Thermochemistry, morphology, and optical characterization of germanium allotropes

Julia V. Zaikina, Elayaraja Muthuswamy, Kristina I. Lilova, Zachary M. Gibbs, Michael Zeilinger, G. Jeffrey Snyder, Thomas F. Fässler, Alexandra Navrotsky, Susan M. Kauzlarich

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

A thermochemical study of three germanium allotropes by differential scanning calorimetry (DSC) and oxidative high-temperature drop solution calorimetry with sodium molybdate as the solvent is described. Two allotropes, microcrystalline allo-Ge (m-allo-Ge) and 4H-Ge, have been prepared by topotactic deintercalation of Li7Ge12 with methanol (m-allo-Ge) and subsequent annealing at 250 °C (4H-Ge). Transition enthalpies determined by differential scanning calorimetry amount to 4.96(5) ± 0.59 kJ/mol (m-allo-Ge) and 1.46 ± 0.55 kJ/mol (4H-Ge). From high-temperature drop solution calorimetry, they are energetically less stable by 2.71 ± 2.79 kJ/mol (m-allo-Ge) and 5.76 ± 5.12 kJ/mol (4H-Ge) than α-Ge, which is the stable form of germanium under ambient conditions. These data are in agreement with DSC, as well as with the previous quantum chemical calculations. The morphology of the m-allo-Ge and 4H-Ge crystallites was investigated by a combination of scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. Even though the crystal structures of m-allo-Ge and 4H-Ge cannot be considered as truly layered, these phases retain the crystalline morphology of the layered precursor Li7Ge12. Investigation by diffuse reflectance infrared Fourier transform spectroscopy and UV-vis diffuse reflectance measurements reveal band gaps in agreement with quantum chemical calculations.

Original languageEnglish (US)
Pages (from-to)3263-3271
Number of pages9
JournalChemistry of Materials
Volume26
Issue number10
DOIs
StatePublished - May 27 2014

Fingerprint

Germanium
Thermochemistry
Differential scanning calorimetry
Calorimetry
Reflectometers
Crystallites
Fourier transform infrared spectroscopy
Methanol
Enthalpy
Atomic force microscopy
Energy gap
Crystal structure
Sodium
Annealing
Crystalline materials
Transmission electron microscopy
Temperature
Scanning electron microscopy

ASJC Scopus subject areas

  • Materials Chemistry
  • Chemical Engineering(all)
  • Chemistry(all)

Cite this

Zaikina, J. V., Muthuswamy, E., Lilova, K. I., Gibbs, Z. M., Zeilinger, M., Snyder, G. J., ... Kauzlarich, S. M. (2014). Thermochemistry, morphology, and optical characterization of germanium allotropes. Chemistry of Materials, 26(10), 3263-3271. https://doi.org/10.1021/cm5010467

Thermochemistry, morphology, and optical characterization of germanium allotropes. / Zaikina, Julia V.; Muthuswamy, Elayaraja; Lilova, Kristina I.; Gibbs, Zachary M.; Zeilinger, Michael; Snyder, G. Jeffrey; Fässler, Thomas F.; Navrotsky, Alexandra; Kauzlarich, Susan M.

In: Chemistry of Materials, Vol. 26, No. 10, 27.05.2014, p. 3263-3271.

Research output: Contribution to journalArticle

Zaikina, JV, Muthuswamy, E, Lilova, KI, Gibbs, ZM, Zeilinger, M, Snyder, GJ, Fässler, TF, Navrotsky, A & Kauzlarich, SM 2014, 'Thermochemistry, morphology, and optical characterization of germanium allotropes', Chemistry of Materials, vol. 26, no. 10, pp. 3263-3271. https://doi.org/10.1021/cm5010467
Zaikina JV, Muthuswamy E, Lilova KI, Gibbs ZM, Zeilinger M, Snyder GJ et al. Thermochemistry, morphology, and optical characterization of germanium allotropes. Chemistry of Materials. 2014 May 27;26(10):3263-3271. https://doi.org/10.1021/cm5010467
Zaikina, Julia V. ; Muthuswamy, Elayaraja ; Lilova, Kristina I. ; Gibbs, Zachary M. ; Zeilinger, Michael ; Snyder, G. Jeffrey ; Fässler, Thomas F. ; Navrotsky, Alexandra ; Kauzlarich, Susan M. / Thermochemistry, morphology, and optical characterization of germanium allotropes. In: Chemistry of Materials. 2014 ; Vol. 26, No. 10. pp. 3263-3271.
@article{3ed8afee1cd34c50b5235d38062c513d,
title = "Thermochemistry, morphology, and optical characterization of germanium allotropes",
abstract = "A thermochemical study of three germanium allotropes by differential scanning calorimetry (DSC) and oxidative high-temperature drop solution calorimetry with sodium molybdate as the solvent is described. Two allotropes, microcrystalline allo-Ge (m-allo-Ge) and 4H-Ge, have been prepared by topotactic deintercalation of Li7Ge12 with methanol (m-allo-Ge) and subsequent annealing at 250 °C (4H-Ge). Transition enthalpies determined by differential scanning calorimetry amount to 4.96(5) ± 0.59 kJ/mol (m-allo-Ge) and 1.46 ± 0.55 kJ/mol (4H-Ge). From high-temperature drop solution calorimetry, they are energetically less stable by 2.71 ± 2.79 kJ/mol (m-allo-Ge) and 5.76 ± 5.12 kJ/mol (4H-Ge) than α-Ge, which is the stable form of germanium under ambient conditions. These data are in agreement with DSC, as well as with the previous quantum chemical calculations. The morphology of the m-allo-Ge and 4H-Ge crystallites was investigated by a combination of scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. Even though the crystal structures of m-allo-Ge and 4H-Ge cannot be considered as truly layered, these phases retain the crystalline morphology of the layered precursor Li7Ge12. Investigation by diffuse reflectance infrared Fourier transform spectroscopy and UV-vis diffuse reflectance measurements reveal band gaps in agreement with quantum chemical calculations.",
author = "Zaikina, {Julia V.} and Elayaraja Muthuswamy and Lilova, {Kristina I.} and Gibbs, {Zachary M.} and Michael Zeilinger and Snyder, {G. Jeffrey} and F{\"a}ssler, {Thomas F.} and Alexandra Navrotsky and Kauzlarich, {Susan M.}",
year = "2014",
month = "5",
day = "27",
doi = "10.1021/cm5010467",
language = "English (US)",
volume = "26",
pages = "3263--3271",
journal = "Chemistry of Materials",
issn = "0897-4756",
publisher = "American Chemical Society",
number = "10",

