抄録
燐光型有機EL素子は三重項からの発光を用いることがで、緑色や赤色で高い発光効率が実現されているが、短波長領域では未だ十分な特性が得られていない。短波長領域で十分な特性を得ることは次世代ディスプレイや照明に有用であり、表面プラズモン効果による発光効率向上の可能性を調べた。発光層全面にCBP: Ir(ppy)_3を用いた素子と発光層がCBP: Ir(ppy)_3/CBPから成る2種類の燐光型有機EL素子で、フォト・ルミネッセンスとエレクトロ・ルミネッセンスのスペクトル測定を行った。後者のCBP: Ir(ppy)_3/CBP素子では430nmでプラズモンからの発光と考えられるCBP層からの発光が見られたが、前者のCBP: Ir(ppy)_3ではそのような発光は見られなかった。また、プラズモン発光のピーク波長はプラズマ波長よりも長波長側にあった。
Phosphorescent organic devices use light emitted from the relaxation of triplet excitons, and high luminous efficiencies have been obtained in green and red devices. Achieving high luminous efficiency in the short wavelength region, which has not yet been attained, is critical to organic EL-used displays and lighting. We have examined the possibility of improving the luminous efficiency through the surface plasmon. We measured the photoluminescence and electroluminescence spectra for two kinds of phosphorescent organic devices. One of the devices used CBP: Ir(ppy)_3 and the other used CBP: Ir(ppy)_3/CBP as the emission layer. Light emission of around 430 nm, which was considered to originate from the surface plasmon, was observed only in the CBP: Ir(ppy)_3/CBP devices. It didn't, however, appear in the CBP: Ir(ppy)_3 devices. It was found that the wavelength of 430 nm was situated at a wavelength longer than the plasma wavelength.
