Novel fluorine-containing X-branched oligophenylenes: Structure-hole blocking property relationships

Zhong Hui Li*, Ka Lap Tong, Ricky M S WONG, Shu Kong SO

*Corresponding author for this work

Research output: Contribution to journalJournal articlepeer-review

12 Citations (Scopus)


Four fluorine-containing X-branched oligophenylenes, X-OPP(5)-Fn, n = 1,2,3 and X-OPP(5)-CF3, have been synthesized and studied as potential hole-blocking materials. These molecular materials exhibit a low HOMO energy level (ca. 6.5 eV) and a large energy gap (ca. 3.5 eV), indicating that they can be employed as effective hole-blockers in blue-emitting organic EL devices. Four-layer organic EL devices consisting of CuPc as a hole injection layer, α-NPD as a hole-transporting and emitting material, X-OPP(5)-Fn or X-OPP(5)-CF3 as a hole-blocker, and Alq3 as an electron-transporter sandwiched between indium tin oxide (ITO) and LiF/Al electrodes were fabricated, and their performance was examined and compared with the widely used holeblocker bathocuproine (BCP), the non-fluorine-containing X-branched analogue X-OPP(5)-H and the X-branched analogue with one less phenyl ring, X-OPP(3)-F2. The preliminary results show that these new molecular materials, especially X-OPP(5)-F2, are excellent hole-blockers for blue-emitting organic EL devices.

Original languageEnglish
Pages (from-to)765-772
Number of pages8
JournalJournal of Materials Chemistry
Issue number8
Publication statusPublished - 2006

Scopus Subject Areas

  • Chemistry(all)
  • Materials Chemistry


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