Lead telluride

Lead telluride^[1][2][3]

Names
Other names Lead(II) telluride Altaite
Identifiers
CAS Number	1314-91-6 Y
ECHA InfoCard	100.013.862
PubChem CID	4389803
Properties
Chemical formula	PbTe
Molar mass	334.80 g/mol
Appearance	gray cubic crystals.
Density	8.164 g/cm3
Melting point	924 °C (1,695 °F; 1,197 K)
Solubility in water	insoluble
Band gap	0.25 eV (0 K) 0.32 eV (300 K)
Electron mobility	1600 cm2 V−1 s−1 (0 K) 6000 cm2 V−1 s−1 (300 K)
Structure
Crystal structure	Halite (cubic), cF8
Space group	Fm3m, No. 225
Lattice constant	a = 6.46 Angstroms
Coordination geometry	Octahedral (Pb2+) Octahedral (Te2−)
Thermochemistry
Std molar entropy (So298)	50.5 J·mol−1·K−1
Std enthalpy of formation (ΔfHo298)	-70.7 kJ·mol−1
Std enthalpy of combustion (ΔcHo298)	110.0 J·mol−1·K−1
Hazards
Safety data sheet	External MSDS
EU classification (DSD) (outdated)	Repr. Cat. 1/3 Harmful (Xn) Dangerous for the environment (N)
R-phrases (outdated)	R61, R20/22, R33, R62, R50/53
S-phrases (outdated)	S53, S45, S60, S61
Flash point	Non-flammable
Related compounds
Other anions	Lead(II) oxide Lead(II) sulfide Lead selenide
Other cations	Carbon monotelluride Silicon monotelluride Germanium telluride Tin telluride
Related compounds	Thallium telluride Bismuth telluride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)
Infobox references

Lead telluride is a compound of lead and tellurium (PbTe). It crystallizes in the NaCl crystal structure with Pb atoms occupying the cation and Te forming the anionic lattice. It is a narrow gap semiconductor with a band gap of 0.32 eV.^[4] It occurs naturally as the mineral altaite.

Contents

• 
  1 Properties
  


• 
  2 Applications
  


• 
  3 See also
  


• 
  4 References
  


• 
  5 External links
  

Properties

• 
  Dielectric constant ~1000.


• Electron Effective mass ~ 0.01m_e
  


• Hole mobility, μ_p = 600 cm² V⁻¹ s⁻¹ (0 K); 4000 cm² V⁻¹ s⁻¹ (300 K)

Applications

PbTe has proven to be a very important intermediate thermoelectric material. The performance of thermoelectric materials can be evaluated by the figure of merit, ZT=S2σT/κ{displaystyle ZT=S^{2}sigma T/kappa }, in which S{displaystyle S} is the Seebeck coefficient, σ{displaystyle sigma } is the electrical conductivity and κ{displaystyle kappa } is the thermal conductivity. In order to improve the thermoelectric performance of materials, the power factor (S2σ{displaystyle S^{2}sigma }) needs to be maximized and the thermal conductivity needs to be minimized.^[5]

The PbTe system can be optimized for power generation applications by improving the power factor via band engineering. It can be doped either n-type or p-type with appropriate dopants. Halogens are often used as n-type doping agents. PbCl2, PbBr2 and PbI2 are commonly used to produce donor centers. Other n-type doping agents such as Bi2Te3, TaTe2, MnTe2, will substitute for Pb and create uncharged vacant Pb-sites. These vacant sites are subsequently filled by atoms from the lead excess and the valence electrons of these vacant atoms will diffuse through crystal. Common p-type doping agents are Na2Te, K2Te and Ag2Te. They substitute for Te and create vacant uncharged Te sites. These sites are filled by Te atoms which are ionized to create additional positive holes.^[6] With band gap engineering, the maximum zT of PbTe has been reported to be 0.8 - 1.0 at ~650K.

Collaborations at Northwestern University boosted the zT of PbTe by significantly reducing its thermal conductivity using ‘all-scale hierarchical architecturing'.^[7] With this approach, point defects, nanoscale precipitates and mesoscale grain boundaries are introduced as effective scattering centers for phonons with different mean free paths, without affecting charge carrier transport. By applying this method, the record value for zT of PbTe that has been achieved in Na doped PbTe-SrTe system is approximately 2.2.^[8]

In addition, PbTe is also often alloyed with tin to make lead tin telluride, which is used as an infrared detector material.

