Search

Fatal pathogenic organisms have been detected by various point‐of‐care tests (PoCTs) in clinical samples. PoCTs based on portable electrical devices are able to detect organisms in simple and rapid method. Although electrical PoCT devices show ultra sensitivity when detecting pathogens in standard samples, their industrialization has been limited due to low reproducibility, sensitivity, and specificity, resulting from nonspecific binding issues by media. In this research, a perpendicular N‐heterocyclic carbene self‐assembled monolayer (NHC‐SAM) conjugated on graphene micropattern field‐effect transistors (NGMFETs) is first demonstrated for monitoring pathogens. Two single bonds of NHCSAM on GM are investigated via density functional theory (DFT) and surface analyses. Bioreceptors are conjugated on the side gate‐modulated NGMFET for ultra‐stable on‐site detection. The side‐gated BNGMFETs system displayed remarkable performance in the detection of the following: i) SARS‐CoV‐2 spike protein S1 (limit of detection (LOD): ≈10 pg mL−1) in CTM, ii) O. tsutsugamushi Ab (LOD: ≈1 pg mL−1), and iii) E. coli (LOD: 10° CFU mL−1) in serum. Compared to commercial methodology, the platform presents 102 times higher LODs towards those pathogens in clinical samples with higher reproducibility. Based on these results, side‐gated BNGMFETs can be utilized as universal PoCT during pandemics. [ABSTRACT FROM AUTHOR]

Conducting polymers (CPs) are an innovative class of materials recognized for their high flexibility and biocompatibility, making them an ideal choice for health monitoring applications that require flexibility. They are active in their design. Advances in fabrication technology allow the incorporation of CPs at various levels, by combining diverse CPs monomers with metal particles, 2D materials, carbon nanomaterials, and copolymers through the process of polymerization and mixing. This method produces materials with unique physicochemical properties and is highly customizable. In particular, the development of CPs with expanded surface area and high conductivity has significantly improved the performance of the sensors, providing high sensitivity and flexibility and expanding the range of available options. However, due to the morphological diversity of new materials and thus the variety of characteristics that can be synthesized by combining CPs and other types of functionalities, choosing the right combination for a sensor application is difficult but becomes important. This review focuses on classifying the role of CP and highlights recent advances in sensor design, especially in the field of healthcare monitoring. It also synthesizes the sensing mechanisms and evaluates the performance of CPs on electrochemical surfaces and in the sensor design. Furthermore, the applications that can be revolutionized by CPs will be discussed in detail. [ABSTRACT FROM AUTHOR]

In this study, a straightforward, eco-friendly strategy for the phase modulation of MoS2 in 2D materials was developed for green-solvent-phase co-exfoliation and subsequent solvent-free drying/annealing processes, yielding binary-metal oxide nanoparticulate-decorated heterolayered 2D nanohybrids. As a green solvent, ethanol with poly(N-vinyl-2-pyrrolidone) provided an effective surface tension for liquid-phase exfoliation of the 2D materials (MoS2 and graphene). Electron injection of binary metal oxides (NiFe2O4) and graphene functional groups to the Mo 4d orbital played an important role in the modulating phase conversion of semiconductive MoS2 to metallic MoS2 in the nanohybrids. Moreover, the introduction of MoS2 and graphene tuned the diameter (∼6 nm) and effective crystalline domains of the NiFe2O4 nanoparticles in the resulting nanohybrid. The electrocatalytic activity of the nanohybrids exhibited outstanding performance in the hydrogen and oxygen evolution reactions due to the synergetic effects of the modified MoS2/graphene/NiFe2O4 components. Density functional theory calculations and the Tafel slope indicated that the combination of 1T-MoS2/graphene/NiFe2O4 nanohybrids achieved a lower activation barrier at the first hydrogen absorption step and the RDS for the interaction of adsorbed oxygen atoms with hydroxide in the hydrogen and oxygen evolution reactions. The nanohybrids were prepared as symmetric electrodes to assemble an environmentally-benign hydrogel cell for water-splitting systems, exhibiting excellent stability in deswelling–swelling cycles. We believe that the proposed process allows for phase-modulating 2D materials while alleviating the negative impact on the environment, creating desirable functionality for various catalytic applications. [ABSTRACT FROM AUTHOR]

