Three Models To Encapsulate Multicomponent Dyes into Nanocrystal Pores: A New Strategy for Generating High-Quality White Light

Ratiometric fluorescence analysis of tetracycline by dual-ligand europium-based metal-organic framework

It is important to develop sensitive and accurate methods for the detection of tetracycline (TC). For this purpose, a dual emission probe Eu-DPA/BDC-(OH)2 was developed based on the green fluorescence of the ligand 2, 5-dihydroxyterephthalic acid (BDC-(OH)2), and the red fluorescence of Eu3+ sensitized by another ligand 2, 6-pyridine dicarboxylic acid (DPA). TC was able to quench the fluorescence of ligand BDC-(OH)2 at 545 nm by the internal filter effect (IFE), and coordinate with Eu3+ to enhance the fluorescence at 625 nm by the antenna effect (AE). I625/I545 showed a linear relationship with TC concentration with an LOD at 55 nM. At the same time, the fluorescence color of Eu-DPA/BDC-(OH)2 changed from green to yellow to red with the increase of TC concentration. On this basis, the RGB method was also developed for the visual detection of TC with an LOD at 0.2 μM. These methods have been successfully applied for the detection of TC in fish feed and pork with recovery rates of 93 % -110 %, indicating excellent applicability in the detection of real samples.

Stomata-targeted nanocarriers enhance plant defense against pathogen colonization

Plant pathogens significantly threaten food security and agricultural sustainability, with climate change expected to exacerbate outbreaks. Despite these growing threats, current agrochemical delivery remains untargeted and inefficient. In this study, we develop surface ligand-engineered nanoparticles for targeted delivery to stomata (SENDS), a nanocarrier system designed to target stomatal guard cells, which serve as key pathogen entry points into the plant apoplast. Our approach employs rational ligand engineering of porous nanoparticles, optimizing ligand orientation for efficient stomata targeting across different plant species. Foliar application of SENDS encapsulating an antimicrobial plant alkaloid reduces colonization of Xanthomonas campestris, a major crop pathogen, by 20-fold compared to untargeted nanocarriers. Quantitative assessment of stomatal aperture movement and photosynthetic performance confirms that SENDS enhance plant defense against invading pathogens without disrupting natural stomatal function. This nanobiotechnology approach provides a targeted strategy to improve plant disease resistance, offering new insights into nanocarrier design for more resilient and sustainable agriculture.

Functional differentiation visualized: diverse light-emitting modes in biomimetic microstructures

Biomimetic materials of BaCO3-SiO2 biomorphs hybridized with organic dyes were developed to visualize the functional differences among various morphologies. The helicoid microstructures with curved-growth exhibit multistage fluorescence coding characteristics, while the conical microstructures with flat-growth visually exhibit white light emission behavior that is visible due to tricolor spectral superposition.

Emission Library and Applications of 2,1,3-Benzothiadiazole and Its Derivative-Based Luminescent Metal-Organic Frameworks

Organic linker-based luminescent metal-organic frameworks (LMOFs) have received extensive attention due to their promising applications in chemical sensing, energy transfer, solid-state-lighting and heterogeneous catalysis. Benefiting from the virtually unlimited emissive organic linkers and the intrinsic advantages of MOFs, significant progress has been made in constructing LMOFs with specific emission behaviors and outstanding performances. Among these reported organic linkers, 2,1,3-benzothiadiazole and its derivatives, as unique building units with tunable electron-withdrawing abilities, can be used to synthesize numerous emissive linkers with a donor-bridge-acceptor-bridge-donor type structure. These linkers were utilized to coordinate with different metal nodes, forming LMOFs with diverse underlying nets and optical properties. In this Minireview, 2,1,3-benzothiadiazole and its derivative-based organic linkers and their corresponding LMOFs are summarized with which an emission library is built between the linker structures and the emission behaviors of constructed LMOFs. In particular, the preparation of LMOFs with customized emission properties ranging from deep-blue to near-infrared and sizes from dozens to hundreds of nanometers is discussed in detail. The applications of these LMOFs, including chemical sensing, energy harvesting and transfer, and catalysis, are then highlighted. Key perspectives and challenges for the future development of LMOFs are also addressed.

Full-Color Emissive Zirconium-Organic Frameworks Constructed via in Situ "One-Pot" Single-Site Modification for Tryptophan Detection and Energy Transfer

Organic linker-based luminescent metal-organic frameworks (LMOFs) have received extensive studies due to the unlimited species of emissive organic linkers and tunable structure of MOFs. However, the multiple-step organic synthesis is always a great challenge for the development of LMOFs. As an alternative strategy, in situ "one-pot" strategy, in which the generation of emissive organic linkers and sequential construction of LMOFs happen in one reaction condition, can avoid time-consuming pre-synthesis of organic linkers. In the present work, we demonstrate the successful utilization of in situ "one-pot" strategy to construct a series of LMOFs via the single-site modification between the reaction of aldehydes and o-phenylenediamine-based tetratopic carboxylic acid. The resultant MOFs possess csq topology with emission covering blue to near-infrared. The nanosized LMOFs exhibit excellent sensitivity and selectivity for tryptophan detection. In addition, two component-based LMOFs can also be prepared via the in situ "one-pot" strategy and used to study energy transfer. This work not only reports the construction of LMOFs with full-color emissions, which can be utilized for various applications, but also indicates that in situ "one-pot" strategy indeed is a useful and powerful method to complement the traditional MOFs construction method for preparing porous materials with tunable functionalities and properties.

Bioinspired Spatial Compartment of Substrate Molecules and Catalytic Counting Entities in Hierarchical MOFs Initiated for a Dual-Mode Glycoprotein Assay

Living cell systems possess multiple isolated compartments that can spatially confine complex substances and shield them from each other to allow for feedback reactions. In this work, a bioinspired design of metal-organic frameworks (MOFs) with well-defined multishelled matrices was fabricated as a hierarchical host for multiple guest substances including fluorogenic molecules and catalytic nanoparticles (NPs) at the separated locations for the development of a dual-mode glycoprotein assay. The multispatial-compartmental zeolitic imidazolate framework-8 (ZIF-8) constituents were synthesized via epitaxial shell-by-shell overgrowth to guide the integration and spatial organization of host guests. The specific property toward glycoprotein recognition was guaranteed by both the antibody-antigen recognition and covalent bonding through boronate-glycan affinity, and the immediate signal responses were initiated by textural collapse of the ZIF-8 integrity. In addition, the inner micropore and the enclosed space of ZIF-8 can avoid the surpassed contact between molecular substances and catalytic entities, inherently. Furthermore, multishelled ZIF-8 can function as a hierarchical matrix for hosting abundant fluorogenic substrates and a large number of catalytic Pt-shelled Au (AuPt) NPs, which can signify its signal amplification means, while upon the stimuli-responsive framework collapse, the signal generators can be harvested in the on-demand manner. Besides, endowing Pt shells on inert plasmonic NPs can not only mimic peroxidase-like catalytic behavior involved in a fluorogenic catalytic reaction to generate fluorescence signals but also function as scattering signal reporters, which can also signify the dynamic light scattering output signals. Collectively, our proposed method may provide a new thought in combining the well-defined multishelled MOF matrices for dual-signal generators in a stimuli-responsive manner, which can also reinforce the accurate detection capability for the glycoprotein assay.

