Overcoming Low Orbital Overlap and Triplet Instability Problems in TDDFT

2012 ◽  
Vol 116 (39) ◽  
pp. 9783-9789 ◽  
Author(s):  
Michael J. G. Peach ◽  
David J. Tozer
Keyword(s):  
Triplet Instability

Singlet and triplet instability theorems

2015 ◽  
Vol 143 (11) ◽  
pp. 114112 ◽  
Author(s):  
Tomonori Yamada ◽  
So Hirata
Keyword(s):  
Triplet Instability

scholarly journals The Hartree–Fock triplet instability: influence of conformation and substitution

2006 ◽  
Vol 760 (1-3) ◽  
pp. 75-85 ◽  
Author(s):  
Christine Geron ◽  
George Dive ◽  
Dominique Dehareng
Keyword(s):  
Hartree Fock ◽  
Triplet Instability

Polyacene stability and the mechanism producing a new solution at the Hartree-Fock triplet instability threshold

1985 ◽  
Vol 26 (2) ◽  
pp. 164-170 ◽  
Author(s):  
M. M. Mestechkin ◽  
G. E. Vaiman ◽  
A. L. Vul'fov
Keyword(s):  
Instability Threshold ◽  
Hartree Fock ◽  
Triplet Instability

scholarly journals TD-DFT and Experimental Methods for Unraveling the Energy Distribution of Charge-Transfer Triplet/Singlet States of a TADF Molecule in a Frozen Matrix

2020 ◽  
Author(s):  
Seung-Je Woo ◽  
Jang-Joo Kim
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Energy Distribution ◽  
Dihedral Angle ◽  
Energy Band ◽  
Td Dft ◽  
Donor Acceptor ◽  
Transfer State ◽  
Conformational Distribution ◽  
Triplet Instability

Reverse intersystem crossing (RISC) rate of a thermally activated delayed fluorescence (TADF) molecule is sensitive to the energy alignment of singlet charge-transfer state (<sup>1</sup>CT), triplet charge-transfer state (<sup>3</sup>CT), and locally excited triplet state (<sup>3</sup>LE). However, the energy distribution of the charge-transfer states originating from the conformational distribution of TADF molecules in a solid matrix inevitably generated during the preparation of a solid sample due to the rotatable donor-acceptor linkage is rarely considered. Moreover, the investigation of the energy distribution of the <sup>3</sup>CT state is both theoretically and experimentally difficult due to the triplet instabilities of time-dependent density functional (TD-DFT) calculations and difficulties in phosphorescence measurements, respectively. As a result, the relation between conformational distribution, configurations of excited state transition orbitals, and excited state energies/dynamics have not been clearly explained. In this work, we determined the energy distribution of CT states of the TADF emitter TPSA in frozen toluene at 77 K by the measurement of time-resolved spectra in the full time range (1 ns ~ 30 s) of emission including prompt fluorescence, TADF, <sup>3</sup>CT phosphorescence, and <sup>3</sup>LE phosphorescence. We obtained the energy band of CT states where <sup>1</sup>CT and <sup>3</sup>CT states are distributed in the range of 2.85-3.00 eV and 2.64-2.96 eV, respectively. We tested various global hybrid and long-range corrected functionals for the TD-DFT calculation of <sup>3</sup>CT energy of TPSA and found that only the M11 functional shows consistent results without triplet instability. We performed TD-DFT with the M11* functional optimized for robust dihedral angle scan of <sup>3</sup>CT states without triplet instability and reproduced the energy band structure obtained from the experiment. Through TD-DFT and experimental investigations, it is estimated that the dihedral angle of donor-acceptor (θ<sub>D-A</sub>) and acceptor-linker (θ<sub>A</sub>) of TPSA in frozen toluene lie within the range of 70°≤θ<sub>D-A</sub>≤90° and 0°≤θ<sub>A</sub>≤30° respectively. Our results show that the dihedral angle distribution must be considered for further investigation of the photophysics of TADF molecules and the development of stable and efficient TADF emitters.

