Names | |
---|---|
Other names Lead(II) telluride Altaite | |
Identifiers | |
ChemSpider | |
ECHA InfoCard | 100.013.862 |
EC Number |
|
PubChem CID | |
UNII | |
CompTox Dashboard (EPA) | |
Properties | |
PbTe | |
Molar mass | 334.80 g/mol |
Appearance | gray cubic crystals. |
Density | 8.164 g/cm3 |
Melting point | 924 °C (1,695 °F; 1,197 K) |
insoluble | |
Band gap | 0.25 eV (0 K) 0.32 eV (300 K) |
Electron mobility | 1600 cm2 V−1 s−1 (0 K) 6000 cm2 V−1 s−1 (300 K) |
Structure | |
Halite (cubic), cF8 | |
Fm3m, No. 225 | |
a = 6.46 Angstroms | |
Octahedral (Pb2+) Octahedral (Te2−) | |
Thermochemistry | |
Std molar entropy (S⦵298) | 50.5 J·mol−1·K−1 |
Std enthalpy of formation (ΔfH⦵298) | -70.7 kJ·mol−1 |
Std enthalpy of combustion (ΔcH⦵298) | 110.0 J·mol−1·K−1 |
Hazards | |
GHS labelling: | |
Danger | |
H302, H332, H351, H360, H373, H410 | |
P201, P202, P260, P261, P264, P270, P271, P273, P281, P301+P312, P304+P312, P304+P340, P308+P313, P312, P314, P330, P391, P405, P501 | |
Flash point | Non-flammable |
Safety data sheet (SDS) | External MSDS |
Related compounds | |
Other anions | Lead(II) oxide Lead(II) sulfide Lead selenide |
Other cations | Carbon monotelluride Silicon monotelluride Germanium telluride Tin telluride |
Related compounds | Thallium telluride Bismuth telluride |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
Lead telluride is a compound of lead and tellurium (PbTe). It crystallizes in the NaCl crystal structure with Pb atoms occupying the cation and Te forming the anionic lattice. It is a narrow gap semiconductor with a band gap of 0.32 eV. [4] It occurs naturally as the mineral altaite.
PbTe has proven to be a very important intermediate thermoelectric material. The performance of thermoelectric materials can be evaluated by the figure of merit, , in which is the Seebeck coefficient, is the electrical conductivity and is the thermal conductivity. In order to improve the thermoelectric performance of materials, the power factor () needs to be maximized and the thermal conductivity needs to be minimized. [5]
The PbTe system can be optimized for power generation applications by improving the power factor via band engineering. It can be doped either n-type or p-type with appropriate dopants. Halogens are often used as n-type doping agents. PbCl2, PbBr2 and PbI2 are commonly used to produce donor centers. Other n-type doping agents such as Bi2Te3, TaTe2, MnTe2, will substitute for Pb and create uncharged vacant Pb-sites. These vacant sites are subsequently filled by atoms from the lead excess and the valence electrons of these vacant atoms will diffuse through crystal. Common p-type doping agents are Na2Te, K2Te and Ag2Te. They substitute for Te and create vacant uncharged Te sites. These sites are filled by Te atoms which are ionized to create additional positive holes. [6] With band gap engineering, the maximum zT of PbTe has been reported to be 0.8 - 1.0 at ~650K.
Collaborations at Northwestern University boosted the zT of PbTe by significantly reducing its thermal conductivity using ‘all-scale hierarchical architecturing'. [7] With this approach, point defects, nanoscale precipitates and mesoscale grain boundaries are introduced as effective scattering centers for phonons with different mean free paths, without affecting charge carrier transport. By applying this method, the record value for zT of PbTe that has been achieved in Na doped PbTe-SrTe system is approximately 2.2. [8]
In addition, PbTe is also often alloyed with tin to make lead tin telluride, which is used as an infrared detector material.
Tellurium is a chemical element; it has symbol Te and atomic number 52. It is a brittle, mildly toxic, rare, silver-white metalloid. Tellurium is chemically related to selenium and sulfur, all three of which are chalcogens. It is occasionally found in its native form as elemental crystals. Tellurium is far more common in the Universe as a whole than on Earth. Its extreme rarity in the Earth's crust, comparable to that of platinum, is due partly to its formation of a volatile hydride that caused tellurium to be lost to space as a gas during the hot nebular formation of Earth.
Electrical resistivity is a fundamental specific property of a material that measures its electrical resistance or how strongly it resists electric current. A low resistivity indicates a material that readily allows electric current. Resistivity is commonly represented by the Greek letter ρ (rho). The SI unit of electrical resistivity is the ohm-metre (Ω⋅m). For example, if a 1 m3 solid cube of material has sheet contacts on two opposite faces, and the resistance between these contacts is 1 Ω, then the resistivity of the material is 1 Ω⋅m.
Thermoelectric cooling uses the Peltier effect to create a heat flux at the junction of two different types of materials. A Peltier cooler, heater, or thermoelectric heat pump is a solid-state active heat pump which transfers heat from one side of the device to the other, with consumption of electrical energy, depending on the direction of the current. Such an instrument is also called a Peltier device, Peltier heat pump, solid state refrigerator, or thermoelectric cooler (TEC) and occasionally a thermoelectric battery. It can be used either for heating or for cooling, although in practice the main application is cooling. It can also be used as a temperature controller that either heats or cools.
