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Prospective Thermoelectric Tellurides

Prospective Thermoelectric Tellurides

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Prospective Thermoelectric Tellurides

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  1. E2.1.8x6761 Prospective Thermoelectric Tellurides Patrik Čermák University of Pardubice, Czech Republic

  2. „Thermoelectrics as an ‘energy gate’ to deep space“ Space probes (e.g.): • Voyager 1, 2 (1977) • Galileo (1989) • Ulysses (1990) • Cassiny (1997) • New Horizons (2006)

  3. Seebeck effect2. Peltier effect Thermoelectric materials The main aim of researching of TE materials in general is enhance their efficiency in defined temperature range. Heating Cooling + - + - - - + p-type n-type + Q - p-type n-type - + + - - - - + U I. Introduction to Thermoelectrics Performance criterion forpractical applications:

  4. II. Research Motivation • Optimize of figure of merit ZT of n-type Bi2+xTe3-x-y-zSeyIz polycrystalline systemfor enhance of efficiency of Peltier elements in room temperature range (300 K). • Preparation of „novel TE material – GaGeTe“with enhanced electrical conductivitys(focuse on figure of merit ZT) and development of complementary n-type. Bi2Te3 Characterization • X-ray Diffraction • Seebeck coefficient a(Tc) • Electrical conductivity sc • Thermal conductivity k • Hall coefficient RH (B║c) GaGeTe

  5. III. Results Bi2+xTe3-x-y-zSeyIz GaGeTe1-xIx 430 K

  6. Substitution of „Te“ for „I“ - Bi2+xTe3-x-y-zSeyIz: n s a a n a T IV. Discussion Bi2+xTe3-x-y-zSeyIz The samples with tetradymite structure were prepared. For optimization of TE properties (focused on figure of merit ZT) was examined the influence of iodine by doping classical Bismuth-Telluride (Bi2Te3). Iodine +1-e than Tellurium  increment of the concentration of free charge carriers: GaGeTe1-xIx This (ternary) system show high Seebeck coefficient then the state-of-the-art materials. Is it a p-type semiconductor  n-type = more –e. I have prepared substitute compound TeI4 and doped the GaGeTe. XRD shows minimal content of other phases  successful doping.

  7. V. Conclusions Bi2+xTe3-x-y-zSeyIz The character of the optimize TE material is possible to expect at Bi2Te2,9Se0,096I0,004 – lower concentration of iodine but also . Now will follows the measurements of the other TE properties including „certainty“ identifications by XRD. GaGeTe1-xIx The first results promising great potential of this „novel ternary telluride“. Will follows the continual research consists from: (1) increment value of iodine for development complementary n-type, (2) doping by another elements which can increment value of electrical conductivity (e.g. create defects of positive charge) and then optimized its TE efficiency (parameter ZT).

  8. Thank you for your attention

  9. References for this presentation Image „Stargate SG-1“ [1]www.trekkies.cz Images of the space probes [2]www.nasa.gov, www.wikipedia.org Image „Radioisotope Missions“ [3]www.thermoelectrics.caltech.edu Patrik Čermák E-mail: patrik.cermak@email.cz