Discarded or waste plastic in the environment can alter the health of habitats and natural processes, severely impacting ecosystems, food production capabilities, people's livelihoods, and social well-being. Plastics constitute a major material group with a global production of approximately 368 million metric tons per year. Among them, polyurethane (PU) is a flexible substance with a wide range of applications in daily life and offers adaptability, toughness, and affordability resulting in a rapidly increasing demand worldwide. In contrast, recycling of PU is still limited, and more research and development are needed to improve the efficiency and effectiveness of PU recycling and upcycling. Herein, we demonstrated a sustainable and eco-friendly conversion of waste PU into useful active micro-cleaners via a deep eutectic solvent (DES) assisted solvothermal process. In this process, a greener solvent system containing choline chloride and ferric chloride which acts as a solvent and catalyses PU foam to form valuable carbonaceous products under solvothermal conditions was established. The prepared PU-derived carbon (PUC) was characterized using suitable analytical techniques to understand its physicochemical properties and used for the adsorption of a variety of contaminants such as malachite green, methylene blue, and a pharmaceutical ciprofloxacin molecule. Furthermore, PUC successfully acted as a Fenton-like catalyst and exhibited an excellent recyclability efficiency (>80%) even after the 5th cycle which shows the potential of the material in sustainable wastewater treatment. [ABSTRACT FROM AUTHOR]

Nanocrystals of Cs3Cu2I5, a metal halide with promising potential as a perovskite substitute, are successfully grown on graphene nanosheets. An intermediate stage of physically exfoliated graphene nanosheets, concurrent with the formation of copper‐based seeds on graphene surface, is developed, for the first time, allowing for the subsequent growth of Cs3Cu2I5 nanocrystals (CsNCs) to obtain CsNCs‐decorated graphene nanohybrids (CsGNHs). The morphology and properties of the CsGNHs depend on the input amount of graphene nanosheets during the reaction. The photoluminescence intensity of the CsGNHs decreases with increasing graphene content, indicating that graphene facilitates nonradiative energy transfer from the CsNCs in the CsGNHs. The inherent self‐trapping exciton emission of the CsNCs is also affected by the graphene substrate. As the graphene content increases, the emission peaks of the CsGNHs broaden and diminish. The CsGNHs emit a stable solid‐state luminescence with a large Stokes shift (zero self‐absorption) under a high‐energy ultraviolet (UV) light. Consequently, the CsGNHs can act as optoelectronic transducers and selectively generate a turn‐on photocurrent response under specific‐wavelength UV light. Additionally, a new anticounterfeiting strategy is developed using the CsGNHs as a luminescent black ink to fabricate luminescent quick‐response codes with fake pixels. [ABSTRACT FROM AUTHOR]

Isothiazolinones, which are widely used as chemical additives in many industries, may lead to skin irritation and allergies, thereby adversely influencing human health and the environment. Therefore, this paper proposes an efficient strategy for screening nanohybrid transducers to selectively detect 2-octyl-3-isothiazolinone (OIT) as a representative isothiazolinone. Chemical receptor (CR) candidates consisting of two parts: a reactive imidazole unit and side functional group for covalent conjugation with graphene and noncovalent interaction with the target, respectively, were designed. Five CR structures were selected and synthesized based on density-functional-theory calculations. The synthesized CRs were anchored to graphene for electrochemical transduction. The alkyl groups calculated to have the highest chemical affinities toward OIT were introduced in the CR/graphene nanohybrids (CGNHs). The electrochemical responses of the CGNHs toward OIT depended on the CR type, OIT concentration, and applied potential. Therefore, the combination of five CGNHs as a transducer with different potentials enabled the facile and effective detection of OIT (1–200 mg L–1) from the interferences through principal component analyses. The best CR corresponded to the dodecyloxy group, and the optimal measurement conditions included a scan rate of 25 mV s–1 and applied potentials of −0.75, 0.08, and 1.30 V (vs Ag/AgNO3). The proposed strategy can facilitate the efficient development of nanotransducers for identifying different types of chemical species such as biocides. [ABSTRACT FROM AUTHOR]

