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Showing papers in "CrystEngComm in 2016"


Journal ArticleDOI
TL;DR: In this paper, the authors summarize the progress in recent research in NACs sensing based on LMOFs cataloged by sensing techniques in the past three years, and then they describe the sensing applications for nano-MOF type materials and MOF film, together with MOF films applications.
Abstract: Metal–organic frameworks (MOFs), composed of organic ligands and metal nodes, are well known for their high and permanent porosity, crystalline nature and versatile potential applications, which promoted them to be one of the most rapidly developing research focuses in chemical and materials science. During the various applications of MOFs, the photoluminescence properties of MOFs have received growing attention, especially for nitroaromatics (NACs) sensing, due to the consideration of homeland security, environmental cleaning and military issues. In this highlight, we summarize the progress in recent research in NACs sensing based on LMOFs cataloged by sensing techniques in the past three years, and then we describe the sensing applications for nano-MOF type materials and MOF film, together with MOF film applications.

230 citations


Journal ArticleDOI
TL;DR: In this paper, the authors present recent developments in the area of metal-organic frameworks (MOFs) for aqueous phase TNP sensing and discuss strategies used to improve the sensing performance.
Abstract: 2,4,6-Trinitrophenol (TNP) is a highly explosive molecule that is also widely used in industrial processing on a large scale. During synthesis, processing and disposal, TNP is released to the environment especially to water streams, contaminating ground and surface water. TNP and its biologically transformed products like picramic acids have been identified as highly toxic species to biota and may lead to chronic diseases such as sycosis and cancer. Thus, aqueous phase detection of TNP becomes an imperative aspect for the design of any potential sensor. Metal–organic frameworks (MOFs) have emerged as an important class of sensors owing to their permanent porosity, designability and variety of signal transduction pathways. Luminescent MOFs (LMOFs) have shown great potential as sensors for various nitro explosives by modulation of their luminescence behaviour in the presence of nitro explosives. Most of the LMOFs detect nitro explosives in the vapour phase and/or in organic solvents while aqueous phase detection is rarely investigated. Herein we present recent developments in the area of LMOFs for aqueous phase TNP sensing and discuss strategies used to improve the sensing performance. Finally, based on our perspective, important aspects of LMOF performance needing immediate attention for future developments are provided.

175 citations


Journal ArticleDOI
TL;DR: The remarkable properties of graphene have inspired great research interest in two-dimensional layered materials (2DLMs) with novel electronic and optical attributes as mentioned in this paper, which have shown great potential in electronics and optoelectronics.
Abstract: The remarkable properties of graphene have inspired great research interest in two-dimensional layered materials (2DLMs) with novel electronic and optical attributes. As a class of graphene-like 2DLMs, ultrathin group IIIA metal chalcogenides (GIIIAMCs, metal = In, Ga; chalcogen = S, Se, Te) have shown great potential in electronics and optoelectronics. In this review, we first introduce the crystal structures and their unique advantages in specific potential applications. Then, we summarize the progress in the fabrication of GIIIAMCs in the framework of top-down and bottom-up methods. Next, their recent achievements regarding enhanced field-effect transistor and photodetector applications are discussed in detail. In addition, the construction strategies of hybrid GIIIAMCs heterostructures and their applications in electronics and optoelectronics are presented. Finally, this review is concluded with some perspectives and an outlook for continued research.

168 citations


Journal ArticleDOI
TL;DR: In this article, the crystal growth mechanism of zeolites was reviewed and some of the latest findings in this field were discussed, with the overall aim of increasing control over the zeolite properties and structure.
Abstract: This paper will review the crystal growth mechanism of zeolites and discuss some of the latest findings in this field. A great effort has been dedicated in recent years to improving the fundamental understanding of zeolite crystal growth during the synthesis process, with the overall aim of increasing control over the zeolite properties and structure. The latest studies on zeolite crystallization in colloidal (clear) suspensions, prepared by addition of organic and inorganic structural directing agents, in comparison to traditional gel synthesis and seed-approach will be discussed. Further understanding of the imperative dependence of zeolite crystallization kinetics' on the nature and mode of mixing of the initial reactants, leading to the formation of amorphous particles, intermediates, and final crystalline zeolites will be presented.

153 citations


Journal ArticleDOI
TL;DR: A comprehensive review on luminescent MOFs as sensory materials for diverse sensing applications including for metal ions, anions, small molecules and gases, nitroaromatics and explosives, temperature, as well as other aspects is provided in this article.
Abstract: Metal–organic frameworks (MOFs), self-assembled from metal ions with organic ligands, are well known for their intriguing framework topology, permanent porosity, and tunable optical properties and have shown great promise for a good number of applications. Over the past few years, luminescent MOFs have attracted growing attention, especially for developing various luminescent sensors, by virtue of their excellent selectivity and high sensitivity. In this feature article, we highlight some of the recent significant progress in this active research field, and provide a comprehensive review on luminescent MOFs as sensory materials for diverse sensing applications including for metal ions, anions, small molecules and gases, nitroaromatics and explosives, temperature, as well as other aspects.

