Size-controlled synthesis and photoluminescence of porous monolithic α-alumina

A modified polyacrylamide gel route is used to synthesize porous monolithic α-alumina. X-ray powder diffraction analysis indicates that the as-prepared samples are rhombohedral α-alumina phase, suggesting that high-purity α-alumina can be prepared by using different chelating agents and sintering at about 1150 °C. The scanning electron microscopic images show that the macropore size of the α-alumina samples is related to the chelating agent. The photoluminescence spectra show that a major emission band around 365 nm and a weaker side band located at 330 nm are observed when the excitation wavelength is 228 nm. Interestingly, the intensity of emission peak at 365 nm decreases with the decreasing pore size. The pore-forming and luminescence mechanisms of porous alumina have been discussed based on the experimental results.