Fluorination effects of A-D-A-type small molecules on physical property and the performance of organic solar cell

Chen, K.-W.K.-W.ChenLin, L.-Y.L.-Y.LinLi, Y.-H.Y.-H.LiLi, Y.-Z.Y.-Z.LiNguyen, T.P.T.P.NguyenBiring, S.S.BiringLiu, S.-W.S.-W.LiuWong, K.-T.K.-T.Wong2019-07-312019-07-312018https://www.scopus.com/inward/record.uri?eid=2-s2.0-85034845559&doi=10.1016%2fj.orgel.2017.11.021&partnerID=40&md5=4c4f3e9b73fbeb656569f9ed28ffa209https://scholars.lib.ntu.edu.tw/handle/123456789/415829Four new molecules with acceptor-donor-acceptor (A-D-A) configuration where cyclopenta[2,1-b:3,4-b′]dithiophene (CPDT) as the electron-donating core connecting to cyano(CN)-substituted 2,1,3-benzothiaidiazole (BT) as electron-withdrawing end groups are reported. With the same acceptor CN-BT, we found that CPDT can serve as a better donor as compared to that of dithieno[3, 2-b: 2′, 3′-d]silole (DTS) to give stronger intramolecular charge transfer (ICT) character and therefore better light harvesting ability. The number and orientation of F-substitution on the BT ring, giving a clear structure-property relationship, can subtly manipulate the physical characteristics. These A-D-A type molecules were employed as electron donor in conjunction with C70 as the electron acceptor in vacuum-deposited bulk heterojunction (BHJ) small-molecule organic solar cells (SMOSCs). Among them, the device based on CBCIF containing BT ring with one F group directing toward the CPDT core gave the best device performance with a power conversion efficiency of 4.94% with Jsc of 10.16 mAcm−2, Voc of 0.98 V, fill factor (FF) of 0.50. The superior device characteristics were attributed to the suitable morphology of the donor/C70 film. © 2017 Elsevier B.V.2,1,3-Benzothiaidiazole; A-D-A donor; Fluorination effect; Organic photovoltaics; Small-molecule organic solar cell[SDGs]SDG7Charge transfer; Electrons; Fluorination; Halogenation; Heterojunctions; Molecules; Photovoltaic effects; Solar cells; Solar power generation; 2,1,3-Benzothiaidiazole; A-D-A donor; Fluorination effect; Organic photovoltaics; Small-molecule organic solar cells; Organic solar cellsFluorination effects of A-D-A-type small molecules on physical property and the performance of organic solar celljournal article10.1016/j.orgel.2017.11.0212-s2.0-85034845559