2016 Fiscal Year Final Research Report
A theoretical method for visualizing the origin of radiative and non-radiative decays and its application to molecular design for deep-blue electroluminescent materials
| Project/Area Number |
15K17900
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Organic and hybrid materials
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| Research Institution | Kyoto University |
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Principal Investigator |
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| Project Period (FY) |
2015-04-01 – 2017-03-31
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| Keywords | 有機EL / 輻射失活 / 無輻射失活 / 重なり密度 / 遷移双極子モーメント / 振電相互作用 / 熱活性化型遅延蛍光 |
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| Outline of Final Research Achievements |
Rates of radiative decay (fluorescence, kr) and non-radiative decay (thermal deactivation, knr) of a molecule are expressed in terms of overlap density between wave functions of the ground and excited states of a molecule. For exiting fluorescent compounds, the relationship between overlap density and luminescence efficiency was investigated theoretically. From the theoretical analyses, kr was found to be largely increased by extending the distribution range of overlap density to regions distant from the coordinate origin. Using this design principle, an acceptor-donor-acceptor-type blue emitter, CzX, was developed. From transient photoluminescence measurements of a CzX-doped host matrix, CzX was found to show delayed fluorescence (DF). An organic light-emitting diode (OLED) containing CzX as an emitting dopant was fabricated. The OLED showed blue emission and the maximum external quantum efficiency (EQE) of 19.9%. The high EQE probably results from efficient DF from CzX.
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| Free Research Field |
材料化学
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