Organic solar cells with high mobility materials

2021 Fiscal Year Final Research Report

• Project/Area Number: 18K14115
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 29010:Applied physical properties-related
• Research Institution: Institute for Molecular Science
• Principal Investigator: Izawa Seiichiro 分子科学研究所, 物質分子科学研究領域, 助教 (60779809)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Keywords: 有機太陽電池 / 界面 / 移動度 / 電荷分離 / 電荷再結合

Outline of Final Research Achievements

Reducing an energy loss in output voltage are critically important for further enhancing the efficiency of organic solar cells (OSCs). Here, we report that the OSCs with high charge mobility and highly crystalline donor (D) and acceptor (A) materials is able to reach open circuit voltage (VOC) close to theoretical limit and fill factor (FF) of near 0.8. The high crystallinity at the several molecular layers near to the D/A interface were important for realizing high VOC and FF. The reasons for high VOC and FF are that the highly crystalline D/A interface reduced the energy loss in output voltage related to the trap assisted recombination. Our results demonstrated that careful design of D/A interface enables us to approach high power conversion efficiency in OSCs close to theoretical limit of the single junction solar cells.

Free Research Field

有機光デバイス

Academic Significance and Societal Importance of the Research Achievements

本研究では発電が起こる界面近傍の結晶性を向上できれば、有機太陽電池の光電変換効率を高効率無機太陽電池と同等の水準まで向上できること、つまり有機太陽電池で効率20％超も実現可能であることを示した。今回の成果は界面の構造が制御しやすい二層型のモデルデバイスで得られたものだが、今後、界面面積が大きく実用的なデバイス構造である混合型の有機太陽電池でも、新たな材料開発により同様に界面近傍の結晶性を制御できれば、有機太陽電池の光電変換効率を大幅に向上につながると考えられる。