Progress in thermophotovoltaic converters

Transparent conducting oxides as selective filters in thermophotovoltaic devices

“…The maximum of Q corresponds to an optimal electron concentration (N = 8.7×10 20 cm −3 ) for the TCO used like a selective filter in the silicon based TPV devices. This value fits quite well with experimental ones, 7 × 10 20 cm −3 , reported for SnO 2 :F used like a selective filter [4]. However, in that work, the authors found that the efficiency of the system using SnO 2 :F like a selective filter was lower (2.1%) than the efficiency using the quartz filter (2.4%).…”

“…Of these, the doping method is the most commonly used. In literature the growth of several TCO thin film systems has been reported [4,[6][7][8][9][10][11][14][15][16]. Electron concentration values reported for these TCO thin films are in the range 7×10 19 -7.5×10 21 cm −3 .…”

“…SnO 2 :F, with an electron concentration of 7 × 10 20 cm −3 , an electron mobility of 17.8 cm 2 V −1 s −1 , a layer thickness of 468 nm and a transmittance of 76% at the maximum emitter (Yb 2 O 3 ) radiation, has been recently reported as a selective filter in a Si based TPV system, exhibiting an electricity-to-gas (heat source) power efficiency of 2.1% [4].…”

“…For TPV systems, electrical efficiencies above the 2% experimentally reported [4], using a stable and uniform emitter at the design temperature, are mandatory. To achieve this with the use of a selective filter two important points are to be considered in the TPV design:…”

“…Ge (0.66 eV) TPV cells with a back-surface mirror have been proposed for emitters radiating between 1400 and 1900 K [3], while the traditional Si (1.1 eV) photovoltaic cell is limited below 1.1 µm with poor spectral matching with the source radiation. However, Si is available in large quantities with relatively low cost, being a non-toxic material; it has been proposed for TPV prototype systems using a rare earth selective emitter [4].…”