Search

1-Hydroxypyrene (1-HP) is a urinary metabolite of polycyclic aromatic hydrocarbons (PAHs), and can function as a convenient biomarker for human intoxication of PAH carcinogens. The development of simple 1-HP sensors with high sensitivity and fast response is highly desirable. Herein, we demonstrate that a robust microcrystalline MOF with fluorescent pyrene cores, NU-1000, exhibits sensitive luminescence detection of urinary 1-HP. The pyrene core within NU-1000 behaves as the signal converter, whose luminescence is significantly quenched upon coming into contact with 1-HP owing to the efficient π-π charge transfer interactions between highly conjugated 1-HP and pyrene cores in NU-1000. The pore confinement effect of the molecular-sized channel of NU-1000 facilitates the preconcentration of 1-HP within NU-1000, which makes 1-HP contact with NU-1000 more sufficient therefore enhancing the detection efficiency. The charge transfer-related quenching mechanism is elucidated by diffuse-reflectance UV-vis and electron paramagnetic resonance (EPR) measurements, and a radical pair state is observed in NU-1000 upon accommodation of 1-HP. This work provides important insights into the development of MOF-based luminescent sensors for 1-HP, and should stimulate further studies toward designing more efficient MOFs with highly conjugated luminescent cores for 1-HP sensing.

Residual antibiotic tetracycline (TC) that is hard to degrade and active has adversely affected public health and ecosystems. Therefore, developing straightforward, rapid, and sensitive probes for TC detection is highly desirable. Herein, we present a facile yet versatile strategy to design and fabricate luminescence turn-on TC sensors by applying the concept of indicator displacement to metal–organic frameworks (MOFs). It is illustrated by an elaborated dual-emitting nanoporous europium–MOF (Eu–MOF) constructed by Eu3+ cations and 2-aminoterephthalic acid (BDC-NH2), in which the former serves as receptors and the latter acts as luminescent indicators. The indicator displacement is based on the competitive interactions within Eu–MOF, which is confirmed by high-resolution mass spectrometry, photoluminescence, and UV–vis spectroscopy. Once Eu–MOF contacts TC, the competitive coordination effect induces the release of BDC-NH2 molecules and the accompanying turn-on blue emission, whereas the red emission of Eu3+ barely changes, thereby resulting in a remarkable ratiometric luminescence response and luminescence color switching from red to blue that is readily observed by the naked eye. The sensitive and quantitative determination of TC is accomplished through multiple readouts involving ratiometric emission intensity and emission color, exhibiting detection limits of 0.08 and 0.95 μM, respectively. Notably, the visual detection of TC is achieved using a smartphone color-scanning app. Considering the excellent tunability in the composition and structure of MOFs and their compatibility with various host–guest interactions applicable to indicator displacement assays, this study helps to create a universal avenue for leveraging MOFs in constructing luminescence turn-on sensors. [ABSTRACT FROM AUTHOR]

[Display omitted] • The in-situ confined growth of CsPbX 3 was achieved in a hierarchically porous MOF. • A one-step perovskite precursor-impregnation approach was demonstrated. • The nanoconfined CsPbX 3 show bright luminescence and enhanced stability. • A primary WLED device showing a NTSC value of 125% was fabricated. Confining metal-halide perovskites within MOF hosts not only protects them from exterior environment stimulation and isolates them from each other without aggregation, but also enables a variety of new features and applications. In this work, a hierarchically porous MOF host was firstly explored for in-situ confined growth of CsPbX 3 perovskite nanocrystallites (PNCs). Compared with the previously used microporous MOF matrixes, this hierarchically porous MOF not only enables the impregnation of perovskite precursors in one step, but also allows more facile diffusion of the reactants, thus giving rise to high loading capacities and uniform distribution of CsPbX 3 perovskites. The MOF matrix serves as both template to guide the confined growth of monodispersed CsPbX 3 PNCs and encapsulation to enhance the stability of CsPbX 3 PNCs. The obtained CsPbX 3 @MOF nanocomposites show bright luminescence and good resistance to ambient moisture, UV light irradiation, and anion-exchange. By integrating the green-emitting CsPbBr 2 I@MOF and red-emitting CsPbI 3 @MOF nanocomposites with a commercial blue InGaN LED chip, we fabricate a primary WLED showing a NTSC value of 125% and Rec. 2020 of 93%, which highlights the potential in backlight display. [ABSTRACT FROM AUTHOR]

