• Article  

      Nanostructure and doping stimulated phase separation in high-ZT Mg2Si0.55Sn0.4Ge0.05 compounds 

      Polymeris, G. S.; Vlachos, N.; Khan, A. U.; Hatzikraniotis, E.; Lioutas, C. B.; Delimitis, A.; Pavlidou, E.; Paraskevopoulos, K. M.; Kyratsi, Theodora (2015)
      A study was attempted on the structural properties across all relevant length-scales for Mg2(Si,Sn,Ge)-type solid solutions of the formula Mg2Si0.55- ySn0.40Ge0.05(Bi,Sb)y. The study focuses on three families of samples, ...
    • Conference Object  

      On the optical properties of thermoelectric alkali metal chalcogenide compounds 

      Hatzikraniotis, E.; Kyratsi, Theodora; Zorba, T.; Paraskevopoulos, K. M.; Kanatzidis, M. G. (Affiliation: Physics Department, Aristotle University of Thessaloniki, 54124 Thessaloniki, GreeceAffiliation: Department of Chemistry, Michigan State University, East Lansing, MI 48824, United StatesAffiliation: Department of Mechanical and Manufacturing Engineering, University of Cyprus, 1678 Nicosia, CyprusCorrespondence Address: Hatzikraniotis, E.Physics Department, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece, 2006)
      Solid solutions of K2Bi8-xSbxSe 13 is an interesting series of complex bismuth-chalcogenide compounds, which are attractive for thermoelectric investigations. The highly anisotropic structure in these compounds results in ...
    • Conference Object  

      On the use of thermoelectric (TE) applications based on commercial modules: The case of TE generator and TE cooler 

      Zorbas, K.; Hatzikraniotis, E.; Paraskevopoulos, K. M.; Kyratsi, Theodora (Department of Physics, Aristotle University of Thessaloniki, GreeceDepartment of Mechanical and Manufacturing Engineering, University of Cyprus, Nicosia, CyprusCorrespondence Address: Zorbas, K.Department of Physics, Aristotle University of ThessalonikiGreece, 2010)
      In recent years, thermoelectricity sees rapidly increasing usages in applications like portable refrigerators, beverage coolers, electronic component coolers etc. when used as Thermoelectric Cooler (TEC), and Thermoelectric ...
    • Article  

      Optimization of thermoelectric properties of Bi2Se3 using insertion techniques 

      Kyratsi, Theodora; Hatzikraniotis, E.; Chrissafis, K.; Paraskevopoulos, K. M. (1998)
      In this work we investigate the optimization of the performance of thermoelectric materials using insertion techniques. Our results indicate that in cases such as Bi2Se3 compounds, where insertion of foreign species in the ...
    • Article  

      Seebeck and thermal conductivity analysis in amorphous/crystalline β-K2Bi8Se13 nanocomposite materials 

      Kyratsi, Theodora; Hatzikraniotis, E.; Ioannou, M.; Chung, D. Y.; Tsiaoussis, I. (2018)
    • Conference Object  

      Sintering process in ball-milled K2Bi8Se13 nano-composites 

      Ioannou, M.; Hatzikraniotis, E.; Lioutas, C.; Chrissafis, K.; Chung, D. Y.; Paraskevopoulos, K. M.; Kyratsi, Theodora (Affiliation: Department of Mechanical and Manufacturing Engineering, University of Cyprus, 1678 Nicosia, CyprusAffiliation: Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki, GreeceAffiliation: Materials Science Division, Argonne National Laboratory, Argonne, IL 60439, United StatesCorrespondence Address: Ioannou, M.Department of Mechanical and Manufacturing Engineering, University of Cyprus, 1678 Nicosia, Cyprus, 2012)
      K2Bi8Se13 material has many attractive features for thermoelectric applications. Recently, K2Bi 8Se13 based nanocomposite materials, consisting of nano-crystalline, micro-crystalline and amorphous phases, have been fabricated ...
    • Article  

      Solid-state synthesis and thermoelectric properties of Sb-doped Mg 2Si materials 

      Ioannou, M.; Polymeris, G.; Hatzikraniotis, E.; Khan, A. U.; Paraskevopoulos, K. M.; Kyratsi, Theodora (2013)
      Sb-doped magnesium silicide compounds have been prepared through ball milling and solid-state reaction. Materials produced were near-stoichiometric. The structural modifications have been studied with powder x-ray diffraction. ...
    • Article  

      Structural features of ball-milled nanostructured K2Bi 8Se13 thermoelectric material 

      Lioutas, C. B.; Hatzikraniotis, E.; Ioannou, M.; Paraskevopoulos, K. M.; Kyratsi, Theodora (2011)
      In this work, K2Bi8Se13 material was ball-milled in order to develop nanostructures through the modification of structural features. Structural changes during ball-milling were followed by powder X-ray diffraction measurements, ...
    • Article  

      Structure inhomogeneities, shallow defects, and charge transport in the series of thermoelectric materials K2Bi8-xSb xSe13 

      Kyratsi, Theodora; Hatzikraniotis, E.; Paraskevopoulos, K. M.; Malliakas, C. D.; Dyck, J. S.; Uher, C.; Kanatzidis, M. G. (2006)
      The charge transport properties of the low-dimensional thermoelectric materials K2 Bi8-x Sbx Se13 (0<x≤8) were studied as a function of temperature and composition. The Seebeck coefficient shows an evolution from n - to p ...
    • Conference Object  

