Search

The intense research activities on the hybrid organic–inorganic perovskites (HOIPs) have led to the greatly improved light absorbers for solar cells with high power conversion efficiency (PCE). How...

Special Chinese propolis sourced from the Changbai Mountains (CBMP) in Northeast China is rich in specific flavonoids and phenolic acids and its bioactivity has not been reported. This study aimed to investigate the antiproliferative effect of CBMP on cancer cells and its molecular mechanisms. Different cancer cell lines were treated with the ethanol extracts of CBMP for 24 hours before the cell viability and mechanism measurements. The results showed CBMP had weak activities against human pancreatic cancer cell PANC1, human lung cancer cell A549, human colon cancer cell HCT116, human liver cancer cell HepG2, human bladder cancer cell T24, and human breast cancer cell MDA-MB-231, but it significantly inhibited the growth of human gastric cancer SGC-7901 cells, caused cell apoptosis and cell cycle arrest in S phase, with increased production of reactive oxygen species (ROS) and reduced mitochondrial membrane potential (MMP). The results indicate that Chinese propolis sourced from the Changbai Mountains selectively inhibits the proliferation of human gastric cancer SGC-7901 cells by inducing both death receptor-induced apoptosis and mitochondria-mediated apoptosis, and cell cycle arrest in S phase. These activities and mechanisms help understand the anticancer action of propolis and its active compounds.

Organic-inorganic hybrid perovskites (OIHPs) hold a great potential for scientific and technological endeavors in the field of ferroelectrics, solar cells, and electroluminescent devices, because of their structural diversity, low cost of manufacture, and ease of fabrication. However, lead iodide perovskite ferroelectrics with narrow band gap have rarely been reported. Here, we present a new two-dimensional (2D) layered lead iodide perovskite ferroelectric, (4,4-DFHHA)

Molecular ferroelectrics are attracting tremendous interest because of their easy and environmental-friendly processing, low acoustic impedance, and mechanical flexibility. Their ferroelectric mechanism is mainly ascribed to the order-disorder transition of molecules such as spherical 1,4-diazabicyclo[2.2.2] octane (DABCO) and quinuclidine. Here, we present two molecular ferroelectrics, [HDABCO][TFSA] and its deuterated one [DDABCO][TFSA] (TFSA = bis(trifluoromethylsulfonyl)ammonium), whose ferroelectricity is triggered by the proton ordering. This is the first time that the protons show a thermally fluctuated bistability with a double-well potential in DABCO-based ferroelectrics. A large deuterium isotope effect (ΔT = ∼53 K) not only proves that they are hydrogen-bonded ferroelectrics but also extends the ferroelectric working temperature range to room temperature. The superfast polarization switching of 100 kHz and ultralow coercive voltage of 1 V (far less than 5 V required for commercially available ferroelectric devices), benefiting from the low energy for proton transfer, allow [DDABCO][TFSA] a great potential for memory devices with low-voltage, high-speed operation. This work should inspire further exploration of hydrogen-bonded molecular ferroelectrics for flexible and wearable devices with the low-power information storage.

Topological defects, such as vortices and skyrmions, provide a wealth of splendid possibilities for new nanoscale devices because of their marvelous electronic, magnetic, and mechanical behaviors. Recently, great advances have been made in the study of the ferroelectric vortex in conventional perovskite oxides, such as BaTiO

Sinomenine (SN) has been used in the clinical treatment of systemic lupus erythematosus and rheumatoid arthritis for many years. Studies showed that SN held protective effects such as anti-inflammation, scavenging free radicals and suppressing immune response in many autoimmune diseases. The purpose of the present study is to explore the mechanism of anti-inflammation of SN on lipopolysaccharide (LPS)-induced macrophages activation and investigate whether the TLR4/NF-κB signaling pathway participated in. Macrophages isolated from mouse peritoneal cavity were stimulated by 1 µg/mL LPS for 24 h. And then the cells were treated with various concentrations of SN, TLR4 inhibitor respectively for additional 48 h. Drug toxicity was detected by MTT assay and Transwell experiment was used to assess chemotaxis. Furthermore, TLR4 and MyD88 mRNA levels were detected by real-time PCR. Western blotting was used to examine TLR4, MyD88 and phosphorylated IκB protein expression in macrophages. Immunofluorescence assay was applied to observe p65 NF-κB protein expression in macrophage nucleus. We extracted macrophages with high purity and activity from the abdominal cavity of mice. SN remarkably inhibited the chemotaxis and secretion function of LPS-stimulated macrophages. It also down-regulated both the protein levels of inflammatory cytokines (TNF-α, IL-1β and IL-6) and the RNA and protein levels of the key factors (TLR4, MyD88, P-IκB) in TLR4 pathway. The expression of p65 NF-κB protein in nuclei was down-regulated, which was correlated with a similar decrease in P-IκB protein level. In conclusion, SN can inhibit the LPS induced immune responses in macrophages by blocking the activated TLR4/NF-κB signaling pathway. These results may provide a therapeutic approach to regulate inflammatory responses.

