Issue 12, 2022

Photoluminescence and electrochemiluminescence of thermally activated delayed fluorescence (TADF) emitters containing diphenylphosphine chalcogenide-substituted carbazole donors

Abstract

Aiming to develop efficient blue-emitting thermally activated delayed fluorescence (TADF) compounds, we have designed and synthesized derivatives of the well-known sky-blue emitter 2CzPN that contain electron-accepting phosphine chalcogenide groups to stabilize the HOMO level relative to the pristine compound, thus increasing the HOMO–LUMO gap and blue-shifting the emission wavelength. By cyclic voltammetry, photophysical data and quantum-chemical calculations, it was found that polar solvents and matrices validated the proposed concept, but these trends were not recovered in non-polar media. The suitability of these 2CzPN derivatives in polar matrices for optoelectronic applications was explored with electrochemiluminescence (ECL) by measuring emission delays, radical stability, emission stabilities, emission efficiencies and emission spectra. Some of the 2CzPN derivatives showed an unprecedented delayed onset of the ECL, and delayed rising time to the ECL maximum, as well as long ECL emission decay. All of these mentioned delay times suggest that these luminophores primarily emit via organic long-persistent electrochemiluminescence (OLECL) mechanisms. The derivatization of the donor groups of the emitters affected both the radical stability and the predominant emission mechanism, providing important insight into their potential as emitters in solid-state electroluminescent devices.

Graphical abstract: Photoluminescence and electrochemiluminescence of thermally activated delayed fluorescence (TADF) emitters containing diphenylphosphine chalcogenide-substituted carbazole donors

Supplementary files

Article information

Article type
Paper
Submitted
26 noy 2021
Accepted
07 fev 2022
First published
08 fev 2022
This article is Open Access
Creative Commons BY license

J. Mater. Chem. C, 2022,10, 4646-4667

Photoluminescence and electrochemiluminescence of thermally activated delayed fluorescence (TADF) emitters containing diphenylphosphine chalcogenide-substituted carbazole donors

S. Kumar, P. Tourneur, J. R. Adsetts, M. Y. Wong, P. Rajamalli, D. Chen, R. Lazzaroni, P. Viville, D. B. Cordes, A. M. Z. Slawin, Y. Olivier, J. Cornil, Z. Ding and E. Zysman-Colman, J. Mater. Chem. C, 2022, 10, 4646 DOI: 10.1039/D1TC05696D

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