      Synthesis and thermoelectric properties of low-x Bi2Se 3-xS3 series 

      Iona, Ch; Hatzikraniotis, E.; Paraskevopoulos, K. M.; Kyratsi, Theodora (Affiliation: Department of Mechanical and Manufacturing Engineering, University of Cyprus, 1678, Nicosia, CyprusAffiliation: Department of Physics, Aristotle University of Thessaloniki, 54124, Thessaloniki, GreeceCorrespondence Address: Iona, Ch.Department of Mechanical and Manufacturing Engineering, University of Cyprus, 1678, Nicosia, Cyprus, 2010)
      Bi2Se3-xSx solid solutions, with low x values, were synthesized from melt. The solid solutions were studied in terms of phase purity using powder X-ray diffraction (PXRD) in order to find the maximum x value for the ...
    • Conference Object  

      Synthesis, crystal structure and thermoelectric properties of β-K 2Bi 8Se 13 solid solutions 

      Kyratsi, Theodora; Chung, D. Y.; Dyck, J. S.; Uher, C.; Lal, S.; Loo, S.; Hogan, T.; Ireland, J.; Kannewurf, C. R.; Hatzikraniotis, E.; Paraskevopoulos, K. M.; Kanatzidis, M. G. (Affiliation: Department of Chemistry, Michigan State University, East Lansing, MI 48824, United StatesAffiliation: Department of Physics, University of Michigan, Ann Arbor, MI 48109, United StatesAffiliation: Department of Electrical Engineering, Michigan State University, East Lansing, MI 48824, United StatesAffiliation: Department of Electrical Engineering, Northwestern University, Evanston, IL 60208, United StatesAffiliation: Department of Physics, Aristotle University of Thessaloniki, 54006 Thessaloniki, GreeceCorrespondence Address: Kyratsi, T.Department of Chemistry, Michigan State University, East Lansing, MI 48824, United States, 2003)
      Solid solution series of the type K 2Bi 8-xSb xSe 13, K 2-xRb xBi 8Se 13 as well as K 2B 18Se 13-xS x were prepared and the distribution of the atoms (Bi/Sb, K/Rb and Se/S) on different crystallographic sites, the band ...
    • Article  

      Synthetic conditions and their doping effect on β-K2Bi8Se13 

      Kyratsi, Theodora; Kika, I.; Hatzikraniotis, E.; Paraskevopoulos, K. M.; Chrissafis, K.; Kanatzidis, M. G. (2009)
      In this work the synthetic conditions for K2Bi8Se13 and their effect on its thermoelectric properties were investigated. K2Bi8Se13 was prepared as a single phase using K2Se and Bi2Se3 as starting materials in a furnace or ...
    • Conference Object  

      Thermal, electron transport and far infrared properties of PbTe single crystals doped with Br 

      Nikolic, M. V.; Paraskevopoulos, K. M.; Hatzikraniotis, E.; Nikolic, N.; Vujatovic, S. S.; Aleksic, O. S.; Zorba, T. T.; Kyratsi, Theodora; Menicanin, A.; Nikolic, P. M. (Affiliation: Institute for Multidisciplinary Research, Kneza Viseslava 1, 11000 Beograd, SerbiaAffiliation: Physics Department, Solid State Section, Aristotle University of Thessaloniki, 54214 Thessaloniki, GreeceAffiliation: Institute of Technical Sciences of SASA, Knez Mihailova 35, 11000 Beograd, SerbiaAffiliation: Department of Mechanical and Manufacturing Engineering, University of Cyprus, 1678 Nicosia, CyprusCorrespondence Address: Nikolic, M.V.Institute for Multidisciplinary Research, Kneza Viseslava 1, 11000 Beograd, Serbia, 2012)
      Understanding the properties of PbTe remains in focus as enhancement of thermoelectric efficiency of this material is studied extensively. In this work single crystals of PbTe, doped with less than 2 at % Br, were synthesized ...
    • Article  

      Thermoelectric properties of highly efficient Bi-doped Mg2Si1−x−ySnxGey materials 

      Khan, A. U.; Vlachos, N. V.; Hatzikraniotis, E.; Polymeris, G. S.; Lioutas, Ch B.; Stefanaki, E. C.; Paraskevopoulos, K. M.; Giapintzakis, John; Kyratsi, Theodora (2014)
      In this work, Bi-doped Mg2Si1−x−ySnxGey (x=0.4 and y=0.05) solid solutions with the nominal Bi content of 0⩽z⩽0.035 were synthesized by solid state synthesis and sintering via hot pressing, and were studied in terms of ...
    • Article  

      Thermoelectric properties of Mg2Si coatings deposited by pack cementation assisted process on heavily doped Si substrates 

      Stathokostopoulos, D.; Stefanaki, E. C.; Ioannou, M.; Polymeris, G. S.; Chaliampalias, D.; Pavlidou, E.; Kyratsi, Theodora; Paraskevopoulos, K. M.; Vourlias, G.; Hatzikraniotis, E. (2014)
      This work presents a study of structural and thermoelectric properties of Mg2Si coatings deposited on heavily doped p- and n-type Si substrates, at 650 C. The as-grown layers were smooth and uniform in thickness without ...
    • Article  

      Thermoelectric properties of nanocrystalline PbTe synthesized by mechanical alloying 

      Papageorgiou, Ch; Hatzikraniotis, E.; Lioutas, Ch B.; Frangis, N.; Valassiades, O.; Paraskevopoulos, K. M.; Kyratsi, Theodora (2010)
      In this work, nanocrystalline lead telluride powder was synthesized from high-purity elements by mechanical alloying by means of a planetary ball-milling procedure. The milling medium was tungsten carbide, and the diameter ...