Piezoelectric sensors that can work under various conditions with superior performance are highly desirable with the arrival of the Internet of Things. For practical applications, a large piezoelectric voltage coefficient g and a high Curie temperature Tc are critical to the performance of piezoelectric sensors. Here, we report a two-dimensional perovskite ferroelectric (4-aminotetrahydropyran)2PbBr4 [(ATHP)2PbBr4] with a saturated polarization of 5.6 μC cm-2, high Tc of 503 K [above that of BaTiO3 (BTO, 393 K)], and extremely large g33 of 660.3 × 10-3 V m N-1 [much beyond that of Pb(Zr,Ti)O3 (PZT) ceramics (20 to 40 × 10-3 V m N-1), more than 2 times higher than that of poly(vinylidene fluoride) (PVDF, about 286.7 × 10-3 V m N-1)]. Combined with the advantages of molecular ferroelectrics, such as light weight, easy and environmentally friendly processing, and mechanical flexibility, (ATHP)2PbBr4 would be a competitive candidate for next-generation smart piezoelectric sensors in flexible devices, soft robotics, and biomedical devices.

A flexible strategy for piezoelectrics Piezoelectric materials produce charge when they are deformed, making them ideal for various types of sensors. However, virtually all piezoelectric materials are ceramics, which are far from ideal for applications requiring flexible sensors. Liao et al. now describe a molecular material with piezoelectric properties comparable to the industry-standard ceramic lead zirconate titanate. The exceptional properties come from finding a molecular solid-solution series that allows for compositional optimization of the piezoelectric properties. Science , this issue p. 1206

The functional performance of food proteins can sometimes be enhanced by forming conjugates or complexes with other food-grade molecules. In this study, the impact of fabrication conditions (pH and mixing ratio) on the formation and properties of phytic acid (PA)-whey protein isolate (WPI) complexes was evaluated. In addition, the ability of the complexes to form and stabilize oil-in-water emulsions was characterized. Emulsions were formed using a high-shear mixer to simulate the production of commercial foods such as dressings and sauces. Most emulsions were highly unstable to creaming due to the relatively large size of the oil droplets they contained (d > 30 μm). Under acidic conditions, emulsions stabilized by PA-WPI complexes were more resistant to creaming and formed thicker cream layers than those stabilized by WPI alone, which was attributed to electrostatic bridging of the cationic protein-coated oil droplets by anionic phytic acid. Evidence for increased droplet-droplet attraction was confirmed by bulk rheology measurements: emulsions stabilized by PA-WPI complexes had a much higher viscosity than those stabilized by WPI. Interfacial tension measurements showed that the PA-WPI complexes adsorbed to an oil-water interface more rapidly than either PA or WPI molecules, as well as producing a greater reduction in interfacial tension. Surface rheology measurements indicated that the dilatational elastic modulus of the interfaces formed by the PA-WPI complexes was less than that formed by WPI alone, indicating that the PA inhibited interfacial protein cross-linking. Our results, indicate that even relatively low PA-to-WPI ratios (1:20) can be used to modulate the physicochemical properties and long-term stability of protein-coated oil droplets, thereby providing an effective strategy for designing food emulsions with improved functionality.

The synergized optimization of water flux and salt rejection by blending with inorganic fillers has been achieved for the polyamide (PA) thin film nanocomposite (TFN) membrane. However, it is difficult to characterize its mass transport properties due to the very thin and heterogeneous PA film. In this work, we select cellulose triacetate (CTA) as the base to prepare hybrid films and their transport properties were studied according to solution-diffusion theory. A series of inorganic fillers, such as reduced graphene oxide (RGO), zeolites, ZIF-8, SiO2 and graphene oxide (GO) were incorporated. The SEM and EDX results indicate a less than 1 wt% filler content for a uniform dispersion. The blending of inorganic fillers leads to enhanced glass transition temperature (Tg) and density, little effect on the water transport property but dramatically decreased salt permeability values, which are nearly ten-fold of that of the CTA film. The blending of GO can densify and hydrophilize CTA simultaneously, which is most promising for a desalination application. The increased water uptake should contribute to its increased water permeability, while the decreased free volume size and FFV value and various interactions between the ions (Na+, Cl-) and GO sheets account for salt permeability decrease.

49 samples of propolis from different regions in China were collected and analyzed for their chemical compositions, contents of total flavonoids (TFC), total phenolic acid (TPC) and antioxidant activity. High-performance liquid chromatography (HPLC) analysis identified 15 common components, including key marker compounds pinocembrin, 3-O-acetylpinobanksin, galangin, chrysin, benzyl p-coumarate, pinobanksin and caffeic acid phenethyl ester (CAPE). Cluster analysis (CA) and correlation coefficients (CC) analysis showed that these propolis could be divided into three distinct groups. Principal component analysis (PCA) and multiple linear regression analysis (MLRA) revealed that the contents of isoferulic acid, caffeic acid, CAPE, 3,4-dimethoxycinnamic acid, chrysin and apigenin are closely related to the antioxidant properties of propolis. In addition, eight peak areas decreased after reacting with 1,1-Diphenyl-2-picrylhydrazyl (DPPH) radicals, indicating that these compounds have antioxidant activity. The results indicate that the grouping and spectrum&ndash, effect relationship of Chinese propolis are related to their chemical compositions, and several compounds may serve as a better marker for the antioxidant activity of Chinese propolis than TFC and TPC. The findings may help to develop better methods to evaluate the quality of propolis from different geographic origins.

