High Efficiency Quantum Dot III-V Thermophotovoltaic Cell for Space Power

Quantum dots are nanoscale materials that have already improved the performance of optical sensors, lasers, light emitting diodes and solar cells. The unique properties of these nanomaterials offer tremendous benefit in developing high efficiency thermophotovoltaic cells as well. Theoretical studies predict a potential efficiency of 63.2% for an array of quantum dots sandwiched between the emitter and base layers in a typical photovoltaic junction. Significant gains can also be expected in the case of thermophotovoltaic cells. We propose an InGaAs TPV cell which incorporates InAs quantum dots to provide sub-gap absorption and thus improve the short-circuit current. This cell could then be integrated into a MIM to achieve a TPV cell whose efficiency would significantly exceed (by about 15% to 20%) current SOA standards. These TPV cells can be used for deep space missions, with a radioisotope thermoelectric generator (RTG) fueled by plutonium-238 as the on-board source of heat.