Stable and Highly Luminescent Silver Nanoclusters in the 13X Zeolite Enabled by Mg²⁺ Doping and Their Luminescence Tuning by Heating Temperature

Abstract

Zeolite-confined silver nanoclusters (Ag-zeolite) have aroused vast interest due to their remarkable luminescence. The countercations within a zeolite play critical roles in determining the luminescent properties of the resulting Ag-zeolite. We observed, in this work, that introducing Mg 2+ enabled the Ag-13X zeolite a stable and bright yellow emission with a high PLQY of 94.6%, the first report on the luminescence enhancement of the Ag-13X zeolite by Mg 2+ , to the best of our knowledge. The formation of specific internal electric fields inside 13X and the structural contraction of the zeolite framework due to the high charge density and the small ionic radius of Mg 2+ are believed to be responsible for the enhanced stable and bright yellow emission. The stabilization effect of Mg 2+ is removed by increasing the heating temperature above 700 °C, which leads to the variation of silver nanoclusters as a result of the framework collapse of the zeolite. The Ag-zeolite synthesized by us, featured with a broad emission band, a high PLQY of 94.6%, and good thermal stability, can be considered a suitable candidate to replace the traditional commercial yellow-emitting phosphor YAG:Ce 3+ for light-based applications. This work contributes to a valuable reference for the rational design of silver nanoclusters confined in zeolites with promising new functionalities and stimulates potential applications as novel phosphors for near-ultraviolet light-emitting diodes (NUV-LEDs).

Emission-tunable silver clusters constrained within EMT zeolite

“…In the synthesis process of the material, not only Ag NCs are formed in the pores and cages of zeolites, but also many non-emissive Ag NPs are formed on the surface of zeolites. 32,36 Interestingly, we observed that the zeolite modified by PEG400 is more likely to form larger and more uniformly dispersed Ag NPs when used as a scaffold to stabilize nanoclusters (Fig. 2A and D), which may be caused by the increased exchange capacity of silver ions.…”

“…28 In the subsequent publication, we reported controllable luminescence of silver-loaded composites by adjusting guest–host–guest interactions, such as changing counter-balancing ions, activating temperatures, and assisting with terephthalic acid (TPA). 28–32 However, to our knowledge, the influence of zeolite surface modification on the luminescence capabilities of Ag-NCL@zeolites is rarely reported.…”