2021 Fiscal Year Final Research Report
Elucidation of operation mechanisms of next-generation high-luminance organic light-emitting devices
Project/Area Number |
19K21955
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Research Category |
Grant-in-Aid for Challenging Research (Exploratory)
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Allocation Type | Multi-year Fund |
Review Section |
Medium-sized Section 21:Electrical and electronic engineering and related fields
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Research Institution | University of Tsukuba |
Principal Investigator |
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Project Period (FY) |
2019-06-28 – 2022-03-31
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Keywords | 有機発光デバイス / 素子動作機構 / 電子スピン共鳴 / 発光電気化学セル / 有機イオントロ二クス |
Outline of Final Research Achievements |
In this study, we have performed an electron spin resonance (ESR) study of light-emitting electrochemical cells (LECs) using a blue emission Host polymer, a triplet-triplet annihilation (TTA) polymer, and a mixed polymer blend of these polymers in the device driving states (operando states). The device structure is ITO transparent anode/emission layer/Ag cathode. The charge-derived spins doped in the emitting layer by electrochemical doping during device operation were directly observed by operando ESR, and the types of doped charges were identified from ESR analysis and their absolute numbers were evaluated to clarify the charge-doping progression process during LEC operation. We also studied the formation states and operation mechanism of triplet excitons when the ratio of Host polymer to TTA polymer was changed.
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Free Research Field |
有機無機半導体
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Academic Significance and Societal Importance of the Research Achievements |
研究成果の学術的意義は、これまでの有機発光デバイスの研究では殆ど用いられていなかった電子スピン共鳴(ESR)分光を活用し、素子内部を微視的な視点から非破壊で素子動作時(オペランド状態)に観測し、素子動作機構を分子レベルで解明できるようになる点が挙げられる。従来手法では電荷ドーピング状態や形成過程等について直接的な観測が出来ず、素子中の電荷状態や動作機構等を微視的な視点から明らかに出来ない問題点があった。 研究成果の社会的意義は、オペランドESR研究から得られた素子動作機構に基づいて、分子・素子構造の最適化を行え、素子の高特性化が容易となる点が挙げられる。
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