Phase Transformations and Thermal Stability of CdSe Quantum Dots: Cubic to Hexagonal

  • M. Verma
  • D. Patidar
  • K. B. Sharma
  • N. S. Saxena


CdSe quantum dots (QDs) having size 3–5 nm have been synthesized by chemical co-precipitation method in mixed amorphous and cubic phase. These QDs have been characterized by using X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM) and Fourier transform infrared (FTIR) spectrometry. Cubic phase is confirmed by XRD and amorphous phase have been found using differential scanning calorimetry (DSC). The thermal analysis carried out by using DSC at different heating rates shows endothermic and exothermic peaks at different temperatures corresponding to their glass transition and different crystalline phases. The cubic phase of the crystalline CdSe obtained at 261 °C in the DSC scan of as prepared sample start transforming to stable hexagonal phase of CdSe corresponding to second crystallization peak 317 °C in DSC thermogram. Differential thermal analysis (DTA) and thermogravimetric analysis (TGA) have also been used to determine the crystallization temperature (257 °C) and weight loss in the temperature range 220–267 °C. Activation energies corresponding to two exothermic peaks (cubic and hexagonal phase) have been determined by employing different theoretical models. Lower activation energy of the hexagonal phase corresponding to second exothermic peak obtained at higher temperature in the DSC thermogram shows the higher thermal stability of this phase and could be employed for preparing a material to improve the performance of memory devices, solar cells etc.


X-ray diffraction TEM Calorimetry TGA 



Authors gratefully acknowledge the financial grant received from UGC, New Delhi (India) in the form of Emeritus Fellowship to Prof. N.S. Saxena and BSR fellowship (JRF) to Mr. M. Verma.


  1. 1.
    Y. Wu, C. Wadia, W. Ma, B. Sadtler, A.P. Alivisatos, Nano Lett. 8, 2551–2555 (2008)CrossRefGoogle Scholar
  2. 2.
    I. Gur, N.A. Fromer, M.L. Geier, A.P. Alivisatos, Science 310, 462–465 (2005)CrossRefGoogle Scholar
  3. 3.
    R. Gangadharan, V. Jayalakshmi, J. Kalaiselvi, S. Mohan, R. Murugan, B. Palanivel, J. Alloys Comp. 359, 22–26 (2003)CrossRefGoogle Scholar
  4. 4.
    A. Kanti, P. Kumbhakar, Res. Phys. 2, 150–155 (2012)Google Scholar
  5. 5.
    N.A. Hosiny, A. Badawai, M.A.A. Moussa, R.E. Agmy, S. Abdallah, Int. J. Nanoparticles. 5, 258–266 (2012)CrossRefGoogle Scholar
  6. 6.
    S.R. Dhage, H.A. Colorado, H.T. Hahn, Mater. Res. 16, 504–507 (2013)CrossRefGoogle Scholar
  7. 7.
    G.A.D. Silva, D.M. Triches, E.A. Sanches, K.D. Machado, C.M. Poffo, J.C.D. Lima, S.M.D. Souza, J. Mole. Struct. 1074, 511–515 (2014)CrossRefGoogle Scholar
  8. 8.
    R.J. Bandaranayake, G.W. Wen, J.Y. Lin, H.X. Jiang, C.M. Sorensen, Appl. Phys. Lett. 67, 831–833 (1995)CrossRefGoogle Scholar
  9. 9.
    H.E. Kissinger, Anal. Chem. 29, 1702–1706 (1957)CrossRefGoogle Scholar
  10. 10.
    J.A. Augis, J.E. Bennett, J. Therm. Anal. Calor. 13, 283–292 (1978)CrossRefGoogle Scholar
  11. 11.
    T. Ozawa, Polymer 12, 150–158 (1971)CrossRefGoogle Scholar
  12. 12.
    M. Verma, D. Patidar, K.B. Sharma, N.S. Saxena, J. Nanoelectron. Optoelectron. 10, 320–326 (2015)CrossRefGoogle Scholar
  13. 13.
    M.F. Kotkata, A.E. Masoud, M.B. Mohamed, M.A. Mahmoud, Physica E 41, 640–645 (2009)CrossRefGoogle Scholar
  14. 14.
    T.S. Shyju, S. Anandhi, R. Indirajith, R. Gopalakrishnan, J. Crys. Growth. 337, 38–45 (2011)CrossRefGoogle Scholar
  15. 15.
    M. Avarmi, J. Chem. Phys. 7, 1103–1112 (1939)CrossRefGoogle Scholar
  16. 16.
    M. Avarmi, J. Chem. Phys. 8, 12–224 (1940)Google Scholar

Copyright information

© Springer Science+Business Media New York 2015

Authors and Affiliations

  • M. Verma
    • 1
  • D. Patidar
    • 1
  • K. B. Sharma
    • 1
  • N. S. Saxena
    • 1
  1. 1.Lab. No. 14–15, Semiconductor and Polymer Science Laboratory, Department of PhysicsUniversity of RajasthanJaipurIndia

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