151 citations


Journal ArticleDOI
TL;DR: In this paper, the authors highlight the recent advances on the thermally-induced structural phase transitions of the perovskite compounds based on the diatomic or multiatomic bridges, focusing on the important role of the components in the phase transition behaviours as well as the intrinsic switching behaviours of physical properties.
Abstract: The structural phase transitions in perovskite compounds were revived in the past decade by the emergence of a large number of perovskite compounds based on diatomic or multiatomic bridges, e.g. CN−, N3−, HCOO−, SCN−, and N(CN)2−, with various interesting properties for possible applications such as in dielectric switches, ferroelectrics, and multiferroics. Compared with the well-studied perovskite oxides and halides, these new perovskite compounds with larger bridges give rise to an increase in the complexity of structural variations as well as an opportunity to tailor the physical properties by taking advantage of the designable and tunable characteristics of the metal species, bridging ligands, and guest cation components. Here, we highlight the recent advances on the thermally-induced structural phase transitions of the perovskite compounds based on the diatomic or multiatomic bridges, focusing on the important role of the components in the phase transition behaviours as well as the intrinsic switching behaviours of physical properties.

134 citations


Journal ArticleDOI
TL;DR: Amorphous, pseudohexagonal and orthorhombic Nb2O5 nanoparticles were synthesized using a facile and green sol-gel process followed by thermal treatment at 450 °C, 600 °C and 800 °C for 3 h in air, respectively as mentioned in this paper.
Abstract: Amorphous, pseudohexagonal and orthorhombic Nb2O5 nanoparticles were synthesized using a facile and green sol–gel process followed by thermal treatment at 450 °C, 600 °C and 800 °C for 3 h in air, respectively. The resulting materials have been subjected to a detailed experimental study and comparison of their structural, electrical and electrochemical properties. The experiments have demonstrated that the pseudohexagonal Nb2O5 (TT-Nb2O5) exhibited higher storage capacity, largely due to its high specific surface area and small crystallites, and better cycling performance than both amorphous Nb2O5 (a-Nb2O5) and orthorhombic Nb2O5 (T-Nb2O5); such experimental findings were found to be associated with and thus ascribed to the lower charge transfer resistance and higher lithium ion diffusion coefficient of TT-Nb2O5 than those of a-Nb2O5 and T-Nb2O5. This research contributes to a better fundamental understanding of the relationship between the crystal structure and the crystallinity and electrochemical properties, particularly Li-ion storage properties, and leads to a possible new advancement in the research field of lithium ion batteries and pseudocapacitors.

131 citations


Journal ArticleDOI
TL;DR: Co-crystallization is the supramolecular phenomenon of aggregation of two or more different chemical entities in a crystalline lattice through non-covalent interactions.
Abstract: Co-crystallization is the supramolecular phenomenon of aggregation of two or more different chemical entities in a crystalline lattice through non-covalent interactions. It encompasses the study of the manifestation of multi-component crystalline solids as well as their design. The chemistry community and the literature suggest cocrystals with reference to co-crystallization products and multi-component crystalline solids. Over the last decade cocrystals have become very popular as a potential new/alternate solid form of pharmaceuticals. However, there is no consensus on what exactly a cocrystal means and what it constitutes across academia, industry and regulatory bodies. On the other hand, cocrystals have been endorsed to the extent that the following facts have been obscured: (1) cocrystals are only one of the putative outcomes of co-crystallization, if at all, and (2) their application goes way beyond pharmaceuticals. Solvates, solid solutions, eutectics, salts, ionic liquids, solid dispersions, supramolecular gelators etc. are among the multifarious products of co-crystallization. The manifestation of these supramolecular/non-covalent crystalline adducts is controlled by the inherent nature of the system (the components involved) besides the surroundings (temperature, solvent, pH etc.); in effect it is a thermodynamic outcome. Each of these adducts, including cocrystals, are unique, exhibit varied physicochemical properties and are amenable to design and therefore have, and potentially find, manifold applications in diverse fields such as organic synthesis & separation, green chemistry, energy storage, solar cells, electronics, luminescent and smart materials, apart from pharmaceuticals. This article highlights the diversity of crystal forms and the utility of small molecule supramolecular combinations.

