Observation of negative terahertz photoconductivity in strongly correlated electron-doped CaMnOthin film.

Electron-doped CaCeMnO(CCMO) possesses a unique band structure and exhibits a giant topological Hall effect contrary to other correlation-driven manganites known for insulator-to-metal transition, magnetoresistance, complex magnetic order, etc. The interaction mechanisms among the fundamental entities and their dynamical evolutions responsible for this unusual topological phase are yet to be understood. Here, we employ time-averaged and sub-picosecond time-resolved terahertz (THz) spectroscopy to explore the low-energy steady-state and ultrafast carrier dynamics, respectively, to unravel the complexity of charge carriers during their transition from a non-equilibrium state to the ground state in CCMO thin film.

Dual co-catalysts activated hematite nanorods with low turn-on potential and enhanced charge collection for efficient solar water oxidation.

Hematite (-FeO) photoanode suffers from significant photocarrier recombination and sluggish water oxidation kinetics for photoelectrochemical water splitting. To address these challenges, this work demonstrates the construction of dual co-catalysts modified FeOnanorods photoanode by strategically incorporating CoPi and Co(OH)for photoelectrochemical water oxidation. The FeO/CoPi/Co(OH)nanorods photoanode exhibits the lowest ever turn-on potential of 0.

Catalytic Hydrogen Doping of NdNiO Thin Films under Electric Fields.

The electric-field-assisted hydrogenation and corresponding resistance modulation of NdNiO (NNO) thin-film resistors were systematically studied as a function of temperature and dc electric bias. Catalytic Pt electrodes serve as triple-phase boundaries for hydrogen incorporation into a perovskite lattice. A kinetic model describing the relationship between resistance modulation and proton diffusion was proposed by considering the effect of the electric field during hydrogenation.

Three-Dimensional Nanoconfinement Supports Verwey Transition in FeO Nanowire at 10 nm Length Scale.

Herein, we construct three-dimensional (3D) FeO epitaxial nanowires at a 10 nm length scale on a 3D MgO nanotemplate using an original nanofabrication technique that mainly comprises nanoimprint lithography and inclined thin-film deposition. Despite the high density of inevitable nanoscale defects, the ultrasmall FeO nanowires exhibit a prominent Verwey transition at about 112 K with a maximum relative change in resistance of 9.5, which is 6 times larger than that of the thin-film configuration.

Surface Electronic States Induced High Terahertz Conductivity of CoO Microhollow Structure.

Herein, we report the observation of unusual electronic and magnetic phases in traditional antiferromagnetic CoO micromaterials and modulation of their properties on a temperature scale. In particular, we demonstrate a comparative low-energy carrier dynamics of CoO microflower and microhollow flower (MHF) structures of same average size of 2 μm to unravel the ground-state information induced by surface electronics across the insulator-semiconductor transition using terahertz (THz) time domain spectroscopy. Interestingly, the THz optical constants of these structures are found to exhibit remarkably distinct features both as a function of frequency and temperature.

Ligand-induced evolution of intrinsic fluorescence and catalytic activity from cobalt ferrite nanoparticles.

To develop CoFe(2)O(4) as magneto-fluorescent nanoparticles (NPs) for biomedical applications, it would be advantageous to identify any intrinsic fluorescence of this important magnetic material by simply adjusting the surface chemistry of the NPs themselves. Herein, we demonstrate that intrinsic multicolor fluorescence, covering the whole visible region, can be induced by facile functionalization of CoFe(2)O(4) NPs with Na-tartrate. Moreover, the functionalized CoFe(2)O(4) NPs also show unprecedented catalytic efficiency in the degradation of both biologically and environmentally harmful dyes, pioneering the potential application of these NPs in therapeutics and wastewater treatment.

Surface modification of MnFe₂O₄ nanoparticles to impart intrinsic multiple fluorescence and novel photocatalytic properties.

The MnFe2O4 nanoparticle has been among the most frequently chosen systems due to its diverse applications in the fields ranging from medical diagnostics to magnetic hyperthermia and site-specific drug delivery. Although numerous efforts have been directed in the synthesis of monodisperse MnFe2O4 nanocrystals, unfortunately, however, studies regarding the tuning of surface property of the synthesized nanocrystals through functionalization are sparse in the existing literature. Herein, we demonstrate the emergence of intrinsic multicolor fluorescence in MnFe2O4 nanoparticles from blue, cyan, and green to red, upon functionalization and further surface modification with a small organic ligand, Na-tartrate.