Next Generation Thin Film Solar Cell Material SnS: Pursuit of Solid State Chemistry for Homojunction

2021 Fiscal Year Final Research Report

• Project/Area Number: 18KK0133
• Research Category: Fund for the Promotion of Joint International Research (Fostering Joint International Research (B))
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 26:Materials engineering and related fields
• Research Institution: University of Yamanashi
• Principal Investigator: Yanagi Hiroshi 山梨大学, 大学院総合研究部, 教授 (30361794)
• Co-Investigator(Kenkyū-buntansha): 川西 咲子 東北大学, 多元物質科学研究所, 助教 (80726985) ; 鈴木 一誓 東北大学, 多元物質科学研究所, 助教 (60821717)
• Project Period (FY): 2018-10-09 – 2022-03-31
• Keywords: SnS / 太陽電池 / コンビナトリアル製膜

Outline of Final Research Achievements

The n-type SnS thin film was realized by optimizing the film deposition conditions using a combinatorial sputtering method at NREL (USA). N-type SnS thin film was realized by supplying atomic sulfur, which reduces the number of in-gap states. It was found that SnS solar cells are expected to have a high open-circuit voltage of ~0.7 V if the interface defects at the p-n interface are suppressed, according to the XPS measurements performed at TU Darmstadt (Germany). A prototype homojunction solar cell was fabricated by forming a p-type thin film on an n-type single crystal. The conversion efficiency of 1.4% was lower than that of existing heterojunction solar cells, but the open-circuit voltage was as high as 0.36 V, demonstrating the effectiveness of homojunction solar cells.

Free Research Field

無機材料科学

Academic Significance and Societal Importance of the Research Achievements

n型SnS薄膜実現のために本質的に重要な制御因子を解明し、解決手法を実証した意義は大きい。これに加えてSnS太陽電池における高Vocの実現可能性の科学的根拠を与えた。これらにより環境親和性が高く資源制約の少ない高効率SnSホモ接合薄膜太陽電池への道を拓いたことで、次世代太陽電池材料に新たな選択肢を提供した。