Photoluminescence enhancement of Eu3+ ions by Ag species in SiO2 three-dimensionally ordered macroporous materials

The existing states of silver depend on the sintering temperature of SiO2 three-dimensionally ordered macroporous (3DOM) materials. Several species related to silver (Ag+ ions, Ag+-Ag+ and Ag nanoparticles) were demonstrated in SiO2 3DOM materials prepared at 550 degrees C. Only Ag nanoparticles were observed in SiO2 3DOM materials prepared at 750 degrees C. The influence of silver species on the photoluminescence properties of Eu3+ was investigated systematically in SiO2 3DOM materials. The results show that photoluminescence enhancement of Eu3+ ions was induced by Ag species in SiO2 3DOM materials. For the SiO2 3DOM materials prepared at 550 degrees C, the enhancement of Eu3+ luminescence is attributed to energy transfer from Ag+-Ag+ to Eu3+ under excitation at 345 or 280 nm, while the luminescence enhancement of Eu3+ is due to energy transfer from isolated Ag+ to Eu3+ under excitation at 245 nm. For the SiO2 3DOM materials prepared at 750 degrees C, the luminescence of Eu3+ was enhanced due to the plasmon resonance effect of Ag nanoparticles.