130 citations


Journal ArticleDOI
TL;DR: In this article, a new strongly luminescent Zr(IV)-based metal-organic framework (MOF) material was synthesized under solvothermal conditions (150 °C, 24 h) using ZrCl4 and the H2BTDB ligand in DMF.
Abstract: A new, strongly luminescent Zr(IV)-based metal–organic framework (MOF) material (1) having a UiO-68 (UiO = University of Oslo) framework topology and incorporating the π-conjugated, thiadiazole-functionalized H2BTDB {H2BTDB = 4,4′-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dibenzoic acid} ligand was synthesized under solvothermal conditions (150 °C, 24 h) using ZrCl4 and the H2BTDB ligand in DMF (DMF = N,N-dimethylformamide). The phase-purity of as-synthesized 1 was ascertained by X-ray powder diffraction (XRPD) analysis, Fourier transform infrared (FT-IR) spectroscopy and elemental analysis. Based on the thermogravimetric analyses, 1 is thermally stable up to 400 °C. XRPD experiments verify that activated 1′ retains its crystallinity when exposed to water, acetic acid and 1 M HCl solutions. As revealed by the steady-state fluorescence titration experiments, the thermally activated form of the compound (1′) showed a selective sensing behaviour towards 2,4,6-trinitrophenol (TNP, commonly known as picric acid), even in the presence of other potentially competing nitroaromatic explosive compounds. The estimated detection limit of 1′ for sensing TNP in methanol suspension was found to be 1.63 × 10−6 M. The highest fluorescence quenching ability of TNP can be attributed to both energy and electron transfer processes as well as electrostatic interactions between the hydroxyl group of TNP and the Lewis basic N-donor sites of the BTDB ligand. Endowed with its excellent detection efficiency, 1′ is a promising luminescent sensor material for the long-term, practical sensing of TNP.

129 citations


Journal ArticleDOI
Chun-Shuai Cao1, Huan-Cheng Hu1, Hang Xu1, Wan-Zhen Qiao1, Bin Zhao1 
TL;DR: Two unique 2D Zn-MOFs with the formulas {[Zn(btz)]n} (1) and {Zn2(ttz)H2O]n}(2) were synthesized using in situ generated ligands under hydro(solvo)thermal conditions as mentioned in this paper.
Abstract: Two unique 2D Zn-MOFs with the formulas {[Zn(btz)]n} (1) and {[Zn2(ttz)H2O]n} (2) were synthesized using in situ generated ligands under hydro(solvo)thermal conditions. Both 1 and 2 exhibit high thermo-stability, solvent-stability and pH-stability. Thermogravimetric analyses (TGA) reveal that 1 and 2 remain intact until about 365 °C and 332 °C, respectively. The samples of 1 and 2 were immersed in twelve common solvents for 24 hours, and the obtained PXRD patterns remain well consistent with the simulated ones. They were immersed in a series of solutions with pH values ranging from 1.0 to 14.0 for five hours, and the PXRD patterns of these samples remain unchanged spanning the pH range of 1–13. The luminescence investigations reveal that the compounds 1 and 2 can efficiently and selectively detect Cr2O72− or CrO42− among twenty-one anions. Importantly, they can be regenerated by a fast and simple method in detecting Cr2O72− or CrO42−.

123 citations


Journal ArticleDOI
TL;DR: In this paper, some emerging topics in the field of metal-organic frameworks (MOF) have been discussed, which show promise for new applications in areas such as biotechnology, catalysis, and microelectronics.
Abstract: Metal–organic frameworks are a unique class of materials well known for their crystallinity and ultra-high porosity. Since their first report over fifteen years ago, research in this area has sought to actively exploit these properties, especially in gas adsorption. In this article we canvass some emerging topics in the field of MOF research that show promise for new applications in areas such as biotechnology, catalysis, and microelectronics.

Journal ArticleDOI
TL;DR: In this article, the authors highlight porphyrinic metal-organic frameworks (porph-MOFs) assembled from metal ions and custom-designed porphrin-based bridging ligands.
Abstract: This paper highlights porphyrinic metal–organic frameworks (porph-MOFs) assembled from metal ions and custom-designed porphyrins. The contents are divided into three sections based on the types of polytopic porphyrin bridging ligands in porph-MOFs: (1) porph-MOFs containing 5,10,15,20-tetra(4-pyridyl)porphyrinato (TPyP) ligand and other pyridyl-based porphyrin bridging ligands, (2) porph-MOFs containing 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrinato (TCPP) ligand and other carboxyphenyl-based porphyrin bridging ligands, and (3) porph-MOFs containing other custom-designed porphyrin-based bridging ligands.

