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Herein, a core–shell nanocomposite was fabricated by self-assembly of the photo-responsive copolymer with silica-coated upconversion nanoparticles for near-infrared light-controlled drug release and cancer therapy. Firstly, lanthanide upconversion nanoparticles (UCNPs) co-doped with Yb3+ and Tm3+ were encapsulated with mesoporous silica as the core (MUCNPs). Then a folate conjugated light-responsive copolymer (PSMN-FA) was synthesized and coated on MUCNP as the shell via self-assembly. Anti-cancer drugs could be loaded into the mesopores of the silica layer before polymer coating. Upon near-infrared (NIR) light irradiation at 980 nm, the caged UCNPs emitted luminescence in the UV region, which could change the structure of the amphiphilic copolymer and separate it from the MUCNPs, immediately followed by the release of the pre-loaded drugs to the targeted cancer cells. Our model experiments in vitro verified that the nanocarrier MUCNPs@C18@PSMN-FAcan provide active tumor targeting to folate receptor over-expressed (FR+) tumor cells. Both in vitro and in vivo studies were carried out to evaluate the NIR-controlled drug release strategy and the promising application in anticancer therapy based on the polymer-UCNPs nanocomposites.

In this paper, two molecules (E)-6,6′-bis(benzo[b]thiophen-2-yl)-1,1′-bis(2-ethylhexyl)-[3,3′-biindolinylidene]-2,2′-dione (ID(BT)2) and (E)-6,6′-di(benzofuran-2-yl)-1,1′-bis(2-ethylhexyl)-[3,3′-biindolinylidene]-2,2′-dione (ID(BF)2) were designed and synthesized, in which isoindigo acted as the electron acceptor and benzoheterocycles acted as electron donors. The result illustrated that as the heteroatom in the benzoheterocycle was changed from O to an S atom, the intramolecular dihedral angle enlarged from 0.3° to 23°. The ID(BT)2 based device exhibited SRAM memory characteristics and the ID(BF)2 based device exhibited DRAM behaviour. The enlarged dihedral angle would prolong the process of moving back the excited electrons in the LUMO energy level to the original HOMO energy level; in other words, the ON state of the ID(BT)2 based device needs more time to return to the original OFF state and thus to exhibit SRAM performance. ID(BF)2 is almost planar and has a small barrier to impede the excited electrons from recovering to the original state, therefore the ID(BF)2 based device could return back to the OFF state in a very short time and exhibited DRAM characteristics. This is a new viewpoint for achieving different types of memory devices through changing the steric geometry and improving the intramolecular dihedral angle to impede the charge transferability.

In the past several decades, a great deal of attention has been focused on the control of light emission of luminescent materials. Compared to our previous work on an aggregation-induced emission (AIE) initiator, an aggregation-caused quenching (ACQ) initiator (TPP-A) has been successfully synthesized and acted as an initiator of atom transfer radical polymerization (ATRP). Four end-functionalized polymers, PS-A, PS-NI, PNIPAM-A and PNIPAM-NI, were obtained using TPP-A or TPP-NI as an initiator via ATRP. TPP-A exhibits a weak charge transfer (CT) and ACQ, but TPP-NI possesses a strong CT and AIE. After two initiators were introduced to polystyrene (PS) chains, the CT of PS-A and PS-NI are well-preserved, but their photoluminescence (PL) intensity is increased because the PS chains could separate initiators from intermolecular interactions and restrict their intramolecular rotations. However, the emission behaviours of PNIPAM-A are different from those of PS-A due to the high polarity of the PNIPAM chain. When the temperature of the solution for PNIPAM-A is above the lower critical solution temperature (LCST), the PNIPAM-A solution possessed higher emission intensities than those measured at room temperature due to the decrease the polarity of the PNIPAM chain and the emission behaviours of PNIPAM-NI are similar to that of PS-NI.

Nowadays, among the many heavy metal pollutants, hexavalent chromium (Cr(VI)) seriously threatens ecological systems and human health due to its high solubility, acute toxicity and potential carcinogenicity in wastewater. Meanwhile, semiconductor photocatalytic reduction is continuously gaining increasing significant research attention in the treatment of Cr(VI). Hence, we report an efficient preparation method for SnS

Herein, for the first time, quaternary resistive memory based on an organic molecule is achieved via surface engineering. A layer of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT-PSS) was inserted between the indium tin oxide (ITO) electrode and the organic layer (squaraine, SA-Bu) to form an ITO/PEDOT-PSS/SA-Bu/Al architecture. The modified resistive random-access memory (RRAM) devices achieve quaternary memory switching with the highest yield (∼41%) to date. Surface morphology, crystallinity, and mosaicity of the deposited organic grains are greatly improved after insertion of a PEDOT-PSS interlayer, which provides better contacts at the grain boundaries as well as the electrode/active layer interface. The PEDOT-PSS interlayer also reduces the hole injection barrier from the electrode to the active layer. Thus, the threshold voltage of each switching is greatly reduced, allowing for more quaternary switching in a certain voltage window. Our results provide a simple yet powerful strategy as an alternative to molecular design to achieve organic quaternary resistive memory.

