Naphtho[1,2-b:5,6-b]dithiophene-based conjugated polymer as a new electron donor for bulk heterojunction organic solar cellsElectronic supplementary information (ESI) available: Detailed descriptions of synthetic procedures, structural characterization, and device fabrication for OFET and solar cell and figures showing the NMR spectra, GPC, TGA curve, DSC thermogram, CV, TFT curves, JV curves (1:1 to 1:4 w/w), and AFM images. See DOI: 10.1039/c2py00424k

We report for the first time the synthesis and photovoltaic application of a naphtho[1,2- b :5,6- b ]dithiophene (NDT) containing donoracceptor conjugated copolymer. The combination of a thiophene-bridge NDT building block with a quinoxaline acceptor unit results in a new copolymer that has an optical band gap of 1.77 eV, a HOMO level of 5.24 eV, and a hole mobility of 5.0 10 5 cm 2 V 1 s 1 . Preliminary characterization of the bulk-heterojunction solar cell device exhibits a PCE of around 1.5%. The synthesis and photovoltaic performances of the first naphtho[1,2- b :5,6- b ]dithiophene-based donoracceptor conjugated polymer are reported.