Journal ArticleDOI
TL;DR: In this paper, the authors highlight recent developments of energetic cocrystals and details intermolecular interactions, physical parameters and detonation properties, including 2,4,6,8,10,12-hexanitrohexaazaisowurtzitane (CL-20) and azole-based cocrystal.
Abstract: Energetic materials that can store and rapidly release large amounts of chemical energy on demand play a vital role in both military and civilian fields. Modern energetic materials should have high density, high heat of formation and possess molecular stability that allow them to be manufactured, stored and handled safely. Recently, cocrystallization technology offers a promising platform for energetic materials to achieve a desired balance between high detonation performance and low sensitivity. This paper highlights recent developments of energetic cocrystals and details intermolecular interactions, physical parameters and detonation properties. The major part of the discussion relates to the different types of energetic cocrystals including cocrystals composed of energetic molecules and solvents, 2,4,6,8,10,12-hexanitrohexaazaisowurtzitane (CL-20)-based cocrystals and azole-based cocrystals, et al. In addition, resonant acoustic mixing (RAM) technique, bead milling and spray flash evaporation technique are also introduced as means for large-scale production of nanosized energetic cocrystals.

Journal ArticleDOI
Junlei Zhang1, Lisha Zhang1, Xiaofeng Shen1, Pengfei Xu1, Jianshe Liu1 
TL;DR: In this paper, the photocatalytic properties of the BiOBr/WO3 p-n heterojunctions were investigated by degrading rhodamine B (RhB), methyl orange (MO), and para-chlorophenol (4-CP) under visible light irradiation (λ > 400 nm), respectively.
Abstract: A prerequisite for the development of photocatalysis techniques is to obtain photocatalysts with remarkable activity. Herein, we have reported BiOBr/WO3 p–n heterojunctions as novel and efficient visible-light-driven photocatalysts. The BiOBr/WO3 p–n heterojunctions have been prepared through an electrospinning–calcination–solvothermal method, and they all present a flower-like superstructure. The photocatalytic activities of these p–n heterojunctions are investigated by degrading rhodamine B (RhB), methyl orange (MO) and para-chlorophenol (4-CP) under visible light irradiation (λ > 400 nm), respectively. When RhB serves as the target pollutant, all BiOBr/WO3 p–n heterojunctions with different theoretical molar ratios of BiOBr and WO3 (1/0.5, 1/1, 1/2) exhibit higher photocatalytic activity than pure WO3 or BiOBr. Especially, the BiOBr/WO3 p–n heterojunction with a molar ratio of 1/1 displays the highest photocatalytic activity among all the as-synthesized catalysts, even higher than the activity from the mixture of two individual photocatalysts with the same weight of components (WO3 and BiOBr). In addition, when MO or 4-CP acts as the target pollutant, the BiOBr/WO3 p–n heterojunction with a molar ratio of 1/1 still exhibits excellent photocatalytic performance. Furthermore, the recycling experiment confirms that the BiOBr/WO3 p–n heterojunction is essentially stable during the photocatalytic process. The enhanced photocatalytic activity of the BiOBr/WO3 p–n heterojunction is predominantly attributed to the efficient separation of photogenerated electrons and holes. The photogenerated holes (h+) and superoxide radical anions (˙O2−) have been found to be the primary reactive species responsible for the nearly complete mineralization of RhB dye in water.

Journal ArticleDOI
TL;DR: The ability of modulating the properties of metal–organic frameworks (MOF) on demand by external light-stimuli is a most appealing pathway to enhance their performance in storage and separation and to render novel advanced applications.
Abstract: The ability of modulating the properties of metal–organic frameworks (MOF) on demand by external light-stimuli is a most appealing pathway to enhance their performance in storage and separation and to render novel advanced applications. Photoswitchable linkers of different nature have been inserted in several MOF structures either as integral parts of their scaffolds or as guests in the pores. In this highlight we analyse the different strategies and expose some aspects that should be considered in the design of new generations of photoswitchable MOFs.

Journal ArticleDOI
TL;DR: The anion-π interaction has attracted increasing attention ever since its inception about two decades ago as mentioned in this paper, leading to several design strategies and several relevant examples that illustrate the viability of these strategies and the importance of anion−π interactions in crystal engineering.
Abstract: For well over half a century part of the scientific community has been committed to understanding and predicting how molecules recognize each other. This subject of unceasing interest, ‘supramolecular chemistry’, relies on the understanding of noncovalent interactions. Among the noncovalent forces, the anion–π interaction has attracted increasing attention ever since its inception about two decades ago. This highlight article first summarizes some of the fundamental aspects of this interaction leading to several design strategies. In the main body we highlight some relevant examples that illustrate the viability of these strategies and the importance of anion–π interactions in crystal engineering.

