Research on high-efficiency intermediate band tandem solar cells based on dilute nitride alloys

2020 Fiscal Year Final Research Report

• Project/Area Number: 17KK0127
• Research Category: Fund for the Promotion of Joint International Research (Fostering Joint International Research)
• Allocation Type: Multi-year Fund
• Research Field: Design and evaluation of sustainable and environmental conscious system
• Research Institution: Saitama University
• Principal Investigator: Shuhei Yagi 埼玉大学, 理工学研究科, 准教授 (30421415)
• Project Period (FY): 2018 – 2020
• Keywords: 中間バンド型太陽電池 / 希釈窒化物混晶半導体 / 分子線エピタキシー

Outline of Final Research Achievements

Tandem solar cells consisting of two stacked intermediate band solar cells (IBSCs) were investigated. Based on the detailed balance model, the conversion efficiency for various band gap combinations was calculated. As a result, it was found that the conversion efficiency of 53% under 1 Sun irradiation and 73% under maximum light concentration can be obtained by selecting the appropriate band gap combination. InGaAsN and GaPN alloys were proposed as candidate materials for the bottom IBSC and top IBSC, respectively. IBSCs using those alloys as the absorbing layer were fabricated and quantitatively evaluation of the current generation originating from the two-step photoabsorption through the intermediate band was carried out by measuring current response under multiple wavelength light irradiation.

Free Research Field

半導体工学

Academic Significance and Societal Importance of the Research Achievements

持続可能な社会の実現に向けて、太陽後発電をはじめとする再生可能エネルギーの普及は世界的な課題となっている。本研究課題では、次世代の高効率化技術として着目されている中間バンド型太陽電池について、複数セルの積層化により更なる高効率化の可能性を示すとともに、材料選択の指針を示した。セル変換効率の向上は発電コストの低下に必須であり、本研究で得られた成果は将来的な太陽光発電の普及促進に資するものである。