Fabrication of new silver-type compound solar cells

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K14551
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Energy engineering
• Research Institution: Miyakonojo National College of Technology
• Principal Investigator: Akaki Yoji 都城工業高等専門学校, 電気情報工学科, 准教授 (10321530)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 化合物太陽電池 / 硫化物 / 銀錫硫化物

Outline of Final Research Achievements

The goal of this study was to fabricate new silver-containing solar cells. Therefore, high quality Ag8SnS6 thin films were prepared. It was determined that to prepare high-quality thin films, the following conditions were essential: substrate temperature, two-step annealing after evaporation, Ag/Sn ratio of thin films, and the amount of antimony doping of thin films. (Cu,Ag)2SnS3 solar cells, which dissolved silver at 5% in Cu2SnS3, achieved an open-circuit voltage of 244 mV, short-circuit current density of 36.9 mA/cm2, fill factor of 0.45, and conversion efficiency of 4.07%. The abovementioned values were obtained because the open-circuit voltage and short-circuit current density increased the band gap energy and crystal grain, respectively, which helped dissolve silver in Cu2SnS3.

Free Research Field

電気電子材料

Academic Significance and Societal Importance of the Research Achievements

今回の研究成果により、高品質なAg8SnS6薄膜を成膜するためのポイント4点が明らかとなった。この成膜技術は、他のカルコゲナイド系化合物半導体にも転用できる技術と考えられるため、例えば、今後、研究の進展が期待されるAg8GeS6やAg2GeS3、Ag8SiS6、Ag2SiS3などの材料に活用できるため、その学術的意義は大きい。また、(Cu,Ag)2SnS3薄膜太陽電池で4%を超えたことにより、次世代の太陽電池として期待されているCu2ZnSnS4やCu2SnS3太陽電池の高効率化に向けた指針の一つとして利用できる可能性があり、環境・エネルギー問題解決のため、社会的にも大きな意義がある。