Abstract: The present invention relates to mixtures of alkali metal polysulfides and to mixtures of alkali metal polysulfides and alkali metal thiocyanates, to processes for preparation thereof, to the use thereof as heat transfer or heat storage fluids, and to heat transfer or heat storage fluids which comprise the mixtures of alkali metal polysulfides or the mixtures of alkali metal polysulfides and alkali metal thiocyanates.

Abstract: A composition for the transport and storage of heat energy, which comprises alkali metal polysulfides of the formula (Me1(1-x),Me2x)2Sz, where Me1 and Me2 are selected from the group of alkali metals consisting of lithium, sodium, potassium, rubidium and cesium, Me1 is different from Me2 and x is from 0 to 1 and z is from 2.3 to 3.5.

Abstract: The invention relates to a thermoelectrically active p- or n-conductive semiconductor material constituted by a compound of the general formula (I) (PbTe)1?x(Sn2±ySb2±zTe5)x??(I) with 0.0001?x?0.5, 0?y<2 and 0?z<2, wherein 0 to 10% by weight of the compound may be replaced by other metals or metal compounds, wherein the semiconductor material has a Seebeck coefficient of at least |S|?60 ?V/K at a temperature of 25° C. and electrical conductivity of at least 150 S/cm and power factor of at least 5 ?W/(cm·K2), further relates to a process for the preparation of such semiconductor materials, as well as to generators and Peltier arrangements containing them.

Abstract: The invention relates to a photovoltaic cell comprising a photovoltaically active semiconductor material, wherein the photovoltaically active semiconductor material is a p- or n-doped semiconductor material comprising a binary compound of the formula (I) or a ternary compound of the formula (II): ZnTe??(I) Zn1-xMnxTe??(II) where x is from 0.01 to 0.99, and a particular proportion of tellurium ions in the photovoltaically active semiconductor material has been replaced by halogen ions and nitrogen ions and the halogen ions are selected from the group consisting of fluoride, chloride and bromide and mixtures thereof.

Abstract: For a process for reducing the thermal conductivity and for increasing the thermoelectric efficiency of thermoelectric materials based on lead chalcogenides or skutterudites, the thermoelectric materials are extruded at a temperature below their melting point and a pressure in the range from 300 to 1 000 MPa.

Abstract: The invention relates to a photovoltaic cell comprising a photovoltaically active semiconductor material, wherein the photovoltaically active semiconductor material is a p- or n-doped semiconductor material comprising mixed compounds of the formula (I): (Zn1?xMnxTe)1?y(SiaTeb)y ??(I) where x is from 0.01 to 0.99, y is from 0.01 to 0.2, a is from 1 to 2 and b is from 1 to 3.

Abstract: The invention relates to a photovoltaic cell comprising a photovoltaically active semiconductor material, wherein the photovoltaically active semiconductor material is a p- or n-doped semiconductor material comprising a binary compound of the formula (I) or a ternary compound of the formula (II): ZnTe??(I) Zn1-xMnxTe??(II) where x is from 0.01 to 0.99, and a particular proportion of tellurium ions in the photovoltaically active semiconductor material has been replaced by halogen ions and nitrogen ions and the halogen ions are selected from the group consisting of fluoride, chloride and bromide and mixtures thereof.

Abstract: The invention relates to a capacitor having a porous electrically conductive substrate on whose inner and outer surfaces a first layer of a dielectric and an electrically conductive second layer are applied. The invention also relates to a method for the production of such capacitors and to their use in electrical and electronic circuits.

Abstract: The invention relates to a photovoltaically active semiconductor material and a photovoltaic cell comprising a photovoltaically active semiconductor material, wherein the photovoltaically active semiconductor material contains a crystal lattice composed of zinc telluride and, in the zinc telluride crystal lattice, ZnTe is substituted by—0.01 to 10 mol % CoTe, —0 to 10 mol % Cu2Te, Cu3Te or CuTe and —0 to 30 mol % of at least one compound selected from the group MgTe and MnTe, and wherein, in the zinc telluride crystal lattice Te is substituted by—0.1 to 30 mol % oxygen. The photovoltaic cell furthermore has a rear contact composed of a rear contact material that forms a metal telluride with tellurium.

