Novel photoswitchable dielectric properties on nanomaterials of electronic core–shell γ-FeOx@Au@fullerosomes for GHz frequency applications

Abstract

We unexpectedly observed a large amplification of the dielectric properties associated with the photoswitching effect and the new unusual phenomenon of delayed photoinduced capacitor-like (i.e. electric polarization) behavior at the interface on samples of three-layered core–shell (γ-FeO_x@AuNP)@[C₆₀(>DPAF-C₉)]_n2 nanoparticles (NPs) in frequencies of 0.5–4.0 GHz. The detected relative dielectric constant amplification was initiated upon switching off the light followed by relaxation to give an excellent recyclability. These NPs having e⁻-polarizable fullerosomic structures located at the outer layer were fabricated from highly magnetic core–shell γ-FeOx@AuNPs. Surface-stabilized 2 in a core–shell structure was found to be capable of photoinducing the surface plasmonic resonance (SPR) effect by white LED light. The accumulated SPR energy was subsequently transferred to the partially bilayered C₆₀(>DPAF-C₉) fullerosomic membrane layer in a near-field (∼1.5 nm) region without producing radiation heat. Since the monostatic SAR signal is dielectric property-dependent, we used these measurements to provide evidence of derived reflectivity changes on a surface coated with 2 at 0.5–4.0 GHz upon illumination of LED white light. We found that a high, >99%, efficiency of response amplification in image amplitude can be achieved.