| Project/Area Number |
17360008
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Applied materials science/Crystal engineering
|
|---|
| Research Institution | The University of Tokyo |
|---|
Principal Investigator |
SHIMADA Toshihiro The University of Tokyo, School of Science, Professor (10262148)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
長谷川 哲也 東京大学, 大学院・理学系研究科, 教授 (10189532)
HITOSUGI Taro Tohoku University, WPI Advanced Institute for Materials Research, Associate Professor (90372416)
|
|---|
| Project Period (FY) |
2005 – 2007
|
| Project Status |
Completed (Fiscal Year 2007)
|
| Budget Amount *help |
¥15,980,000 (Direct Cost: ¥14,900,000、Indirect Cost: ¥1,080,000)
Fiscal Year 2007: ¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000)
Fiscal Year 2006: ¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2005: ¥7,700,000 (Direct Cost: ¥7,700,000)
|
|---|
| Keywords | Alq3 / ferroelectrics / pyroelectrics / optical excitation / intramolecular energy transfer / GASH / oxides / nanoparticles / Alq / 結晶成長 / 超薄膜 / 偏光解消 / 電場 / レーザーアブレーション / 巨大光起電力 / 光アクチュエータ |
|---|
| Research Abstract |
We investigated new phenomena induced by optical excitation of ferro and pyro electric materials. Materials for this purpose are also searched by using doping. First, we studied the growth of polar semiconductor molecule Alq3 thin films with laser irradiation. We found that the molecular crystal domains become aligned with laser polarization. In order to investigate the mechanism of this phenomenon, we varied the growth conditions and the polarization of the laser. Based on the experimental results, we constructed a model as follows. It is known that giant photovoltage occurs by photoexcitation of ferroelectrics. If similar phenomenon occurs, then it is presumable that polar molecules are attracted by the giant electric field and becomes aligned in one direction. Second, we investigated angular distribution of the laser-aligned epitaxial films but no dependence on the polarization of the excitation lights were observed. We collaborated with a ultrafast laser laboratory and fo0und tha the intramolecular energy transfer occurs very quickly, which can explain the polarization dependence. This result indicates that polar emission of organic LED is not expected from Alq3. It further indicates that the laser-alignment, in the thin film growth is not induced by ultrafast phenomena but by rather static mechanism, which is consistent with our model. As for the materials development, we attempted doping of chromium to ferroelectric GASH and confirmed that the ferroelectricity is not broken by doping. We also studied doping to oxide nanoparticles by laser ablation in dopant solutions, doping of nanocrystals to polymers. We confirmed that doping occurs with high efficiency.
|
