Efficiency enhancement of organic light-emitting diodes via a self-assembled moth-eye nanopatterned hole-transporting layer.

A moth-eye nanopatterned hole-transporting layer (ME-HTL) is proposed to enhance the device efficiency of organic light-emitting diodes (OLEDs), which is fabricated via spontaneous phase separation during spin-coating between poly(N-vinylcarbazole) (PVK) and poly (9,9-dioctylfluorene) (PFO) induced by their surface energy difference. Meanwhile, film morphology characteristics confirm the conformal deposition of the following organic layers and metal electrode on the ME-HTL, indicating the extension of ME nanostructure over all layers in OLEDs. Finally, owning to the disruption of the internal waveguide light at the organic layer/anode interface and the suppression of surface plasmonic loss at organic layer/cathode interface, this device architecture obtained a current efficiency of 78.9 cd/A, with an enhancement factor of 40%. This approach takes the advantage of manufacturing compatibility on behalf of solution-process and thus can be a promising strategy to reduce the production cost of OLEDs.