Smart surfaces with controllable wettability have attracted substantial interest owing to the potential use of these materials for the separation of oil from oily water caused by frequent oil-spill accidents. Because there are few separation materials on the market that are capable of switching between hydrophobicity and hydrophilicity, this work reports an efficient and low-cost method to fabricate a photoresponsive membrane through the sulfur(VI) fluoride exchange reaction (SuFEx) between poly(4-vinylphenol sulfofluoridate) and (E)-1-(4-(tert-butoxy)phenyl)-2-(4-(trifluoromethoxy)phenyl)diazene. The resulting material displays switchable wettability between hydrophobic and hydrophilic states when subjected to ultraviolet or visible irradiation. This membrane can be recycled (greater than five times) and features superior efficiency (up to 97.9 %) for the separation of oils that have both higher and lower densities than water. This work is the first proof-of-concept application of SuFEx to fabricate functional materials for environmental remediation.

Adsorption and improved biodegradation of dyes in wastewater was achieved with Fe

Organic multilevel random resistive access memory (RRAM) devices with an electrode/organic layer/electrode sandwich-like structure suffer from poor reproducibility, such as low effective ternary device yields and a wide threshold voltage distribution, and improvements through organic material renovation are rather limited. In contrast, engineering of the electrode surfaces rather than molecule design has been demonstrated to boost the performance of organic electronics effectively. Herein, we introduce surface engineering into organic multilevel RRAMs to enhance their ternary memory performance. A new asymmetric conjugated molecule composed of phenothiazine and malononitrile with a side chain (PTZ-PTZO-CN) was fabricated in an indium tin oxide (ITO)/PTZ-PTZO-CN/Al sandwich-like memory device. Modification of the ITO substrate with a phosphonic acid (PA) prior to device fabrication increased the ternary device yield (the ratio of effective ternary device) and narrowed the threshold voltage distribution. The crystallinity analysis revealed that PTZ-PTZO-CN grown on untreated ITO crystallized into two phases. After the surface engineering of ITO, this crystalline ambiguity was eliminated and a sole crystal phase was obtained that was the same as in the powder state. The unified crystal structure and improved grain mosaicity resulted in a lower threshold voltage and, therefore, a higher ternary device yield. Our result demonstrated that PA modification also improved the memory performance of an asymmetric conjugated molecule with a side chain.

In order to methodically investigate the influence of sputtering power on interface states and performance of ITO/a-SiOx/n-Si device, the indium-tin oxide film (ITO) with thickness of 80 nm, was deposited on n-type silicon substrate by radio frequency magnetron sputtering. The device photovoltaic (PV) performance and the interface states of ITO/n-Si system were measured by solar simulator measurement system and the light-assisted high frequency capacitance-voltage (C–V) method, respectively. The experimental results demonstrate that the PV parameters of the ITO/a-SiOx/n-Si device achieve optimal values of PV parameters at 120 W (Voc~0.45 V, Jsc~28.57 mA/cm2, FF~71.20%, η~9.63%). Especially, the average interface state density (Dit) of ITO/n-Si interface drops from (1.29 ± 0.05) to (1.04 ± 0.02) × 1011 cm−2eV−1 when the sputtering power increases to 120 W, but the Dit sharply rises at higher sputtering power, which is negatively correlated with Voc and η. The effective minority carrier lifetime and O/Si ratio within interfacial layer were characterized by μ-PCD instrument and X-ray photoelectron spectroscopy, respectively. It is found that the device is well passivated by a-SiOx at 120 W. Moreover, the device performance is well-associated with the interface states and sputtering power.

One of the most pervasive environmental issues is water contaminated with oil or organic solvents; this global challenge calls for emerging materials that could effectively separate oil or organic solvents from water. Here, such a material is presented by integrating 3D porous graphene foam (GF) with a smart pH-responsive surface, showing switchable superoleophilic and superoleophobic properties in response to the medium pH. The key chemistry applied in this study is to modify the 3D porous GF with an amphiphilic copolymer containing a block of poly(2-vinylpyridine) and polyhexadecyl acrylate (P2VP-b-PHA), resulting in a smart GF (ss-GF) with an either superoleophilic or superoleophobic surface at different medium pH. The as-designed ss-GF can effectively absorb oil or organic solvents from the aqueous media by using its superoleophilic surface at pH of 7.0, and it can also completely release the adsorbates when the pH is switched to 3.0 (and the surface of ss-GF is therefore shifted to superoleophobic); with a continuous operation of many cycles (e.g., >10). Furthermore, the as-designed ss-GF shows superior absorption capacity for oil and organic solvent, with a high capacity of ≈196 times of the weight relative to that of the pristine ss-GF. The present work suggests encouraging applications of the ss-GF to water–oil and water–organic solvent separation.

A Gemini surfactant (N-dodecyl propylenediamine γ-diquaternium bromide) assisted hydrothermal route was presented for the facile synthesis of nanotile-like molybdenum disulfide/graphene (NTL-MoS2/G) hybrid. The effect of the Gemini surfactant on the microstructure and electrochemical lithium storage performance of the NTL-MoS2/G hybrid is investigated. It is found that MoS2 sheets in the hybrid display a nanotile-like morphology with 3–6 layers and are homogenously anchored on the surface of graphene. Due to their more edges, the nanotile-like MoS2 sheets facilitate lithium ion insertion/extraction and electrolyte access. The NTL-MoS2/G hybrid exhibits much higher reversible capacity with significantly enhanced cyclic stability and rate capability than the pristine MoS2. The improvement in electrochemical performances of the hybrid can also be contributed to the robust composite structure and synergistic effects between NTL-MoS2 and graphene sheets.

