Simultaneous efficiency enhancement and self-cleaning effect of white organic light-emitting devices by flexible antireflective films

In this Letter, we report the improved light outcoupling efficiency of conventional white organic light-emitting devices (OLEDs) by a kind of multifunctional film with both antireflective and superhydrophobic ability. This film consisted of regular polydimethylsiloxane (PDMS) nanopillar arrays, which were readily batch produced by low-cost imprint lithography. The nanopillar arrays could effectively eliminate the light total reflection and enhance the device efficiency of OLEDs by producing the gradual refractive index due to the decreasing material density from glass to air. Moreover, owing to its superhydrophobicity (contact angle similar to 151 degrees), the antireflective film exhibited self-cleaning ability, which was beneficial for keeping the OLEDs substrate clean and ensure the high efficiency of OLEDs. This method is simple, cost-effective, and reproducible. The OLEDs showed an efficiency enhancement of 25% with the multifunctional film. (C) 2011 Optical Society of Americ