Loading Dyes into Chiral Cd/Zn-Metal-Organic Frameworks for Efficient Full-Color Circularly Polarized Luminescence

Host-guest chemistry of chiral metal-organic frameworks (MOFs) has endowed them with circularly polarized luminescence (CPL), it is still limited for MOFs to systematically tune full-color CPL emissions and sizes. This work directionally assembles the chiral ligands, metal sites and organic dyes to prepare a series of crystalline enantiomeric D/L-Cd/Zn-n MOFs (n=1~5, representing the adding amount of dyes), where D/L-Cd/Zn with the formula of Cd2(D/L-Cam)2(TPyPE) and Zn2(D/L-Cam)2(TPyPE) (D/L-Cam=D/L-camphoric acid, TPyPE=4,4',4'',4'''-(1,2-henediidenetetra-4,1-phenylene)tetrakis[pyridine]) were used as the chiral platforms. The framework-dye-enabled emission and through-space chirality transfer facilitate D/L-Cd/Zn-n bright full-color CPL activity. The ideal yellow CPL of D-Cd-5 and D-Zn-4, with |glum| as 4.9 × 10-3 and 1.3×10-3 and relatively high photoluminescence quantum yield of 40.79 % and 45.40 %, are further assembled into a white CPL light-emitting diode. The crystal sizes of D/L-Cd/Zn-n were found to be strongly correlated to the types and additional amounts of organic dyes, that the positive organic dyes allow for the preparation of > 7 mm bulks and negative dyes account for sub-20 μm particles. This work opens a new avenue to fabricate full-color emissive CPL composites and provides a potentially universal method for controlling the size of optical platforms.

Regulating Planarized Intramolecular Charge Transfer for Efficient Single-Phase White-Light Emission in Undoped Metal-Organic Framework Nanocrystals

The technology of combining multiple emission centers to exploit white-light-emitting (WLE) materials by taking advantage of porous metal-organic frameworks (MOFs) is mature, but preparing undoped WLE MOFs remains a challenge. Herein, a pressure-treated strategy is reported to achieve efficient white photoluminescence (PL) in undoped [Zn(Tdc)(py)]n nanocrystals (NCs) at ambient conditions, where the Commission International del'Eclairage coordinates and color temperature reach (0.31, 0.37) and 6560 K, respectively. The initial [Zn(Tdc)(py)]n NCs exhibit weak-blue PL consisting of localized excited (LE) and planarized intramolecular charge transfer (PLICT) states. After pressure treatment, the emission contributions of LE and PLICT states are balanced by increasing the planarization of subunits, thereby producing white PL. Meanwhile, the reduction of nonradiative decay triggered by the planarized structure results in 5-fold PL enhancement. Phosphor-converted light-emitting diodes based on pressure-treated samples show favorable white-light characteristics. The finding provides a new platform for the development of undoped WLE MOFs.

Highly thermostable RhB@Zr-Eddc for the selective sensing of nitrofurazone and efficient white light emitting diode

Highly thermostable RhB@Zr-Eddc composites with the Rhodamine B (RhB) enclosed into the nanocages of Zr-Eddc was synthesized by one-pot method under hydrothermal conditions, whose structure, morphology and stability were characterized through the X-ray powder diffractometry (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). RhB@Zr-Eddc showed the highly thermal stability up to 550°C and emitted the bright red-light emission at 605 nm, which could highly selective detect the nitrofurazone (NFZ) among eleven other antibiotics in aqueous solution. Furthermore, via combining the RhB@Zr-Eddc with commercial green phosphor (Y3Al5O12:Ce3+, Ga3+), the mixture was encapsulated onto a 455 nm blue LED chip, creating an ex-cellent white light emitting diode (WLED) device with the correlated colour temperature (CCT) of 4710 K, luminous efficiency (LE) of 43.17 lm/w and Color Rendering Index (CRI) of 89.2.

Immobilized Urease Vector System Based on the Dynamic Defect Regeneration Strategy for Efficient Urea Removal

The clearance of urea poses a formidable challenge, and its excessive accumulation can cause various renal diseases. Urease demonstrates remarkable efficacy in eliminating urea, but cannot be reused. This study aimed to develop a composite vector system comprising microcrystalline cellulose (MCC) immobilized with urease and metal-organic framework (MOF) UiO-66-NH2, denoted as MCC@UiO/U, through the dynamic defect generation strategy. By utilizing competitive coordination, effective immobilization of urease into MCC@UiO was achieved for efficient urea removal. Within 2 h, the urea removal efficiency could reach up to 1500 mg/g, surpassing an 80% clearance rate. Furthermore, an 80% clearance rate can also be attained in peritoneal dialyzate from patients. MCC@UiO/U also exhibits an exceptional bioactivity even after undergoing 5 cycles of perfusion, demonstrating remarkable stability and biocompatibility. This innovative approach and methodology provide a novel avenue and a wide range of immobilized enzyme vectors for clinical urea removal and treatment of kidney diseases, presenting immense potential for future clinical applications.

Metal Clusters Confined in Chiral Zeolitic Imidazolate Framework for Circularly Polarized-Luminescence Inks

Chiroptical activities arising in nanoclusters (NCs) are emerging as one of the most dynamic areas of modern science. However, devising an overarching strategy that is capable of concurrently enhancing the photoluminescence (PL) and circularly polarized luminescence (CPL) of metal NCs remains a formidable challenge. Herein, gold and silver nanoclusters (AuNCs, AgNCs) are endowed with CPL, for the first time, through a universal host-guest approach─centered around perturbing a chiral microenvironment within chiral hosts, simultaneously enhancing emissions. Remarkably, the photoluminescence quantum yield (PLQY) of AuNCs has undergone an increase of over 200 times upon confinement, escalating from 0.05% to 12%, and demonstrates a CPL response. Moreover, a three-dimensional (3D) model termed "NCs@CMOF" featuring CPL activity is created using metal cluster-based assembly inks through the process of 3D printing. This work introduces a potentially straightforward and versatile approach for achieving both PL enhancement and CPL activities in metal clusters.