In this work, dual-responsive luminescent Her@Zn-Bim hybrids are developed by herniarin (Her) dye encapsulation engineering within a layered host MOF (Zn-Bim). The pore confinement effect of the Zn-Bim host effectively isolates the guest dye molecules, therefore affording bright blue dye emission for Her@Zn-Bim hybrids. Upon exposure to tetracycline antibiotics (TCs), the hybrid undergoes a significant quenching of the blue emission, concurrent with the appearance of a distinct green emission. This dual-emission response is very fast and sensitive, facilitating real-time ratiometric detection of TCs with a low limit of detection of 7.81 nM. Notably, the ratiometric luminescence response manifests as a readily observable blue-to-green color switching, enabling straightforward and colorimetric visualization of TCs. Visual and semiquantitative monitoring of TCs is achieved using a readily available smartphone installed with a color-analysis app. Furthermore, in conjunction with principal component analysis, the Her@Zn-Bim hybrids demonstrate efficient discrimination of four TCs with high structural and chemical similarities, even in complex mixture systems. The mechanisms underlying the luminescent responses of the hybrids towards TCs are carefully elucidated. These hybrid sensors, featuring high sensitivity, fast response, colorimetric visualization, and precise discrimination capability, hold promising potential for practical applications in sensing TCs. [Display omitted] • Dual-responsive luminescent dye@MOF hybrids are developed by dye encapsulation engineering. • The hybrids show dual-emission responses and blue-to-green color switching towards tetracyclines. • The dual-emission responses are very fast and sensitive. • Ratiometric trace detection and real-time colorimetric visualization of tetracyclines are achieved. • Effective discrimination among four tetracyclines is also accomplished when coupled with PCA. [ABSTRACT FROM AUTHOR]

[Display omitted] • First systematic review on the stimuli‐responsive luminescent MOFs for anticounterfeiting. • The responsive mechanisms toward various stimulus are discussed. • The implementation strategies for advanced anti‐counterfeiting are presented. • Challenges and prospects of anticounterfeiting based on responsive luminescent MOFs are discussed. Smart stimuli-responsive luminescent metal–organic frameworks (MOFs), combining the unique advantages and exciting application prospects, have gained booming development in recent years. The powerful capability to respond the external chemical or physical stimuli through various manners makes them particularly attractive in anti-counterfeiting technologies. This review aims at the recent progress of the stimuli-responsive luminescent MOF materials for advanced anti-counterfeiting technologies. The representative types of stimuli, such as light, temperature, solvent, pH, ion are summarized. In addition, the responsive luminescence and mechanisms, and the implementation strategies for advanced anti-counterfeiting are discussed. We also briefly present the current challenges and future perspectives of stimuli-responsive luminescent MOF materials for anticounterfeiting application. We hope this review would provide some new insights and guidelines for the design and engineering of novel stimuli-responsive luminescent MOF materials for advanced anticounterfeiting and information encryption. [ABSTRACT FROM AUTHOR]

[Display omitted] The development of efficient and stable white-light emissive materials is highly desirable in displays and solid-state lighting. Here we present a high-quality white-light emitter based a dual-emitting MOF hybrid, which is achieved by dye encapsulation engineering within a robust Zr-MOF (PCN-128W) containing a highly luminescent tetraphenylethylene-based ligand. The pore confinement effect well isolates the incorporated dye molecules (trans-4-[4-(Dimethylamino)styryl]-1-methylpyridinium iodide (DSM)) and therefore suppress the aggregation caused luminescence quenching. The dye emission is mainly sensitized by PCN-128W host through Förster resonance energy transfer (FRET), and the FRET process is incomplete, thus enabling the hybrid to feature dual emissions upon a single excitation. The emission color of DSM@PCN-128W hybrid can be systematically tuned from blue to white, and to orange by regulating the dye encapsulation content. A broad white-light emission with a considerably high quantum yield (21.2%) is obtained in the case of dye contents of 0.15 wt%. The luminescence of DSM@PCN-128W hybrid is stable in ambient air for over 1 month, and show good resistance to continuous UV light irradiation, owing to the protective MOF Matrix that largely inhibits the UV exposure to dye molecules. What's more, by combining DSM@PCN-128W with a commercial UV LED chip, we fabricate a white-light emitting prototype device showing CIE chromaticity coordinates of (0.34, 0.33), a CRI of 79.1, and a CCT of 5525 K. [ABSTRACT FROM AUTHOR]

Luminescent MOF materials with tunable emissions and energy/charge transfer processes have been extensively explored as ratiometric temperature sensors. However, most of the ratiometric MOF thermometers reported thus far are based on the MOFs containing photoactive lanthanides, which are potentially facing cost issue and serious supply shortage. Here, we present a ratiometric luminescent thermometer based on a dual-emitting lanthanide-free MOF hybrid, which is developed by encapsulation of a fluorescent dye into a robust nanocrystalline zirconium-based MOF through a one-pot synthesis approach. The structure and morphology of the hybrid product was characterized by Powder X-ray diffraction (PXRD), N 2 adsorption-desorption measurement and Scanning electron microscopy (SEM). The pore confinement effect well isolates the guest dye molecules and therefore suppresses the nonradiative energy transfer process between dye molecules. The incorporated dye emission is mainly sensitized by the organic linkers within MOF through fluorescence resonance energy transfer. The ratiometric luminescence of the MOF hybrid shows a significant response to temperature due to the thermal-related back energy transfer process from dye molecules and organic linkers, thus can be exploited for self-calibrated temperature sensing. The maximum thermometric sensitivity is 1.19% °C −1 in the physiological temperature range, which is among the highest for the ratiomtric MOF thermometers that operating in 25–45 °C. The temperature resolution is better than 0.1 °C over the entire operative range (20–60 °C). By integrating the advantages of excellent stability, nanoscale nature, and high sensitivity and precision in the physiological temperature range, this dye@MOF hybrid might have potential application in biomedical diagnosis. What’ more, this work has expanded the possibility of non-lanthanide luminescent MOF materials for the development of ratiometric temperature sensors. [ABSTRACT FROM AUTHOR]