Transport properties of doped conjugated polymers (CPs) have been widely analyzed with the Gaussian disorder model (GDM) in conjunction with hopping transport between localized states. These models reveal that even in highly doped CPs, a majority of carriers are still localized because dielectric permittivity of CPs is well below that of inorganic materials, making Coulomb interactions between carriers and dopant counterions much more pronounced. However, previous studies within the GDM did not consider the role of screening the dielectric interactions by carriers.
View Article and Find Full Text PDFWhile nonwoven fabrics have existed for several decades, their usage in personal protective equipment (PPE) has been met with a rapid surge of demands, in part due to the recent COVID-19 pandemic. This review aims to critically examine the current state of nonwoven PPE fabrics by exploring (i) the material constituents and processing steps to produce fibers and bond them, and (ii) how each fabric layer is integrated into a textile, and how the assembled textiles are used as PPE. Firstly, filament fibers are manufactured via dry, wet, and polymer-laid fiber spinning methods.
View Article and Find Full Text PDFCurrent approaches for off-grid power separate the processes for energy conversion from energy storage. With the right balance between the electronic and ionic conductivity and a semiconductor that can absorb light in the solar spectrum, we can combine energy harvesting with storage into a single photoelectrochemical energy storage device. We report here such a device, a halide perovskite-based photorechargeable supercapacitor.
View Article and Find Full Text PDFCopper iodide (CuI) is a promising material for use as hole-transport layers in electronic devices due to their solution processability and efficient hole conductivity. CuI has a rich chemistry with halide salts and solvents to which it may be exposed during device fabrication. Thus, care must be taken during device fabrication when CuI is used.
View Article and Find Full Text PDFBackground: Healthy gut microbiota is important for prognosis in cow's milk allergy (CMA). The application of synbiotics (specific pre- and probiotics) in extensively hydrolyzed formulae (eHFs) is a relatively new concept.
Aims: To evaluate a synbiotic-containing, whey-based eHF (SeHF) with galacto-oligosaccharides, fructo-oligosaccharides, and bifidobacterium breve M-16V in infants with CMA.
Conjugated polymers need to be doped to increase charge carrier density and reach the electrical conductivity necessary for electronic and energy applications. While doping increases carrier density, Coulomb interactions between the dopant molecules and the localized carriers are poorly screened, causing broadening and a heavy tail in the electronic density-of-states (DOS). The authors examine the effects of dopant-induced disorder on two complimentary charge transport properties of semiconducting polymers, the Seebeck coefficient and electrical conductivity, and demonstrate a way to mitigate them.
View Article and Find Full Text PDFd-Tagatose, a potential low calorific substitute for sucrose, can be produced by bioconversion of d-galactose catalysed by l-arabinose isomerase. l-Arabinose isomerase from Shewanella sp. ANA-3 is unique for its ability to catalyse bioconversion reactions under mesophilic conditions.
View Article and Find Full Text PDFHybrid organic-inorganic perovskites have shown incredible promise as active materials for photovoltaic devices, but their instability to light remains a significant roadblock in realizing these applications. Changing the organic cation has been shown to affect light-induced degradation. As a strategy for increasing the stability of these materials, we replaced varying percentages of methylammonium ion in the archetypical methylammonium lead iodide (MAPbI) hybrid organic-inorganic perovskite with three significantly larger organic ammonium cations: imidazolium, dimethylammonium, and guanidinium.
View Article and Find Full Text PDFMolecular motors have evolved to transduce chemical energy from ATP into mechanical work to drive essential cellular processes, from muscle contraction to vesicular transport. Dysfunction of these motors is a root cause of many pathologies necessitating the need for intrinsic control over molecular motor function. Herein, we demonstrate that positional isomerism can be used as a simple and powerful tool to control the molecular motor of muscle, myosin.
View Article and Find Full Text PDFACS Appl Mater Interfaces
February 2020
Organic-nanoparticle-based solar cells have drawn great attention due to their eco-friendly and environmentally friendly fabrication procedure. However, these surfactant-stabilized nanoparticles suffer open-circuit voltage loss due to charge trapping and poor extraction rate at the polymer cathode interface. Here, we have investigated the origin of voltage loss and charge trapping in surfactant-stabilized nanoparticle-based devices.
View Article and Find Full Text PDFCorrection for 'The use of ion-selective membranes to study cation transport in hybrid organic-inorganic perovskites' by Emily C. Smith et al., Phys.
View Article and Find Full Text PDFUsing a methylammonium selective membrane in conjunction with electrochemical impedance spectroscopy, we measured ion migration in methylammonium lead triiodide (MAPbI) with a millisecond (ms) time constant under illumination. These values were consistent with the reported values of ionic conduction in thin-film perovskite solar cells. We monitored an electrochemical impedance response arising from ionic conductivity through MAPbI and a methylammonium selective layer.
