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

► Photoluminescence and optical properties of porous alumina films have been studied. ► In anodic alumina the oxalate ions are embedded as chelating bidentate structures. ► The results show the presence of two luminescence centers. ► The F+-centers are responsible for the peak at 420 nm with a lifetime of 4.0 ns. ► The peak at 480 nm with a lifetime of 0.25 ns can be attributed to carboxylate ions.