May 21, 2013
Plasmonics ramp up nanocrystal photosensor performance
Reporting their results in the journal Nanotechnology, researchers have developed plasmonically coupled light-sensitive skins of nanocrystal monolayers that exhibit sensitivity enhancement and spectral range extension thanks to metallic nanostructures embedded in the photosensitive nanocrystal platform.
As the team from Bilkent University and Nanyang Technological University explains, plasmonic silver nanoparticles within the device increase the optical absorption of a CdTe nanocrystal monolayer. Controlled separation of these metallic nanoparticles in the vicinity of the semiconductor nanocrystals enables optimization of the photovoltage buildup in the device.
The enhancement factor was found to depend on the excitation wavelength. The scientists observed broadband sensitivity improvement (across 400–650 nm), with a 2.6-fold enhancement factor around the localized plasmon resonance peak.
The team’s findings have significant implications for the future design of photosensing platforms. These results could pave the way for the engineering of photosensitive NC-based devices such as smart transparent windows, light-sensitive walls and large-surface optical detection systems.
More information on this work can be found in the journal Nanotechnolgy.
About the author
Shahab Akhavan is a graduate student at UNAM-National Nanotechnology Research Center Bilkent University, Turkey. He is working on the fabrication of a new generation of light harvesting devices along with the scope of introducing new concepts into optoelectronic devices. Kivanc Gungor is a PhD student in the Department of Electrical and Electronics Engineering at Bilkent University. His research interests include the fabrication, characterization and simulation of plasmonic structures and their interaction with optically active materials. Dr Evren Mutlugun is a postdoctoral research fellow at Luminous! Centre of Excellence for Semiconductor Lighting and Displays, Nanyang Technological University, Singapore, and a visiting researcher in the Devices and Sensors Research Group at Bilkent University. He is working on exciton harvesting systems based on colloidal nanocrystal quantum dots for biosensing and optoelectronic applications. Prof. Hilmi Volkan Demir is a NRF fellow of Singapore and Nanyang Associate Professor and Director of Luminous! Centre of Excellence for Semiconductor Lighting and Displays at NTU. Concurrently, he is EURYI Associate Professor of Electrical Engineering, Physics, and UNAM-National Nanotechnology Research Center at Bilkent University. His research interests include nanocrystal optoelectronics, solid state lighting and energy applications.