Bifunctional CoFe 2 O 4 /ZnO Core/Shell Nanoparticles for Magnetic Fluid Hyperthermia with Controlled Optical Response

LAVORATO, GABRIEL; LIMA, ENIO; VASQUEZ MANSILLA, MARCELO; TROIANI, HORACIO; ZYSLER, ROBERTO; WINKLER, ELIN

JOURNAL OF PHYSICAL CHEMISTRY C

AMER CHEMICAL SOC

Lugar: Washington; Año: 2018 vol. 122 p. 3047 - 3057

1932-7447

Conjugation of optical and magnetic responsesin a unique system at the nanoscale emerges as a powerful toolfor several applications. Here, we fabricated bifunctionalCoFe2O4-core/ZnO-shell nanoparticles with simultaneousphotoluminescence in the visible range and ac magnetic lossessuitable for hyperthermia. The structural characterizationconfirms that the system is formed by a ≈7 nm CoFe2O4core encapsulated in a ≈1.5-nm-thick semiconducting ZnOshell. As expected from its high anisotropy, the magnetic lossesin an ac magnetic field are dominated by the Brown relaxationmechanism. The ac magnetic response of the core/shellsystem can be accurately predicted by the linear responsetheory and differs from that one of bare CoFe2O4 nanoparticlesas a consequence of changes in the viscous relaxation process due to the effect of the magnetostatic interactions.Concerning the optical properties, by comparing core/shell CoFe2O4/ZnO and single-phase ZnO nanoparticles, we found thatthe former exhibits a broader optical absorption and photoluminescence, both shifted to the visible range, indicating that theoptical properties are closely associated with the shell-morphology of ZnO. Being focused on bifunctional nanoparticles with anoptical response in the visible range and a tunable hyperthermia output, our results can help to address current open questionson magnetic fluid hyperthermia.