Application of transparent conductive oxides films for high-temperature solar selective absorbers

At present, the utilization of thermal energy from sunlight has been widely adopted as the working principle of concentrated solar power (CSP) generation systems. In this research, we suggest a CSP technology based on the properties of transparent conductive oxide (TCO) films on metal substrates which is compatible with mass production of solar selective absorbers that can be utilized at high temperatures. TCO material has plasma wavelength in infrared region. Therefore the electromagnetic wave with shorter wavelength than plasma wavelength goes through the material, while the electromagnetic wave with longer wavelength is reflected on the surface. By coating metal surface with a TCO film, interference is occurred in transparent wavelength range of TCO. Therefore, solar energy is highly absorbed, though thermal radiation from the absorber is suppressed. The optical property of fabricated TCO coated metal is well consistent with the simulated property. It is revealed that the performance of the absorber is improved by fabricating microstructures on the metal substrate. Thermal stability is confirmed at 700°C in vacuum for 3 hours. Solar absorptance and hemispherical emittance of the fabricated absorber are 0.82 and 0.17, respectively, which is comparable to that of commercialized absorbers.