ZnO cages with tunable shell thickness and photoluminescence properties

Uniform ZnO cages were fabricated via using colloidal carbon spheres as sacrificing template. ZnO precursor could be easily coated on the carbon spheres by soaking the template into Zn(CH3COO)2 aqueous solution. After calcination, the average diameter of the cages was 200 nm which experienced a large shrinkage from the initial carbon template (600 nm). The shell thickness of the cages could be manipulated from 20 nm to 40 nm by adjusting the concentration of Zn(CH3COO)2. The correlation between the shell thickness and photoluminescence (PL) performances of these cages was also investigated. Moreover, this facile method could be potentially adopted as a general way to fabricate hollow structures of other metal oxides.