Enhanced visible photoelectrochemical properties of ZnO/CdS core/shell nanorods and their correlation with improved optical properties

ZnO/CdS core/shellnanorods (NRs) constructed ofZnO NR cores andCdS coating shells were fabricated by hydrothermally growingZnO NRs and pulsed laser depositingCdS coatings on the grownZnO NRs. The fabricated ZnO/CdS NRs were characterized by field-emission scanning electron microscopy,transmission electron microscopy, selected-area electron diffraction,X-ray diffraction, and Raman backsattering spectroscopy. The optical and photoelectrochemicalproperties were evaluated and their correlation was studied. TheZnO cores andCdS shells are both in a hexagonal wurtzite structure withc-axis orientation. Compared with the bareZnO NRs, the heterostructured ZnO/CdS NRs exhibit improvedoptical properties including strongvisible lightabsorption and quenchedphotoluminescence. The former facilitates the generation of electron-hole pairs by visible optical excitation, and the latter reveals the suppressed radiative recombination of photogenerated charges and hence efficient charge transfer and separation. Correlated with the improvedoptical properties and charge behaviors, the ZnO/CdS NRs show high visible photoelectrochemical activity and excellent photoswitchingproperty, and highvisible light harvesting efficiencies can be expected for the ZnO/CdS NRs.
Source: Applied Physics Letters - Category: Physics Authors: Source Type: research