Plasma-Sprayed Selective Emitters for Thermophotovoltaics

Plasma spraying has been shown to be an effective means of depositing thin films of various oxides for use as wavelength-selective emitters for thermophotovoltaic devices (see Figure 1). Wavelength-selective emitters are needed to increase the overall efficiencies of such devices. A suitable emitter material for a given thermophotovoltaic device is one that, when heated to incandescence, emits light with a spectral peak or peaks that preferably lie within the wavelength band of peak response of the photovoltaic cell in the device; more specifically, what is desired is low emissivity at photon energies less than the band gap and high emissivity at photon energies above the band gap of the photovoltaic cell.