Visible emission from Ag⁺exchanged SOD zeolites

Abstract

Broad visible emissions dominant at green or red have been observed for the thermally-treated Ag(+) exchanged SOD zeolites, determined by the Ag(+) loading contents and the excitation wavelengths. Contrary to the notable reversible green/red dominant emission evolution in the Ag(+) exchanged LTA zeolites upon hydration/dehydration in air (or water vapor)/vacuum, emission spectra of the Ag(+) exchanged SOD zeolites are insensitive to the environmental change. This is most probably due to the difficult H2O permeation in SOD zeolites in comparison with LTA zeolites. By combining the environment dependent emission spectra of the Ag(+) exchanged LTA and SOD zeolites, we proposed the following emission mechanisms for Ag(+) exchanged LTA and SOD zeolites: the green emission is due to the transition from ligand-to-metal (framework O(2-)→ Ag(+)) charge transfer state to the ground state and the red emission is due to the transition from the metal-metal (Ag(+)-Ag(+)) charge transfer state to the ground state. The insensitive environment dependent emission characteristics of Ag(+) exchanged SOD zeolites may have potential applications as robust phosphors.

Tunable luminescence of silver-exchanged SOD zeolite thermally treated under mild conditions

“…The X-ray diffraction (XRD) results of the as-synthesized SOD zeolites are presented in Fig. 1b, which were well consistent with a previous report, 28 indicating the successful synthesis of the SOD zeolites. The luminescent phosphors were prepared by incorporating Ag + ions into the as-synthesized SOD zeolites and then heated at different temperatures (200 °C or 300 °C) in air atmosphere for 3 h, 6 h, 9 h or 12 h. According to the addition amounts of Cs + and Ag + in the initial solution, we obtained partially exchanged zeolites denoted as y Ag-SOD or x Cs- y Ag-SOD.…”

“…This implies that the atom number of the silver nanoclusters gradually increases as the Ag loading increases, which is in good agreement with the results reported previously. 23,28…”

“…26,27 Lin et al reported the Ag + loading and excitation wavelength-dependent luminescence from silver-exchanged SOD zeolites, and broad emissions in the green or red region were observed. 28 We achieved interesting white emission by heating Ag + , Eu 3+ and Zn 2+ co-doped SOD zeolite at 800 °C, packing the NUV-LED with which produced warm WLED devices with CIE color coordinates of (0.37, 0.35), a lower CCT of 4041 K, and a higher Ra of 87. 29 It is worth noting that we gain white emission in the silver-exchanged SOD zeolite under mild thermal treatment (100–300 °C), and the tunable emission from blue, yellow, and orange to warm white was realized by changing counterbalancing cations, thermal-treatment temperature and Ag loading.…”

Confinement of Highly Luminescent Silver Nanoclusters in FAUY Zeolite: A Study on the Formation Effects of Silver Nanoclusters and the Sensitization of Tb3+

“…It is well-known that the reduction of Ag + for the formation of Ag NCs requires electrons, which can be obtained from O 2− in hydration water or the zeolite framework; the corresponding reaction can be described as 4Ag + + 2O 2− → 4Ag 0 + O 2 ↑. 5,33,38,47,48 Previous studies suggested that the coexistence of RE ions such as Eu 3+ and Tb 3+ can suppress the above reaction by isolating Ag + from water molecules or bonding with the framework oxygen, therefore hindering the formation of Ag NCs. 2,16,40 This is consistent with our XPS results in Table 1 that with the loading and increased loading amount of Tb 3+ , the atomic percentage of O left increased from 52.13 to 65.21%, indicative of less efficient Ag NCs formation.…”

Simultaneous Time-Resolved Photoluminescence and X-Ray Absorption Fine Structure Operando Measurement during Ag Cluster Formation in Ag Zeolite X

“…The fact that Ag-exchanged zeolites exhibit luminous properties despite containing no rare earth metal component indicates zeolite as a promising luminescent material for future use. In recent years, many researchers have investigated the luminescence behavior of silver-exchanged zeolites [10][11][12][13][14][15][16][17][18]. Many reports have described that Ag clusters formed with a zeolite framework are luminescent species.…”