Influence of oxalic and sulfuric acid electrolyte-mixture on the morphological and photoluminescence (PL) properties of Nanoporous Anodic Alumina (NAA) is reported. Two-dimensional fast Fourier transform of the FESEM images was employed to investigate the pore-arrangement of mixed electrolyte NAA. Pore-properties increased with sulfuric ion concentration and pore-regularity was highest with 1.4M sulfuric acid. Pore regularity is a direct consequence of sulfuric acid concentration at a fixed oxalic acid concentration (0.3M). No obvious PL was observed for NAA prepared in sulfuric acid while those prepared using mixed electrolytes showed strong blue emission. This broad PL comprised of four Gaussian curves (273, 316, 360 and 460nm). First two bands could be ascribed to luminescent centers transformed from sulfuric and oxalic impurities, respectively while the latter two are attributable to oxygen vacancies (F+ and F-centers). PL bands blue-shifted with increasing intensities at higher sulfuric acid concentration. Emission intensity and wavelength could be tailored by varying the electrolyte composition.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials