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Cracks are common in nature. Cracking is known as an irreversible and uncontrollable process. To control the cracking patterns, many researchers have proposed methods to prepare notches for stress localization on films. In this work, we investigate a method of controlling cracks by making microscale pyramid patterns that have notches between the pyramids. After preparing pyramid patterns consisting of colloidal particles with organic residue, we annealed them to induce volume shrinkage and cracking between the pyramids. We studied the effect of film thickness on cracking and the generation of rectangular fragments consisting of multiple pyramids. The area of rectangular fragments was in good agreement with the results of scaling analysis. The concept of controlling cracks by imprinting notches on a film and the relationship with the film thickness can guide the study of cracking phenomena.

Inverse vulcanization provides a simple, solvent-free method for the preparation of high sulfur content polymers using elemental sulfur, a byproduct of refining processes, as feedstock. Despite the successful demonstration of sulfur polymers from inverse vulcanization in optical, electrochemical, and self-healing applications, the mechanical properties of these materials have remained limited. We herein report a one-step inverse vulcanization using allyl glycidyl ether, a heterobifunctional comonomer. The copolymerization, which proceeds via reactive compatibilization, gives an epoxy cross-linked sulfur polymer in a single step, as demonstrated through isothermal kinetic experiments and solid-state 13C NMR spectroscopy. The resulting high sulfur content (≥50 wt%) polymers exhibited tensile strength at break in the range of 10–60 MPa (70–50 wt% sulfur), which represents an unprecedentedly high strength for high sulfur content polymers from vulcanization. The resulting high sulfur content copolymer also exhibited extraordinary shape memory behavior along with shape reprogrammability attributed to facile polysulfide bond rearrangement., A one-step bulk polymerization between elemental sulfur and allyl glycidyl ether yields epoxy cross-linked sulfur polymers with unprecedentedly high mechanical strength and rapid shape-memory performance.

ConspectusAll-solid-state batteries (ASSBs) are considered to be a next-generation energy storage concept that offers enhanced safety and potentially high energy density. The identification of solid electrolytes (SEs) with high ionic conductivity was the stepping-stone that enabled the recent surge in activity in this research area. Among the various types of SEs, including those based on oxides, sulfides, polymers, and hybrids thereof, sulfide-based SEs have gained discernible attention owing to their exceptional room temperature ionic conductivity comparable even to those of their liquid electrolyte counterparts. Moreover, the good deformability of sulfide SEs renders them suitable for reducing the interfacial resistance between particles, thereby obviating the need for high-temperature sintering. Nevertheless, sulfide-based ASSB technology still remains at the research stage without any manufacturing schemes having been established. This state of affairs originates from the complex challenges presented by various aspects of these SEs: their weak stability in air, questions surrounding the exact combination of slurry solvent and polymeric binder for solution-based electrode fabrication, their high interfacial resistance resulting from solid particle contacts, and limited scalability with respect to electrode fabrication and cell assembly. In this Account, we review recent developments in which these issues were addressed by starting with the materials and moving on to processing, focusing on new trials. As for enhancing the air stability of sulfide SEs, strengthening the metal-sulfur bond based on the hard-soft acid-base (HSAB) theory has yielded the most notable results, although the resulting sacrificed energy density and weakened anode interface stability would need to be resolved. Novel electrode fabrication techniques that endeavor to overcome the critical issues originating from the use of sulfide SEs are subsequently introduced. The wet chemical coating process can take advantage of the know-how and facilities inherited from the more established lithium-ion batteries (LIBs). However, the dilemmatic matter of contention relating to the polarity mismatch among the slurry solvent, SE, and binder requires attention. Recent solutions to these problems involved the exploration of various emerging concepts, such as polarity switching during electrode fabrication, fine polarity tuning by accurate grafting, and infiltration of the electrode voids by a solution of the SE. The process of using a dry film with a fibrous binder has also raised interest, motivated by lowering the manufacturing cost, maintaining the environment, and boosting the volumetric energy density. Finally, optimization of the cell assembly and operation is reviewed. In particular, the application of external pressure to each unit cell has been universally adopted both in the fabrication step and during cell operation to realize high cell performance. The effect of pressurization is discussed by correlating it with the interface stability and robust interparticle contacts. Based on the significant progress that has been made thus far, we aim to encourage the battery community to engage their wide-ranging expertise toward advancing sulfide-based ASSBs that are practically feasible.

