on the Lighting Market), an initiative launched by the German Federal Ministry for Education and Research (BMBF) and coordinated by OSRAM.

Summary:

• Red phosphorescent emitter functions optimally with Novaled’s proprietary technology for highly power-efficient OLEDs


• Delivers lifetime of 50,000 hours at initial brightness of 1,000 cd/sqm


• Supports market trend toward high-performance, low-voltage OLED devices

Ciba has developed a deep red phosphorescent OLED emitter that functions optimally in combination with the Novaled PIN OLED™ technology, delivering a lifetime of 50,000 hours at an initial brightness of 1,000 cd/sqm. The new material supports the market trend toward high-performance, low-voltage OLED devices for display and lighting applications.

We want to provide the market with efficient phosphorescent materials, says Rolf Drewes, Global Head of Business Line Electronic Materials at Ciba. In this project, we are developing the full color range of emitters compatible with Novaled’s proprietary OLED technology. Our deep red, the first to become commercially available, offers customers not only long-lifetime performance but also excellent thermal stability. Green and blue are now in progress.

Phosphorescent emitter materials together with low-voltage devices are mandatory for the future of the OLED industry, and Novaled is very pleased to see a key industry player developing such materials, adds Gildas Sorin, CEO of Novaled AG. This deep red phosphorescent material provides a long lifetime at a lowest operating voltage of 3.3 V as well as good power efficiency of 8.1 lm/W, making it suitable for displays as well as for completely new lighting applications. OLED technology even has potential to surpass the efficiency of energy-saving bulbs.

Made of thin organic material layers only a few nanometers thick, OLEDs are semiconductors that emit light in a diffuse way to form an area light source. In 2006, Ciba and Novaled entered an industrial collaboration to create organic dopant and transport materials for the Novaled PIN OLED™ technology, which enables highly power-efficient OLED performance.

TMDisplay has succeeded in doubling their OLED efficiency using a metal membrance. The new design allows them to run the OLEDs at half the brightness, and thus gain twice the lifetime. TMDisplay did not disclose when they will start making OLED TVs, although the new design should not delay the TVs.

They have also showed a 20.8" prototype.

Idemitsu Kosan and Universal Display Corporation today announced that they have signed an agreement to extend their collaboration to accelerate the development of phosphorescent OLED materials for use in displays fabricated through dry processing methods, such as vacuum thermal evaporation. The agreement expands the collaboration into red and green phosphorescent OLED materials, in addition to the blue materials that the two companies have been collaborating to develop since December, 2006.

In order to further expand the market for phosphorescent OLED devices, blue phosphorescent OLED materials need to be more fully developed and the quality and lifetime of red and green phosphorescent OLED materials should continue to improve. Therefore, Idemitsu Kosan and Universal Display have agreed to extend their collaboration into red and green phosphorescent OLED materials, in addition to continuing their work together on blue phosphorescent OLED materials. The collaboration is focused on matching Universal Display’s phosphorescent emitters with Idemitsu Kosan’s phosphorescent hosts and other OLED materials. Through this collaboration, both companies expect to improve efficiency and operational lifetime of their respective phosphorescent OLED materials, which in turn should help accelerate the spread of phosphorescent OLED displays and lighting products.

Idemitsu Kosan has been developing OLED materials for middle and large size panels jointly with Sony Corporation (Sony) since 2005, and Universal Display also has been working with Sony since 2001. Idemitsu Kosan and Universal Display expect the results of this collaboration to be utilized for the OLED material development for Sony products.

As for OLED lighting systems, Chung said, "It won't be long before we commercialize them," because the OLED's light emitting efficiency is currently doubling every year. The company currently achieves 50lm/W luminance, a life of 20,000 hours till the initial luminance halves and a color rendering property of more than 80 colors.

"Our cost goal is 1 euro cent per lumen," said Chung.

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Seiko Epson has a production line at its Nagano plant and aims to take orders for OLED panels by the end of the year. The plant is capable of manufacturing several thousand OLED panels a year, the daily said. The company has expanded the life span of OLED panels to more than 50,000 hours compared with the maximum life of standard OLED devices, which is typically 30,000 hours, Nikkei said.



OLED panels, which emit light when an electrical charge is passed through the surface, are lighter and thinner than existing LCD panels or plasma displays, and boast higher contrast pictures, but are also more expensive.



The company plans to start making an eight-inch business-use OLED monitor that is 2.8 millimeter thick at its thinnest part. The production line is also capable of manufacturing larger models of up to 21 inches, the daily said.

Data from spin coated devices using a common cathode and interlayer material demonstrate lifetimes for recently developed solution-processable green and red PLED materials of 78,000 hours and 67,000 hours, respectively, from an initial luminance of 1000 candelas per square meter, or cd/m2. This is equivalent to approximately 445,000 hours and 420,000 hours from an operating brightness of 400 cd/m² for these materials.

These latest lifetimes represent a 60% and 280% increase in performance for green and red materials over results that were announced in May and March of this year, respectively.

The achievement of a green PIN PHOLED(TM) phosphorescent OLED device in bottom-emission geometry with a CIE of (0.36, 0.61) of above 200,000 hours were attained by combining Universal Display's high-efficiency phosphorescent OLED materials with low-voltage Novaled PIN-OLED(TM) technology and doped transport materials.

"We expect that very low driving voltages below 2.6 V which we already achieved for Ir(ppy)3 can also be obtained for other phosphorescent green emitters" adds Jan Birnstock, VP Technology Transfer.

CMEL showcased a 4.3" AMOLED display. Sample shipments are slated for September 2007, and volume production and shipments are expected to start around December 2007. A life extends to "20,000 hours when lit at 50% luminance and 10,000 hours at 100%," a booth attendant said.

The materials and glass cover are made by DuPont.

Read more here (TechOn Asia)

The new set of materials rely on DuPont hole-injection layer (HIL) material and include those essential in the construction of an OLED display, such as light-emitting and charge-transport materials.

DuPont Displays said it has also exceeded the reported performance of other solution-based OLED materials and has measured accelerated lifetimes of the three primary colors that could translate in a display to 20,000 hours of white lifetime (which is extended by as much as five times when showing video) at a normal viewing brightness (200 cd/m2). At 1000 cd/m2 -- the standard test luminance used in the industry -- the DuPont materials have lifetimes (T50) of 14,000 hours for blue with CIE 1931 color coordinates of (0.14, 0.16), 230,000 hours for green with color coordinates of (0.29, 0.65), and 46,000 hours for red with color coordinates of (0.66, 0.34).