Hot electron-induced time-resolved electrogenerated luminescence of Tb(III) ions at stationary oxide-covered aluminium electrodes

Cathodic electrochemiluminescence of lucigenin at disposable oxide-coated aluminum electrodes

“…Based on our previous studies [22][23][24][25][26], hydrated electrons are assumed to be the primary reducing species to trigger most of the ECL reaction pathways studied by us so far. In alkaline conditions, ECL intensity started to slightly decrease when pH exceeded 9 due to the thinning of oxide film.…”

“…In previous studies [22][23][24][25][26], we have demonstrated that many kinds of luminophores can be excited by cathodic pulse-polarization at conductor/insulator/electrolyte (C/I/E) tunnel junction electrodes e.g. oxide-coated aluminum, silicon and magnesium electrodes.…”

“…In practice, cathodic reductions may be produced simultaneously by heterogeneously transferred electrons from the bottom of the conduction band of the insulating film, via the surface states of the insulating film and by presolvated hot and hydrated electrons [25]. Meanwhile, strongly oxidizing species such as sulfate and hydroxyl radicals can be cathodically generated from purposely-added coreactants or form dissolved oxygen [22,23,25,33,34]. In addition, F + -centers existing in oxide film of C/I/E electrodes may act as oxidants [2,23,33].…”

“…Meanwhile, strongly oxidizing species such as sulfate and hydroxyl radicals can be cathodically generated from purposely-added coreactants or form dissolved oxygen [22,23,25,33,34]. In addition, F + -centers existing in oxide film of C/I/E electrodes may act as oxidants [2,23,33]. Hence, highly reducing and oxidizing conditions are simultaneously achieved in the vicinity of the electrode surface.…”

“…General ECL excitation routes for luminophores based on our cathodic pulse polarization method have been observed to be reduction-initiated oxidative excitation (red-ox) or oxidation-initiated reductive excitation (ox-red) pathways in which the luminophores are excited by the cathodically generated species at the oxide film/electrolyte interface by successive one-electron transfer steps normally resulting in the luminophore in its original oxidation state but now in its singlet or triplet excited state [22][23][24][25][26]. However, sometimes the ECL mechanism is based on the decomposition of the luminophore [22].…”