Planarization of nanopatterned substrates using solution process to enhance outcoupling efficiency of organic light emitting diodes

Large enhancement of light extraction efficiency of an organic light emitting diode and low leakage current are achieved by adopting planarized nanopatterned substrates fabricated using solution processes. Hexagonal pillars are imprinted using ultraviolet nano-imprint lithography (UV-NIL) technique and planarized using sol–gel processed titanium oxide (TiO2) followed by pressing with polydimethylsiloxane. TiO2 has much higher refractive index than pillars and is transparent in visible spectrum. This planarized substrate has been successfully integrated with organic light emitting diodes (OLEDs) and the resulting light outcoupling efficiency is enhanced by 58% compared to that of the conventional OLEDs.