scholarly journals Getting the Right Twist: Influence of Donor–Acceptor Dihedral Angle on Exciton Kinetics and Singlet–Triplet Gap in Deep Blue Thermally Activated Delayed Fluorescence Emitter

2019 ◽  
Vol 123 (45) ◽  
pp. 27778-27784 ◽  
Author(s):  
Sebastian Weissenseel ◽  
Nikita A. Drigo ◽  
Liudmila G. Kudriashova ◽  
Markus Schmid ◽  
Thomas Morgenstern ◽  
...  
Keyword(s):  
Dihedral Angle ◽  
Delayed Fluorescence ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Deep Blue ◽  
Donor Acceptor ◽  
The Right

scholarly journals (Deep) blue through-space conjugated TADF emitters based on [2.2]paracyclophanes

2018 ◽  
Vol 54 (67) ◽  
pp. 9278-9281 ◽  
Author(s):  
Eduard Spuling ◽  
Nidhi Sharma ◽  
Ifor D. W. Samuel ◽  
Eli Zysman-Colman ◽  
Stefan Bräse
Keyword(s):  
Delayed Fluorescence ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Deep Blue ◽  
Donor Acceptor

The first examples of through-space conjugated thermally activated delayed fluorescence (TADF) emitters based on a [2.2]paracyclophane (PCP) skeleton with stacked (coplanar) donor–acceptor groups have been synthesized.

scholarly journals Pyrimidine-based twisted donor–acceptor delayed fluorescence molecules: a new universal platform for highly efficient blue electroluminescence

2017 ◽  
Vol 8 (2) ◽  
pp. 953-960 ◽  
Author(s):  
In Seob Park ◽  
Hideaki Komiyama ◽  
Takuma Yasuda
Keyword(s):  
High Efficiency ◽  
Delayed Fluorescence ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Highly Efficient ◽  
Deep Blue ◽  
Donor Acceptor

High-efficiency deep blue thermally activated delayed fluorescence (TADF) emitters consisting of acridan–pyrimidine donor–acceptor motifs are developed.

scholarly journals Exploring the possibility of using fluorine-involved non-conjugated electron-withdrawing groups for thermally activated delayed fluorescence emitters by TD-DFT calculation

2021 ◽  
Vol 17 ◽  
pp. 210-223
Author(s):  
Dongyang Chen ◽  
Eli Zysman-Colman
Keyword(s):  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Delayed Fluorescence ◽  
Type I ◽  
Type Ii ◽  
Triplet Energy ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Deep Blue ◽  
Donor Acceptor

The trifluoromethyl group has been previously explored as a non-conjugated electron-withdrawing group in donor–acceptor thermally activated delayed fluorescence (TADF) emitters. In the present study, we investigate computationally the potential of other fluorine-containing acceptors, trifluoromethoxy (OCF3), trifluoromethylthio (SCF3), and pentafluorosulfanyl (SF5), within two families of donor–acceptor TADF emitters. Time-dependent density functional theory calculations indicate that when only two ortho-disposed carbazole donors are used (Type I molecules), the lowest-lying triplet state possesses locally excited (LE) character while the lowest-lying singlet state possesses charge-transfer character. When five carbazole donors are present in the emitter design (Type II molecules), now both S1 and T1 states possess CT character. For molecules 2CzOCF 3 and 5CzOCF 3 , the singlet energies are predicted to be 3.92 eV and 3.45 eV; however, the singlet-triplet energy gaps, ΔE STs, are predicted to be large at 0.46 eV and 0.37 eV, respectively. The compounds 2CzCF 3 , 2CzSCF 3 , and 2CzSF 5 , from Type I molecules, show significant promise as deep blue TADF emitters, possessing high calculated singlet energies in the gas phase (3.62 eV, 3.66 eV, and 3.51 eV, respectively) and small, ΔE STs, of 0.17 eV, 0.22 eV, and 0.07 eV, respectively. For compounds 5CzSCF 3 and 5CzSF 5 , from Type II molecules, the singlet energies are stabilized to 3.24 eV and 3.00 eV, respectively, while ΔE STs are 0.27 eV and 0.12 eV, respectively, thus both show promise as blue or sky-blue TADF emitters. All these six molecules possess a dense number of intermediate excited states between S1 and T1, thus likely leading to a very efficient reverse intersystem crossing in these compounds.

Donor–acceptor materials exhibiting deep blue emission and thermally activated delayed fluorescence with tris(triazolo)triazine

2021 ◽  
Author(s):  
Ryoga Hojo ◽  
Don M. Mayder ◽  
Zachary M. Hudson
Keyword(s):  
Blue Emission ◽  
Delayed Fluorescence ◽  
Fluorescence Properties ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Two Photon ◽  
Deep Blue ◽  
Donor Acceptor ◽  
Two Photon Fluorescence ◽  
Photon Fluorescence

Five emitters with the tris(triazolo)triazine acceptor core are reported, with emission from deep blue to green. These emitters show promising thermally activated delayed fluorescence and/or two-photon fluorescence properties.

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%.

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