Double-layered core–shell structure of NaYF4:Yb,Er@SiO2@Zn1−xMnxO for near-infrared-triggered photodegradation and antibacterial application

[Display omitted] A novel NIR-responsive photocatalyst NaYF4:Yb,Er@SiO2@Zn1−xMnxO with double-layered core–shell structure was prepared by a three-step reaction. NaYF4:Yb,Er serves as a NIR-to-visible upconverter and provides “visible light” or “necessary energy” to Zn1−xMnxO. Meanwhile, Mn2+-doping in Zn1−xMnxO can extend the photoresponse of ZnO to visible-light region and enhance its charge separation. The nanocomposite exhibits good activity for dye decomposition and antibacterial property under NIR irradiation. The “energy absorption – energy conversion – energy transfer – surface reaction” process dominates the overall photocatalytic activity. Based on the standard MTT (abbr. for 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay, NaYF4:Yb,Er@SiO2@Zn1−xMnxO also exhibits good biocompatibility and low cytotoxicity with human umbilical vein endothelial cells (HUVEC) as model cells.