- About Us
- Career Center
- Nano-Social Network
- Nano Consulting
- My Account
|Schematic of metal-lead sulfide quantum dot Schottky junction solar cells (glass/ITO/PbS QDs/LiF/Al). Novel Schottky junction solar cells developed at NRL are capable of achieving the highest open-circuit voltages ever reported for colloidal QD based solar cells.|
Photo: U.S. Naval Research Laboratory
U.S. Naval Research Laboratory (NRL) research scientists and engineers in the Electronics Science and Technology Division have demonstrated the highest recorded open-circuit voltages for quantum dot solar cells to date. Using colloidal lead sulfide (PbS) nanocrystal quantum dot (QD) substances, researchers achieved an open-circuit voltage (VOC) of 692 millivolts (mV) using the QD bandgap of a 1.4 electron volt (eV) in QD solar cell under one-sun illumination.
These results clearly demonstrate that there is a tremendous opportunity for improvement of open-circuit voltages greater than one volt by using smaller QDs in QD solar cells," said Woojun Yoon, Ph.D., NRC postdoctoral researcher, NRL Solid State Devices Branch. "Solution processability coupled with the potential for multiple exciton generation processes make nanocrystal quantum dots promising candidates for third generation low-cost and high-efficiency photovoltaics."
Despite this remarkable potential for high photocurrent generation, the achievable open-circuit voltage is fundamentally limited due to non-radiative recombination processes in QD solar cells. To overcome this boundary, NRL researchers have reengineered molecular passivation in metal-QD Schottky junction (unidirectional metal to semiconductor junction) solar cells capable of achieving the highest open-circuit voltages ever reported for colloidal QD based solar cells.
Experimental results demonstrate that by improving the passivation of the PbS QD surface through tailored annealing of QD and metal-QD interface using lithium fluoride (LiF) passivation with an optimized LiF thickness. This proves critical for reducing dark current densities by passivating localized traps in the PbS QD surface and metal-QD interface close to the junction, therefore minimizing non-radiative recombination processes in the cells.
Over the last decade, Department of Defense (DoD) analyses and the department's recent FY12 Strategic Sustainability Performance Plan, has cited the military's fossil fuel dependence as a strategic risk and identified renewable energy and energy efficiency investments as key mitigation measures. Research at NRL is committed to supporting the goals and mission of the DoD by providing basic and applied research toward mission-ready renewable and sustainable energy technologies that include hybrid fuels and fuel cells, photovoltaics, and carbon-neutral biological microorganisms.
About Naval Research Laboratory
The U.S. Naval Research Laboratory is the Navy's full-spectrum corporate laboratory, conducting a broadly based multidisciplinary program of scientific research and advanced technological development. The Laboratory, with a total complement of nearly 2,500 personnel, is located in southwest Washington, D.C., with other major sites at the Stennis Space Center, Miss., and Monterey, Calif. NRL has served the Navy and the nation for over 85 years and continues to meet the complex technological challenges of today's world. For more information, visit the NRL homepage or join the conversation on Twitter, Facebook, and YouTube.
For more information, please click here
Copyright © Naval Research LaboratoryIf you have a comment, please Contact us.
Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.
|Related News Press|
News and information
Scientists engineer tunable DNA for electronics applications June 21st, 2016
Marrying superconductors, lasers, and Bose-Einstein condensates: Chapman University Institute for Quantum Studies (IQS) member Yutaka Shikano, Ph.D., recently had research published in Scientific Reports June 20th, 2016
FEI and University of Liverpool Announce QEMSCAN Research Initiative: University of Liverpool will utilize FEIís QEMSCAN technology to gain a better insight into oil and gas reserves & potentially change the approach to evaluating them June 22nd, 2016
First single-enzyme method to produce quantum dots revealed: Biological manufacturing process, pioneered by three Lehigh University engineers, produces equivalent quantum dots to those made chemically--but in a much greener, cheaper way May 9th, 2016
Novel capping strategy improves stability of perovskite nanocrystals: Study addresses instability issues with organometal-halide perovskites, a promising class of materials for solar cells, LEDs, and other applications June 13th, 2016