bluuebunny/crossref_metadata_2025 huggingface dataset:
Neurofilament light chain serum levels correlate with 10‐year MRI outcomes in multiple sclerosis
Authors: Chitnis Tanuja , Gonzalez Cindy , Healy Brian C. , Saxena Shrishti , Rosso Mattia , Barro Christian , Michalak Zuzanna , Paul Anu , Kivisakk Pia , Diaz‐Cruz Camilo , Sattarnezhad Neda , Pierre Isabelle V. , Glanz Bonnie I. , Tomic Davorka , Kropshofer Harald , Häring Dieter , Leppert David , Kappos Ludwig , Bakshi Rohit , Weiner Howard L. , Kuhle Jens
Published: October 2018

Objective

To assess the value of annual serum neurofilament light (NfL) measures in predicting 10‐year clinical and MRI outcomes in multiple sclerosis (MS).

Methods

We identified patients in our center's Comprehensive Longitudinal Investigations in MS at Brigham and Women's Hospital (CLIMB) study enrolled within 5 years of disease onset, and with annual blood samples up to 10 years (n = 122). Serum NfL was measured using a single molecule array (SIMOA) assay. An automated pipeline quantified brain T2 hyperintense lesion volume (T2LV) and brain parenchymal fraction (BPF) from year 10 high‐resolution 3T MRI scans. Correlations between averaged annual NfL and 10‐year clinical/MRI outcomes were assessed using Spearman's correlation, univariate, and multivariate linear regression models.

Results

Averaged annual NfL values were negatively associated with year 10 BPF, which included averaged year 1–5 NfL values (unadjusted P < 0.01; adjusted analysis P < 0.01), and averaged values through year 10. Linear regression analyses of averaged annual NfL values showed multiple associations with T2LV, specifically averaged year 1–5 NfL (unadjusted P < 0.01; adjusted analysis P < 0.01). Approximately 15–20% of the BPF variance and T2LV could be predicted from early averaged annual NfL levels. Also, averaged annual NfL levels with fatigue score worsening between years 1 and 10 showed statistically significant associations. However, averaged NfL measurements were not associated with year 10 EDSS, SDMT or T25FW in this cohort.

Interpretation

Serum NfL measured during the first few years after the clinical onset of MS contributed to the prediction of 10‐year MRI brain lesion load and atrophy.
Qualitative Exploration of Triangulated, Shared Decision‐Making in Rheumatoid Arthritis
Authors: Binder‐Finnema Pauline , Dzurilla Kathryn , Hsiao Betty , Fraenkel Liana
Published: October 2018

Objective

Treat‐to‐target implementation in rheumatoid arthritis (RA) requires a shared decision‐making (SDM) process. However, ability to pay is a major determinant of patient choice, but how this factor affects SDM is under‐explored.

Methods

Visits at 4 RA clinics during which patients faced a decision to change their treatment were audiotaped between May 2016 and June 2017. Audiotapes were transcribed verbatim and analyzed using qualitative framework analysis.

Results

A total of 156 visits were analyzed. Most patients with RA, except those with effective insurance coverage, had deliberations disrupted or sidelined by third‐party insurance providers having power to authorize the preferred disease‐modifying antirheumatic drug choice. This triangulated SDM complicated efficiency in deliberations and timely treatment and was a barrier to shared engagement about health risks and symptom improvement typically found in patient‐provider dyads.

Conclusion

Rheumatology care providers should aim to incorporate treatment costs and ability to pay into their deliberations so that individualized out‐of‐pocket estimates can be considered during triangulated SDM at the point‐of‐care.
Cyclic Stiffness Modulation of Cell‐Laden Protein–Polymer Hydrogels in Response to User‐Specified Stimuli Including Light
Authors: Liu Luman , Shadish Jared A. , Arakawa Christopher K. , Shi Kevin , Davis Jennifer , DeForest Cole A.
Published: October 2018

