Efficient polarized blue electroluminescent device using oriented p-sexiphenyl thin film

Abstract Highly oriented p -sexiphenyl (6P) film was successfully prepared by epitaxial-growth on rubbed 6P film on hole-transporting poly(9,9 ′ -dioctylfluorene) (POF). Using the epitaxial-growth film of 6P, we prepared tri-layered device, ITO/POF/epitaxial-growth film of 6P/electron-transporting ozadiazole derivative (OXD7)/LiF/A1. The device with the epitaxial-growth film of 6P as emissive layer exhibited highly polarized and efficient blue electroluminescence (EL). EL peaking around 430 nm corresponded well to photoluminescence of 6P film. The maximum value of polarization ratio I p / I s of the blue EL was 37, where I p and I s are EL intensity parallel and perpendicular to the orientation direction, respectively. The values of maximum luminance L max and maximum current efficiency η max of the tri-layered device were enhanced comparing to those of a double-layered device ITO/6P/OXD7/LiF/Al; L max =146 cd m −2 and η max =0.41 cd A −1 for the tri-layered device whereas L max =32 cd m −2 and η max =0.07 cd A −1 for the double-layered device.