Phosphorescent iridium(III) cored dendrimers for light-emitting displays

J. C. Ribierre, S. V. Staton, P. L. Burn, I. D.W. Samuel

研究成果: ジャーナルへの寄稿会議記事査読

1 被引用数 (Scopus)

抄録

Solution-processable electrophosphorescent dendrimers are an emerging class of materials for highly efficient light-emitting diodes. Here, we report time-resolved photoluminescence measurements in a fac-tris(2-phenylpyridyl) iridium(III) [Ir(ppy)3]-cored dendrimer in neat film and blended into a 4,4'-bis(N-carbazolyl)biphenyl (CBP) host. Our results identify the existence of a photodegradation process that occurs in solution prior to processing, which significantly affects the photoluminescence kinetics of the films and leads to lower external quantum efficiencies of solution-processed phosphorescent dendrimer light-emitting displays. In parallel, we studied the triplet-triplet exciton annihilation processes in these materials from the photoluminescence decays measured at various excitation densities. From the values of the annihilation rates, we calculated the triplet exciton diffusion lengths and estimated the limiting current densities above which annihilation would dominate in phosphorescent dendrimer light-emitting devices. The results show that the triplet exciton diffusion length is small (<15 nm) in phosphorescent dendrimers and that exciton diffusion becomes still slower in the blends, which can be interpreted by the intermolecular spacing between the phosphorescent emitters being increased, thus reducing the annihilation rate.

本文言語英語
論文番号63330H
ジャーナルProceedings of SPIE - The International Society for Optical Engineering
6333
DOI
出版ステータス出版済み - 12月 1 2006
イベントOrganic Ligh Emitting Materials and Devices X - San Diego, CA, 米国
継続期間: 8月 13 20068月 16 2006

!!!All Science Journal Classification (ASJC) codes

  • 電子材料、光学材料、および磁性材料
  • 凝縮系物理学
  • コンピュータ サイエンスの応用
  • 応用数学
  • 電子工学および電気工学

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