Publication details for Professor Andy MonkmanOkazaki, Masato, Takeda, Youhei, Data, Przemyslaw, Pander, Piotr, Higginbotham, Heather, Monkman, Andrew P. & Minakata, Satoshi (2017). Thermally activated delayed fluorescent phenothiazine–dibenzo[a,j]phenazine–phenothiazine triads exhibiting tricolor-changing mechanochromic luminescence. Chemical Science 8(4): 2677-2686.
- Publication type: Journal Article
- ISSN/ISBN: 2041-6520 (print), 2041-6539 (electronic)
- DOI: 10.1039/C6SC04863C
- Further publication details on publisher web site
- Durham Research Online (DRO) - may include full text
Author(s) from Durham
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.