To build devices offering users comfortable experience, it is important to focus on form factor and multifunctionality. In this study, for the first time, multifunctional Zn clusters with shape memory, self‐healing, triboelectricity, and optical sensing synergized with rollable form factor are designed and fabricated by coordinating COO− and Zn2+. As pore forming agent, Zn clusters produce hierarchical porous structure depending on Zn amount. Zn clusters are applied as message transmitters and charge containers in optical sensing and corona charge injection, respectively. Moreover, Zn clusters in PVB‐COO‐Zn serve as positive tribomaterial due to Zn ion doping effect, increasing the output performance as the Zn amount reaches 20 wt%. In addition, injecting positive charge into PVB‐COO‐Zn 20 lead to more than 24 times increase in output performance compared to those of non‐porous structures. The reversibility of Zn clusters endows shape memory and self‐healing, synergized with the rollable form factor. The rollability is implemented using the long alkyl chain and the energy absorption of porous structure, providing damage resistance. The advancements in this work provide opportunities for multifunctional and unique applications (shape memory rotating‐triboelectric nanogenerator, rollable self‐healing touchpad, hidden tag) synergized with rollability that accomplishes working in broadened condition in near future. [ABSTRACT FROM AUTHOR]

Recent interest in research on photoluminescent molecules due to their unique properties has played an important role in advancing the bioimaging field. In particular, small molecules and organic dots as probes have great potential for the achievement of bioimaging because of their desirable properties. In this review, we provide an introduction of probes consisting of fluorescent small molecules and polymers that emit light across the ultraviolet and near-infrared wavelength ranges, along with a brief summary of the most recent techniques for bioimaging. Since photoluminescence probes emitting light in different ranges have different goals and targets, their respective strategies also differ. Diverse and novel strategies using photoluminescence probes against targets have gradually been introduced in the related literature. Among recent papers (published within the last 5 years) on the topic, we here concentrate on the photophysical properties and strategies for the design of molecular probes, with key examples of in vivo photoluminescence research for practical applications. More in-depth studies on these probes will provide key insights into how to control the molecular structure and size/shape of organic probes for expanded bioimaging research and applications. [ABSTRACT FROM AUTHOR]

In this study, we demonstrated a strategy for fabricating unique 2D ternary nanohybrids comprising N-doped graphene (NG) and in-plane WSe2–WO3 (W–W) heterojunction nanosheets (NG/W–Ws) through heat treatment/oxidation processes using a graphene/PANI/WSe2 precursor. PANI served as an exfoliating and N-doping agent and played a crucial role along with graphene in developing a high effective surface area and pore volume. The NG/W–Ws showed a single kinetic reaction (the Volmer–Heyrovsky step) with a single onset potential for the hydrogen evolution reaction (HER) and decreased overpotentials; this was attributed to the intercalated NG. Density functional theory calculations indicated that NG decreases the energy gap between the LUMO and HOMO levels, and the differential Gibbs free energy of atomic hydrogen on the catalyst surface was close to zero. Therefore, the NG/W–Ws presented a linear relationship between their electrocatalytic performance (e.g., onset potential and overpotential) and mass loading (thickness). The total resistance and capacitance of the NG/W–Ws decreased and increased, respectively, with increasing electrode thickness, highlighting the synergy between the NG and W–W components. We believe that the proposed strategy will ensure the facile fabrication of multicomponent 2D heterostructured nanohybrids for high mass-loading electrocatalyst systems and will contribute to the practical commercialization of 2D nanohybrids as electrocatalysts. [ABSTRACT FROM AUTHOR]

