Abstract: A substrate for surface enhanced Raman spectroscopy analysis (SERS) comprises a ferroelectric single crystal having polarization-inverted patterns of spontaneous polarizations including polarization-inverted portions and non-inverted polarization portions, and metallic dots positioned at only either one polarized surfaces of the polarization-inverted portions and the non-inverted polarization portions. The provided SERS substrate produces a high enhancement effect. A microfluidic device incorporating the SERS substrate is also provided.

Abstract: The disclosure provides in one embodiment a method of fabricating a lead zirconate titanate (PZT) nanoparticle ink based piezoelectric sensor. The method has a step of formulating a lead zirconate titanate (PZT) nanoparticle ink. The method further has a step of depositing the PZT nanoparticle ink onto a substrate via an ink deposition process to form a PZT nanoparticle ink based piezoelectric sensor.

Abstract: The present application is directed to electric double layer capacitance (EDLC) devices. In one aspect, the present application is directed to an electrode comprising an activated carbon cryogel having a tunable pore structure wherein: the surface area is at least 1500 m2/g as determined by nitrogen sorption at 77K and BET analysis; and the pore structure comprises a pore volume ranging from about 0.01 cc/g to about 0.25 cc/g for pores having a pore diameter of 0.6 to 1.0 nm. In another aspect, the present application is directed to an Electric Double Layer Capacitor (EDLC) device comprising an activated cryogel.

Abstract: Provided are a novel ZnO dye-sensitized solar cell and method of fabricating the same. In one embodiment, deliberately added lithium ions are used to mediate the growth of ZnO aggregates. The use of lithium provides ZnO aggregates that have advantageous microstructure, morphology, crystallinity, and operational characteristics. Employing lithium during aggregate synthesis results in a polydisperse collection of ZnO aggregates favorable for porosity and light scattering. The resulting nanocrystallites forming the aggregates have improved crystallinity and more favorable facets for dye molecule absorption. The lithium synthesis improves the surface stability of ZnO in acidic dyes. The procedures developed and disclosed herein also help ensure the formation of an aggregate film that has a high homogeneity of thickness, a high packing density, a high specific surface area, and good electrical contact between the film and the fluorine-doped tin oxide electrode and among the aggregate particles.

Abstract: Methods are provided for forming films of orthorhombic V2O5. Additionally provided are the orthorhombic V2O5 films themselves, as well as batteries incorporating the films as cathode materials. The methods use electrodeposition from a precursor solution to form a V2O5 sol gel on a substrate. The V2O5 gel can be annealed to provide an orthorhombic V2O5 film on the substrate. The V2O5 film can be freestanding such that it can be removed from the substrate and integrated without binders or conductive filler into a battery as a cathode element. Due to the improved intercalation properties of the orthorhombic V2O5 films, batteries formed using the V2O5 films have extraordinarily high energy density, power density, and capacity.

Abstract: Electrodes and electric double layer capacitance (EDLC) devices containing an activated carbon cryogel having a tunable pore structure are disclosed. The disclosed electrodes and devices find utility in any number of electrical energy storage and distribution applications.

Abstract: Methods for forming lead zirconate titanate (PZT) nanoparticles are provided. The PZT nanoparticles are formed from a precursor solution, comprising a source of lead, a source of titanium, a source of zirconium, and a mineraliser, that undergoes a hydrothermal process. The size and morphology of the PZT nanoparticles are controlled, in part, by the heating schedule used during the hydrothermal process.

Abstract: The disclosure provides in one embodiment a method of fabricating a lead zirconate titanate (PZT) nanoparticle ink based piezoelectric sensor. The method has a step of formulating a lead zirconate titanate (PZT) nanoparticle ink. The method further has a step of depositing the PZT nanoparticle ink onto a substrate via an ink deposition process to form a PZT nanoparticle ink based piezoelectric sensor.

Abstract: Carbon cryogels, methods for making the carbon cryogels, methods for storing a gas using the carbon cryogels, and devices for storing and delivering a gas using the carbon cryogels.

