A highly efficient NiO-Doped MgO matched emitter for thermophotovoltaic energy conversion

A novel, thermally excited emitter material for thermophotovoltaic (TPV) energy conversion is described in this work. The new emitter is called a ‘matched emitter’ because its emissive power spectrum is matched very efficiently to the response of GaSb photovoltaic cells that convert the infrared radiation into electricity. It has been shown that doping concentrations of 2–4 wt.% Co3O4 or NiO within a low infrared emissivity MgO host will produce matched emitters with continuous, strong radiant emissions in the optimal energy range between 1 and 2 μm and minimal radiation at non-convertible wavelengths. The experimental measurements show that power densities of almost 9 W cm−2, in the convertible wavelength range between 1 and 1.9 μm, and temperatures of 1400°C or more are easily achieved with NiO-doped MgO tape cast emitters in an air–propane flame. The first reported emittance measurements for NiO-doped MgO tape cast emitters show that remarkably high peak emissivities, up to 0.9, at near optimal wavelengths for TPV energy conversion are achievable. Both the measured power density (9 W cm−2) and peak emissivity (nearly 0.9) appear to greatly exceed all previous values reported for any selective emitter at the given temperatures and wavelengths.