View Article and Find Full Text PDFA significant challenge in the rational design of organic thermoelectric materials is to realize simultaneously high electrical conductivity and high induced-voltage in response to a thermal gradient, which is represented by the Seebeck coefficient. Conventional wisdom posits that the polymer alone dictates thermoelectric efficiency. Herein, we show that doping - in particular, clustering of dopants within conjugated polymer films - has a profound and predictable influence on their thermoelectric properties.
View Article and Find Full Text PDFThis work examines the feasibility of fuelling biodiesel derived from Eichhornia crassipes in a compression ignition engine. This work also proposes water hyacinth biodiesel (WHB) as a potential alternative energy source since the above species is available extensively in freshwater, marine, and aquatic ecosystems throughout the world. WHB was blended with petroleum diesel fuel at various volume proportions of 10%, 20%, 30%, 40%, and 100% and their properties were analyzed as per ASTM standards for its application as biofuel.
View Article and Find Full Text PDFOrganic materials have attracted recent interest as thermoelectric (TE) converters due to their low cost and ease of fabrication. We examine the effects of disorder on the TE properties of semiconducting polymers based on the Gaussian disorder model (GDM) for site energies while employing Pauli's master equation approach to model hopping between localized sites. Our model is in good agreement with experimental results and a useful tool to study hopping transport.
View Article and Find Full Text PDFPersistent n-doped conjugated polymers were achieved by doping the electron accepting PDNDIV and PFNDIV polymers with ionic (TBACN) or neutral (TDAE) dopants. The great electron affinities, as indicated by the low LUMO levels of PDNDIV (-4.09 eV) and PFNDIV (-4.
View Article and Find Full Text PDFBackground: The prevalence and time trends of food allergy change during childhood depending on the age of the child and the type of food.
Objective: To study prevalence and longitudinal trends in food allergy from birth to 18 years in an unselected birth cohort in the Isle of Wight.
Method: Information on food allergy was collected at ages 1, 2, 4, 10 and 18 years from the Isle of Wight Birth Cohort (n = 1456).
Energy densities of ~510 J/g (max: 698 J/g) have been achieved in azobenzene-based syndiotactic-rich poly(methacrylate) polymers. The processing solvent and polymer-solvent interactions are important to achieve morphologically optimal structures for high-energy density materials. This work shows that morphological changes of solid-state syndiotactic polymers, driven by different solvent processings play an important role in controlling the activation energy of Z-E isomerization as well as the shape of the DSC exotherm.
View Article and Find Full Text PDFWe synthesized distorted octahedral (T') molybdenum ditelluride (MoTe2) and investigated its vibrational properties with Raman spectroscopy, density functional theory, and symmetry analysis. Compared to results from the high-temperature centrosymmetric monoclinic (T'mo) phase, four new Raman bands emerge in the low-temperature orthorhombic (T'or) phase, which was recently predicted to be a type II Weyl semimetal. Crystal-angle-dependent, light-polarization-resolved measurements indicate that all the observed Raman peaks belong to two categories: those vibrating along the zigzag Mo atomic chain (z-modes) and those vibrating in the mirror plane (m-modes) perpendicular to the zigzag chain.
View Article and Find Full Text PDFACS Appl Mater Interfaces
March 2016
Perovskite-containing tandem solar cells are attracting attention for their potential to achieve high efficiencies. We demonstrate a series connection of a ∼ 90 nm thick perovskite front subcell and a ∼ 100 nm thick polymer:fullerene blend back subcell that benefits from an efficient graded recombination layer containing a zwitterionic fullerene, silver (Ag), and molybdenum trioxide (MoO3). This methodology eliminates the adverse effects of thermal annealing or chemical treatment that occurs during perovskite fabrication on polymer-based front subcells.
View Article and Find Full Text PDFThe aim of the present work is to design and construct an ex vivo bioreactor system to assess the real time viability of vascular tissue. Porcine carotid artery as a model tissue was used in the ex vivo bioreactor setup to monitor its viability under physiological conditions such as oxygen, pressure, temperature, and flow. The real time tissue viability was evaluated by monitoring tissue metabolism through a fluorescent indicator "resorufin.
View Article and Find Full Text PDFSolar cells fabricated using alkyl ammonium metal halides as light absorbers have the right combination of high power conversion efficiency and ease of fabrication to realize inexpensive but efficient thin film solar cells. However, they degrade under prolonged exposure to sunlight. Herein, we show that this degradation is quasi-reversible, and that it can be greatly lessened by simple modifications of the solar cell operating conditions.
View Article and Find Full Text PDFACS Appl Mater Interfaces
October 2014
3,6-Bis(N,N-dianisylamino)-fluoren-9-ylidene malononitrile (FMBDAA36) was used as an electron donor material in solution-processed organic photovoltaic devices with configuration ITO/PEDOT:PSS/(1:3[w/w] FMBDAA36:PC71BM)/LiF/Al to give power conversion efficiencies up to 4.1% with open circuit voltage VOC = 0.89 V, short circuit current JSC = 10.
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