OLED: technology mature market still need to wait and see

Dresden University Technology in Germany Bayer building elegant wooden doors after undergoing a significant technological revolution: on the roof with the antique brick building, research and application of optical physics of the university are the organic light emitting diode (OLED) of production equipment. With different energy-saving lamps, halogen lamp and LED lighting can be made transparent by day, night to send a variety of soft film globe or distributed color fluorescence technique using OLED wallpaper.

In early 1969, chemist HerbertNaarmann in a scientific paper put forward special ideas as semiconductor polymer. 21 years later, JeremyBurroughes and colleagues from the Cavendish laboratory research group at the University of Cambridge made the first light emitting diode with a plastic polymer. The production principle is very simple, paste the plastic coated on the substrate for hardening, the substrate on the strong enough current, the surface will be issued a yellow green light. The success of the experiment has aroused people's great interest, because the plastic is easier to process than the general semiconductor material, and the price of the plastic is lower.

With the energy-saving lamp gap is still large

But over the years, OLED in the luminescent efficiency and service life has failed to form a strong market competitiveness, envisaged by industrialization and the research of OLED technology are also far from: the original plan to use polymer was replaced with a small organic molecule. As with inorganic semiconductor devices, OLED needs to be produced in a clean space, because pollution will shorten their service life. Even the smallest amount of dust falls on the semiconductor layer, which is 12 nanometers thick (sometimes only a few nanometers thick), and the structure of the OLED is more complex. Moreover, OLED must be stored in a completely vacuum and dry environment.

Despite the difficulties, the luminescent plastics in recent years have developed slowly: the average light power is 20Lm/W OLED (24Lm/W) as a halogen light source, high luminous efficiency, more than energy-saving lamps (65-85Lm/W), but the luminescence efficiency of OLED has been far more than incandescent lamps (14Lm/W). OLED is undoubtedly the development potential. 2009, the Dresden Institute of applied optical physics (IAPP) is the display of luminous efficiency of 90Lm/W light-emitting panel OLED. The EU's OLED100 initiative proposes the goal of bringing OLED to 100Lm/W luminous efficiency, 100 thousand hours of life, a size of $100 per square centimeter, and a cost of $100 per square meter. But for the sake of caution, the project did not mention the specific time limit.

OLED technology brings profit to enterprises

The technology has at least brought profits to Dresden's businesses. Novaled was founded in 2001 by the Dresden University Technology and the Fraunhofer Institute of optical Microsystems (IPMS), which began to be active in the market in the year of 2003. After just a few years of development, the company has a leading position in the OLED structure and material development. The company currently employs 110 people, plans to 2011 sales of EUR 20 million.

The success of the company is mainly due to the development of lighting materials in Dresden. Different from the simple model of the laboratory, the actual structure of the OLED is much more complex, there are many so-called functional layer and the luminescent layer mixed with various colors in the positive and negative electrodes, sometimes even up to 10 layers.

OLED market still need to wait and see

The colored pigments which are mixed in the OLED luminescent layer are composed of a carbon ring structure, and the color of the luminescent material is determined by the intermediate elements (such as iridium, germanium or platinum). Unlike inorganic LED, white light is produced by the mixing of basic colors, that is, even if the OLED emits white light, it also contains red, blue, and green light sources.

As a pioneer in OLED technology, Novaled has hundreds of innovative materials patents. Even so, there are a lot of research needs, such as the fine structure of the light-emitting layer and the blue dye used. Blue is very important for white OLED because it has the shortest service life. In addition to Dresden, other regions of the market competition is becoming increasingly fierce. PHILPS announced in early 2009 for the first time, the company's tailored LumibladeOLED market.

But so far, these OLED products are mainly for developers and designers, as well as in the exhibition and other occasions to attract people's attention. In early 2010 SIEMENS - OSRAM launched a light-emitting panel Orbeos, this honeycomb, only a diameter of 79 mm light emitting panel due to the limited number of sales, the price of each product reached $251. Novaled president believes that there is such a product to enter the market is very good, proved its feasibility, but it is only afraid of the pre industrial era.

Reinecke, a researcher at the Institute of Applied Optics physics at Dresden University, believes that the OLED market remains to be seen. He believes that although the technology is readily available, but at present the cost of large-scale production is too high, OLED market may also need to mature 5 years.