Skip to main content

Research Repository

Advanced Search

Rational Design of TADF Polymers Using a Donor–Acceptor Monomer with Enhanced TADF Efficiency Induced by the Energy Alignment of Charge Transfer and Local Triplet Excited States

Nobuyasu, Roberto S.; Ren, Zhongjie; Griffiths, Gareth C.; Batsanov, Andrei S.; Data, Przemyslaw; Yan, Shouke; Monkman, Andrew P.; Bryce, Martin R.; Dias, Fernando B.

Rational Design of TADF Polymers Using a Donor–Acceptor Monomer with Enhanced TADF Efficiency Induced by the Energy Alignment of Charge Transfer and Local Triplet Excited States Thumbnail


Authors

Roberto S. Nobuyasu

Zhongjie Ren

Gareth C. Griffiths

Andrei S. Batsanov

Przemyslaw Data

Shouke Yan



Abstract

The photophysics of thermally activated delayed fluorescence (TADF) in phenothiazine-dibenzothiophene-S,S-dioxide (PTZ-DBTO2) molecule is investigated in detail. First, it is shown that the proximity of local triplet excited states (3LE), e.g., 3D or 3A, above or below the DA charge transfer states (CT) is crucial for the efficiency of the TADF mechanism in PTZ-DBTO2. This TADF emitter is then used as a monomer unit to design polymer materials with efficient TADF. The reverse intersystem crossing mechanism (RISC) that supports TADF is able to compete with internal conversion and triplet–triplet annihilation (TTA) in the polymer chains and generates efficient TADF emission in the polymer pristine films. Prototype devices with PTZ-DBTO2 dispersed in 4,4′-bis(N-carbazolyl)-2,2′-biphenyl (CBP) host give excellent performance with EQE of ≈22% at low luminance (<100 cd m−2), for 100 cd m−2 the EQE is 19.4%. In the case of solution processed devices, using the novel TADF polymers, the performance is much lower, EQE ≈3.5% at 100 cd m−2, which is still the highest value for a polymer TADF system at useful brightness, yet reported. This results from a combination of weak charge transport properties in these materials and device fabrication methods that require further improvement. Nevertheless, these results pave the way to explore TADF in polymer light emitting diodes (PLEDs), using less costly deposition methods, such as spin-coating and inkjet printing, which are more appropriate for large area deposition.

Citation

Nobuyasu, R. S., Ren, Z., Griffiths, G. C., Batsanov, A. S., Data, P., Yan, S., …Dias, F. B. (2016). Rational Design of TADF Polymers Using a Donor–Acceptor Monomer with Enhanced TADF Efficiency Induced by the Energy Alignment of Charge Transfer and Local Triplet Excited States. Advanced Optical Materials, 4(4), 597-607. https://doi.org/10.1002/adom.201500689

Journal Article Type Article
Acceptance Date Jan 12, 2016
Online Publication Date Jan 12, 2016
Publication Date Apr 1, 2016
Deposit Date Jan 12, 2016
Publicly Available Date Jan 12, 2017
Journal Advanced Optical Materials
Publisher Wiley
Peer Reviewed Peer Reviewed
Volume 4
Issue 4
Pages 597-607
DOI https://doi.org/10.1002/adom.201500689
Keywords Conjugated polymers, dibenzothiophene-S,S-dioxide, OLEDs, Phenothiazine, TADF.
Public URL https://durham-repository.worktribe.com/output/1422655

Files

Accepted Journal Article (1.4 Mb)
PDF

Copyright Statement
This is the peer reviewed version of the following article: Nobuyasu, R. S., Ren, Z., Griffiths, G. C., Batsanov, A. S., Data, P., Yan, S., Monkman, A. P., Bryce, M. R. and Dias, F. B. (2016), Rational Design of TADF Polymers Using a Donor–Acceptor Monomer with Enhanced TADF Efficiency Induced by the Energy Alignment of Charge Transfer and Local Triplet Excited States. Advanced Optical Materials, 4(4): 597-607 which has been published in final form at http://dx.doi.org/10.1002/adom.201500689. This article may be used for non-commercial purposes in accordance With Wiley-VCH Terms and Conditions for self-archiving.






You might also like



Downloadable Citations