BACKGROUND: Various cell-culture systems have been used to evaluate drug toxicity in vitro. However, factors that affect cytotoxicity outcomes in drug toxicity evaluation systems remain elusive. In this study, we used multilayered sheets of cardiac-mimetic cells, which were reprogrammed from human fibroblasts, to investigate the effects of the layer number on drug cytotoxicity outcomes. METHODS: Cell sheets of cardiac-mimetic cells were fabricated by reprogramming of human fibroblasts into cardiac-mimetic cells via coculture with cardiac cells and electric stimulation, as previously described. Double-layered cell sheets were prepared by stacking the cell sheets. The mono- and double-layered cell sheets were treated with 5-fluorouracil (5-FU), an anticancer drug, in vitro. Subsequently, apoptosis and lipid peroxidation were analyzed. Furthermore, effects of cardiac-mimetic cell density on cytotoxicity outcomes were evaluated by culturing cells in monolayer at various cell densities. RESULTS: The double-layered cell sheets exhibited lower cytotoxicity in terms of apoptosis and lipid peroxidation than the mono-layered sheets at the same 5-FU dose. In addition, the double-layered cell sheets showed better preservation of mitochondrial function and plasma membrane integrity than the monolayer sheets. The lower cytotoxicity outcomes in the double-layered cell sheets may be due to the higher intercellular interactions, as the cytotoxicity of 5-FU decreased with cell density in monolayer cultures of cardiac-mimetic cells. CONCLUSION: The layer number of cardiac-mimetic cell sheets affects drug cytotoxicity outcomes in drug toxicity tests. The in vitro cellular configuration that more closely mimics the in vivo configuration in the evaluation systems seems to exhibit lower cytotoxicity in response to drug. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s13770-021-00363-y.

Chain exchange kinetics of the bottlebrush core micelles formed by poly(5-perfluorooctyl-2-norbornene-block-N-cyclohexyl-exo-norbornene-5,6-dicarboxyimide) (PF-b-PC) block copolymer in tetrahydrofuran (THF), selective for PC blocks, were investigated by time-resolved small-angle neutron scattering (TR-SANS). The bottlebrush PF core blocks are densely tethered with rigid fluoroalkyl side chains. Despite the unfavorable interaction between the PF cores and the medium, TR-SANS revealed that the chain exchange between the bottlebrush core micelles occurs within a measurable timescale (∼1 h) at 40 °C. The measured exchange kinetics were successfully described by the model based on the thermodynamic barrier for the core block extraction and the solvent plasticizing effect associated with partial swelling of the PF cores. This chain exchange rate is also partly attributed to the bottlebrush architecture of PF blocks, as supported by lower melt viscosities of PF homopolymers than those of the analogous fluorine-containing linear polymers. These results are discussed in terms of current understanding of molecular exchange between block copolymer micelles, and particular attention is paid to the issue of polymer architecture, given the bottlebrush type of the core block.

We report on the fabrication of wholly polymeric one-dimensional (1-D) photonic crystals (i.e., Bragg reflectors, Bragg mirrors) via solution processing for use in the near (NIR) and the short wave (SWIR) infrared spectrum (1–2 μm) with very high reflectance (R ∼ 90–97%). Facile fabrication of these highly reflective films was enabled by direct access to solution processable, ultrahigh refractive index polymers, termed, Chalcogenide Hybrid Inorganic/Organic Polymers (CHIPs). The high refractive index (n) of CHIPs materials (n = 1.75–2.10) allowed for the production of narrow band IR Bragg reflectors with high refractive index contrast (Δn ∼ 0.5) when fabricated with low n polymers, such as cellulose acetate (n = 1.47). This is the highest refractive index contrast (Δn ∼ 0.5) demonstrated for an all-polymeric Bragg mirror which directly enabled high reflectivity from films with 22 layers or less. Facile access to modular, thin, highly reflective films from inexpensive CHIPs materials offers a new route to ...

Optical technologies in the midwave and long wave infrared spectrum (MWIR, LWIR) are important systems for high resolution thermal imaging in near, or complete darkness. While IR thermal imaging has been extensively utilized in the defense sector, application of this technology is being driven toward emerging consumer markets and transportation. In this viewpoint, we review the field of IR thermal imaging and discuss the emerging use of synthetic organic and hybrid polymers as novel IR transmissive materials for this application. In particular, we review the critical role of elemental sulfur as a novel feedstock to prepare high refractive index polymers via inverse vulcanization and discuss the fundamental chemical insights required to impart improved IR transparency into these polymeric materials.