Abstract: The invention relates to photonic crystals which have units having a refractive index of greater than 3 and units having a refractive index of less than 1.6 in a periodic sequence and separations of the individual units of from 1 to 20 ?m, and also to the use of these photonic crystals.

Abstract: The invention relates to a photovoltaic cell comprising a photovoltaically active semiconductor material, wherein the photovoltaically active semiconductor material is a material of the formula (I), of the formula (II) or of a combination thereof: (Zn1-xMgxTe)1-y(MnTem)y and ??(I) (ZnTe)1-y(MeaMb)y, where ??(II) MnTem and MeaMb are each a dopant in which M is at least one element selected from the group consisting of Si, Ge, Sn. Pb, Sb and Bi and Me is at least one element selected from the group consisting of mg and Zn, and x=0 to 0.5 y=0.0001 to 0.05 n=1 to 2 m=0.5 to 4 a=1 to 5 and b=1 to 3.

Abstract: The invention relates to a photovoltaic cell and to a process for producing a photovoltaic cell comprising a photovoltaically active semiconductor material of the formula (I) or (II): ZnTe ??(I) Zn1-xMnxTe ??(II) where x is from 0.01 to 0.

Abstract: Process for preparing nanocrystalline lithium titanate spinels by reacting lithium hydroxide and a titanium alkoxide at elevated temperature in a reaction mixture which forms water of reaction.

Abstract: The invention relates to the thermally stable contacting of semiconductive alloys for use in thermoelectric generators and Peltier arrangements by means of soldering, and to processes for producing thermoelectric modules using a barrier layer composed of borides, nitrides, carbides, phosphides and/or silicides.

Abstract: Iron pentacarbonyl is prepared by reacting iron with carbon monoxide in suspension and in the presence of a mixture of alkali metal sulfide and sulfur as a catalyst.

Abstract: A thermoelectrically active p- or n-conductive semiconductor material is constituted by a ternary compound of the general formula (I) (Pb1-xGex)Te??(I) with x value from 0.16 to 0.5, wherein 0 to 10% by weight of the ternary compound may be replaced by other metals or metal compounds, wherein the semiconductor material has a Seebeck coefficient of at least ±200 ?V/K at a temperature of 25° C.

Abstract: The rod-shaped apatite crystals of the formula Ca5(PO4)3(OH)xFy have the following features a) the length-to-breadth ratio of the crystals is at least ?5 and b) x+y=1, where if x or y?0 the total amount of the crystals is present as a mixture of individual hydroxyapatite crystals and fluoroapatite crystals and/or as mixed crystals, such that, based on the total amount of the crystals, (1?x)·100% of the hydroxide ions present if y=0 are replaced by fluoride ions. The invention furthermore describes dispersions which contain such rod-shaped apatite crystals, and a process for the preparation of the dispersions or of the apatite crystals.

Abstract: The invention relates to a thermoelectrically active p- or n-conductive semiconductor material constituted by a compound of the general formula (I) (PbTe)1-x(Sn2±ySb2±zTe5)x ??(I) with 0.0001?x?0.5, 0?y<2 and 0?z<2, wherein 0 to 10% by weight of the compound may be replaced by other metals or metal compounds, wherein the semiconductor material has a Seebeck coefficient of at least |S|?60 ?V/K at a temperature of 25° C. and electrical conductivity of at least 150 S/cm and power factor of at least 5 ?W/(cm·K2), further relates to a process for the preparation of such semiconductor materials, as well as to generators and Peltier arrangements containing them.

Abstract: Iron pentacarbonyl is prepared by reacting iron with carbon monoxide in suspension and in the presence of a polysulfide of the general formula RSxR? as a catalyst, where R is an organic radical and x is a number from 2 to 8.

Abstract: Process for preparing barium titanate or strontium titanate by reacting titanium alkoxides with barium hydroxide hydrate or strontium hydroxide hydrate in a C1–C8-alcohol or a glycol ether at from 50 to 150° C.