TMAB001 is a humanized rabbit monoclonal antibody (mAb) designed to bind and neutralize human vascular endothelial growth factor (VEGF)-165. The purpose of the study was to investigate the pharmacokinetics (PK) and ocular tissue distribution after a single intravitreal (IVT) dose in rabbits and monkeys. Rabbits (2.5 mg/eye; n = 40) and monkeys (2.5 mg/eye; n = 12) received TMAB001 as a bilateral IVT dose. TMAB001 concentrations were measured in ocular tissues in all rabbits and monkeys by enzyme-linked immunosorbent assay (ELISA). TMAB001 and VEGF concentrations were measured in serum of monkeys by ELISA. Following a single bilateral IVT injection of TMAB001 2.5 mg/eye, the highest concentration was in vitreous humor, followed by retina and choroid, and the lowest concentration was in lens. In rabbits, TMAB001 was still detectable in ocular tissues at day 21 after single IVT dose, with the highest level in the vitreous humor and then retina, with longest t1/2 in aqueous humor and shortest t1/2 in choroid. In monkeys, tmax in serum was 43 h and t1/2 was approximately 5.5 days. Cmax in serum was much lower than that in vitreous, nearly 1/200. After IVT injection of TMAB001, total VEGF concentrations in serum and ocular tissues increased over time. VEGF concentration in retina and choroid increased over time, up to 336 h after administration. This study demonstrated that TMAB001 could reach the drug target sites-retina and choroid after a single bilateral IVT administration in rabbits and monkeys, with a long t1/2 in vitreous humor. TMAB001 also showed strong capability to neutralize VEGF. The study further confirmed that full-length antibodies can also efficiently diffuse and distribute in ocular tissues.

After decade’s development, Raman spectroscopy is now one of the routine spectral tools for its non-destructive, minimum sample preparation and capabilities in probing the information of the crystalline order, chemical composition, strain/stress, temperature and even electronic properties. With the help of the development of the microscopic instrument, the sensitivity and precision of Raman spectroscopy receive great improvement. This thesis is devoted to two aspects of the Raman spectroscopy: 1). the improvement of the Raman spectroscopy featuring researches on the advanced Raman spectroscopy/imaging techniques; 2). the application of Raman spectroscopic studies on the rapid developing carbon-based nano-materials, e.g. carbon nanotubes and graphene. DOCTOR OF PHILOSOPHY (SPMS)

Though dominating most of the practical applications, inorganic ferroelectric thin films usually suffer from the high processing temperatures, the substrate limitation, and the complicated fabrication techniques that are high-cost, energy-intensive, and time-consuming. By contrast, molecular ferroelectrics offer more opportunities for the next-generation flexible and wearable devices due to their inherent flexibility, tunability, environmental-friendliness, and easy processability. However, most of the discovered molecular ferroelectrics are uniaxial, one major obstacle for improving the thin-film performance and expanding the application potential. In this Perspective, we overview the recent advances on multiaxial molecular ferroelectric thin films, which is a solution to this issue. We describe the strategies for screening multiaxial molecular ferroelectrics and characterizations of the thin films, and highlight their advantages and future applications. Upon rational and precise design as well as optimizing ferroelectric performance, the family of multiaxial molecular ferroelectric thin films surely will get booming in the near future and inject vigor into the century-old ferroelectric field.

Micropollutants (MPs) present in water have shown increasing threat on the ecosystem. Membrane adsorption is playing an increasingly important role on the MPs removal but the synthesis of adsorptive membrane of high capacity remains challenging. This work proposed a strategy of grafting mesoporous nanoparticles onto macroporous membranes to prepare sorbents for MPs removal. The SiO2 nanoparticles with thiol groups (SiO2-SH) was introduced onto the RC membrane surface to prepare RC-SH membrane with a hierarchical porous structure. Specific adsorptive ligands, including itaconic acid (IA) or glycidol, was then immobilized to the RC-SH membrane surface via the thio-ene and thio-epoxy chemistry towards RC-IA and RC-PG membranes. Three kinds of adsorption membranes were obtained and their physical–chemical structure and morphologies were characterized by ATR-FTIR, XPS, SEM and BET. The grafted nanoparticles have been demonstrated to increase the surface area of the adsorptive membranes. The obtained adsorptive membranes, RC-SH, RC-IA, and RC-PG, show good adsorptive capacity for Hg(II) (179.0 mg/g) , Pb(II) (140.1 mg/g), and boron (2.55 mmol/g). The adsorption isotherm and kinetics fit well with Langmuir model and pseudo-second-order kinetic model, respectively. This work provides a universal method tethering porous nanoparticles onto the macroporous membrane surface for improved functionality capacity.

