Investigation on Enhancement of Absorption and Improvement of Efficiency of Very-Thin Crystalline Silicon Solar Cells with Thickness of 10-20 µm

2018 Fiscal Year Final Research Report

• Project/Area Number: 17K14666
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Electron device/Electronic equipment
• Research Institution: Kyoto University
• Principal Investigator: Ishizaki Kenji 京都大学, 工学研究科, 助教 (40638524)
• Project Period (FY): 2017-04-01 – 2019-03-31
• Keywords: フォトニック結晶 / 薄膜太陽電池

Outline of Final Research Achievements

Solar photovoltaics in which inexhaustible solar energy is utilized will continuingly increase their importance. In this work, we aimed to build a foundation to improve efficiency with significantly thinning the thickness of Si to 10-20μm. The utilization of the large-area resonant effect of photonic crystals, which has periodic structure of the order of light wavelength, has been investigated. The structural optimization using genetic algorithm was performed and photo-current of 39.1mA/cm2 was numerically obtained in ~20μm-thick Si. Moreover, the studies on the fabrication method of thin-film cells and the structures/materials of their electrodes suggested the efficiency would be improved up to 17% combining the developed processing and designed structures.

Free Research Field

光量子電子工学

Academic Significance and Societal Importance of the Research Achievements

無尽蔵のエネルギー源である太陽光を活用した太陽光発電は、今後の社会においても、その重要性がますます増加すると考えられる。これまでの主流は、200μm前後の厚さの結晶シリコン太陽電池であったが、Si層を10～20μm級へと大幅に薄型化しつつも高い効率を得ることができれば、コスト低減、フレキシブル化による設置可能場所の拡大等、産業的な優位性が大幅に高まるものと期待される。本研究では、通常と比べて1/10程度の厚さの非常に薄い結晶Si層における光吸収を増大させることが可能であること等を示しており、今後の超薄型結晶Si太陽電池の高効率化に重要な指針を与えるものと位置付けられる。