2007 Fiscal Year Final Research Report Summary
Control on the optical properties of organic-inorganic semiconductors with nano-quantum-structures by external fields
| Project/Area Number |
16310066
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Nanostructural science
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| Research Institution | University of Tsukuba |
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Principal Investigator |
MATSUISHI Kiyoto University of Tsukuba, Graduate Scholl of Pure and Applied Sciences, Associate Professor (10202318)
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| Co-Investigator(Kenkyū-buntansha) |
ONARI Seinosuke University of Tsukuba, Graduate School of Pure and Applied Sciences, Professor (70015824)
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| Project Period (FY) |
2004 – 2007
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| Keywords | Nano-Structured Semiconductors / Quantum Dot / High-Pressure Properties / Organic-Inorganic Hybrid Materials / Optical Properties / Spectroscopy / Structursl Analysee / Electronic States |
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| Research Abstract |
We have studied the structural, optical, and electronic properties of multi-quantum well/wire/dot materials of the self-organized organic inorganic complexes under external fields such as pressure. In this study, we have attempted to control the optical properties by tuning external fields.
The quantum dot (QD) crystal, (CH_3NH_3)_4PbI_6・2H_<2>O, which is composed of isolated【PbI_6^<4-> QDs bridged by methylamine ions and water molecules to form a 3D superlattice structure, exhibits 10.2 Gpa of bulk modulus and a structural phase transition at 4.5 Gpa. We found that the pressure dependences of the HOMO-LUMO transition energy of 【PbI_6】^<4-> QDs and its Stokes shift were different in the low-and high-pressure phases. Information of the electronic and structural interactions between QDs and between a QD and a methylamine molecule was obtained from high-pressure data. We also found a structural transformation from the QD superlattice to quasi-3D connection of PbI_6 QDs around 60℃ in vacuum due to the removal of water molecules from the crystal, which involved a remarkable change in the optical properties.
We have obtained information of the bulk modulus, the anisotropic compression and the pressure dependence of optical properties of the organic-inorganic quantum wire (QW) crystals, C_5H_<10>NH_2PbI_3, (C_<12>H_<14>N_2) Pb_2I_6 and [NH_2C (I)=NH_2]_3PbI_5. Especially, we have found that the probability of the charge transfer transition from QWs to the organic molecules in (C_<12>H_<14>N_2) Pb_2I_6 was able to be tuned by applying pressure.
For CdSe QDs, we have found for the first time that bulk modulus and deformation potential of the HOMO-LUMO transition energy change reciprocally with the size of QDs. The pressure coefficient of emission energy was different between TOPO-CdSe QD and HAD-CdSe QD samples, indicating that the states of interface between organic molecules and QDs play an important role on the optical response under high pressure.
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Research Products
(70 results)
