Macroporous Y3Al5O12 doped with Ce 3+ (YAG:Ce) ceramics has been prepared using the metal salt-derived sol-gel processing followed by the heat treatment at temperatures of 800 to 1500 °C. The obtained YAG:Ce crystal exhibits a broad emission band around 530 nm ascribable to 5d-4f transitions of Ce3+. Irradiation of the samples with an intense laser light from a He-Cd laser (wavelength 442 nm) leads to a decrease in the fluorescence intensity, indicating the occurrence of photoionization of Ce3+ and subsequent capture of excited electrons by some trapping sites. It is found that the rate of the photobleaching decreases with an increase in size of YAG crystallites, depending on the temperature of heat treatment
photobleaching takes place more rapidly when heat treatment is performed at lower temperatures, while the heat treatment at higher temperatures suppresses the bleaching. © Published under licence by IOP Publishing Ltd.