Stable and efficient blue fluorescent organic light-emitting diode by blade coating with or without electron-transport layer

Lan Sheng Yang, Hsin-Fei Meng*, Yu Fan Chang, Cheng Hsin Lien, Hsiao-Wen Zan, Sheng Fu Horng, Lian Duan, Yong Qiu

*Corresponding author for this work

Research output: Contribution to journalArticle

8 Scopus citations

Abstract

Multi-layer small-molecule blue fluorescent organic light-emitting diode (OLED) is fabricated by blade coating. The emission layer is based on a mixed host of 1-(7-(9,9′-bianthracen-10-yl)-9,9-dioctyl-9H-fluoren-2-yl)pyrene (PT-404) and electron-transport material 2,7-Bis(diphenylphosphoryl)-9,9′ -spirobifluorene (SPPO13), and the blue guest emitter is 4-4′-(1E,1′E)-2,2′-(naphthalene-2,6-diyl)bis(ethane-2,1-diyl)bis(N,N-bis(4-hexyl- Phenyl) aniline) (Blue D). A hole-transport layer of Poly-(9, 9-dioctylfluorenyl-2, 7-diyl)-co-(4, 4-(N-(4-sec-butylphenyl)) diphenylamine) (TFB) is added on top of PEDOT: PSS anode. The electrons are blocked away from TFB by a layer of pure host emission layer of PT-404 between TFB and the mixed –host emission layer. For the device with the electron transport layer of Tris(8-hydroxyquinolinato)aluminum (Alq3) blade-coated over the emission layer the efficiency and lifetime at initial brightness of 500 cd m−2 are 7.5 cd A−1 and 150 h for Alq3/CsF/Al cathode. When the Alq3/CsF/Al is replaced by simply CsF/Al over the mixed-host emission layer the efficiency and lifetime are 6.4 cd A−1 and 300 h (2 times longer than that of the Alq3/CsF/Al cathode). The lifetime depends on the electron-hole balance tuned by the mixed-host blending ratio as well as the electron injection from the cathode. This work shows good stability is possible for all-solution-processed blue OLED.

Original languageEnglish
Pages (from-to)6-15
Number of pages10
JournalOrganic Electronics
Volume51
DOIs
StatePublished - 1 Dec 2017

Keywords

  • Blade coating
  • Double emitting layers
  • Lifetime
  • Mixed host
  • Organic light-emitting diode
  • Solution-processed

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