Search

The dynamic manipulation of multi-photon upconversion, enabling rich and tunable emission colors, has generated significant interest in lanthanide-doped upconversion nanoparticles (UCNPs) about their fundamental research and frontier applications. However, manipulating photochromic upconversion emissions towards luminescent color tuning (LCT) of a single UCNP emitter without tedious endogenous regulation remains a challenging endeavor. In this study, NaYF4@NaYF4:x%Yb, 2%Er (X = 60, 80 and 98) was incorporated with UiO-66-type metal–organic frameworks (MOFs, including UiO-66, UiO-66-NDC, UiO-66-NH2) by a simple and versatile in situ synthesis method. The UCNPs are combined with MOFs in a monodisperse state, and the stability of the composites is improved compared to UCNPs alone. Effective modulation of the upconversion luminescence (UCL) properties of UCNPs was achieved by exploiting the chemical bonds with high-energy vibrations in MOFs, which facilitates the multi-phonon relaxation (MPR) processes of Er3+. Our findings enable versatile designs and dynamic control of emission colors from luminescent materials, opening up new opportunities for their advanced photonic applications, notably in optical anti-counterfeiting. [ABSTRACT FROM AUTHOR]

Development of highly porous and robust hydrogen‐bonded organic frameworks (HOFs) for high‐pressure methane and hydrogen storage remains a grand challenge due to the fragile nature of hydrogen bonds. Herein, we report a strategy of constructing the double‐walled framework to target highly porous and robust HOF (ZJU‐HOF‐5a) for extraordinary CH4 and H2 storage. ZJU‐HOF‐5a features a minimized twofold interpenetration with double‐walled structure, in which multiple supramolecular interactions are existed between the interpenetrated walls. This structural configuration can notably enhance the framework robustness while maintaining its high porosity, affording one of the highest gravimetric and volumetric surface areas of 3102 m2 g−1 and 1976 m2 cm−3 among the reported HOFs so far. ZJU‐HOF‐5a thus exhibits an extremely high volumetric H2 uptake of 43.6 g L−1 at 77 K/100 bar and working capacity of 41.3 g L−1 under combined swing conditions (77 K/100 bar→160 K/5 bar), and also impressive methane storage performance with a 5–100 bar working capacity of 187 (or 159) cm3 (STP) cm−3 at 270 K (or 296 K), outperforming most of the reported porous organic materials. Single‐crystal X‐ray diffraction studies on CH4‐loaded ZJU‐HOF‐5a reveal that abundant supramolecular binding sites combined with ultrahigh porosities account for its high CH4 storage capacities. Combined with high stability, super‐hydrophobicity, and easy recovery, ZJU‐HOF‐5a is placed among the most promising materials for H2 and CH4 storage applications. [ABSTRACT FROM AUTHOR]

It is imperative to develop a comprehensive understanding of phase separation mechanisms in multi‐phase oxy‐fluoride glass ceramics (GCs) to customize their structural and optical characteristics for particular applications in photonics. The manuscript utilizes molecular dynamics (MD) simulations to examine the phase separation mechanisms in SiO2–Al2O3–SrF2–ZnF2–LnF3‐CrF3 (where Ln represents the lanthanide elements) GCs during the simultaneous precipitation of SrF2: Ln3+ and ZnAl2O4: Cr3+ nanocrystals. Insights into the atomic‐level interactions that regulate the separation and formation of distinct phases rich in fluoride and oxide are obtained through MD simulations. The results reveal that Sr2+ and Ln3+ ions partition preferentially into the fluoride phase, whereas Zn2+ and Cr3+ associate with the oxide aluminosilicate network. Remarkably, the separated fluoride and oxide phases bear structural similarities with the existing experimental outcomes. The introduction of SrF2 facilitates phase separation in oxy‐fluoride glass system by causing the formation of SrF2: Ln3+ nanocrystals in regions abundant in fluoride, while the substitution of ZnF2 for SrF2 results in the formation of ZnAl2O4: Cr3+ nanocrystals originating from the separated oxide phase. Therefore, the reported simulations offer molecular‐level insights into the mechanisms underlying phase separation and the functions of various glass components, thereby facilitating the development of customized oxy‐fluoride GCs with tailored properties. [ABSTRACT FROM AUTHOR]

Microporous hydrogen-bonded organic frameworks (HOFs) have been considered promising materials for ethane/ethylene (C2H6/C2H4) separation owing to their native nonpolar pores. However, the absence of functional binding sites on nonpolar pore surfaces commonly limits their separation performance. Herein, we report and construct a novel HOF material (termed as ZJU-HOF-60a) by incorporating electron-rich alkynyl groups into its pore surfaces to achieve highly efficient C2H6/C2H4 separation. The incorporated alkynyl groups not only serve as functional binding sites to provide multiple supramolecular interactions with the C2H6 molecule, but also do not participate in the formation of any hydrogen bonds in order to obtain the desired HOF framework. Alkynyl-functionalized ZJU-HOF-60a thus exhibits both a top-tier C2H6 uptake capacity of 3.79 mmol g−1 and C2H6/C2H4 uptake ratio of 1.58 at 296 K and 1 bar, surpassing most of the previously reported C2H6-selective HOFs. Theoretical calculations indicate that the incorporated alkynyl groups combined with the surrounding carboxylic groups provide stronger and more number of C–H⋯π and C–H⋯O interactions to bind with C2H6 over C2H4, thus accounting for efficient C2H6/C2H4 separation. The actual separation performance of ZJU-HOF-60a was confirmed using breakthrough experiments for 50/50 (v/v) C2H6/C2H4 gas mixtures, affording a highly pure C2H4 productivity of 7.8 L kg−1 under ambient conditions. [ABSTRACT FROM AUTHOR]

Chemiluminescence can eliminate interference caused by excitation light sources, thereby providing ultrasensitive imaging for the detection of various diseases. In this work, we report a novel chemiluminescent system by encapsulating luminol and Co2+ within a metal–organic framework (MOF) UiO-67-bpydc. Due to the chelation of the Co2+ on the N-site from the ligand as well as the confinement of luminol within the pores of UiO-67-bpydc, the synthesized MOF composite UiO-67-bpydc⊃Co+Lu exhibits significantly enhanced chemiluminescence intensity, which is 8300 times higher than that of luminol. The potential practical application of UiO-67-bpydc⊃Co+Lu was also evaluated by the quantitative analysis of H2O2 and glucose. The results indicate that the H2O2 and glucose could be linearly detected over the range from 10 to 100 μM with a detection limit of 0.52 μM and 10 to 400 of μM with a detection limit of 1.36 μM, respectively. By taking advantage of the sensitive sensing properties and excellent biocompatibility, chemiluminescence imaging of skin inflammation in mice was demonstrated utilizing UiO-67-bpydc⊃Co+Lu. This work provides inspiration to design highly emissive chemiluminescent materials for use in diagnosis. [ABSTRACT FROM AUTHOR]