Donor and acceptor interlock by a planar indolo[3,2,1-jk]carbazole for a suppressed non-radiative mechanism in thermally activated delayed fluorescent emitters

2020 ◽  
Vol 8 (41) ◽  
pp. 14490-14498
Author(s):  
Vilas Venunath Patil ◽  
Yun Hwan Park ◽  
Kyung Hyung Lee ◽  
Jun Yeob Lee
Keyword(s):  
Molecular Structure ◽  
Delayed Fluorescence ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Donor And Acceptor ◽  
Donor Acceptor ◽  
Radiative Mechanism

In this work, we report a novel molecular structure of the thermally activated delayed fluorescence (TADF) emitters with the donor–acceptor structure interlocked by a planar indolo[3,2,1-jk]carbazole (ICz) unit to suppress a non-radiative mechanism.

scholarly journals A Novel Design Strategy for Suppressing Efficiency Roll-Off of Blue Thermally Activated Delayed Fluorescence Molecules through Donor–Acceptor Interlocking by C–C Bonds

Nanomaterials ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1735 ◽  
Author(s):  
Tae Hui Kwon ◽  
Soon Ok Jeon ◽  
Masaki Numata ◽  
Hasup Lee ◽  
Yeon Sook Chung ◽  
...  
Keyword(s):  
Energy Gap ◽  
Delayed Fluorescence ◽  
Triplet Energy ◽  
Design Synthesis ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Donor And Acceptor ◽  
Donor Acceptor ◽  
Display Performance ◽  
Commercial Applications

The short material lifetime of thermally activated delayed fluorescence (TADF) technology is a major obstacle to the development of economically feasible, highly efficient, and durable devices for commercial applications. TADF devices are also hampered by insufficient operational stability. In this paper, we report the design, synthesis, and evaluation of new TADF molecules possessing a sterically twisted skeleton by interlocking donor and acceptor moieties through a C–C bond. Compared to C–N-bond TADF molecules, such as CPT2, the C–C-bond TADF molecules showed a large dihedral angle increase by more than 30 times and a singlet–triplet energy-gap decrease to less than 0.22 eV because of the steric hindrance caused by the direct C–C bond connection. With the introduction of a dibenzofuran core structure, devices comprising BMK-T317 and BMK-T318 exhibited a magnificent display performance, especially their external quantum efficiencies, which were as high as 19.9% and 18.8%, respectively. Moreover, the efficiency roll-off of BMK-T318 improved significantly (26.7%). These results indicate that stability of the material can be expected through the reduction of their singlet–triplet splitting and the precise adjustment of dihedral angles between the donor–acceptor skeletons.

Novel thermally activated delayed fluorescence materials by high-throughput virtual screening: going beyond donor–acceptor design

2021 ◽  
Vol 9 (9) ◽  
pp. 3324-3333 ◽  
Author(s):  
Ke Zhao ◽  
Ömer H. Omar ◽  
Tahereh Nematiaram ◽  
Daniele Padula ◽  
Alessandro Troisi
Keyword(s):  
Virtual Screening ◽  
Quantum Chemistry ◽  
High Throughput ◽  
Delayed Fluorescence ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Quantum Chemistry Calculations ◽  
Donor Acceptor ◽  
Molecular Semiconductors ◽  
High Throughput Virtual Screening

125 potential TADF candidates are identified through quantum chemistry calculations of 700 molecules derived from a database of 40 000 molecular semiconductors. Most of them are new and some do not belong to the class of donor–acceptor molecules.

scholarly journals Regioisomeric Effect on the Excited-State Fate Leading to Room-Temperature Phosphorescence or Thermally Activated Delayed Fluorescence in a Dibenzophenazine-Cored Donor–Acceptor–Donor System

2021 ◽  
Author(s):  
Takumi Hosono ◽  
Nicolas Oliveira Decarli ◽  
Paola Zimmermann Crocomo ◽  
Tsuyoshi Goya ◽  
Leonardo Evaristo de Sousa ◽  
...  
Keyword(s):  
Excited State ◽  
Room Temperature ◽  
Delayed Fluorescence ◽  
Quantum Yields ◽  
Room Temperature Phosphorescence ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Thermally Activated ◽  
Donor Acceptor ◽  
Emission Behavior