Inspired by the enhancement of the desalination performance of polyamide membranes upon controlled chlorination, chlorination was applied to the polybenzimidazole (PBI) membrane hoping to improve its desalination performance. Chlorination was conducted at three pHs (4,7,10) with chlorination density up to 50,000 ppm*h via a simple soaking treatment. The structure and physicochemical changes caused by the hypochlorite treatment were characterized by SEM, AFM, XPS, FTIR and XRD. After chlorination, the morphologies did not change significantly. But the Cl element was incorporated onto polymer chains, leading to the scission of intermolecular hydrogen bond and denser packing of PBI chains. Simultaneously, the C O group emerged after chlorination, indicating ring opening of imidazole in polymer backbone. More severe damage occurs at pH 4 with more chlorine introduction, which is due to the strong oxidizability of abundant chlorine or hypochlorous acid in acid solution, while chlorination at pH 10 mostly promotes imidazole hydrolysis. Chlorination mostly alter PBI permeation properties by altering its diffusion properties, with significant enhancement of water diffusion but minimal change on salt diffusion. This result should be due to the dense packing of PBI chains. After chlorination at pH 10, the salt permeability even slightly decreased owing to the dense packed polymer chains and the electrostatic repulsion of charged membrane formed by hydrolysis. As a result, chlorination can increase the diffusion selectivity of water/salt increased by an order of magnitude, as well as the water/salt permselectivity without sacrificing the water permeability. Chlorination at basic pH especially has a positive effect on PBI membrane with improved selectivity for desalination process and sustained mechanical strength.

1T-TiSe 2 is a model transition metal dichalcogenide material that develops charge density waves (CDWs). Here we present variable-temperature Raman spectroscopy study on both CDW and optical phonon modes of 1T-TiSe 2 thin layers exfoliated onto SiO 2 substrate. Raman scattering intensities of all modes reach a maximum when the sample thickness is about 12 nm. This phenomenon can be explained by optical interference effect between the sample and the substrate. The CDW amplitude modes experience redshift and broadening as temperature increases. We extract CDW transition temperature ( T CDW ) from temperature dependence of the frequency of A 1 g CDW mode. We find that T CDW decreases in thinner flakes, which could be due to extrinsic effects.

The classical organic ferroelectric, poly(vinylidene fluoride) (PVDF), has attracted much attention as a promising candidate for data storage applications compatible with all-organic electronics. However, it is the low crystallinity, the large coercive field, and the limited thermal stability of remanent polarization that severely hinder large-scale integration. In light of that, we show a molecular ferroelectric thin film of [Hdabco][ReO4] (dabco = 1,4-diazabicyclo[2.2.2]octane) (1), belonging to another class of typical organic ferroelectrics. Remarkably, it displays not only the highest Curie temperature of 499.6 K but also the fastest polarization switching of 100k Hz among all reported molecular ferroelectrics. Combined with the large remanent polarization values (∼9 μC/cm2), the low coercive voltages (∼10 V), and the unique multiaxial ferroelectric nature, 1 becomes a promising and viable alternative to PVDF for data storage applications in next-generation flexible devices, wearable devices, and bio...

GLP-1-based strategies have many advantages in treatment of type 2 diabetes mellitus (T2DM), but native GLP-1 has a short half-life in the circulation, which limits its clinical application. The purpose of this study was to evaluate the effects of GW002, a novel recombinant GLP-1 analog fusion protein produced by linking the human GLP-1 analog C-terminus to the N-terminus of human serum albumin via a linker, in vitro and in BKS-db mice. To determine whether GW002 can activate the GLP-1 receptor in cells, the level of luciferase expression was evaluated in vitro. In vivo, body weight, food intake, non-fasting and fasting blood glucose, oral glucose tolerance test, blood glucose and insulin levels, liver histology, liver function parameters and antibody levels in BKS-db mice were investigated to evaluate the effects of GW002. Albiglutide was chosen as a positive comparator. Cyclic adenosine monophosphate levels were increased in a dose-dependent manner in cells. In vivo studies demonstrated that GW002 lowers non-fasting and fasting blood glucose levels and improves glucose tolerance and insulin secretion in BKS-db mice. The degree of hepatic steatosis and hepatic biochemical indexes was also decreased. In this study, the mice body weight was not reduced significantly. The above results showed that the efficacy of GW002 in BKS-db mice displayed a significant hypoglycemic effect, which indicated that GW002 might be a potential candidate for the treatment of T2DM.

Ferroelectric thin-films are highly desirable for their applications on energy conversion, data storage and so on. Molecular ferroelectrics had been expected to be a better candidate compared to conventional ferroelectric ceramics, due to its simple and low-cost film-processability. However, most molecular ferroelectrics are mono-polar-axial, and the polar axes of the entire thin-film must be well oriented to a specific direction to realize the macroscopic ferroelectricity. To align the polar axes, an orientation-controlled single-crystalline thin-film growth method must be employed, which is complicated, high-cost and is extremely substrate-dependent. In this work, we discover a new molecular ferroelectric of quinuclidinium periodate, which possesses six-fold rotational polar axes. The multi-axes nature allows the thin-film of quinuclidinium periodate to be simply prepared on various substrates including flexible polymer, transparent glasses and amorphous metal plates, without considering the crystallinity and crystal orientation. With those benefits and excellent ferroelectric properties, quinuclidinium periodate shows great potential in applications like wearable devices, flexible materials, bio-machines and so on., Molecular ferroelectric crystals hold promise in data storage applications, yet their preparations by maximizing molecular polarization are challenging. Here, You et al. report quinuclidinium periodate with six rotation axes and grow them in macroscopic ferroelectric thin films via a solution process.

