BaTiO3 Nanocubes Research Articles

Nano-sized cube-shaped single crystalline oxides and their potentials; composition, assembly and functions

Nanocrystals, especially with an anisotropic shape such as cubic, are candidates as building blocks for new bottom-up approaches to materials assembly, yielding a functional architecture. Such materials also receive attention because of their intrinsic size-dependent properties and resulting applications. Here, we report synthesis and characteristics of CeO2, BaTiO3 and SrTiO3 nanocubes and the ordered assemblies. The importance of shape as well as size distribution is clarified for the bottom-up development of 3D fine structures. CeO2 nanocube assemblies with enhanced surface of specified crystal planes such as (100) and (111) would open new surface-dominant devices. BaTiO3 and SrTiO3 nanocubes with narrow size distributions and robust diversity in compositions were obtained. BaTiO3 films made up of ordered nanocube assemblies were fabricated on various substrates by evaporation-induced self-assembly method. Regardless of the substrate, the nanocubes exhibited {100} orientations and a high degree of face-to-face ordering, which remained even after heat treatment at 850°C. The supracrystal films exhibited distinct ferroelectric behaviors.

Growth and self-assembly of BaTiO3 nanocubes for resistive switching memory cells

In this work, the self-assembled BaTiO3 nanocubes based resistive switching memory capacitors are fabricated with hydrothermal and drop-coating approaches. The device exhibits excellent bipolar resistance switching characteristics with ON/OFF ratio of 58–70, better reliability and stability over various polycrystalline BaTiO3 nanostructures. It is believed that the inter cube junctions is responsible for such a switching behaviour and it can be described by the filament model. The effect of film thickness on switching ratio (ON/OFF) was also investigated in details.

BaTiO3 nanocube and assembly to ferroelectric supracrystals

Abstract

Characteristics of Barium Titanate Nanocube Ordered Assembly Thin Films Fabricated by Dip-Coating Method

Ordered assembly thin films of BaTiO3 (BT) nanocubes were fabricated on various Pt-coated substrates by dip-coating self-assembly and sintered at 850 °C. BT nanocubes aligned face-to-face in a wide region about 20 µm2 with a height of about 600 nm. The thickness of the assembly film was able to be controlled by changing the density of the BT nanocube dispersed solution. The local microstructure of the nanocube assembly was observed by high-resolution transmission electron microscopy. It is revealed that the nanocubes were conjugated face-to-face without grain growth. The piezoresponse properties of BT nanocube assembled films on various substrates were investigated by scanning probe microscopy with a relatively high-force-constant cantilever. The relations between piezoelectric constant and electrical field showed ferroelectric hysteresis loops with high rectangularity.

Solvothermal growth of sub-10 nm monodispersed BaTiO3 nanocubes

Sub-10 nm BaTiO3 nanocubes that can be highly dispersible in nonpolar solvents were successfully synthesized by using a solvothermal method with oleic acid as the surfactant. The results showed that BaTiO3 nanoparticles were capped with oleic acid molecules, which was essential for size control and monodispersibility of BaTiO3 nanocubes.

Optical and ferroelectric properties of ruthenium-doped BaTiO3 nanocubes

Structural, optical, dielectric and ferroelectric properties of Ru-doped BaTi1−xRuxO3(x = 0.01, 0.03, 0.05, 0.07, 0.10) nanocubes have been investigated. The average size of nanocube obtained from Rietveld refinement is in the range 35–60 nm. The incorporation of Ru leads to a mixed tetragonal and cubic crystalline phases in doping concentration range 5–7%. Optical band gap changes from 3.2 to 2.74 eV with increase in Ru concentration. Replacement of Ti with Ru quenches band-edge emission and enhances defect emission intensity. Optical absorption and emission spectra have been interpreted in terms of oxygen vacancy. Ruthenium 4d orbital plays a crucial role to improve dielectric constant and diminish ferroelectric Curie temperature. The combined effect of Ru dopant and size gives rise to complex variation of Curie temperature.

Piezoresponse properties of orderly assemblies of BaTiO3 and SrTiO3 nanocube single crystals

Orderly assemblies of BaTiO3 (BT) nanocubes, SrTiO3 (ST) nanocubes and BT-ST mixture nanocubes were fabricated on Pt-coated Si substrate directly by solution self-assembly and heated at 850 °C. The dielectric nanocubes aligned face to face in a quite wide region of several tens of square-micrometers with a height of one micrometer, and even inside of the structures was ordered. The piezoresponse of BT-ST mixture assembly showed non-linear curve and stepwise behavior at high poling field, which differed from ferroelectric BT and paraelectric ST nanocube assemblies.

In situ growth BaTiO3 nanocubes and their superlattice from an aqueous process

Ordered aggregated BaTiO(3) nanocubes with a narrow size distribution were obtained in an aqueous process by using bis(ammonium lactate) titanium dihydroxide (TALH) as Ti source in the presence of oleic acid and tert-butylamine. Kinetics of the formation of BaTiO(3) nanocubes indicated that an in situ growth mechanism was dominant and the superlattice of nanocubes formed in situ through the growth of BaTiO(3) nanoparticles in Ti-based hydrous gel. The size and morphology of nanocubes were controlled by tuning the concentration and molar ratio of surfactants. A novel growth model dependant on the structure of Ti precursor for the formation and morphology control of BaTiO(3) nanocubes and their superlattice was demonstrated.

Preparation of barium titanate nanocube particles by solvothermal method and their characterization

Barium titanate (BaTiO3) nanocube particles below 20 nm were prepared by solvothermal method. A selection of organic solvent and inorganic materials of Ba and Ti sources was most important for the preparation of nanocubes. A nucleation and particle growth of BaTiO3 nanoparticles led to a formation of the BaTiO3 nanocubes with a size of 10–15 nm at temperatures above 200 °C.

Solvothermal Preparation and Characterization of Barium Titanate Nanocubes

Abstract A simple low-temperature solvothermal scheme has been developed to produce pure, well-controlled characteristics in terms of size, morphology, and monodispersity of barium titanate (BaTiO3) nanocubes. Characterizations of products were performed by XRD, TEM, HRTEM, EDS, and their sizes were 40–50 nm. The formation process of the BaTiO3 nanocubes was also discussed.

Solvothermal Synthesis of Single-crystalline BaTiO3 Nanocubes in a Mixed Solution

Abstract The preparation of single-crystalline cubic perovskite BaTiO3 nanocubes with edge length of 40–90 nm via a solvothermal method without surfactant was reported, and the formation mechanism of the BaTiO3 nanocubes was discussed.