Exploring design principle for switching thermally activated dealyed fluorescecne (TADF) and room temperature phosphorescence (RTP) is a fundamentally imporant research in developing triplet-mediated photofunctional organic materials. Herein systematic studies on the regioisomeric and substituents effects in a twisted donor–acceptor–donor (D–A–D) scaffold (A = dibenzo[a,j]phenazine; D = dihydrophenazasiline) on the fate of the excited state have been performed. The study revealed that the regiosiomerism clearly affects the emission behavior of the D–A–D compounds. Distinct difference in TADF, dual TADF & RTP, and dual RTP were observed, depending on the host used. Furthermore, OLED organic light-emitting diodes (OLEDs) fabricated with the developed emitters achieved high external quantum yields for RTP-based OLEDS up to 7.4%.

scholarly journals Synthesis and optoelectronic properties of benzoquinone-based donor–acceptor compounds

2019 ◽  
Vol 15 ◽  
pp. 2914-2921
Author(s):  
Daniel R Sutherland ◽  
Nidhi Sharma ◽  
Georgina M Rosair ◽  
Ifor D W Samuel ◽  
Ai-Lan Lee ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Delayed Fluorescence ◽  
Optoelectronic Properties ◽  
Donor Group ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Palladium Catalyzed ◽  
Donor Acceptor

Herein, we report a mild and efficient palladium-catalyzed C–H functionalization method to synthesize a series of benzoquinone (BQ)-based charge-transfer (CT) derivatives in good yields. The optoelectronic properties of these compounds were explored both theoretically and experimentally and correlations to their structures were identified as a function of the nature and position of the donor group (meta and para) attached to the benzoquinone acceptor. Compound 3, where benzoquinone is para-conjugated to the diphenylamine donor group, exhibited thermally activated delayed fluorescence (TADF) with a biexponential lifetime characterized by a prompt ns component and a delayed component of 353 μs.

Potential thermally activated delayed fluorescence properties of a series of 2,3-dicyanopyrazine based compounds

2018 ◽  
Vol 3 (7) ◽  
Author(s):  
Ayşegül Gümüş ◽  
Selçuk Gümüş
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Delayed Fluorescence ◽  
Basis Sets ◽  
Functional Theory ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Structural And Electronic Properties ◽  
Donor Acceptor ◽  
Almost All

Abstract 2,3-Dicyanopyrazine based acceptor was combined with a series of well studied donors to obtain donor-acceptor type potential thermally activated delayed fluorescence emitters. Their structural and electronic properties were computed theoretically at the level of density functional theory and time dependent density functional theory with the application of two different hybrid functionals and various basis sets. Almost all of the designed structures were computed to have the potential of being TADF compounds since they possess very narrow singlet-triplet gaps. Indeed, acridine-pyrazine (9) derivative was calculated to be the best candidate for the purpose among them.

The Role of Electron–Hole Separation in Thermally Activated Delayed Fluorescence in Donor–Acceptor Blends

2015 ◽  
Vol 119 (45) ◽  
pp. 25591-25597 ◽  
Author(s):  
Eric Hontz ◽  
Wendi Chang ◽  
Daniel N. Congreve ◽  
Vladimir Bulović ◽  
Marc A. Baldo ◽  
...  
Keyword(s):  
Delayed Fluorescence ◽  
Electron Hole ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Donor Acceptor

scholarly journals Intermolecular interactions in molecular crystals and their effect on thermally activated delayed fluorescence of helicene-based emitters

2018 ◽  
Vol 6 (39) ◽  
pp. 10557-10568 ◽  
Author(s):  
Anastasia Klimash ◽  
Piotr Pander ◽  
Wim T. Klooster ◽  
Simon J. Coles ◽  
Przemyslaw Data ◽  
...  
Keyword(s):  
Intermolecular Interactions ◽  
Molecular Crystals ◽  
Delayed Fluorescence ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Donor Acceptor

In crystals of donor–acceptor helicene molecules, thermally activated delayed fluorescence (TADF) is strongly enhanced by the presence of occluded hexane molecules.

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