We report on the conformal coating of thickness-tunable multilayers directly onto the sulfur (S8) cathodes by the layer-by-layer (LbL) deposition for the significant improvement in the performances of Li–S batteries even without key additives (LiNO3) in the electrolyte. Poly(ethylene oxide) (PEO)/poly(acrylic acid) (PAA) multilayers on a single poly(allylamine hydrochloride) (PAH)/PAA priming bilayer, deposited on the S8 cathodes, effectively protected from the polysulfide leakage, while providing a Li+ ion diffusion channel. As a result, PAH/PAA/(PEO/PAA)3 multilayer-coated cathodes exhibited the highest capacity retention (806 mAh g–1) after 100 cycles at 0.5 C, as well as the high C-rate capability up to 2.0 C. Furthermore, the multilayer coating effectively mitigated the polysulfide shuttle effect in the absent of LiNO3 additives in the electrolyte.

We have developed the in situ fibrillation of κ-casein, employed as amyloid precursor, within multilayer films consisting of κ-casein and poly(acrylic acid) (PAA) prepared by the layer-by-layer (LbL) deposition. The fibrillation of κ-casein within the multilayered films is strongly dependent on the extent of intermolecular interactions between κ-casein and PAA. When films constructed initially at pH 3 were heat treated at the same pH, κ-casein did not transform into fibrils. However, when the films were subjected to heat treatment at pH 5, κ-casein was transformed into fibrils within multilayer films due to weakened intermolecular interactions between κ-casein and PAA. We also noted that the multilayer film was swollen at pH 5 by the charge imbalance within the film, which we believe gives enough mobility for κ-caseins to form fibrils with adjacent κ-caseins within the multilayer. The fibrils were found to be uniformly distributed across the entire film thickness, and the aspect ratio as well as the number density of fibrils increased as a function of incubation time. The present study reveals a strategy to realize in situ nanocomposites within LbL multilayer films simply by triggering the formation of protein fibrils by controlling the intermolecular interactions between amyloid precursors and polyelectrolytes (PEs).

When various optically and/or electronically active materials, such as conjugated polymers, perovskites, metals, and metal oxides, are confined at the nanoscale, they can exhibit unique nano-confined behavior that significantly differs from the behavior observed at the macroscale. Although controlled nano-confinement of functional materials can allow modulation of their electronic properties without the aid of any synthetic methodologies or additional chemical treatments, limited assembly approaches for nano-confinement and insufficient analytical tools for electronic characterization remain critical challenges in the development of novel optoelectronic materials and the investigation of their modulated properties. This review describes how the nano-confined features of organic and inorganic materials are related to the control and improvement of their optoelectronic properties. In particular, we focus on various assembly approaches for effective nano-confinement as well as methods for nano-electronic characterization. Then, we briefly present challenges and perspectives on the direction of nano-confinement in terms of the preparation of optoelectronic materials with desired functionalities. Furthermore, we believe that this review can provide a basis for developing and designing next-generation optoelectronics through nano-confinement.

Porous membranes play a critical role in in vitro heterogeneous cell coculture systems because they recapitulate the in vivo microenvironment to mediate physical and biochemical crosstalk between cells. While the conventionally available Transwell® system has been widely used for heterogeneous cell coculture, there are drawbacks to precise control over cell-cell interactions and separation for implantation. The size and numbers of the pores and the thickness of the porous membranes are crucial in determining the efficiency of paracrine signaling and direct junctions between cocultured cells, and significantly impact on the performance of heterogeneous cell cultures. These opportunities and challenges have motivated the design of advanced coculture platforms through improvement of the structural and functional properties of porous membranes.