Research effort has increasingly been devoted to exploiting efficient noble-metal-free electrocatalysts because of their low cost and abundancy. Herein, metallic nanoparticulate-containing carbon nanofibers (MCNFs) featuring interior, nanoparticulate-in-pore structures were fabricated by taking advantage of cationic metal species/anionic surfactant complexes (MSCs). Binary MSC mixtures containing Fe–Co, Fe–Ni, and Co–Ni species were used to control not only the size/loading amount of the metallic phases but also the microstructural characteristics of the nanofiber matrices. Compared to their single MSC counterparts, the binary MSC mixtures allowed the generation of unique metallic phases, such as binary transition-metal oxides, and resulted in enhanced surface area/porosity and reduced charge transfer resistance. The noble-metal-free MCNFs were demonstrated as electrocatalysts for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). The MCNFs prepared using binary combinations of Fe–Ni and Co–Ni, viz., FeNiCNFs and CoNiCNFs, showed outstanding performances for the OER and HER, respectively. For the OER particularly, at potentials exceeding 1.6 V (vs RHE), the FeNiCNFs showed higher current densities than that of the well-known, conventionally used electrocatalyst RuO2. For overall water splitting, an asymmetric FeNiCNF∥CoNiCNF cell rendered performance stability that was 15% better than that of the RuO2∥Pt/C control cell. Based on the results of this study, various combinations of MSCs with controlled loading into functional matrices can be prepared to yield efficient, cost-effective electrocatalysts for water splitting. [ABSTRACT FROM AUTHOR]

Improvements in Fenton reagents and processing systems are greatly desired. Here, we report the preparation of bifunctional iron/carbon nanofibers (ICNFs) with tailored microstructural characteristics for use as heterogeneous Fenton catalysts; these were constructed using binary/ternary polymer blends (polyacrylonitrile together with either/both poly-(methyl methacrylate) or/and poly-(N-vinyl-2-pyrrolidone)) and iron-(II) acetate as carbon and transition-metal precursors, respectively. The microphase separation of the different polymers containing the iron precursor was employed to control the (i) textural and electrical properties of the resulting carbon nanofibers and (ii) size and spatial distribution of the formed iron phases. Promising ICNFs with large effective surface areas and high porosities were successfully produced. Since the ICNF Fenton catalysts are also electrically conductive, a flow-controllable system with an integrated electrochemical three-electrode setup was also built, in which the ICNFs were employed as the sensing electrode for the electrochemical detection of dye influx. Amperometric monitoring of the flow system allowed the rapid detection of the dye influx introduced into the system, and then the Fenton reaction, coupled with a cathodic electrodeposition process, proceeded to degrade the dye. Further optimization of such systems employing ICNFs as the sensing electrode and Fenton catalyst will likely lead to cost-effective, energy-efficient water treatment processes. [ABSTRACT FROM AUTHOR]

Rational design of the micro-nanomorphology is highly desired for metal hydroxides to achieve overall high-performance electrodes for supercapacitor and energy storage applications. Here, in the current study, we have succeeded in controlling the morphology of Sn/Co nanolayered structures to obtain plate and nanofibrous morphologies. Additionally, the plate nanostructures could be transformed to obtain plate-nanofibrous morphologies. In this trend, dual anions such as cyanate and nitrate are applied to intercalate among the nanolayers of cobalt-tin and act as building blocks or pillars, producing a series of nanolayered structures. By repulsion forces among the intercalated anions, the nanolayers of Sn/Co are curled and converted to nanofibers. This conversion was confirmed by scanning electron microscopy. In addition, the intercalation reactions and nanolayered structures were indicated by X-ray diffraction, thermal analyses and Fourier-transform infrared spectroscopy. The electrochemical supercapacitive behavior of the different nanostructures of Sn/Co HDS and Sn/Co LDH, such as plate, Plate-nanofiber and nanofibrous morphology has been investigated in three assembly electrode system. The results suggested that the nanofiber morphology of Sn/Co LDH exhibited better specific capacitance performance than the other two morphologies. The enhanced specific capacitance (658 Fg−1) and excellent cyclic stability (89%) of the nanofibers of the Sn/Co LDH could be attributed to the synergistic effects between the electric double layer capacitive character of the tin and the pseudocapacitance nature of the cobalt. [ABSTRACT FROM AUTHOR]

