Zeolite-Encaged Luminescent Silver Nanoclusters

The exponential increase in the use of mobile phones and portable devices has led to a greater demand for cheap and lightweight yet efficient light-emitting diodes (LEDs). With the significant research interest in nanoporous organic frameworks, including metal−organic frameworks, covalent organic frameworks, and hydrogen-bonded organic frameworks (MOFs, COFs, and HOFs), their applications in electronics, and particularly as LEDs, have been growing. This review summarizes the main nanoporous MOFs, COFs, and HOFs applied as LEDs that have been reported in the past 10 years. The reported studies are mainly classified depending on the types of organic precursors involved, so as to provide insight into a predesignable approach for LEDs based on these types of nanoporous frameworks that can later be commercialized and integrated into the industry of mobile technology.

Section: Introductionmentioning

confidence: 99%

Nanoporous Organic Frameworks as Light-Emitting Diodes: A Review

Shehayeb,

2024

“…Therefore, it is crucial to confine the ultrasmall Ag NCs in suitable matrixes to limit their overgrowth and meanwhile provide appropriate crystal fields and site symmetry for tunable emission. So far, various host materials and related synthesis approaches have been applied to stabilize Ag NCs with different sizes and chemical states, such as the organic DNA/RNA, proteins, and polymers, as well as the inorganic glasses and zeolites. − …”

Section: Introductionmentioning

confidence: 99%

Luminescence Properties and Theoretical Modeling of the Ag₃ Cluster Confined inside the D6r Cavity of Faujasite Zeolite: Implications for the Design of Tunable Emission Phosphor

Pan,

Ye,

Huang

et al. 2024

Self Cite

Faujasite (FAU) zeolites with abundant exchangeable sites are ideal hosts for the intake of Ag + and the stabilization of highly luminescent silver nanoclusters (Ag NCs), while theoretical calculations on the spectral characteristics, charge states, and electronic energies of Ag NCs that are confined inside FAU zeolite were seldom reported. In this research, the Na-type FAU zeolites with varying silicon-to-aluminum (Si/Al) ratios were first synthesized with the hydrothermal method and then applied as matrixes to stabilize Ag NCs to obtain tunable emissions. With the decrease in the Si/Al ratio, the Ag NCs show red-shifted emission from 515 to 548 nm and broadened photoluminescence of excitation (PLE) and photoluminescence (PL) spectral profile. The time-dependent density functional theory (TD-DFT) method was carried out to probe the effect of Al substitution on the charge states and the optical properties of Ag NCs confined inside the double-six ring (D6r) cavity. The simulated results of the absorption spectra and energy levels suggest that the S 1 → S 0 transition of the monovalent Ag 3 + cluster is responsible for the visible emission, and the increased full width at half-maximum (fwhm) of the PLE and PL spectra in the low Si/Al ratio FAU zeolites is due to the inhomogeneous broadening brought by the increased isomer numbers of the Al-substituted neutral zeolite framework. It is noted that the peak of the simulated absorption spectra red-shifted with the decrease in the Si/Al ratio, which is consistent with the experimental observation. This research provided an effective method for the manipulation of Ag NC emission in FAU zeolites through framework cation substitution and meanwhile theoretically explained the Si/Al ratio dependence of tunable emission properties, which may benefit the design of zeolite-confined Ag NCs with desirable optical performances.

“…Luminescent silver nanoclusters (Ag-NCs) encapsulated within zeolites can have outstanding emissive properties including large Stokes shifts, high external quantum efficiencies (EQEs), and exceptional photostability, among others. , These optical properties depend not only on the zeolite framework, the Ag loading, and the presence of specific counterbalancing ions but also on the hydration conditions. This remarkable versatility allows for a tunable optical emission that spans nearly the entire visible range and can achieve EQEs approaching unity. − These features render zeolite-stabilized Ag-NCs as promising phosphors for LEDs and as active layers in electroluminescent devices .…”

Section: Introductionmentioning

confidence: 99%

White-Light Emissive Silver-Exchanged Nanoporous NaP1 Zeolites

Moreno-Torres,

Lecharlier,

Espejel-Ayala

et al. 2024

Silver nanoclusters (Ag-NCs) encapsulated into zeolite scaffolds, a class of photostable luminescent nanomaterials, have aroused great interest due to their attractive photoluminescence (PL) properties and promising applications as alternative phosphors for light-emitting devices. However, current research predominantly features single-color emitters in luminescent Ag-exchanged zeolites. Herein, the synthesis and characterization of white-light emissive Ag-exchanged NaP1 zeolites obtained from natural clinoptilolite through hydrothermal processes are described. Samples were subjected to X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), steady-state PL spectroscopy, and fluorescence microscopy analysis. Optically and chemically pure NaP1 zeolites were obtained from nonconventional precursors and subsequently exchanged with Ag loadings (12.5, 25, 33, 50, and 66 wt %), resulting in luminescent samples after a thermal activation at 450 °C with quantum efficiencies of up to 6.2% and a broad emission band (full width at half-maximum = 31250 cm–1) when excited at 380 nm. The strategy to obtain white-light emissive materials presented in this study opens alternative avenues for the development of sustainable phosphors, decreasing the burden of nonrenewable resources.