It is known that CH3NH3PbI3 is particularly promising for next-generation solar devices; therefore, molecular perovskite structures have recently received extraordinary attention from the academic community because of their potential in producing unique physical properties. However, although great efforts have been made, molecular ferroelectrics with three-dimensional (3D) perovskite structures are still rare. So far, reported perovskite-like molecular ferroelectrics are basically one- or two-dimensional, significantly deviating from the inorganic perovskite ferroelectrics. Thus, their ferroelectric properties have to be greatly improved to meet the requirements of practical applications. Here, we report a 3D molecular perovskite ferroelectric: (3-ammoniopyrrolidinium)RbBr3 [(AP)RbBr3], with a high Curie temperature (Tc = 440 K) beyond that of BaTiO3. To the best of our knowledge, such above-room-temperature ferroelectricity in the 3D molecular perovskite compound is unprecedented. Furthermore, (AP)RbBr3 ...

Molecular ferroelectrics are attracting much attention as valuable complements to conventional ceramic ferroelectrics owing to their solution processability and nontoxicity. Encouragingly, the recent discovery of a multiaxial molecular ferroelectric, tetraethylammonium perchlorate, is expected to be able to solve the problem that in the technologically relevant thin-film form uniaxial molecular ferroelectrics have been found to perform considerably more poorly than in bulk. However, it can show good polarization–electric field (P–E) hysteresis loops only at very low frequency, severely hampering practical applications such as ferroelectric random access memory. Here, we present a biaxial molecular ferroelectric thin film of [Hdabco]ClO4 (dabco = 1,4-diazabicyclo[2.2.2]octane) (1), where a perfect ferroelectric hysteresis loop can be observed even at 10 kHz. It is the first example of a molecular ferroelectric thin film whose polarization can be switched at such a high frequency. Moreover, using piezorespo...

Besides the single crystals, ferroelectric materials are actually widely used in the forms of the polycrystals like ceramics. Multiaxial ferroelectrics with multiple equivalent polarization directions are preferable for such applications, because more equivalent ferroelectric axes allow random spontaneous polarization vectors to be oriented along the electric field to achieve a larger polarization after poling. Most of ceramic ferroelectrics like BaTiO3 have equivalent ferroelectric axes no more than three. We herein describe a molecular-ionic ferroelectric with 12 equivalent ferroelectric axes: tetraethylammonium perchlorate, whose number of axes is the most in the known ferroelectrics. Appearance of so many equivalent ferroelectric axes benefits from the plastic phase transition, because the plastic phase usually crystallizes in a highly symmetric cubic system. A perfect macroscopic ferroelectricity can be obtained on the polycrystalline film of this material. This finding opened an avenue constructing ...

A series of stimuli-responsive reverse (RO) membranes were prepared by tethering three stimuli-responsive polymers, poly (sulfobetaine methacrylate) (PSBMA), poly (4-(2-Sulfoethyl)-1-(4-vinyl-benzyl) pyridinium betain) (PSVBP) and poly (N-isopropylacrylamide) (PNIPAM) onto the surface of a commercial thin-film (TFC) RO membrane via surface-initiated graft polymerization. The membrane surface was characterized by ATR-FTIR, XPS, zeta potential, water contact angle (WCA), FESEM and AFM. Membrane characterization indicates successful grafting of these polymers, with more negatively-charged, smoother and more hydrophilic surfaces as a result. Long-term fouling-rinsing cycled experiments were conducted to evaluate fouling resistance and cleaning efficiency. With CaCO 3 as the foulant, the modified membranes showed better fouling resistance in the whole testing as long as 320 h; with BSA as the foulant, they only showed better antifouling performance in short term. However, the modified membranes showed much higher cleaning efficiency in both cases, with the PA-g-PSVBP membrane as the best one.

Current MOF composite membranes usually suffer from unduly thick MOF layers and poor adhesion with the polymer substrate. We prepared a thin MOF film (440 nm) on a polymer support with 2-D MOF nanosheets as seeds via a layer-by-layer growth. These 2-D MOF seeds not only provided bonding between the MOF film and the polymer substrate but also facilitated the formation of a continuous and defect-free MOF membrane, which demonstrated excellent performance in gas separation.

The X-site ion in organic-inorganic hybrid ABX3 perovskites (OHPs) varies from halide ion to bridging linkers like HCOO- , N3- , NO2- , and CN- . However, no nitrite-based OHP ferroelectrics have been reported so far. Now, based on non-ferroelectric [(CH3 )4 N][Ni(NO2 )3 ], through the combined methodologies of quasi-spherical shape, hydrogen bonding functionality, and H/F substitution, we have successfully synthesized an OHP ferroelectric, [FMeTP][Ni(NO2 )3 ] (FMeTP=N-fluoromethyl tropine). As an unprecedented nitrite-based OHP ferroelectric, the well-designed [FMeTP][Ni(NO2 )3 ] undergoes the ferroelectric phase transition at 400 K with an Aizu notation of 6/mmmFm, showing multiaxial ferroelectric characteristics. This work is a great step towards not only enriching the molecular ferroelectric families but also accelerating the potential practical applications.

