NASA SBIR 2005 Solicitation


SUBTOPIC TITLE:Deep Space Power Systems
PROPOSAL TITLE:Quantum Dot Spectrum Converters for Enhanced High Efficiency Photovoltaics

SMALL BUSINESS CONCERN (Firm Name, Mail Address, City/State/Zip, Phone)
DR Technologies, Inc
7740 Kenamar Court
San Diego ,CA 92121 - 2425
(858) 677 - 1226

PRINCIPAL INVESTIGATOR/PROJECT MANAGER (Name, E-mail, Mail Address, City/State/Zip, Phone)
Theodore G. Stern
7740 Kenamar Court
San Diego, CA  92121 -2425
(858) 677 - 1230

This research proposes to enhance solar cell efficiency, radiation resistance and affordability. The Quantum Dot Spectrum Converter (QDSC) disperses quantum dots into the transparent silicone layer that normally functions as coverglass adhesive. The Quantum Dots (QD) act as a fluorescent spectrum converter for solar cells, to allow the use of the 20-50% of the solar spectrum unavailable to today's highest efficiency solar cells. By selecting QD's of particular compositions and sizes, we customize absorption and emission spectra to down-convert UV photons, including multiple exciton generation, and up-convert IR photons in a multiple photon process. This approach overcomes the fundamental 'red-loss' and 'blue-loss' limitations, allowing more efficiency from conventional single- and multi-bandgap photovoltaic devices. We also explore the use of a QDSC in a non-tracking fluorescent concentrator for enhancing flux and shielding for solar cells and in thermophotovoltaic systems as a means of enhancing efficiency while eliminating selective emitters. These approaches address the topic need for significantly improved efficiency and radiation hardening for deep space missions ? the QDSC can significantly enhance conversion efficiency of qualified, high-efficiency cells, while its implementation in a luminescent or thermophotovoltaic concentrator allows solar cells to be shielded from adverse radiation and thermal environments.

The enhanced photovoltaic efficiency and spectrum management that will be provided by the Quantum Dot Spectrum Converter have broad application to NASA's missions. Many missions, including those for SEI, have high power requirements, and to avoid excessively large and high mass solar arrays there is a need for higher efficiency photovoltaics using qualified solar cells and near term enhancement technology. Spectrum management and enhanced shielding can be particularly applicable to planetary missions. For Mars missions, solar arrays are more useful if they can efficiently convert the large and changing red spectral component of diffused and filtered sunlight. The shielding approaches available with the Quantum Dot Luminescent Concentrator and the Quantum Dot Enhanced Thermophotovoltaics would assist in inner-planet missions, where thermal shielding is a significant problem, and outer planet missions, where trapped particulates play a significant role in radiation dosages. Improving the practicality of thermophotovoltaics and infra-red photovoltaic conversion also allows broader application of nuclear power and direct thermal conversion and storage

The potential to commercialize a Quantum Dot Luminescent Concentrator (QDLC) for residential and industrial use on earth will be large once the technology is proven to be both efficient and durable. Since the QDLC is a non-tracking plastic concentrator, it can be a very low cost, efficient sunlight collection means. The absorbed and re-emitted sunlight can be used in a commercial application for day-lighting purposes, or to power miniaturized, high efficiency solar cells. Either way, the high intensity "business end" of the QDLC is fed by a low cost, large area component. The economics of solar energy utilization becomes much more favorable if the large area collection components are made inexpensively; this is the fundamental idea behind concentrators, except that high-concentration ratio systems suffer from the need to accurately track the sun, forcing large apertures to be titled around on ungainly pointing and tracking systems. For commercial spacecraft, solar arrays with minimum area, mass and cost are needed for direct broadcast, cell phone and broadband spacecraft which have increasingly high power needs. The enhancements provided by the Quantum Dot Spectrum Converter (QDSC), and the QDLC could meet this critical need in the near-term and remain within the acceptable risk of new technologies adapted for commercial spacecraft use.

NASA's technology taxonomy has been developed by the SBIR-STTR program to disseminate awareness of proposed and awarded R/R&D in the agency. It is a listing of over 100 technologies, sorted into broad categories, of interest to NASA.

Optical & Photonic Materials
Photovoltaic Conversion
Semi-Conductors/Solid State Device Materials
Thermoelectric Conversion

Form Printed on 09-19-05 13:12