Direct observation of intersystem crossing in a thermally activated delayed fluorescence copper complex in the solid state

Bergmann, L., Hedley, G. J. , Baumann, T., Brase, S. and Samuel, I. D.W. (2016) Direct observation of intersystem crossing in a thermally activated delayed fluorescence copper complex in the solid state. Science Advances, 2(1), e1500889. (doi: 10.1126/sciadv.1500889) (PMID:26767194) (PMCID:PMC4705038)

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Abstract

Intersystem crossing in thermally activated delayed fluorescence (TADF) materials is an important process that controls the rate at which singlet states convert to triplets; however, measuring this directly in TADF materials is difficult. TADF is a significant emerging technology that enables the harvesting of triplets as well as singlet excited states for emission in organic light emitting diodes. We have observed the picosecond time-resolved photoluminescence of a highly luminescent, neutral copper(I) complex in the solid state that shows TADF. The time constant of intersystem crossing is measured to be 27 picoseconds. Subsequent overall reverse intersystem crossing is slow, leading to population equilibration and TADF with an average lifetime of 11.5 microseconds. These first measurements of intersystem crossing in the solid state in this class of mononuclear copper(I) complexes give a better understanding of the excited-state processes and mechanisms that ensure efficient TADF.

Item Type:Articles
Additional Information:We are grateful to CYNORA GmbH for financial support. This work was supported by the Engineering and Physical Sciences Research Council (grant no. EP/J009016/1) and by the European Union Seventh Framework Programme under grant agreement 321305. Support from the Transregio 88 (3MET, B2) (Deutsche Forschungsgemeinschaft) is acknowledged. Support from the Transregio 88 (3MET, B2) (Deutsche Forschungsgemeinschaft) is acknowledged.
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Hedley, Dr Gordon
Authors: Bergmann, L., Hedley, G. J., Baumann, T., Brase, S., and Samuel, I. D.W.
College/School:College of Science and Engineering > School of Chemistry
Journal Name:Science Advances
Publisher:American Association for the Advancement of Science
ISSN:2375-2548
ISSN (Online):2375-2548
Copyright Holders:Copyright © 2016 The Authors
First Published:First published in Science Direct 2(1):e1500889
Publisher Policy:Reproduced under a Creative Commons License

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