Although mechanical signals presented by the extracellular matrix are known to regulate many essential cell functions, the specific effects of these interactions, particularly in response to dynamic and heterogeneous cues, remain largely unknown. Here, a modular semisynthetic approach is introduced to create protein–polymer hydrogel biomaterials that undergo reversible stiffening in response to user‐specified inputs. Employing a novel dual‐chemoenzymatic modification strategy, fusion protein‐based gel crosslinkers are created that exhibit stimuli‐dependent intramolecular association. Linkers based on calmodulin yield calcium‐sensitive materials, while those containing the photosensitive light, oxygen, and voltage sensing domain 2 (LOV2) protein give phototunable constructs whose moduli can be cycled on demand with spatiotemporal control about living cells. These unique materials are exploited to demonstrate the significant role that cyclic mechanical loading plays on fibroblast‐to‐myofibroblast transdifferentiation in 3D space. The moduli‐switchable materials should prove useful for studies in mechanobiology, providing new avenues to probe and direct matrix‐driven changes in 4D cell physiology.
Manipulation of Single Cells Using a Ferromagnetic Nanorod Cluster Actuated by Weak AC Magnetic Fields
Authors: Zhu Lu , Huang Weijie , Yang Fengchang , Yin Lei , Liang Shenxuan , Zhao Wujun , Mao Leidong , Yu Xiaozhong (John) , Qiao Rui , Zhao Yiping
Published: October 2018

A unique noncontact single cell manipulation technique based on the actuation of magnetic nanorods (MNRs) or clusters (MCs) by nonuniform alternating magnetic fields (nuAMFs) is demonstrated. Compared to the actuation of MNRs/MCs by conventional magnetophoresis, the motion of MNRs/MCs actuated by nuAMFs can be tuned by additional parameters including the shape of MNRs/MCs and the frequency of the applied magnetic fields. The manipulation of a single cell by an actuated MNR/MC are divided into five stages, i.e., approaching, pushing, carrying, dragging, and releasing. The interactions between the MNR/MC and the cell in these stages are investigated in detail both experimentally and numerically. Other applications of cell manipulation, such as concentrating cells at target locations and accumulating MNRs/MCs onto a single cell, are also demonstrated. The single cell manipulation system is simple, low‐cost, and low‐power consumption, and helps advance the state‐of‐the‐art of single‐particle manipulation.
Gas Humidification Impact on the Properties and Performance of Perovskite‐Type Functional Materials in Proton‐Conducting Solid Oxide Cells
Authors: Wang Wei , Medvedev Dmitry , Shao Zongping
Published: October 2018

Fuel cells and electrolysis cells as important types of energy conversion devices can be divided into groups based on the electrolyte material. However, solid oxide cells (SOCs) based on conventional oxygen‐ion conductors are limited by several issues, such as high operating temperature, the difficulty of hydrogen purification from water, and inferior stability. To avoid these problems, proton‐conducting oxides are proposed as electrolytes for SOCs in electrolysis and fuel cell modes. Since water vapor partial pressure (pH2O) is one of the main parameters determining the proton concentration in proton‐conducting oxides (characteristics of which can be either improved or deteriorated), the pH2O control is extremely important for the optimization of the devices' performance and stability. This review provides an overview of the research progresses made for proton‐conducting SOCs, especially for the impact of gas humidification on the operability and performance. Fundamental understanding of the main processes in proton‐conducting SOCs and design principles for the key components are summarized and discussed. The trends, challenges, and future directions that exist in this dynamic field are also pointed out. This review will inspire interest from various disciplines and provide some useful guidelines for future development of proton‐conductor‐based energy storage and conversion systems.
Biochemical Gradients to Generate 3D Heterotypic‐Like Tissues with Isotropic and Anisotropic Architectures
Authors: Canadas Raphaël F. , Ren Tanchen , Marques Alexandra P. , Oliveira Joaquim M. , Reis Rui L. , Demirci Utkan
Published: October 2018

Anisotropic 3D tissue interfaces with functional gradients found in nature are replicated in vitro for drug development and tissue engineering. Even though different fabrication techniques, based on material science engineering and microfluidics, are used to generate such microenvironments, mimicking the native tissue gradient is still a challenge. Here, the fabrication of 3D structures are described with linear/random porosity and gradient distribution of hydroxyapatite microparticles which are combined with a gradient of growth factors generated by a dual chamber for the development of heterotypic‐like tissues. The hydroxyapatite gradient is formed by applying a thermal ramp from the first to the second gel layer, and the porous architecture is controlled through ice templating. A 3D osteochondral (OC) tissue model is developed by codifferentiating fat pad adipose‐derived stem cells. Osteogenic and chondrogenic markers expression is spatially controlled, as it occurs in the native osteochondral unit. Additionally, a prevasculature is spatially induced by the perfusion of proangiogenic medium in the bone‐like region, as observed in the native subchondral bone. Thus, in this study, precise spatial control is developed over cell/tissue phenotype and formation of prevasculature which opens up possibilities for the study of complex tissues interfaces, with broader applications in drug testing and regenerative medicine.
Super Charge Separation and High Voltage Phase in NaxMnO2
Authors: Chen Xi , Wang Yichao , Wiaderek Kamila , Sang Xiahan , Borkiewicz Olaf , Chapman Karena , LeBeau James , Lynn Jeffrey , Li Xin
Published: October 2018

