Features of the electroluminescence of aluminum and its nanoporous oxide in esters and ketones

On the example of esters of carboxylic and dicarboxylic acids (ethyl acetate, diethyl oxalate, diethyl malonate, diethyl phthalate and dibutyl phthalate), as well as ketones, lactams and diketones (acetone, cyclohexanone, 4-ethylpropiophenone, acetylacetone and methylpyrrolidone) studies were carried out to generate electroluminescence (EL) in them of pure aluminum (Al) and preoxidized (Al$_{2}$O$_{3}$) in distilled water. The absence of EL in pure Al in ethers was revealed, and the regularities of luminescence generation in them for the oxidized metal were established. It was shown that in ketones and related compounds – lactams and diketones, the appearance of EL is possible for both states of the Al anode. In this case, the EL spectra have broad bands in the range 400 – 700 nm with maxima characteristic of the carboxyl and carbonyl groups of the electrolytes used, as well as the nanoporous structure of the formed Al$_{2}$O$_{3}$ and carbon-containing impurities captured by it during the growth. In some ethers and ketones, the effect of transformation of the initial structure of the oxide, as well as an increase in its thickness, was found. The absence of any changes in the chemical composition of electrolytes after anodic oxidation of Al in them or transformation of Al$_{2}$O$_{3}$ was established by UV, IR and NMR spectroscopy.