Spatially Resolved Organic Whispering-Gallery-Mode Hetero-Microrings for High-Security Photonic Barcodes

Whispering-gallery-mode (WGM) microcavities featuring distinguishable sharp peaks in a broadband exhibit enormous advantages in the field of miniaturized photonic barcodes. However, such kind of barcodes developed hitherto are primarily based on microcavities wherein multiple gain medias were blended into a single matrix, thus resulting in the limited and indistinguishable coding elements. Here, a surface tension assisted heterogeneous assembly strategy is proposed to construct the spatially resolved WGM hetero-microrings with multiple spatial colors along its circular direction. Through precisely regulating the charge-transfer (CT) strength, full-color microrings covering the entire visible range were effectively acquired, which exhibit a series of sharp and recognizable peaks and allow for the effective construction of high-quality photonic barcodes. Notably, the spatially resolved WGM hetero-microrings with multiple coding elements were finally acquired through heterogeneous nucleation and growth controlled by the directional diffusion between the hetero-emulsion droplets, thus remarkably promoting the security strength and coding capacity of the barcodes. The results would be useful to fabricate new types of organic hierarchical hybrid WGM heterostructures for optical information recording and security labels.

Highly Sensitive Ratiometric Fluorescent Flexible Sensor Based on the RhB@ZIF-8@PVDF Mixed-Matrix Membrane for Broad-Spectrum Antibiotic Detection

Antibiotics play an essential role in the treatment of various diseases. However, the overuse of antibiotics has led to the pollution of water bodies and food safety, affecting human health. Herein, we report a dual-emission MOF-based flexible sensor for the detection of antibiotics in water, which was prepared by first encapsulating rhodamine B (RhB) by a zeolite imidazolium ester skeleton (ZIF-8) and then blending it with polyvinylidene difluoride (PVDF). The luminescent properties, structural tunability, and flexible porosity of the MOF-based composites were combined with the processability and flexibility of polymers to prepare luminescent membranes. The sensor is capable of dual-emission ratiometric fluorescence sensing of nitrofurantoin (NFT) and oxytetracycline (OTC), exhibiting sensitive detection of fluorescence burst and fluorescence enhancement, respectively, with detection limits of 0.012 μM and 8.9 nM. With the advantages of visual detection, high sensitivity, short detection time, and simplicity, the highly sensitive ratiometric fluorescent flexible sensor has great potential for detecting antibiotics in an aqueous environment. It will further stimulate interest in luminescent MOF-based mixed matrix membranes and their sensing applications.

Viologen Guest-Mediated Luminescence Emission Tuning and Photochromic Behavior by a Series of Viologen@Zn-MOF Materials

The encapsulation of various guest molecules into the pores of metal-organic frameworks (MOFs) to form hybrid materials has attracted significant attention due to their unique spatial distribution and certain preferential geometry of the guests inside the MOFs. This arrangement often results in the guests exhibiting unique physical and chemical properties due to their intramolecular interactions with the host. In this article, five viologen derivatives were introduced as guests in a Zn-MOF with different benzene ring lengths, resulting in the formation of host-guest three-dimensional (3D) MOFs. The five compounds exhibited guest-dependent emission wavelength, color, and excellent photochromic behavior upon ultraviolet (UV) light radiation due to the distinct electronic transfer and π···π stacking interactions between the viologen guests and the host framework. This study provides a host-guest strategy for designing color-tunable luminescent and highly sensitive photochromic materials.

Colorimetric Aerogel Gas Sensor with High Sensitivity and Stability

The detection of formic acid vapor in the usage environment is extremely important for human health and safety. The utilization of metal-organic frameworks (MOFs) for the detection of gaseous molecules is an attractive strategy. However, the rational design and construction of MOF-based gas sensors with high sensitivity and mechanical stability remain a significant challenge. In this study, a simple approach is reported to fabricate colorimetric aerogel sensors assembled from MOF particles via ice template-assisted methods. As the aerogel sensor with staggered lamellae structures significantly provides a high air-volume intake of flowing gas, it generates a sufficient probability of contact reactions for highly mobile target molecules. Additionally, it enhances the mechanical stability by providing stress resistance between the staggered lamellae structures. Compared to conventional film sensors for the detection of formic acid molecules, aerogel sensors exhibit an 8-fold lower limit of detection, 15-fold better sensitivity at low concentrations, 34-fold faster response time, and higher stability. This approach shows great potential for rapid and real-time detection of target molecules as well as superior performance in the structural construction of various gas-sensitive materials.

Confinement of Organic Dyes in UiO-66-Type Metal-Organic Frameworks for the Enhanced Synthesis of [1,2,5]Thiadiazole[3,4-g]benzoimidazoles

Organic dyes as non-noble metal photosensitizers have attracted increasing attention due to their environmental friendliness and sustainability but suffer from fast deactivation and low stability. Here, we reported a fruitful strategy by the confinement and stabilization of visible light-active signal unit organic dyes within the metal-organic frameworks (MOFs) and developed a series of heterogeneous photocatalysts dye@UiO-66s [dye = fluorescein (FL)/rhodamine B (RhB)/eosin Y (EY), UiO-66s = UiO-66, and Bim-UiO-66]. It has been demonstrated that the encapsulated dyes can effectively sensitize MOF hosts and dominate the band structures and photocatalytic activities of dye@UiO-66s regardless of the ligand functionalization of MOFs. Photocatalytic experiments showed that these dye@UiO-66s exhibit enhanced activities relative to free dyes and among them, FL@Bim-UiO-66 displays excellent efficiencies toward the green synthesis of new carbon-bridged annulations, [1,2,5]thiadiazole[3,4-g]benzoimidazoles in the yield of up to 98% at room temperature with outstanding stability and reusability. Furthermore, the intramolecular cyclization intermediate was captured and characterized by the single-crystal X-ray diffraction analysis.

