Output power enhancement of white organic light-emitting diodes via a nanopatterned substrate generated by a monolayer of nanospheres

In this work, the output power enhancement of the white light organic light emitting diode devices (OLEDs) is demonstrated on a patterned indium tin oxide substrate (PIS) prepared via etching self-assembled monolayer SiO₂ spheres as the hard mask. The finite difference method calculation, finite difference time domain calculation, and experimental results were performed and revealed that the smaller period of the PIS OLEDs will have better performance. At a constant current density of 20 mA/cm², the operating voltage of the PIS-OLEDs with a structural period of 300 nm (PIS-300) is reduced 36% compared with that of the planar OLEDs. In addition, at the luminance of 5000 cd/m², the luminous efficiency and external quantum efficiency of PIS-300 OLEDs are enhanced 228% and 58%, respectively.