NaxMnO2 shows Mn3+ and Mn4+ charge separation with the charge stripe ordering upon Na deintercalation at x = 5/8. In this paper it is shown that, surprisingly, at lower Na compositions of 5/8 > x ≥ 1/18 the phase evolution pathway of NaxMnO2 upon Na deintercalation shows a unique phenomenon of super charge separation, where the Mn3+ and Mn4+ ions fully charge‐separate into charge superplanes formed by succession of charge stripes in the third dimension. The Mn3+ superplanes attract Na ions electronically, and dominate the antiferromagnetic interactions in NaMnO2. Na ions in Mn3+ superplanes also naturally pillar the MnO2 layers to form the unusual O1 phases with large interlayer distances at x < 1/3, which dominates the unique electrochemical behavior of NaMnO2.
Energy Storage in Metallic Glasses via Flash Annealing
Authors: Küchemann Stefan , Derlet Peter M. , Liu Chaoyang , Rosenthal Daniel , Sparks Gregory , Larson William S. , Maaß Robert
Published: October 2018

When the temperature rises in a kinetically frozen and out‐of‐equilibrium system, such as a structural glass, thermal activation usually drives a relaxation to a lower enthalpy state. This is the essence of the ubiquitous thermal ageing of glassy materials below the glass transition temperature. Here, it is shown that an ultrafast temperature rise without subsequent quenching can elevate the system to a higher enthalpy state, thereby erasing the relaxation history. The key of this temperature‐driven rejuvenation is a fast‐heating rate (flash annealing) that brings the glass into a temperature regime above the glass transition within less than a millisecond. Here, the structure is entropically driven towards the liquid state, lowering its free energy, but raising its enthalpy. Subsequent cooling freezes the increased enthalpy before the liquid state is reached, thereby leading to a global energy storage. This ultrafast rejuvenation process is demonstrated for a Zr‐based metallic glass, combining calorimetry, fast in‐situ X‐ray diffraction, and atomistic simulations, showing a tenfold increase in stored enthalpy via flash annealing.
A Microfluidic‐Based Model for Spatially Constrained Culture of Intestinal Microbiota
Authors: Pajoumshariati Seyed Ramin , Azizi Morteza , Zhang Shiying , Dogan Belgin , Simpson Kenneth W. , Abbaspourrad Alireza
Published: October 2018

Perturbation of the microbiome is implicated in the pathogenesis of many human ailments, including inflammatory bowel diseases such as Crohn's disease (CD). Recapitulating the microbiome associated with health and disease necessitates controlling the composition of multiple bacterial species. This is difficult to achieve in vitro due to the overgrowth of bacterial species over time. Here, a microfluidic‐based model incorporating bacteria‐embedded hydrogel microfibers for the coculture of human enteric bacteria is introduced. Employing bacterial species and strains associated with CD, it is shown that the hydrogel‐based bacteria‐embedded microfiber model is physically and mechanically robust, and tunable. Metabolite analysis of the medium in both mono‐ and coculture revealed the interfiber exchange of soluble mediators and their impact on the growth of different bacterial species. This novel approach should enhance the ability to decipher contact‐independent cross‐talk within the polymicrobial intestinal luminal environment, and its impact on the intestinal epithelium.
Large‐Area, Semitransparent, and Flexible All‐Polymer Photodetectors
Authors: Xu Xiaofeng , Zhou Xiaobo , Zhou Ke , Xia Yuxin , Ma Wei , Inganäs Olle
Published: October 2018