Chemorobust dye-encapsulated framework as dual-emission self-calibrating ratiometric sensor for intelligent detection of toluene exposure biomarker in urine

By taking advantages of confinement effect can effectively prevent dye aggregation caused luminescent quenching, Eosin Y (EY) was encapsulated into a chemorobust porous CoMOF as secondary fluorescent signal to construct the dual-emitting sensor of EY@CoMOF. And the photo-induced electron transfer from CoMOF to EY molecules induced EY@CoMOF presenting a weak blue emission at 421 nm and a strong yellow emission at 565 nm. Those dual-emission features also endow EY@CoMOF itself great potentials as a self-calibrating ratiometric sensor in visually and efficiently monitoring hippuric acid (HA) in urine, with fast response, high sensitivity and selectivity, excellent recyclable, and low LOD (0.24 μg/mL). Furthermore, based on a tandem combinational logic gate, an intelligent detection system was designed to improve the practicability and convenience of HA detection in urine. To the best of our knowledge, this is the first example of dye@MOF based sensor for HA detection. And this work provides a promising approach for developing dye@MOF based sensors to intelligent detect bioactive molecules.

Enhanced Luminescence of Dye-Decorated ZIF-8 Composite Films via Controllable D-A Interactions for White Light Emission

Metal-organic frameworks (MOFs) constructed by metal ions/clusters and organic linkers are used to encapsulate fluorescent guest species with aggregation-caused quenching (ACQ) effects to enhance fluorescence properties due to their porous structures and high specific surface areas. However, there would be a problem of matching between MOF pores and guest molecules' sizes. In this paper, amorphous ZIF-8 was modified by carboxyl functional groups (H₃BTC-ZIF-8) via introducing the 1,2,4-benzenetricarbonic acid (H₃BTC) ligand into the ZIF-8 sol system. Moreover, H₃BTC-ZIF-8 was used for the loading of organic fluorescent dyes rhodamine 6G (R6G) and coumarin 151 (C151) to prepare R6G/C151/H₃BTC-ZIF-8 composite films. A white-light-emitting composite film (R6G/C151/H₃BTC-ZIF-8) with CIE coordinates of (0.323, 0.347) was successfully prepared by compounding fluorescent dyes (R6G and C151) with H₃BTC-modified ZIF-8, whose photoluminescence quantum yield (PLQY) can reach 64.0%. It was higher than the PLQY of the composite films prepared by crystalline ZIF-8 (40.2%) or amorphous ZIF-8 without H₃BTC (48.0%) compounded with the same concentrations of dyes. The fluorescence enhancement was probably attributed to an increased amount of active sites of H₃BTC-modified ZIF-8 interacting with dyes C151 and R6G. This can form hydrogen bonds between H₃BTC-ZIF-8 and C151, and weak electron donor-acceptor (D-A) interactions between H₃BTC-ZIF-8 and R6G molecules, respectively, thus enhancing the interactions between dyes and ZIF-8 and reducing the ACQ effect existing between dye molecules. Therefore, this strategy could provide an important guidance to develop white-light-emissive materials.

A novel spectroscopic technique for studying metal-organic frameworks based on Mie scattering

Metal-organic frameworks (MOFs) are promising candidates for a wide range of applications, and spectroscopic techniques are important tools for analyzing their structures and properties. Here, we propose a novel and general scattering spectroscopic approach to study various MOFs such as zeolitic imidazolate frameworks (ZIF-67 and ZIF-8), HKUST-1, Co-based MOF (Co-MOF), and Ni-based MOF (Ni-MOF) based on their inherent Mie scattering properties. We show that by using a dark-field microscope, the inherent scattering colors and spectra can be obtained, which are mainly from the high-order magnetic and electric resonant modes. The scattering capacities are dependent on the chemical structures for producing polarized charges and internal circular displacement currents. Additionally, all the MOFs are capable of responding to solvent guests due to their high porosity, and the scattering peaks are in a linear correlation with solvent refractive indices, displaying scattering solvatochromic behaviors. Our results open up a powerful and universal avenue for visually studying the host-guest interactions in MOFs.

Introduction of Multicomponent Dyes into 2D MOFs: A Strategy to Fabricate White Light-Emitting MOF Composite Nanosheets

Metal-organic frameworks (MOFs) have been extensively studied in host-guest chemistry by means of ultrahigh porosities, tunable channels, and component diversities. As the host matrix, MOFs exhibit immense potential in the preparation of single-phase white light-emitting (SPWLE) materials. Nonetheless, it is a great challenge that the size of the introduced guest molecules is limited by MOF pores, which affects the WLE optimization. In this work, two-dimensional (2D) MOFs are first utilized as the host matrices to simultaneously encapsulate red-green-blue fluorescent dyes for SPWLE. Various dyes@2D MOF composites with high-quality WLE performances and ultrathin nanosheet morphologies are directly assembled from 2D MOF precursors and dyes in high yields. Owing to the flexible interlamellar space of 2D MOFs, different types and sizes of guests can be easily introduced, which greatly expands the range of available MOF hosts and guests, making the WLE much more tunable. The strategy of employing 2D MOFs as the host matrices to introduce multicomponent dyes for SPWLE nanosheets resolves the restriction of MOF pores on the guest molecule size and opens a new avenue to rationally design and prepare SPWLE nanosheets that are highly solution-processable.

Construction of Metal-Organic Framework Films via Crosslinking-Induced Assembly

The construction of metal-organic framework (MOF) films is a crucial step for integrating them into technical applications. However, due to the crystallization nature, it is difficult to grow most MOFs spontaneously or process them into films. Here, a convenient strategy is demonstrated for constructing MOF films by using modulators to achieve homogeneous assembly of MOF clusters. Small clusters in the early growth steps of MOFs can be stabilized by modulators to form fluidic precursors with good processibility. Then, simple removal of modulators will trigger the crosslinking of MOF clusters and lead to the formation of continuous films. This strategy is universal for the fabrication of several types of MOF films with large scale and controllable thickness, which can be deposited on a variety of substrates as well as can be patterned in micro/nano resolution. Additionally, versatile composite MOF films can be easily synthesized by introducing functional materials during the crosslinking process, which brings them broader application prospects.

ZIF-8@Rhodamine B as a Self-Reporting Material for Pollutant Extraction Applications

Herein, we have evaluated the potential of dye-encapsulation as a simple mechanism to self-report the stability of MOFs for pollutant extraction applications. This enabled the visual detection of material stability issues during the selected applications. As proof-of-concept, the zeolitic imidazolate framework (ZIF-8) material was prepared in aqueous medium and at room temperature in the presence of the dye rhodamine B. The total amount of loaded rhodamine B was determined using UV-vis spectrophotometry. The prepared dye-encapsulated ZIF-8 showed a comparable extraction performance with bare ZIF-8 for the removal of hydrophobic endocrine-disrupting phenols, such as 4-tert-octylphenol and 4-nonylphenol, and improved the extraction performance of more hydrophilic endocrine disruptors, such as bisphenol A and 4-tert-butylphenol.

