Size-modulation of functionalized FeO: nanoscopic customization to devise resolute piezoelectric nanocomposites.

Magnetite (FeO), a representative relaxor multiferroic material, possesses fundamentally appealing multifaceted size-dependent properties. Herein, to evaluate a prototype spinel transition metal oxide (STMO), monodispersed and highly water-dispersible spherical magnetite nanoparticles (MNPs) with an enormous size range (3.7-242.

Negative capacitance switching in size-modulated FeO nanoparticles with spontaneous non-stoichiometry: confronting its generalized origin in non-ferroelectric materials.

Persistent low-frequency negative capacitance (NC) dispersion has been detected in half-metallic polycrystalline magnetite (Fe3O4) nanoparticles with varying sizes from 13 to 236 nm under the application of moderate dc bias. Using the Havriliak-Negami model, 3D Cole-Cole plots were employed to recapitulate the relaxation times (τ) of the associated oscillating dipoles, related shape parameters (α, β) and resistivity for the nanoparticles with different sizes. The universal Debye relaxation (UDR) theory requires a modification to address the shifted quasi-static NC-dispersion plane in materials showing both +ve and -ve capacitances about a transition/switching frequency (f0).

Resonant energy transfer in a van der Waals stacked MoS - functionalized graphene quantum dot composite with ab initio validation.

Graphene-based van der Waals (vdW) heterostructures can facilitate exciting charge transfer dynamics in between structural layers with the emission of excitonic quasi-particles. However, the chemical formation of such heterostructures has been elusive thus far. In this work, a simple chemical approach is described to form such van der Waals (vdW) heterostructures using few layer MoS2 sheet embedded quantum dots (QDs) and amine-functionalized graphene quantum dots (GQDs) to probe the energy transfer mechanism for tunable photoluminescence (PL).

Exploring the effect of hole localization on the charge-phonon dynamics of hole doped delafossite.

For weak or moderate doping, electrical measurement is not suitable for detecting changes in the charge localization inside a semiconductor. Here, to investigate the nature of charge-phonon coupling in the presence of gradually delocalized holes within a weak doping regime (~10 cm), we examine the temperature dependent Raman spectra (303-817 K) of prototype hole doped delafossite [Formula: see text] (x  =  0/0.03, y  =  0/0.

Local Field Enhancement-Induced Enriched Cathodoluminescence Behavior from CuI-RGO Nanophosphor Composite for Field-Emission Display Applications.

Field-emission displays (FEDs) constitute one of the major foci of the cutting edge materials research because of the increasingly escalating demand for high-resolution display panels. However, poor efficiencies of the concurrent low voltage cathodoluminescence (CL) phosphors have created a serious bottleneck in the commercialization of such devices. Herein we report a novel CuI-RGO composite nanophosphor that exhibits bright red emission under low voltage electron beam excitation.

Colossal magnetoresistance in amino-functionalized graphene quantum dots at room temperature: manifestation of weak anti-localization and doorway to spintronics.

In this work, we have demonstrated the signatures of localized surface distortions and disorders in functionalized graphene quantum dots (fGQD) and consequences in magneto-transport under weak field regime (∼1 Tesla) at room temperature. Observed positive colossal magnetoresistance (MR) and its suppression is primarily explained by weak anti-localization phenomenon where competitive valley (inter and intra) dependent scattering takes place at room temperature under low magnetic field; analogous to low mobility disordered graphene samples. Furthermore, using ab-initio analysis we show that sub-lattice sensitive spin-polarized ground state exists in the GQD as a result of pz orbital asymmetry in GQD carbon atoms with amino functional groups.

Efficient and persistent cold cathode emission from CuPc nanotubes: a joint experimental and simulation investigation.

In the current report, chemically synthesized copper phthalocyanine (CuPc) nanotubes are shown to exhibit unprecedentedly well cold cathode emission characteristics with turn-on field (3.2 V μ m(-1)) and stable emission during long intervals (200 min). Simulation of electric field distribution via finite element method around an isolated nanotube emitter in a manner parallel to the experimental setup (inter-electrode distance = 180 μm) exhibits good corroboration of theoretical premises with experimental findings.

Amino-functionalized graphene quantum dots: origin of tunable heterogeneous photoluminescence.

Graphene quantum dots are known to exhibit tunable photoluminescence (PL) through manipulation of edge functionality under various synthesis conditions. Here, we report observation of excitation dependent anomalous m-n type fingerprint PL transition in synthesized amino functionalized graphene quantum dots (5-7 nm). The effect of band-to-band π*-π and interstate to band n-π induced transitions led to effective multicolor emission under changeable excitation wavelength in the functionalized system.

Charge compensation assisted enhanced photoluminescence derived from Li-codoped MgAl2O4:Eu3+ nanophosphors for solid state lighting applications.

Highly-luminescent nanophosphors have a decisive role in solid-state lighting (SSL) as well as in field emission display (FED) applications due to their potential use in fabrication of nanophosphor based FED and solid state display devices. Herein, the red emitting highly-luminescent Eu(3+)-Li(+) co-doped magnesium aluminate (MgAl2O4) nanophosphors were synthesized by a customized sol-gel route with an average particle size of 18 nm, which can be easily scaled up in a large quantity. The resulting nanophosphor exhibits hypersensitive red emission, peaking at 615 nm upon 394 nm excitation.