Aligned CdSe@ZnO flower-rod core–shell nanocable as photovoltaic application

The large bandgap of ZnO limits its application in photovoltaic devices , thus the semiconductor quantum dots (QDs), such as CdSe, is utilized to improve light-harvesting efficiency of solar cells. The CdSe@ZnO flower-rod core–shell nanocable arrays (CSZFRs) are prepared with a simple ion exchange method from aqueous solutions. The optical absorptions of the nanocable arrays can be controllably tuned to cover almost the entire visible spectrum (>750 nm) via quantum dots (QDs) sensitized attributed to the smaller band gap of CdSe. Moreover, a typical type II band alignment enhance the separation of photogenerated charge carriers, and reduce the electron–hole recombination within CSZFRs, demonstrated by the photoluminescence (PL) quenching after the formation of CSZFR hybrid structures. In addition, the CdSe-sensitized ZnO nanostructures demonstrate broad external quantum efficiency (EQE) in the spectrum from 300 to 740 nm. Therefore, the CSZFRs nanocable heterostruture exhibits a photovoltaic performance with a higher open-circuit photovoltage (−0.93 V Ag/AgCl ) and short-circuit photocurrent (1.00 mA cm −2 ).