Triplet energy transfer in conjugated polymers. I. Experimental investigation of a weakly disordered compound

Lekshmi Sudha Devi*, Mohammad K. Al-Suti, Carsten Dosche, Muhammad S. Khan, Richard H. Friend, Anna Köhler

*Corresponding author for this work

Research output: Contribution to journalArticle

53 Citations (Scopus)

Abstract

Efficient triplet exciton emission has allowed improved operation of organic light-emitting diodes (LEDs). To enhance the device performance, it is necessary to understand what governs the motion of triplet excitons through the organic semiconductor. Here, we have investigated triplet diffusion using a model compound that has weak energetic disorder. The Dexter-type triplet energy transfer is found to be thermally activated down to a transition temperature TT, below which the transfer rate is only weakly temperature dependent. We show that above the transition temperature, Dexter energy transfer can be described within the framework of Marcus theory. We suggest that below TT, the nature of the transfer changes from phonon-assisted hopping to quantum-mechanical tunneling. The lower electron-phonon coupling and higher electronic coupling in the polymer compared to the monomer results in an enhanced triplet diffusion rate.

Original languageEnglish
Article number045210
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume78
Issue number4
DOIs
Publication statusPublished - Jul 25 2008

ASJC Scopus subject areas

  • Condensed Matter Physics

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