Two novel D-A-Ar-type small molecules of TPA-DPP-P and TPA(DPP-P)(2) were synthesized and characterized, in which triphenylamine (TPA), diketopyrrolopyrrole (DPP) and phenanthrene (P) were used as the donor (D) core, acceptor (A) arm, and enlarged pi-system of polycyclic arene (Ar) terminal. Their absorptive, electro-chemical, thermal, and photovoltaic properties were preliminary investigated. Significantly improved photo-physical and photovoltaic performances were observed for both small molecules containing the planar P terminal in comparison with those for their parent D-A-type molecule of TPA-DPP. The highest power conversion efficiency (PCE) of 3.42% and a maximum short-circuit current density (J(sc)) of 9.2 mA/cm(2) were obtained in the solution-processed TPA(DPP-P)(2)-based solar cells using [6,6]-phenyl-C-71-butyric acid methyl ester (PC71BM) as acceptor. The PCE and Jsc values are 8.76 and 4.97 times higher than those of the TPA-DPP-based cells, respectively. It indicates that appending the enlarged p-system of the planar P terminal and incorporating the DPP-P arm into D-A-type small molecule are efficient approaches to improve photo-physical and photovoltaic performances for its resulting molecules. (C) 2014 Elsevier B. V. All rights reserved.