Towards a high-efficiency micro-thermophotovoltaic generator

Abstract

Hydrocarbon fuels have such a high energy density that even a relatively inefficient converter of chemical energy into electrical can significantly exceed the energy density of state- of-the-art batteries. This work attempts to do exactly this on a millimeter scale by means of thermophotovoltaic (TPV) power conversion approach. We demonstrated the first-of- a-kind propane-oxygen fueled catalytic silicon based MEMS microreactor integrated with low-bandgap GaInAsSb (0.53 eV bandgap) photovoltaic cells to create a fully operational millimeter scale TPV system. The initial fuel to electricity system efficiency was measured at 0.8%. A cell area of 2 cm2 produced 200 mW of electricity from a chemical input of 28 W. These results match well with developed system models. Additionally, we predict the efficiency can be doubled by improving the view factor, vacuum packaging, and eliminating parasitic radiation from the edges of the reactor. By integrating simple one-dimensional silicon/silicon dioxide photonic crystal on the micro-reactor as spectral shaping device efficiency can reach 5%.