Thermoelectric state

Table 2. Summary of Radioisotope Thermoelectric Generators Successfully Launched by the United States from 1961 to 1990...

Titles K, Bund A, Plieth W, Bentien A, Paschen S, Pldttner M, Grafe H, Fischer WJ (2003) Electrochemical deposition of Bi2Te3 for thermoelectric microdevices. J Solid State Electrochem 7 714-723... 

Tittes K, Plieth W (2007) Electrochemical deposition of ternary and binary systems from an alkaline electrolyte—a demanding way for manufacturing p-doped bismuth and antimony teUurides for the use in thermoelectric elements. J Solid State Electrochem 11 155-164... 

Radioisotope thermoelectric generators (RTGs) are sometimes used as power sources for space systems. In April 1964, a United States RTG navigational satellite, SNAP 9A, reentered the atmosphere and burned up at high altitude over the Mozambique Channel, releasing 629 trillion becquerels (TBq), equivalent to 17,000 Ci, of Pu and 0.48 TBq of Pu (Whicker and Schultz 1982a Richmond 1989). In January 1978, a Soviet RTG satellite, Kosmos 954, reentered the atmosphere over Canada and spread radiouranium across parts of that country (Richmond 1989). The amount of radioactive materials in space applications is expected to increase (Richmond 1989). 

A second historical line which, is of paramount importance to the present understanding of solid state processes is concerned with electronic particles (defects) rather than with atomic particles (defects). Let us therefore sketch briefly the, history of semiconductors [see H. J, Welker (1979)]. Although, the term semiconductor was coined in 1911 [J. KOnigsberger, J, Weiss (1911)], the thermoelectric effect had already been discovered almost one century earlier [T. J. Seebeck (1822)], It was found that PbS and ZnSb exhibited temperature-dependent thermopowers, and from todays state of knowledge use had been made of n-type and p-type semiconductors. Faraday and Hittorf found negative temperature coefficients for the electrical conductivities of AgzS and Se. In 1873, the decrease in the resistance of Se when irradiated by visible light was reported [W. Smith (1873) L. Sale (1873)]. It was also... 

The metallic nature of concentrated metal-ammonia solutions is usually called "well known." However, few detailed studies of this system have been aimed at correlating the properties of the solution with theories of the liquid metallic state. The role of the solvated electron in the metallic conduction processes is not yet established. Recent measurements of optical reflectivity and Hall coefficient provide direct determinations of electron density and mobility. Electronic properties of the solution, including electrical and thermal conductivities, Hall effect, thermoelectric power, and magnetic susceptibility, can be compared with recent models of the metallic state. 

ZT Y r A A A A A AC dimensionless thermoelectric figure of merit electronic coefficient of heat capacity (1+ZT)F2 crystal field singlet non-Kramers doublet (crystal field state) crystal field triplet crystal field triplet hybridization gap jump in heat capacity at Tc K KL -min P 6>d X JCO total thermal conductivity of solid thermal conductivity of electrons or holes thermal conductivity of lattice minimum lattice thermal conductivity electrical resistivity Debye temperature magnetic susceptibility magnetic susceptibility at T = 0... 

Fig. 23. ZT vs. T for several state-of-the-art thermoelectric materials and for a filled skutterudite with x 1. (Figure from T.M. Tritt, unpublished.)...

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