Ultrasonic spray pyrolysis technique to generate a solar absorber coating of Mn-doped α-Fe₂O₃

Abstract

Today, even though exist a Titanium Nitride Oxide, TiNOX, a very good commercial solar absorber, the efforts to develop new and better solar absorbers like TiNOX are continuing in several laboratories all over the world. In this article, we used the ultrasonic spray pyrolysis technique to prepare manganese, Mn, Mn-doped α-Fe2O3 dark thin films deposited on titanium substrates. The results of an analysis of the solar absorptance and thermal emittance of these films are also presented here; the optical properties depend of the proportions of Mn and iron, Fe, in the spray solution and of the deposit temperature. The best solar absorptance (0.94) and thermal emittance (0.07) values of the films prepared at 600 °C for iron and manganese ion with concentrations of 0.0015 and 0.0035 mol/l, respectively, are comparable with the optical properties of the Titanium Nitride oxide, TiNOX, a very common commercial solar absorber used as an efficient coating for flat plate solar collectors industry.