• polymer solar cells;
  • vanadium oxide;
  • hole-extracting layer;
  • solution-processed


Here we reported the fabrication of efficient polymer solar cells from regioregular poly(3-hexylthiophene) (P3HT):fullerene derivative [6,6]-phenyl-C61 butyric acid methyl ester (PC61BM) mixtures, in which solution-processed vanadium oxide (VOx) was used as a hole-extracting layer (HEL). The obtained devices exhibited a high power conversion efficiency of 3.96%, and can be enhanced to 4.06% and 4.16%, respectively, when two types of PEDOT:PSS with different conductivities were used in conjunction with the VOx layer. All the VOx-based devices showed a high fill factor (FF) over 70%, which was ascribed to efficient hole extracting efficiency associated with the solution-processed VOx hole-extracting layer. The origins of the improvement were also studied by transmission spectra, atomic force microscope (AFM), and capacitance-voltage characteristics.