Abstract: A system for low power chemical sensing can include a voltage shift unit which receives a voltage signal from a chemical sensor unit. The voltage signal can be determined by a concentration of an analyte. The voltage shift unit can transform the voltage signal to an input voltage signal, and send the input voltage signal to a plurality of frequency selective surface (FSS) units of an FSS array. The FSS array can communicate a radio frequency (RF) signal in an Institute of Electrical and Electronics Engineers (IEEE) S band with a resonant frequency based on the input voltage to provide the concentration of the analyte.

Abstract: Methods of detecting a non-explosive analyte can include exposing a sensor compound to a non-explosive analyte and displaying a change in the sensor compound upon exposure of the sensor compound to the non-explosive analyte. A variety of sensor compounds for detecting a target analyte, including both explosive and non-explosive analytes, is also described. Sensor devices for detecting a target analyte can include a substrate and a sensor compound positioned on the substrate in a plurality of detection zones.

Abstract: Methods of detecting a non-explosive analyte can include exposing a sensor compound to a non-explosive analyte and displaying a change in the sensor compound upon exposure of the sensor compound to the non-explosive analyte. A variety of sensor compounds for detecting a target analyte, including both explosive and non-explosive analytes, is also described. Sensor devices for detecting a target analyte can include a substrate and a sensor compound positioned on the substrate in a plurality of detection zones.

Abstract: A sensor to detect solid particles of a target salt can include a support substrate, an adsorption layer, a sensing layer oriented between the support substrate and the adsorption layer, and an electrode pair in contact with the sensing layer and separated by the sensing layer. The adsorption layer can include an ion exchange medium formed of a first porous structured material functionalized with basic or acidic functional groups. The basic or acidic functional groups can remove an acid or base component from the target salt to form a free base or free acid, respectively, of the target salt. The sensing layer can include a second porous structured material functionalized to detect the free base or acid of the target salt by a change in conductivity.

Abstract: A chemiresistive vapor sensor compound for detecting target vapors can comprise a perylene-tetracarboxylic diimide (PTCDI) core according to structure (I): where R can be a morphology control group or -A?-D?, A and A? can be independently a linking group, D and D? can be independently a strong electron donor which transfers electrons to the PTCDI core sufficient to form an anionic PTCDI radical of the PTCDI core, and R1 to R8 can be independently a side group. A chemiresistive vapor sensor for detection of a target compound can comprise an assembly of nanofibers formed of the chemiresistive sensor compound and a pair of electrodes operatively oriented about the assembly of nanofibers to allow electrical current to pass from a first electrode in the pair of electrodes through the assembly of nanofibers and to a second electrode in the pair of electrodes.

Abstract: Methods of detecting a non-explosive analyte can include exposing a sensor compound to a non-explosive analyte and displaying a change in the sensor compound upon exposure of the sensor compound to the non-explosive analyte. A variety of sensor compounds for detecting a target analyte, including both explosive and non-explosive analytes, is also described. Sensor devices for detecting a target analyte can include a substrate and a sensor compound positioned on the substrate in a plurality of detection zones.

Abstract: A multimode gas sensor platform can comprise an array of electrode pairs oriented on a substrate and a plurality of detection zones, wherein at least a portion of individual electrode pairs are separately addressable. Each detection zone can comprise at least one set of individual electrode pairs within the array, where the individual electrode pairs have organic nanofibers uniformly deposited thereon. The organic nanofibers can be responsive to association with a corresponding target material and at least one detection zone can be electronically responsive to the corresponding target material.

Abstract: A system for low power chemical sensing can include a voltage shift unit which receives a voltage signal from a chemical sensor unit. The voltage signal can be determined by a concentration of an analyte. The voltage shift unit can transform the voltage signal to an input voltage signal, and send the input voltage signal to a plurality of frequency selective surface (FSS) units of an FSS array. The FSS array can communicate a radio frequency (RF) signal in an Institute of Electrical and Electronics Engineers (IEEE) S band with a resonant frequency based on the input voltage to provide the concentration of the analyte.

Abstract: A nanofiber composite sensor for detecting alkanes can include a network of contacting nanofibers having multiple contact points. Each contact point can form an interfiber interface of interdigitated alkyl chains. Alkanes can be adsorbed at the interfiber interface which results in an increased interfiber distance between first and second nanofibers and a decreased charge transfer efficiency. The detected alkanes can be in a vapor or liquid phase.

Abstract: A sensory material with high sensitivity, selectivity, and photostability has been developed for vapor probing of organic amines. The sensory material is a perylene-3,4,9,10-tetracarboxyl compound having amine binding groups and the following formula where A and A? are independently chosen from N—R1, N—R2, and O such that both A and A? are not O, and R1 through R10 are amine binding moieties, solubility enhancing groups, or hydrogen such that at least one of R1 through R10 is an amine binding moiety. This perylene compound can be formed into well-defined nanofibers. Upon deposition onto a substrate, the entangled nanofibers form a meshlike, highly porous film, which enables expedient diffusion of gaseous analyte molecules within the film matrix, leading to a milliseconds response for vapor sensing.

Abstract: A method for thermally induced recrystallization of a film having a perovskite structure can include exposing the perovskite structure to a liquid phase induction atmosphere sufficient to at least partially liquefy the film. The substrate with the film can be heated while in the atmosphere to a heating temperature above a critical recrystallization temperature until the film recrystallizes to reform the perovskite structure with reduced defects and increased grain size. The liquid phase induction atmosphere can be purged, and the substrate with the film having the reformed perovskite structure can be allowed to cool. The film having the perovskite structure can have a formula ABX3, (RA)2An?1BnX3n+1, or (RA2)An?1BnX3n+1, where A is a monovalent cation, B is divalent metal cation, n is an integer, X is a halide ion, RA is an alkylammonium cation and RA2 is an alkyldiammonium cation.

