Poly(4,8‐bis(2‐ethylhexyloxy)benzo[1,2‐b:4,5‐b′]dithiophene vinylene): Synthesis, optical and photovoltaic properties

Abstract

Abstract A new benzodithiophene (BDT)‐based polymer, poly(4,8‐bis(2‐ethylhexyloxy)benzo[1,2‐b:4,5‐b′]dithiophene vinylene) (PBDTV), was synthesized by Pd‐catalyzed Stille‐coupling method. The polymer is soluble in common organic solvents and possesses high thermal stability. PBDTV film shows a broad absorption band covering from 350 nm to 618 nm, strong photoluminescence peaked at 545 nm and high hole mobility of 4.84 × 10 −3 cm 2 /Vs. Photovoltaic properties of PBDTV were studied by fabricating the polymer solar cells based on PBDTV as donor and PC 70 BM as acceptor. With the weight ratio of PBDTV: PC 70 BM of 1:4 and the active layer thickness of 65 nm, the power conversion efficiency of the device reached 2.63% with V oc = 0.71 V, I sc = 6.46 mA/cm 2 , and FF = 0.57 under the illumination of AM1.5, 100 mW/cm 2 . © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1822–1829, 2010