2007 Fiscal Year Final Research Report Summary
Single-Molecule Optical Memory using High-performance Photochromic Diarylethenes
| Project/Area Number |
15105006
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| Research Category |
Grant-in-Aid for Scientific Research (S)
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| Allocation Type | Single-year Grants |
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| Research Field |
Functional materials/Devices
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| Research Institution | Rikkyo University (2007)
Kyushu University (2003-2006) |
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Principal Investigator |
IRIE Masahiro Rikkyo University, Department of Chemistry, Professor (30001986)
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| Co-Investigator(Kenkyū-buntansha) |
FUKAMINATO Tsuyosi Kyushu University, Graduate School of Engineering, Research Associate (80380583)
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| Project Period (FY) |
2003 – 2007
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| Keywords | Single-molecule spectroscopy / Photochromism / Fluorescence / Diarylethene / Confocal microscope |
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| Research Abstract |
The ultimate goal of optical memory is to store optical information in each molecule. As the first step to the single-molecule optical memory, we carried out the synthesis of fluorescent photochromic molecules suitable for the optical memory and measured the photo-switching of fluorescence from the single molecules. The photochromic molecule should exhibit the following performance ; high photo-switching efficiency, a fatigue resistant property and a high fluorescent quantum yield. It is also required to reveal the detailed mechanism of single-molecule photochemistry. The results are as follows.
(1) Fluorescent photochromic molecules having a fluorescent anthracene or perylene unit and a photochromic diarylethene unit were synthesized. When the two units are connected by an adamantyl group, the molecules exhibit efficient photo-switching performance and high fluorescent quantum yields. Molecules which show electron-transfer fluorescent quenching were also prepared.
(2) The above newly synthesized molecules were dispersed in various polymer matrices and the photo-switching of fluorescence from the single molecules was measured. The fluorescence showed a digital photo-switching in two states and the response times(on and off times) were found to show a broad distribution. The distribution of the response times was studied theoretically in detail and attributed to local minima in both ground and excited energy diagrams. This finding surely provides a new insight into the photochemistry in polymer matrices.
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