EPLED: new highly flexible polymer based LEC device with elastic transparent silver-nanowires electodes

Update: It turns out that this device is actually a polymer LEC device and not an OLED.

Researchers from the University of California, Los Angeles (UCLA) developed transparent elastic silver-nanowire based electrodes that enabled them to create a polymer based elastic LEC device that can be repeatedly stretched, folded and twisted (at room temperature) without effecting its shape and lighting properties. They call the new device EPLED (elastomeric polymer light-emitting device) and they managed to fabricate a 5x5 pixel Passive Matrix one:

The EPLED is the whole device, and it include electrodes made from a rubbery polymer with the silver nanowires embedded in it and a polymer LEC. The EPLED can still emit light even when exposed to strains as large as 120% and can survive repeated continuous stretching cycles. The researchers say that their solution-based fabrication process, used to create the prototype above, is scalable.

The EPLED prototype still continued to work at a high efficiency ever after 1,000 stretches and after extending it to 30% beyond its original shape and size. In a different test, they stretched it to more than twice its original size and it was still working. It can also be folded 180 degrees or twisted in multiple directions.

The researchers say that their new electrodes feature a high visual transparency, good surface electrical conductivity, high stretchability and high surface smoothness.

LEC and not OLED

When I first posted and read the news from UCLA, I thought this was an OLED (P-OLED) device. But this is actually a LEC device and not an OLED. The researchers explain that they chose P-LEC (polymer-LEC) device architecture and not OLED because it's simpler, there's no need for specific electrode workfunctions for charge injection and it has a straightforward fabrication process, compatible with conventional polymer processing technique.

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Posted: Sep 29,2013 by Ron Mertens