Search

The potential threat that has originated from chemical warfare agents (CWAs) has promoted the development of advanced materials to enhance the protection of civilian and military personnel. Zr-based metal–organic frameworks (Zr-MOFs) have recently been demonstrated as excellent catalysts for decomposing CWAs, but challenges of integrating the microcrystalline powders of Zr-MOFs into monoliths still remain. Herein, we report hierarchically porous monolithic UiO-66-X xerogels for the destruction of CWAs. We found that the UiO-66-NH2 xerogel with a larger pore size and a higher surface area than the UiO-66-NH2 powder possessed better degradability of 2-chloroethyl ethyl sulfide (2-CEES), which is a sulfur mustard simulant. These UiO-66-X xerogels exhibit outstanding performance for decomposing CWAs. The half-lives of vesicant agent sulfur mustard (HD) and nerve agent O-ethyl S-[2-(diisopropylamino)ethyl] methylphosphonothioate (VX) are as short as 14.4 min and 1.5 min, respectively. This work is, to the best of our knowledge, the first report on macroscopic monolithic UiO-66-X xerogels for ultrafast decomposition of CWAs.

High lithium ion transference number (tLi+) is one of the requirements of polymer electrolytes for utilization in lithium secondary batteries. Herein, graphene oxide (GO) is used as a filler to fabricate the homogeneous gel polymer electrolyte (GPE) for pursuing high tLi+. The effect of GO on the whole properties of gel polymer electrolytes including conductivity, lithium ion transference number, electrochemical window, electrochemical stability, and cycling performance are explored. Impressively, the GPE containing 0.3 wt% of GO (labeled as GPE-0.3%) demonstrates a high lithium ion transference number of 0.79 and improved electrochemical stability. The LFP/Li battery with GPE-0.3% as the separator shows excellent electrochemical cycle stability and Coulomb efficiency at 25 °C. The discharge specific capacity retention rate of this battery is 94.4% after 100 cycles at 0.2C. All these features make the gel polymer electrolyte useful as a separator of lithium metal batteries for high-performance lithium ion conductors, which exhibits high safety.

Detoxifying materials against chemical warfare agents (CWAs) and their simulants are highly desired for proper handling of contamination by and destruction of CWAs. Herein, we report a facile layer-by-layer fabrication of core-shell Fe3O4@UiO-66-NH2 and its application in fast degradation of CWA simulants. The Fe3O4@UiO-66-NH2 composite was prepared through a layer-by-layer epitaxial growth strategy, by alternately immersing Fe3O4 nanoparticles in ethanol solutions of a metal node [Zr6O4(OH)4]12+ precursor and organic linkers [NH2-BDC, 2-aminoterephthalic acid], respectively, and separating using a magnet. As confirmed by characterization results, the Fe3O4@UiO-66-NH2 composites with 24.4 μmol/g Zr6 node content showed a well-defined core-shell structure as well as good thermal and chemical stability. These core-shell magnetic metal-organic frameworks (MOFs) were further tested in the catalytic hydrolysis of dimethyl-4-nitrophenyl phosphate (a nerve agent simulant) and demonstrated 36 times higher catalytic activity than the UiO-66-NH2 powder due to their highly defective surface, high percentage of MOFs on the surface, and their rich mesoporous structure. Since magnetism was retained after the coating of MOFs, Fe3O4@UiO-66-NH2 could be easily recovered and reused after catalysis.

Fabrication of graphene-based conductive circuits via inkjet printing processes would be very significant, but preparation of graphene inks which can be used in ordinary household inkjet printer is still a challenge. Graphene oxide (GO) is an important graphene derivative with good dispersion properties in water, because it has a lot of oxygen-containing functional groups. In this paper, the relationship between the concentration of GO and the viscosity and surface tension of its dispersion were studied first, GO were prepared by modified Hummers' method. Moreover, the influence of two surfactants-sodium dodecyl sulfate (SDS) and Triton-X100 (TX-100) on viscosity and surface tension of inks were also investigated. It was found that the concentration of GO was 3.9 mg/mL, and the amount of the addition of SDS and TX-100 were 1 mg/mL and 2.5 mg/mL respectively, which can form stable GO-based inks. Finally, the resultant GO-based inks can be printed by home inkjet printer HP-1010 on normal printing paper, flexible polyimide film and thin aluminum foil. It is expected that the development of inkjet printable GO-based inks will decrease the cost of the preparation of graphene electrode/circuits and open up new ways for the application of GO-based thin film and patterns.

