Electroluminescence of Anodic Aluminum Oxide in Ketones

Transformation of the Nanoporous Structure of Anodic Aluminium Oxide and its “Nonelectrolysis” Electroluminescence

“…kV and a temperature of 298 K, it was anodized in distilled water (DW) with specific electrical conductivity (1.7 ± 0.2)•10 -4 S/m. After that, for 800 s at the same voltage and temperature in the studied ketone, the luminosity kinetics of the EL ) (t I of the oxidized Al-anode and the current density ) (t J flowing in the electrolytic cell previously described in [12] were recorded. In order to identify electrolysis processes at the anode in ketones, a similar procedure was carried out for pure metal for 1700 s. At the time of application of voltage, the EL on the oxidized anode was flare in nature, obeying previously established laws [12].…”

“…After that, for 800 s at the same voltage and temperature in the studied ketone, the luminosity kinetics of the EL ) (t I of the oxidized Al-anode and the current density ) (t J flowing in the electrolytic cell previously described in [12] were recorded. In order to identify electrolysis processes at the anode in ketones, a similar procedure was carried out for pure metal for 1700 s. At the time of application of voltage, the EL on the oxidized anode was flare in nature, obeying previously established laws [12]. For a pure metal, the luminescence intensity had a smooth increase with reaching a stationary level in the case of Acac and Mp, while in Ac any light radiation was not detected.…”

“…formed in the surface and near-surface layers of the Al2O3 film that differs significantly from its deep organization. For this reason, in our previous publication [12], the pore diameter was overestimated by the indicated value, since it was estimated from pores located on the surface. The same applies to the Al2O3 thickness, previously theoretically estimated by formula (3) of work [14].…”

“…To reduce or possibly eliminate such an effect, it was proposed to separate the electrolysis processes from EL processes by preliminarily forming films on the example of Al2O3 in chemically pure water with their subsequent immersion in electrolytes that slightly or completely do not decompose when current flows. These turned out, in particular, to some esters [11], ketones and related compounds containing fragments from carbonyl groups (CNG) [12]. The highest brightness was found on the oxidized Al-anode in acetylacetone (Acac) and methylpyrrolidone (Mp) in comparison with the simplest representative of ketones -acetone (Ac) [12].…”

“…These turned out, in particular, to some esters [11], ketones and related compounds containing fragments from carbonyl groups (CNG) [12]. The highest brightness was found on the oxidized Al-anode in acetylacetone (Acac) and methylpyrrolidone (Mp) in comparison with the simplest representative of ketones -acetone (Ac) [12]. Moreover, it was found that it is precisely in the "brightest" electrolytes when EL is generated that a significant transformation of the nanoporous Al2O3 structure occurs compared to the initial one.…”