Electronic Structure of Exciplexes and the Role of Local Triplet States on Efficiency of Thermally Activated Delayed Fluorescence

Chapran, Marian; Sahalianov, Ihor; Karaush-Karmazin, Nataliya N.; Wiosna-Salyga, Gabriela; Glowacki, Ireneusz; Luszczynska, Beata; Pander, Piotr; Baryshnikov, Glib V.

doi:10.1021/acsaelm.2c01518

Electronic Structure of Exciplexes and the Role of Local Triplet States on Efficiency of Thermally Activated Delayed Fluorescence

Chapran, Marian; Sahalianov, Ihor; Karaush-Karmazin, Nataliya N.; Wiosna-Salyga, Gabriela; Glowacki, Ireneusz; Luszczynska, Beata; Pander, Piotr; Baryshnikov, Glib V.

Authors

Marian Chapran

Ihor Sahalianov

Nataliya N. Karaush-Karmazin

Gabriela Wiosna-Salyga

Ireneusz Glowacki

Beata Luszczynska

Piotr Pander piotr.h.pander@durham.ac.uk
Academic Visitor

Glib V. Baryshnikov

Abstract

In this work, we present an investigation of the electronic states in a series of thermally activated delayed fluorescence (TADF) exciplexes formed with the popular electron-transport compound TpBpTa and hole-transporting TCTA, TAPC, TPD10, TPD, and NPB. We rationalize the photophysical behavior of exciplexes by using computational methods and demonstrate that the reason for the commonly observed temporal red shift in the time-resolved spectra is related to the distribution of molecular conformations, thus CT energy, in film. We also use spectrally resolved thermoluminescence (SRTL) measurements to give insight into the trapping phenomena in exciplex blends. The results demonstrate that trapped charge carriers in the majority of studied exciplexes recombine through the luminescent intermolecular CT state. In addition, we report OLED devices using the said exciplexes in the emissive layer. The best performance is obtained with the TCTA:TpBpTa and TAPC:TpBpTa exciplexes showing maximum external quantum efficiencies (EQEs) of 8.8% and 7.2%, respectively.

Citation

Chapran, M., Sahalianov, I., Karaush-Karmazin, N. N., Wiosna-Salyga, G., Glowacki, I., Luszczynska, B., …Baryshnikov, G. V. (2023). Electronic Structure of Exciplexes and the Role of Local Triplet States on Efficiency of Thermally Activated Delayed Fluorescence. ACS Applied Electronic Materials, 5(3), 1489-1501. https://doi.org/10.1021/acsaelm.2c01518

Journal Article Type	Article
Acceptance Date	Feb 7, 2023
Online Publication Date	Feb 20, 2023
Publication Date	2023
Deposit Date	Apr 27, 2023
Publicly Available Date	Apr 28, 2023
Journal	ACS Applied Electronic Materials
Print ISSN	2637-6113
Electronic ISSN	2637-6113
Publisher	American Chemical Society
Peer Reviewed	Peer Reviewed
Volume	5
Issue	3
Pages	1489-1501
DOI	https://doi.org/10.1021/acsaelm.2c01518