Electron-hole capture suppression and ultraviolet emission in conjugated polymers under high electric fields

En Shi Chen, Sheng Hsuan Yeh, Hsin-Fei Meng*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

The probability for the Coulomb capture of an electron-hole pair to form an exciton in conjugated polymers is found to be significantly suppressed under high electric field, which is usually required for electroluminescence due to the low mobility. The Coulomb capture is a continuous descent of electronic energy through cascade emission of phonons, and the high field prevents this descent by heating up the carriers. On the other hand, ultraviolet emission through direct interband transition is found to be much less affected by the field, and becomes the dominant radiative decay channel for field beyond 108 V/m. Combined with impact ionization, our model provides a complete quantitative explanation of the peculiar high-field behaviors of the visible emission ultraviolet emission, and current observed in conjugated polymer both before and after the avalanche breakdown.

Original languageEnglish
Article number235206
Pages (from-to)1-11
Number of pages11
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume65
Issue number23
DOIs
StatePublished - 15 Jun 2002

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