Multi-emitter metal-organic frameworks as ratiometric luminescent sensors for food contamination and spoilage detection

Food contamination and spoilage is a worldwide concern considering its adverse effect on public health and food security. Real time monitoring food quality can reduce the risk of foodborne disease to consumers. Particularly, the emergence of multi-emitter luminescent metal-organic frameworks (LMOFs) as ratiometric sensory materials has provided the possibility for food quality and safety detection with high sensitivity and selectivity taking advantage of specific host-guest interactions, pre-concentrating and molecule-sieving effects of MOFs. Furthermore, the excellent sensing performance of multi-emitter MOF-based ratiometric sensors including self-calibration, multi-dimensional recognition and visual signal readout is able to meet the increasing rigor requirement of food safety evaluation. Multi-emitter MOF-based ratiometric sensors have become the focus of food safety detection. This review focuses on design strategies for different multiple emission sources assembly to construct multi-emitter MOFs materials based on at least two emitting centers. The design strategies for creating multi-emitter MOFs can be mainly classified into three categories: (1) multiple emission building blocks assembly in a single MOF phase; (2) single non-luminescent MOF or LMOF phase as a matrix for chromophore guest(s); (3) heterostructured hybrids of LMOF with other luminescent materials. In addition, the sensing signal output modes of multi-emitter MOF-based ratiometric sensors have critically discussed. Next, we highlight the recent progress for the development of multi-emitter MOF as ratiometric sensors in food contamination and spoilage detection. Their future improvement and advancing direction potential for their practical application is finally discussed.

Energy Transport in Dichroic Metallo-organic Crystals: Selective Inclusion of Spatially Resolved Arrays of Donor and Acceptor Dyes in Different Nanochannels

In this study, the precise positioning and alignment of arrays of two different guest molecules in a crystalline host matrix has been engineered and resulted in new optically active materials. Sub-nm differences in the diameters of two types of 1D channels are sufficient for size-selective inclusion of dyes. Energy transport occurs between the arrays of different dyes that are included in parallel-positioned nanochannels by Förster resonance energy transfer (FRET). The color of individual micro-sized crystals are dependent on their relative position under polarized light. This angular-dependent behavior is a result of the geometrically constrained orientation of the dyes by the crystallographic packing of the host matrix and is concentration dependent.

Recent progress on MOF-based optical sensors for VOC sensing

The raising apprehension of volatile organic compound (VOC) exposures urges the exploration of advanced monitoring platforms. Metal-organic frameworks (MOFs) provide many attractive features including tailorable porosity, high surface areas, good chemical/thermal stability, and various host-guest interactions, making them appealing candidates for VOC capture and sensing. To comprehensively exploit the potential of MOFs as sensing materials, great efforts have been dedicated to the shaping and patterning of MOFs for next-level device integration. Among different types of sensors (chemiresistive sensors, gravimetric sensors, optical sensors, etc.), MOFs coupled with optical sensors feature distinctive strength. This review summarized the latest advancements in MOF-based optical sensors with a particular focus on VOC sensing. The subject is discussed by different mechanisms: colorimetry, luminescence, and sensors based on optical index modulations. Critical analysis for each system highlighting practical aspects was also deliberated.

Zoledronate combined metal-organic frameworks for bone-targeting and drugs deliveries

Medicine treatments for bone-related diseases such as osteoporosis, bone metastasis, osteomyelitis, and osteolysis are often limited by insufficient drug concentration at the lesion sites owing to the low perfusion of bone tissue. A carrier that can deliver multiple bone destruction site-targeting drugs is required to address this limitation. Here, we reported a novel bone-targeting nano-drug delivery platform formed by the integration of zoledronate (ZOL) and zeolitic imidazolate framework-8 (ZIF-8) nanoparticles. The ZOL mixed zeolitic imidazolate framework (ZZF) nanoparticles were synthesized in water at room temperature (25 °C), where many biomacromolecules could maintain their activity. This allowed the ZZF nanoparticles to adapt the encapsulation ability and pH response release property from ZIF-8 and the excellent bone targeting performance of ZOL simultaneously. Considering the ease of preparation and biomacromolecule-friendly drug delivery of this nano platform, it may be useful in treating bone-related diseases.

Tunable fluorescence emission based on multi-layered MOF-on-MOF

Luminescent metal-organic frameworks (MOFs) have garnered considerable attention in various fields. Herein, we proposed a hierarchical confinement strategy based on MOF-on-MOF to tune luminescence emission ranging from blue to red including white light in a flexible way. The easily available ZIF-8 MOF was used as a host for the confinement of two kinds of size-matching dyes (perylene and rhodamine B) to obtain a layered ZIF-8@dye@ZIF-8@dye via in situ encapsulation and seed-mediated synthesis. ZIF-8@dye@ZIF-8@dye materials with different fluorescence emission in dispersed and solid states were both obtained by tuning the initial encapsulation concentration of dye and changing the structure of the inner and outer ZIF-8@dye layers. To our delight, ZIF-8@0.125perylene@ZIF-8@25RhB with white light emission in the dispersed state was obtained; meanwhile, ZIF-8@0.125perylene + 25RhB and mechanically mixed ZIF-8@0.125perylene + ZIF-8@25RhB could not realize white light emission under the same conditions, indicating that the proposed hierarchical confinement strategy facilitated white light regulation. Similarly, the emission of ZIF-8@dye@ZIF-8@dye in the solid state has also been investigated; ZIF-8@perylene@ZIF-8@3RhB with white light emission was obtained, while white light emission could not be achieved in ZIF-8@perylene + 3RhB and ZIF-8@perylene + ZIF-8@3RhB, which further indicated the importance of the hierarchical confinement strategy based on MOF-on-MOF. The proposed hierarchical confinement strategy may also inspire the development of other functional optical MOF materials.

