Description of the interaction phenomenology between phases for multimodal hybrid nanostructures

The description of interaction phenomenology between magnetic and luminescent phases in multimodal hybrid nanostructures (MHNs) based on magnetite nanoparticles (mNPs) assembled into templates of a luminescent conjugated polymer (LCP) with oxime groups (TUTM) is reported. The MHNs were obtained from the combination of mNPs and TUTM, which were previously synthesized in a separated way, following chemical routes. These MHNs were characterized by transmission electron microscopy techniques, infrared spectroscopy, X-ray photoelectron spectroscopy, fluorescence spectroscopy, as well as magnetic and magneto-optical measuring. The experimental evidence shows the formation of nanoparticle assemblies into the LCP. This is related with the fact that mNPs are immobilized in the TUTM by coordination bonds between oxime groups and Fe²⁺ or Fe³⁺ cations at their surface. Moreover, these coordination bonds promote the photoinduced electron transfer from lowest unoccupied molecular orbital of TUTM to the unfilled d orbitals of Fe²⁺ or Fe³⁺ in mNPs that leads to the fluorescence quenching of the LCP. Likewise, they provoke the formation of a new non-fluorescent complex, which gives arise a static quenching of the luminescent phase. In addition, the mNPs assembling induces the exchange coupling among nanoparticles that diminishes the effective anisotropy of the magnetic phase. Moreover, it was observed that the magnetic hardness of the MHNs decreases in the presence of light stimulus. This is related with the photoinduced electrons transfer between phases. Accordingly, the spin of those electrons could contribute to the antiparallel alignment in the magnetic phase, softening the response of MHNs.