Abstract: A metal oxide heterostructure includes mixing a first precursor and a second precursor to form a precursor aqueous mixture, adding at least one constituent to the precursor aqueous mixture to form a first solution, adding a nanostructuring reagent to the first solution to form a second solution, sonochemically treating the second solution to provide a metal oxide powder, filtering, washing, and drying the metal oxide powder to provide a metal oxide nanocomposite heterostructure for a sensing layer of a hydrogen sulfide sensor. A method for forming a hydrogen sulfide sensor includes the metal oxide heterostructure, forming a sensing material, contacting the sensing material with interdigitated electrodes to form a sensing layer, and thermally consolidating the sensing layer to form the hydrogen sulfide sensor.

Abstract: The present disclosure relates to a carbon dioxide sensor able to function in harsh environment, conditions. The carbon dioxide sensor can include a gate-less field effect transistor including a synthetic, quasi-intrinsic, hydrogen-passivated, single-crystal diamond layer exhibiting a 2-dimension hole gas effect, and a sensing layer comprising both a polymer and a hygroscopic material deposited onto a surface of the gate-less field effect transistor.

Abstract: Chemical sensors such as carbon dioxide sensors and methods for making such sensors are disclosed. An example carbon dioxide sensor may include a substrate, with a sensing beam supported by the substrate. The sensing beam may be configured to resonant. A sensing layer may be disposed on the sensing beam, wherein the sensing layer may include an amino group and is configured to sense carbon dioxide. In some instances, a reference beam may also be supported by the substrate, and may be configured to resonant. A reference layer may be disposed on the reference beam, wherein the reference layer may includes an amino group that has been poisoned so that it will be substantially non-sensitive to carbon dioxide.

Abstract: A fluorescence based oxygen sensor can be prepared comprising a polyaniline polymer doped with one or more pyrene carboxylic acids. The polyaniline has the formula: and the pyrene carboxylic acids have the formula: Pyrene-R—COOH??(II); wherein R is an aliphatic linking group having 1 to 11 carbon atoms, n represents half the degree of polymerization, x is about 0.5, and (1?x) is about 0.5. The sensor can be coated onto a support. Upon excitation with an appropriate wavelength, the polyaniline/pyrene coating fluoresces. Upon exposure to oxygen the fluorescence rapidly decays.

Abstract: A fluorescence quenching based oxygen sensor can be prepared comprising a polystyrene polymer linked to pyrene. The fluorescence based sensor has the formula (I), Polystyrene-Y—R-Pyrene??(I); wherein Y is fluorescence quenching and R is an aliphatic linking group having 1 to 11 carbon atoms. The sensor can be coated onto a support and integrated with an LED excitation source and fluorescence detector.

Abstract: A nitrogen dioxide sensor comprising a first beam having a first functionalized sensing surface capable of sensing nitrogen dioxide, the first beam capable of producing a first resonant frequency; and a second beam having a second functionalized reference surface not capable of sensing nitrogen dioxide, the second beam capable of producing a second resonant frequency, wherein differential sensing of nitrogen dioxide may be performed, further wherein the first beam and the second beam are each functionalized with one or more soft bases having comparable viscoelastic properties is provided. In one embodiment, the sensor is a nano-sensor capable of low drift and accurate detection of nitrogen dioxide levels at the zeptogram level. Methods of making and using a nitrogen dioxide sensor are also provided.

Abstract: A fluorescence quenching oxygen sensor (100) comprises a support (102) having coated thereon; a compound having hard or soft acid groups (104); and one or more pyrene compounds (106) represented by Y—R-Pyrene??(I) attached to the compound having hard or soft basic groups; wherein Y is a hard or soft basic group and R is an aliphatic linking group having 1 to 19 carbon atoms. The sensor can be used to prepare a fluorescence quenching oxygen detector.

Abstract: A device comprises a fuel line that carries a combustible fuel including gasoline, a first optical channel that evaluates a degree of absorption at a first wavelength spectrum of light transmitted through the combustible fuel within the fuel line, and a second optical channel that evaluates a degree of absorption at a second wavelength spectrum. The first and second wavelength spectrums consists of wavelengths of between about 800 nanometers (nm) and about 1200 nm. The device further comprises a controller configured to receive inputs from the first and second optical channels representing the degrees of absorption at the first and second wavelength spectrums, correlate the degrees of absorption with proportions of ethanol and water in the combustible fuel, and output data corresponding to the proportions of ethanol and water to a controller of a combustion engine fed with the combustible fuel.

Abstract: A solar cell is disclosed that may include a quantum dot, an electron conductor, and a bifunctional ligand disposed between the quantum dot and the electron conductor. The bifunctional ligand may include a first anchor group that bonds to the quantum dot and a second anchor group that bonds to the electron conductor. The solar cell may include a hole conductor that is configured to reduce the quantum dot once the quantum dot absorbs a photon and ejects an electron through the bifunctional ligand and into the electron conductor. The hole conductor may be a p-type polymer.

Abstract: A fluorescence quenching based oxygen sensor can be prepared comprising a polystyrene polymer linked to pyrene. The fluorescence based sensor has the formula (I), Polystyrene-Y—R-Pyrene??(I); wherein Y is fluorescence quenching and R is an aliphatic linking group having 1 to 11 carbon atoms. The sensor can be coated onto a support and integrated with an LED excitation source and fluorescence detector.

Abstract: Chemical sensors such as carbon dioxide sensors and methods for making such sensors are disclosed. An example carbon dioxide sensor may include a substrate, with a sensing beam supported by the substrate. The sensing beam may be configured to resonant. A sensing layer may be disposed on the sensing beam, wherein the sensing layer may include an amino group and is configured to sense carbon dioxide. In some instances, a reference beam may also be supported by the substrate, and may be configured to resonant. A reference layer may be disposed on the reference beam, wherein the reference layer may includes an amino group that has been poisoned so that it will be substantially non-sensitive to carbon dioxide.

Abstract: A fluorescence based oxygen sensor can be prepared comprising a polyaniline polymer doped with one or more pyrene carboxylic acids. The polyaniline has the formula: and the pyrene carboxylic acids have the formula: Pyrene-R—COOH??(II); wherein R is an aliphatic linking group having 1 to 11 carbon atoms, n represents half the degree of polymerization, x is about 0.5, and (1?x) is about 0.5. The sensor can be coated onto a support. Upon excitation with an appropriate wavelength, the polyaniline/pyrene coating fluoresces. Upon exposure to oxygen the fluorescence rapidly decays.

Abstract: A nitrogen dioxide sensor comprising a first beam having a first functionalized sensing surface capable of sensing nitrogen dioxide, the first beam capable of producing a first resonant frequency; and a second beam having a second functionalized reference surface not capable of sensing nitrogen dioxide, the second beam capable of producing a second resonant frequency, wherein differential sensing of nitrogen dioxide may be performed, further wherein the first beam and the second beam are each functionalized with one or more soft bases having comparable viscoelastic properties is provided. In one embodiment, the sensor is a nano-sensor capable of low drift and accurate detection of nitrogen dioxide levels at the zeptogram level. Methods of making and using a nitrogen dioxide sensor are also provided.

Abstract: A solar cell is disclosed that may include a quantum dot, an electron conductor, and a bifunctional ligand disposed between the quantum dot and the electron conductor. The bifunctional ligand may include a first anchor group that bonds to the quantum dot and a second anchor group that bonds to the electron conductor. The solar cell may include a hole conductor that is configured to reduce the quantum dot once the quantum dot absorbs a photon and ejects an electron through the bifunctional ligand and into the electron conductor. The hole conductor may be a p-type polymer.