Confinement of Luminescent Guests in Metal-Organic Frameworks: Understanding Pathways from Synthesis and Multimodal Characterization to Potential Applications of LG@MOF Systems

This review gives an authoritative, critical, and accessible overview of an emergent class of fluorescent materials termed "LG@MOF", engineered from the nanoscale confinement of luminescent guests (LG) in a metal-organic framework (MOF) host, realizing a myriad of unconventional materials with fascinating photophysical and photochemical properties. We begin by summarizing the synthetic methodologies and design guidelines for representative LG@MOF systems, where the major types of fluorescent guest encompass organic dyes, metal ions, metal complexes, metal nanoclusters, quantum dots, and hybrid perovskites. Subsequently, we discuss the methods for characterizing the resultant guest-host structures, guest loading, photophysical properties, and review local-scale techniques recently employed to elucidate guest positions. A special emphasis is paid to the pros and cons of the various methods in the context of LG@MOF. In the following section, we provide a brief tutorial on the basic guest-host phenomena, focusing on the excited state events and nanoscale confinement effects underpinning the exceptional behavior of LG@MOF systems. The review finally culminates in the most striking applications of LG@MOF materials, particularly the "turn-on" type fluorochromic chemo- and mechano-sensors, noninvasive thermometry and optical pH sensors, electroluminescence, and innovative security devices. This review offers a comprehensive coverage of general interest to the multidisciplinary materials community to stimulate frontier research in the vibrant sector of light-emitting MOF composite systems.

Color tunable of Ln-MOFs (Ln = Tb, Eu) and excellent stability for white light-emitting diode

White light-emitting diodes (WLEDs) possess the advantages of environmental friendliness, long lifetime, and energy saving. Recently, metal-organic frameworks (MOFs) have become one of the hot candidates for LEDs. However, the tunable color and thermal stability of MOFs are urgent problems for their actual applications. In this work, Ln-MOFs (Ln = Eu, Tb) were synthesized by a facile wet chemical route. A series of Ln-MOFs phosphors with tunable luminescence color showed potential applications in white LEDs. The emission color of the phosphors can be easily modulated by changing the molar ratio of the raw materials. The luminescence intensities of Ln-MOFs retained over 90.6% of the initial value, showing excellent thermal stability of Ln-MOFs. In order to explore the potential applications of Ln-MOFs in WLEDs, we mixed them with two kinds of blue phosphors and packaged them to obtain WLEDs. The CIE coordinates of both were (0.31, 0.33) and (0.31, 0.34), which were able to achieve white light emission. The peak shape and peak position in the EL spectrum of the WLEDs device remained stable when increasing the applied current of the device. Meanwhile, the white light with excellent color quality and visual performance was achieved. The results show that Ln-MOFs are potential materials for white light LED, and provide a novel idea for the application of Ln-MOFs materials in the luminescence field.

Monosystem Discriminative Sensor toward Inorganic Anions via Incorporating Three Different Luminescent Channels in Metal-Organic Frameworks

Because there are great demands of distinguishing multiple chemically similar analytes, chemical sensors for multivariate analyses have been developed rapidly in the past few decades. However, designing luminescent discriminative sensors based on a monosystem has been a challenge until now. In this work, we first develop a triemitting luminescent discriminative platform named RGB@TLU-2 with three different emission centers: blue-emitting center (BDC-NH₂), green-emitting (Tb@BDC-SO₃^-), and red-emitting center (rhodamine B, RhB). The different luminescent mechanisms (ligand emission, LMET emission, guest emission) in these emission centers endow RGB@TLU-2 with high cross-reactivity, which is essential for discriminating applications. To balance the three luminescent centers, all variables in the synthesis process are optimized carefully. Surprisingly, the RGB@TLU-2 shows a variety of luminescent response patterns when immersed into 12 inorganic anions. Two unsupervised multidimensional analysis methods, (principal component analysis and hierarchical cluster analysis), are used to explore the relationship between these anions. On the basis of the luminescent response of analytes, 5 response modes are obtained and 12 inorganic anions are classified into 6 groups. The sensing mechanisms are discussed in detail. Detection limits of typical anions Cr₂O₇^2-, PO₄^3-, ClO^-, and NO₂^- are calculated as 2.895 × 10^-8, 6.353 × 10^-6, 1.134 × 10^-5, and 4.56 × 10^-4 mol/L, respectively. Furthermore, the RGB@TLU-2 also shows the ability to distinguish 4 (Fe³⁺, Fe²⁺, Cu²⁺ and Cr³⁺) of 12 metal ions and 3 (Trp, Pro, and Arg) of 11 amino acids.

Multi-Emission from Single Metal-Organic Frameworks under Single Excitation

Multi-emission materials have come to prominent attention ascribed to their extended applications other than single-emission ones. General and robust design strategies of a single matrix with multi-emission under single excitation are urgently required. Metal-organic frameworks (MOFs) are porous materials prepared with organic ligands and metal nodes. The variety of metal nodes and ligands makes MOFs with great superiority as multi-emission matrices. Guest species encapsulated into the channels or pores of MOFs are the additional emission sites for multi-emission. In this review, multi-emission MOFs according to the different excitation sites are summarized and classified. The emission mechanisms are discussed, such as antenna effect, excited-state intramolecular proton transfer (ESIPT) and tautomerism for dual-emission. The factors that affect the emissions are revealed, including ligand-metal energy transfer and host-guest interaction, etc. Multi-emission MOFs could be predictably designed and prepared, once the emissive factors are controlled rationally in combination with the different multi-emission mechanisms. Correspondingly, new and practical applications are realized, including but not limited to ratiometric/multi-target sensing and bioimaging, white light-emitting diodes, and anti-counterfeiting. The design strategies of multi-emission MOFs and their extensive applications are reviewed. The results will shed light on other multi-emission systems to develop the structure-derived functionality and applications.

Construction and Sensing Amplification of Raspberry-Shaped MOF@MOF

MOFs@MOFs (metal-organic frameworks, MOFs) possess precise customized functionalities and predesigned structures that enable the implementation of structure and property regulation for specific functions in comparison to traditional single MOFs. However, the synthesis and fluorescence properties of multilayer MOFs@MOFs are still worth improving. Herein, a fluorescent raspberry-shaped MOF@MOF was constructed via optimized seed-mediated synthesis by tuning the reaction time, reaction mode, and reaction concentration, involving the initial synthesis of the UiO-66-NH₂ core and then the coating of the UiO-67-bpy shell. The raspberry-shaped UiO-66@67-bpy showed stable fluorescence and desirable sensing selectivity for the Hg²⁺ ion under the interference of other ions; meanwhile, the raspberry-shaped UiO-66@67-bpy indicated amplified sensing performance than pure UiO-66-NH₂, mechanically mixed UiO-66-NH₂ + UiO-67-bpy, and UiO-66@UiO-67 counterpart due to the accumulation effect of outer UiO-67-bpy toward Hg²⁺. Density functional theory (DFT) calculations including adsorption energy calculations and electronic density difference analysis further showed that the enhanced fluorescence quenching was possibly attributed to the outer UiO-67-bpy enrichment promoting the charge transfer between Hg²⁺ and the ligands of fluorescent UiO-66@67-bpy. The synergistic effect of MOFs@MOFs unlocks more possibilities for the construction of enhanced sensors and other applications.

