SrTiO3 Nanocrystals Research Articles

Preparation and Band Energetics of Transparent Nanostructured SrTiO3 Film Electrodes

Transparent nanostructured SrTiO3 film electrodes were fabricated on conductive substrates from SrTiO3 nanocrystals. Band energetics were determined with spectroelectrochemical measurements, and its trap states were investigated with electrochemistry. The flat band edges (Efb) of nanostructured SrTiO3 electrodes were highly dependent on the pH of the electrolyte, and measured to be −0.71, −0.96, and −1.19 V versus saturated Ag/gCl at pH 3.0, 6.8, and 13.0, respectively. The time-resolved current at different applied potentials positive of the flat band edge clearly indicate a trap-filling process. The results showed that trap state densities are also highly pH dependent. Total trap state densities of 2.0 × 1015, 8.08 × 1015, and 1.21 × 1016 cm−2 were determined at pH 3.0, 6.8, and 13.0, respectively with maximum located at −0.25, −0.50, and −0.70 V. The results obtained from cyclic voltammograms are in good agreement with that obtained from the measurements of time-resolved currents. The size of the peak ...

Open-Bench Method for the Preparation of BaTiO3, SrTiO3, and BaxSr1-xTiO3 Nanocrystals at 80 °C

In this letter, we report the first facile open-bench synthesis of BaTiO3, SrTiO3 nanocrystals, and their nanosolid solutions BaxSr1-xTiO3 (BST) at 80 degrees C. The size of the BST nanoparticles was readily tuned from approximately 50 to approximately 10 nm with achievable giant dielectric constants. The process yielded these important perovskite mixed-metal oxide crystals of high quality on the nanometer scale without a history of thermal stress. This new synthesis system involves inorganic starting materials without organic components and does not require demanding conditions such as an inert environment, high pressure, and high temperature.

Erasable photomemory phenomena in Eu2O3‐, Y2O3‐ and SrTiO3 nanoparticles at room temperature

AbstractReversible ultraviolet‐laser‐light‐induced spectral changes have been observed for Eu2O3‐, Y2O3‐ and SrTiO3 nanocrystal specimens at room temperature. Comparing with their bulk specimens, the speed of the changes in the nanoparticle specimens tend to increase. The transitions are explained by photo‐induced reduction and photo‐induced oxidation at nanocrystal surfaces due to exciton instability. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Formation of SrTiO3 nanocrystals in amorphous Lu2O3 high-k gate dielectric for floating gate memory application

We have developed a method based upon pulsed laser deposition to produce SrTiO3 nanocrystals embedded in amorphous Lu2O3 high-k dielectric. The high resolution transmission electron microscopy study revealed the complete isolation of SrTiO3 nanocrystals embedded in Lu2O3 matrix with 4nm diameter and well distributed with an area density estimated to be about 8×1011cm−2. A pronounced capacitance-voltage hysteresis is observed with a memory window of ∼1.5V under the 6V programming. In addition, the retention characteristics are tested to be robust.

04/02140 INSEDELF: method of studying separation in liquid-liquid phase application to water-diesel fuel emulsions: Schulz, P. et al. Fuel, 2004, 83 (1), 137–142

A sol–gel method with the aid of structure-directing surfactant was successfully used to synthesize mesoporous-assembled SrTiO3 nanocrystal photocatalysts by using strontium nitrate (Sr(NO3)2) and tetraisopropyl orthotitanate (TIPT) as precursors. Anhydrous ethanol (EtOH), ethylene glycol (EG), or EtOH/EG was selected as a solvent, while laurylamine hydrochloride (LAHC), cetyltrimethylammonium bromide (CTAB), or cetyltrimethylammonium chloride (CTAC) was used as a structure-directing surfactant. The photodegradation of methyl orange by SrTiO3 was found to be affected by the crystallinity, specific surface area, and pore characteristic. The mesoporous-assembled structure with a high pore uniformity of SrTiO3 plays the most important role affecting the photocatalytic activity of the SrTiO3 photocatalyst. The SrTiO3 with the mesoporous-assembled structure and narrow pore size distribution synthesized at a calcination temperature of 700 °C, a heating rate of 1 °C min−1, a LAHC-to-TIPT molar ratio of 0.25:1, and using an EtOH solvent provided the highest photocatalytic degradation activity, which was much higher than that of the non-mesoporous-structured commercial SrTiO3.

MICROSTRUCTURES AND OPTICAL PROPERTIES OF STRONTIUM TITANATE NANOCRYSTALS PREPARED BY A STEARIC-ACID GEL PROCESS

SrTiO3 nanocrystals with grain sizes from 26 to 86 nm were prepared by stearic-acid gel method. The microstructures, lattice vibration and luminescence spectra were examined by X-ray diffraction, infrared, Raman and photoluminescence (PL) spectroscopies. Hydroxyl defects were clearly found by infrared spectroscopy in the SrTiO3 nanocrystals. Raman measurement results showed that internal stress exists in the SrTiO3 nanocrystals, which induces first-order Raman scattering processes. Strong visible PL near 2.62 eV was observed under 3.54 eV light excitation in small SrTiO3 nanocrystals. Grain-size dependence of the PL spectrum is investigated and the origin for the PL is attributed to a charge transfer via intrinsic defects inside an oxygen octahedron.