Ling Pan,Song Ye,Ruihao Huang,Meiyan Wang,Tianning Zheng,Haoran Zhang,Deping Wang
Luminescent silver clusters that are confined inside porous zeolites have attracted great research interest due to the combined advantages of high quantum yield, tunable emission, excellent chemical stability, and desirable adoption ability of this micronano-composite. In this research, a series of Ag-exchanged R-LTA/Ag (R = Li, Na, K) zeolites were synthesized, in which the silver clusters showed blue-shifted excitation in the UV region, red-shifted emission in the visible region, and decreased emission intensity when taking Li+, Na+, and K+ as the extra-framework cations, respectively. The [Ag4(H2O)xR4-sod]6– (x = 2, 4; R = Li, Na, K) structures were constructed, and the TD-DFT method was further carried out to study the influence of extra-framework cations on the luminescence performance of [Ag4]2+ clusters, in which the substitution of Al for Si and the reasonable hydrate levels were both taken into consideration. It is estimated that the S1 and S3 levels for the [Ag4(H2O)4Li4-sod]6– cluster, the S4 level for the [Ag4(H2O)4Na4-sod]6– cluster, and the S5 level for the [Ag4(H2O)2K4-sod]6– cluster can be effectively populated through direct excitation, and the S1 → S0 transition is assumed to be responsible for the radiative emission in the visible region for the [Ag4]2+ pseudo-tetrahedrons. This calculated energy level diagram and simulated absorption spectra of [Ag4(H2O)xR4-sod]6– (x = 2, 4; R = Li, Na, K) clusters explained the modified luminescence property of silver clusters in R-LTA/Ag (R = Li, Na, K) zeolites studied in this research and reported literature.
Ruihao Huang,Song Ye,Meiyan Wang,Ling Pan,Tianning Zheng,Deping Wang
The manipulation of silver nanoclusters' luminescence performance in heteroatom zeolite was rarely reported. In this research, the heteroatom Ga-FAU zeolites were synthesized together with the Al FAU zeolite, based on which a series of Ag nanoclusters loaded Al FAUAg and mGa FAUAg zeolites were prepared. The spectroscopy characterization indicated that emission intensity of silver nanoclusters is greatly enhanced in Ga-containing zeolites compared to that in Al FAUAg, and meanwhile, the excitation and emission peak showed redshift and blueshift, respectively, with the introduction and increasing proportion of Ga atoms in mGa FAUAg. The TD-DFT method was carried out on the [Ag 3 Ga x D6r] + (x = 0, 1, 2, 3, 4, 5) clusters to study the effect of framework Ga on the luminescence properties of Ag 3 + in the D6r cavity of FAU zeolite, which suggested that the S 1 → S 0 transition of Ag 3 + is responsible for the radiative visible emission. Moreover, the low-energy shift for S 3 → S 0 transition and high-energy shift for S 1 → S 0 transition were observed with increasing x value in [Ag 3 Ga x D6r] + clusters, which is in accordance with the experimental observation. This research provided an alternative method for the manipulation of silver nanoclusters' luminescence performance by using heteroatom zeolite, which contributed to the design of solid phosphors with desirable emission.
危险品化学品经营许可证（带存储）