Magnetooptical Properties of Lanthanide(III) Metal-Organic Frameworks Based on an Iridium(III) Metalloligand

Integrating magnetic and optical properties into a metal-organic framework (MOF) remains a great challenge. Herein, we have reasonably constructed two 3D magnetooptical MOFs by incorporating a [Ir^III(ppy)₂(bpy)]⁺-based fluorescent metalloligand and magnetic Ln^III centers. The alternating arrangements of Δ- or Λ-[Ir^III(ppy)₂(bpy)]⁺ endow these MOFs with enhanced optical properties. Moreover, the use of Dy^III leads to field-induced slow magnetic relaxation. This work provides an effective strategy for the preparation of magnetooptical bifunctional MOFs.

Hierarchically encapsulating enzymes with multi-shelled metal-organic frameworks for tandem biocatalytic reactions

Biocatalytic transformations in living organisms, such as multi-enzyme catalytic cascades, proceed in different cellular membrane-compartmentalized organelles with high efficiency. Nevertheless, it remains challenging to mimicking biocatalytic cascade processes in natural systems. Herein, we demonstrate that multi-shelled metal-organic frameworks (MOFs) can be used as a hierarchical scaffold to spatially organize enzymes on nanoscale to enhance cascade catalytic efficiency. Encapsulating multi-enzymes with multi-shelled MOFs by epitaxial shell-by-shell overgrowth leads to 5.8~13.5-fold enhancements in catalytic efficiencies compared with free enzymes in solution. Importantly, multi-shelled MOFs can act as a multi-spatial-compartmental nanoreactor that allows physically compartmentalize multiple enzymes in a single MOF nanoparticle for operating incompatible tandem biocatalytic reaction in one pot. Additionally, we use nanoscale Fourier transform infrared (nano-FTIR) spectroscopy to resolve nanoscale heterogeneity of vibrational activity associated to enzymes encapsulated in multi-shelled MOFs. Furthermore, multi-shelled MOFs enable facile control of multi-enzyme positions according to specific tandem reaction routes, in which close positioning of enzyme-1-loaded and enzyme-2-loaded shells along the inner-to-outer shells could effectively facilitate mass transportation to promote efficient tandem biocatalytic reaction. This work is anticipated to shed new light on designing efficient multi-enzyme catalytic cascades to encourage applications in many chemical and pharmaceutical industrial processes.

Mimicking multi-enzyme catalytic cascades in natural systems with spatial organization in confined structures is gaining increasing attention in the emerging field of systems chemistry. Here, the authors demonstrate that multi-shelled metal-organic frameworks can be used as a hierarchical scaffold to spatially organize enzymes on nanoscale to enhance cascade catalytic efficiency.

Functionalization of a stable AIE-based hydrogen-bonded organic framework for white light-emitting diodes

Hydrogen-bonded organic frameworks (HOFs) have received tremendous attention in recent years due to the good designability. However, the pure organic nature of HOFs sometimes limits the application development and performance improvement. Functionalizing is an effective strategy to control and modulate material properties, which can achieve properties that cannot be achieved by a pristine material. Herein, a series of HOF-76⊃DSMI were synthesized through functionalizing the stable AIE-based HOF-76 by incorporating a red dye which complements the deficiency of the red component of HOF-76. Then, a single matrix white light-emitting diode (WLED) was fabricated by coating the HOF-76⊃DSMI material on a 460 nm blue LED with CIE chromaticity coordinates of (0.333, 0.329), a correlated colour temperature (CCT) of 5490 K and a colour rendering index (CRI) of 80.

We successfully fabricated a white light-emitting diode by coating functionalized AIE-based HOF-76 material on a 460 nm blue LED chip.

Luminescent MOFs (LMOFs): Recent Advancement Towards a Greener WLED Technology

The replacement of the traditional incandescent, halogen and fluorescent lamps by white light emitting diodes (WLEDs) is expected to reduce the global electricity consumption by one-third by 2030, according to...

Tandem Förster resonance energy transfer induced visual ratiometric fluorescence sensing of tetracyclines based on zeolitic imidazolate framework-8 incorporated with carbon dots and safranine T

With increasing TC concentration, tandem FRET1 from CDs to TC, then FRET2 from TC to safranine T were occurred. TC could be easily recognized by naked eye. Besides, we could perform on-site detection of TC with the help of a mobile phone.

Amino Group Induced Structural Diversity and Near-Infrared Emission of Yttrium-Tetracarboxylate Frameworks

Near-infrared (NIR)-emitting materials have been extensively studied due to their important applications in biosensing and bioimaging. Luminescent metal–organic frameworks (LMOFs) are a new class of highly emissive materials with strong potential for utilization in biomedical related fields because of their nearly unlimited structural and compositional tunability. However, very little work has been reported on organic linker-based NIR-MOFs and their emission properties. In the present work, a series of yttrium-tetracarboxylate-based LMOFs (HIAM-390X) are prepared via judicious linker design to achieve NIR emission with diverse structures. The introduction of an amino group not only offers the remarkable emission bathochromic shift from 521 nm, 665 nm to 689 nm for the resultant MOFs, but also influences the linker conformations, leading to the topology evolution from (4,12)-c ftw, (4,8)-c scu, which is rarely reported in rare earth element-based MOFs, to an unprecedented topology hlx for HIAM-3901 (without an amino group), HIAM-3905 (with one amino group) and HIAM-3906 (with two amino groups). Among these MOFs, HIAM-3907 shows an emission maximum at ∼790 nm, with the emission tail close to 1000 nm. The NIR emission may be attributed to the combination of the strongly electron-donating amino group and the strongly electron-withdrawing acceptor naphtho[2,3-c][1,2,5]selenadiazole. This work sheds light on the rational design of organic linker-based LMOFs with controlled structures and NIR emission, and inspires future interest in biosensing and bioimaging related applications of NIR-MOFs.

Introduction of amino groups into linkers will not only induce a significant emission red-shift to near-infrared, but also increase structural diversity of resultant LMOFs, leading to structural change from ftw, scu to an unprecedented topology hlx.

