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

Abstract

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.