Organic photovoltaic (OPV) devices with the general structure of ITO/PEDOT: PSS (60nm)/m-MTDATA (40nm)/(OXDPybm)Ln(DBM)3 (20 nm)/LiF (1 nm)/Al (120 nm) are demonstrated by utilizing (OXD-Pybm)Ln(DBM)3 (Ln = Pr, Sm, Eu, Gd, and Tb) as electron acceptors and 4,4',4"-tris(N-(3-methylphenyl)-N-phenylamino) triphenylamine (m-MTDATA) as an electron donor. The performances of these devices are experimentally improved by the introduction of 2,5-diphenyl-1,3,4-oxadiazole (OXD) group into the electron acceptors. Besides, it is found that (OXD-Pybm)Pr(DBM)3 based device holds the potential application in UV-1ight detection due to the absence of dark current with the compensatory voltage lower than 1.65 V. The highest power conversion efficiency (eta) and the maximum fill factor (FF) among these OPV devices are 2.60% and 0.33, respectively. (C) 2007 Elsevier B.V. All rights reserved.