Effect of heat treatment on the structure of incorporated oxalate species and photoluminescent properties of porous alumina films formed in oxalic acid

Blue photoluminescence of sponge-like highly porous alumina synthesized in hydrofluoric acid based electrolytes

“…It is to be noted that obtained values are in satisfactory agreement with each other in shown ± 0.05 eV scatter. It is known that luminescence centers of AAO synthesized in (COOH) 2 are complexes based on oxygen vacancies and/or oxalate-ions impurities formed during oxidation process [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. Electrolyte composition in current work excluded presence of oxalate-ions.…”

“…Numerous studies considering luminescent properties of anodic aluminum oxide synthesized in electrolytes of various type and composition have been conducted up to date [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. The most intensive emission with maximum in 430 -500 nm range was demonstrated by amorphous as-grown nanostructures anodized in oxalic acid based solutions [6][7][8][9].…”

“…The most intensive emission with maximum in 430 -500 nm range was demonstrated by amorphous as-grown nanostructures anodized in oxalic acid based solutions [6][7][8][9]. A major contribution in mechanisms of observed luminescence were made by defects attributed to oxygen vacancies in different charge state [7,[10][11][12][13][14][15][16][17][18] and/or oxalate-ions impurities [8,9,[19][20][21][22]. Therefore, it is of current interest to search for optimal anodizing modes and electrolytes composition in order to obtain nanostructured oxide layers with high concentration of optically active defects formed due to developed surface with big specific area.…”

The effect of annealing on the photoluminescent and optical properties of porous anodic alumina films formed in sulfamic acid

“…Most investigators have focused their attention to PL of porous oxide films formed in oxalic acid [6][7][8][9][10][11][12][13][14][15][16][17][18]. Little has been done on the PL of porous oxide films formed in sulfuric acid and phosphoric acid [6,9,17,19].…”

Photoluminescence properties of heat-treated porous alumina films formed in oxalic acid

“…The effect of excitation wavelength [7], the way of sample preparation [8], and the treatment temperature of porous alumina films [9][10][11][12] on photoluminescence properties has been studied recently. The most essential effect found in anodic alumina films formed in oxalic acid was the increase in photoluminescence intensity with the temperature of the treatment at a wavelength of excitation equal or greater than 330 nm.…”