The preparation and development of novel optical thin films are of great importance to functional optical and opto-electric components requiring a low refractive index. In this study, a typical metal-organic framework (MOF), MIL-101(Cr), is selected as the research model. The corresponding MOF nanoparticles are prepared by a hydrothermal method and the optical thin films are successfully prepared by spin-coating. The optical properties of the corresponding MOF thin films are controlled by changing the type of functional groups on the benzene ring of the ligand (terephthalic acid) on MOFs. The functional groups are hydrogen atoms (H), electron donating groups (–NH2, –OH) and electron withdrawing groups (–NO2, –(NO2)2 or F4), respectively. It is found that the effective refractive index ( n eff) of MOF thin films decreases along with the increasing voids among MOF nanoparticles. In addition, the extinction coefficient ( k ) increases with the addition of electron donating groups, and decreases with the addition of electron withdrawing groups. Among the MOFs used in this study, the n eff of NO2-MIL-101(Cr) containing electron withdrawing groups is as low as ~1.2, and value of k is particularly low, which suggests its potential application in antireflective devices. In addition, the intrinsic refractive index ( n dense) of the dense MOF materials evaluated according to their porosity increases with the number of the functional groups, and the n dense of the two nitro-substituted MOFs is greater than that of the single nitro-substituted one, and the latter is bigger than that of hydroxyl-substituted one, which is close to that of amino-functionalized one. The diversity of ligands in MOFs makes them a promising new generation of optical materials.

Adding inorganic fillers to polymer electrolytes is one of the main means to improve ionic conductivity. However, the filler will aggregate, causing the problem of incompatibility between the electrolyte and the metal lithium negative electrode. In this paper, we grafted polyethylene oxide (PEO) on the surface of the filler graphene oxide (GO) (the product is referred to as GO@PEO) to promote the compatibility of GO with the electrolyte matrix (PVDF-HFP). The problem of improving the dispersibility of the filler and the compatibility of the gel electrolyte (GPE) with metallic lithium is achieved.

This paper systematically studies the influence of temperature during KOH activation of graphene on quantities and types of oxygen-containing groups, pore structure, specific surface area, and performance of supercapacitor. The changes of the amount and types of oxygen-containing functional groups were observed with the aid of Fourier transform infrared spectroscopy, Raman and X-ray photoelectron spectroscopy. The pore structure and specific surface area were characterized by means of X-ray powder diffraction, N2 adsorption-desorption and transmission electron microscopy. Electrochemical properties were assessed by cyclic voltammetry, electrochemical impedance and galvanostatic charge-discharge. As the temperature increased, the oxygen content of activated graphene decreased, while its specific surface area increased. The specific capacitance of the activated graphene first increased and then decreased with a maximum (326 F/g) at 400 °C. When the temperature was 800 °C, the surface area of the material peaked (3269 m2/g), and the specific capacitance was 204 F/g.

A mechanical ball milling method for ultrafast synthesis of a nickel-based metal organic framework (Ni-MOF) has been proposed. The Ni-MOF was successfully synthesized in merely one minute without any solvent, additives, or preliminary preparation. The effect of milling time, mechano-frequency, type of assistant liquid, and amount of assistant water were systematically explored. It was found that the product can be obtained even only at a mechano-frequency of 10 Hz within one minute without any external solvent-assist, which indicated that the crystal water present in the nickel precursor was sufficient to promote MOF formation. Increasing the milling time, raising the mechano-frequency, and the addition of assistant solvent could promote the reaction and increase the yield. The method is rapid, highly efficient, eco-friendly, and has great scalability. The product generated within merely one minute even exhibited high capacitance.

