As a first approach to obtain Au@AZO core@shell NPs, we followed previous experimental procedures for the synthesis of AZO and added a stoichiometric quantity of Al(NO3)3 to the initial hydrothermal reaction mixture containing Zn(NO3)2 (Procedure 1 in Scheme 1). However, such an approach proved to be unsuccessful in leading to well-controlled core@shell nanoparticles, resulting in large quantities of AZO agglomerates decorated with the AuNPs precipitation of Zn(OH)2, which is unstable below pH 6. In fact, the significance of the structural damage to the final AZO shell increases for higher Al 3+ dopant concentration.