Produce of carbon nanotube/ZnO nanowires hybrid photoelectrode for efficient dye-sensitized solar cells

In this paper, we have successfully grown high quality CNT film on FTO substrate followed by ZnO NWs growth on top of CNT film by hydrothermal growth method. Dye-sensitized solar cells (DSSC) were fabricated utilizing carbon nanotube (CNT)/ZnO nanowire (NW) hybrid photoelectrode. By using the CNT/ZnO NWs in DSSC as photoanodes, it was shown that the hybrid structure is promising alternative in conventional DSSCs becuase CNT and ZnO show perfect work-function alignment, high surface area and superior optoelectronic properties. The fabricated DSSC shows a solar cell efficiency of η = 5.55%, which is 20% higher than the cell fabricated without CNT layer. It was demonstrated that the incorporated CNT caused both enhancement of N719-dye absorption on the surface of hybrid structures and significant increase of short circuit current density (Jsc) due to longer electron lifetime. Current density (Jsc)-Voltage characterization indicates the enhancement of the power conversion efficiency of the solar cell mostly due to the increase of carrier density by CNT, decrease in carrier recombination and increase devices voltage. Based on the above results, we were able to obtain almost the highest power conversion efficiency among ZnO based DSSCs.