2013 Fiscal Year Annual Research Report
| Project/Area Number |
13F03392
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| Research Institution | The University of Tokyo |
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Principal Investigator |
磯貝 明 東京大学, 大学院農学生命科学研究科, 教授
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| Co-Investigator(Kenkyū-buntansha) |
YANG Quanling 東京大学, 大学院農学生命科学研究科, 外国人特別研究員
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| Keywords | quantum dot / cellulose nanofibril / fluorescence / Linear arrays |
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| Research Abstract |
Quantum dots (QDs) are luminescent nanocrystals made of semiconductor materials that are small enough to display quantum mechanical properties. If the size of the quantum dot is small enough that the quantum confinement effects dominate (typically less than 10 nm), the electronic and optical properties are highly tunable. Thus quantum dots of the same material, but with different sizes, can emit light of different colors. They have attracted much attention because of their wide applications in, for example, molecular imprinting, nanophotonics, nonlinear optical devices, solar cell, fluorescence probes, and UV-protective materials. The applications of QDs in the fields of biodiagnostics, bioanalytics, photonics and optoelectronics require combination of the QDs with polymers. In particularly, linear arrays of quantum dots are predicted to show localization effects for light traveling along the linear dimension. Thus the development of methods to obtain well-defined polymer-QD hybrid mat
… More
erials with tunable optical properties is an active field of research. Cellulose is the most abundant natural polymer on earth. Moreover, TEMPO-oxidized cellulose nanofibrils (TOCNs) are completely individualized cellulose nanofibers which have very small widths (3-4 nm), high aspect ratios (>250), high crystal moduli (130-150 GPa), high strength (2-6 GPa), high thermal stability (Tm > Td ~300°C), low coefficients of thermal expansion (0-6 ppm ^<k-1>), large surface areas (~800 m^2 ^<g-1>), and large number of carboxylate groups (~1.70 mmol ^<g-1>) on their surfaces. The large amount of anionic carboxylate groups on the TOCN surface are easy to attract QDs modified by cationic ligands. Therefore, TOCNs were used to prepare strongly luminescent nanocomposites with QDs in this work. TOCN-QD nanocomposites with linear arrays of QDs or homogenous arrays of QDs were both successfully prepared from TOCNs and amino-QDs or carboxyl-QDs. Both TOCN-QD dispersions and films showed good transparency under white light and strong luminescence under UV light. Carboxylic acid/amine salt formed between TOCNs and amino-QDs confired by FT-IR, leading to the attachment of QDs on TOCN surfaces. Some free carboxyl groups of TOCN were still present in the composites, resulting in the good dispersed state of them and good optical transparency of TOCN-QD nanocomposite films. Less
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| Current Status of Research Progress |
Current Status of Research Progress
1: Research has progressed more than it was originally planned.
Reason
Based on the objective of this research, TOCNs were used to prepare strongly luminescent nanocomposites with QDs. We sucessfully prepared TOCN-QD nanocomposites with linear arrays or homogenous arrays of QDs. Both TOCN-QD dispersions and films showed good transparency under white light and strong luminescence under UV light. Moreover, we clarified the interactions between TOCN and QD, indicating that carboxylic acid/amine salt formed between TOCNs and amino-QDs, leading to the attachment of QDs on TOCNs.
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| Strategy for Future Research Activity |
The future plans of this research are to prepare TOCN-QD nanocomposites with higher QD contents, to measure the fluorescence emission spectra of the TOCN-QD nanocomposites (emission wavelength, intensity, and quantum yield), and to measure the mechanical, thermal properties of the TOCN-QD nanocomposites.
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Research Products
(3 results)
