Materials science: Light on a roll

The creation of flexible, large-area light-emitting devices using roll-coating equipment is reported in this week’s Nature Communications. The devices are produced in an uninterrupted fashion in air, presenting a promising alternative to organic LEDs.

Organic materials can be used for a wide range of flexible electronic devices, including LEDs. However, these devices are very sensitive to the material properties, requiring a well-controlled layer thickness, and their fabrication currently takes place under vacuum, which makes them more costly and challenging to produce. An alternative is the light-emitting electrochemical cell (LEC), which is also formed from organic compounds, but without the sensitivity to imperfections of LEDs. Ludvig Edman and colleagues now produce LECs using uninterrupted roll-coating techniques in ambient conditions, allowing for large area and flexible light-emitting devices. The individual layers of the LEC are highly uneven - which would not be tolerated for LEDs - but the device performance is still high. They also show long-term stability, making them viable for low-cost, fault-tolerant production.