Controlling vertical phase separation of the active layer to enable efficient exciton dissociation and charge carrier transport is crucial to boost power conversion efficiencies (PCEs) of ...pseudoplanar heterojunction (PPHJ) organic solar cells (OSCs). However, how to optimize the vertical phase separation of PPHJ OSCs via molecule design is rarely reported yet. Herein, ternary polymerization strategy is employed to develop a series of polymer donors, DL1‐DL4, and regulate their solubility, molecular aggregation, molecular orientation, and miscibility, thus efficiently manipulating vertical phase separation in PPHJ OSCs. Among them, DL1 not only has enhanced solubility, inhibited molecular aggregation and partial edge‐on orientation to facilitate acceptor molecules, Y6, to permeate into polymer layer and increase donor/acceptor interfaces, but also sustains high crystallinity and appropriate miscibility with Y6 to acquire ordered molecular packing, thus achieving optimized vertical phase separation to well juggle exciton dissociation and charge transport in PPHJ devices. Therefore, DL1/Y6 based PPHJ OSCs gain the best exciton dissociation probability, highest charge carrier mobilities and weakest charge recombination, and thus afford an impressive PCE of 19.10%, which is the record value for terpolymer donors. It demonstrates that ternary polymerization is an efficient method to optimize vertical phase separation in PPHJ OSCs for high PCEs.
Ternary polymerization strategy is employed to manipulate the vertical phase separation in pseudoplanar heterojunction (PPHJ) organic solar cells (OSCs). The terpolymer DL1, with enhanced solubility, partial edge‐on orientation, and high crystallinity, endows DL1/Y6 PPHJ blend film with the optimized vertical phase separation. Therefore, DL1/Y6 based PPHJ OSCs afford an impressive PCE of 19.10%, which is the record for terpolymer donors.
Single‐component silk‐on‐silk microcapsules based on a layer‐by‐layer approach demonstrate the fabrication of highly permeable microcapsules with controlled permeability, porosity, and shell ...thickness. The formation of monodisperse robust capsules is afforded as a result of the formation of a β‐sheet‐rich structure of the absorbed silk proteins and hydrophobic–hydrophobic interactions.
•We developed highly sensitive optical fibre biosensor based on long period grating.•Biosensor is modified with silica core gold shell nanoparticles using layer-by-layer method.•Detection of ...Streptavidin and Immunoglobulin M is reported.•The limit of detection of 0.86 pg/mm2 and 22 pg/mm2 is reported of streptavidin and Immunoglobulin M.•The properties of the proposed sensor can be tailored simply by changing the ligand.
An optical fibre long period grating (LPG) biosensor is appealing in the detection of biomolecules because of the high sensitivity, label-free and real-time measurement. The miniaturized size, ability of remote sensing and immunity to electromagnetic interference of the LPG biosensor provide various possibility of single-point sensing in situations such as point of care diagnostics and in vivo measurement. Two optical fibre LPG based biosensors are reported for detection of streptavidin (SV) and immunoglobulin M (IgM) respectively. The LPG is coated with a film containing three layers of Poly(allylamine hydrochloride)/gold coated silica nanoparticles via the layer-by-layer method. Biotin is covalently bonded to the surface of the gold shell by means of the formation of an amide bonds for detection of streptavidin. The concentration of SV in water for detection varied from 1.25 nM to 2.7 μM. The LPG sensor, operating close to the phase matching condition shows a high sensitivity of 3.88 (ng/mm2)−1 and a detection limit of 0.86 pg/mm2 for the detection of SV. The limit of detection is 22 times lower than previously demonstrated with this type of sensor. The developed IgM sensor has the same configuration of film but has anti-IgM embedded on the LPG instead of biotin, demonstrating versatility of the sensing platform. This was used for the detection of human IgM with concentrations from 15.6 μg/ml to 1 mg/ml. The LPG sensor exhibits a sensitivity of 11 nm (ng/mm2)−1 for the detection of IgM with a detection limit of 15 pg/mm2. The developed highly sensitive IgM sensor shows the potential application of clinical point of care for detection of lower concentration of IgM in vitro. The proposed biosensor exhibits high sensitivity and rapid detection of low concentrations biomolecules from the small size of SV to the large size of IgM.
•Wood-based cellulose fibers are used to prepare porous network.•Plate-like, rod-like and spherical particles are used as coating components.•The nanocoating produces a protective barrier on ...individual cellulose fibers.•Unique nanoarchitectures result in self-extinguishing and decrease of heat release rates.
Wood-based cellulose fibers were used to prepare porous, low density and wet-stable fiber networks (FN). Multilayer coatings consisting of chitosan (CH), sodium hexametaphosphate (SHMP) and inorganic nanoparticles comprising of either sodium montmorillonite (MMT), sepiolite (SEP) or colloidal silica (SNP) were deposited by the layer-by-layer (LbL) technique onto FNs in an effort to impart flame-retardancy. A simulated fire scenario measured by cone calorimetry showed that five quadlayers (QL) of CH/SHMP/CH/MMT, CH/SHMP/CH/SEP and CH/SHMP/CH/SNP can produce significant reduction in peak heat release rate (pkHRR). In detail, the coating containing SEP showed the largest reduction of the pkHRR by 47% relative to the uncoated FN. MMT and SEP coated FNs were also able to self-extinguish fire and to retain their shapes after direct exposure to a methane flame. This study hence shows that the LbL assembly is a highly effective way to impart flame-retardant properties to this new type of porous FN.