Few-layer molybdenum disulfide/graphene (FL-MoS 2 /GNS) composites are fabricated by a facile hydrothermal route and a post-annealing with the assistance of various cationic surfactants (dodecyltrimethylammonium bromide, DTAB; octyltrimethylammonium bromide, OTAB; and tetrabutylammonium bromide, TBAB), which have different alkyl-chain lengths and stereo configurations. The effects of these cationic surfactants on the microstructures and electrochemical performances of the FL-MoS 2 /GNS for lithium storage are investigated. It is demonstrated the cationic surfactants show some ability to control the microstructure (layer number) of FL-MoS 2 in composites. The electrochemical performances of FL-MoS 2 /GNS composites for lithium storage are greatly improved compared to the bare MoS 2 . Especially, FL-MoS 2 /GNS with ∼6 MoS 2 layers prepared with the assistance of OTAB exhibits very high reversible capacity of ∼1200 mAh g −1 with excellent cycle stability and enhanced rate capability. Electrochemical impedance spectrum also confirms that the FL-MoS 2 /GNS composite electrodes exhibit much lower electron-transfer resistance than the MoS 2 . The remarkable electrochemical performances of FL-MoS 2 /GNS composites can be attributed to the synergistic interaction between FL-MoS 2 and graphene and their quasi-3D architectures, which promote lithium diffusion, electron transfer and electrolyte access.

Photocatalysis by semiconducting materials loaded with non-metal or noble metals is an excellent strategy for removal of gaseous toluene. Herein, a new photocatalytic system was successfully prepared via simultaneously coupling atomic-scale Pt with MoS2 as co-catalysts to load on the surface of TiO2. The obtained photocatalysts exhibited good performance in toluene degradation by promoting the separation of photogenerated electron-hole pairs. The most efficient toluene degradation was achieved by the photocatalyst with a content of 2.0 wt% Pt-MT-1.0 (i.e., coupling 2.0 wt% atomic-scale Pt with 1.0 wt% MoS2), with a conversion ratio of 91.5%. This conversion ratio was higher than those of platinum-free MT-1.0 (33.9%) and pure TiO2 (72.3%). The results demonstrate the potential application of this new nanocomposite for efficient photocatalytic degradation of toluene.

ZIF-67-derived 3D hollow mesoporous crystalline Co3 O4 wrapped by 2D graphitic carbon nitride (g-C3 N4 ) nanosheets are prepared by low temperature annealing, and are used for the photocatalytic oxidation of nitric oxide (NO) at a concentration of 600 ppb. The p-n heterojunction between Co3 O4 and g-C3 N4 forms a spatial conductive network frame and results in a broad visible light response range. The hollow mesoporous structure of Co3 O4 contributes to the circulation and adsorption of NO, and the large specific surface area exposes abundant active sites for the reaction of active species. A maximum NO degradation efficiency of 57% is achieved by adjusting the mass of the Co3 O4 precursor. Cycling tests and X-ray diffraction indicate the high stability and recyclability of the composite, making it promising in environmental purification applications.

MnI2 is one of the important multiferroics materials with a layered, nearly two-dimensional (2D) structure due to van der Waals bonds. In this work, we developed physical vapor deposition and mechanical exfoliation methods to prepare 2D MnI2 flakes on amorphous SiO2 substrates. The morphologies, composition and structure properties of the 2D MnI2 flakes were characterized by optical microscopy, atomic force microscopy, scanning electronic microscope and Raman spectroscopy. Furthermore, we systematically studied the degradation of the MnI2 flakes. With h-BN and PMMA as protective materials, we improved the stability of the MnI2 flakes and slow down the degradation process under moisture conditions. In this regard, we provided MnI2 flakes as new 2D materials with effective protection, which may pave the way for the application of low dimensional multiferroics materials in the future.

A multi-functional core–shell nanocarrier was successfully prepared for near-infrared light- and pH-controlled drug release as well as magnetic resonance imaging (MRI) and fluorescence imaging. On the one hand, the hollow porous Fe3O4 (HPFe3O4, ∼20 nm) which could be etched under acidic conditions inside the cancer cells was prepared as the “core” to load anti-cancer drugs. On the other hand, the targeting NIR light-responsive copolymer (DDACMM-PEG-FA) was synthesized by polymerization of coumarin-containing monomer (DDACMM), poly(ethylene glycol) (PEG) methyl ether methacrylate and N-hydroxysuccinimide (NHS) and then modified by folic acid (FA). The core–shell nanocarriers (HPFe3O4@DDACMM-PEG-FA) were obtained by coating the amphiphilic copolymers onto the hollow porous “core”. Since the copolymer could be disrupted under the irradiation of NIR light laser (800 nm) via a two-photon absorption process, the pre-loaded drugs (∼65–80%) could be released from the nanocarriers. More importantly, the subacid environment in the tumour could further etch the boundary area of uncovered HPFe3O4, which further improved the efficiency of the drug release (about 20% increase in 24 h). The in vitro experiments indicated that the nanocarriers were biocompatible and could easily target the tumour cells that over-expressed folic acid receptor (FR(+)) and release the pre-loaded drugs successfully. In addition, because of the superparamagnetism of HPFe3O4 and the fluorescence of the polymer, the MRI and cell fluorescence imaging could be used to track the process of drug delivery.

