title: Star-shaped D-A small molecules based on diketopyrrolopyrrole and triphenylamine for efficient solution-processed organic solar cells.
abstract: Three star-shaped D-A small molecules, (P-DPP)(3)TPA, (4-FP-DPP)(3)TPA, and (4-BuP-DPP)(3)TPA were designed and synthesized with triphenylamine (TPA) as the core, diketopyrrolopyrrole (DPP) as the arm, and unsubstituted or substituted benzene rings (phenyl, P; 4-fluoro-phenyl, 4-FP; 4-n-butyl-phenyl, 4-BuP) as the end-group. All the three small molecules show relatively narrow optical band gaps (1.68-1.72 eV) and low-lying highest occupied molecular orbital (HOMO) energy levels (-5.09∼-5.13 eV), implying that they are potentially good electron donors for organic solar cells (OSCs). Then, photovoltaic properties of the small molecules blended with [6,6]-phenyl-C(61)-butyric acid methyl ester (PC(61)BM) as electron acceptor were investigated. Among three small molecules, the OSC based on (P-DPP)(3)TPA:PCBM blend exhibits a best power conversion efficiency (PCE) of 2.98% with an open-circuit voltage (V(oc)) of 0.72 V, a short-circuit current density (J(sc)) of 7.94 mA/cm(2), and a fill factor (FF) of 52.2%, which may be ascribed to the highest hole mobility of (P-DPP)(3)TPA.
authors: State Key Laboratory of Silicon Materials, MOE Key Laboratory of Macromolecular Synthesis and Functionalization, & Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, P R China.
authors: Jun-Ying
authors: JY
authors: Pan
authors: Li-Jian
authors: LJ
authors: Zuo
authors: Xiao-Lian
authors: XL
authors: Hu
authors: Wei-Fei
authors: WF
authors: Fu
authors: Mei-Rong
authors: MR
authors: Chen
authors: Lei
authors: L
authors: Fu
authors: Xiao
authors: X
authors: Gu
authors: Hang-Qi
authors: HQ
authors: Shi
authors: Min-Min
authors: MM
authors: Shi
authors: Han-Ying
authors: HY
authors: Li
authors: Hong-Zheng
authors: HZ
authors: Chen