Pentacene Excitons In Strong Electric Fields

Keywords

density functional calculations; electroluminescence; excitons; pentacene; scanning probe microscopy

Abstract

Electroluminescence spectroscopy of organic semiconductors in the junction of a scanning tunneling microscope (STM) provides access to the polarizability of neutral excited states in a well-characterized molecular geometry. We study the Stark shift of the self-trapped lowest singlet exciton at 1.6 eV in a pentacene nanocrystal. Combination of density functional theory (DFT) and time-dependent DFT (TDDFT) with experiment allows for assignment of the observation to a charge-transfer (CT) exciton. Its charge separation is perpendicular to the applied field, as the measured polarizability is moderate and the electric field in the STM junction is strong enough to dissociate a CT exciton polarized parallel to the applied field. The calculated electric-field-induced anisotropy of the exciton potential energy surface will also be of relevance to photovoltaic applications.

Publication Date

2-5-2018

Publication Title

ChemPhysChem

Volume

19

Issue

3

Number of Pages

277-283

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1002/cphc.201701174

Socpus ID

85040695181 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/85040695181

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