Synthesis of ZnCdSe@ZnO Hollow Spheres in Different Sizes for Quantum Dots Sensitized Solar Cells Application.

ZnCdSe@ZnO hollow spheres (HS) were successfully fabricated for application in quantum dot sensitized solar cells (QDSSCs) based on ZnO HS through the ion-exchange process. The sizes of the ZnCdSe@ZnO HS could be tuned from ~300 nm to ~800 nm using ZnO HS pre-synthesized by different sizes of carbonaceous spheres as templates. The photovoltaic performance of QDSSCs, especially the short-circuit current density (J), experienced an obvious change when different sizes of ZnCdSe@ZnO HS are employed. The ZnCdSe@ZnO HS with an average size distribution of ~500 nm presented a better performance than the QDSSCs based on other sizes of ZnCdSe@ZnO HS. When using the mixture of ZnCdSe@ZnO HS with different sizes, the power conversion efficiency can be further improved. The size effect of the hollow spheres, light scattering, and composition gradient structure ZnCdSe@ZnO HS are responsible for the enhancement of the photovoltaic performance.