[19a-P5-1~38] 12.5 Organic solar cells

△ [19a-P5-8] Controlling open-circuit voltage of organic solar cells by introducing fluorine-containing substituents

〇Seiichi Furukawa^1,2, Komiyama Hideaki^2,3, Takuma Yasuda^1,2,3 (1.Grad. Sch. of Eng., Kyushu Univ., 2.INAMORI Frontier Research Center, Kyushu Univ., 3..I2CNER, Kyushu Univ.)

Keywords:Organic solar cells,low-bandgap donor materials,open-circuit voltage

In this study, we tried to increase open-circuit voltage (V_oc) of organic solar cells by introducing fluorine-containing substituents with different electron-withdrawing properties to a donor material, BDT-DPP, which we have already developed. As a result, V_oc can be increased due to the decrease of HOMO levels of the donor materials by introducing fluorine-containing substituents. In addition, we found the liner relationship between V_oc values and Hammett constant of fluorine-containing substituents. That is, systematic control of V_oc values can be achieved as kinds and positions of introduced fluorine-containing substituents. Also, carrier mobilities and molecular orientation in thin films were investigated by Space-Charge-Limited Current (SCLC) technique and Grazing-Incidence Wide-Angle X-ray Scattering (GI-WAXS) measurement, respectively. The effect of fluorine-containing substituents to the morphology of thin films and device characteristics were investigated.