Metal-organic frameworks (MOFs) have been used in adsorption, separation, catalysis, sensing, photo/electro/magnetics, and biomedical fields because of their unique periodic pore structure and excellent properties and have become a hot research topic in recent years. Ball milling is a method of small pollution, short time-consumption, and large-scale synthesis of MOFs. In recent years, many important advances have been made. In this paper, the influencing factors of MOFs synthesized by grinding were reviewed systematically from four aspects: auxiliary additives, metal sources, organic linkers, and reaction specific conditions (such as frequency, reaction time, and mass ratio of ball and raw materials). The prospect for the future development of the synthesis of MOFs by grinding was proposed.

A flexible metal–organic framework (MOF)-based one-dimensional photonic crystal (1DPC) was fabricated by a spin-coating method. The flexible MOF, NH2-MIL-88B (MIL = Materials from Institute Lavoisier), was selected and implanted as the intrinsic functional layer of 1DPCs because of its selective breathing behavior upon exposure to various guests. TiO2 nanoparticles were used as another component to ensure a high refractive index contrast. The optical properties of the 1DPCs were tailored by varying the number of bilayers, incident angles, and physical thickness of the individual slabs. The fabricated 1DPCs showed a selective response toward various organic vapors as a result of the selective breathing behavior of the NH2-MIL-88B layer. Selective quantitative measurements of the ethanol concentration were achieved when the 1DPC was exposed to the vapors of an ethanol and water mixture. The fabricated 1DPCs exhibited high long-term, thermal, and mechanical stability, which are beneficial for practical applications.

Chemically functionalized graphene (CFG) is proposed as a novel nanoscale optical heater by uniformly dispersing it in poly(dimethylsiloxane) (PDMS) matrix. And subsequently, a simple, fast, and localized heating method on microfluidic chips is demonstrated. CFG is prepared through simultaneous modification and reduction of graphene oxide with dodecylamine by a solvothermal route. It is well dispersed in PDMS suspension to form uniform CFG/PDMS composite due to the presence of the long-dodecyl chain. The obtained CFG/PDMS composites are readily made into microfluidic chips by standard soft lithography. The localized optical heating on the chip is realized by employing a conventional semiconductor laser as light source. The prepared chips with low to 0.05 wt% CFG contents can exhibit temperature increase (

In this article, the fabrication of an active organic–inorganic one-dimensional photonic crystal structure to offer electrothermal fluorescence switching is described. The film is obtained by spin-coating of liquid crystal elastomers (LCEs) and TiO2 nanoparticles alternatively. By utilizing the property of LCEs that can change their size and shape reversibly under external thermal stimulations, the λmax of the photonic band gap of these films is tuned by voltage through electrothermal conversion. The shifted photonic band gap further changes the matching degree between the photonic band gap of the film and the emission spectrum of organic dye mounting on the film. With rhodamine B as an example, the enhancement factor of its fluorescence emission is controlled by varying the matching degree. Thus, the fluorescence intensity is actively switched by voltage applied on the system, in a fast, adjustable, and reversible manner. The control chain of using the electrothermal stimulus to adjust fluorescence inten...

A new graphene-based electrochemical biosensor was constructed and applied for the simple, rapid and highly selective determination of glucose. The modified glassy carbon electrode (GCE) was prepared using dopamine (DA) as a reducing agent for graphene oxide (GO) and as a capping agent to stabilize and coat the resulting reduced graphene oxide (RGO) surface as it can polymerize to form polydopamine (PDA). PDA-RGO composites were dropped onto a glassy carbon electrode surface, and glucose oxidase (GOx) was immobilized on the surface of the composites by Michael addition. Finally, Pt nanoparticles (PtNPs) were electrodeposited on the modified electrode. Such modified electrodes (denoted as GCE/PDA-RGO/GOx/PtNPs) were characterized by UV-visible spectroscopy, atomic force microscopy, X-ray power diffractometry, Fourier-transform infrared spectroscopy, and scanning electron microscopy. Electrochemical behaviors were investigated by cyclic voltammetry and electrochemical impedance spectroscopy. The fabricated biosensor exhibited a high sensitivity of 33 μA mM−1 cm−2 over a wide linear range of 0.2 mM to 1 mM, good stability, excellent repeatability, and a detection limit of 0.10 mM.

