Naphtho[1,2-b:5,6-b′]dithiophene Based Two-Dimensional Conjugated Polymers for Highly Efficient Thick-Film Inverted Polymer Solar Cells

Two-dimensional conjugated zigzag naphthodithiophene was used for construction of novel polymer photovoltaic materials. Two novel copolymers based on zigzag naphthodithiophene and alkylthieno[3,4- c ]pyrrole-4,6-dione inserted with different alkyl substituted thiophene as bridges have been designed and synthesized (PzNDTT-TPD1 and PzNDTT-TPD2, respectively). The best power conversion efficiency of a PzNDTT-TPD1-based device reaches 7.50% at an active layer thickness of 203 nm and the device performances of PzNDTT-TPD1-based polymer solar cells are all above 6.4% with active layer thickness variations from 141 to 244 nm, suggesting that it is very suitable for the fabrication of high performance, large area solution-processed polymer solar cells.