R2R processing of flexible small molecule OLEDs for lighting applications

While working prototypes of OLEDs for lighting have been released by different suppliers and are close to general market-availability, the race for the mainstream lighting technology of the next decades has started between OLEDs, inorganic LEDs, and the currently dominating fluorescent lamps. OLEDs have the potential to exceed the efficiency and lifetime standards that have already been set by the other technologies; however their latecomer status will require additional benefits to prepare the ground for a significant penetration into the lighting market. Here, light quality (color quality and tunability, glare-free lighting) and cost are the parameters where OLEDs may outperform the potential of the other technologies. In this context, roll-to-roll processing of small molecule OLEDs is seen as a promising approach, combining the advantages of the high-efficiency p-i-n OLED designs with high-throughput production on comparably low-cost flexible substrates, and could initiate completely new products with considerable commercial potential. The paper will comment on the current status of roll-to-roll-processing of small molecule p-i-n OLEDs on flexible substrates, including substrate smoothing, structuring, vacuum coating of OLEDs, up to flexible encapsulation.