The mechanical properties of injectable and thermo-responsive ABC triblock copolymer hydrogels are enhanced by the electrostatic attraction between oppositely charged moieties introduced in the mid-blocks. The triblock copolymers are composed of biodegradable poly(e-caprolactone) (PCL), hydrophilic cationic or anionic mid-block, and temperature-responsive poly(N-isopropylacrylamide) (PNIPAM) with quadruple hydrogen bonding units. PCL blocks and PNIPAM blocks form separate micellar cores, and the mid-blocks make a bridge between the cores. The dynamic nature and thermo-responsiveness of the PNIPAM block primarily endow the temperature- and shear-responsiveness to the hydrogel, and therefore make the hydrogel injectable and self-healable. In particular, the electrostatic attraction introduced in the mid-blocks results in the enhanced mechanical properties of the hydrogels. The dual-responsive hydrogel with the improved moduli will aid in designing soft materials in the field of biological and biomedical applications.

We present structural analysis of spherical diblock copolymer micelles where core blocks have bottlebrush architecture. The dependence of the core radius (Rcore) and the corona thickness (Lcorona) ...

We previously demonstrated that the efficiency of direct cardiac reprogramming from fibroblasts could be enhanced via mimicking of the in vivo cardiac microenvironment through coculture with cardiomyocytes and by providing electric cues. In the present study, we developed cell sheets using the direct cardiac reprogrammed cells and a nanothin, nanoporous poly(lactic-co-glycolic acid) membrane. Cell sheets were laid layer-by-layer and prevacularized with endothelial cells between the layers. These prevascularized, multilayered cell sheets were implanted on the epicardium of infarcted rat hearts, which led to an improvement in cardiac function and reduction in adverse cardiac remodeling post-myocardial infarction (MI). Thus, the in vivo mimicking direct cardiac reprogramming and prevascularization technique can enhance the efficiency of cell sheets in clinical applications and provide new opportunities to prevent heart failure following MI.

We report on a new strategy for preparing polymer–nanoparticle composite Faraday rotators for use in magnetic sensing and optical isolation. While most applications of Faraday rotators make use of inorganic garnet crystals, these are generally limited by low magneto-optical activity (low Verdet constants), high cost, and/or limited processing options. This has led to an interest in new materials with improved activity and processing characteristics. We have developed a new type of magneto-optical material based on polymer–nanoparticle composites that can be completely prepared by solution processing methods with tunable Verdet constants and device sensitivity. By exchanging native surface ligands on magneto-optically active CoFe2O4 nanocrystals with polymer compatible ligands, enhanced nanoparticle dispersion in processible polymer matrices was observed at up to 15 wt% inorganic loading. Employing a multilayer polymer film construct, functional Faraday rotator devices were prepared by simple sequential spin-coating of active nanocomposite and protective, barrier cellulose acetate layers. For these assemblies, magneto-optic activity and sensitivity are easily tuned through variation of nanoparticle feed and control of polymer film layers, respectively. These multilayered Faraday rotators show up to a 10-fold enhancement in Verdet constant compared to reference terbium gallium garnets at 1310 nm, opening new possibilities for the fabrication of “plastic garnets” as low cost alternatives to existing inorganic materials for use in the near-IR.

High-refractive-index sulfur-rich polymers with significantly improved thermal properties are prepared using divinylbenzene (DVB) as a comonomer in a modified, low-temperature inverse vulcanization with elemental sulfur. Differential scanning calorimetry and Fourier transform infrared studies reveal that under the modified inverse vulcanization conditions, homopolymerized DVB segments form, leading to high glass-transition temperatures (

Optical technologies in the long-wave infrared (LWIR) spectrum (7-14 μm) offer important advantages for high-resolution thermal imaging in near or complete darkness. The use of polymeric transmissive materials for IR imaging offers numerous cost and processing advantages but suffers from inferior optical properties in the LWIR spectrum. A major challenge in the design of LWIR-transparent organic materials is that nearly all organic molecules absorb in this spectral window which lies within the so-called IR-fingerprint region. We report on a new molecular-design approach to prepare high refractive index polymers with enhanced LWIR transparency. Computational methods were used to accelerate the design of novel molecules and polymers. Using this approach, we have prepared chalcogenide hybrid inorganic/organic polymers (CHIPs) with enhanced LWIR transparency and thermomechanical properties via inverse vulcanization of elemental sulfur with new organic co-monomers.

