2019 Fiscal Year Annual Research Report
Enhanced TADF Activity with Exciton Interaction toward Circularly Polarized OLED
| Project/Area Number |
19F19342
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| Research Institution | Nara Institute of Science and Technology |
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Principal Investigator |
河合 壯 奈良先端科学技術大学院大学, 先端科学技術研究科, 教授 (40221197)
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| Co-Investigator(Kenkyū-buntansha) |
LOUIS MARINE 奈良先端科学技術大学院大学, .先端科学技術研究科, 外国人特別研究員
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| Project Period (FY) |
2019-11-08 – 2022-03-31
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| Keywords | TADF / CPL / OLED / fluorescence |
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| Outline of Annual Research Achievements |
The goal of this project is to design new pure-organic TADF and CPL emitters for the development of new CP-OLEDｓ. Since CP-OLED is practically expected as a future candidate for highly efficient OLED with efficient light extraction efficiency. This is the cutting edge research target exploring efficient CP-OLED material and devices which are based on the thermally activated delayed fluorescence, TADF. This research is divided in two parts: synthetic organic chemistry and photo-physical analyses. At first, several molecular designs were discussed and various promising molecules, able to potentially form supramolecular structures, based on donor-acceptor patterns and including a substantial range of chiral moieties, have been selected. Multiple syntheses were conducted simultaneously. Following experimental observations and syntheses outcomes, some of the initial targets have been modified, redesigned and some synthetic pathways are presently being optimized. In the meantime, DFT calculations are performed for each targets and optimizations of the calculation methods are ongoing to get a realistic modelling of the singlet/triplet (delta-EST) energy gap and of the frontier (HOMO-LUMO) orbitals.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
In the first part of this project, the synthesis of new targets was supposed to be the main focus of the research work. As expected, after thoughtful considerations of the design of the different targets, during those first 5 months I have focused on the syntheses of those emitters. The syntheses are still ongoing after optimization of the targets structures and after experimental observations. Soon photo-physical analyses should get started as well as optical spectroscopy and CPL measurements.
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| Strategy for Future Research Activity |
The synthesis of the design molecules will be pursued, completed and optimized. The photo-physical properties of the different targets will be investigated such as luminescence (absorption, emission, excitation spectra, time-resolved fluorescence spectroscopy, characterization of the TADF emission), IR and their CD/CPL nature. Each results will be thoroughly analyzed. Depending on the experimental results with comparison with the calculations performed, an optimization of the synthesized emitters: modification of the chiral moieties, modifying the donor and/or acceptor structure, introducing new chromophores to the structure, will be realized to obtain an increase in the desired performances. A discussion will be introduced with Prof. Reineke as Dresden, Germany aiming at promoting a future collaboration for the testing of the most promising emitters in OLEDs devices.
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