Control of Carrier Concentration by Ag Doping in N-Type Bi2Te3 Based Compounds

Many elements have been used as dopants to enhance the thermoelectric performance of Bi2Te3-related materials. Among them, Ag’s effect on thermoelectric properties, where Ag acts as a donor or acceptor, remains unclear. To elucidate the role of Ag in n-type Bi2Te3 based compounds, Ag was added to n-type (Bi0.9Sb0.1)2(Te0.85Se0.15)3. As the amount of Ag was increased, the electron concentration decreased, which means Ag acted as an acceptor. The added Ag atoms were found to occupy interstitial sites in the hexagonal lattices, as confirmed by X-ray analysis and first principles calculations. The reduction in electron concentration was attributed to the interaction between the interstitial Ag and intrinsic defects.

[1]  D. Rowe.  CRC Handbook of Thermoelectrics , 1995 .

[2]  C. Liao,et al.  Thermoelectric Properties of Ag-Doped Bi2(Se,Te)3 Compounds: Dual Electronic Nature of Ag-Related Lattice Defects. , 2015, Inorganic chemistry.

[3]  L. Koudelka,et al.  Energy formation of antisite defects in doped Sb2Te3 and Bi2Te3 crystals , 1986 .

[4]  Y. Jeong,et al.  A hybrid method for the synthesis of small Bi0.5Sb1.5Te3 alloy particles , 2017 .

[5]  M. Dresselhaus,et al.  High-Thermoelectric Performance of Nanostructured Bismuth Antimony Telluride Bulk Alloys , 2008, Science.

[6]  G. Kresse,et al.  Ab initio molecular dynamics for liquid metals. , 1993 .

[7]  Shengbai Zhang,et al.  Native defects in second-generation topological insulators: Effect of spin-orbit interaction on Bi2Se3 , 2012 .

[8]  Y. Jeong,et al.  Method of Efficient Ag Doping for Fermi Level Tuning of Thermoelectric Bi0.5Sb1.5Te3 Alloys Using a Chemical Displacement Reaction , 2015 .

[9]  G. J. Snyder,et al.  Complex thermoelectric materials. , 2008, Nature materials.

[10]  B. Ryu,et al.  Computational Simulations of Thermoelectric Transport Properties , 2016 .

[11]  V. Kulbachinskii,et al.  Ferromagnetism in new diluted magnetic semiconductor Bi2−xFexTe3 , 2002 .

[12]  George S. Nolas,et al.  Thermoelectrics: Basic Principles and New Materials Developments , 2001 .

[13]  C. Elsässer,et al.  First-principles density functional theory study of native point defects in Bi2Te3 , 2011 .

[14]  J. Navrátil,et al.  Defect structure of Pb-doped Bi2Te3 single crystals , 2004 .

[15]  T. Lograsso,et al.  Native defects in tetradymite Bi2(TexSe3−x) topological insulators , 2013 .

[16]  Kyu Hyoung Lee,et al.  Design and preparation of high-performance bulk thermoelectric materials with defect structures , 2017 .

[17]  Hafner,et al.  Ab initio molecular-dynamics simulation of the liquid-metal-amorphous-semiconductor transition in germanium. , 1994, Physical review. B, Condensed matter.

[18]  Brian C. Sales,et al.  Smaller Is Cooler , 2002, Science.

[19]  Junyou Yang,et al.  Thermoelectric properties of silver-doped n-type Bi2Te3-based material prepared by mechanical alloying and subsequent hot pressing , 2006 .

[20]  Y. Jeong,et al.  Effect of hydrogen annealing of ball-milled Bi0.5Sb1.5Te3 powders on thermoelectric properties , 2017 .

[21]  M. Oh,et al.  Effect of ball milling time on the thermoelectric properties of p-type (Bi,Sb)2Te3 , 2013 .

[22]  Sung‐Jin Kim,et al.  Formation of Cu nanoparticles in layered Bi2Te3 and their effect on ZT enhancement , 2011 .

[23]  B. Cho,et al.  Post ionized defect engineering of the screen-printed Bi2Te2.7Se0.3 thick film for high performance flexible thermoelectric generator , 2017 .

[24]  J. Navrátil,et al.  Characterization of Ag-doped Sb1.5Bi0.5Te3 single crystals , 1998 .

[25]  J. Navrátil,et al.  Behavior of Ag Admixtures in Sb2Te3and Bi2Te3Single Crystals , 1998 .

[26]  A. Tkatchenko,et al.  Accurate molecular van der Waals interactions from ground-state electron density and free-atom reference data. , 2009, Physical review letters.

[27]  Burke,et al.  Generalized Gradient Approximation Made Simple. , 1996, Physical review letters.

[28]  M. Oh,et al.  Antisite defects in n-type Bi2(Te,Se)3: Experimental and theoretical studies , 2014 .

[29]  Brian H. Toby,et al.  EXPGUI, a graphical user interface for GSAS , 2001 .

[30]  Qian Zhang,et al.  Thermoelectric Property Studies on Cu‐Doped n‐type CuxBi2Te2.7Se0.3 Nanocomposites , 2011 .

[31]  H. W. Lee,et al.  Control of thermoelectric properties through the addition of Ag in the Bi0.5Sb1.5Te3Alloy , 2010 .

[32]  Beatriz Cordero,et al.  Covalent radii revisited. , 2008, Dalton transactions.