}

TY - JOUR

T1 - Thermochemistry, morphology, and optical characterization of germanium allotropes

AU - Zaikina, Julia V.

AU - Muthuswamy, Elayaraja

AU - Lilova, Kristina I.

AU - Gibbs, Zachary M.

AU - Zeilinger, Michael

AU - Snyder, G. Jeffrey

AU - Fässler, Thomas F.

AU - Navrotsky, Alexandra

AU - Kauzlarich, Susan M.

PY - 2014/5/27

Y1 - 2014/5/27

N2 - A thermochemical study of three germanium allotropes by differential scanning calorimetry (DSC) and oxidative high-temperature drop solution calorimetry with sodium molybdate as the solvent is described. Two allotropes, microcrystalline allo-Ge (m-allo-Ge) and 4H-Ge, have been prepared by topotactic deintercalation of Li7Ge12 with methanol (m-allo-Ge) and subsequent annealing at 250 °C (4H-Ge). Transition enthalpies determined by differential scanning calorimetry amount to 4.96(5) ± 0.59 kJ/mol (m-allo-Ge) and 1.46 ± 0.55 kJ/mol (4H-Ge). From high-temperature drop solution calorimetry, they are energetically less stable by 2.71 ± 2.79 kJ/mol (m-allo-Ge) and 5.76 ± 5.12 kJ/mol (4H-Ge) than α-Ge, which is the stable form of germanium under ambient conditions. These data are in agreement with DSC, as well as with the previous quantum chemical calculations. The morphology of the m-allo-Ge and 4H-Ge crystallites was investigated by a combination of scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. Even though the crystal structures of m-allo-Ge and 4H-Ge cannot be considered as truly layered, these phases retain the crystalline morphology of the layered precursor Li7Ge12. Investigation by diffuse reflectance infrared Fourier transform spectroscopy and UV-vis diffuse reflectance measurements reveal band gaps in agreement with quantum chemical calculations.

AB - A thermochemical study of three germanium allotropes by differential scanning calorimetry (DSC) and oxidative high-temperature drop solution calorimetry with sodium molybdate as the solvent is described. Two allotropes, microcrystalline allo-Ge (m-allo-Ge) and 4H-Ge, have been prepared by topotactic deintercalation of Li7Ge12 with methanol (m-allo-Ge) and subsequent annealing at 250 °C (4H-Ge). Transition enthalpies determined by differential scanning calorimetry amount to 4.96(5) ± 0.59 kJ/mol (m-allo-Ge) and 1.46 ± 0.55 kJ/mol (4H-Ge). From high-temperature drop solution calorimetry, they are energetically less stable by 2.71 ± 2.79 kJ/mol (m-allo-Ge) and 5.76 ± 5.12 kJ/mol (4H-Ge) than α-Ge, which is the stable form of germanium under ambient conditions. These data are in agreement with DSC, as well as with the previous quantum chemical calculations. The morphology of the m-allo-Ge and 4H-Ge crystallites was investigated by a combination of scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. Even though the crystal structures of m-allo-Ge and 4H-Ge cannot be considered as truly layered, these phases retain the crystalline morphology of the layered precursor Li7Ge12. Investigation by diffuse reflectance infrared Fourier transform spectroscopy and UV-vis diffuse reflectance measurements reveal band gaps in agreement with quantum chemical calculations.

UR - http://www.scopus.com/inward/record.url?scp=84901447255&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84901447255&partnerID=8YFLogxK

U2 - 10.1021/cm5010467

DO - 10.1021/cm5010467

M3 - Article

AN - SCOPUS:84901447255

VL - 26

SP - 3263

EP - 3271

JO - Chemistry of Materials

JF - Chemistry of Materials

SN - 0897-4756

IS - 10

ER -