Advanced Epitaxial Lift-Off Quantum Dot Photovoltaic Devices

Period of Performance: 01/01/2012 - 12/31/2012

$125K

Phase 1 STTR

Recipient Firm

Microlink Devices
6457 West Howard Street
Niles, IL 60714
Firm POC
Principal Investigator

Research Institution

Rochester Institute of Technology
One Lomb Memorial Drive
Rochester, NY 14623
Institution POC

Abstract

We propose to develop a high-efficiency, triple-junction, epitaxial lift-off (ELO) solar cell by incorporating quantum dots (QDs) within the current-limiting subcell. We intend to leverage existing QD epitaxy processes developed by the Rochester Institute of Technology and combine this with MicroLink's expertise in multi-junction cell growth and ELO technology. We will employ QDs to enhance the middle cell absorption in a InGaP/GaAs/InGaAs metamorphic IMM cell. Detailed balance calculations indicate that the triple junction efficiency can be increased to ~42% by reducing the bandgap of the middle cell to ~1.2 eV. The combination of the QD technology with multi-junction ELO technology will be exploited in two ways: i) ELO GaAs cells with QD can be grown into full triple-junction cells and ii) back-surface reflectors on the ELO cells will be used to improve absorption by routing IR light for a second pass through the QD subcell. The relevance of this work to NASA is that it will result in lightweight, high-efficiency, triple-junction solar cells that will have a specific power>500 W/kg. In addition, the use of QDs has been shown to improve radiation tolerance of the photovoltaic device.