Journal ArticleDOI
TL;DR: In this article, two inorganic-organic hybrid solid electrolyte systems for lithium ion batteries are described. But the safety issues of current Li ion batteries based on organic liquid electrolytes, which are volatile and flammable, are highlighted.
Abstract: Lithium ion batteries (LIBs) have achieved great success in powering portable electronic devices in our modern society, and are to find use in the electrification of transportation and the storage of wind or solar energy in smart grids in the near future. However, there is increasing concern on the safety issues of current LIBs based on organic liquid electrolytes, which are volatile and flammable. This leads to the exploration and development of solid electrolytes to improve the safety of next-generation high-energy LIBs. In this review, we describe two inorganic–organic hybrid solid electrolyte systems for LIBs. Firstly, we present polymer electrolytes with different types of inorganic fillers, discussing how the fillers affect the electrochemical and physical properties of the electrolyte. Secondly, we introduce recent progress in MOF-based solid electrolytes and show how MOFs can contribute to such an inorganic–organic hybrid system. Finally, outlook and future directions for safe and high performance inorganic–organic hybrid solid electrolytes are proposed.

Journal ArticleDOI
TL;DR: In this article, a combination of theoretical and experimental techniques were employed to study the metal-organic framework (MOF)-mechanics central to the paddle-wheel Cu3(BTC)2 porous structure, commonly designated as HKUST-1.
Abstract: We employed a combination of theoretical and experimental techniques to study the metal–organic framework (MOF)-mechanics central to the paddle-wheel Cu3(BTC)2 porous structure, commonly designated as HKUST-1. Lattice dynamics of the hybrid framework at below 18 THz were measured by means of Raman and synchrotron far-infrared spectroscopy, and systematically correlated to collective vibrational modes computed from ab initio density functional theory (DFT). We have identified a number of intriguing low-energy framework vibration mechanisms, reminiscent of the ‘trampoline-like’ deformations and new oscillatory motions associated with Cu paddle-wheel ‘molecular rotors’. The three independent single-crystal elastic constants of the HKUST-1 (i.e. C11, C12 and C44) were calculated using the DFT approach, taking into account the effects of dispersion corrections. We established the full elasticity solutions accompanying detailed deformation mechanisms that control its anisotropic mechanical properties, ranging from the Young's and shear moduli to linear compressibility and Poisson's ratio. Our results support the notion that the co-existance of soft modes and intrinsic shear distortions connected to the THz lattice dynamics dictate a range of anomalous elastic phenomena, for example: negative Poisson's ratio (auxeticity), negative thermal expansion (NTE), and exceedingly low shear moduli properties.

Journal ArticleDOI
TL;DR: It is shown that the method can be used to generate hypothetical MOFs where the most common realization of a net, called the barycentric representation, will not produce a viable structure, and when combined with a robust force field based geometry optimizer, the method is able to generate large and structurally diverse hypothetical databases for virtual screening purposes.
Abstract: Here we present a method for constructing hypothetical crystalline nanoporous materials, such as metal–organic frameworks (MOFs), using a graph theoretical approach. The method takes as input the discrete secondary (or structural) building units (SBUs) with defined connection points, and a desired 3-dimensional net topology in the form of a labelled quotient graph. The hypothetical materials are constructed based on the principle that using a labelled quotient graph obtained, for example from the reticular chemistry structure resource (RCSR), one can construct a net embedding in 3-D Euclidean space with an infinite number of different representations. Thus, crystalline structures can be realized by manipulating a net's embedding such that vertices of the net match the geometries of the desired SBUs. To demonstrate the methodology, 46 different network topologies (i.e.tbo, pcu), are used to build MOFs from the same pair of 4-coordinate and 3-coordinate SBUs. We further show that the method can be used to generate hypothetical MOFs where the most common realization of a net, called the barycentric representation, will not produce a viable structure. When combined with a robust force field based geometry optimizer, the method can be used to generate large and structurally diverse hypothetical databases for virtual screening purposes.

