CASE STUDIES ON COMBUSTION SYNTHESIS OF CHALCOGENIDES

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CASE STUDIES ON COMBUSTION SYNTHESIS OF
CHALCOGENIDES

• S. Sundar Manoharan
• Department of Chemistry
• INDIAN INSTITUTE OF TECHNOLOGY KANPUR

SHS meeting at IISc November 28,2008
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• A bit on the history of wet combustion
• route
• Some catch words at Prof. KCPs lab
• High energy solids
• Hydrazine and Hydrazide based complexes
• Hydrazine carboxylate solid solution precursors
• Autocatalytic combustion

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1987 December
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1989
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• SOME ISSUES CONCERNING COMBUSTION PROCESS
• Stoichiometry
• Non oxide ceramics
• Scale up proces

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• CdS, ZnS, ZnO are the wide band gap II-VI
  semiconductor materials having band gap value
• CdS Eg 2.4eV
• ZnS Eg 3.6eV
• ZnO Eg 3.3eV
• Offer a huge potential in wide range of
  applications e.g. LEDs, solar cells, UV lasers,
  sensors, bio-medical applications etc.
• Enormous potential lie in the possibility of
  band gap modulations and tuning of electrical and
  optical properties by
• quantum confinement
• alloying with other semiconductors of same
  class
• by doping transition metal ions

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Studies on Ag2Se Studies on CdS
Comparison with sonochemical synthesis
Studies on CdS-ZnS Solid solutions Tuning the
band gap Studies on ZnOMn Selective
substitution
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Comparative study of CdS prepared by (a)
sonochemical and (b) microwave routes
(a)
(b)
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Comparative study of CdS prepared by (a)
sonochemical and (b) microwave routes
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Cd1-xZnxS solid solutions prepared by microwave
route
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Cd1-xZnxS solid solutions prepared by microwave
route
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Cd1-xZnxS solid solutions prepared by microwave
route
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2.33 - 2.12eV (530-590 nm)
Schematic diagram showing possible transition
involved in the emission features of CdZnMnS
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Transition metal ion doping doping of Mn2
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Mn doped CdZnS
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Absorbance spectra of CdZnMnS
EPR spectra of CdZnMnS
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PL spectra of CdZnMnS (Inset shows PL for CdS and
ZnS)
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PL spectra of CdZnMnS (Zn excess case)
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Study on the origin of ferromagnetism in Mn
doped ZnO
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For understanding complex mechanisms
underlying electronic and magnetic properties
of Inorganic oxides and sulphides , combustion
synthesis serves as a best Synthetic tool