We have developed an easy approach to obtain hydrophilic modified MSPNPs (M-MSPNPs) by simply coating monodispersed hydrophobic magnetite (Fe3O4) superparamagnetic nanoparticles (MSPNPs) with functional amphiphilic oligomers. The resulting M-MSPNPs have abundant chelation groups on their surfaces, which could bond with Hg2+and exhibit excellent ability in the fast, efficient and selective removal of Hg2+from water samples by low-field magnetic separation.

Aggregated or solid state red fluorescent materials with efficient light emission are rare but have wide applications in optoelectronic and biological fields. Herein, two pyran derivatives, EtAmPy and EtOxPy with different charge transfers (CT), were designed as initiators and introduced to polystyrene chains via atom transfer radical polymerization (ATRP). The emission of EtAmPy was quenched both in highly polar solvents and in an aggregated state because of its strong CT and intermolecular interactions, respectively. After EtAmPy was introduced to normal polystyrene chains, the obtained functional PS emitted strong red light with a quantum yield of 37% in an aggregated state. Differently from EtAmPy, EtOxPy, possessing a weak CT and not being sensitive to the change of microenvironment, was AIE-active and displayed a large red shift in emission spectra in an aggregated state. Meanwhile, the functional PS initiated by EtOxPy showed obviously blue-shifted emission, compared to its initiator, in an aggregated state by reducing their intermolecular interactions. EtAmPy-functionalized polystyrene showed a successful application in cell imaging. Therefore, using the CT effect in molecular design and polymerization is beneficial to obtaining new red emission probes.

A cationic surfactant-assisted hydrothermal route is developed for the facile synthesis of graphene-like MoS2/graphene (GL-MoS2/G) composites based on the hydrothermal reduction of Na2MoO4 and graphene oxide sheets with L-cysteine in the presence of cetyltrimethylammonium bromide (CTAB), following by annealling in N2 atmosphere. The GL-MoS2/G composites are characterized by X-ray diffraction, electron microscopy, high-resolution transmission electron microscopy, and Raman spectroscopy. The effects of CTAB concentration on the microstructures and electrochemical performances of the composites for reversible Li+ storage are investigated. It is found that the layer number of MoS2 sheets decreases with increasing CTAB concentration. The GL-MoS2 sheets in the composites are few-layer in the case of 0.01∼0.03 mol L−1 CTAB of hydrothermal solution and single-layer in the case of 0.05 mol L−1 CTAB. The GL-MoS2/G composites prepared with 0.01–0.02 mol·L−1 of CTAB solution exhibit a higher reversible capacity of 940–1020 mAh g−1, a greater cycle stability, and a higher rate capability than other samples. The exceptional electrochemical performance of GL-MoS2/G composites for reversible Li+ storage could be attributed to an effective integration of GL-MoS2 sheets and graphene that maximizes the synergistic interaction between them.

Multifunctional theranostic systems with good biocompatibility, strong clinical imaging capability, and target specificity are the desired features of future medicine. Here, the design of a theranostic nanocomposite capable of simultaneous targeting and imaging of the cancer cells is presented. It releases its drug payload by a controlled release mechanism. The nanocomposite contains luminescent gold nanocluster (L-AuNC) photostable and biocompatible diagnostic probes conjugated to a folic acid (FA)-modified pH-responsive amphiphilic polymeric system for controlled drug release. The nanocomposite uses a core-satellite structure to encapsulate hydrophobic drugs and releases the drug payload in mildly acidic endosomal/lysosomal compartments by the action of the pH-labile linkages in the polymer. In vivo studies show the selective accumulation of the FA-conjugated nanocomposite in tumor tissues by folate-receptor-mediated endocytosis. These findings demonstrate the potential of the nanocomposite as a nontoxic, folate-targeting, pH-responsive drug carrier that is useful for the early detection and therapy of folate-overexpressing cancerous cells.

The effect of rapid thermal annealing (RTA) on the compositional ratio of atoms and interfacial zone of Cu(In,Ga)Se 2 (CIGS) solar cells was systematically studied using X-ray photoelectron spectroscopy. The RTA treatment induced the diffusion of Al, Zn, and Se atoms, which increased the compositional ratio of these atoms in the corresponding layer. The ratio and characteristics of Cu/(In + Ga) and Ga/(In + Ga) were further modulated to attain higher efficiency in the devices. Furthermore, the width of the interfacial zone decreased at the Mo/CIGS interface because the diffusion depth of the Se atoms contracted from 1300 nm to 1200 nm. After RTA treatment, the absolute efficiency of the CIGS solar cells was enhanced by 1.2%. Our results suggest that RTA treatment reduces series resistance, optimizes the position of the minimum bandgap in the CIGS thin film, and improves the crystallinity of the CIGS thin film, which is responsible for the improvement in conversion efficiency.

A facile and scalable process was developed for the synthesis of single-layer MoS2–graphene nanosheet (SL-MoS2–GNS) composites based on the concurrent reduction of (NH4)2MoS4 and graphene oxide sheets by hydrazine in the presence of cetyltrimethylammonium bromide (CTAB), followed by annealing in a N2 atmosphere. The morphology and microstructure of the composites were examined by X-ray diffraction, field emission scanning electron microscopy, high-resolution transmission electron microscopy and Raman spectroscopy. The formation process for the SL-MoS2–GNS composites was also investigated. The SL-MoS2–GNS composites delivered a large reversible capacity and good cycle stability as a Li-ion battery anode. In particular, the composites easily surpassed MoS2 in terms of rate performance and cycle stability at high current densities. Electrochemical impedance spectroscopy revealed that the GNS in the composite not only reduced the contact resistance in the electrode but also significantly facilitated the electron transfer in lithiation and delithiation reactions. The good electrochemical performance of the composites for reversible Li+ storage could be attributed to the synergy between the functions of SL-MoS2 and GNS.