ABC triblock copolymers composed of hydrophobic poly(e-caprolactone) (PCL), zwitterionic poly(carboxybetaine methacrylate) midblock, and P(PEGMA-UPy0.15 ) containing supramolecular ureidopyrimidinone moieties, poly(e-caprolactone-block-carboxybetaine methacrylate-block-[poly(ethylene glycol) methyl ether methacrylate-co-(α-methacryloyl-ω-(6-(3-(6-methyl-4-oxo-1,4-dihydropyrimidin-2-yl)ureido)hexylcarbamoyloxy)poly(ethylene glycol))]), are investigated to achieve multifunctional antifreeze hydrogels. The PCL and P(PEGMA-UPy0.15 ) blocks induce the formation of physical network with a hierarchical nanostructure comprising hydrophobic PCL cores and supramolecular junctions, respectively. The super-hydrophilic nature of polyzwitterion midblocks and the confinement effect of the supramolecular junctions enhance the antifreeze performance, where the majority of water molecules remains supercooled below sub-zero temperature. The hydrogel relaxation characterized over a wide range of timescale reveals that the facile dynamics of the supramolecular junctions lead to the self-healing and injectability of the hydrogels. In conjunction with the biodegradable PCL cores, the antifreeze and rheological characteristics of the triblock copolymer hydrogels provide significant potential to use for cryo-preservable and bio-injectable drug storage and delivery.

Lithium–sulfur (Li–S) batteries by far offer higher theoretical energy density than that of the commercial lithium-ion battery counterparts, but suffer predominantly from an irreversible shuttling ...

Block copolymers (BCPs) under nanoscale confinement can self-assemble to form novel nanostructures that are not available in the bulk state. Particularly, the ordering process of block copolymers a...

Advance in wet chemistry enables the sophisticated design of nanocrystal quantum dots (QDs) and allows unprecedented color purity and brightness, promising their useful applications in a variety of...

Colloidal semiconductor nanocrystals, referred to as quantum dots (QDs), have unique and superb photophysical properties, promising a variety of applications ranging from optoelectronics and energy harvesting to agriculture. The last decade witnessed a tremendous advance in QDs and their successful debut in displays, and now, QDs are equipped with environmental benignity to expand their territory to everyday life. From this perspective, the current research status and future perspective of environmentally benign QDs as building blocks for light-generating and light-harvesting applications are provided. Also provided is an overview of the progress made in the chemistry (colloidal synthesis, surface chemistry, and heterostructuring) and in their photophysical and electrical properties from the viewpoint of their use in light-emitting or light-harvesting applications. Grounded on the current status of heavy-metal-free QDs compared with cutting-edge technologies, the perspective of environmentally benign QDs for practical use and future research directions is discussed.

In this paper, we report the synthesis and mesoporous film formation of hydrophobic rodlike poly( p-phenyleneethynylene)s (PPEs) and present porosity-dependent quenching studies using 1,3,5-trinitrotoluene (TNT) vapors. Nonsolvent vapor-induced phase separation was used to induce pore formation during film casting, and the concentration of PPEs in the casting solution was controlled carefully to prevent excimer formation. We found that the structures of the sidechains of the PPEs strongly influence the range of relative humidity at which controlled pore generation occurs, which could be rationalized from interfacial energies calculated from contact angle measurements. Porosity of the PPE films resulted in increased efficiency of fluorescence quenching toward TNT vapors, which previously required very thin films (below 5 nm) for sensing applications. The control of the porous structure as well as film thickness constitutes a promising strategy for enhancing the efficiency of chemosensors and in more general applications requiring fine-tuned polymer-gas interactions.

Recent developments in the polymerization of elemental sulfur and the preparation of functional Chalcogenide Hybrid Inorganic/Organic Polymers (CHIPs) are reviewed. CHIPs represent a class of polymers synthesized from elemental sulfur with the incorporation of inorganic chalcogenide components (S, Se, Te) into the organic polymeric backbones. Novel CHIP materials exhibit interesting optical, electrochemical and mechanical properties that lead to applications in thermal imaging, energy storage, self-healable materials and separation science. The emphasis of this review is on the key advances in the synthetic approaches to prepare functional polymeric sulfur-rich materials, with recent developments in synthesis, characterization, and application milestones being highlighted.

