A three-year grant worth of approximately $1 million will be shared by the scientists at the University of Arkansas and Arkansas State University to study the utility of semiconductor and metallic nanoparticles in solar cells that are used as power sources in satellites and spacecrafts.
When ultraviolet light is applied to nanocrystals in the vials on the left, the size of the nanocrystals change and emit different, more colorful light. These nanocrystals are investigated for their use in high performance solar cells.
Omar Manasreh, principal investigator and electrical engineering professor at the University of Arkansas, will secure a total fund of $710,646, which includes cost-sharing funds of $236,882 from the University of Arkansas and $473,764 from NASA. Liangmin Zhang, who serves as an Assistant Professor at Arkansas State University, will secure $85,617 from Arkansas State University and $171,235 from NASA. In 2010, the U.S. Air Force Office of Scientific Research awarded a five-year grant worth $1.13 million, which included the University of Arkansas’ cost sharing funds, to Manasreh for a similar type of work.
The research on the development of semiconductor and metallic nanoparticles at the Optoelectronics Research Lab of Manasreh can pave the way to the inception of a private firm in Arkansas. The major objective of the work is to produce and demonstrate a solar cell that can have a conversion efficiency of 40% or more. It is not possible to obtain light-to-energy conversion efficiency more than 23% with the silicon-based solar panels presently used on spacecraft and NASA satellites.
Manasreh uses two methods to produce solar cells. In the first method, a combination of copper, indium, gallium and selenium (CuInGaSe2 and CuInSe2) is utilized as the semiconductor material in place of silicon to grow nanocrystals. Functioning of the nanocrystals is made possible by generation of volatile ligands that are molecules bonded to a central atom. The nanocrystals are then either coupled with zinc oxide or titanium dioxide nanotubes or modified into thin films to fabricate the required solar cells, whose performance is subsequently tested and assessed by the researchers.
The second method employs molecular beam epitaxy, a process of nanocrystal deposition, to fabricate quantum dots made of indium arsenide (InAs). Quantum dots are nanoscale semiconductor materials. In order to improve the solar cell performance, short ligands will be used by the researchers to combine metallic nanoparticles to the quantum dots and nanocrystals. The researchers will then study trapping sun light’s plasmonic effect, which in turn improves the conversion efficiency of the cells. A plasmon is a quantum of charge waves produced by light.