2015 Fiscal Year Annual Research Report
| Project/Area Number |
15J02752
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| Research Institution | Tohoku University |
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Principal Investigator |
穆 帥 東北大学, 理学研究科, 特別研究員(DC1)
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| Project Period (FY) |
2015-04-24 – 2018-03-31
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| Keywords | red luminescence / highly emissive crystal / AIE / optical waveguide / ambipolar |
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| Outline of Annual Research Achievements |
Development of highly emissive materials for optoelectronic devices is a hot topic of scientific research in the past decades. For RGB (red, green, blue) colors, photoluminescence (PL) quantum yield of red color is normally much lower than that of blue and green colors. Red luminescence comes from the luminophor with a narrow HOMO-LUMO energy gap, which is easy to result in non-radiative recombination of excitons. Therefore, high quality red-emitting materials with confined emitting properties for optoelectronic devices are very limited.
In current work, we developed a novel molecular crystal of CNP2V2TT. Crystallographic data indicates the existence of C-H...N hydrogen bonding change the common herringbone stacking motif to an uniaxially oriented molecular packing with slipped face to face intermolecular π-π stacking. CNP2V2TT single crystal exhibits high quality red luminescence and aggregation induced emission (AIE) property with a very high photoluminescence quantum yield up to 37%. CNP2V2TT single crystal also exhibits optical waveguide edge emission. On the other hand, balanced ambipolar charge mobilities with μe up to 0.13 cm2 V-1 s-1 and μh up to 0.085 cm2 V-1 s-1 were achieved from the single crystal FET devices using Au and Ca as hole and electron injection electrodes, respectively. Our research demonstrates CNP2V2TT sing crystal is a promising highly emissive red-emitting material with confined emitting properties for optoelectronic and photonic applications.
Relevant work was published on the journal “Organic Electronics 34 (2016) 23-27”.
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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
Development of highly emissive materials in the solid state is a crucial prerequiste for optoelectronic and photonic devices. Organic single crystal has attracted much attention in resent years due to its distinct merits. Unlike amorphous materials, organic single crystals exhibit various regular intermolecular aggregation manners such as H-aggregate or J-aggregate, which gives a unique horizon to modulate optical properties of organic single crystal by careful design of molecular features.On the other hand, organic single crystal possesses few grain boundaries and defects, which contribute to achieve high charge mobility and current density. Therefor, the initial purpose of our project is to design novel organic molecular crystals with high luminescence and charge transport properties towards the development of optoelectronic and photonic applications.
In current status, we successfully developed a high quality red luminescent molecular crystal CNP2V2TT, which exibits aggregation induced emission, optical waveguide edge emission and balanced ambipolar carrier transpot. Our research demonstrates CNP2V2TT sing crystal is a promising highly emissive red-emitting material with confined emitting properties for optoelectronic and photonic applications.
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| Strategy for Future Research Activity |
In our future work, we will futher propel our work in two aspects:
First, we will introduce not only intermolecular interaction, but also intramolecualr charge transfer and/or proton transfer into the molecular aggregate so as to develop new RGB luminescenct molecular crystal with high luminescence and conductivity for the optoelectronic and photonic applications.
Second, we will try to extend the luminescent region of molecualr crystal from RGB region to deep red/near infared region due to deep red/near infared molecular solid is very limited and it's very important for the development of optoelecgronic and photonic application such as bioimaging and laser.
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