Chiral Magnetic Oxide Nanomaterials: Magnetism Meets Chirality

Abstract

Chiral magnetic oxide nanomaterials (CMONs), which combine the beneficial effects of chirality and magnetism in a single unit, have found applications in biomedical, optical, and electronic devices as well as in catalysis and sensing. This is largely due to the simultaneous presence of magnetic properties, catalytic activity, biocompatibility and optical activity, or magneto‐optical effects, which are circular polarization and magnetization dependent. This review summarizes the key findings derived from recent research works on the synthesis, properties, and applications of CMONs. The three main approaches in the synthesis and property tuning of CMONs, namely, post‐functionalization, in situ approach, and assembly with soft templates, are discussed. A summary and some future prospects of the CMONs with respect to their synthetic routes, chirality origin, and applications are also provided.

Chiral Induced Spin Selectivity

“…A wide array of chiral magnetic oxides are becoming available and offer promise for a range of applications. 189 Interest in chiral metal oxides for CISSapplications stems from initial research showing that electrodes coated with chiral molecules reduces the reaction overpotential for the oxygen evolution reaction compared to analogous electrodes coated with achiral molecules (see Section 6.3.1). 41 By adapting the electrodeposition methods developed by Switzer and co-workers, 190,191 chiral CuO coated electrodes were studied by Mott polarimetry and shown to exhibit spin polarizations of ∼10%.…”

“…A wide array of chiral magnetic oxides are becoming available and offer promise for a range of applications . Interest in chiral metal oxides for CISS-applications stems from initial research showing that electrodes coated with chiral molecules reduces the reaction overpotential for the oxygen evolution reaction compared to analogous electrodes coated with achiral molecules (see Section ).…”

Electron-Withdrawing meso-Substituents Turn On Magneto-Optical Activity in Porphyrins

“…MORD and magnetic circular dichroism (MCD) are paired responses referred together as magneto-optical activity (MOA). − Current MOA components are typically fabricated from paramagnetic glasses and modulate polarization within changing magnetic fields. − The creation of molecular materials that exhibit MOA will open new applications and allow for the development of new technologies. Indeed, recent MOA reports highlight magnetic nanoparticles, − polymer thin films, − and other materials that show promise in this research space. − …”

High-Throughput Morphological Chirality Quantification of Twisted and Wrinkled Gold Nanorods

“…Nanostructures can present chiral features at multiple scales, from atomic up to submicron scale. The identification and implementation of chirality in inorganic nanoparticles (NPs) have given rise to a new class of materials having the intriguing property of not being superimposable to their mirror images, with promising applications. − Metallic chiral NPs particularly have received growing interest because of their unique chiroptical properties. Structural features resulting from different synthetic approaches have been found to show a significant variation, but in general, the scales of the chiral features are in the nanometer range. − The surface plasmon resonance of metal chiral NPs, which corresponds to the collective oscillations of electrons driven by light, results in strong near-field enhancement, optical absorption maxima at the resonance wavelength, and, in turn, unusually high optical activity .…”

“…A broad range of synthesis procedures have been proposed to transfer chirality to inorganic NPs. − ,− Among these, colloidal synthesis is arguably the most promising route because of its scalability and low cost. However, the unavoidable polydispersity in colloidal systems also increases the variability of the often complex morphology of chiral NPs.…”