Journal ArticleDOI
TL;DR: In this article, the size of metal-organic framework (MOF) nanoparticles (Zr-fum MOF NPs) was determined using various common characterization methods, such as powder X-ray diffraction (PXRD), atomic force microscopy (AFM), scanning electron microscopy and TEM.
Abstract: While the size of nanoparticles (NPs) seems to be a concept established in the field of NPs and is commonly used to characterize them, its definition is not that trivial as different “sizes” have to be distinguished depending on the physical characterization technique performed to measure them. Metal–organic frameworks (MOFs) are known for their crystallinity, their large variety of compositions due to a huge number of inorganic building blocks that can be combined with almost endless organic linkers, their tunable pore structure, their ultrahigh porosity, and the different ways their backbones can be functionalised. The combination of these features with the nanoworld offers manifold perspectives for the synthesis of well-defined MOF nanoparticles (NPs), whose size attribute should be accurately determined as it strongly influences their physicochemical properties (at this length scale). In order to elucidate size determination, we synthesised zirconium fumarate metal–organic framework nanoparticles (Zr-fum MOF NPs) and characterized them using various common characterization methods. Herein, we compare the results of different solid-state methods, including powder X-ray diffraction (PXRD), atomic force microscopy (AFM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) to data obtained from dispersion-based methods, such as fluorescence correlation spectroscopy (FCS) and dynamic light scattering (DLS). In doing so, we illustrate the challenge of finding the appropriate method for obtaining a MOF NP size that is meaningful in the context of the desired application. Moreover, we demonstrate the importance of applying multiple complementary techniques as soon as the MOF NP size is considered. Throughout this paper, we highlight and define some reasonable recommendations of how the MOF NP size should be explored.

Journal ArticleDOI
Nan Zhang1, Yi-Jun Xu1
TL;DR: In this paper, a review of recent advances in developing strategies to assemble efficient GR-semiconductor composite photocatalysts is highlighted, which can be mainly classified into three aspects: optimization of individual components, including maximization of the functions of graphene and optimization of photoactive semiconductors.
Abstract: Graphene (GR)–semiconductor composite-based photocatalytic systems have received ever-increasing attention due to the attractive possibilities they provide to alleviate environmental and energy issues. Extensive endeavours have been made to construct high-performance GR–semiconductor composite photocatalysts for solar energy conversion. In this review, recent advances in developing strategies to assemble efficient GR–semiconductor composite photocatalysts are highlighted. These advances can be mainly classified into three aspects. The first is the optimization of individual components, including maximization of the functions of graphene and optimization of the photoactive semiconductors. The second is interface engineering between graphene and semiconductors. The third is the design and optimization of GR–semiconductor composite photocatalysts from a system-level consideration. Finally, it is proposed that combining these advances together with theoretical investigations will take us further along the road to advancing GR–semiconductor composite-based photocatalysis. Truly smart GR–semiconductor composite photocatalysts with robust structural and functional infrastructure are anticipated to be forthcoming.

Journal ArticleDOI
TL;DR: In this article, a new and an existing Ce-based metal-organic framework (MOF) having a UiO-66 framework topology and incorporating azide and nitro functional groups in their frameworks have been successfully used as turn-on fluorescent probes for the sensing of H2S under physiological conditions.
Abstract: A new and an existing Ce-based metal–organic framework (MOF) having a UiO-66 framework topology and incorporating azide and nitro functional groups in their frameworks have been successfully used as turn-on fluorescent probes for the sensing of H2S under physiological conditions. The azide (1-N3) and nitro (2-NO2) functionalized Ce MOFs have been synthesized under similar solvothermal conditions (100 °C, 15 min) using ammonium cerium(IV) nitrate and H2BDC-X (BDC = 1,4-benzenedicarboxylate; X = –N3 for 1-N3 and –NO2 for 2-NO2) linkers in DMF/H2O (DMF = N,N-dimethylformamide) mixtures. The phase purity of both compounds has been confirmed by X-ray powder diffraction (XRPD) analyses, infrared spectroscopy and thermogravimetric (TG) analyses. The thermally activated forms of both compounds (1′-N3 and 2′-NO2) show fast response time, excellent selectivity and sensitivity for the detection of H2S under physiological conditions (HEPES buffer, pH 7.4) through the fluorescence ‘turn-on’ mechanism. The detection limits (12.2 μM for 1′-N3 and 34.8 μM for 2′-NO2) of both materials lie within the range of the H2S concentration observed in biological systems. The materials can selectively detect H2S even in the presence of other competing biomolecules. Apart from the sensing of H2S, both compounds exhibit high uptake of CO2 (2.6 mmol g−1 for 1′-N3 and 3.7 mmol g−1 for 2′-NO2) at 0 °C and 1 bar. Thus, the materials are promising candidates in the fields of H2S sensing and CO2 capture.

Journal ArticleDOI
TL;DR: In this paper, the authors summarized the structure and growth of hybrid perovskite single crystals and highlighted the enormous challenges and promising outlook of these active topics, and summarized the huge challenges and the promising outlook.
Abstract: Hybrid halide perovskite based solar cells have demonstrated unprecedented progress in their efficiency, leading to efficiencies of up to 22.1%, in the past six years. Moreover, their intriguing properties of high dielectric constant, wide optical absorption range, low trap density, low non-radiative recombination and photoluminescence have attracted great research interest in the fields of optoelectronic applications and photovoltaics. This review briefly outlines the frontier of the research fields of perovskite materials, and summarizes the structure and growth of hybrid perovskite single crystals. Finally, the enormous challenges and the promising outlook of these active topics are highlighted.

