High Efficiency InAsSb / AlAsSb Quantum Dot Solar Cells

ABSTRACT: Magnolia Solar proposes to develop an innovative high-efficiency, single-junction solar cell in collaboration with Prof. Diana Huffaker and her group by utilizing multi-photon absorption processes in InAsSb/AlAsSb quantum dot structures. The proposed device structure satisfies the unique qualities required by intermediate band solar cell theory to achieve ultra-high conversion efficiency. This system has a potential to achieve efficiencies over 50% under concentrated light conditions. The proposed structure has the optimum band alignment and bandgap combination for quantum dot and barrier materials in a quantum dot solar cell. InAsSb quantum dots in AlAsSb barriers form a type II band alignment, which has long carrier life times that enable high carrier extraction efficiencies. During the Phase I STTR effort, we synthesized InAsSb dots with excellent structural and optical properties and demonstrated the technical feasibility of InAsSb quantum dot solar cells. Phase II efforts will focus on demonstrating and optimizing multi-photon solar cells, leveraging our team"s broad experience in band gap engineering, simulation, light trapping, and device design. BENEFIT: Photovoltaic (PV) devices can provide a mobile source of electrical power for a variety of military applications in both space and terrestrial environments. Many of these mobile power applications can directly benefit from enhancements in the efficiency of the photovoltaic devices. The terrestrial, defense, and spacecraft power photovoltaic markets provide a significant commercial opportunity for the technology developed during this STTR effort. The worldwide PV market generates over $4.5 billion (US) per year in revenue and has been growing at over 30% annually since the late 1990s. Space-based PV systems will utilize technologies that improve radiation hardness, operating temperature range, efficiency, and specific power. Our technology development and commercialization strategy involves several distinct steps. Magnolia has detailed the tremendous long term benefits of increasing the efficiency of solar cells for terrestrial applications. In addition use of the micro-concentrators also provides a means of inserting quantum dot-based solar cells with innovative nanostructured coatings into the renewable energy market.