RESULTS AND DISCUSSION The synthesis of Au@ZnO core@shell NPs has been adapted and modified from the method described by Zeto et al., and proceeds via a three-step process: i) first the Au cores are synthesized with established colloidal procedures, ii) then a shell of Zn(OH)2 is nucleated around the cores via a hydrothermal treatment, and iii) finally the Au@ZnO NPs are obtained by calcination of the Au@Zn(OH)2 NPs at 500 °C in air. For the synthesis of Au@AZO NPs, an additional step of infusing the Au@Zn(OH)2 NPs in a pH-neutral Al 3+ solution is added before calcination. All synthetic details are given in the Experimental Section.