Thermoelectric materials show the thermoelectric effect in a strong or convenient form.
In solid-state physics, the electron mobility characterises how quickly an electron can move through a metal or semiconductor when pulled by an electric field. There is an analogous quantity for holes, called hole mobility. The term carrier mobility refers in general to both electron and hole mobility.
The Seebeck coefficient of a material is a measure of the magnitude of an induced thermoelectric voltage in response to a temperature difference across that material, as induced by the Seebeck effect. The SI unit of the Seebeck coefficient is volts per kelvin (V/K), although it is more often given in microvolts per kelvin (μV/K).
In physics, the Wiedemann–Franz law states that the ratio of the electronic contribution of the thermal conductivity (κ) to the electrical conductivity (σ) of a metal is proportional to the temperature (T).
The telluride ion is the anion Te2− and its derivatives. It is analogous to the other chalcogenide anions, the lighter O2−, S2−, and Se2−, and the heavier Po2−.
Lead selenide (PbSe), or lead(II) selenide, a selenide of lead, is a semiconductor material. It forms cubic crystals of the NaCl structure; it has a direct bandgap of 0.27 eV at room temperature. A grey solid, it is used for manufacture of infrared detectors for thermal imaging. The mineral clausthalite is a naturally occurring lead selenide.
Tin selenide, also known as stannous selenide, is an inorganic compound with the formula SnSe. Tin(II) selenide is a typical layered metal chalcogenide as it includes a group 16 anion (Se2−) and an electropositive element (Sn2+), and is arranged in a layered structure. Tin(II) selenide is a narrow band-gap (IV-VI) semiconductor structurally analogous to black phosphorus. It has received considerable interest for applications including low-cost photovoltaics, and memory-switching devices.
A thermoelectric generator (TEG), also called a Seebeck generator, is a solid state device that converts heat directly into electrical energy through a phenomenon called the Seebeck effect. Thermoelectric generators function like heat engines, but are less bulky and have no moving parts. However, TEGs are typically more expensive and less efficient.
The McCumber relation is a relationship between the effective cross-sections of absorption and emission of light in the physics of solid-state lasers. It is named after Dean McCumber, who proposed the relationship in 1964.
Heat transfer physics describes the kinetics of energy storage, transport, and energy transformation by principal energy carriers: phonons, electrons, fluid particles, and photons. Heat is energy stored in temperature-dependent motion of particles including electrons, atomic nuclei, individual atoms, and molecules. Heat is transferred to and from matter by the principal energy carriers. The state of energy stored within matter, or transported by the carriers, is described by a combination of classical and quantum statistical mechanics. The energy is different made (converted) among various carriers. The heat transfer processes are governed by the rates at which various related physical phenomena occur, such as the rate of particle collisions in classical mechanics. These various states and kinetics determine the heat transfer, i.e., the net rate of energy storage or transport. Governing these process from the atomic level to macroscale are the laws of thermodynamics, including conservation of energy.
Oxyselenides are a group of chemical compounds that contain oxygen and selenium atoms. Oxyselenides can form a wide range of structures in compounds containing various transition metals, and thus can exhibit a wide range of properties. Most importantly, oxyselenides have a wide range of thermal conductivity, which can be controlled with changes in temperature in order to adjust their thermoelectric performance. Current research on oxyselenides indicates their potential for significant application in electronic materials.
Molybdenum(IV) telluride, molybdenum ditelluride or just molybdenum telluride is a compound of molybdenum and tellurium with formula MoTe2, corresponding to a mass percentage of 27.32% molybdenum and 72.68% tellurium.
Lead tin telluride, also referred to as PbSnTe or Pb1−xSnxTe, is a ternary alloy of lead, tin and tellurium, generally made by alloying either tin into lead telluride or lead into tin telluride. It is a IV-VI narrow band gap semiconductor material.
Tellurium compounds are compounds containing the element tellurium (Te). Tellurium belongs to the chalcogen family of elements on the periodic table, which also includes oxygen, sulfur, selenium and polonium: Tellurium and selenium compounds are similar. Tellurium exhibits the oxidation states −2, +2, +4 and +6, with +4 being most common.
Mercouri Kanatzidis is a Charles E. and Emma H. Morrison Professor of chemistry and professor of materials science and engineering at Northwestern University and Senior Scientist at Argonne National Laboratory.
Robert P. H. Chang is an American materials scientist who served as the president of the Materials Research Society (1989) and as a general secretary and president of the International Union of Materials Research Societies (IUMRS). Currently Chang heads the Materials Research Institute at Northwestern University. He is a member of advisory boards of the National Institute for Materials Science and of the journal Science and Technology of Advanced Materials.
Tellurogallates are chemical compounds which contain anionic units of tellurium connected to gallium. They can be considered as gallates where tellurium substitutes for oxygen. Similar compounds include the thiogallates, selenogallates, telluroaluminates, telluroindates and thiostannates. They are in the category of chalcogenotrielates or more broadly tellurometallates or chalcogenometallates.
This article needs additional citations for verification .(May 2009) |