Recent studies of all-solid-state batteries (ASSBs) have identified sulfide-based electrolytes with comparable ionic conductivities as those of liquid counterparts. Nevertheless, solution-based manufacturing is unestablished, since it is challenging to find adhesive polymeric binders that can be dispersed in common solvents with sulfide electrolytes. Currently available binders exhibit insufficient electrode adhesion due to their low polarity and are compromised by the chemical stability of a slurry. Here, we report a thiol–ene click reaction used to graft styrene–butadiene-block-copolymer with carboxylic acid at an optimal concentration. With polarity tuning, the click binder results in a uniform electrode slurry without ruining the structure of the sulfide electrolytes, while enabling electrode adhesion 1.4 times as high as that of commercial lithium-ion battery electrodes. The click binder also allows ASSBs to deliver decent electrochemical performance, implying that fine polarity tuning of functional ...

We investigate the operational instability of quantum dot (QD)-based light-emitting diodes (QLEDs). Spectroscopic analysis on the QD emissive layer within devices in chorus with the optoelectronic and electrical characteristics of devices discloses that the device efficiency of QLEDs under operation is indeed deteriorated by two main mechanisms. The first is the luminance efficiency drop of the QD emissive layer in the running devices owing to the accumulation of excess electrons in the QDs, which escalates the possibility of nonradiative Auger recombination processes in the QDs. The other is the electron leakage toward hole transport layers (HTLs) that accompanies irreversible physical damage to the HTL by creating nonradiative recombination centers. These processes are distinguishable in terms of the time scale and the reversibility, but both stem from a single origin, the discrepancy between electron versus hole injection rates into QDs. Based on experimental and calculation results, we propose mechanistic models for the operation of QLEDs in individual quantum dot levels and their degradation during operation and offer rational guidelines that promise the realization of high-performance QLEDs with proven operational stability.

Recent research has built a consensus that the binder plays a key role in the performance of high‐capacity silicon anodes in lithium‐ion batteries. These anodes necessitate the use of a binder to maintain the electrode integrity during the immense volume change of silicon during cycling. Here, Zn2+–imidazole coordination crosslinks that are formed to carboxymethyl cellulose backbones in situ during electrode fabrication are reported. The recoverable nature of Zn2+–imidazole coordination bonds and the flexibility of the poly(ethylene glycol) chains are jointly responsible for the high elasticity of the binder network. The high elasticity tightens interparticle contacts and sustains the electrode integrity, both of which are beneficial for long‐term cyclability. These electrodes, with their commercial levels of areal capacities, exhibit superior cycle life in full‐cells paired with LiNi0.8Co0.15Al0.05O2 cathodes. The present study underlines the importance of highly reversible metal ion‐ligand coordination chemistries for binders intended for high capacity alloying‐based electrodes., Zn2+–imidazole coordination bonds, crosslinked with carboxymethyl cellulose in situ during electrode fabrication, are introduced as a polymeric binder for high‐capacity silicon anodes. The reversible metal–ligand bonds impart high elasticity to the binder network for keeping the electrode's integrity. The robust cycling performance under commercial levels of areal capacity highlights the usefulness of high elasticity involving metal–ligand bonds.

Quasi-type II heterostructured nanocrystals (NCs) have been of particular interest due to their great potential for controlling the interplay of charge carriers. However, the lack of material choices for quasi-type II NCs restricts the accessible emission wavelength from red to near-infrared (NIR), which hinders their use in light-emitting applications that demand a wide range of visible colors. Herein, we demonstrate a new class of quasi-type II nanoemitters formulated in ZnSe/ZnSe 1- X Te X /ZnSe seed/spherical quantum well/shell heterostructures (SQWs) whose emission wavelength ranges from blue to orange. In a given geometry, ZnSe 1- X Te X emissive layers grown between the ZnSe seed and the shell layer are strained to fit into the surrounding media, and thus, the lattice mismatch between ZnSe 1- X Te X and ZnSe is effectively alleviated. In addition, composition of the ZnSe 1- X Te X emissive layer and the dimension of the ZnSe shell layer are engineered to tailor the distribution and energy of electron and hole wave functions. Benefitting from the capabilities to tune the charge carriers on demand and to form defect-free heterojunctions, ZnSe/ZnSe 1- X Te X /ZnSe/ZnS NCs show near-unity photoluminescence quantum yield ( PL QY > 90 % ) in a broad range of emission wavelengths (peak PL from 450 nm to 600 nm). Finally, we exemplify dichromatic white NC-based light-emitting diodes (NC-LEDs) employing the mixed layer of blue- and yellow-emitting ZnSe/ZnSe 1- X Te X /ZnSe/ZnS SQW NCs.

