Professor Keith Barnham’s Imperial College London based research team has pioneered the application of nanostructures such as quantum wells and quantum dots for solar photovoltaics.
The intellectual property generated through his research has resulted in a number of patents for the use of quantum wells in concentrator cells, the use of stress-balanced quantum wells in photovoltaic cells (SB-QWSC) and quantum dot light concentration (QDC).
Development work carried out over the years by Keith Barnham and his team has shown that the SB-QWPV cell has A) a wider bandgap than other GaAs PV cells, increasing the amount of power that can be generated, and B) can be grown dislocation free, improving efficiency and lifetime.
It is generally acknowledged within the PV academic community that the SB-QWPV is more efficient than other published cell types, and can be expected to add 3 or 4% to the efficiency of a multi-junction concentrator cell. In addition, the SB-QWPV cell is more flexible for varying to different wavelengths or spectra and can handle high temperatures, making it ideal for use under concentration.
The research group at Imperial have produced many single junction SB-QWSCs for analysis and testing. Wafer manufacture has been carried out at the EPSRC funded III-V Semiconductor Facilities at the University of Sheffield. Processing of the wafer to produce the PV cell has been carried out at a number of sub-contractors, most recently at the Centre for Integrated Photonics. Tests show that this single junction cell has an efficiency of 27%, close to the world record for a single-junction PV cell. At the 2006 World Photovoltaic conference in Hawaii, the inventor’s paper about the SB-QWSC, with efficiency enhanced by exploiting the unique feature of “photon-recycling,” was quoted in the conference highlights.
For more information, please review the paper Progress in quantum well solar cells or email us and request a copy of the paper.