Anatase nanoparticles were obtained through a modified sol–gel route from titanium isopropoxide with acetic acid in order to control hydrolysis and condensation reactions. The modification of Ti(OiPr)4 reduces the availability groups that hydrolyze condense easily formation stable complex whose structure was determined be Ti(OCOCH3)(OiPr)2 by means FTIR 13C NMR. presence this confirmed early stages process. A doublet 1542 1440 cm−1 stands for asymmetric symmetric stretching vibrations...

This paper proposes a polaronic stacking fault defect model as the origin of huge dielectric properties in CaCu3Ti4O12 (CCTO) materials. The reconciles opposing views researchers on both sides intrinsic versus extrinsic debate about unusually high values constant measured for CCTO its various forms. Therefore, by considering phenomena, it was shown that internal barrier layer capacitance mechanism is enhanced another similar, but different nature, operates nanoscale range due to polaron...

We report here the utilization of atomic layer deposition to passivate surface trap states in mesoporous TiO2 nanoparticles for solid-state dye-sensitized solar cells based on 2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenylamine)-9,9′-spirobifluorene (spiro-OMeTAD). By depositing ZrO2 films with angstrom-level precision, coating produces over a two-fold enhancement short-circuit current density, as compared control device. Impedance spectroscopy measurements provide evidence that reduces...

The detection of specific biomarkers for health monitoring, i.e., molecular diagnostics, can be classified as early or emergency diagnostics. Emergency diagnostics is related to those diseases which necessary a rapid patient intervention, such stroke and cardiac attack, in addition the infectious monitor control outbreaks epidemics, diagnosis requires highly sensitive quantification to, specially, degenerative cancer successful treatment. Herein, challenges designing improved point-of-care...

A model is proposed here to explain how the chemical features of metal oxide varistors can alter their nonohmic physical behavior, based on similarities in electrical properties ZnO- and SnO2-based varistors. The explains before after thermal treatments oxygen- nitrogen-rich atmospheres, which cause similar changes feature these polycrystalline ceramics with greatly differing compositions microstructures. key role that oxygen plays varistor grain boundaries, independently type ceramic system...

The electrical properties of tin oxide varistors doped with CoO, Nb2O5, and Cr2O3, were investigated using the impedance spectroscopy technique temperature ranging from 25 to 400 °C. data, represented by means Nyquist diagrams, show two time constants different activation energies, one at low frequencies other high frequencies. These energies associated adsorption reaction O2 species grain boundary interface. Arrhenius plots slopes a turnover 200 °C for both higher lower frequency constants....

Anatase TiO2 colloidal dispersions were obtained by hydrothermal synthesis at 200 °C from titanium isopropoxide gels modified with acetic acid in the presence of a non-ionic surfactant. Absolute ethanol, anhydrous terpineol and ethyl cellulose added to this anatase dispersion resulting 23 wt% paste. Mesoporous films for application as working electrodes dye-sensitized solar cells prepared screen-printing method, yielding reproducible thicknesses about 10 μm desired porosity levels single...

Redox active self-assembled monolayers inherently possess both electrochemically addressable and polarizable components. The latter will contribute, with additional parasitic terms, to the iR drop effects within any form of electronic analysis, potentially distorting results. A capacitive analysis such interfaces (Electroactive Monolayer Capacitance Spectroscopy), presented here, enables a clean mapping thermodynamic kinetic faradaic characteristics in single experimental run, nonfaradaic...

The presence of self-assembled monolayers at an electrode introduces capacitance and resistance contributions that can profoundly affect subsequently observed electronic characteristics. Despite the impact this on any voltammetry, these are not directly resolvable with clarity by standard electrochemical means. A capacitive analysis such interfaces (by spectroscopy), introduced here, enables a clean mapping features additionally presents means studying layer polarizability Cole-Cole...

The introduction of a dense TiO2 layer between the mesoporous network and charge collector in dye-sensitized solar cell anodes has been claimed to improve performance devices. Two mechanisms have proposed explain this behavior, decrease electron–hole recombination at substrate/electrolyte interface an enhancement electronic contact collecting electrode. In work effect sputtered blocking layers (BLs) on cells electrodes analyzed. It shown that electron injection efficiency governed changes...

An electrode surface confined redox group contributes to a substantial potential-dependent interfacial charging that can be sensitively probed and frequency-resolved by impedance-derived capacitance spectroscopy. In utilizing the sensitivity of this fingerprint environment, one seek generate derived sensory configurations. Exemplified here through generation mixed molecular films comprising ferrocene antibody receptors two clinically important targets, label-free methodology is able report...

Label-free approaches for molecular diagnostic applications are appealing because of their inherent point-of-care advantages. Nonetheless, technical challenges impose a limit on the use these methods as will be discussed in this paper. Electrochemical spectroscopic methods, such impedance and impedance-derived highly effective development label-free assays, but they require careful control dynamics sensing interface. We herein report strength current methodologies associated with by focusing...

Electrochemical immunosensors offer much in the potential translation of a lab based sensing capability to useful "real world" platform. In previous work we have introduced an impedance-derived electrochemical capacitance spectroscopic analysis as supportive reagentless means reporting on analyte target capture at suitably prepared mixed-component redox-active, antibody-modified interfaces. Herein directly integrate receptive aptamers into redox charging peptide support enabling label-free...