Photodetectors, converting optical signals from specific wavelengths to electrical signals, have many applications on photoimaging, optical communication, and environmental monitoring. Solution‐processed organic photodetectors (OPDs) based on organic materials emerge promise especially for wearable electronics and smart buildings. In this work, new all‐polymer photodetectors (all‐PPDs) are developed based on bulk‐heterojunction active layers which incorporate a donor polymer and an acceptor polymer. The inverted all‐PPDs exhibit outstanding external quantum efficiency over 70%, low dark current density (J
d) of 1.1 × 10−8 A cm−2, and high detectivity (D*) over 3.0 × 1012 Jones with planar response over the entire visible range. It is one of the best‐performing all‐PPDs reported so far and is also comparable with many organic and inorganic photodetectors. By using lamination technique, large‐area, semitransparent, flexible, and “fully” polymeric photodetectors are successfully fabricated for the first time, with D* over 1011 Jones for double‐side light detection. The results highlight the great potential for producing high‐performance all‐PPDs by taking advantages of various device architecture and solution‐processing techniques.
An Unusual Red Carbon Nitride to Boost the Photoelectrochemical Performance of Wide Bandgap Photoanodes
Authors: Yang Yilong , Wang Songcan , Jiao Yalong , Wang Zhiliang , Xiao Mu , Du Aijun , Li Yongli , Wang Jinshu , Wang Lianzhou
Published: October 2018

Tuning the bandgap of a semiconductor to achieve strong band‐to‐band visible light absorption is highly desirable but challenging for photocatalysis. This work presents a facile molten‐salt‐assisted route to prepare red‐colored polymerized carbon nitride (RPCN) nanosheets with a remarkable redshifted absorption and narrowed bandgap of 1.9 eV. Both experimental findings and theoretical calculations reveal that alkali heteroatoms are effective to tune the surface and electronic structures of carbon nitride, resulting in significantly reduced bandgap and excellent solubility. The RPCN‐sensitized TiO2 nanorod‐based photoanode generates an impressive photocurrent density of ≈2.33 mA cm−1 at 1.23 V versus reversible hydrogen electrode under Air Mass 1.5 G illumination without any cocatalyst, which is 2.6 folds higher than that of the bare TiO2 photoanode. The new findings in this work could inspire the electronic structure engineering of semiconductor photocatalysts to greatly enhance the visible light absorption and provide a generic strategy to enhance the photoelectrochemical performance of wide‐bandgap semiconductor photoelectrodes.
The Role of Dielectric Screening in Organic Shortwave Infrared Photodiodes for Spectroscopic Image Sensing
Authors: Wu Zhenghui , Zhai Yichen , Yao Weichuan , Eedugurala Naresh , Zhang Song , Huang Lifeng , Gu Xiaodan , Azoulay Jason D. , Ng Tse Nga
Published: October 2018

This work examines an additive approach that increases dielectric screening to overcome performance challenges in organic shortwave infrared (SWIR) photodiodes. The role of the high‐permittivity additive, camphoric anhydride, in the exciton dissociation and charge collection processes is revealed through measurements of transient photoconductivity and electrochemical impedance. Dielectric screening reduces the exciton binding energy to increase exciton dissociation efficiency and lowers trap‐assisted recombination loss, in the absence of any morphological changes for two polymer variants. In the best devices, the peak internal quantum efficiency at 1100 nm is increased up to 66%, and the photoresponse extends to 1400 nm. The SWIR photodiodes are integrated into a 4 × 4 pixel imager to demonstrate tissue differentiation and estimate the fat‐to‐muscle ratio through noninvasive spectroscopic analysis.
Epitaxial Growth of 1D Atomic Chain Based Se Nanoplates on Monolayer ReS2 for High‐Performance Photodetectors
Authors: Qin Jing‐Kai , Qiu Gang , He Wen , Jian Jie , Si Meng‐Wei , Duan Yu‐Qin , Charnas Adam , Zemlyanov Dmitry Y. , Wang Hai‐Yan , Shao Wen‐Zhu , Zhen Liang , Xu Cheng‐Yan , Ye Peide D.
Published: October 2018

Mixed‐dimensional (0D, 1D, and 3D) heterostructures based on 2D layered materials have been proven as a promising candidate for future nanoelectronics and optoelectronics applications. In this work, it is demonstrated that 1D atomic chain based Se nanoplates (NPs) can be epitaxially grown on monolayer ReS2 by a chemical transport reaction, thereby creating an interesting mixed‐dimensional Se/ReS2 heterostructure. A unique epitaxial relationship is observed with the (110) planes of the Se NPs parallel to the corresponding ReS2 (010) planes. Experimental and theoretical studies reveal that the Se NPs could conjugate with underlying monolayer ReS2 via strong chemical hybridization at heterointerface, which is expected to originate from the intrinsic defects of ReS2. Remarkably, photodetectors based on Se/ReS2 heterostructures exhibit ultrahigh detectivity of up to 8 × 1012 Jones, and also show a fast response time of less than 10 ms. These results illustrate the great advantage of directly integrated 1D Se based nanostructure on planar semiconducting ReS2 films for optoelectronic applications. It opens up a feasible way to obtain mixed‐dimensional heterostructures with atomic interfacial contact by epitaxial growth.
Metal‐Organic Framework Encapsulation Preserves the Bioactivity of Protein Therapeutics
Authors: Wang Congzhou , Sudlow Gail , Wang Zheyu , Cao Sisi , Jiang Qisheng , Neiner Alicia , Morrissey Jeremiah J. , Kharasch Evan D. , Achilefu Samuel , Singamaneni Srikanth
Published: October 2018