A biosensor based on a combination of cytochrome c (Cyt c), electrochemical reduced graphene oxides (ERGO), and gold nanoparticles (AuNPs) on a glassy carbon electrode (GCE) was fabricated. The proposed biosensor electrode was denoted as GCE/ERGO-Nafion/AuNPs/Cyt c/Nafion, where ERGO-Nafion was deposited by dropping graphene oxides-Nafion mixed droplet first and following electrochemical reduction, AuNPs were directly deposited on the surface of the ERGO-Nafion modified electrode by electrochemical reduction, and other components were deposited by the dropping-dry method. The effect of the deposition amount of AuNPs on direct electrochemistry of Cyt c in the proposed electrode was investigated. The hydrogen peroxide was taken to evaluate the performance of the proposed biosensor. The results showed that the biosensor has great analytical performance, including a high sensitivity, a wide linear range, a low detection limit, and good stability, reproducibility, and reliability.

2.5-Dimension hollow silica fiber reinforced nitride (2.5D HSFRN) composites were fabricated by repeated infiltration and pyrolysis from hybrid polyborosilazane precursor. The effects of precursor infiltration and pyrolysis (PIP) cycles on densification behavior, mechanical properties, dielectric properties, and microstructures of the composites were investigated. With increasing PIP cycles, the density of 2.5D HSFRN composites increases, the mechanical properties increase accordingly, however, the dielectric properties decrease. The composites prepared after three PIP cycles, which have moderate flexural strength of 77.4MPa and elastic modulus of 20.7GPa, low dielectric constant of 2.98 and loss angle tangent of 3.9×10-3, exhibit suitable mechanical and dielectric properties. The calculation results of dielectric performance show that 2.5D HSFRN composites have good broadband wave-transparent properties, which result from high purity hollow silica fibers with excellent dielectric properties and low density nitride matrix.

In this article, graphite oxide was prepared via Hummers method, then reduced by L-ascorbic acid to obtain colloidal suspension of graphene. The resultant graphene was characterized by FT-IR, UV-vis, Raman, XRD, AFM, TEM in detail, and it was found that the the sp2 domain of graphene oxide is restored efficiently, the suspension is very stable and most of the graphene is single-layer. Compared to hydrazine hydrate, L-ascorbic acid has higher deoxygenation efficiency and inclines to gain few-layer graphene and its stable suspensions.

To prepare nanoscale coordination polymers (NCPs) which can exhibit intense luminescence have attract an increasing interest. In this paper, we present the synthesis of a novel example of discus-like luminescent nanoscale Eu (III)-carboxylate coordination polymers. The organic ligand is a derivative of terephthalate (Na2L) with a big side group. The Eu (III)-L NCPs was synthesized through microemulsion method, and the morphology can alter along with the changing of metal: ligand ratios. XRD results reveal that the self-assembled disk-like NCPs exhibit long-range ordered structures. The luminescent measurements showed that the resultant NCPs not only exhibits typical fluorescence of Eu (III), but also can maintain the inherent fluorescence of the ligands.

