Distribution of partial charge density close to the edge of conduction band for (A) V_Zn″-rich one-unit-cell ZnIn₂S₄ layers slab and (B) V_Zn″-poor one-unit-cell ZnIn₂S₄ layers slab in the [001] orientation. The unit cell structure of (C) V_Zn″-rich one-unit-cell ZnIn₂S₄ layers slab and (D) V_Zn″-poor one-unit-cell ZnIn₂S₄ layers slab in the [001] orientation. (E) Scheme for the photocatalytic CO₂ reduction into CO on the V_Zn″-rich one-unit-cell ZnIn₂S₄ layers. Ultrafast TA spectroscopy of (F) V_Zn″-rich one-unit-cell ZIS layers and (G) V_Zn″-poor one-unit-cell ZIS layers. (H) Surface photovoltage spectra and (inset) corresponding phase spectra of BiVO₄ layers and (I) the field-induced surface photovoltage spectra under different external electric fields. (A–G) Adapted with permission from Ref. [84], copyright 2017 American Chemical Society; (H–I) adapted with permission from Ref. [86], copyright 2017 American Chemical Society.