Role of electron-electron interactions on spin effects in electron-hole recombination in organic light emitting diodes

Das, Mousumi and Ramasesha, S and Mazumdar, S (2005) Role of electron-electron interactions on spin effects in electron-hole recombination in organic light emitting diodes. In: Synthetic Metals, 155 (2). pp. 270-273.

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Abstract

We investigate the possibility that high-energy singlet and triplet excited states with large electron-hole separations are generated in electron-hole recombination process, over and above the lowest singlet and triplet excitons. Using a time-dependent calculation of the interchain/intermolecular charge-transfer within model Hamiltonians that explicitly include electron-electron interactions between the pi-electrons, we show that there occurs a bifurcation of the electron-hole recombination path in each of the two spin channels that leads to the generation of both the lowest energy exciton and a specific-high-energy charge-transfer state, with the matrix elements favoring the lowest energy exciton and the energy difference factor favoring the higher energy state, resulting in an enhancement of the singlet:triplet yield ratio above the value of 0.25 predicted from statistical considerations.

Item Type:	Journal Article
Publication:	Synthetic Metals
Publisher:	Elsevier Science BV
Additional Information:	Copyright for this article belongs to Elsevier.
Keywords:	Electroluminescence; Organic light emitting diodes; Electron-electron interactions; Model Hamiltonians
Department/Centre:	Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Date Deposited:	23 Jan 2006
Last Modified:	19 Sep 2010 04:23
URI:	http://eprints.iisc.ac.in/id/eprint/5189

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