Topping it off: Layer‐by‐layer growth was used to produce a highly oriented crystalline surface coordination polymer made up of copper dithiooxamide complexes (see scheme; SAM=self‐assembled ...monolayer). This example demonstrates that layer‐by‐layer growth in the liquid phase can produce a highly crystalline system even in difficult cases.
Layer‐by‐layer adsorption of polygenic polyelectrolytes is a promising method of treatment in which multilayers are formed on the inner arterial wall (see scheme). An advantage of this technique, ...which has already proved successful in animal models, is that it is very simple to apply, in contrast to in situ polymerization, which requires irradiation with UV light. Furthermore, it is rapid and allows the incorporation of active drugs in the layer.
An optical fibre long period grating sensor coated with three layers of poly (allylamine hydrochloride) and silica core gold shell nanoparticles was developed for the detection of human IgM. Three ...different concentrations of IgM suspension (19nM, 83nM and 0.3 μM) were detected. The sensor response time is less than 8 minutes and the binding of IgM can be observed dynamically at a concentration of 0.3 μM. The binding constant of IgM on the LPG sensor is 23.9 (pM) -1 based on the fitting of the Langmuir adsorption isotherm. The sensitivity of the LPG sensor is calculated as 11 nm/ (ng/mm 2 ) with a limit of detection of 0.0218 ng/mm 2 .
The HKUST-1 metal-organic framework (MOF) was selected because of the large internal surface area, excellent stability and known properties. Mechanical strain is generated upon the adsorption of ...analytes into the MOF; it is proportional to concentration and is a function of adsorbed species. Piezoresistive microcantilevers serve as a transduction mechanism to convert surface strain into electrical signals. N-doped piezoresistive cantilever arrays were fabricated with ten structures per die. Thin films of HKUST-1 were grown at room temperature using layer-by-layer techniques. Dry nitrogen was used as a carrier gas to expose devices to varying concentrations of 12 different volatile organic compounds (VOCs). Results show that stress-induced piezoresistive microcantilever array sensors with MOF coatings can provide a highly sensitive and reversible sensing mechanism for water vapour and methanol. Characteristic response features allow discrimination based on shape, response time constants and magnitude of response for other VOCs. Devices provided reliable data and proved durable over 18 months of testing. The key advantages of this type of sensor are higher sensitivity with a microporous MOFs, reversible response, α single chip sensing system and low power operation.
Herein, polyelectrolyte capsules containing anti-inflammatory drug indomethacin were formed using layer-by-layer strategy, which involves alternative deposition of oppositely charged ...polyelectrolytes, such as poly(acrylic acid) and poly(ethyleneimine) (or chitosan) onto the drug substrate. Two variants of encapsulation have been implemented: direct deposition of polyelectrolytes onto indomethacin dispersed in water at рН 6, and preliminary formation of soft matrix by solubilization of indomethacin in micellar solutions of cationic surfactants. The inclusion of indomethacin into nanosized polyelectrolyte capsules (hydrodynamic diameter of three- and five- layered capsules is 90–180 nm) has given a new form of indomethacin with the drug content of 0.20–0.25%, which exceeds its limiting solubility in water nearly by the factor of 40. The choice of materials and procedures used for preparation of capsules, as well as the number of polyelectrolyte layers that form shell has provided the control of the drug release from capsule and resulted in the design of pharmaceutical dosage forms with long-lasting effect.
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•Polyelectrolyte nanocapsules (≤200 nm) were formed through LbL technique.•A new bioavailable form of indomethacin have been obtained.•Encapsulation of indomethacin exceeds its limiting solubility in water by 40 times.•Dispersed loads serve as a template for the capsule fabrication and control their properties.
A new functionalization method to modify capacitive electrolyte–insulator–semiconductor (EIS) structures with nanofilms is presented. Layers of polyallylamine hydrochloride (PAH) and graphene oxide ...(GO) with the compound polyaniline:poly(2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid) (PANI:PAAMPSA) are deposited onto a p‐Si/SiO2 chip using the layer‐by‐layer technique (LbL). Two different enzymes (urease and penicillinase) are separately immobilized on top of a five‐bilayer stack of the PAH:GO/PANI:PAAMPSA‐modified EIS chip, forming a biosensor for detection of urea and penicillin, respectively. Electrochemical characterization is performed by constant capacitance (ConCap) measurements, and the film morphology is characterized by atomic force microscopy (AFM) and scanning electron microscopy (SEM). An increase in the average sensitivity of the modified biosensors (EIS–nanofilm–enzyme) of around 15% is found in relation to sensors, only carrying the enzyme but without the nanofilm (EIS–enzyme). In this sense, the nanofilm acts as a stable bioreceptor onto the EIS chip improving the output signal in terms of sensitivity and stability.
Sensing properties toward pH, urea, and penicillin detection of nanostructured films of polyallylamine hydrochloride (PAH) and graphene oxide (GO) with the compound polyaniline:poly(2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid) (PANI:PAAMPSA), deposited onto a p‐Si/SiO2 chip using the layer‐by‐layer technique (LbL) and a capacitive electrolyte–insulator–semiconductor (EIS) structure as a detection platform, are reported.
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