LONDON – Cambrios Technologies Corp. (Sunnyvale, Calif.) has teamed up with Novaled AG (Dresden, Germany) to create a gridless 10-centimeter by 10-centimeter OLED lighting tile.
The two companies claimed that the combination of Novaleds' high performance organic light emitter materials and Cambrios' silver nanowire material is a breakthrough for large-area OLED lighting.
Conventional OLED tiles use indium tin oxide (ITO) as a transparent conductor however due to the limited conductivity of ITO – 20 ohms per square on glass and 50 to 100 ohms per square on flexible plastic film – the voltage drops significantly over lengths larger than 2 centimeters. Up until now the solution has been to include metal grids on top of the ITO to prevent gradients in the light emission caused by the voltage drop, but with grid showing as a shadow.
Novaled has used the Cambrios ClearOhm coating as alternative to the ITO-plus-metal combination. ClearOhm coatings can have a resistance as low as 5 ohms per square with greater than 90 percent light transmission independent on the carrier substrate. In addition the ClearOhm offers the potential for a cost reduction compared with ITO, the companies said.
Cambrios has demonstrated a 5 centimeter by 5 centimeter OLED lighting tile with efficiencies greater than 40 lumens per watt made using ClearOhm electrodes. The development of a 10 centimeter by 10 centimeter tile is expected to the standard commercial size of tile.
"With this approach manufacturers can produce high-performance, long lifetime OLED lighting tiles in high volumes at affordable costs," said Sven Murano, Novaled's vice president of project management, in a statement.