• Conference Object  

      Carrier mapping in thermoelectric materials 

      Polymeris, G. S.; Hatzikraniotis, E.; Stefanaki, E. C.; Pavlidou, E.; Kyratsi, Theodora; Paraskevopoulos, K. M.; Kanatzidis, M. G. (Affiliation: Physics Department, Aristotle University of Thessaloniki, GR- 54124, Thessaloniki, GreeceAffiliation: Department of Mechanical and Manufacturing Engineering, University of Cyprus, 1678 Nicosia, CyprusAffiliation: Department of Chemistry, Northwestern University, 2145 North Sheridan Road, Evanston, IL 60208, United StatesCorrespondence Address: Physics Department, Aristotle University of Thessaloniki, GR- 54124, Thessaloniki, Greece, 2013)
      The application of micro-fourier transform infrared (FT1R) mapping analysis to thermoelectric materials towards identification of doping inhomogeneities is described. Micro-FTIR, in conjunction with fitting, is used as ...
    • Article  

      Changes in the electronic properties of Bi2X3 (X: Se, Te) single crystals due to intercalation 

      Kyratsi, Theodora; Hatzikraniotis, E.; Paraskevopoulos, K. M.; Chrissafis, K. (1997)
      Bi2Se3 and Bi2Te3 are layered semiconductors n-type and p-type, respectively, which belong to the family of thermoelectric materials. In this work we examine the insertion of Cu in Bi 2Te3 and Bi2Se3 single crystals through ...
    • Article  

      Effect of antimony-doping and germanium on the highly efficient thermoelectric Si-rich-Mg2(Si,Sn,Ge) materials 

      Vlachos, N.; Polymeris, G. S.; Manoli, M.; Hatzikraniotis, E.; Khan, A. U.; Lioutas, C. B.; Stefanaki, E. C.; Pavlidou, E.; Paraskevopoulos, K. M.; Giapintzakis, John; Kyratsi, Theodora (2017)
      Two series of materials (a) Mg2Si0.55-ySn0.4Ge0.05Sby, 0 ≤ y ≤ 0.0175 and (b) Mg2Si0.5875-xSn0.4GexSb0.0125, 0 ≤ x ≤ 0.20 have been developed and studied in terms of structural features and thermoelectric properties/performance. ...
    • Article  

      Effect of Bi-doping and Mg-excess on the thermoelectric properties of Mg2Si materials 

      Ioannou, M.; Polymeris, G. S.; Hatzikraniotis, E.; Paraskevopoulos, K. M.; Kyratsi, Theodora (2014)
      In this work, Bi-doped magnesium silicide compounds were prepared by applying a combination of both, short-time ball milling and heating treatment. The effect of Mg excess was also studied, aiming towards further improvement ...
    • Article  

      The Effect of Ge on Mg2Si0.6−x Sn0.4Ge x Materials 

      Vlachos, N.; Hatzikraniotis, E.; Mihailescu, C. N.; Giapintzakis, John; Kyratsi, Theodora (2014)
      In this work, we investigate the influence of the introduction of Ge on the thermoelectric properties of Bi-doped quaternary Mg2Si0.6−x Sn0.4Ge x alloys. Mg2Si0.58−x Sn0.4Bi0.02Ge x materials were fabricated by a low ...
    • Article  

      Effect of sintering in ball-milled K 2Bi 8Se 13 thermoelectric nano-composites 

      Hatzikraniotis, E.; Ioannou, M.; Chrissafis, K.; Chung, D. Y.; Paraskevopoulos, K. M.; Kyratsi, Theodora (2012)
      K 2Bi 8Se 13 has many attractive features for thermoelectric applications. Recently, K 2Bi 8Se 13-based nanocomposite materials, consisting of nano-crystalline, micro-crystalline and amorphous phases, have been fabricated ...
    • Article  

      Efficiency study of a commercial thermoelectric power generator (TEG) under thermal cycling 

      Hatzikraniotis, E.; Zorbas, K. T.; Samaras, I.; Kyratsi, Theodora; Paraskevopoulos, K. M. (2010)
      Thermoelectric generators (TEGs) make use of the Seebeck effect in semiconductors for the direct conversion of heat to electrical energy. The possible use of a device consisting of numerous TEG modules for waste heat ...
    • Conference Object  