See also

• 
  Yellow Duckling, which used a lead telluride sensor to make the first infrared linescan camera

References

1. 
   ^ Lide, David R. (1998), Handbook of Chemistry and Physics (87 ed.), Boca Raton, Florida: CRC Press, pp. 4–65, ISBN 978-0-8493-0594-8.mw-parser-output cite.citation{font-style:inherit}.mw-parser-output .citation q{quotes:"""""""'""'"}.mw-parser-output .citation .cs1-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .citation .cs1-lock-limited a,.mw-parser-output .citation .cs1-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .citation .cs1-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/4/4c/Wikisource-logo.svg/12px-Wikisource-logo.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{font-size:100%}.mw-parser-output .cs1-maint{display:none;color:#33aa33;margin-left:0.3em}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}
   


2. 
   ^ CRC Handbook, pp. 5–24.
   


3. 
   ^ Lawson, William D (1951). "A method of growing single crystals of lead telluride and selenide". J. Appl. Phys. 22 (12): 1444–1447. doi:10.1063/1.1699890.
   


4. 
   ^ Kanatzidis, Mercouri G. (2009-10-07). "Nanostructured Thermoelectrics: The New Paradigm? †". Chemistry of Materials. 22 (3): 648–659. doi:10.1021/cm902195j.
   


5. 
   ^ He, Jiaqing; Kanatzidis, Mercouri G.; Dravid, Vinayak P. (2013-05-01). "High performance bulk thermoelectrics via a panoscopic approach". Materials Today. 16 (5): 166–176. doi:10.1016/j.mattod.2013.05.004.
   


6. 
   ^ Dughaish, Z. H. (2002-09-01). "Lead telluride as a thermoelectric material for thermoelectric power generation". Physica B: Condensed Matter. 322 (1–2): 205–223. doi:10.1016/S0921-4526(02)01187-0.
   


7. 
   ^ Biswas, Kanishka; He, Jiaqing; Zhang, Qichun; Wang, Guoyu; Uher, Ctirad; Dravid, Vinayak P.; Kanatzidis, Mercouri G. (2011-02-01). "Strained endotaxial nanostructures with high thermoelectric figure of merit". Nature Chemistry. 3 (2): 160–166. doi:10.1038/nchem.955. ISSN 1755-4330. PMID 21258390.
   


8. 
   ^ Biswas, Kanishka; He, Jiaqing; Blum, Ivan D.; Wu, Chun-I.; Hogan, Timothy P.; Seidman, David N.; Dravid, Vinayak P.; Kanatzidis, Mercouri G. (2012-09-20). "High-performance bulk thermoelectrics with all-scale hierarchical architectures". Nature. 489 (7416): 414–418. doi:10.1038/nature11439. ISSN 0028-0836. PMID 22996556.
   

External links

• National Pollutant Inventory Lead and compounds fact sheet


• Webelements

v t e Lead compounds
Pb(II)	PbBr2 Pb(C5H5)2 Pb(C2H3O2)2 PbCl2 PbCO3 PbCrO4 PbF2 PbHAsO4 PbI2 Pb(NO3)2 Pb(N3)2 PbO Pb(OH)2 Pb3(PO4)2 PbS Pb(SCN)2 PbSe PbSO4 PbTe PbTiO3 plumbite PbC2 (hypothetical)
Pb(II,IV)	Pb3O4
Pb(IV)	Pb(C2H3O2)4 PbCl4 PbF4 PbH4 PbO2 PbS2 plumbate Pb(OH)4 (hypothetical)

v t e Tellurides

H2Te He Li2Te BeTe B CTe2 (CH3)2Te (NH4)2Te O F Ne Na2Te MgTe Al Si P2Te5 S Cl Ar K2Te CaTe Sc2Te3 Ti V Cr MnTe MnTe2 FeTe CoTe NiTe CuTe ZnTe GaTe Ga2Te3 GeTe As2Te3 As4Te3 Se Br Kr Rb2Te SrTe Y2Te3 Zr Nb MoTe2 Tc Ru Rh Pd Ag2Te CdTe In2Te3 SnTe SnTe2 Sb2Te3 Te I Xe Cs2Te BaTe * Hf TaTe2 WTe2 WTe3 ReTe2 Os Ir Pt AuxTey HgTe Tl2Te PbTe Bi2Te3 Po At Rn Fr Ra ** Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og ↓ * La2Te3 Ce2Te3 Pr2Te3 Nd2Te3 Pm Sm2Te3 Eu2Te3 Gd Tb Dy Ho Er2Te3 Tm2Te3 Yb Lu ** Ac ThTe2 Pa UTe2 Np Pu Am Cm Bk Cf Es Fm Md No Lr

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