Journal ArticleDOI
TL;DR: In this article, the authors summarize the recent advances in metal-organic frameworks (MOFs), including homo-and hetero-IMOFs, and summarize their topologies.
Abstract: Interpenetration usually refers to two or more individual polymeric networks with the same or different components catenated with each other, which is a frequently observed phenomenon in metal–organic frameworks (MOFs). The interpenetrating metal–organic frameworks (IMOFs) show fascinating architectures and topologies, as well as exhibit improved functions and applications. In this highlight, we summarize the recent advances in IMOFs, including homo- and hetero-IMOFs.

Journal ArticleDOI
TL;DR: In this paper, in situ results obtained for ten different material systems, and show that nucleation of nanoparticles in solvothermal reactions expose a fascinating chemical richness spanning from mono-metal to complex polymer precursor species, which, through a specific system-dependent multistep reaction mechanism, develop into pristine nanocrystals.
Abstract: Nucleation phenomena are of critical importance in numerous areas of science and everyday life. For decades the prevailing models to explain nucleation have been based on thermodynamic arguments without consideration of the chemical nature of the specific system. Even though newer models have included system-dependent variables, the quantitative atomistic differences are largely ignored. As a consequence, nucleation processes are treated on a “particle” or “monomer” level without discussion of the true atomic scale “chemistry of nucleation”. In the past couple of years, in situ studies of solvothermal reactions have considerably changed the experimental insight into nucleation phenomena, and especially the measurement of X-ray total scattering data and the subsequent pair distribution function analysis have proven to be vital tools. Here we discuss in situ results obtained for ten different material systems, and show that nucleation of nanoparticles in solvothermal reactions expose a fascinating chemical richness spanning from mono-metal to complex polymer precursor species, which, through a specific system-dependent multistep reaction mechanism, develop into pristine nanocrystals. It is argued that it is time to introduce a paradigm shift in the general nucleation theory and move away from the “one model fits all” to a chemistry-based approach rooted in atomic scale insight.

Journal ArticleDOI
TL;DR: In this paper, a series of five lanthanide(III) metal-organic frameworks with a general formula of [Ln3(bcpb)4(μ-HCOO)(μ-H2O)2(DEF)]n (1−5) was generated by solvothermal reactions from Ln(NO3)3·6H 2O {Ln = Eu (1), Tb (2), Gd (3), Dy (4), and Sm (5)} and 3,5-bis(3-carboxyp
Abstract: A new series of five lanthanide(III) metal–organic frameworks with a general formula of [Ln3(bcpb)4(μ-HCOO)(μ-H2O)(H2O)2(DEF)]n (1–5) was generated by solvothermal reactions from Ln(NO3)3·6H2O {Ln = Eu (1), Tb (2), Gd (3), Dy (4), and Sm (5)} and 3,5-bis(3-carboxyphenyl)pyridine (H2bcpb) in an aqueous N,N-diethylformamide (DEF) medium. The obtained products were characterized by elemental analysis, FT-IR spectroscopy, thermogravimetric analysis (TGA), and powder and single crystal X-ray diffraction. The latter reveals that all compounds (1–5) are isostructural and feature very intricate 2D metal–organic frameworks. These were topologically analyzed, revealing a very complex hexanodal underlying net that can be simplified further to a binodal 3,5-connected layer with the 3,5L52 topology. Solid-state photoluminescence properties of 1–5 were studied in detail. Compound 1 exhibits a strong red luminescence upon excitation at 338 nm and its lifetime is 532 μs. Compound 2 shows an intense green luminescence upon excitation at 336 and its lifetime is 981 μs. The triplet state (3ππ*) of bcpb2− studied by using the Gd(III) derivative 3 demonstrated that the ligand effectively populates Tb(III) emission (Φ = 70.96%), whereas the corresponding Eu(III) derivative 1 shows a weak luminescence efficiency (Φ = 15.81%) as the triplet state of bcpb2− has a poor match with the 5D0 energy level of Eu(III). A notable feature of 1 is its remarkable sensing ability for Cu2+ ions and 2,4,6-trinitrophenol (TNP). Besides, a series of heterobimetallic Tb-based MOFs, [Tb3(1−x)Eu3x(bcpb)4(μ-HCOO)(μ-H2O)(H2O)2(DEF)]n {x = 0.001, 0.002, 0.003, 0.01, 0.02, 0.03, 0.04, 0.10, 0.15, 0.20} (compounds 2a–2j, respectively), was prepared. The luminescence studies reveal that the simultaneous presence of the characteristic sharp emission bands of Eu3+ and Tb3+ allows the tuning of the photoluminescence colors of such materials by adjusting the doping concentration of the Eu3+ ions.

