A great deal of effort has been devoted to trying to produce low-cost organic light-emitting diodes (OLEDs) via printing processes—inkjet, screen, and gravure. So far, though, making these devices has demanded tightly controlled conditions (including artificial atmospheres).
Now, Andreas Sandström and collaborators at the Umea University Physics Department in Sweden and the Technical University of Denmark have flipped the switch on light-emitting electrochemical cells (LECs). These devices consist of a mobile-ion active layer sandwiched between a cathode-coated base layer and a semitransparent anode layer.
…The researchers are particularly enthusiastic about two points: first, the device is fabricated in open atmosphere. And second, the device operates even if the deposited layers are very uneven; it does not require the tight tolerances that OLEDs demand, and light emission remains highly uniform over the test device’s 300-square-millimeter surface.
Or, as they put it in their paper, “the fabrication yield of the roll-coated LECs is found to be very satisfying, primarily due to the fault-tolerant device geometry with a thick active layer and air-stable materials.”
As a bonus, because anode and cathode layers are transparent, the device shines from both its top and bottom surfaces.