Protein therapeutics are prone to lose their structure and bioactivity under various environmental stressors. This study reports a facile approach using a nanoporous material, zeolitic imidazolate framework‐8 (ZIF‐8), as an encapsulant for preserving the prototypic protein therapeutic, insulin, against different harsh conditions that may be encountered during storage, formulation, and transport, including elevated temperatures, mechanical agitation, and organic solvent. Both immunoassay and spectroscopy analyses demonstrate the preserved chemical stability and structural integrity of insulin offered by the ZIF‐8 encapsulation. Biological activity of ZIF‐8‐preserved insulin after storage under accelerated degradation conditions (i.e., 40 °C) is evaluated in vivo using a diabetic mouse model, and shows comparable bioactivity to refrigeration‐stored insulin (−20 °C). It is also demonstrated that ZIF‐8‐preserved insulin has low cytotoxicity in vitro and does not cause side effects in vivo. Furthermore, ZIF‐8 residue can be completely removed by a simple purification step before insulin administration. This biopreservation approach is potentially applicable to diverse protein therapeutics, thus extending the benefits of advanced biologics to resource‐limited settings and underserved populations/regions.
Dynamic PEG–Peptide Hydrogels via Visible Light and FMN‐Induced Tyrosine Dimerization
Authors: Liu Hung‐Yi , Nguyen Han D. , Lin Chien‐Chi
Published: October 2018

Photoresponsive hydrogels have become invaluable 3D culture matrices for mimicking aspects of the extracellular matrix. Recent efforts have focused on using ultraviolet (UV) light exposure and multifunctional macromers to induce secondary hydrogel crosslinking and dynamic matrix stiffening in the presence of cells. This contribution reports the design of a novel yet simple dynamic poly(ethylene glycol)–peptide hydrogel system through flavin mononucleotide (FMN) induced di‐tyrosine crosslinking. These di‐tyrosine linkages effectively increase hydrogel crosslinking density and elastic modulus. In addition, the degree of stiffening in hydrogels at a fixed PEG macromer content can be readily tuned by controlling FMN concentration or the number of tyrosine residues built‐in to the peptide linker. Furthermore, tyrosine‐bearing pendant biochemical motifs can be spatial‐temporally patterned in the hydrogel network via controlling light exposure through a photomask. The visible light and FMN‐induced tyrosine dimerization process produces a cytocompatible and physiologically relevant degree of stiffening, as shown by changes of cell morphology and gene expression in pancreatic cancer and stromal cells. This new dynamic hydrogel scheme should be highly desirable for researchers seeking a photoresponsive hydrogel system without complicated chemical synthesis and secondary UV light irradiation.
A Highly Porous Copper Electrocatalyst for Carbon Dioxide Reduction
Authors: Lv Jing‐Jing , Jouny Matthew , Luc Wesley , Zhu Wenlei , Zhu Jun‐Jie , Jiao Feng
Published: October 2018

Electrochemical reduction of carbon dioxide (CO2) is an appealing approach toward tackling climate change associated with atmospheric CO2 emissions. This approach uses CO2 as the carbon feedstock to produce value‐added chemicals, resulting in a carbon‐neutral (or even carbon‐negative) process for chemical production. Many efforts have been devoted to the development of CO2 electrolysis devices that can be operated at industrially relevant rates; however, limited progress has been made, especially for valuable C2+ products. Herein, a nanoporous copper CO2 reduction catalyst is synthesized and integrated into a microfluidic CO2 flow cell electrolyzer. The CO2 electrolyzer exhibits a current density of 653 mA cm−2 with a C2+ product selectivity of ≈62% at an applied potential of −0.67 V (vs reversible hydrogen electrode). The highly porous electrode structure facilitates rapid gas transport across the electrode–electrolyte interface at high current densities. Further investigations on electrolyte effects reveal that the surface pH value is substantially different from the pH of bulk electrolyte, especially for nonbuffering near‐neutral electrolytes when operating at high currents.
Metal Oxide Nanocomposites: A Perspective from Strain, Defect, and Interface
Authors: Chen Aiping , Su Qing , Han Hyungkyu , Enriquez Erik , Jia Quanxi
Published: October 2018