The fascinating properties of single‐layer graphene isolated by mechanical exfoliation have inspired extensive research efforts toward two‐dimensional (2D) materials. Layered compounds serve as precursors for atomically thin 2D materials (briefly, 2D nanomaterials) owing to their strong intraplane chemical bonding but weak interplane van der Waals interactions. There are newly emerging 2D materials beyond graphene, and it is becoming increasingly important to develop cost‐effective, scalable methods for producing 2D nanomaterials with controlled microstructures and properties. The variety of developed synthetic techniques can be categorized into two classes: bottom‐up and top‐down approaches. Of top‐down approaches, the exfoliation of bulk 2D materials into single or few layers is the most common. This review highlights chemical and physical exfoliation methods that allow for the production of 2D nanomaterials in large quantities. In addition, remarkable examples of utilizing exfoliated 2D nanomaterials in energy and environmental applications are introduced. [ABSTRACT FROM AUTHOR]

Combining the characteristics of different materials offers exciting new opportunities for advanced applications in various fields. Herein, white light‐emitting diodes (WLEDs) with >200% reversible stretchability are fabricated using six‐color quantum dots (QDs) gel emitters. Stable aqueous‐phase alloy core/shell QDs with high quantum yield are obtained via ligand exchange using a ternary solvent system. Transparent and highly stretchable gels with large pores are created by binary‐solvent‐based gelation at low temperatures. Importantly, the QDs and the gel originate from the same two solvents, which make the QDs highly compatible with the gelation process. Consequently, QDs of six different colors are incorporated into the gel without any property degradation. The excellent optical properties of the QDs in the liquid phase (e.g., 17% higher photoluminescence (PL) intensity) are retained in the gel phase. The QD gel (QDG) exhibits elastic deformation up to 200%, with uniform PL over the entire gel. A down‐conversion WLED built using the QDG emitter produces cool white light with a color temperature of 6100 K, a color rendering index of 94, and a luminous efficacy of 72 lm W−1. In addition, the performance of the QDG‐based WLED remains unchanged even after more than 1000 bending/stretching cycles. [ABSTRACT FROM AUTHOR]

Insulating polymers have received little attention in electronic applications. Here, we synthesize a photoresponsive, amphiphilic block copolymer (PEO-b-PVBO) and further control the chain growth of the block segment (PVBO) to obtain different degrees of polymerization (DPs). The benzylidene oxazolone moiety in PEO-b-PVBO facilitated chain-conformational changes due to photoisomerization under visible/ultraviolet (UV) light illumination. Intercalation of the photoresponsive but electrically insulating PEO-b-PVBO into graphene sheets enabled electrical monitoring of the conformational change of the block copolymer at the molecular level. The current change at the microampere level was proportional to the DP of PVBO, demonstrating that the PEO-b-PVBO-intercalated graphene nanohybrid (PGNH) can be used in UV sensors. Additionally, discrete signals at the nanoampere level were separated from the first derivative of the time-dependent current using the fast Fourier transform (FFT). Analysis of the harmonic frequencies using the FFT revealed that the PGNH afforded sawtooth-type current flow mediated by Coulomb blockade oscillation. Block copolymers are electrically insulating and therefore characterization with electrical or electrochemical methods is not possible. Here, the authors demonstrate electrical monitoring of the photoisomerization transition in a benzylidene oxazolone block co-polymer intercalated into graphene sheets. [ABSTRACT FROM AUTHOR]

Insulating polymers have received little attention in electronic applications. Here, we synthesize a photoresponsive, amphiphilic block copolymer (PEO-b-PVBO) and further control the chain growth of the block segment (PVBO) to obtain different degrees of polymerization (DPs). The benzylidene oxazolone moiety in PEO-b-PVBO facilitated chain-conformational changes due to photoisomerization under visible/ultraviolet (UV) light illumination. Intercalation of the photoresponsive but electrically insulating PEO-b-PVBO into graphene sheets enabled electrical monitoring of the conformational change of the block copolymer at the molecular level. The current change at the microampere level was proportional to the DP of PVBO, demonstrating that the PEO-b-PVBO-intercalated graphene nanohybrid (PGNH) can be used in UV sensors. Additionally, discrete signals at the nanoampere level were separated from the first derivative of the time-dependent current using the fast Fourier transform (FFT). Analysis of the harmonic frequencies using the FFT revealed that the PGNH afforded sawtooth-type current flow mediated by Coulomb blockade oscillation. Block copolymers are electrically insulating and therefore characterization with electrical or electrochemical methods is not possible. Here, the authors demonstrate electrical monitoring of the photoisomerization transition in a benzylidene oxazolone block co-polymer intercalated into graphene sheets. [ABSTRACT FROM AUTHOR]