Abstract: Disclosed are methods and systems for improving actuator performance by reducing tensile stresses in piezoelectric thin films. In one embodiment, a piezoelectric actuator includes a substrate, a first electrode positioned on the substrate, a piezoelectric thin film positioned on the first electrode, and a second electrode positioned on the piezoelectric thin film. The displacement capability of the actuator is enhanced by reducing the tensile stresses of the piezoelectric thin film. In some embodiments, a constant DC voltage applied to the piezoelectric actuator generates compressive in-plane stresses, which counteract the tensile in-plane stresses. As a result, the overall tensile stresses in the actuator are reduced, and the actuator displacement is improved.

Abstract: Methods for forming aggregates of nanomaterials are provided. The aggregates are formed from a liquid dispersion of the nanomaterials in a liquid. The dispersion is aerosolized and the liquid removed from the aerosolized dispersion to provide the aggregates. The aggregates are useful as a photoelectric layer and/or a light-dispersive layer in dye-sensitized solar cells.

Abstract: Aggregate particles comprising titanium dioxide (TiO2) nanotubes, methods for making the aggregate particles, photoelectrodes for solar cells including aggregate particles of nanomaterials, methods for making the photoelectrodes, and solar cells that include the photoelectrodes.

Abstract: Carbon cryogels, methods for making the carbon cryogels, methods for storing a gas using the carbon cryogels, and devices for storing and delivering a gas using the carbon cryogels.

Abstract: The present application is directed to electric double layer capacitance (EDLC) devices. In one aspect, the present application is directed to an electrode comprising an activated carbon cryogel having a tunable pore structure wherein: the surface area is at least 1500 m2/g as determined by nitrogen sorption at 77K and BET analysis; and the pore structure comprises a pore volume ranging from about 0.01 cc/g to about 0.25 cc/g for pores having a pore diameter of 0.6 to 1.0 nm. In another aspect, the present application is directed to an Electric Double Layer Capacitor (EDLC) device comprising an activated cryogel.

Abstract: Provided are a novel ZnO dye-sensitized solar cell and method of fabricating the same. In one embodiment, deliberately added lithium ions are used to mediate the growth of ZnO aggregates. The use of lithium provides ZnO aggregates that have advantageous microstructure, morphology, crystallinity, and operational characteristics. Employing lithium during aggregate synthesis results in a polydisperse collection of ZnO aggregates favorable for porosity and light scattering. The resulting nanocrystallites forming the aggregates have improved crystallinity and more favorable facets for dye molecule absorption. The lithium synthesis improves the surface stability of ZnO in acidic dyes. The procedures developed and disclosed herein also help ensure the formation of an aggregate film that has a high homogeneity of thickness, a high packing density, a high specific surface area, and good electrical contact between the film and the fluorine-doped tin oxide electrode and among the aggregate particles.

Abstract: The invention provides devices, systems, and methods for detecting an analyte vapor. Particularly, electronegative analyte vapors, such as those vapors evolving from explosive compounds, are typical analytes detected the devices. The devices operate using a resistivity change mechanism wherein a nanostructured chemiresistive material undergoes a resistivity change in the presence of an analyte vapor. A resistivity change indicates the presence of an analyte.

Abstract: A carbon-based foam composite including a carbon-based foam and a solid state hydrogen storage material, methods for making the carbon-based foam composite, and methods for using the carbon-based foam composite. Representative carbon-based foams include cryogels, aerogels, and xerogels. Representative solid state hydrogen storage materials include metal hydrides and chemical hydrides.

Abstract: Carbon cryogels, methods for making the carbon cryogels, methods for storing a gas using the carbon cryogels, and devices for storing and delivering a gas using the carbon cryogels.

Abstract: An electric double layer capacitance (EDLC) device is disclosed having an electrode containing an activated carbon cryogel with a tunable pore structure, the carbon cryogel having a surface area of at least 1500 m2/g as determined by nitrogen sorption at 77K and BET analysis, and the pore structure having a pore volume ranging from about 0.01 cc/g to about 0.25 cc/g for pores having a pore diameter of 0.6 to 1.0 nm.

Abstract: A carbon-based foam composite including a carbon-based foam and a solid state hydrogen storage material, methods for making the carbon-based foam composite, and methods for using the carbon-based foam composite. Representative carbon-based foams include cryogels, aerogels, and xerogels. Representative solid state hydrogen storage materials include metal hydrides and chemical hydrides.