Mesoporous high-surface-area activated carbon (MHSA-AC), which has a honeycomb structure, was produced from coconut shells by simultaneous chemical and physical activation and used for the rapid adsorption of an anionic dye, namely acid orange 10 (AO10), from water. Owing to its porosity and high Brunauer–Emmett–Teller surface area (2283.91 m 2 g −1 ), MHSA-AC is a highly efficient adsorbent. It also has good biocompatibility and is a good immobilization carrier; the grooves on the MHSA-AC surface facilitate immobilization. Here, a new, highly efficient, and environmentally friendly simultaneous adsorption and biodegradation (SAB) process was developed. Highly concentrated AO10 (6000 mg L -1 , 20 mL) was removed with an efficiency of 100% (pH = 7, 35 °C) by SAB using cells immobilized on MHSA-AC (500 mg). The immobilized cells were used directly, without pretreatment; the SAB process is therefore simple and has good potential for application in the treatment of dyes in industrial wastewater.

Biotreatment of hexavalent chromium has attracted widespread interest due to its cost effective and environmental friendliness. However, the difficult separation of biomass from aqueous solution and the slow hexavalent chromium bioreduction rate are bottlenecks for biotechnology application. In this approach, a core-shell structured functional polymer coated magnetic nanocomposite was prepared for enriching the hexavalent chromium. Then the nanocomposite was connected to the bacteria via amines on bacterial (Bacillus subtilis ATCC-6633) surface. Under optimal conditions, a series of experiments were launched to degrade hexavalent chromium from the aqueous solution using the as-prepared bionanocomposite. Results showed that B. subtilis@Fe3O4@mSiO2@MANHE (BFSM) can degrade hexavalent chromium from the water more effectively (a respectable degradation efficiency of about 94%) when compared with pristine B. subtilis and Fe3O4@mSiO2@MANHE (FSM). Moreover, the BFSM could be separated from the wastewater by magnetic separation technology conveniently due to the Fe3O4 core of FSM. These results indicate that the application of BFSM is a promising strategy for effective treating wastewater containing hexavalent chromium.

Water pollution, a worldwide issue for the human society, has raised global concerns on environmental sustainability, calling for high-performance materials for effective treatments. Since the traditional techniques have inherent limitations in treatment speed and efficiency, nanotechnology is subsequently used as an environmental technology to remove pollutants through a rapid adsorption and degradation process. Therefore, here, various adsorbent and photodegradation composite materials leading to effective water remediation are summarized and predicted. Notably, recent advances in simultaneous adsorption and photodegradation micro-nanocomposites are outlined. Such materials can not only completely adsorb and remove contaminants, but the micro-nanocomposites can also be directly reused without further treatment. Finally, the future development of this unique system is discussed.

Graphene-encapsulated ordered aggregates of Fe3O4 nanoparticles with nearly spherical geometry and hollow interior were synthesized by a simple self-assembly process. The open interior structure adapts well to the volume change in repetitive Li+ insertion and extraction reactions; and the encapsulating graphene connects the Fe3O4 nanoparticles electrically. The structure and morphology of the graphene-Fe3O4 composite were confirmed by X-ray diffraction, scanning electron microscopy, and high-resolution transmission microscopy. The electrochemical performance of the composite for reversible Li+ storage was evaluated by cyclic voltammetry and constant current charging and discharging. The results showed a high and nearly unvarying specific capacity for 50 cycles. Furthermore, even after 90 cycles of charge and discharge at different current densities, about 92% of the initial capacity at 100 mA g–1 was still recoverable, indicating excellent cycle stability. The graphene-Fe3O4 composite is therefore a capab...

Nitrogen dioxide (NO2 ) emission has severe impact on human health and the ecological environment and effective monitoring of NO2 requires the detection limit (limit of detection) of several parts-per-billion (ppb). All organic semiconductor-based NO2 sensors fail to reach such a level. In this work, using an ion-in-conjugation inspired-polymer (poly(3,3'-diaminobenzidine-squarine, noted as PDBS) as the sensory material, NO2 can be detected as low as 1 ppb, which is the lowest among all reported organic NO2 sensors. In addition, the sensor has high sensitivity, good reversibility, and long-time stability with a period longer than 120 d. Theoretical calculations reveal that PDBS offers unreacted amine and zwitterionic groups, which can offer both the H-bonding and ion-dipole interaction to NO2 . The moderate binding energies (≈0.6 eV) offer high sensitivity, selectivity as well as good reversibility. The results demonstrate that the ion-in-conjugation can be employed to greatly improve sensitivity and selectivity in organic gas sensors by inducing both H-bonding and ion-dipole attraction.

A novel initiator containing proflavine derivative moiety, 3,6-dibromo-isobutyramide acridine (DIA), was synthesized and initiated the atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA). A water-soluble monomer, N,N-dimethylacrylamide (DMAA) was also initiated by DIA for comparison. The obtained fluorescent polymers, PMMA–DIA and PDMAA–DIA, were characterized by 1H NMR, GPC and TGA. The emission spectra of the fluorescent polymers exhibit obvious changes in color and fluorescence intensity along with pH varied in range of 3.0–9.0. In addition, the obtained polymers present good film-forming capacity and the films also have a high quantum yield and pH response. Both oil-soluble PMMA–DIA and water-soluble PDMAA–DIA have steady optical and chemical properties by containing proflavine moiety in the main chain.

