KCS

A new high-efficiency polymer based multi-layer photonic crystal organic light emitting diode (PoMPC)-OLED has fabricated using a low pressure and room temperature ultraviolet nanoimprint lithography (UV-NIL) process. The anode, organic layers and metallic layers are deposited directly onto the PC structures. The PC effect on the substrate, anode and organic layers and the Bragg diffraction on the patterned metal mirror results in a high efficiency even with a sub-100 nm pillar height. A patterned anode structure resulted in a decrease of the operating voltage. A PoMPC-OLED with a pillar height of 50 nm was fabricated showing a power efficiency 93% higher than a reference OLED without a PC structure. In a PoMPC-OLED, when the pillar height is below a certain value, deposition of the anode and the organic layers can be achieved without sharp edges which are the source of electrical leakage. In addition, as no additional planarization process is necessary before the deposition of the anode, it is much easier to control the particle contamination problem. Much better OLED performance can be obtained by optimizing the pillar height of the PC structure. A novel UV-NIL that employs photosensitive titanium (IV) di-n-butoxide bis(2-ethylhexanoate) is presented for the fabrication of well-ordered titanium dioxide (TiO2) nanostructures at room temperature. This approach allows direct fabrication of TiO2 nanopatterns with lines down to sub-50 nm in width and three-dimensional TiO2 hybrid micro/nano-patterns without observable defects for use in applications where ordered surface nanostructures are required, such as photovoltaics, photonics, and optical waveguides.