The triplet-triplet annihilation process of triplet to singlet excitons to fluorescence in polymer light-emitting diodes

Nidya Chitraningrum, Ting Yi Chu, Ping Tsung Huang, Ten Chin Wen, Tzung Fang Guo

Research output: Contribution to journalArticlepeer-review

17 Citations (Scopus)

Abstract

We investigate the possible triplet-triplet annihilation (TTA) process involving the conversion of triplet to singlet excitons by measuring the magnetoconductance (MC) and magnetoelectroluminescence (MEL) responses of the phenyl-substituted poly(p-phenylene vinylene) copolymer (super yellow, SY-PPV)-based polymer light-emitting diodes (PLEDs). Under low applied magnetic field (< 200 Oe), both the positive MC and MEL are observed. However, at high magnetic field (> 200 Oe), the magnitude of MEL decreases as a consequence of the decreased TTA process of triplet to singlet excitons and the fluorescence. We increase the concentration and lifetime of the triplet excitons by biasing SY-PPV-based PLEDs at the high current density and in the low temperature regime, respectively, to verify the TTA process. We observe an evident drop in MEL magnitude at 1000 Oe for the device constantly biased with 166.67 mA/cm2 at 100 K, which is correlated with the reduced TTA process under the high magnetic field. The TTA process may harvest the energy from triplet to singlet excitons in SY-PPY active layer and in part contribute the emission to fluorescence in PLEDs especially in the high current density regime.

Original languageEnglish
Pages (from-to)505-510
Number of pages6
JournalOrganic Electronics
Volume62
DOIs
Publication statusPublished - 2018 Nov

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • General Chemistry
  • Condensed Matter Physics
  • Materials Chemistry
  • Electrical and Electronic Engineering

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