| Project/Area Number |
08454224
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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 |
機能・物性・材料
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| Research Institution | Osaka University |
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Principal Investigator |
SHIROTA Yasuhiko Osaka University, Faculty of Engineering, Professor, 工学部, 教授 (90029091)
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| Co-Investigator(Kenkyū-buntansha) |
NAKANO Hideyuki Osaka University, Faculty of Engineering, Research Associate, 工学部, 助手 (00222167)
NOMA Naoki Osaka University, Faculty of Engineering, Research Associate, 工学部, 助手 (70208388)
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| Project Period (FY) |
1996 – 1997
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| Keywords | Molecular Glass / Starburst Molecule / Glass-transition Temperature / Crystal Structure / Charge Transport / Photochromism / Positron Annihilation / Electroluminescent Device |
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| Research Abstract |
For the purpose of creating molecular glasses, novel pi-electron starburst molecules and other pi-electron systems were designed and synthesized. They were found to readily form stable amorphous glasses with relatively high glass-transition temperatures. The relationship between molecular structures and glass-forming properties, and the stability and glass-transition temperature was investigated. X-Ray crystal structure analyzes of several compounds which form amorphous glasses provided information on the relationship between molecular structure and glass-forming property.
Charge transport in the molecular glass was investigated. Hole drift mobilities of several molecular glasses were determined and temperature and electric-field dependences of the hole drift mobility in the molecular glass were analyzed. As a result, valuable information on the relationship between molecular structure and charge transport properties was obtained. In addition, negative-electric field dependence of hole drift mobility was observed for the first time for the molecular glass.
Photochromism of an azobenzene derivative dispersed in a molecular glass was investigated in comparison with that dispersed in polystirene. In addition, positron annihilation lifetime in the molecular glass was determined. The results suggested that the local free volume in the molecular glass is smaller than that in polymer glasses.
Organic electroluminescent devices using molecular glasses were fabricated and their performances were investigated. Exciplex formation at the interface between hole- and electron-transport layrs was studied. It was shown that the emission color the device can be turned by using the exciplex emission.
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