A team of scientists from Singapore's Institute of Materials Research and Engineering (IMRE) has developed a new patented film that is claimed to have the highest reported water vapor barrier performance to date, as tested by the UK Centre for Process Innovation.
IMRE says that its barrier technology, which protects sensitive devices like OLEDs and solar cells from moisture, is 1,000 times more effective than any other technology available in the market, opening up new opportunities for the plastic electronics sector.
According to IMRE, current commercially available films have a barrier property or water vapor transmission rate of about 10-3 g/m2 per day, at 25°C and 90% relative humidity (RH). The ideal film for organic devices requires a barrier property of better than 10-6 g/m2 per day at 39°C and 90% RH.
Current barriers are made from a series of alternating polymer and metal oxide layers that make up the plastic. This staggers adjacent “pinholes” (natural defects in the layers), thus slowing the passage of moisture and air through them.
IMRE has resolved the “pore effect” (in which water and oxygen gradually seeps through) in multi-layered barrier stacks. The effectiveness of IMRE's barrier technology lies in the unique barrier stack design, where nanoparticles are used when layering the barrier films. The design has a special layer of nanoparticles between the “pinhole” oxide layers. The nanoparticles “plug” the gaps and cracks in the oxide layer thus making the layer more impermeable. In addition to sealing defects in the oxide barrier film, the nanoparticles absorb and retain the water and oxygen molecules. This concept helps reduce the number of barrier stacks to just two or three.
Using this concept, IMRE has developed ultra high barrier plastic substrates (barrier properties < 10-6 g/m2 per day) for high barrier applications. Calcium test results show that there is no calcium oxidation up to 2300 hours at 60°C and 90% RH.
A key element of developing the barrier technology has been the availability of an appropriate testing methodology. The IMRE project team has developed a highly sensitive moisture and oxygen permeation measurement system in tandem with the development of the film which can measure permeation of less than 10-8 g/m2 per day.
IMRE has already signed agreements with a number of companies to advance the technology into the commercial domain. This includes a collaboration agreement with G24Innovations, a thin film solar cell manufacturer to look into developing the films for use in solar cells. IMRE has also signed a commercialization agreement with KISCO to commercialize and market the barrier films in the Asia Pacific region.
Boon Swan Foo, executive chairman of Exploit Technologies (the strategic marketing and commercialisation arm of A*STAR) says, "Exploit Technologies sees commercial potential in IMRE's breakthrough barrier film technology. It has excellent promise for enabling the fast growing plastic electronics industry. We want to take this technology from the lab to the market."
The Institute of Materials Research and Engineering (IMRE) is a materials research institute of the Singapore Agency for Science, Technology and Research (A*STAR).
