[11p-S221-1~13] 12.5 Organic solar cells

△ [11p-S221-10] Thickness Dependence of Fill Factors in Solar Cells Based on Fluorinated Naphthobisthiadiazole Polymers

〇(DC)Tomohiro Fukuhara¹, Masahiko Saito², Yasunari Tamai^1,3, Hyung Do Kim¹, Itaru Osaka², Hideo Ohkita¹ (1.Kyoto Univ., 2.Hiroshima Univ., 3.JST PRESTO)

Keywords:polymer solar cell, fill factor, bimolecular recombination

Polymer solar cells exhibit low FF with a thick active layer. In this study, we performed transient photovoltage (TPV) and transient photocurrent (TPC) measurements and evaluated bimolecular recombination losses in solar cells based on naphtho[1,2-c:5,6-c’]bis[1,2,5]thiadiazole (NTz)-based polymers. In these systems, the position of fluorination impacts the thickness dependence of FF. The results suggested that it is required for achieving high FF even with a thick active layer not only to suppress bimolecular recombination but also to maintain desirable film morphology for charge transport.