Noble metals (Au, Pt, and Ru) loaded into carbon supports show excellent performance for CO oxidation. Herein, a tunable metal-organic framework (MOF) coating is applied to a macroscopic 3D Ru/graphene aerogel (Ru/GA) composite, using a facial step-by-step method. The open macroporous structure of the Ru/GA provides pathways for the access and diffusion of reactant and product molecules. The resulting HK (HKUST-1)-containing MOF composite exhibits good performance for CO adsorption. It can simultaneously adsorb and oxidize CO, which improves the reaction rate. In this work, the catalytic efficiency of the resulting catalyst is higher than that (≈48.4%) of the Ru/GA. These findings provide a simple method for increasing the instantaneous concentration of reactants around the catalyst, which in turn increases the reaction rate. The catalytic performances of composites subjected to different pretreatment conditions are also investigated. Hopefully, this finding may provide a feasible direction for the effective management of the diverse environment issues.

The practical application of organic memory devices requires low power consumption and reliable device quality. Herein, we report that inserting thienyl units into D-π-A molecules can improve these parameters by tuning the texture of the film. Theoretical calculations revealed that introducing thienyl π bridges increased the planarity of the molecular backbone and extended the D-A conjugation. Thus, molecules with more thienyl spacers showed improved stacking and orientation in the film state relative to the substrates. The corresponding sandwiched memory devices showed enhanced ternary memory behavior, with lower threshold voltages and better repeatability. The conductive switching and variation in the performance of the memory devices were interpreted by using an extended-charge-trapping mechanism. Our study suggests that judicious molecular engineering can facilitate control of the orientation of the crystallite in the solid state to achieve superior multilevel memory performance.

Water contamination becomes one of the most pervasive environmental issues all over the world in recent years. In this paper, the functionalization of graphene oxide (GO) with copolymers containing methacrylic acid (MAA) and butyl methacrylate (BMA) was investigated to prepare a new microcomposite material (PGO) via free radical solution polymerization. PGO was used for the adsorption of N,N-dimethylformamide (DMF) from aqueous solution by utilizing the characteristics of ultralarge surface and the Van der Waals force between DMF molecules and polymers on the surface of PGO. Besides, PGO was used not only a high-capable adsorbent but also a carrier for the immobilization of Paracoccus denitrificans cells in the treatment of high-concentrated DMF. Bacterial cells could immobilized on the PGO (PGO@P. denitrificans) stably by covalent coupling process after acclimatization and high-concentrated DMF (2000 mg/L) could be removed completely and relatively rapidly from aqueous solutions by the simultaneous adsorption-biodegradation (SAB) process of PGO@P. denitrificans. Furthermore, the excellent recycle performance of PGO@P. denitrificans made the whole process more economical and practical.

Crystalline hybrid microspheres, encapsulating a Au nanocore in the hollow cavity of a hairy semiconductor TiO2 shell (Au@air@TiO2-h microspheres) were prepared using template-assisted synthesis methods. The as-prepared microspheres are dispersed into a poly(3-hexylthiophene) (P3HT) matrix and used as a memory active layer. The electrical rewritable memory effects of Al/[Au@air@TiO2-h + P3HT]/ITO sandwich devices can be effectively and exactly controlled by tuning the microsphere content in the electroactive layer. To clarify the switching mechanism, different components in the device, such as P3HT and the microspheres, have been investigated. And it was determined that the switching mechanism can be attributed to the formation and rupture of oxygen vacancy filaments. These results suggest that the Au@air@TiO2-h microspheres are potentially capable of high density data storage. In addition, this finding could provide important guidelines for the reproducibility of nanocomposite-based memory devices and is helpful to demonstrate the switching mechanism of these devices.

Bacteria armed with thermally responsive silica nanoparticles are prepared for efficient biodegradation of phenol in water. The adsorption and release properties of thermally responsive silica nanoparticles under different temperatures can lead to a higher local concentration of phenol, which accelerates the biodegradation process.

Three O-fluoroazobenzene-based molecules were chosen as memory-active molecules: FAZO-1 with a D-A2-D symmetric structure, FAZO-2 with an A1-A2-A1 symmetric structure, and FAZO-3 with a D-A2-A1 asymmetric structure. Both FAZO-1 and FAZO-2 had a lower molecular polarity, whereas FAZO-3 had a higher polarity. The fabricated indium-tin oxide (ITO)/FAZO-1/Al (Au) and ITO/FAZO-2/Al (Au) memory devices both exhibited volatile static random access memory (SRAM) behavior, whereas the ITO/FAZO-3/Al (Au) device showed nonvolatile ternary write-once-read-many-times (WORM) behavior. It should be noted that the reproducibility of these devices was considerably high, which is significant for practical application in memory devices. In addition, the different memory performances of the three active materials were determined to be attributable to the stability of electric-field-induced charge-transfer complexes. Therefore, the switching memory behavior could be tuned by adjusting the molecular polarity.

The modification of the terminal electron-donating groups induces a critical change in molecular aggregation and the intermolecular charge-transfer effect of the symmetric D-A1-A2-A1-D molecules that correlate with an addressable variation of memory performance from binary to ternary.