Molecular ferroelectrics are attracting tremendous interest because of their low cost, mechanical flexibility, easy processing, low weight, and low acoustical impedance. Moreover, their combination of ferroelectric and optical properties has led to investigations of their many potential applications, such as low-energy electron excitation and field emission displays. However, luminescent molecular ferroelectrics have rarely been reported, except for several AMnX3-type or lanthanide ion-based luminescent ferroelectrics. Here, we report the first above-room-temperature phosphonium-based molecular ferroelectric perovskite, [(CH3)4P]CdCl3 (1), with a high Curie temperature (Tc = 348 K) and moderate remanent polarization (Pr = 0.43 μC/cm2). Using piezoresponse force microscopy (PFM), the typical stripe-like domains of ferroelectrics can be observed. Moreover, 1 exhibits orange luminescence under UV excitation after doping with Sb3+, which represents a first step toward realizing luminescence-enhanced molecular ferroelectrics with various wavelengths. These results will inspire the further exploration of phosphonium-based ferroelectrics and pave the way toward practical applications in ferroelectric luminescence and/or multifunctional devices. A molecule that can be manipulated with electric fields while simultaneously acting as a light-emitting phosphor could find use in next-generation photovoltaics. Ferroelectric materials are positively charged on one end and negatively on the other. Recent work suggests that the spontaneous dipoles formed by these charges can help engineer high outputs in solar cells. Lin Zhou from Southeast University in Nanjing, China, and colleagues have developed a ferroelectric with improved characteristics for device manufacturing. The team combined organo-phosphorus cations with trichlorocadmate anions to produce an organic–inorganic composite that can be synthesized at room temperature, instead of the energetically intense conditions needed for conventional all-inorganic ferroelectrics. Adding small portions of antimony ions to the molecule generated strong luminescent emissions that may be used to concentrate and direct solar radiation. A phosphonium-based perovskite, [(CH3)4P]CdCl3, is designed and synthesized, which shows ferroelectric characteristics below 348 K as revealed by the observation of typical stripe-like domains and hysteresis loops. By doping with Sb3+, this material exhibits orange luminescence under UV excitation. This work will open new avenues in designing multifunctional luminescent molecular ferroelectrics.

The relationship between desalting membrane and its water/salt transport properties remain largely unknown. This is especially true for polyamide thin film nanocomposite (TFN) membranes which have shown excellent desalination performance and attracted booming attention in recent years. Considering cellulose triacetate (CTA) can be made into dense membranes whose transport properties can be measured based on the solution-diffusion theory, we systematically study the water/salt transport property of the CTA nanocomposite membranes blended with reduced graphene oxide (rGO) of varying reduction degrees, with multilayer graphene oxide (MGO) and single layer graphene oxide (SGO) as control samples. The nanocomposite membranes show enhanced membrane density and glass transition temperature (Tg) due to the interaction of the polar group in GO/rGO with CTA chains. The GO (rGO) frustrates the polymer chain packing and decreases crystallinity of CTA membrane. The adding of rGO increases the water permeability by increasing its diffusivity due to the decreased crystallinity and additional channel from (r)GO, but decreases the salt permeability by decreasing its diffusivity due to membrane densification and the interactions of ions with GO/rGO. The water permeability and diffusivity of the nanocomposites increase when its water sorption decreases, which is against the trend of pure polymers, presumably due to the fact that water sorption is not a good reflection of the free volume in this heterogeneous membrane. Meanwhile, the GO/rGO blending slightly increases water sorption without changing the salt sorption because the newly-introduced polar groups in GO/rGO traps water and suppress its solvation capacity for salt. Both the water permeability and the water/salt selectivity increase with the reduction degree due to the decreased water transport resistance.

The electrical performance of two dimensional transitional metal dichalcogenides (TMDs) is strongly influenced by the amount of structural defects inside. In this work, we provide an optical spectroscopic characterization approach to correlate the amount of structural defects and the electrical performance of WSe2 devices. Low temperature photoluminescence (PL) spectra of electron beam lithography (EBL) processed WSe2 presents a clear defect-induced PL emission due to excitons bound to defects, which would strongly degrade the electrical performance. By adopting an e-beam-free transfer-electrode technique, we are able to prepare backgated WSe2 device with limited amount of defects. A maximum hole-mobility of about 200 cm2/Vs was achieved due to reduced scattering sources, which is the highest reported value among its type. This work would not only provide a versatile and nondestructive method to monitor the defects in TMDs, but also a new route to approach the room temperature phonon-limited mobility in high performance TMDs devices., Comment: 22 pages, 10 figures, to appear in Nano Research

A novel positive-charged polyamine-based cyclophosphazene nanofiltration membrane (NF) was prepared via interfacial polymerization between branched polyethyleneimine (PEI) and hexachlorocyclotriphosphazene (HCCP). The composite membranes were characterized using ATR-FTIR, XPS, SEM, AFM, water contact angle, and zeta potential analysis. The membrane with optimal performance was prepared by interfacial reaction with 5 wt% PEI (Mn = 600 g/mol) in aqueous phase, 1 wt% HCCP in organic phase, 5 min dwell time, and 15 min curing time at 100 °C. The resultant membrane has a 97% rejection to MgCl2 and a water permeation of 55 L/m2 h when testing at 1.5 MPa and 25 °C with a 1000 ppm salt solution. The results for filtrating various dyes showed that the PEI/HCCP membrane could remove small organic compounds and contaminants. Antibacterial assay results indicated that the membrane had a nearly 100% bacterial inhibitate rate against both Gram-negative E. coli and Gram-positive S. aureus. In addition, all bacteria in a concentrated suspension (107 CFU/mL) could be completely eliminated within 20 min contacting with the PEI/HCCP membrane. Finally, a 140 h cross-flow testing indicates an excellent membrane performance stability.

