Transient analysis of organic electrophosphorescence. II. Transient analysis of triplet-triplet annihilation

• Baldo, Marc.A.

  Center for Photonics and Optoelectronic Materials (POEM), Department of Electrical Engineering and the Princeton Materials Institute, Princeton University

• 安達, 千波矢

  プリンストン大学

• Forrest, Stephen R.

  Center for Photonics and Optoelectronic Materials (POEM), Department of Electrical Engineering and the Princeton Materials Institute, Princeton University

抄録

In the preceding paper, Paper I [Phys. Rev. B 62, 10 958 (2000)], we studied the formation and diffusion of excitons in several phosphorescent guest-host molecular organic systems. In this paper, we demonstrate that the observed decrease in electrophosphorescent intensity in organic light-emitting devices at high current densities [M. A. Baldo et al., Nature 395, 151 (1998)] is principally due to triplet-triplet annihilation. Using parameters extracted from transient phosphorescent decays, we model the quantum efficiency versus current characteristics of electrophosphorescent devices. It is found that the increase in luminance observed for phosphors with short excited-state lifetimes is due primarily to reduced triplet-triplet annihilation. We also derive an expression for a limiting current density (J0) above which triplet-triplet annihilation dominates. The expression for J0 allows us to establish the criteria for identifying useful phosphors and to assist in the optimized design of electrophosphorescent molecules and device structures.

収録刊行物

• Physical Review B

  Physical Review B 62 (16), 10967-10977, 2000-10-15

  The American Physical Society

キーワード

• organic electrophosphorescence
• triplet-triplet annihilation
• electroluminescent

詳細情報

• CRID: 1050017057728372480
• NII論文ID: 120002893737
• NII書誌ID: AA11187113
• HANDLE: 2324/19445
• 本文言語コード: en
• 資料種別: journal article
• データソース種別:
  • IRDB
  • CiNii Articles