title: MgO nano-facet embedded silver-based dielectric/metal/dielectric transparent electrode.
abstract: We replace Indium Tin Oxide (ITO) with an MgO nano-facet Embedded WO(3)/Ag/WO(3)(WAW) multilayer for electrodes of high efficiency OLEDs. WAW shows higher values for transmittance (93%) and conductivity (1.3×10(5) S/cm) than those of ITO. Moreover, WAW shows higher transmittance (92.5%) than that of ITO (86.4%) in the blue region (<500 nm). However, due to the large difference in refractive indices (n) of glass (n=1.55) and WO(3) (n=1.95), the incident light has a small critical angle (52°). Thus, the generated light is confined by the glass/WAW interface, resulting in low light outcoupling efficiency (~20%). This can be enhanced by using a nano-facet structured MgO (n=1.73) layer and a ZrO(2) (n=1.84) layer as a graded index layer. Using these optimized electrodes, ITO-free, OLEDs with various emission wavelengths have been produced. The luminance of OLEDs using MgO/ZrO(2)/WAW layers is enhanced by 24% compared to that of devices with ITO.
authors.affiliation: Department of Materials Science and Engineering, Division of Advanced Materials Science, Pohang University of Science and Technology (POSTECH), Pohang, Gyeongbuk, South Korea.
authors.forename: Sungjun
authors.initials: S
authors.lastname: Kim
authors.forename: Hak Ki
authors.initials: HK
authors.lastname: Yu
authors.forename: Kihyon
authors.initials: K
authors.lastname: Hong
authors.forename: Kisoo
authors.initials: K
authors.lastname: Kim
authors.forename: Jun Ho
authors.initials: JH
authors.lastname: Son
authors.forename: Illhwan
authors.initials: I
authors.lastname: Lee
authors.forename: Kyoung-Bo
authors.initials: KB
authors.lastname: Kim
authors.forename: Tae-Yeob
authors.initials: TY
authors.lastname: Kim
authors.forename: Jong-Lam
authors.initials: JL
authors.lastname: Lee
mesh_terms: D004553:Electric Conductivity; D004566:Electrodes; D005898:Glass / Q000737:chemistry; D008277:Magnesium Oxide / Q000737:chemistry*; D036103:Nanotechnology / Q000295:instrumentation / Q000379:methods*; D055096:Optical Devices; D010087:Oxides / Q000737:chemistry; D012031:Refractometry / Q000295:instrumentation / Q000379:methods*; D012834:Silver / Q000737:chemistry*; D014414:Tungsten / Q000737:chemistry; D015040:Zirconium / Q000737:chemistry
chemical_list: D010087:Oxides; D008277:Magnesium Oxide; D012834:Silver; C511604:tungsten oxide; D015040:Zirconium; C028541:zirconium oxide; D014414:Tungsten