The unparalleled theoretical specific energy of lithium-sulfur (Li-S) batteries has attracted considerable research interest from within the battery community. However, most of the long cycling results attained thus far relies on using a large amount of electrolyte in the cell, which adversely affects the specific energy of Li-S batteries. This shortcoming originates from the low solubility of polysulfides in the electrolyte. Here, 1,3-dimethyl-2-imidazolidinone (DMI) is reported as a new high donor electrolyte for Li-S batteries. The high solubility of polysulfides in DMI and its activation of a new reaction route, which engages the sulfur radical (S3 •- ), enables the efficient utilization of sulfur as reflected in the specific capacity of 1595 mAh g-1 under lean electrolyte conditions of 5 μLelectrolyte mgsulfur -1 . Moreover, the addition of LiNO3 stabilizes the lithium metal interface, thereby elevating the cycling performance to one of the highest known for high donor electrolytes in Li-S cells. These engineered high donor electrolytes are expected to advance Li-S batteries to cover a wide range of practical applications, particularly by incorporating established strategies to realize the reversibility of lithium metal electrodes.

Colorless, transparent polymer thin films with n > 1.9 were prepared through vapor deposition polymerization of elemental sulfur., High refractive index polymers (HRIPs) have recently emerged as an important class of materials for use in a variety of optoelectronic devices including image sensors, lithography, and light-emitting diodes. However, achieving polymers having refractive index exceeding 1.8 while maintaining full transparency in the visible range still remains formidably challenging. Here, we present a unique one-step vapor-phase process, termed sulfur chemical vapor deposition, to generate highly stable, ultrahigh refractive index (n > 1.9) polymers directly from elemental sulfur. The deposition process involved vapor-phase radical polymerization between elemental sulfur and vinyl monomers to provide polymer films with controlled thickness and sulfur content, along with the refractive index as high as 1.91. Notably, the HRIP thin film showed unprecedented optical transparency throughout the visible range, attributed to the absence of long polysulfide segments within the polymer, which will serve as a key component in a wide range of optical devices.

Hyaluronic acid (HA)–graphene oxide (GO) conjugates, with a high loading of photosensitizers (PS; Ce6), were developed as a cancer cell targeted and photoactivity switchable nanoplatform for photodynamic therapy (PDT). HA–GO conjugates with size below 100 nm were first prepared by the chemical conjugation between ADH-modified HA and fractionated GO sheets with size relevant for drug delivery. Before evaluating the drug delivery efficacies, their chemical structure, morphology, and biocompatibility were characterized by 1H NMR, UV, TGA, AFM, DLS and MTT assays. The physical adsorption of Ce6 onto HA–GO nanocarriers was mainly due to the π–π stacking as well as hydrophobic interactions. It was demonstrated by CLSM and FACS that the cellular internalization of the HA–GO/Ce6 nanohybrids was much more effective when compared with free Ce6, which was also found to be significantly influenced by the co-treatment with an excess amount of HA polymers, illustrating their active targeting to HA receptors overexpressed on cancer cells. The photoactivity of Ce6 adsorbed on HA–GO nanocarriers was mostly quenched in aqueous solution to ensure biocompatibility, but was quickly recovered after the release of Ce6 from HA–GO nanocarriers upon cellular uptake. As a result, the PDT efficiency of the HA–GO/Ce6 nanohybrids was remarkably improved ∼10 times more than that of free Ce6, as well demonstrated in both MTT and LIVE/DEAD assays.

Reactive poly(pentafluorophenyl acrylate) (PPFPA)-grafted surfaces offer a versatile platform to immobilize biomolecules. Here, we utilize PPFPA-grafted surface and double-stranded RNA (dsRNA) recognizing J2 antibody to construct a universal virus detection platform with enhanced sensitivity. PPFPA on silicon substrates is prepared, and surface hydrophilicity is modulated by partial substitution of the pentafluorophenyl units with poly(ethylene glycol). Following dsRNA antibody immobilization, the prepared surfaces can distinguish long dsRNAs from single-stranded RNAs of the same length and short dsRNAs. As long dsRNAs are common byproducts of viral transcription/replication, these surfaces can detect the presence of different kinds of viruses without prior knowledge of their genomic sequences. To increase dsRNA detection sensitivity, a two-step method is devised where the captured dsRNAs are visualized with multiple fluorophore-tagged J2 antibodies. We show that the developed platform can differentiate foreign long dsRNAs from cellular dsRNAs and other biomolecules present in the cell lysate. Moreover, when tested against cells infected with hepatitis A or C viruses, both viruses are successfully detected using a single platform. Our study shows that the developed PPFPA platform immobilized with J2 antibody can serve as a primary diagnostic tool to determine the infection status for a wide range of viruses.