Molecular piezoelectrics are attracting tremendous interest because of their easy processing, light weight, low acoustical impedance, and mechanical flexibility. However, reports of molecular piezoelectrics with a piezoelectric coefficient d33 comparable to piezoceramics such as barium titanate (BTO, 90–190 pC/N) have been scarce. Here, we present a uniaxial molecular ferroelectric, trimethylchloromethylammonium tribromocadmium(II) (TMCM-CdBr3), in which the halogen bonding might be a possible critical point for the stabilization of one-dimensional (1D) {CdBr3}− chain and further reservation of its ferroelectricity in such organic–inorganic hybrid crystalline systems. It has a large d33 of 139 pC/N, 1 order of magnitude higher than those of most classically uniaxial ferroelectrics such as LiNbO3 (6–16 pC/N) and Rochelle salt (∼7 pC/N), and comparable with those of multiaxial ferroelectrics such as BTO and trimethylbromomethylammonium tribromomanganese(II) (112 pC/N). Moreover, the simple single-crystal gr...

Inorganic perovskite ferroelectrics are widely used in nonvolatile memory elements, capacitors, and sensors because of their excellent ferroelectric and other properties. Organic ferroelectrics are desirable for their mechanical flexibility, low weight, environmentally friendly processing, and low processing temperatures. Although almost a century has passed since the first ferroelectric, Rochelle salt, was discovered, examples of highly desirable organic perovskite ferroelectrics are lacking. We found a family of metal-free organic perovskite ferroelectrics with the characteristic three-dimensional structure, among which MDABCO ( N -methyl- N9 -diazabicyclo[2.2.2]octonium)–ammonium triiodide has a spontaneous polarization of 22 microcoulombs per square centimeter [close to that of barium titanate (BTO)], a high phase transition temperature of 448 kelvins (above that of BTO), and eight possible polarization directions. These attributes make it attractive for use in flexible devices, soft robotics, biomedical devices, and other applications.

Piezoelectric materials have been widely used in various applications, such as high-voltage sources, actuators, sensors, motors, fre-quency standard, vibration reducer, and so on. In the past decades, lead zirconate titanate (PZT) binary ferroelectric ceramics have dominated the commercial piezoelectric market due to their excellent properties near the morphotropic phase boundary (MPB), although they contain more than 60% toxic lead element. Here, we report a lead-free and one-composition molecular ferroelectric trimethylbromomethylammonium tribromomanganese (ΙΙ) (TMBM-MnBr3) with a large piezoelectric coefficient d33 of 112 pC/N along polar axis, comparable with those of typically one-composition piezoceramics such as BaTiO3 along polar axis [001] (~90 pC/N) and much greater than those of most known molecular ferroelectrics (almost below 40 pC/N). More significantly, the effec-tive local piezoelectric coefficient of TMBM-MnBr3 films is comparable to that of its bulk crystals. In terms of ferroelectric pe...

Recently, a plastic crystal of quinuclidinium perrhenate (${\mathrm{HQReO}}_{4}$) was reported to have the feasibility of controlling the crystallographic orientation in the grown crystal, but the corresponding temperature window is only about 22 K (345--367 K). Such a narrow window and uncertain ferroelectricity at room temperature would extremely limit its application potential. In this report, we prepared a large area high-quality polycrystalline thin film of ${\mathrm{HQReO}}_{4}$ and for the first time observed ferroelectricity in the temperature range from 298 to 367 K. Density functional theory calculations revealed the origin of room-temperature ferroelectricity is ascribed to the collaborative flipping of HQ (protonated quinuclidine) and ${\mathrm{ReO}}_{4}^{\ensuremath{-}}$, which is dynamically preferred in the presence of a $\mathrm{N}─\mathrm{H}\ensuremath{\cdots}\mathrm{O}$ hydrogen bond. A local piezoresponse force microscopy measurement was also employed to study the mechanisms of multiaxial polarization rotation and domain dynamics. By extending the ferroelectric temperature window to room temperature and the extraordinary thin-film processability, ${\mathrm{HQReO}}_{4}$ would certainly become a suitable candidate for next generation ferroelectric materials.

The process of molecular recognition is the assembly of two or more molecules through weak interactions. Information in the process of molecular recognition can be transmitted to us via physical signals, which may find applications in sensing and switching. The conventional signals are mainly limited to light signal. Here, we describe the recognition of diols with Cu(1,10-phenlothroline)2SeO4 and the transduction of discrete recognition events into dielectric and/or ferroelectric signals. We observe that systems of Cu(1,10-phenlothroline)2SeO4·(diol) exhibit significant dielectric and/or ferroelectric dependence on different diol molecules. The compounds including ethane-1,2-diol or propane-1,2-diol just show small temperature-dependent dielectric anomalies and no reversible polarization, while the compound including ethane-1,3-diol shows giant temperature-dependent dielectric anomalies as well as ferroelectric reversible spontaneous polarization. This finding shows that dielectricity and/or ferroelectricity has the potential to be used for signalling molecular recognition., Molecular recognition is an important biological process where guest and host molecules interact through non-covalent bonding. Ye et al. show that this can be sensed by the dielectric and ferroelectric signals of the final complexes in a series of metal-coordination compounds with different diol molecules.