Abstract: A chemical sensing field effect transistor device is disclosed. The device can include a control gate structure interfacing a control side of a semiconductor channel region, a source region, and a drain region. The control gate structure can comprise a control gate dielectric and a control gate electrode. The device can include a sensing gate structure interfacing the semiconductor channel region, the source region, and the drain region at a sensing side of the semiconductor channel region opposite the control gate structure. The sensing gate structure can comprise a sensing gate dielectric, and a sensing gate electrode. The device can include a functional layer interfacing the sensing gate electrode opposite the sensing gate dielectric. The functional layer can have an exposed interface surface. The functional layer can be capable of binding with a target analyte material sufficient to create a measurable change in conductivity across the semiconductor channel region.

Abstract: Methods of detecting a non-explosive analyte can include exposing a sensor compound to a non-explosive analyte and displaying a change in the sensor compound upon exposure of the sensor compound to the non-explosive analyte. A variety of sensor compounds for detecting a target analyte, including both explosive and non-explosive analytes, is also described. Sensor devices for detecting a target analyte can include a substrate and a sensor compound positioned on the substrate in a plurality of detection zones.

Abstract: A sensory material with high sensitivity, selectivity, and photostability has been developed for vapor probing of organic amines. The sensory material is a perylene-3,4,9,10-tetracarboxyl compound having amine binding groups and the following formula where A and A? are independently chosen from N—R1, N—R2, and O such that both A and A? are not O, and R1 through R10 are amine binding moieties, solubility enhancing groups, or hydrogen such that at least one of R1 through R10 is an amine binding moiety. This perylene compound can be formed into well-defined nanofibers. Upon deposition onto a substrate, the entangled nanofibers form a meshlike, highly porous film, which enables expedient diffusion of gaseous analyte molecules within the film matrix, leading to a milliseconds response for vapor sensing.

Abstract: The present disclosure provides methods and compositions for an organic nanofiber-based heterojunction material, comprising nano fibers of an acceptor molecule, the nano fibers coated with a donor molecule, where the acceptor molecule contains a group and the donor molecule contains a companion group, wherein the group and companion group enables strong binding between the acceptor molecule and donor molecule, the strong binding providing for efficient forward electron transfer between the acceptor molecule and donor molecule, and wherein the group and companion group minimize charge carrier recombination between the acceptor molecule and the donor molecule.

Abstract: A chemiresistive vapor sensor compound for detecting target vapors can comprise a perylene-tetracarboxylic diimide (PTCDI) core according to structure (I): where R can be a morphology control group or -A?-D?, A and A? can be independently a linking group, D and D? can be independently a strong electron donor which transfers electrons to the PTCDI core sufficient to form an anionic PTCDI radical of the PTCDI core, and R1 to R8 can be independently a side group. A chemiresistive vapor sensor for detection of a target compound can comprise an assembly of nanofibers formed of the chemiresistive sensor compound and a pair of electrodes operatively oriented about the assembly of nanofibers to allow electrical current to pass from a first electrode in the pair of electrodes through the assembly of nanofibers and to a second electrode in the pair of electrodes.

Abstract: A nanofiber composite sensor for detecting alkanes can include a network of contacting nanofibers having multiple contact points. Each contact point can form an interfiber interface of interdigitated alkyl chains. Alkanes can be adsorbed at the interfiber interface which results in an increased interfiber distance between first and second nanofibers and a decreased charge transfer efficiency. The detected alkanes can be in a vapor or liquid phase.

Abstract: A chemical sensing field effect transistor device is disclosed. The device can include a control gate structure interfacing a control side of a semiconductor channel region, a source region, and a drain region. The control gate structure can comprise a control gate dielectric and a control gate electrode. The device can include a sensing gate structure interfacing the semiconductor channel region, the source region, and the drain region at a sensing side of the semiconductor channel region opposite the control gate structure. The sensing gate structure can comprise a sensing gate dielectric, and a sensing gate electrode. The device can include a functional layer interfacing the sensing gate electrode opposite the sensing gate dielectric. The functional layer can have an exposed interface surface. The functional layer can be capable of binding with a target analyte material sufficient to create a measurable change in conductivity across the semiconductor channel region.

Abstract: Methods, compositions, and systems for detecting gamma radiation is disclosed and described. A compound for detecting gamma radiation can comprise a conjugated imidazole having the following structure: [Formula I] where at least one of R1, R2, and R3 are conjugated organic groups. Additionally, the conjugated imidazole can be capable of reacting with a radical or ion formed by the reaction of gamma radiation with a radical generating component such as a halogen solvent to decrease a molar extinction coefficient of the conjugated imidazole in the visible light region or to quench fluorescence of the conjugated imidazole. As a sensor (100), a radiation detection indicator (108) can indicate the change in molar extinction coefficient or fluorescence of the conjugated imidazole material (120) upon exposure to gamma radiation.

Abstract: Described herein are the preparation and use of metal sensor compounds in detecting metals that are toxic to humans or to the environment. In one aspect, the metal sensor compounds comprise a polycyclic aryl group (PAC), wherein at least one solubilizing group and at least one metal binding ligand are covalently bonded to (PAC).