Thermally activated delayed fluorescent phenothiazine–dibenzo[a,j]phenazine–phenothiazine triads exhibiting tricolor-changing mechanochromic luminescence

Okazaki, Masato; Takeda, Youhei; Data, Przemyslaw; Pander, Piotr; Higginbotham, Heather; Monkman, Andrew P.; Minakata, Satoshi

doi:10.1039/c6sc04863c

Thermally activated delayed fluorescent phenothiazine–dibenzo[a,j]phenazine–phenothiazine triads exhibiting tricolor-changing mechanochromic luminescence

Okazaki, Masato; Takeda, Youhei; Data, Przemyslaw; Pander, Piotr; Higginbotham, Heather; Monkman, Andrew P.; Minakata, Satoshi

Authors

Masato Okazaki

Youhei Takeda

Przemyslaw Data

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

Heather Higginbotham

Professor Andrew Monkman a.p.monkman@durham.ac.uk
Professor

Satoshi Minakata

Abstract

Novel U-shaped donor–acceptor–donor (D–A–D) π-conjugated multi-functional molecules comprising dibenzo[a,j]phenazine (DBPHZ) as an acceptor and phenothiazines (PTZ) as donors have been developed. Most importantly, the D–A–D compounds exhibit not only distinct tricolor-changeable mechanochromic luminescence (MCL) properties but also efficient thermally activated delayed fluorescence (TADF). Quantum chemical calculations, X-ray diffraction analysis, and systematic studies on the photophysical properties indicated that the “two-conformation-switchable” PTZ units play a highly important role in achieving multi-color-changing MCL. Time-resolved photophysical measurements revealed that the developed D–A–D compounds also exhibit efficient orange-TADF. Furthermore, organic light-emitting diode (OLED) devices fabricated with the new TADF emitters have achieved high external quantum efficiencies (EQEs) up to 16.8%, which significantly exceeds the theoretical maximum (∼5%) of conventional fluorescent emitters.

Citation

Okazaki, M., Takeda, Y., Data, P., Pander, P., Higginbotham, H., Monkman, A. P., & Minakata, S. (2017). Thermally activated delayed fluorescent phenothiazine–dibenzo[a,j]phenazine–phenothiazine triads exhibiting tricolor-changing mechanochromic luminescence. Chemical Science, 8(4), 2677-2686. https://doi.org/10.1039/c6sc04863c

Journal Article Type	Article
Acceptance Date	Jan 7, 2017
Online Publication Date	Jan 11, 2017
Publication Date	Apr 1, 2017
Deposit Date	May 16, 2017
Publicly Available Date	May 16, 2017
Journal	Chemical Science
Print ISSN	2041-6520
Electronic ISSN	2041-6539
Publisher	Royal Society of Chemistry
Peer Reviewed	Peer Reviewed
Volume	8
Issue	4
Pages	2677-2686
DOI	https://doi.org/10.1039/c6sc04863c