synthesis of doped chromium oxide nanoparticles

  • View
    68

  • Download
    7

Embed Size (px)

Text of synthesis of doped chromium oxide nanoparticles

  1. 1. Credit seminar Size dependent optical properties of Zn doped Cr2O3 nanoparticles Submitted by: Name: Gaurav Kumar Yogesh Program: M.Sc. Physics (Nanophysics) Reg. No. CUPB/M.Sc./PMS/SBAS/2013-14/01 Supervisor: Dr. Kamlesh Yadav Centre for Physical and Mathematical Sciences 5/22/2015 1
  2. 2. Introduction Historic background Method to prepare nanoparticles Properties of nanoparticles Material and methods Experimental analysis Results and discussion Conclusions Review of literature References 5/22/2015 2
  3. 3. Technologies ,which incorporate the materials, to manipulate measures or features with atleast one of its critical dimensions between 1 nm to 100nm. Nanomaterials can be of two types; engineered or non-engineered Engineered nanoparticles are intentionally created to meet the specific applications e.g. CNT, Fullerene etc. Non-engineered nanoparticles are unintentionally created by nature such as volcanic ash, DNA and protein. 5/22/2015 3
  4. 4. www.essentialchemicalindustry.org 5/22/2015 4
  5. 5. Gold colloids were used for aesthetic (decoration) and curative purposes the Lycurgus Cup (4th Century B.C) is ruby red in transmitted light and green in reflected light, due to the presence of gold colloids 1857: Faraday reported formation of deep-red solutions of colloidal Au LS-FCM University di Bologna 5/22/2015 5
  6. 6. Fasters Lighters Can get into small spaces Cheaper More energy efficient Less waste product Use less materials to produce Different properties http://snf.stanford.edu/Education/Nanotechnologynt scales 5/22/2015 6
  7. 7. Top-Down approach These approach use larger (macroscopic) initial structure, which can be eternally controlled in the process of nanostructure. Typical examples are etching through the mask and ball milling and applications of several plastic deformation. Bottom-Up approach These approaches include the miniaturization of materials components (up to atomic level) with further self assembly process leading to the formation of nanostructure Typical examples are quantum dot formation during epitaxial growth and formation of nanoparticles from colloidal dispersion. 5/22/2015 7
  8. 8. Two of the reasons: 1. Ratio of surface area-to-volume of structure increases most atoms are at or near the surface, which make them more weakly bonded and more reactive. 2. Quantum mechanical effects are important, size of structure is on same scale as the wavelengths of electrons, and quantum confinement occurs resulting in changes in electronic and optical properties 5/22/2015 8
  9. 9. Supercomputer in your palm, Very tiny motors, pumps, micro sensor, and accelerometers; Energy storage (batteries) and conversion (solar cells) using nanowires and nanotubes Stain and wrinkle resistant clothes, transparent zinc oxide sunscreen, fast-absorbing drugs and nutrients. 5/22/2015 9
  10. 10. To synthesise the nanoparticles by using the novel solvent and cost effective To study the doping effect on its optical and structural properties. To compare the various results on its process of synthesising the nanoparticles and doping effects 5/22/2015 10
  11. 11. All the reagents were of AR/GR quality and were purchased from the Sigma-Aldrich, Loba- Chemi Pt. Ltd., and were used without further purification. Infrared (IR) spectra of nanoparticles were recorded with KBr on a Bruker FT-IR spectrometer. Surface morphology and size of the particles has been recorded with gold coating on the samples UV-visible spectroscopy was used to record the optical band of the nanoparticles. 5/22/2015 11
  12. 12. For the characterisation of the samples we do the following analysis 1. Morphological and structural analysis: FESEM had been used to study the morphological and structure of prepared samples. 2. Optical analysis: The optical band gap of the material had been calculated by the (Shimazdu 02206) UV-visible spectrometer 3. Spectroscopical analysis: The various functional groups and the characteristics peaks due to the various compounds can be observed by (Brucker Ltd) FTIR spectrometer All the experimental analysis has been performed at the lab of (Centre for Physical and Mathematical sciences) central university of Punjab, Bathinda 5/22/2015 12
  13. 13. http://www.iitk.ac.in/meesa/SEM/tutorial/SEM_MS 5/22/2015 13
  14. 14. FESEM image of the prepared samples of respective particle sizes are 55, 41, 26, 22 nm. Fig. FESEM image of Zn doped Cr2O3 nanoparticles 5/22/2015 14
