Abstract: Photoactive materials comprising organic-inorganic hybrid halide perovskite compounds are provided. Photovoltaic cells and light-emitting devices incorporating the photoactive materials into their light-absorbing and light-emitting layers, respectively, are also provided. The halide perovskites have an amAMX3 perovskite crystal structure, wherein am is an alkyl diamine cation, an aromatic diamine cation, an aromatic azole cation, a cyclic alkyl diamine cation or a hydrazinediium cation; A is a monovalent alkylammonium cation or an alkali metal cation; X is a halide ion or a combination of halide ions; and M is an octahedrally coordinated bivalent metal atom.

Abstract: Composite electrocatalytic materials for catalyzing water splitting are provided. Such materials may comprise a porous, conductive support composed of a transition metal foam, the support having a surface, and a coating on the surface of the support. The coating may comprise nanorods of a first transition metal chalcogenide, each nanorod anchored on one end to the surface of the support and extending perpendicularly away from the surface of the support to a free opposing end, nanosheets of a second transition metal chalcogenide, the nanosheets coating a surface of the nanorods of the first transition metal chalcogenide, and nanosheets of a third transition metal chalcogenide, the nanosheets also coating the surface of the nanorods of the first transition metal chalcogenide.

Abstract: Methods and devices for detecting incident radiation are provided. The methods and devices use high quality single-crystals of photoactive semiconductor compounds in combination with metal anodes and metal cathodes that provide for enhanced photodetector performance.

Abstract: Photoactive materials comprising organic-inorganic hybrid halide perovskite compounds are provided. Photovoltaic cells and light-emitting devices incorporating the photoactive materials into their light-absorbing and light-emitting layers, respectively, are also provided. The halide perovskites have an amAMX3 perovskite crystal structure, wherein am is an alkyl diamine cation, an aromatic diamine cation, an aromatic azole cation, a cyclic alkyl diamine cation or a hydrazinediium cation; A is a monovalent alkylammonium cation or an alkali metal cation; X is a halide ion or a combination of halide ions; and M is an octahedrally coordinated bivalent metal atom.

Abstract: Metal organic resins, composite materials composed of the metal organic resins, and anion exchange columns packed with the composite materials are provided. Also provided are methods of using the composite materials to remove metal anions from a sample, methods of using the metal organic resins as fluorescence sensors for detecting metal anions in a sample, and methods of making the metal organic resins and the composite materials. The metal organic resins are amine-functionalized metal organic frameworks and their associated counter anions. The composite materials are composed of metal organic resin particles coated with organic polymers, such as alginic acid polymers.

Abstract: Two-dimensional halide perovskites are provided. The perovskites have two-dimensional Dion-Jacobson phases and are composed of a plurality of inorganic perovskite layers separated by 3-(aminomethyl)piperidinium (3AMP) and/or 4-(aminomethyl)piperidinium (4AMP) spacer cations. The halide perovskites may have a single perovskitizer cation or mixed perovskitizer cations. Also provided are radiation-absorbing materials comprising the perovskites and photovoltaic cells comprising the radiation-absorbing materials as photoactive materials.

Abstract: Methods for purifying reaction precursors used in the synthesis of inorganic compounds and methods for synthesizing inorganic compounds from the purified precursors are provided. Also provided are methods for purifying the inorganic compounds and methods for crystallizing the inorganic compounds from a melt. ? and X-ray detectors incorporating the crystals of the inorganic compounds are also provided.

Abstract: Inorganic compounds having the formula LiMP2Q6, where M is Ga, In, Bi, Sb, As, Al, or a combination thereof, and Q is S and/or Se, ar provided. Methods and devices for detecting incident neutrons and alpha-particles using the compounds are also provided. For thermal neutron detection applications, the compounds can be enriched with lithium-6 isotope (Li) to enhance their neutron detecting capabilities.

Abstract: Metal organic resins, composite materials composed of the metal organic resins, and anion exchange columns packed with the composite materials are provided. Also provided are methods of using the composite materials to remove metal anions from a sample, methods of using the metal organic resins as fluorescence sensors for detecting metal anions in a sample, and methods of making the metal organic resins and the composite materials. The metal organic resins are amine-functionalized metal organic frameworks and their associated counter anions. The composite materials are composed of metal organic resin particles coated with organic polymers, such as alginic acid polymers.