More specifically, we examine the development of new nanomedicines in combination therapy for cancer treatment, the use of thermosensitive liquid suppositories for drug delivery, and the development of nanoparticulate photoluminescent probes for bioimaging. The study report provided a comprehensive characterization of the suppository (including its stability, drug release profile, and cytotoxicity) and demonstrated its potential as a new drug delivery system for metoprolol. Polymer nanomaterials have emerged as a promising class of materials within the field of biomedicine, owing to their unique physical, chemical, and biological properties. [Extracted from the article]

Vertically random-layered three-dimensional ternary nanohybrids were synthesized by combining graphene, molybdenum disulfide (MoS2), and polyaniline (PANI) via a simple physical exfoliation process. During this process, PANI penetrates the interlayers of bulk MoS2 without the requirement for any additional chemical treatment, effectively dispersing MoS2 layers in the liquid phase. In addition, graphene, with several functional groups on its surface, and PANI convert the semiconducting trigonal prismatic phase of MoS2 to a metallic octahedrally coordinated phase, thereby enhancing the electrical conductivity. Moreover, the obtained nanohybrid has an open porous structure that facilitates electrolyte-mediated ion and charge transfer, which increases the effective surface area for electrochemical reactions and charge storage. The effect of different graphene, MoS2, and PANI contents on the electrical/electrochemical properties of the nanohybrids was investigated, and the optimal composition for the use of the nanohybrid as an electrode material was determined. Notably, the nanohybrid with a nominal graphene/MoS2/PANI weight ratio of 1 : 1 : 80 exhibited excellent electrochemical properties, exemplified by the prominent redox reaction, low charge transfer resistance, and high specific capacitance. Flexible all-solid-state capacitor cells employing the nanohybrid achieved a maximum capacitance of 162 F g−1, good flexibility, and good long-term cycling stability in two different electrolytes, i.e., acidic and neutral solution. [ABSTRACT FROM AUTHOR]

Hybrid organic–inorganic nanocomposites have attracted considerable attention because they have the advantages of both conjugated polymers (CPs) and nanocrystals (NCs). Recent developments in the interfacial engineering of CP–NC organic–inorganic nanocomposites enabled the formation of an intimate contact between NCs and CPs, facilitating electronic interactions between these two constituents. To design CP–NC nanocomposites, several approaches have been introduced, including ligand refluxing, direct grafting methods, direct growth of NCs in proximity to CPs, and template-guided strategies. In this review, the general reactions of ligand exchange processes, purification methods, and characterization techniques have been briefly introduced. This is followed by a highlight of recent advances in the synthesis of hybrid CP–NC nanocomposites and newly developed inorganic surface treatments, as well as their applications. An outlook for future directions in this area is also presented. [ABSTRACT FROM AUTHOR]

The hybridization of an electrochemically active metal oxide with electrically conductive carbon nanofibers (CNFs) has been utilized as a solution to overcome the energy density limitation of carbon-based supercapacitors as well as the poor cyclic stability of metal oxides. Herein, we have demonstrated the growth of binary metal oxide nanosheets on the engineered surface of CNFs to fully exploit their electrochemical activity. Metal oxide nanosheets were observed to grow vertically from the surface of CNFs. The high structural toughness of the CNF–metal oxide composite under strong sonication indicated strong interfacial binding strength between the metal oxide and the CNFs. The rationally designed porous CNFs presented a high specific surface area and showed high capacity for adsorbing metal ions, where the active edge sites acted as anchoring sites for the nucleation of metal oxides, thereby leading to the formation of a well dispersed and thin layer structure of binary metal oxide nanosheets. Excellent electrochemical performance (e.g., specific capacitance of 2894.70 F g−1 and energy density of 403.28 W h kg−1) was observed for these binary metal oxide nanosheets, which can be attributed to the large increase in the accessible surface area of the electrochemically active metal oxide nanosheets due to their homogeneous distribution on porous CNFs, as well as the efficient charge transfer from the metal oxide to the CNFs facilitated the improvement in the performance. [ABSTRACT FROM AUTHOR]

