Download
1 / 12
120 likes | 381 Vues
NSERC Engage Project Report. Improving light harvesting in 1-D TiO 2 nanostructures. The Shankar Research Group has prior expertise in growing TiO 2 nanotube and nanorod arrays. Shown below are Field Emission Scanning Electron Microscope (FESEM) images of TiO 2 nanorod arrays. .
E N D
NSERC Engage Project Report Improving light harvesting in 1-D TiO2 nanostructures The Shankar Research Group has prior expertise in growing TiO2 nanotube and nanorod arrays. Shown below are Field Emission Scanning Electron Microscope (FESEM) images of TiO2 nanorod arrays. Top-view of 100 nm wide TiO2 nanorod arrays Cross-section of TiO2 nanorod arrays
NSERC Engage Project: Motivation Underlying Motivation Improve light harvesting for photocatalysis and photovoltaics Objectives • Impregnate the walls and/or surfaces of TiO2nanorod/nanotube arrays with Cu, Ag and Au clusters • Perform optical simulations to determine the ideal nanotube array • architecture and the optimal distribution of metallic clusters in the architecture to maximize light harvesting. • Perform the detailed structural, morphological, chemical and optical • characterization of the fabricated plasmonic nanotube arrays.
NSERC Engage Project : Fabrication Optical Properties Gold nanoparticles + TiO2 nanorod arrays
NSERC Engage Project : Fabrication Gold nanoparticles were synthesized by techniques such as colloidal reduction and photochemical techniques
NSERC Engage Project: Fabrication TiO2 nanorod arrays coated with ~20 nm gold nanoparticles of medium separation Bare TiO2 nanorod arrays
NSERC Engage Project : Fabrication TiO2 nanorod arrays coated with closely spaced gold nanoparticles
NSERC Engage Project : Fabrication TiO2 nanorod arrays coated with widely spaced gold nanoparticles
NSERC Engage Project : Optical Properties Optical absorption vs optical wavelength of an aqueous suspension of gold nanoparticles. The peak at ~ 530 nm (green light) is characteristic of gold nanoparticles
NSERC Engage Project : Optical Properties Blue curve corresponds to the light absorption of bare nanorod arrays Green curve corresponds to the light absorption of nanorod arrays coated with gold nanoparticles. The small peak like feature at ~ 530 nm (green light) is characteristic of gold nanoparticles
NSERC Engage Project : Optical Properties A two-step process consisting of seeding gold nanoparticles followed by coarsening them was used to obtain improved over the size distribution and optical properties Yellow curve corresponds to the light absorption of bare nanorod arrays Red curve corresponds to the light absorption of nanorod arrays coated with seeds of gold nanoparticles. Green curve corresponds to the light absorption of nanorod arrays after coarsening of the seeded gold nanoparticles.
NSERC Engage Project : Simulations Large nanoparticles create more scattering instead of absorption : good for photovoltaics Small nanoparticles create more absorption than scattering : good for photocatalysis
NSERC Engage Project: Conclusion What is NOT new : a) Formation of gold nanoparticles b) Formation of TiO2 nanorod arrays What is New : • A process to fabricate TiO2nanorod arrays coated with a controlled distribution of gold nanoparticles. • Demonstration that light harvesting is improved by such a hybrid nanostructure • Simulations indicate that the control of nanoparticle placement within the nanostructure can be used to generate multiple peaks and enhanced light harvesting. The size distribution can be tailored to target photocatalysis or photovoltaic applications.
