A phenylenevinylene-thiophene-phenyleneethynylene copolymer: synthesis, characterization, and photovoltaic properties

A phenylenevinylene-thiophene-phenyleneethynylene copolymer, poly{[1',4'-bis-(thienyl-vinyl)-1-2methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene-vinylene-alt-1,4-dioctyloxyl-phenyleneethynylenel(PTPPV- PPE), was synthesized by the Sonogashira Pd-catalyzed cross-coupling reaction. The copolymer possesses higher thermal decomposition temperature (T-d = 382 degrees C) compared with poly{[1',4'-bis(thienyl-vinyl)1-2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene-vinylene} (PTPPV). The absorption and photoluminescence (PL) peaks of PTPPV-PPE solution and solid film locate in between those of the homopolymers of PTPPV and poly(1,4-dioctyloxyl-phenyleneethynylene) (PPE), and closer to that of PTPPV. Photovoltaic cell was fabricated based on the blend of PTPPV-PPE and PCBM with a weight ratio of 1:1. The primary result shows an open circuit voltage (V-oc) of 0.72 V which is higher than that of the PTPPV (0.67V), and a power conversion efficiency (PCE) of 0.3% under the illumination of AM1.5, 100 mW/cm(2) which is much better than that of PPEs. Copyright (C) 2008 John Wiley & Sons, Ltd.