Influence of ionizing dopants on charge transport in organic semiconductors

Antonio Abate, Daniel R. Staff, Derek J. Hollman, Henry J. Snaith, Alison B. Walker

Research output: Contribution to journalArticle

37 Citations (Scopus)

Abstract

Ionizing chemical dopants are widely used in organic semiconductors to enhance the charge transport properties by increasing the number of mobile charge carriers. However, together with mobile charges, chemical doping produces anion–cation pairs in the organic matrix. In this work we use experimental and computational analysis to study the influence of these ionic species on the charge transport. We show that the anion–cation pairs introduced upon doping have a detrimental, doping-level dependent effect on charge mobility. For doping levels of 0.02–0.05% molar ratio with respect to the molecular organic semiconductor, the increase in conductivity from the extra mobile charges is partially cancelled by a reduction in charge mobility from traps introduced by the anion–cation pairs. As the doping concentration increases, anion–cation pairs start to overlap, resulting in a comparatively smoother potential landscape, which increases the charge mobility to values closer to the undoped semiconductor. This result has a significant, practical impact, as it shows the need to dope at or slightly above a threshold level, which depends on the specific host-dopant combination.
Original languageEnglish
Pages (from-to)1132-1138
Number of pages7
JournalPhysical Chemistry Chemical Physics
Volume16
Issue number3
Early online date20 Nov 2013
DOIs
Publication statusPublished - 1 Jan 2014

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Semiconducting organic compounds
organic semiconductors
Charge transfer
Doping (additives)
anions
cations
Anions
Cations
charge carriers
transport properties
traps
Charge carriers
Transport properties
conductivity
thresholds
matrices
Semiconductor materials

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Influence of ionizing dopants on charge transport in organic semiconductors. / Abate, Antonio; Staff, Daniel R.; Hollman, Derek J.; Snaith, Henry J.; Walker, Alison B.

In: Physical Chemistry Chemical Physics , Vol. 16, No. 3, 01.01.2014, p. 1132-1138.

Research output: Contribution to journalArticle

Abate, Antonio ; Staff, Daniel R. ; Hollman, Derek J. ; Snaith, Henry J. ; Walker, Alison B. / Influence of ionizing dopants on charge transport in organic semiconductors. In: Physical Chemistry Chemical Physics . 2014 ; Vol. 16, No. 3. pp. 1132-1138.
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