Direct Observation of Photoexcited Electron Dynamics in Organic Solids Exhibiting Thermally Activated Delayed Fluorescence via Time‐Resolved Photoelectron Emission Microscopy

2021 ◽  
pp. 2100619
Author(s):  
Yusuke Fukami ◽  
Masato Iwasawa ◽  
Masahiro Sasaki ◽  
Takuya Hosokai ◽  
Hajime Nakanotani ◽  
...  
Keyword(s):  
Direct Observation ◽  
Delayed Fluorescence ◽  
Electron Dynamics ◽  
Photoelectron Emission ◽  
Photoexcited Electron ◽  
Organic Solids ◽  
Time Resolved ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Emission Microscopy

Solvent Dependence of Structural Dynamics and Spin-flip Processes in 3,4,5-tri(9H-carbazole-9-yl)benzonitrile (ortho-3CzBN)

2020 ◽  
Author(s):  
Masaki Saigo ◽  
Kiyoshi Miyata ◽  
Hajime Nakanotani ◽  
Chihaya Adachi ◽  
Ken Onda
Keyword(s):  
Dft Calculations ◽  
Excited States ◽  
Structural Changes ◽  
Photophysical Properties ◽  
Delayed Fluorescence ◽  
Time Resolved ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Solvent Dependence ◽  
Acetonitrile Solutions

We have investigated the solvent-dependence of structural changes along with intersystem crossing of a thermally activated delayed fluorescence (TADF) molecule, 3,4,5-tri(9H-carbazole-9-yl)benzonitrile (o-3CzBN), in toluene, tetrahydrofuran, and acetonitrile solutions using time-resolved infrared (TR-IR) spectroscopy and DFT calculations. We found that the geometries of the S1 and T1 states are very similar in all solvents though the photophysical properties mostly depend on the solvent. In addition, the time-dependent DFT calculations based on these geometries suggested that the thermally activated delayed fluorescence process of o-3CzBN is governed more by the higher-lying excited states than by the structural changes in the excited states.<br>

scholarly journals Thermally activated delayed fluorescence vs. room temperature phosphorescence by conformation control of organic single molecules

2019 ◽  
Vol 7 (22) ◽  
pp. 6616-6621 ◽  
Author(s):  
Przemyslaw Data ◽  
Masato Okazaki ◽  
Satoshi Minakata ◽  
Youhei Takeda
Keyword(s):  
Room Temperature ◽  
Single Molecules ◽  
Delayed Fluorescence ◽  
Room Temperature Phosphorescence ◽  
Time Resolved ◽  
Thermally Activated Delayed Fluorescence ◽  
Molecular Conformations ◽  
Thermally Activated ◽  
Luminescent Compound

The time-resolved photophysical analysis of a multi-color-changing mechanochromic luminescent compound has been disclosed, which reveals distinct different emission paths to boost TADF and RTP of the emitter depending on its molecular conformations.

Solvent Dependence of Structural Dynamics and Spin-flip Processes in 3,4,5-tri(9H-carbazole-9-yl)benzonitrile (ortho-3CzBN)

2020 ◽  
Author(s):  
Masaki Saigo ◽  
Kiyoshi Miyata ◽  
Hajime Nakanotani ◽  
Chihaya Adachi ◽  
Ken Onda
Keyword(s):  
Dft Calculations ◽  
Excited States ◽  
Structural Changes ◽  
Photophysical Properties ◽  
Delayed Fluorescence ◽  
Time Resolved ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Solvent Dependence ◽  
Acetonitrile Solutions

We have investigated the solvent-dependence of structural changes along with intersystem crossing of a thermally activated delayed fluorescence (TADF) molecule, 3,4,5-tri(9H-carbazole-9-yl)benzonitrile (o-3CzBN), in toluene, tetrahydrofuran, and acetonitrile solutions using time-resolved infrared (TR-IR) spectroscopy and DFT calculations. We found that the geometries of the S1 and T1 states are very similar in all solvents though the photophysical properties mostly depend on the solvent. In addition, the time-dependent DFT calculations based on these geometries suggested that the thermally activated delayed fluorescence process of o-3CzBN is governed more by the higher-lying excited states than by the structural changes in the excited states.<br>

Direct Observation of Spin States Involved in Organic Electroluminescence Based on Thermally Activated Delayed Fluorescence

2016 ◽  
Vol 5 (3) ◽  
pp. 1600926 ◽  
Author(s):  
Stefan Väth ◽  
Kristofer Tvingstedt ◽  
Michael Auth ◽  
Andreas Sperlich ◽  
Asta Dabuliene ◽  
...  
Keyword(s):  
Direct Observation ◽  
Delayed Fluorescence ◽  
Spin States ◽  
Thermally Activated Delayed Fluorescence ◽  
Organic Electroluminescence ◽  
Thermally Activated

scholarly journals Direct observation of intersystem crossing in a thermally activated delayed fluorescence copper complex in the solid state

2016 ◽  
Vol 2 (1) ◽  
pp. e1500889 ◽  
Author(s):  
Larissa Bergmann ◽  
Gordon J. Hedley ◽  
Thomas Baumann ◽  
Stefan Bräse ◽  
Ifor D. W. Samuel
Keyword(s):  
Solid State ◽  
Delayed Fluorescence ◽  
Average Lifetime ◽  
Intersystem Crossing ◽  
Time Resolved ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Thermally Activated ◽  
Singlet States ◽  
Time Resolved Photoluminescence

Intersystem crossing in thermally activated delayed fluorescence (TADF) materials is an important process that controls the rate at which singlet states convert to triplets; however, measuring this directly in TADF materials is difficult. TADF is a significant emerging technology that enables the harvesting of triplets as well as singlet excited states for emission in organic light emitting diodes. We have observed the picosecond time-resolved photoluminescence of a highly luminescent, neutral copper(I) complex in the solid state that shows TADF. The time constant of intersystem crossing is measured to be 27 picoseconds. Subsequent overall reverse intersystem crossing is slow, leading to population equilibration and TADF with an average lifetime of 11.5 microseconds. These first measurements of intersystem crossing in the solid state in this class of mononuclear copper(I) complexes give a better understanding of the excited-state processes and mechanisms that ensure efficient TADF.

Time-Resolved Thermally Activated Delayed Fluorescence in C70and 1,2-C70H2

2000 ◽  
Vol 104 (48) ◽  
pp. 11265-11269 ◽  
Author(s):  
Sergei M. Bachilo ◽  
Angelo F. Benedetto ◽  
R. Bruce Weisman ◽  
Jamie R. Nossal ◽  
W. Edward Billups
Keyword(s):  
Delayed Fluorescence ◽  
Time Resolved ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated
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