  15. 15. FTIR stands for Fourier Transform Infrared Spectroscopy. Works on the principle of the Michelson's Interferometer. FTIR spectrometer acquires broadband NIR and FIR spectra. FTIR is method of obtaining the infrared spectra by collecting an inferogram of a sample signal, using the interferometer and then a Fourier transform on the inferogram to obtain the spectrum FTIR spectrometer collects and digitised the interferogram, perform the FT function and display the spectrum Every bond or the functional groups requires the different frequency for absorption, hence characteristic peaks is observed for the every functional groups or the part of the molecules. According to principle Applied Infrared frequency = Natural frequency of vibration 5/22/2015 15
  16. 16. Fig. FTIR characteristics peaks of the Zn doped Cr2O3 nanoparticles 5/22/2015 16
  17. 17. Fig. FTIR set-up of central university of Punjab, Bathinda 5/22/2015 17
  18. 18. Optical band gap of the following samples are calculated by Tauc relation, by extrapolating the slope of the peaks gives the optical band of the nanomaterials. Fig. Optical band of the samples are obtained by the FTIR data5/22/2015 18
  19. 19. Name of the samples Method of preparation of the samples Average particles size(nm) Optical band gap (eV) Characteristic peaks observed in FTIR (Cr-O Vibration) cm-1 Sample-1 Sol-gel 55 1.50 619 Sample-2 Sol-gel 26 3.50 484 Sample-3 Hydrothermal 22 3.70 760 Sample-4 Sol gel 41 2.09 803 5/22/2015 19
  20. 20. Decrease in the size of nanoparticles results in the increase in the optical band gap of the nanomaterials. It arises due the quantum confinement . Surface Plasmon resonance: The resonance condition is established when the frequency of incident photons matches the natural frequency of surface electrons oscillating against the restoring force of positive nuclei. SPR in subwavelength scale nanostructures can be polaritonic or plasmonic in nature. 5/22/2015 20
  21. 21. Fig. Variation of the particle size with Band gap of nanoparticles Fig. Variation of the refractive of the Nanoparticles with Band gap 5/22/2015 21
  22. 22. Size dependent optical properties of nanomaterials. Refractive index of the nanomaterials is decreases with the increases in the band gap. Confirmation of the quantum size effect. Cr2O3 nanoparticles can be used in creating the highly efficient solar cells and optoelectronic devices. Because of large band gap( 3 eV) used in the insulating materials. The band gap of the nanoparticles can altered by changing the environmental conditions or the preparing technique. It can used in manufacturing the Transparent conducting Oxide (TCO) materials which have both simultaneous property of conducting and transparent. 5/22/2015 22
  23. 23. Abdullah, M., Rajab, F. M., & Al-Abbas, S. M. (2014). Structural and optical characterization of Cr2O3 nanostructures: Evaluation of its dielectric properties. AIP Advances, 4(2), 027121. Athar, M., & Das, A. J. (2014). Therapeutic Nanoparticles: State-of-the-art of nanomedicine. Advanced Materials Review, 1(1), 25-37. Baobre-Lpez, M., Vzquez-Vzquez, C., Rivas, J., & Lpez-Quintela, M. A. (2003). Magnetic properties of chromium (III) oxide nanoparticles. Nanotechnology, 14(2), 318. Cao, H., Qiu, X., Liang, Y., Zhao, M., & Zhu, Q. (2006). Sol-gel synthesis and photoluminescence of p-type semiconductor Cr 2 O 3 nanowires. Applied physics letters, 88(24), 241112-241112-241113. Esparza, I., Paredes, M., Martinez, R., Gaona-Couto, A., Sanchez-Loredo, G., Flores- Velez, L. M., & Dominguez, O. (2011). Solid State reactions in Cr 2 O 3-ZnO nanoparticles synthesized by triethanolamine chemical precipitation. Materials Sciences and Applications, 2(11), 1584. Farzaneh, F. (2011). Synthesis and Characterization of Cr2O3 Nanoparticles with Triethanolamine in Water under Microwave Irradiation. Journal of Sciences, Islamic Republic of Iran, 22(4), 329-333. Fernandez-Garcia, M., Martinez-Arias, A., Hanson, J., & Rodriguez, J. (2004). Nanostructured oxides in chemistry: characterization and properties. Chemical Reviews, 104(9), 4063-4104.5/22/2015 23
  24. 24. Jaswal, V. S., Arora, A. K., Singh, J., Kinger, M., & Gupta, V. D. (2014). Synthesis and Characterization of Chromium Oxide Nanoparticles. Oriental Journal of Chemistry, 30(2), 559-566. Jin, H., Huang, Y., & Jian, J. (2015). Plate-like Cr 2 O 3 for highly selective sensing of nitric oxide. Sensors and Actuators B: Chemical, 206, 107-110. Kawabata, A., Yoshinaka, M., Hirota, K., & Yamaguchi, O. (1995). Hot Isostatic Pressing and Characterization of SolGelDerived Chromium (III) Oxide. Journal of the American Ceramic Society, 78(8), 2271-2273. Lei, S., Peng, X., Liang, Z., Li, X., Wang, C., Cheng, B., . . . Zhou, L. (2012). Self- template formation and properties study of Cr 2 O 3 nanoparticle tubes. Journal of Materials Chemistry, 22(4), 1643-1651. Li, D., Han, Z., Zheng, J., Wang, X., Geng, D., Li, J., & Zhang, Z. (2009). Spin canting and spin-flop transition in antiferromagnetic Cr 2 O 3 nanocrystals. Journal of Applied Physics, 106(5), 053913-053913-053915. Li, L., Yan, Z. F., Lu, G. Q., & Zhu, Z. H. (2006). Synthesis and structure characterization of chromium oxide prepared by solid thermal deco