Light-harvesting efficiency and polychromatic radial optical generation rate. (a) Light-harvesting efficiency (LHE) of the as-grown and annealed ZnO/CdTe core-shell NW arrays at 300°C and 450°C for 1 h, respectively. (b) Maps of the polychromatic radial optical generation rate in ZnO/CdTe core-shell NW arrays plotted in both logarithmic (left) and linear (right) color scales. The optical simulations from RCWA are performed with the following stacking and geometrical dimensions: glass substrate (thickness = 1 mm), FTO thin films (thickness = 300 nm), ZnO seed layer (thickness = 20 nm), ZnO NWs (length = 1 μm, diameter = 75 nm, period = 345 nm, correlated spacing = 150 nm), CdTe shell (thickness = 60 nm), and CuSCN layer (thickness = 1 μm). The Au back-side contact is taken as semi-infinite.