| Project/Area Number |
20K04293
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 19010:Fluid engineering-related
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| Research Institution | Ritsumeikan University |
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Principal Investigator |
WELLS John C. 立命館大学, 理工学部, 教授 (60301644)
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| Co-Investigator(Kenkyū-buntansha) |
河野 悠 立命館大学, 理工学部, 助教 (40822838)
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| Project Period (FY) |
2020-04-01 – 2023-03-31
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| Project Status |
Completed (Fiscal Year 2022)
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| Budget Amount *help |
¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2022: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2021: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2020: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
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| Keywords | Silicon / Hollow spheres / Hollow jet method / Solidification / Silicon. / Hollow spheres. / Hollow jet method. / Hollow / silicon / millisphere / solidification / horn / hollow metal spheres / hollow jet instability / two phase simulations / hollow Si spheres / solar cells / dropping method / coaxial jet flow / numerical simulation |
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| Outline of Research at the Start |
By extending the dropping method for production of solid metal spheres to a hollow jet of molten silicon (Si), we aim to develop a simple method of mass-producing hollow Si spheres that are suited to application as photovoltaic cells.
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| Outline of Final Research Achievements |
Hollow silicon millispheres have been fabricated using a hollow coaxial jet for the first time.
Silicon was melted in a graphite crucible at 1823 K, then ejected from the annulus of a coaxial nozzle as argon gas was injected from an inner nozzle whose inner and outer diameters are 0.4 mm and 1 mm respectively. Sphere diameters were 1 - 2 mm with spherical outer surfaces, and the frequency of formation was approximately 145 Hz.
The wall thicknesses varied gradually between antipodes. The interior surfaces were somewhat non-spherical, with horn-like structures where the wall was thicker, most likely owing to silicon expansion as solidification finishes. This is the first report of such a “horn expansion structure” observed on a concave substrate.
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| Academic Significance and Societal Importance of the Research Achievements |
Hollow silicon millispheres have been fabricated using a hollow coaxial jet for the first time. It is hoped that such hollow structures could permit higher photovoltaic energy efficiency that the solid spheres that are currently used for spherical silicon solar cells.
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