Enhanced light output in bilayer light-emitting diodes with film thickness variations

Jong Hyeok Park, Kwang Jik Lee, O. Ok Park, Jae Woong Yu, Young Chul Kim, Jai Kyeong Kim

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)


Electroluminescence (EL) and the dynamics of charge carrier recombination in the PVK/poly(9,9′-dihexylfluorene-2,7-divinylene-m-phenylenevinylene- stat-p-phenylenevinylene)(PDHFPPV) bilayer EL devices, which have various film thickness ratios, were studied. The indium-tinoxide (ITO)/(PVK/PDHFPPV bilayer)/Li:Al devices showed more enhanced color quality compared with those of single and blended devices. The current-voltage-luminescence characteristics of the devices, which have a different PVK/PDHFPPV thickness ratio, are systematically studied and compared with a best PVK:PDHFPPV blended device. The EL light output of bilayer devices can be improved remarkably by controlling PVK and PDHFPPV polymer thickness. The ITO/(PVK (60 nm)/PDHFPPV (50 nm) bilayer)/Li:Al device showed ∼50 times improved light output compared with that of best blended device.

Original languageEnglish
Pages (from-to)101-104
Number of pages4
JournalChemical Physics Letters
Issue number1-3
Publication statusPublished - 2004 Mar 1

Bibliographical note

Funding Information:
This research was performed with the financial support of the Center for Nanostructured Materials Technology under the 21st Century Frontier R&D Programs of the Ministry of Science and Technology, Korea. The authors also express their gratitude to the Center for Advanced Functional Polymers.

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry


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