Abstract
Heteronanoparticles represent a new class of nanomaterials exhibiting multifunctional and collective properties, which could find applications in medical imaging and therapy, catalysis, photovoltaics, and electronics. This present work demonstrates the intrinsic heteroepitaxial linkage in heterodimer nanoparticles to enable interaction of the individual components across their interface. It revealed distinct differences between Au@MnO and Au@Fe3O4 regarding the synthetic procedure and growth kinetics, as well as the properties to be altered by the variation of the electronic structure of the metal oxides. The chemically related metal oxides differ concerning their band gap; while MnO is a Mott-Hubbard insulator with a large band gap, Fe3O4 is a semimetal with thermally activated conductivity. The fluorescence dynamics indicate a prolonged relaxation time (>2 ns) for electrons of the conduction band of the Au nanopartides after interfacing to Fe3O4. Here, the semiconductor is not depleted and forms an ohmic contact to the Au domain. In contrast, the fluorescence dynamics and ESCA of Au@MnO affirmed the weak interaction with the electrons of the Au domain, where the junction behaves as a Schottky barrier.