Triplet instability in doublet systems

2004 ◽  
Vol 121 (16) ◽  
pp. 7624 ◽  
Author(s):  
Péter G. Szalay ◽  
Juana Vázquez ◽  
Chris Simmons ◽  
John F. Stanton
Keyword(s):  
Triplet Instability

On the triplet instability in TDDFT

2013 ◽  
Vol 111 (9-11) ◽  
pp. 1271-1274 ◽  
Author(s):  
Michael J.G. Peach ◽  
Neil Warner ◽  
David J. Tozer
Keyword(s):  
Triplet Instability

Triplet instability in semiempiricalRPA calculations of conjugated systems containing heteroatoms

1979 ◽  
Vol 16 (5) ◽  
pp. 1151-1155
Author(s):  
A. B. Sannigrahi ◽  
B. Guha Niyogi
Keyword(s):  
Conjugated Systems ◽  
Triplet Instability

scholarly journals Ansatz for the Jahn–Teller triplet instability

2020 ◽  
Vol 153 (17) ◽  
pp. 174110
Author(s):  
Arnout Ceulemans ◽  
P. Bernát Szabó
Keyword(s):  
Jahn Teller ◽  
Triplet Instability

On the triplet instability in semiempiricalRPA calculations of conjugated hydrocarbons

1978 ◽  
Vol 14 (3) ◽  
pp. 337-340 ◽  
Author(s):  
B. Guha Niyogi ◽  
A. B. Sannigrahi
Keyword(s):  
Conjugated Hydrocarbons ◽  
Triplet Instability

scholarly journals TD-DFT and Experimental Methods for Unraveling the Energy Distribution of Charge-Transfer Triplet/Singlet States of a TADF Molecule in a Frozen Matrix

2020 ◽  
Author(s):  
Seung-Je Woo ◽  
Jang-Joo Kim
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Energy Distribution ◽  
Dihedral Angle ◽  
Energy Band ◽  
Td Dft ◽  
Donor Acceptor ◽  
Transfer State ◽  
Conformational Distribution ◽  
Triplet Instability

Reverse intersystem crossing (RISC) rate of a thermally activated delayed fluorescence (TADF) molecule is sensitive to the energy alignment of singlet charge-transfer state (<sup>1</sup>CT), triplet charge-transfer state (<sup>3</sup>CT), and locally excited triplet state (<sup>3</sup>LE). However, the energy distribution of the charge-transfer states originating from the conformational distribution of TADF molecules in a solid matrix inevitably generated during the preparation of a solid sample due to the rotatable donor-acceptor linkage is rarely considered. Moreover, the investigation of the energy distribution of the <sup>3</sup>CT state is both theoretically and experimentally difficult due to the triplet instabilities of time-dependent density functional (TD-DFT) calculations and difficulties in phosphorescence measurements, respectively. As a result, the relation between conformational distribution, configurations of excited state transition orbitals, and excited state energies/dynamics have not been clearly explained. In this work, we determined the energy distribution of CT states of the TADF emitter TPSA in frozen toluene at 77 K by the measurement of time-resolved spectra in the full time range (1 ns ~ 30 s) of emission including prompt fluorescence, TADF, <sup>3</sup>CT phosphorescence, and <sup>3</sup>LE phosphorescence. We obtained the energy band of CT states where <sup>1</sup>CT and <sup>3</sup>CT states are distributed in the range of 2.85-3.00 eV and 2.64-2.96 eV, respectively. We tested various global hybrid and long-range corrected functionals for the TD-DFT calculation of <sup>3</sup>CT energy of TPSA and found that only the M11 functional shows consistent results without triplet instability. We performed TD-DFT with the M11* functional optimized for robust dihedral angle scan of <sup>3</sup>CT states without triplet instability and reproduced the energy band structure obtained from the experiment. Through TD-DFT and experimental investigations, it is estimated that the dihedral angle of donor-acceptor (θ<sub>D-A</sub>) and acceptor-linker (θ<sub>A</sub>) of TPSA in frozen toluene lie within the range of 70°≤θ<sub>D-A</sub>≤90° and 0°≤θ<sub>A</sub>≤30° respectively. Our results show that the dihedral angle distribution must be considered for further investigation of the photophysics of TADF molecules and the development of stable and efficient TADF emitters.

Sign in / Sign up

Export Citation Format

Share Document