n this paper, a non-enzymatic hydrogen peroxide (H2O2) sensor, based on Au nanoparticles (AuNPs) electrodepos‐ ited on an electrochemically reduced graphene oxide(ER‐ GO)-Nafion modified glass carbon electrode (GCE), was reported. The graphene oxide-(GO-)Nafion nanocompo‐ sites were first assembled on the GCE surface to produce a GO-Nafion electrode. GO was then electrochemically reduced to produce an ERGO-Nafion modified GCE (to be subsequently denoted as GCE/ERGO-Nafion). Afterwards, AuNPs were electrodeposited on the modified GCE to form a GCE/ERGO-Nafion/AuNPs electrode. The ERGO-Nafion nanocomposites and the electrodeposited AuNPs were characterized by infrared spectroscopy and scanning electron microscopy (SEM). The results showed that the GO was reduced successfully and the AuNPs were uniformly dispersed on the GCE/ERGO-Nafion electrode with a size of about 48nm. The cyclic voltammograms and the am‐ perometric method were used to evaluate the electrocata‐ lytic properties of the GCE/ERGO-Nafion/AuNPs electrode. The results showed that the modified electrode displayed good electrocatalytic activity in relation to the reduction of H2O2 with a detection limit of 2 μM of (H2O2) based on a signal-to-noise ratio of three. The sensor also indicated great sensitivity (574.8 μA/(mM cm2)), wide linear range (0.02-23 mM), good selectivity and reproduci‐ bility, and long-term stability.

Keywords: Metal-organic frameworks; Graphene; Dye; Wastewater; Porous materials Abstract. Metal-organic frameworks (MIL-100)/graphene oxide composites (MOFs/GO) with different graphene oxide (GO) contents were prepared under hydrothermal conditions. The resultant products were then characterized by powder X-ray diffraction, infrared spectra, thermogravimetric analysis and nitrogen adsorption desorption. Methyl orange and methyl red solutions were used as simulative dye wastewater to evaluate the adsorption performance of resulted MOFs/GO composites. The results show that adsorption rate and saturated adsorption amount of dye are affected by the contents of GO in the composites and will be improved simultaneously by adding appropriate amount of GO.

Scattering spheres-embedding three-dimensional ordered macroporous (3DOM) titania(TiO2) was fabricated, by the route of colloidal spheres self-assembly, infiltration and template removal. The procedures of 3DOM structure preparation were characterized by transmission electron microscope (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD). The silica@PMMA core-shell spheres were prepared and self-assembled into colloidal crystal template. Solid material was deposited in the colloidal crystal template by spin-coating of titania nanoparticle dispersions. Subsequently, the samples were heated to 400 °C to form anatase TiO2and to remove the polymer of template, which resulted in macroporous structure with a silica sphere in each lattice pore. The conventional TiO2film, 3DOM TiO2photoanodes were also fabricated. It was found that SiO2-embedding 3DOM photoanode has the higher photocurrent efficiency than both of TiO2 film and 3DOM, because there are scattering spheres in its lattice pores which enhance the light scattering and improve the light harvest of the dye.

In this paper, the graphene oxide reducing by photochemical-thermal reduction and high-temperature thermal reduction was studied to get qualified graphene and avoid the re-aggregation. The results show that graphene obtained by both of the two reduction methods all maintained the original well-layered morphology of the graphene oxide. The graphene had smooth surface and high quality as completely reduced by high-temperature thermal method. However, the reduction the photochemical-thermal reaction was not sufficient and caused many vesicles on the graphene surface due to the low temperature and the lack of reaction time.

Graphite oxide is of great importance in preparing graphene, the average layer of graphene depends on that of graphene oxide in some extent. In this paper, we prepared graphite oxide via H3PO4/H2SO4mixed acid, then which were dried by vacuum drying in a freezer dryer and drying oven respectively, the graphite oxide powder and thin film were obtained correspondingly. After dispersing the above two forms of graphite oxide in water by shaking, stirring or supersonic wave, they were reduced in the same condition. According to the XRD, AFM results, vacuum freeze-drying was inclined to gain few-lay graphene.

We prepared graphite oxide (GO) from natural graphite by the modified Hummers method. Then graphene was prepared by ultrasonically dispersing GO in the presence of hydrazine hydrate. The samples were characterized by FTIR, Raman, Scanning electron microscope (SEM) and Transmission electron microscope (TEM). The results suggest that the graphite is oxidized to covalent bond-type graphite intercalation compounds with various oxygen functional groups (C=O, C-OH, -COOH and C-O-C). Results show that the functional groups on graphite oxide surface are mostly removed by hydrazine hydrate and graphene presents translucent slide with curly edge.

