Organic electronics — and particularly the printable form of this technology — has come closer to commercialization lately. Applications within reach are lighting and simple RFID-based applications such as trademark protection.
At industry meetings for the printable electronics industry in the past promises and projections used to take center stage since the technology was so much in its pre-infancy status that technologists only had very simple demonstrators to exhibit. At the LOPE-C event (Large-area, Organic and Printed Electronics Convention) that took place at the end of June in Frankfurt/Main (Germany) the situation was different. It became obvious that the technology is now on the verge of entering the commercial domain.
"There has been huge progress within the last year, in particular in materials, processing and manufacturing," said André Moreira, Investment Manager for BASF Venture Capital. Examples are electronic paper, OLED lighting, and smartcards where new trials have started lately, equipping smartcards with small organic displays for one-time password applications. "Mass production is around the corner," Moreira said.
Technological development has gained momentum as the supply chain ecosystem grows and supports collaboration. "Earlier, startups rushed to bring printable solutions to the market only to discover that they had to create most of the supporting technology themselves," said Alexei Andreev, managing director of venture capital company Harris & Harris Group.
This requirement to be vertically integrated and do many things in-house has stimulated the formation of an ecosystem that covers almost the entire value chain, Andreev observed. Large players have entered the market and provided missing pieces to the puzzle such as standard and customized production equipment and access to value chain partners. "This development has led to a connected printable electronics landscape instead of a collection of isolated companies and stand-alone projects," Andreev said.
As the infrastructure has matured the reach of printable electronics has increased. One of the technologies closest to market entry is OLED lighting with Philips, General Electric, and Osram as the major players.
General lighting could be the next killer application for organic LEDs. Source: Fraunhofer/Philips.
"Since the technological progress is advancing so well, it is becoming necessary to think about market positioning," said Bernhard Stapp, vice president and general manager OLED for solid-state lighting at the Siemens subsidiary Osram Semiconductors GmbH, adding that OLED is now mature enough for general lighting applications. Organic LEDs produce a warm light similar to the light of incandescent bulbs, at a yield of up to 2000 to 3000 candela per square meter.
But there still are challenges. The first one is cost. "Costs still are a barrier," Stapp acknowledged. And costs impact engineering trade-offs. Brightness, temperature and endurance are interdependent. The brighter an OLED light the more power it uses and the higher the temperature of the active components — and the lower its lifetime. "In operation, organic material should not exceed temperatures of 40 to 60 degrees Celsius," Stapp said. "Otherwise the thermal management becomes very difficult and the lifetime decreases."
There are other trade-offs to be considered. For instance, variable lighting characteristics are possible — at a price. "For variable light, the efforts required to drive the active diodes and to structure the circuitry increase dramatically", Stapp said. While it is feasible to reduce the size of the active areas and thus the pixels, smaller geometries eventually will require photo lithography processes much like conventional electronics. "Then the cost advantage is gone," Stapp said. "Color variation is 'nice to have' but it increases the complexity."
Another challenge is the high sensitivity of OLED materials to oxygen and water. The ideal moisture and oxygen barrier has yet to be found — glass is one candidate, but at the expense of flexibility, a feature required for some applications. And while in display applications, getter systems are wide spread, in lighting applications with a thickness of around one millimeter getter-based solutions are "a no-go" as Stapp puts it. The company says it has reached significant progress for cost-effective thin film encapsulation approaches during the past year.