Abstract: Polypyrrole polymers functionalized with thioanions and methods for their use in metal capture applications are provided. Also provided are methods for making the polypyrroles using anion exchange techniques. The thioanion-functionalized polypyrroles have a conjugated, positively charged backbone of pyrrole units that is charge-balanced with associated thioanions.

Abstract: Methods and devices for detecting incident radiation are provided. The methods and devices use high quality single-crystals of photoactive semiconductor compounds in combination with metal anodes and metal cathodes that provide for enhanced photodetector performance.

Abstract: A semiconductor material having the molecular formula Cu2l2Se6 is provided. Also provided are solid solutions of semiconductor materials having the formulas Cu2lxBr2-xSeyTe6-y and Cu2lxBr2-xSeyS6-y, where 0?x?1 and 0?y?3. Methods and devices that use the semiconductor materials to convert incident radiation into an electric signal are also provided. The devices include optoelectronic and photonic devices, such as photodetectors, photodiodes, and photovoltaic cells.

Abstract: Methods and devices that use alkali metal chalcohalides having the chemical formula A2TeX6, wherein A is Cs or Rb and X is I or Br, to convert hard radiation, such as X-rays, gamma-rays, and/or alpha-particles, into an electric signal are provided. The devices include optoelectronic and photonic devices, such as photodetectors and photodiodes. The method includes exposing the alkali metal chalcohalide material to incident radiation, wherein the material absorbs the incident radiation and electron-hole pairs are generated in the material. A detector is configured to measure a signal generated by the electron-hole pairs that are formed when the material is exposed to incident radiation.

Abstract: Photoactive materials comprising organic-inorganic hybrid halide perovskite compounds are provided. Photovoltaic cells and light-emitting devices incorporating the photoactive materials into their light-absorbing and light-emitting layers, respectively, are also provided. The halide perovskites have an amAMX3 perovskite crystal structure, wherein am is an alkyl diamine cation, an aromatic diamine cation, an aromatic azole cation, a cyclic alkyl diamine cation or a hydrazinediium cation; A is a monovalent alkylammonium cation or an alkali metal cation; X is a halide ion or a combination of halide ions; and M is an octahedrally coordinated bivalent metal atom.

Abstract: Composite ion-exchange materials for use in an ion-exchange column are provided. Also provided are ion-exchange columns packed with the materials and methods for using the materials to remove metal ions from samples, such as waste water samples. The composite ion-exchange materials comprise a composite material comprising a metal chalcogenide and an alginate, wherein the composite material is mixed with a granular material.

Abstract: Methods and devices for detecting incident radiation, such as incident X-rays or gamma-rays, are provided. The methods and devices use single-crystalline mercury chalcoiodide compounds having the formula Hg3Q2I2, where Q represents a chalcogen atom or a combination of chalcogen atoms, as photoelectric materials. Also provided are methods for growing single-crystals of the mercury chalcoiodide compounds using external organic chemical transport agents.

Abstract: Amorphous metal chalcogenides having the formula A2xSnxSb3-xQ6 are provided. In the chalcogenides, A is an alkali metal element, such as K or Cs, and Q is S or Se. The value of x can be in the range from 0.8 to 1. Porous chalcogenide materials made from the amorphous chalcogenides are also provided. These porous materials comprise metal chalcogenides having the formula (AB)2xSnxSb3-xQ6, wherein x is in the range from 0.8 to 1, A and B are two different alkali metal elements, and Q is S or Se.

Abstract: Highly phase-pure, two-dimensional, multilayered organic-inorganic hybrid, halide perovskites are provided. Also provided are optoelectronic devices that incorporate the halide perovskites as photoactive materials.

Abstract: Methods and devices for detecting incident radiation, such as incident x-rays or gamma-rays, are provided. The methods and devices use high purity, high quality single-crystals of inorganic semiconductor compounds having the formula A2P2X6, where A represents Pb or Sn and X represents S or Se, as photoelectric materials.

Abstract: Methods and devices for detecting incident radiation, such as incident X-rays, gamma-rays, and/or alpha particle radiation are provided. The methods and devices use high purity, high quality single-crystals of inorganic semiconductor compounds, including solid solutions, having the formula AB2X5, where A represents Tl or In, B represents Sn or Pb, and X represents Br or I, as photoelectric materials.