Efficient photo charge transfer of Al-doped ZnO inverse opal shells in SnS2 photoanodes prepared by atomic layer deposition

Abstract The aluminum-doped zinc oxide (AZO) inverse opal shells (IOS) and tin disulfide (SnS2) as a core-shell heterojunction (AZO IOS/SnS2) photoanode for photoelectrochemical (PEC) water splitting was prepared by atomic layer deposition (ALD). The optimized AZO IOS/SnS2 yielded photocurrent density of 1.05 mA/cm2, which was 19 times higher than that of pure AZO IOS (0.054 mA/cm2) while about eight times as that of bare SnS2 film, whose individual photocurrent was 0.12 mA/cm2 in the neutral electrolyte. These results indicated the synergetic effect of AZO IOS when combined with low bandgap materials such as SnS2 for the formation of an appropriate heterojunction. This effect causes to collection of a majority of photoelectrons excited in the visible region of the solar spectrum to improve their PEC water splitting ability. Herein, we demonstrated the possible photocharge transfer model and the mechanism of PEC water splitting.