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Mi Kyung Kim1, Taewoo Jeon1, Hyung Il Park1, Ju Min Lee1, Soo Ah Nam1, Sang Ouk Kim1 
TL;DR: In this article, a CH3NH3PbII3 perovskite film with a lead(II) thiocyanate additive was used to enlarge the crystal size from the nanometer to the micrometer scale.
Abstract: We demonstrate effective morphology control of a CH3NH3PbI3 perovskite film with a lead(II) thiocyanate additive. The perovskite crystal size is remarkably enlarged from the nanometer to the micrometer scale with only 3% Pb(SCN)2 in solid perovskite films. Large-sized perovskite crystals enable effective enhancement of the carrier lifetime, which eventually leads to the overall improvement of the device performance of perovskite solar cells.

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TL;DR: In this paper, the shape-dependent electrocatalytic activity of nickel phosphide nanoparticles (Ni2P NPs) for hydrogen evolution reaction (HER) was investigated, showing that the Ni2P(001) surface would have preferential interactions with the adsorbent and a lower activation barrier for hydrogen adsorption, promoting the overall rate of HER.
Abstract: The preparation of size- and shape-controlled nanoparticles has enabled the understanding of important nanoscale catalytic phenomena, resulting in the design of advanced catalysts with enhanced activities and selectivities. Metal phosphides have recently emerged as a promising class of non-precious metal catalysts for hydrogen evolution reaction (HER), which is a cornerstone in clean and environmentally benign hydrogen production. Although significant progress has been made in metal phosphide catalysts, the impact of the metal phosphide shape has not yet been explored. Herein, we investigated the shape-dependent electrocatalytic activity of nickel phosphide nanoparticles (Ni2P NPs) for the HER. Spherical Ni2P NPs mainly composed of the Ni2P(001) surface showed higher HER activity than rod-shaped Ni2P NPs with the Ni2P(210) surface in terms of overpotential, Tafel slope, and turnover frequency. The results imply that the Ni2P(001) surface would have preferential interactions with the adsorbent and a lower activation barrier for hydrogen adsorption, promoting the overall rate of HER. This study highlights the importance of morphology control in electrocatalysts to boost catalytic performances.

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TL;DR: In this paper, the authors highlight the recent advances in the rational design of MOFs based on imidazole derivatives from their and other research groups; they also provide new insights into the rational designing of organic tectons and the construction of these advanced crystalline materials with desirable properties and functionalities.
Abstract: Imidazole is a fundamental building unit possessing a conjugated five-membered ring system with two N-donor coordination sites. The parent imidazole nucleus can be derivatized to three types of compounds at the 1-, 2-, or 4-positions, generating 1, 2, or 4-imidazole-containing ligands, or can be endowed with other functional groups to form multi-functional ligands. Imidazole and its derivatives have been widely employed as excellent candidates for targeted metal–organic frameworks (MOFs) in the domain of coordination chemistry. Moreover, recent reports show a boom in exploratory synthesis using imidazole derivatives to construct novel MOFs due to their distinct characteristics. In consideration of the rapidly growing research on imidazole ligands, herein, we would like to highlight the recent advances in the rational design of MOFs based on imidazole derivatives from our and other research groups; we would also like to provide new insights into the rational design of organic tectons and the construction of these advanced crystalline materials with desirable properties and functionalities.

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TL;DR: The perovskite solar cell is based on organic-inorganic lead halides such as methylammonium CH3NH3PbI3 or formamidinium HC(NH2)2PcI3 as light harvesters as discussed by the authors.
Abstract: The perovskite solar cell is based on organic–inorganic lead halides such as methylammonium CH3NH3PbI3 or formamidinium HC(NH2)2PbI3 as light harvesters. Since the first report on a long-term, durable, 9.7% efficient solid-state perovskite solar cell in 2012, the perovskite solar cell has received great attention because of facile processing and superb photovoltaic performance. As a result, a power conversion efficiency exceeding 22% was certified in 2016. To achieve a high efficiency perovskite solar cell, understanding the crystal structure and opto-electronic properties of organic–inorganic lead halide perovskites are of importance. Growth of perovskite on substrate without traps and grain boundaries is equally important for attaining high efficiency. In this article, the emergence of the perovskite solar cell, the structural and opto-electronic characteristics of perovskite materials and the methodologies of perovskite crystal growth both from solution and on a substrate are reviewed.