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In this research, we report the cathodoluminescence (CL) and preliminary photoluminescence (PL) properties of praseodymium‐doped zinc aluminate powders. ZnAl2O4:Pr powders were synthesized by a very simple chemical process. X‐ray diffraction spectra indicated a cubic spinel crystalline structure with an average crystallite size of 15 nm. CL properties of the powders were studied as a function of the praseodymium concentration and electron‐accelerating potential. In this case, all the cathodoluminescent emission spectra showed main peaks located at 494, 535, 611, 646, and 733 nm, which were associated to the electronic transitions 3P0 → 3H4, 3P0 → 3H5, 3P0 → 3H6, 3P0 → 3F2, and 3P0 → 3F4 of the Pr3+ ions, respectively. A quenching of the CL, with increasing doping concentration, was observed. Also, an increment on cathodoluminescent emission intensity was observed as the accelerating voltage increased. The PL emission spectrum showed similar characteristics to those of the CL spectra. The chemical composition of the powders, as determined by energy dispersive spectroscopy, is also reported. In addition, the surface morphology characteristics of the powders are shown.

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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.