Investigation on existing states and photoluminescence property of silver in the SiO2 three-dimensionally ordered macroporous materials

The photoluminescence properties of silver species, including Ag+, Ag+-Ag+, Ag-0, and Ag nanoparticles in various matrices, such as gel and glass have been extensively reported. In the present study, we present the preparation of silver including SiO2 three-dimensionally ordered macroporous (3DOM) materials and investigate the existing states and photoluminescence property of silver in the SiO2 3DOM materials. The results show that only Ag+ ions exist in the SiO2 3DOM materials sintered at temperature below 400 degrees C. With the increasing sintering temperature, the Ag+ ions gradually transform into Ag+-Ag+, where simultaneously, a part of Ag+-Ag+ transform into Ag nanoparticles. The Ag+-Ag+ and Ag nanoparticles are formed in the SiO2 3DOM materials sintered at temperature from 450 to 650 degrees C. Finally, only Ag nanoparticles occur in the SiO2 3DOM materials prepared at 750 degrees C. The formation mechanisms of Ag species were discussed in the SiO2 3DOM materials.