scholarly journals Investigation of Thermally Activated Delayed Fluorescence from a Donor–Acceptor Compound with Time-Resolved Fluorescence and Density Functional Theory Applying an Optimally Tuned Range-Separated Hybrid Functional

2020 ◽  
Vol 124 (8) ◽  
pp. 1535-1553 ◽  
Author(s):  
Reinhard Scholz ◽  
Paul Kleine ◽  
Ramunas Lygaitis ◽  
Ludwig Popp ◽  
Simone Lenk ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Delayed Fluorescence ◽  
Time Resolved Fluorescence ◽  
Hybrid Functional ◽  
Functional Theory ◽  
Time Resolved ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Donor Acceptor

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.

Computational study on thermally activated delayed fluorescence of donor–linker–acceptor network molecules

RSC Advances ◽  
2016 ◽  
Vol 6 (43) ◽  
pp. 37203-37211 ◽  
Author(s):  
Talapunur Vikramaditya ◽  
Mukka Saisudhakar ◽  
Kanakamma Sumithra
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Organic Molecules ◽  
Computational Study ◽  
Delayed Fluorescence ◽  
Structure Property ◽  
Functional Theory ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Structure Property Relationships

Using density functional theory we have investigated the structure–property relationships of organic molecules with a donor–linker–acceptor (DLA) framework, which can be used as precursors of OLED materials.

Theoretical Study on Benzazole Derivatives for Use in Blue Thermally Activated Delayed Fluorescence Emitters

2015 ◽  
Vol 15 (10) ◽  
pp. 7819-7822 ◽  
Author(s):  
Dong Yuel Kwon ◽  
Geon Hyeong Lee ◽  
Young Sik Kim
Keyword(s):  
Density Functional Theory ◽  
Molecular Orbital ◽  
Density Functional ◽  
Light Emitting Diode ◽  
Energy Difference ◽  
Delayed Fluorescence ◽  
Functional Theory ◽  
Thermally Activated Delayed Fluorescence ◽  
Organic Light Emitting Diode ◽  
Thermally Activated

Four novel thermally activated delayed fluorescence (TADF) materials with 9,10-dihydro-9,9- dimethylacridine (DMAC) and phenylindolo(2,3-a)carbazole (PIC) as electron donors and benzazole derivatives (BO, and BT) as electron acceptors (DMAC-BO, DMAC-BT, PIC-BO, and PIC-BT) were designed and theoretically investigated for use as a blue organic light emitting diode (OLED) emitter. Using density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations, we calculated the electron distribution of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), and the energy of the lowest singlet (S1) and the lowest triplet (T1) excited states. All the dyes had a small spatial overlap between the HOMO and LUMO because of the relatively large dihedral angle between the phenyl ring and the acceptor moiety. In terms of the energy difference (ΔEST) between the S1 state and the T1 state, DMAC-BO and DMAC-BT showed the small ΔEST (0.18 eV and 0.21 eV, respectively). However, PIC-BO and PIC-BT showed the large ΔEST (0.62 eV and 0.61 eV, respectively). Among the TADF materials, we showed that DMAC-BO would have the best TADF properties in terms of small ΔEST and blue OLED emitters

scholarly journals Solution-Processed OLEDs Based on Thermally Activated Delayed Fluorescence Copper(I) Complexes with Intraligand Charge-Transfer Excited State

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1125
Author(s):  
Teng Teng ◽  
Jinfan Xiong ◽  
Gang Cheng ◽  
Changjiang Zhou ◽  
Xialei Lv ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Density Functional ◽  
Delayed Fluorescence ◽  
Quantum Yields ◽  
Functional Theory ◽  
Solution Processed ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Thermally Activated ◽  
Wide Range

A new series of tetrahedral heteroleptic copper(I) complexes exhibiting efficient thermally-activated delayed fluorescence (TADF) in green to orange electromagnetic spectral regions has been developed by using D-A type N^N ligand and P^P ligands. Their structures, electrochemical, photophysical, and electroluminescence properties have been characterized. The complexes exhibit high photoluminescence quantum yields (PLQYs) of up to 0.71 at room temperature in doped film and the lifetimes are in a wide range of 4.3–24.1 μs. Density functional theory (DFT) calculations on the complexes reveal the lowest-lying intraligand charge-transfer excited states that are localized on the N^N ligands. Solution-processed organic light emitting diodes (OLEDs) based on one of the new emitters show a maximum external quantum efficiency (EQE) of 7.96%.

Theoretical Study of Phenoxaphosphine-Based Blue Organic Light-Emitting Diode Exhibiting Thermally Activated Delayed Fluorescence

2020 ◽  
Vol 20 (11) ◽  
pp. 7187-7190
Author(s):  
JaMin Lee ◽  
Sae Won Lee ◽  
Young Sik Kim
Keyword(s):  
Density Functional ◽  
Light Emitting Diode ◽  
Energy Difference ◽  
Delayed Fluorescence ◽  
Functional Theory ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Thermally Activated ◽  
Organic Light

We designed novel thermally activated delayed fluorescence (TADF) materials by combining the electron donors spiro[acridine-9,9′-fluorene] (D1) and 9,9-diphenyl acridan (PAC) with the electron acceptor phenoxaphosphine (OPO) unit (2D1-OPO and 2PAC-OPO) and used those property to compare it with that of the reference material using dimethylacridan (Ac) as an electron donor (Ac-OPO) for blue organic light-emitting diodes (OLEDs). To calculate electron distribution of highest occupied molecular orbitals (HOMO), lowest occupied molecular orbital (LUMO), lowest singlet (S1) energy and lowest triplet (T1) excitation states, density functional theory (DFT) and time-dependent DFT calculation have been used. The calculated energy difference (ΔEST) between the S1 and T1 states of 2D1-OPO (0.125 eV) and 2PAC-OPO (0.153 eV) were as small as that of Ac-OPO (0.127 eV). The results showed that 2D1-OPO is a good candidate for blue OLED emitter because it has an emission wavelength of 441.0 nm as well as a sufficiently small ΔEST value and large oscillator intensity value.

scholarly journals Characterization of Excited States in a Multiple-Resonance-Type Thermally Activated Delayed Fluorescence Molecule Using Time-resolved Infrared Spectroscopy

2021 ◽  
Author(s):  
Yuushi Shimoda ◽  
Masaki Saigo ◽  
Tomohiro Ryu ◽  
Takumi Ehara ◽  
Kiyoshi Miyata ◽  
...  
Keyword(s):  
Excited State ◽  
Density Functional ◽  
Photophysical Properties ◽  
Delayed Fluorescence ◽  
Potential Surfaces ◽  
Time Resolved ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Multiple Resonance ◽  
Time Resolved Infrared Spectroscopy

We have investigated the correlation between the photophysical properties and the excited-state detailed characteristics in a multiple-resonance-type thermally activated delayed fluorescence (TADF) molecule, DABNA-1, using time-resolved infrared vibrational spectroscopy. In comparison of the distinctive vibrational spectra in the fingerprint region, 1000 - 1700 cm<sup>-1</sup>, to the simulated spectra by density functional theory calculations, we found the best calculation condition. On the basis of the calculations, we determined the excited-state geometries and molecular orbitals of the lowest excited singlet (S<sub>1</sub>) and triplet (T<sub>1</sub>) states as well as the ground state (S<sub>0</sub>). We revealed that the similarity of the potential surfaces between T<sub>1</sub> and S<sub>0</sub> suppresses the nonradiative decay and causes the high fluorescence quantum yield via TADF process.

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.

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