      Experimental and modeling evidence for the reduction of thermal conductivity in Mg2Si by fine tuning the nano & micro-structural features 

      Hatzikraniotis, E.; Polymeris, G. S.; Symeou, E.; Kyratsi, Theodora; Paraskevopoulos, K. M. (Elsevier Ltd, 2017)
      In this paper, experimental and modeling evidence for reduced thermal conductivity in Bi-doped Mg2Si is presented. Upon doping, lattice thermal conductivity was reduced monotonically and, at the same time, MgO content was ...
    • Article  

      Fabrication of nanocrystalline Mg 2Si via ball milling process: Structural studies 

      Ioannou, M.; Hatzikraniotis, E.; Lioutas, C.; Hassapis, T.; Altantzis, T.; Paraskevopoulos, K. M.; Kyratsi, Theodora (2012)
      In this work, nanocrystalline Mg 2Si material was fabricated via wet ball milling process using n-hexane as process control agent. Milling parameters, with emphasis on milling time and ball size, and conditions were studied ...
    • Conference Object  

      FTIR Reflectivity spectra of Thermoelectric K2Sb 8Se13 crystals 

      Hatzikraniotis, E.; Hassapis, Th; Kyratsi, Theodora; Paraskevopoulos, K. M.; Kanatzidis, M. G. (Affiliation: Physics Department, Aristotle University of Thessaloniki, 54124 Thessaloniki, GreeceAffiliation: Department of Mechanical and Manufacturing Engineering, University of CyprusAffiliation: Department of Chemistry, Michigan State University, MI 48824, United StatesCorrespondence Address: Hatzikraniotis, E.Physics Department, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece, 2006)
      Investigations of ternary and quaternary compounds, Bi and Sb chalcogenides, have shown that several multinary compounds containing alkali metals present promising thermoelectric properties. In this work, the FTIR reflectivity ...
    • Article  

      Inhomogeneities and Effective Mass in Doped Mg2Si 

      Stefanaki, E. C.; Polymeris, G. S.; Ioannou, M.; Pavlidou, E.; Hatzikraniotis, E.; Kyratsi, Theodora; Paraskevopoulos, K. M. (2016)
      Magnesium silicide (Mg2Si)-based materials are promising candidates as thermoelectric components for mid-temperature range (500–900 K) energy conversion. Many different approaches for determining the parabolicity of the ...
    • Conference Object  

      IR reflectivity studies of mechanically alloyed PbTe nanocrystals 

      Hasapis, T. Ch; Papageorgiou, C.; Hatzikraniotis, E.; Kyratsi, Theodora; Paraskevopoulos, K. M. (Affiliation: Department of Physics, Aristotle University of Thessaloniki, 54123 Thessaloniki, GreeceAffiliation: Department of Mechanical and Manufacturing Engineering, University of Cyprus, 1678 Nicosia, CyprusCorrespondence Address: Hasapis, T. Ch.Department of Physics, Aristotle University of Thessaloniki, 54123 Thessaloniki, Greece, 2009)
      Nano-crystalline lead telluride powder was synthesized by mechanical alloying using a high-energy planetary ball mill. The broadening of the X-ray diffraction peaks vs ball milling time, indicates small crystalline size ...
    • Article  

      Lattice thermal conductivity of K 2(Bi 1-zSb z) 8Se 13 solid solutions 

      Kyratsi, Theodora; Hatzikraniotis, E.; Paraskevopoulous, M.; Dyck, J. S.; Shin, H. K.; Uher, C.; Kanatzidis, M. G. (2004)
      The influence of the Bi/Sb partial substitution to the lattice thermal conductivity of the K 2(Bi 1-zSb z) 8Se 13 solid solution series was studied. The variation of the lattice thermal conductivity with comparison was ...
    • Conference Object  