Finding a more flexible mechanical sensor Piezoelectric materials allow conversion between electricity and mechanical stresses. The most efficient piezoelectric materials are ceramics such as BaTiO 3 or PbZrO 3 , which are also extremely stiff. You et al. identified an organic perovskite structured piezoelectric material that is far more pliable yet has a piezoelectric response similar to that of traditional ceramics. This material may be a better option to use as a mechanical sensor for flexible devices, soft robotics, biomedical devices, and other micromechanical applications that benefit from a less stiff piezoelectric material. Science , this issue p. 306

We studied the far-field optical reflection contrast spectroscopy (FORCS) properties of the following system: individual Au nanospheres (radius R) immobilized above Si substrate with different thicknesses (d) SiO2 between them. We found that peaks in the FORCS red-shift exponentially with d decreasing. The near-field coupling between the Au nanosphere and its supporting substrate is revealed to contribute to this, while the coupling strength is demonstrated to decrease exponentially with a decay length of 0.30 in units of d/R. It qualitatively agrees well in magnitude with the near-field coupling between two noble metal nanoparticles consisting of a dimer. Our results demonstrate that the FORCS can provide insight into the near-field coupling, which is significant for their applications in nano-photonics, sensing, surface-enhanced spectrascopies, etc.

Polyurethane (PU) composite foam containing microencapsulated phase change materials (MicroPCMs) was fabricated by adding heat-treated microencapsulated n -octadecane in reactants. The microcapsules are evenly inserted inside the foam. The composite foam absorbs heat energy at approximately 31 °C, and releases heat energy at approximately 28 °C. The enthalpy of the foam rises with the increase of the content of MicroPCMs. It is above 12 J/g for the foam containing 12.59 wt% MicroPCMs. The addition of MicroPCMs has no significant influence to the thermal stability of polyurethane foam.

Coupling of ferroelectricity and optical properties has become an interesting aspect of material research. The switchable spontaneous polarization in ferroelectrics provides an alternative way to manipulate the light-matter interaction. The recent observation of strong photoluminescence emission in ferroelectric hybrid organic-inorganic compounds, (pyrrolidinium)MnX3 (X = Cl or Br), is an attractive approach to high efficiency luminescence with the advantages of ferroelectricity. However, (pyrrolidinium)MnX3 only displays ferroelectricity near or below room temperature, which limits its future applications in optoelectronics and multifunctional devices. Here, we rationally designed and synthesized high-temperature luminescent ferroelectric materials. The new hybrid compound (3-pyrrolinium)MnCl3 has a very high Curie temperature, Tc = 376 K, large spontaneous electronic polarization of 6.2 μC/cm(2), and high fatigue resistance, as well as high emission efficiency of 28%. This finding is a further step to the practical use of ferroelectric luminescence based on organic-inorganic compounds.

Two-dimensional (2D) molybdenum disulfide (MoS2) is considered as a promising candidate for electronic and optoelectronic devices. However, structural defects in MoS2 are widely reported and can greatly degrade its electrical and optical properties. In this work, we investigate the structural defects in MoS2 by low temperature photoluminescence (PL) spectroscopy and study their effects on the electrical performance, i.e. carrier mobility. We also adopt the mild oxygen plasma treatment to repair the structural defects and found that the carrier mobility of monolayer MoS2 can be greatly improved. This work would therefore offer a practical route to improve the performance of 2D dichalcogenide-based electrical and optoelectronic devices.

A precolumn enzyme reactor containing beta-glucosidase immobilized on LC-NH2 packed-material beads was used on-line with HPLC for determining the glucuronide/sulphate metabolites of benzene. After dilution with phosphate buffer (pH 6.8), the urine sample was injected into the HPLC system directly. Subsequently, after hydrolysis of the conjugates, phenol was produced in the enzyme reactor and was separated from other urinary components on a reversed-phase C18 column with fluorescence detection. A switching valve assembly was used to control the passage of the sample and the eluent into the reactor to prevent damage to the enzyme by the elution solvent. Factors affecting the enzymatic hydrolysis were investigated. The proposed method provides a simple and rapid procedure for urinary phenol determination. The calibration graph was linear in the range 0.25-5.0 ppm with a good correlation coefficient (r = 0.999), and in the range 0.05-1.0 ppm with r = 0.981. The detection limit was 10 ppb and the relative standard deviation was less than 2.27%. Application of the method is illustrated by the analysis of a urine sample collected from a gas station worker.

The optical near-field enhancement induced by coupling between noble nanoparticles and the substrate has been studied by a far-field imaging method. The longitudinal mode of the incident laser is revealed to contribute to the coupling. The far-field images of individual gold nanoparticles exhibit a peanut-shaped pattern; these were constructed by the intensity of inelastically scattered light. The coupling between gold nanoparticles and the silicon substrate leads to the patterned image. By tuning the separation between the gold nanoparticles and substrate using SiO(2) layers of different thickness, the coupling efficiency decreases with the thickness of the SiO(2) layer.