Bacteria-mediated degradation of toxins has been reported as a practical technique for the innocuous removal of toxic organic compounds from water. Specifically, immobilized and pre-acclimatized Pseudomonas putida has been shown to clear low levels of contaminants (less than 2000 mg/L) from wastewater, wherein the bacteria consumes toxic aromatic compounds as the only source of carbon and energy. Here we report the preparation of a high-capacity composite adsorbent as an immobilization matrix for pre-acclimatized P. putida that is capable of complete degradation of 5000 mg/L of phenol within 80 hours. The composite adsorbent, a n-Butyl acrylate (BA)-resin evenly coated on polyester fiber (PF), can quickly reduce the phenol concentration to a level that is suitable for the immobilized bacteria to start the biodegradation process. Furthermore, the composite adsorbent (PF-BA) is regenerated during the biodegradation process without any additional manipulations, therefore it is reusable. As a whole, we provide a general strategy for more efficient biodegradation for phenol, which can be generalized to other water-soluble toxic organics removal for waste water treatment.

Recently, organic-inorganic hybrid perovskites (OIHP) are studied in memory devices, but ternary resistive memory with three states based on OIHP is not achieved yet. In this work, ternary resistive memory based on hybrid perovskite is achieved with a high device yield (75%), much higher than most organic ternary resistive memories. The pseudohalide-induced 2D (CH3 NH3 )2 PbI2 (SCN)2 perovskite thin film is prepared by using a one-step solution method and fabricated into Al/perovskite film/indium-tin oxide (glass substrate as well as flexible polyethylene terephthalate substrate) random resistive access memory (RRAM) devices. The three states have a conductivity ratio of 1:103 :107 , long retention over 10 000 s, and good endurance properties. The electrode area variation, impedance test, and current-voltage plotting show that the two resistance switches are attributable to the charge trap filling due to the effect of unscreened defect in 2D nanosheets and the formation of conductive filaments, respectively. This work paves way for stable perovskite multilevel RRAMs in ambient atmosphere.

Improving organic devices via molecular design is challenging and difficult to rationalize because individual molecular properties always convolute with intermolecular interaction and crystallinity to contribute the device performance. In this work, it is demonstrated for the first time that racemic effect can be utilized to effectively improve memory device performance. A pair of enantiomers and their mixture are used to prepare organic multilevel resistive random access memory (RRAM) devices. The RRAM devices fabricated from the equimolar mixture of enantiomers are of the lowest onset voltages and highest ternary device yield, independent of the preparation methods. Structural analysis of the powder, film, and single crystal of the equimolar mixture reveals formation of a real racemic compound, where π–π stacking in contrast to the only C–H–π interaction in the film of pure enantiomers appears. Since individual enantiomer has identical electronic properties, the discrepancy in device performance is attributed to the different intermolecular interactions.

Ternary resistive random access memory (RRAM) devices are fabricated from 1D d-π conjugated coordination polymer chains, which are synthesized via the coordination between Ni(II) salts and benzenetetramine or 3,3′,4,4′-biphenyltetramine in a solution process. The as-fabricated devices can retain their memory states for as long as three months at room temperature or work for at least 10 000 s at 150 °C, which is the highest working temperature reported for a ternary RRAM at the time of writing this paper. Thermogravimetric analysis indicates good thermal stability of these two materials because of their good crystallinity and strong intermolecular interaction. The long-term and high-temperature stability makes 1D conjugated coordination polymer chains a promising candidate for use as next-generation material for high-density data storage via RRAM techniques.

Hydrophilic molecularly imprinted microspheres (MIP@SiO2) for the adsorption of water-soluble molecules in real aqueous samples were successfully synthesized. In this strategy, a molecular imprinted polymer (MIP) was encapsulated in the hollow core of hollow mesoporous silica (HMS) particles via a 'ship-in-a-bottle' process. As the HMS shell contains plenty of Si-OH groups, the as-prepared microspheres proved to be hydrophilic and could be well dispersed in water. On the other hand, the MIP encapsulated in the HMS could specifically recognize small molecules with good binding efficiency through the mesoporous silica shell. Binding experiments in real aqueous solutions showed that the MIP@SiO2 composites have excellent recognition ability for specific molecules. Thus, MIP@SiO2 are highly promising alternatives to biological receptors with great potential for many analytical applications, such as environmental, food, and clinical analyses and other areas.

The light-triggered controlled release of anticancer drugs accompanied with NIR-responsive photodynamic therapy was prepared via a self-assembly process. Firstly, Mn(2+)-doped upconversion nanoparticles (UCNPs) were coated with a mesoporous silica shell and modified with photosensitizer (Chlorin e6) and long alkyl chains. And then the NIR light-responsive amphiphilic copolymer containing 9,10-dialkoxyanthracene groups was synthesized and then coated as the outermost layer. Upon irradiation with a 980 nm laser, the CCUCNPs@PM would absorb and then convert the NIR light to higher-energy visible red light (660 nm) via the UCNPs-based core, which could excite Chlorin e6 (Ce-6) to produce singlet oxygen ((1)O2). Then the (1)O2-sensitive dialkoxyanthracene group in the amphiphilic copolymer would be degraded and detach from the surface of the CCUCNPs@PM, followed by the controlled release of the pre-loaded drugs and the photodynamic therapy for cancer cells caused by the excess (1)O2. In vitro and in vivo experiments also demonstrated that the drug-loaded CCUCNPs@PM possessed better therapeutic efficacy compared with vacant ones. Therefore, the NIR light-controlled chemotherapy and photodynamic therapy could be realized simultaneously by CCUCNPs@PM.

