1997 Fiscal Year Final Research Report Summary
Organic electroluminescence cells fabricated by a novel laser ablation scheme with selective thin film growth
| Project/Area Number |
08555087
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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 | 展開研究 |
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| Research Field |
電子デバイス・機器工学
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| Research Institution | Keio University |
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Principal Investigator |
KANNARI Fumihiko Keio University, Faculty of Science and Technology, Associate Professor, 理工学部, 助教授 (40204804)
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| Co-Investigator(Kenkyū-buntansha) |
YAMAGUCHI Shigeru Tokai University, Faculty of Science, Associate Professor, 理学部, 助教授
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| Project Period (FY) |
1996 – 1997
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| Keywords | organic thin films / laser ablation deposition / electroluminescence cell / electric poling / copper pthalocyanine |
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| Research Abstract |
1.Crystallinity Improvement for Organic Thin Films Fabricated via Laser Ablation
Slight elevation of substrate temperature can induce significant improvement on the thin film crystallinity fabricated via laser ablation deposition because of the migration enhancement. Very weak HeNe laser irradiation at -1mW/cm^2 can also contribute to enhance the surface migration resulting in better crystalline CuPc thin films, which exhibits significant absorption at the visible wavelength. When substrate crystal field is so strong that thin film deposited on the substrate tends to align along a defined direction, this temperature effects enhance the natural orientation affected by the substrate.
On the other hand, molecules that hold high electric polarizability can be controlled by external electric field during the thin film formation on a substrate. The crystallinity of CuPc thin films fabricated on a Si substrate is drastically improved with an external electric field. However, he effect of crystal field is much higher than this electric poling effect during the thin film formation.
2.Electric Characteristics of CuPc Thin Films
Electric conductivity was measured for CuPc thin films with various crystallinities. Amorphous thin films exhibit better conductivity in the direction of thickness, which is better for electroluminescence devices, while the crystalline thin films deposited under electric field show higher conductivity along the film surface. We measured a near field emission pattern of CuPc/Alq3 electroluminescence cells, of which crystallinity was locally improved with HeNe laser irradiation. However, the difference in the conductivity is still not high enough to generate localized current flow.
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