Full-Color Emission in Multicomponent Metal-Organic Frameworks via Linker Installation

Herein, we demonstrate that linker installation (LI) through postsynthesis is an effective strategy to insert emissive second linkers into single-linker-based metal-organic frameworks (MOFs) to tune the emission properties of multicomponent MOFs. Full-color emission, including white-light emission, can be achieved via such a LI process.

A Luminescent Guest@MOF Nanoconfined Composite System for Solid-State Lighting

A series of rhodamine B (RhB) encapsulated zeolitic imidazolate framework-8 (RhB@ZIF-8) composite nanomaterials with different concentrations of guest loadings have been synthesized and characterized in order to investigate their applicability to solid-state white-light-emitting diodes (WLEDs). The nanoconfinement of the rhodamine B dye (guest) in the sodalite cages of ZIF-8 (host) is supported by fluorescence spectroscopic and photodynamic lifetime data. The quantum yield (QY) of the luminescent RhB@ZIF-8 material approaches unity when the guest loading is controlled at a low level: 1 RhB guest per ~7250 cages. We show that the hybrid (luminescent guest) LG@MOF material, obtained by mechanically mixing a suitably high-QY RhB@ZIF-8 red emitter with a green-emitting fluorescein@ZIF-8 “phosphor” with a comparably high QY, could yield a stable, intensity tunable, near-white light emission under specific test conditions described. Our results demonstrate a novel LG@MOF composite system exhibiting a good combination of photophysical properties and photostability, for potential applications in WLEDs, photoswitches, bioimaging and fluorescent sensors.

Excited State Energy Transfer in Metal-Organic Frameworks

Excited state energy transfer in metal-organic frameworks (MOFs) is of great interest due to potential application of these materials in photocatalysis and fluorescence sensing. In photocatalysis, a light-harvesting antenna of MOFs can collect energy from a much larger area than a single reaction center and efficiently transport the energy to the active site to enhance photocatalytic efficiency, mimicking nature photosynthesis. In fluorescence sensing, excited state traveling on the framework can search for analyte quencher molecules to give amplified fluorescence quenching, so that one quencher turns off multiple excited states to enhance signal. Key to these designer performances is highly efficient energy transfer on these framework materials that are determined by types of excited states, dimension of the materials, and structure of the frameworks. Advancement of MOF synthetic chemistry provides new tools to control the rate and directionality of energy transfer in these materials, opening opportunities in manipulating excited states at an unprecedented level.

Luminescent Metal-Phenolic Networks for Multicolor Particle Labeling

The development of fluorescence labeling techniques has attracted widespread interest in various fields, including biomedical science as it can facilitate high-resolution imaging and the spatiotemporal understanding of various biological processes. We report a supramolecular fluorescence labeling strategy using luminescent metal-phenolic networks (MPNs) constructed from metal ions, phenolic ligands, and common and commercially available dyes. The rapid labeling process (<5 min) produces ultrathin coatings (≈10 nm) on diverse particles (e.g., organic, inorganic, and biological entities) with customized luminescence (e.g., red, blue, multichromatic, and white light) simply through the selection of fluorophores. The fluorescent coatings are stable at pH values from 1 to 8 and in complex biological media owing to the dominant π interactions between the dyes and MPNs. These coatings exhibit negligible cytotoxicity and their strong fluorescence is retained even when internalized into intracellular compartments. This strategy is expected to provide a versatile approach for fluorescence labeling with potential in diverse fields across the physical and life sciences.

Flexible Zn-MOF with Rare Underlying scu Topology for Effective Separation of C6 Alkane Isomers

Adsorptive separation by porous solids provides an energy-efficient alternative for the purification of important chemical species compared to energy-intensive distillations. Particularly, the separation of linear hexane isomers from its branched counterparts is crucial to produce premium grade gasoline with high research octane number (RON). Herein, we report the synthesis of a new, flexible zinc-based metal-organic framework, [Zn5(μ3-OH)2(adtb)2(H2O)5·5 DMA] (Zn-adtb), constructed from a butterfly shaped carboxylate linker with underlying (4,8)-connected scu topology capable of separating the C6 isomers nHEX, 3MP, and 23DMB. The sorbate-sorbent interactions and separation mechanisms were investigated and analyzed through in situ FTIR, solid state NMR measurements and computational modeling. These studies reveal that Zn-adtb discriminates the nHEX/3MP isomer pair through a kinetic separation mechanism and the nHEX/23DMB isomer pair through a molecular sieving mechanism. Column breakthrough measurements further demonstrate the efficient separation of linear nHEX from the mono- and dibranched isomers.

Tailoring Heterogeneous Catalysts at the Atomic Level: In Memoriam, Prof. Chia-Kuang (Frank) Tsung

Professor Chia-Kuang (Frank) Tsung made his scientific impact primarily through the atomic-level design of nanoscale materials for application in heterogeneous catalysis. He approached this challenge from two directions: above and below the material surface. Below the surface, Prof. Tsung synthesized finely controlled nanoparticles, primarily of noble metals and metal oxides, tailoring their composition and surface structure for efficient catalysis. Above the surface, he was among the first to leverage the tunability and stability of metal-organic frameworks (MOFs) to improve heterogeneous, molecular, and biocatalysts. This article, written by his former students, seeks first to commemorate Prof. Tsung's scientific accomplishments in three parts: (1) rationally designing nanocrystal surfaces to promote catalytic activity; (2) encapsulating nanocrystals in MOFs to improve catalyst selectivity; and (3) tuning the host-guest interaction between MOFs and guest molecules to inhibit catalyst degradation. The subsequent discussion focuses on building on the foundation laid by Prof. Tsung and on his considerable influence on his former group members and collaborators, both inside and outside of the lab.

Encapsulation of Dyes in Luminescent Metal-Organic Frameworks for White Light Emitting Diodes

The development of white light emitting diodes (WLEDs) holds great promise for replacing traditional lighting devices due to high efficiency, low energy consumption and long lifetime. Metal-organic frameworks (MOFs) with a wide range of luminescent behaviors are ideal candidates to produce white light emission in the phosphor-converted WLEDs. Encapsulation of emissive organic dyes is a simple way to obtain luminescent MOFs. In this review, we summarize the recent progress on the design and constructions of dye encapsulated luminescent MOFs phosphors. Different strategies are highlighted where white light emitting phosphors were obtained by combining fluorescent dyes with metal ions and linkers.