Growth and characterization of nanospikes decorated ZnO sheets and their solar cell application

This work reports the synthesis of nanospikes decorated ZnO sheets on the electrodeposited ZnO seeded fluorine doped tin oxide (FTO) substrates through the hydrothermal method at 90 °C and its application as photoanode for the efficient dye sensitized solar cells (DSSCs). The unique nanospikes decorated ZnO sheets were comprised of nanospikes with the average diameter of ∼80–100 nm and the sheets of several nanometers. The ZnO nanospikes were decorated on either one side or the both side of the single ZnO sheets (thickness ∼50–60 nm). The X-rays diffraction and UV–Vis spectroscopy results revealed that the grown nanospikes decorated ZnO sheets exhibited well crystalline with typical wurtzite hexagonal phase of ZnO nanostructures. A growth mechanism was proposed to investigate the formation of the grown nanospikes decorated ZnO sheets. The photoanode showed the relatively high dye absorption which was derived from the larger surface area of the grown nanospikes decorated ZnO sheets. The solar-to-electricity conversion efficiency of ∼2.51% with the high short circuit current (JSC) of 6.07 mA/cm2 was attained by DSSC fabricated with nanospikes decorated ZnO sheets photoanode. The enhanced performance might credit to the high charge collection and the fast electrons transfer at the interfaces of ZnO and the electrolyte layer due to the high dye absorption over the surface of ZnO leading to high light harvesting.

► The nanospikes decorated ZnO sheets are synthesized by the hydrothermal method at 90 °C. ► The grown nanospikes decorated ZnO sheets exhibit well crystalline typical wurtzite hexagonal phase of ZnO nanostructures. ► A growth mechanism shows the formation of nanospikes decorated ZnO sheets. ► The photoanode of nanospikes decorated ZnO sheets displays relatively high dye absorption. ► Fabricated DSSC achieves the solar-to-electricity conversion efficiency of ∼2.51%.