Triplet level-dependent photoluminescence and photoconduction properties of π-conjugated polymer thin films doped by iridium complexes

Jongdeok An, Jungyun Chang, Jungwook Han, Chan Im, Young Jun Yu, Dong Hoon Choi, Jung Il Jin, Tetsuro Majima

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8 Citations (Scopus)

Abstract

Triplet energy level-dependent decay pathways of excitons populated on iridium (Ir) complexes within π-conjugated polymeric matrices were studied by means of photoluminescence (PL) and photoconduction action spectroscopy. We chose a set of matrices, poly(9-vinylcarbazole) (PVK), poly[9,9-bis(2-ethylhexyl)fluorene-2,7-diyl] (PF2/6), poly [2-(5′-cyano-5′-methyl-hexyloxy)-1,4-phenylene] (CNPPP), and poly [2-(5′-cyano-5′-methyl-hexyloxy)-1,4-phenylene-co-pridine] (CNPPP-py10 and CNPPP-Py20), having triplet energy levels ranging from 2.2 up to 3.0 eV. As Ir-complex dopants, we selected three phosphorescent emitters, iridium(III)bis(2-(2′-benzothienyl) pyridinato-N-acetylacetonate) (Ir(btp)2acac), iridium(III)fac-tris(2-phenylpyridine) (Ir(ppy)3), and iridium(III)bis[(4,6-fluorophenyl)-pyridinato-N,C2′]picolinate (FIrpic), having triplet energy levels of 2.1, 2.5, and 2.7 eV, respectively. It was found that the triplet emission from the dopants, being populated via energy transfer from the matrices, was strongly dependent on the matching of triplet energy levels between matrix polymers and Ir-complexes. Photocurrent action spectra confirm effective exciton confinement at the dopants sites in the case of PVK matrix systems.

Original languageEnglish
Pages (from-to)371-376
Number of pages6
JournalJournal of Photochemistry and Photobiology A: Chemistry
Volume200
Issue number2-3
DOIs
Publication statusPublished - 2008 Dec 15

Bibliographical note

Funding Information:
This work was supported by the Seoul Research & Business Development (R & BD) Program (CR070048) and the Guest Associate Professor Program, Nanoscience and Nanotechnology Center, Institute of Scientific and Industrial Research (SANKEN), Osaka University. C.I. is indebted to Dr. Sergey Bagnich for fruitful discussions.

Keywords

  • Energy transfer
  • OLED
  • Phosphorescence
  • Photoluminescence
  • π-Conjugated polymer

ASJC Scopus subject areas

  • General Chemistry
  • General Chemical Engineering
  • General Physics and Astronomy

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