International congress on innovative advances in science, technology and engineering - Dubai - United-Arab-Emirates (2020-03-05)

Lanthanide based hybrid nanostructures: Multicolour luminescence, energy transfer and multifunctional applications
We have synthesized a rare-earth based novel inorganic-organic hybrid nanostructure (IOHN) composed of fluoride nanophosphors and β-diketones coordination compounds.[1-5] The fluoride nanophosphors separately give intense emission in visible region under near infrared (NIR) excitation, known as upconversion (UC) emission, while β-diketones coordination compounds again give intense emission upon ultra-violet (UV) excitation, known as downshifting emission.[5-10] The IOHN, therefore, gives intense emission upon both UV and NIR excitation sources. The XRD and FTIR measurements reveal both the systems are not bonded with each-other, rather entangled with weak interacting forces. The TEM analyses reveal that, the prepared ultrafine upconversion nanoparticles are dispersed on the surface of coordination compounds. The IOHN comprises excellent dual-mode optical features (DS and UC) of both the phases. Energy transfer from Er3+/Ho3+ (doped in inorganic phase) to Eu3+/Tb3+ (coordinated in organic phase) demonstrates for a viable coupling between both the phases. Because of ultrafine particle size the surface to volume ratio is relatively higher which improves the attachment of particles with the fingermarks. To further enhance the dual mode emission of IOHN, Silver nanoparticles (AgNPs) have been introduced. The emission intensity of UC as well as DS emission has been found to be strongly modulated in the presence of AgNPs. It has been found that AgNPs enhances UC emission. The possible mechanism involved in enhanced emission intensity and color output has been investigated in details. The excellent optical properties of these nano-hybrid materials provide a great opportunity in the field of ultraviolet (UV) sensing and energy devices.[11-14] 1. M. P. Saradhi and U. V. Varadaraju, Chem. Mater., 2006, 18, 5267-5272. 2. J. C. G. Bunzli, Chem. Rev., 2010, 110, 2729-2755. 3. M. Nyk, R. Kumar, T. Y. Ohulchanskyy, E. J. Bergey, and P. N. Prasad, Nano Lett., 2008, 8 (11), 3834-3838. 4. D. Timmerman, I. Izeddin, P. Stallinga, I. N. Yassievich and T. Gregorkiewicz, Nature Photonics, 2008, 2, 105-109. 5. X. Chen, W. Xu, H. Song, C. Chen, H. Xia, Y. Zhu, D. Zhou, S. Cui, Q. Dai, and J. Zhang, ACS Appl. Mater. Interfaces, 2016, 8, 9071-9079. 6. S. F. H. Correia, V. D. Z. Bermudez, S. J. L. Ribeiro, P. S. Andre, R. A. S. Ferreira and L. D. Carlos, J. Mater. Chem. A, 2014, 2, 5580-5596. 7. Z. Fan, K. Sunc and J. Wang, J. Mater. Chem. A, 2015, 3, 18809-18828. 8. X. Huang, S. Han, W. Huang and X. Liu, Chem. Soc. Rev., 2013, 42, 173-201. 9. P. K. Shahi, A. K. Singh, S. B. Rai and B. Ullrich, Sens. Actuators A, 2015, 222 255-261. 10. P. Singh, P. K. Shahi, S. K. Singh, A. K. Singh, M. K. Singh, R. Prakash and S. B. Rai Nanoscale, 2017 9 696-705. 11. P. K. Shahi, A. K. Singh, S. K. Singh, S. B. Rai and B. Ullrich, ACS Appl. Mater. Interfaces, 2015, 7, 18231-18239. 12. P. K. Shahi, P. Singh and S. B. Rai, J. Phys. D: Appl. Phys., 2017, 50 075501(7pp). 13. P. K. Shahi, P. Singh, A. K. Singh, S. K. Singh, S. B. Rai and R. Prakash, J. Colloid Interface Sci., 2017, 491, 199-206. 14. P. Singh, P. K. Shahi, R. Prakash and S. B. Rai, Nanotechnology 28 (41), 415701
Assist. Prof. Dr. Praveen Kumar Shahi