To develop a Φ510 mm SiC ultra-lightweight mirror,this paper proposes an ultra-lightweight structure with a section in ship form,an internal structure in regular-triangle,and a face plate reinforced with regular-hexagon.When the design weight is 1.85 kg,the structure performance is compared with those of other two lightweight structures with the same weight by adjusting all structure parameters.It is shown that in the same 6 point supportings on mirror backs,this ultra-lightweight structure owns absolute advantages in the gravitational deformation of mirror surface(RMS) as comparing with other two structures when the optical axis is pointed to the zenith.Furthermore,Patran\Nastran finite element software is used to simulate and calculate the gravitational deformation of the mirror surface when the axis is pointed to the horizon,and its thermodynamic and dynamical characteristics are analyzed.The results present that all performance indexes of this ultra-lightweight mirror meet requirements of applications.Finally,according to the design,a mirror blank with a weight about 2.2 kg and surface density about 10.8 kg/m2 is fabricated.With excellent performance, it has been up to the today's advanced level in the SiC ultra-lightweight mirror field.

Nanoscale lanthanide-containing metal-organic frameworks (MOFs) have more and more interest due to their great properties and potential applications, but how to construct them easily is still challenging. Here, we present a facile and rapid synthesis of Eu(III)-containing Nanoscale MOF (denoted as NMOF) under ultrasonic irradiation. The effect of the ratio and the addition order of metal ions and linkers on the morphology and size of MOFs was investigated. It is found that both of the ratio and the addition order can affect the morphology and size of 1.4-benzenedicarboxylic acid(H2BDC) -based MOFs, but they show no evident influence on that of H2aBDC-based MOFs. The former exhibit typical emission bands of Eu(III) ions, while the latter only show the photoluminescent properties of ligands.DOI: http://dx.doi.org/10.5755/j01.ms.21.4.9695

Tuning MOFs: When a metal-organic framework (MOF) with an ordered three-dimensional macroporous structure is integrated into a film, the resulting materials have an additional optical element, which can be used as a general and effective signal transducer. This, in combination with the hierarchical pore structure, makes these films interesting dynamic photonic materials with potential applications in sensors.

In this paper, we present a new strategy for efficiently enhancing fluorescence, based on the coupling of surface plasmons of metal particles with optical properties of colloidal photonic crystals. It is found that such coupling can effectively improve the near-field effect and induced plasmon effect of metal particles but also be favorable for the extraction of the emission, collectively leading to a further significant enhancement of metal-enhanced fluorescence. Finite-difference time-domain (FDTD) simulation proved the related enhancement mechanism for the designed hybrid system. As a proof of concept, an enhancement factor up to 260-fold has been experimentally achieved by using rhodamine B as test molecule, which greatly transcends those of two individual plasmonic and photonic components and is also much larger than the simple plus effects of the two components.

On the basis of the combination of colloidal and mesophase templating, as well as molecular imprinting, a general and effective approach for the preparation of hierarchically structured trimodal porous silica films was developed. With this new methodology, controlled formation of well-defined pore structures not only on macro- and mesoscale but also on microscale can be achieved, affording a new class of hierarchical porous materials with molecular recognition capability. As a demonstration, TNT was chosen as template molecule and hierarchically imprinted porous films were successfully fabricated, which show excellent sensing properties in terms of sensitivity, selectivity, stability, and regeneracy. The pore system reported here combines the multiple benefits arising from all length scales of pore size and simultaneously possesses a series of distinct properties such as high pore volume, large surface area, molecular selectivity, and rapid mass transport. Therefore, our described strategy and the resulting pore systems should hold great promise for various applications not only in chemical sensors, but also in catalysis, separation, adsorption, or electrode materials.

