Cu2SnS3 thin-film solar cells without rare metal

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K04607
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 21060:Electron device and electronic equipment-related
• Research Institution: Ritsumeikan University
• Principal Investigator: Minemoto Takashi 立命館大学, 理工学部, 教授 (80373091)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 太陽電池 / 化合物薄膜 / 太陽光発電

Outline of Final Research Achievements

In this study, the impact of ramp-up and hold times during the growth of Cu2(Sn,Ge)S3 (CTGS) light-absorbing layers on the CTGS layer and solar cell performance was examined. When the peak temperature was set at 510°C, with a ramp-up time of 30 minutes and a hold time of 60 minutes, we observed an increase in the crystal grain size of the CTGS. Using the same sample to fabricate a solar cell, the highest conversion efficiency of 5.47% was achieved. Meanwhile, when we applied (Zn,Mg)O:Al, which has superior optical properties, as a transparent conductive oxide layer to the solar cell and varied the Mg/(Mg+Zn) ratio, the efficiency increased by 1-2% in absolute value in the range of 0.14-0.36 compared to the case without Mg addition. This increase is believed to be due to the widening of the bandgap of ZMO and the reduction of the conduction band discontinuity.

Free Research Field

太陽電池

Academic Significance and Societal Importance of the Research Achievements

本研究は、元素制約の可能性の小さい汎用元素を用いたCu2SnS3をベースとした薄膜太陽電池の高効率化に関するものです。本研究の成果は、高効率化に有用な、結晶品質の向上の方法やデバイス構造の改善に関するものである。特に、従来のZnOよりも紫外線領域で透過率の高いZnMgO系透明電極を用いることで効率向上を達成できることを示しており、これは他の太陽電池にも適用でき、学術的意義がある。太陽電池の実用化には高効率化が必要であり、これは太陽電池によるクリーンエネルギーの利用拡大に貢献する可能性があるという点に社会的意義がある。