Graphene/polyaniline multilayered nanostructures (GPMNs) are prepared using a straightforward process through which graphite is physically exfoliated with quaternary polyaniline (PANI)-glue. This is only accomplished by sonication of the graphite flakes in an organic solvent to form continuous films with PANI. During the sonication, the conductive PANI-glue is spontaneously intercalated between the graphene sheet layers without deterioration of the sp2 hybridized bonding structure. The resultant free-standing, flexible films are composed of a network of overlapping graphene sheets and are shown to have a long-range structure. The effects of different PANI content ratios and different interfacial energies (depending on the dispersion solvent) on the morphology and properties of the resulting GPMN are examined. It is found that GPMNs dispersed in water have a maximum specific capacitance of 390 F g−1 in a three-electrode configuration. Importantly, the unique structural design of GPMNs enables their use as electrode materials for the fabrication of flexible, solid-state electrochemical capacitors, which show an enhanced performance compared to graphene-only devices. They exhibit a high specific capacitance of 200 F g−1, a cycling stability with capacitance retention of 82% after 5000 charge/discharge cycles, and, moreover, superior flexibility. [ABSTRACT FROM AUTHOR]

Cellulose, a natural polymeric material, has widespread technical applications because of its inherent structural rigidity and high surface area. As a conjugated polymer, polypyrrole shows practical potential for a diverse and promising range of future technologies. Here, we demonstrate a strategy for the real-time detection and removal of metal ions with polypyrrole/cellulose (PPCL) composite papers in solution. Simply, the conjugated polymer papers had different chemical/physical properties by applying different potentials to them, which resulted in differentiable response patterns and adsorption efficiencies for individual metal ions. First, large-area PPCL papers with a diameter of 5 cm were readily obtained via vapor deposition polymerization. The papers exhibited both mechanical flexibility and robustness, in which polypyrrole retained its redox property perfectly. The ability of the PPCL papers to recognize metal ions was examined in static and flow cells, in which real-time current change was monitored at five different applied potentials (+1, +0.5, 0, −0.5, and −1 V vs. Ag/AgCl). Distinguishable signals in the PPCL paper responses were observed for individual metal ions through principal component analysis. Particularly, the PPCL papers yielded unique signatures for three metal ions, Hg(ii), Ag(i), and Cr(iii), even in a real sample, groundwater. The sorption of metal ions by PPCL papers was examined in the flow system. The PPCL papers had a greatly superior adsorption efficiency for Hg(ii) compared to that of the other metal ions. With the strong demand for the development of inexpensive, flexible, light-weight, and environmentally friendly devices, the fascinating characteristics of these PPCL papers are likely to provide good opportunities for low-cost paper-based flexible or wearable devices. [ABSTRACT FROM AUTHOR]

Carboxylated polypyrrole (CPPy) nanotubes were fabricated by the chemical copolymerization of pyrrole and pyrrole-3-carboxylic acid (P3CA) using cylindrical micelle templates. Importantly, the chemical functionality of CPPy nanotubes was determined by the input amount of P3CA and their redox property was also retained without degradation. A field-effect-transistor (FET) sensor platform was constructed using liquid-ion gating. CPPy nanotubes were anchored on an amine-functionalized Au interdigitated microelectrode substrate to achieve high quality contact at the polymer/metal interface. Subsequently, heparin was covalently conjugated with the CPPy nanotubes via a diamino linker. The FET sensor based on heparin-conjugated CPPy nanotubes showed specific and fast response upon exposure to thrombin protein. [ABSTRACT FROM AUTHOR]