      Long-term performance of a commercial thermoelectric power generator 

      Hatzikraniotis, E.; Zorbas, K.; Kyratsi, Theodora; Paraskevopoulos, K. M. (Affiliation: Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki, GreeceAffiliation: Department of Mechanical and Manufacturing Engineering, University of Cyprus, Nicosia, CyprusCorrespondence Address: Hatzikraniotis, E.Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece, 2009)
      In this work, thermoelectric device was made, using a commercially available ThermoElectric Generator (TEG), in order to measure the gained power and efficiency for long- term performance. The module was subjected to ...
    • Article  

      Macro and Micro-Scale Features of Thermoelectric PbTe (Br, Na) Systems: Micro-FTIR Spectroscopy, Micro-Seebeck Measurements, and SEM/EDX Observations 

      Stefanaki, E. C.; Polymeris, G. S.; Nikolic, P. M.; Papageorgiou, C.; Pavlidou, E.; Hatzikraniotis, E.; Kyratsi, Theodora; Paraskevopoulos, K. M. (2014)
      In this work, n-type and p-type PbTe doped with Br and Na, respectively, were thoroughly examined to determine the effect of the dopant on microstructure. Macro and micro homogeneity of the samples were studied by means ...
    • Book Chapter  

      Materials Science: Trends, material properties and educational perspectives 

      Hatzikraniotis, E.; Kyratsi, Theodora (Springer Netherlands, 2015)
      Materials Science is an interdisciplinary field involving the properties of matter and its applications to various areas of science and engineering. Materials Science investigates the relationships between the structure ...
    • Conference Object  

      Mechanical alloying synthesis of K2Bi8Se 13- type solid solutions 

      Toumpas, N.; Kyratsi, Theodora; Hatzikraniotis, E.; Tsiappos, A.; Pavlidou, E.; Paraskevopoulos, K. M.; Chung, D. Y.; Kanatzidis, M. G. (Affiliation: Department of Mechanical and Manufacturing Engineering, University of Cyprus, Nicosia, 1678, CyprusAffiliation: Department of Physics, Aristotle University of Thessaloniki, Thessaloniki, 54124, GreeceAffiliation: Materials Science Division, Argonne National Laboratory, Argonne, IL 60439, United StatesAffiliation: Department of Chemistry, Northwestern University, Evanston, IL 60208, United StatesCorrespondence Address: Toumpas, N.Department of Mechanical and Manufacturing Engineering, University of Cyprus, Nicosia, 1678, Cyprus, 2008)
      Solid solutions of β-K2Bi8-xSb xSe13 are an interesting series of materials for thermoelectric investigations due to their very low thermal conductivity and highly anisotropic electrical properties. In this work, we aimed ...
    • Conference Object  

      Modeling of thermal conductivity in high performing thermoelectric materials 

      Hatzikraniotis, E.; Kyratsi, Theodora; Paraskevopoulos, K. M. (Institute of Physics Publishing, 2017)
      The enhanced TE-performance in Mg2Si-Mg2Sn based pseudo-binaries is presented, which is attributed to low thermal conductivity. Sn-Si alloying, reduces the lattice thermal conductivity due to mass fluctuation. Furthermore, ...
    • Article  

      Modification of thermoelectric properties using insertion techniques 

      Hatzikraniotis, E.; Kyratsi, Theodora; Chrissafis, K.; Paraskevopoulos, K. M. (1999)
      In this work is presented the application insertion techniques for the modification of the performance of thermoelectric materials. The results indicate that in cases as in Bi2Se3 compounds where insertion of foreign species ...
    • Conference Object  

      N-to-p transition on K2Bi8-xSbxSe 13 series 

      Kyratsi, Theodora; Hatzikraniotis, E.; Tsiappos, A.; Paraskevopoulos, K. M.; Kanatzidis, M. G. (Affiliation: Department of Mechanical and Manufacturing Engineering, University of Cyprus, 1678 Nicosia, CyprusAffiliation: Department of Chemistry, Michigan State University, East Lansing, MI 48824, United StatesAffiliation: Department of Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki, GreeceCorrespondence Address: Kyratsi, Th.Department of Mechanical and Manufacturing Engineering, University of Cyprus, 1678 Nicosia, Cyprus, 2006)
      β-K2Bi8Se13 and its solid solutions have been found to be interesting for thermoelectric investigations mainly due to their low thermal conductivity and highly anisotropic electrical properties. Solid solution series of ...