Herein, a facile dopamine assisted one-pot synthesis approach is proposed for the preparation of porous carbon with a specific surface area (SSA) up to 2593 m2/g through the direct pyrolysis of a mixture of glucose, NH4Cl, and dopamine hydrochloride (DAH). The glucose is adopted as the carbon source and foaming agent, NH4Cl is used as the blowing agent, and DAH is served as collaborative carbon precursor as well as the nitrogen source for the first time. The effect of dopamine on the component, structure, and SSA of the as-prepared porous carbon materials are systematically studied. The moderate addition of dopamine, which influences the condensation and polymerization of glucose, matches better with ammonium salt decomposition. The SSA of porous carbon increases first and then decreases with the increasing amount of dopamine. In our case, the porous carbon produced with 5 wt% dopamine (PC-5) achieves the maximum SSA of up to 2593 m2/g. Accordingly, it also shows the greatest electrochemical performance. The PC-5 shows a capacitance of 96.7 F/g calculated from the discharge curve at 1 A/g. It also has a good capacitive rate capacity, the specific capacitance can still maintain 80%, even at a high current density of 10 A/g. Moreover, PC-5 exhibits a good cycling stability of 98.1% capacitive retention after 1000 cycles. The proposed method may show promising prospects for preparing porous carbon materials as advanced energy storage materials, storage, and catalyst supports.

Herein we describe the employment of double-inverse opal (DIO) as a novel optical element and present a theoretical analysis of the efficiency enhancement of the designed DSSCs. We find that, compared to inverse opal (IO) as the optical element, the presence of small spheres in IO (i.e., DIO structure) produces a great light-scattering effect and broader reflection region, leading to considerable enhancement of the photocurrent efficiency of cells. Dye-sensitized solar cells (DSSCs) with one DIO layer as a mirror has a photocurrent efficiency enhancement up to 47%, which is a large improvement compared to that of the IO-coupled one (28%). More remarkably, double DIO layers as a scattering layer lead to efficient enhancement of the absorptances of DSSCs in the whole visible spectrum range (400−800 nm) and a distinct increment of about 80% of photocurrent efficiency with respect to standard ones. In this work, the optimum structural parameters of such DIO optical elements needed to achieve an efficient phot...

A surfactant containing a terminal carbon source moiety was synthesized and used simultaneously as both template molecule and carbon source. On the basis of this special structure-directing agent, an efficient strategy for producing uniform carbon nanowires with diameter below 1 nm was developed using a confined self-assembly approach. Besides the capability of producing ultralong and thin carbon wires inaccessible by the previously reported approaches, the method described here presents many advantages such as the direct use of residue iron complex as catalyst for carbonization and no requirement of conventional tedious infiltration process of carbon source into small channels. Different methods including SEM, TEM, XRD, Raman spectroscopy, and conductivity measurement were employed to characterize the formed ultrathin carbon nanofibers. Additionally, the described strategy is extendable. By designing an appropriate surfactant, it is also possible for the fabrication of the finely structured carbon network and ultrathin graphitic sheets through the construction of the corresponding cubic and lamellar mesostructured templates.

Optical properties, which determine the application of optical devices in different fields, are the most significant properties of optical thin films. In recent years, Metal-organic framework (MOF)-based optical thin films have attracted increasing attention because of their novel optical properties and important potential applications in optical and photoelectric devices, especially optical thin films with tunable optical properties. This study reports the first example of tuning the optical properties of a MOF-based optical thin film via post-modification. The MOF-based optical thin film was composed of NH2-MIL-53(Al) nanorods (NRs) (MIL: Materials from Institute Lavoisier), and was constructed via a spin-coating method. Three aldehydes with different lengths of carbon chains were chosen to modify the MOF optical thin film to tune their optical properties. After post-modification, the structural color of the NH2-MIL-53(Al) thin film showed an obvious change from purple to bluish violet and cyan. The reflection spectrum and the reflectivity also altered in different degrees. The effective refractive index (neff) of MOFs thin film can also be tuned from 1.292 to 1.424 at a wavelength of 750 nm. The success of tuning of the optical properties of MOFs thin films through post-modification will make MOFs optical thin films meet different needs of optical properties in various optical and optoelectronic devices.

