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 °C. Only Ag nanoparticles were observed in SiO2 3DOM materials prepared at 750 °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 °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 °C, the luminescence of Eu3+ was enhanced due to the plasmon resonance effect of Ag nanoparticles.