Core-shell ZnO@CuInS2 hexagonal nanopyramids with improved photo-conversion efficiency

A soft chemical route has been employed to synthesize ZnO@CuInS2 (ZnO@CIS) core-shell hexagonal nanopyramids using 2-mercaptopropionic acid as a surface-functionalized agent. The core-shell formation was confirmed by the X-ray diffraction, high resolution transmission electron microscope and X-ray photoelectron spectroscopy characterizations. UV-visible absorption spectrum of the core-shell nanopyramids shows a red shift of the band edge of pure ZnO in the visible region along with broadening of the absorption spectrum. ZnO@CIS nanopyramids can be used as an antireflection coating on Silicon solar cell, exhibit lower reflectance and better light trapping ability than the Silicon solar cell with ZnO nanopyramids. Moreover higher photocurrent is obtained for the n-ZnO/n-CIS core-shell junction due to favorable band bending. The efficiency of the p-Si/n-ZnO solar cell (6.6%) is improved to 10% for p-Si/n-ZnO@n-CIS configuration.