[17p-G202-1~21] 12.5 Organic solar cells

△ [17p-G202-2] Charge-Transport and Photovoltaic Properties of Halogen-Substituted Narrow Bandgap Organic Semiconductors

〇(DC)Seiichi Furukawa¹, Hideaki Komiyama², Takuma Yasuda^1,2 (1.Grad.School of Eng, Kyushu Univ., 2.IFRC, Kyushu Univ.)

Keywords:organic semiconductors, organic solar cells, charge carrier mobility

In this study, we synthesized narrow-bandgap small molecules functionalized with several kinds of halogeno groups at the terminal, and evaluated the relationship between molecular structure and charge-transport property. As a result, we found that the chloro-functionalized material shows higher hole mobility in the thin film state. With such proper molecular engineering, the bulk heterojunction OSCs based on the halogenated molecules as donor materials demonstrated enhanced fill factors compared to that obtained with a non-halogenated one due to suppression of the bimolecular charge recombination. Among this series of donor materials, the monochloro-substituted donor material gave high fill factors of up to 67%, and achieved PCEs of 6.5%.