NANO-MATERIALS FOR PHOTONIC APPLICATIONS
Department of Materials Science & Centre for Advanced Materials
Indian Association for the Cultivation of Science
Jadavpur, Kolkata 700032
The study of nanoscale matter-radiation interactions offers numerous opportunities for both fundamental research and technological applications in photonics and biophotonics. As these potential applications are still very much in the design-phase, the fundamental understanding the luminescence properties of rare-earth ions in oxide nano environments remains a challenge. From the fundamental point of view, the physical understanding of emission (up and down conversion) of rare-earth ions in oxide/semiconducting nanoparticles and the way it changes with size, crystal phase and concentration is very important [1-8]. The role of surface coating, doping and heating on the modification of crystal structure, local structure and their effect on the photoluminescence properties doped and coated nanocrystals will be discussed. Extended X-ray absorption fine structure measurements were carried out to understand the local environment of doped and coated nanocrystals. It is found that the local structure play most important role on the modifications of luminescence properties of doped and coated nanocrystals. Our analysis suggests that modifications of radiative and nonraditive relaxation mechanisms are due to local symmetry structure of the host lattice and crystal size, respectively. The energy transfer study from nanoparticles to dopant ions will be discussed.
 S. Saha, P.S. Chowdhury and A. Patra, “Luminescence of Ce3+ in Y2SiO5 nanocrystals: role of crystal structure and crystal size” J. Phys. Chem. B. 109, 2699- 2702 (2005).
 A. Patra, P. Ghosh, P. Saha Chowdhury, Márcio A. R. C. Alencar, W. Lozano B., N.Rakov, and G. S. Maciel, “Red to blue tunable upconversion in Tm3+ - doped ZrO2 nanocrystals” J. Phys. Chem. B. 109, 10142-10146 (2005).
 M. A. R. C. Alencar, G. S. Maciel and Cid B. de Araújo and A. Patra, “Er3+-doped BaTiO3 nanocrystals for nanothermometry: Influence of nanoenvironment on the sensitivity of a fluorescence based temperature sensor” Appl. Phys. Lett. 84, 4753- 4755 (2004).
 A. Patra, C. S. Friend, R. Kapoor and P. N. Prasad, “Effect of crystal nature on upconversion luminescence in Er3+:ZrO2 Nanocrystals” Appl. Phys. Lett. 83, 284- 286 (2003).
 G. S. Maciel and A. Patra, “Influence of nanoenvironment on luminescence lifetime of Er3+ activated ZrO2 nanocrystals” JOSA B. 21, 681-684 (2004).
 P. Ghosh, S. Sadhu and A. Patra “Preparation and photoluminescence properties of Y2SiO5: Eu3+ nanocrystals” Phys. Chem. Chem. Phys, 8, 3342-3348 (2006).
 P. Ghosh and A. Patra “Role of surface coating in ZrO2/Eu3+ nanocrystals” Langmuir, 22, 6321-6327(2006).
 P. S. Chowdhury and A. Patra, “Role of dopant concentration and surface coating on photophysical properties of CdS: Eu3+ nanocrystals” Phys. Chem. Chem. Phys, 8, 1329-1334 (2006).
 P. Ghosh, K. Priolkar and A. Patra, “Understanding the local structures of Eu and Zr in Eu2O3 doped and coated ZrO2 nanocrystals by EXAFS study” J. Phys. Chem. C, 111, 571-578 (2007).