Skip to main content

Research Repository

Advanced Search

Determination of standard redox rate constants of OLED active compounds by electrochemical impedance spectroscopy

Chulkin, Pavel; Lapkowski, Mieczyslaw; Bryce, Martin R.; Santos, Jose; Data, Przemyslaw

Determination of standard redox rate constants of OLED active compounds by electrochemical impedance spectroscopy Thumbnail


Authors

Pavel Chulkin

Mieczyslaw Lapkowski

Jose Santos

Przemyslaw Data



Abstract

A number of commercial organic compounds (m-MTDATA, PBD, CBP, TAPC, NPB, TPBi, etc) as well as several donor-acceptor-donor (D-A-D) compounds were investigated by cyclic voltammetry and electrochemical impedance spectroscopy. The compounds were chosen as they are promising components of small-molecule-based high efficiency Thermally Activated Delayed Fluorescence (TADF) emitters in Organic Light Emitting Diodes (OLEDs). Electrochemical impedance spectra of a Pt electrode in CH2Cl2 solutions containing the investigated compound and Bu4NBF4 as the electrolyte were obtained and analyzed by electrochemical electrical circuit methods. Charge transfer resistance, double layer capacitance, Warburg constant and other parameters were determined and represented as a function of the potential. Analysis of charge transfer resistance as a function of potential allowed an estimation of standard redox rate constants for the compounds' oxidation and reduction processes. Two main features concerning the redox reaction rates of OLED-active compounds were revealed: (i) the oxidation and reduction rates of ambipolar compounds, i.e. containing both donor and acceptor parts, were found to be much higher than those of unipolar donor-only and acceptor-only molecules; (ii) the relationship between the oxidation and reduction rate constants was shown to be related to the compounds' conductivity type in the solid state.

Citation

Chulkin, P., Lapkowski, M., Bryce, M. R., Santos, J., & Data, P. (2017). Determination of standard redox rate constants of OLED active compounds by electrochemical impedance spectroscopy. Electrochimica Acta, 258, 1160-1172. https://doi.org/10.1016/j.electacta.2017.11.171

Journal Article Type Article
Acceptance Date Nov 23, 2017
Online Publication Date Nov 24, 2017
Publication Date Dec 20, 2017
Deposit Date Dec 4, 2017
Publicly Available Date Mar 28, 2024
Journal Electrochimica Acta
Print ISSN 0013-4686
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 258
Pages 1160-1172
DOI https://doi.org/10.1016/j.electacta.2017.11.171

Files






You might also like



Downloadable Citations