Three small organic molecules that contained a phenothiazine backbone and triphenylamine (TPA), carbazole (CZ), or anthracene (AN) as a terminal electron donor were synthesized and fabricated in ITO/organic film/Al sandwiched memory devices. The influence of the extent of conjugation in the three molecules on the performance of their corresponding devices was investigated and the results showed that all of the fabricated devices exhibited nonvolatile ternary WORM character, whilst the switch threshold voltages decreased on moving from TPA to CZ and AN, which is promising for low-power-consumption data storage. These results revealed that tailoring the extent of conjugation in the terminal electron donor in the D-A molecules could effectively optimize the device performance, in particular the switch-threshold voltage, which could be instructive for the design of low-energy-consumption memory materials.

Virosecurinine is a major alkaloid of the plant Securinega suffruticosa and has been found to be a potent agent in inducing the differentiation of cancer cells. The present study aimed to investigate the antitumor effects of virosecurinine by inducing the apoptosis of leukemic K562 cells and to examine the underlying mechanisms. K562 cells were treated with different concentrations of virosecurinine (6.25, 12.5, 25, 50, 100 and 200 μmol/l) for 24, 48 and 72 h. The cell counting kit (CCK)-8 method was used to detect the antitumor effect of K562 cells in vitro. Flow cytometry was used to observe the apoptotic ratio and analyze the cell cycle following treatment with virosecurinine in K562 cells. Light and electron microscopy was used to identify morphological alterations in the virosecurinine-treated K562 cells. The mRNA levels of mammalian target of rapamycin (mTOR), SH2 domain-containing inositol-5′-phosphatase 2 (SHIP2), phosphatase and tensin homologue (PTEN) and breakpoint cluster region (BCR)/Abelson (ABL) were detected pre and post-virosecurinine treatment using reverse transcription quantitative polymerase chain reaction (RT-qPCR). The generation depression effects of K562 cells cultured in vitro were detected using CCK-8 technology, which revealed a dose and time-dependent association. The IC50 was 32.984 μmol/l at 48 h. Flow cytometric analysis indicated that treatment with virosecurinine at concentrations of 6.25, 25 and 50 μmol/l increased the apoptotic rate of the K562 cells and caused G1/S phase arrest. RT-qPCR indicated that virosecurinine upregulated the gene expression of PTEN and downregulated the expression of mTOR, SHIP-2 and BCR/ABL in K562 cells. Virosecurinine inhibited the growth and proliferation of the K562 cell lines and induced apoptosis in K562 cells by affecting the expression of mTOR, SHIP2, BCR/ABL and PTEN.

The Securinega alkaloids are a class of natural products isolated from plants of the Euphorbiaceae family. L-securinine induces apoptosis in the human promyelocytic leukemia cell line HL-60 indicating its potential as an efficient natural antitumor drug with low toxicity. The aim of the present study was to investigate the apoptotic effects of L-securinine on HL-60 cells and to explore its potential underlying molecular mechanism(s) as an antitumor agent. HL-60 cells were cultured with L-securinine. The proliferation and changes in cell morphology were evaluated by cell counting Kit-8 (CCK-8) assay and electron microscopy, respectively. Induction of apoptosis and cell cycle progression were investigated by flow cytometry. The PI3K/AKT/mTOR pathway gene expression was measured by quantitative PCR (qPCR). L-securinine decreased the viability of HL-60 cells in a dose- and time-dependent manner, with IC50 values at 24, 48 and 72 h post-treatment of 47.88, 23.85 and 18.87 µmol/l, respectively. Numerous apoptotic bodies were observed in the HL-60 cells treated with 25 µmol/l L-securinine for 48 h. L-securinine at 12.5, 25 and 50 µmol/l increased the rate of apoptosis in HL-60 cells, and G1/S phase progression was retarded. Furthermore, L-securinine induced downregulation of PI3K, AKT and mTOR gene expression and upregulation of PTEN gene expression in a dose-dependent manner. In conclusion, L-securinine induces apoptosis and inhibition of cell cycle progression in HL-60 cells by modulation of the PI3K/AKT/mTOR pathway gene expression. These observations indicate the potential of L-securinine as an antitumor agent.

Two-dimensional nanosheets can leverage on their open architecture to support facile insertion and removal of Li(+) as lithium-ion battery electrode materials. In this study, two two-dimensional nanosheets with complementary functions, namely nitrogen-doped graphene and few-layer WS2, were integrated via a facile surfactant-assisted synthesis under hydrothermal conditions. The layer structure and morphology of the composites were confirmed by X-ray diffraction, scanning electron microscopy and high-resolution transmission microscopy. The effects of surfactant amount on the WS2 layer number were investigated and the performance of the layered composites as high energy density lithium-ion battery anodes was evaluated. The composite formed with a surfactant : tungsten precursor ratio of 1 : 1 delivered the best cyclability (average of only 0.08% capacity fade per cycle for 100 cycles) and good rate performance (80% capacity retention with a 50-fold increase in current density from 100 mA g(-1) to 5000 mA g(-1)), and may find uses in power-oriented applications.