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

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. (C) 2017 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.