Sulfide‐based all‐solid‐state batteries (ASSBs) have been featured as promising alternatives to the current lithium‐ion batteries (LIBs) mainly owing to their superior safety. Nevertheless, a solution‐based scalable manufacturing scheme has not yet been established because of the incompatible polarity of the binder, solvent, and sulfide electrolyte during slurry preparation. This dilemma is overcome by subjecting the acrylate (co)polymeric binders to protection−deprotection chemistry. Protection by the tert‐butyl group allows for homogeneous dispersion of the binder in the slurry based on a relatively less polar solvent, with subsequent heat‐treatment during the drying process to cleave the tert‐butyl group. This exposes the polar carboxylic acid groups, which are then able to engage in hydrogen bonding with the active cathode material, high‐nickel layered oxide. Deprotection strengthens the electrode adhesion such that the strength equals that of commercial LIB electrodes, and the key electrochemical performance parameters are improved markedly in both half‐cell and full‐cell settings. The present study highlights the potential of sulfide‐based ASSBs for scalable manufacturing and also provides insights that protection−deprotection chemistry can generally be used for various battery cells that suffer from polarity incompatibility among multiple electrode components.

The high specific capacity in excess of 200 mAh g-1 and low dependence on cobalt have enhanced the research interest on nickel-rich layered metal oxides as cathode materials for lithium-ion batteries for electric vehicles. Nonetheless, their poor cycle life and thermal stability, resulting from the occurrence of cation mixing between the transition-metal (TM) and lithium ions, are yet to be fully addressed to enable the widespread and reliable use of these materials. Here, we report a two-dimensional (2D) pyrazine-linked covalent organic framework (namely, Pyr-2D) as a coating material for nickel-rich layered cathodes to mitigate unwanted TM dissolution and interfacial reactions. The Pyr-2D coating layer, especially the 2D planar morphology and conjugated atomic configuration of Pyr-2D, protects the electrode surface effectively during cycling without sacrificing the electric conductivity of the host material. As a result, Pyr-2D-coated nickel-rich layered cathodes exhibited superior cyclability, rate performance, and thermal stability. The present study highlights the potential ability of 2D conjugated covalent organic frameworks to improve the key electrochemical properties of emerging battery electrodes.

Evolution of favourable nanomorphology which can withstand external stimuli is a critical issue for efficient and stable organic solar cells. Here, we demonstrate a novel strategy for the stabilization of nanomorphology of organic solar cells by inducing polymeric nanowire network structures. Thermal annealing of poly(3- hexylthiophene-2,5-diyl) nanowires, highly crystalline, 1-dimensional structures held together through interchain π-π stacking, led to the formation of nanowire network structures confirmed through small angle neutron scattering measurements. The physically interconnected network structures form robust electron donor domains and impose confinement which suppresses the aggregation of the electron acceptor, [6,6]-phenyl-C61-butylric acid methyl ester. Organic solar cells having the nanowire network structures showed increased power conversion efficiencies and dramatically enhanced thermal stability compared to bulk heterojunction (BHJ) and non-network nanowire-based devices. Furthermore, the performance of the nanowire network-based devices was inversely related to the size of the networks, attesting to the significance of nanoconfined geometry formed within nanowire network structures.

For most of natural hybrid materials, the shape of mineral crystals is controlled by natural polymers (e.g., proteins) to provide designated and unique physical properties and functions. Synthetic hybrid materials, which show comparable performance to the natural ones, require well-controlled crystal growth. In particular, the dynamic process including adsorption of the polymers on the crystal surface plays a significant role. We investigated CaSO4·0.5H2O crystallization in the presence of linear or particulate charged macromolecules, which can interact electrostatically with the crystals. Not only the static factors such as concentration and charge fraction but also the diffusion dynamics of the charged macromolecules were found crucial to involve the complete inhibition of growth and the subsequent shape transition of the crystals. This leads to the elucidation of semiquantitative relationships between dynamic factors such as the diffusion of macromolecules and the rate of crystal growth to the growth i...