Perovskite solar cells are a hot topic of photovoltaic research, reaching, in few years, an impressive efficiency (25.5%), but their long-term stability still needs to be addressed for industrial production. One of the most sizeable reasons for instability is the doping of the Hole Transporting Material (HTM), being the salt commonly employed as a vector bringing moisture in contact with perovskite film and destroying it. With this respect, the research focused on new and stable "dopant-free" HTMs, which are inherently conductive, being able to effectively work without any addition of dopants. Notwithstanding, they show impressive efficiency and stability results. The dopant-free polymers, often made of alternated donor and acceptor cores, have properties, namely the filming ability, the molecular weight tunability, the stacking and packing peculiarities, and high hole mobility in absence of any dopant, that make them very attractive and a real innovation in the field. In this review, we tried our best to collect all the dopant-free polymeric HTMs known so far in the perovskite solar cells field, providing a brief historical introduction, followed by the classification and analysis of the polymeric structures, based on their building blocks, trying to find structure–activity relationships whenever possible. The research is still increasing and a very simple polymer (PFDT–2F–COOH) approaches PCE = 22% while some more complex ones overcome 22%, up to 22.41% (PPY2). [ABSTRACT FROM AUTHOR]

Lithium-ion batteries are today among the most efficient devices for electrochemical energy storage. However, an improvement of their performance is required to address the challenges of modern grid management, portable technology, and electric mobility. One of the most important limitations to solve is the slow kinetics of redox reactions associated to inorganic cathodic materials, directly impacting on the charging time and the power characteristics of the cells. In sharp contrast, redox polymers such as poly(2,2,6,6-tetramethyl-1-piperidinyloxy methacrylate) (PTMA) exhibit fast redox reaction kinetics and pseudocapacitors characteristics. In this contribution, we have hybridized high energy Li(NixMnyCoz)O2 mixed oxides (NMC) with PTMA. In this hybrid cathode configuration, the higher voltage NMC (ca. 3.7 V vs. Li/Li+) is able to transfer its energy to the lower voltage PTMA (3.6 V vs. Li/Li+) improving the discharge power performances and allowing high power cathodes to be obtained. However, the NMC-PTMA hybrid cathodes show an important capacity fading. Our investigations indicate the presence of an interface degradation reaction between NMC and PTMA transforming NMC into an electrochemically dead material. Moreover, the aqueous process used here to prepare the cathode is also shown to enable the degradation of NMC. Indeed, once NMC is immersed in water, alkaline surface species dissolve, increasing the pH of the slurry, and corroding the aluminum current collector. Additionally, the NMC surface is altered due to delithiation which enables the interface degradation reaction to take place. This reaction by surface passivation of NMC particles did not succeed in preventing the interfacial degradation. Degradation was, however, notably decreased when Li(Ni0.8Mn0.1Co0.1)O2 NMC was used and even further when alumina-coated Li(Ni0.8Mn0.1Co0.1)O2 NMC was considered. For the latter at a 20C discharge rate, the hybrids presented higher power performances compared to the single constituents, clearly emphasizing the benefits of the hybrid cathode concept. [ABSTRACT FROM AUTHOR]

Currently, polymers are competing with metals and ceramics to realize various material characteristics, including mechanical and electrical properties. However, most polymers consist of organic matter, making them vulnerable to flames and high-temperature conditions. In addition, the combustion of polymers consisting of different types of organic matter results in various gaseous hazards. Therefore, to minimize the fire damage, there has been a significant demand for developing polymers that are fire resistant or flame retardant. From this viewpoint, it is crucial to design and synthesize thermally stable polymers that are less likely to decompose into combustible gaseous species under high-temperature conditions. Flame retardants can also be introduced to further reinforce the fire performance of polymers. In this review, the combustion process of organic matter, types of flame retardants, and common flammability testing methods are reviewed. Furthermore, the latest research trends in the use of versatile nanofillers to enhance the fire performance of polymeric materials are discussed with an emphasis on their underlying action, advantages, and disadvantages. [ABSTRACT FROM AUTHOR]

Keywords: 2D materials; energy applications; environmental applications; exfoliation EN 2D materials energy applications environmental applications exfoliation 1 1 1 05/23/20 20200520 NES 200520 B The exfoliation of 2D materials b into single or few layers can be achieved by external chemical and/or physical driving forces. For more details see the Review by H. Kim, H. Yoon et al. on page 6360 ff. GLO:OLD/20may20:chem202082963-toc-0001.jpg PHOTO (COLOR): . gl GLO:OLD/20may20:chem202082963-toc-0001.jpg PHOTO (COLOR): . gl 2D materials, energy applications, environmental applications, exfoliation. [Extracted from the article]