Both reduction and cross-linking can improve the mechanical performance of graphene/polymer composites. However, few reports exist on the comparison and combination of both methods. Taking graphene oxide/polyvinyl alcohol composite film as its model, this study focuses on the effect of reduction and cross-linking (as well as their order) on the composite film's tensile strength. GO/PVA composite films were prepared by a simple solution mixing method, then reduced with hydroiodic acid and cross-linked with glutaraldehyde. Both reduction and cross-linking can improve the tensile strength, but the effect of cross-linking is superior. The improvement of tensile strength is cumulative when reduction and cross-linking are used simultaneously or even successively. Moreover, the order in which these two methods are applied also plays a role; reduction first with cross-linking second shows superior results than the reverse. The tensile strength of the obtained composite film peaked at 112.8 MPa, which is over 7 times that of neat PVA.

Recently, the preparation of flexible graphene-based micro-supercapacitors has attracted considerable attention. In this paper, a flexible and all-solid-state micro-supercapacitor was fabricated by LightScribe technology. Additionally, the influences of the drop-cast amount of graphene oxide (GO) and the numbers of LightScribe times on the performance of the supercapacitor were systematically investigated by means of cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge/discharge. It was determined that the electrochemical performance of the micro-supercapacitor was optimal when the drop-cast amount was 0.38 mg cm−2. Moreover, a positive correlation was found between the capacitance and the number of LightScribe times. The maximum capacitance was 2.9 mF cm−2, which was reached with 20 rounds of LightScribe.

Using supramolecular recognition capability of cucurbit[7]uril to create a novel electrochemical sensing platform was accomplished by self-assembly of cucurbit[7]uril on the surface of graphene–gol...

Based on stepwise deposition of MOF films on a colloid crystal substrate, a strategy for fabricating photonic MOF films was developed. We found that the integration of a photonic structure endows MOF materials with unique optical properties, which can be used as a general and effective transduction scheme for a convenient study of the host–guest chemistry of MOFs.

A rapid and facile method was found to access one-molecule-thick free-standing organic nanosheets in a high yield with controllable size and shape by self-assembly of cucurbit[8]uril and small organic molecules.

Metal–organic frameworks (MOFs) as thin films have gained considerable attention in recent years because of their potential applications in different fields. However, preparation of integrated photonic MOF films still remains a major challenge. This study reports an approach for the fabrication of NH2-MIL-88B photonic films with potential for general application to other MOF films based on the simple spin-coating technique. A systematic study on the effect of MOF suspension concentration, rotation speed, and rotation cycles on the thickness and optical quality of coated films is presented. Moreover, the sensing performance of the NH2-MIL-88B photonic film deposited on a silicon wafer is evaluated using ultraviolet-visible reflection analysis and an optical digital camera, revealing the selective response to various organic vapors. More importantly, such selective sensing behavior can be easily and rapidly visualized by the naked eye.

Heat exchangers are widely used in industry, and analyses and optimizations of the performance of heat exchangers are important topics. In this paper, we define the concept of entropy resistance based on the entropy generation analyses of a one-dimensional heat transfer process. With this concept, a two-stream parallel flow heat exchanger with viscous heating is analyzed and discussed. It is found that the minimization of entropy resistance always leads to the maximum heat transfer rate for the discussed two-stream parallel flow heat exchanger, while the minimizations of entropy generation rate, entropy generation numbers, and revised entropy generation number do not always.

Based on the confinement effect of the CB[8] cavity, a new strategy for explosives detection was developed by using a naphthalene embedded CB[8] complex as receptor. It was found that, dependent on the electronic structures and size of the tested explosives, the trapping of such analytes can significantly influence the photophysical properties of the naphthalene in the CB[8] nanocavity, leading to the direct detection and discrimination of distinctively different groups of trace explosives in the vapor phase, especially including the challenging aliphatic nitro-organics. Control experiments were performed to show the different sensing behaviors between the common organic vapors and nitrate-based explosives, which made it easy to realize the discrimination between target analytes and interferents. Due to the surface attached sensing elements, very fast response and high sensitivity were found in this system. The performed experiments suggested that the naphthalene embedded CB[8]-based sensing protocol opened a new way to develop a new kind of explosive sensor to enable a richer identification of threats.