Vertically aligned nanocomposite thin films with ordered two phases, grown epitaxially on substrates, have attracted tremendous interest in the past decade. These unique nanostructured composite thin films with large vertical interfacial area, controllable vertical lattice strain, and defects provide an intriguing playground, allowing for the manipulation of a variety of functional properties of the materials via the interplay among strain, defect, and interface. This field has evolved from basic growth and characterization to functionality tuning as well as potential applications in energy conversion and information technology. Here, the remarkable progress achieved in vertically aligned nanocomposite thin films from a perspective of tuning functionalities through control of strain, defect, and interface is summarized.
Construction of Hierarchically Porous Nanoparticles@Metal–Organic Frameworks Composites by Inherent Defects for the Enhancement of Catalytic Efficiency
Authors: Meng Fanchen , Zhang Suoying , Ma Lu , Zhang Weina , Li Matthew , Wu Tianpin , Li Hang , Zhang Tao , Lu Xiaohua , Huo Fengwei , Lu Jun
Published: October 2018

Nanoparticles@metal–organic frameworks (MOFs) composites have attracted considerable attention in recent years due to the prominent selective catalytic activity. However, it is highly desirable to develop a simple and universal way to settle the trade‐off between the catalytic efficiency and selectivity. Herein, by employing the thermal instability of inherent defects, hierarchically porous Pt@UiO‐66‐NH2, Pt@UiO‐66, Pt@ZIF‐8, and Au@ZIF‐8 are successfully constructed after annealing at an appropriate temperature, respectively. The generated mesopores in the MOFs can be located around the external nanoparticle to retain the MOF shell for catalytic selectivity. Finally, when tested in olefin hydrogenation, Pt@UiO‐66‐NH2 shows significantly improved catalytic rate and enhanced dynamic selectivity.
Carbon Nanotube Porins in Amphiphilic Block Copolymers as Fully Synthetic Mimics of Biological Membranes
Authors: Sanborn Jeremy R. , Chen Xi , Yao Yun‐Chiao , Hammons Joshua A. , Tunuguntla Ramya H. , Zhang Yuliang , Newcomb Christina C. , Soltis Jennifer A. , De Yoreo James J. , Van Buuren Anthony , Parikh Atul N. , Noy Aleksandr
Published: October 2018

Biological membranes provide a fascinating example of a separation system that is multifunctional, tunable, precise, and efficient. Biomimetic membranes, which mimic the architecture of cellular membranes, have the potential to deliver significant improvements in specificity and permeability. Here, a fully synthetic biomimetic membrane is reported that incorporates ultra‐efficient 1.5 nm diameter carbon nanotube porin (CNTPs) channels in a block‐copolymer matrix. It is demonstrated that CNTPs maintain high proton and water permeability in these membranes. CNTPs can also mimic the behavior of biological gap junctions by forming bridges between vesicular compartments that allow transport of small molecules.
Rhenium‐Doped and Stabilized MoS2 Atomic Layers with Basal‐Plane Catalytic Activity
Authors: Yang Shi‐Ze , Gong Yongji , Manchanda Priyanka , Zhang Yu‐Yang , Ye Gonglan , Chen Shuangming , Song Li , Pantelides Sokrates T. , Ajayan Pulickel M. , Chisholm Matthew F. , Zhou Wu
Published: October 2018

The development of stable and efficient hydrogen evolution reaction (HER) catalysts is essential for the production of hydrogen as a clean energy resource. A combination of experiment and theory demonstrates that the normally inert basal planes of 2D layers of MoS2 can be made highly catalytically active for the HER when alloyed with rhenium (Re). The presence of Re at the ≈50% level converts the material to a stable distorted tetragonal (DT) structure that shows enhanced HER activity as compared to most of the MoS2‐based catalysts reported in the literature. More importantly, this new alloy catalyst shows much better stability over time and cycling than lithiated 1T‐MoS2. Density functional theory calculations find that the role of Re is only to stabilize the DT structure, while catalysis occurs primarily in local Mo‐rich DT configurations, where the HER catalytic activity is very close to that in Pt. The study provides a new strategy to improve the overall HER performance of MoS2‐based materials via chemical doping.
Merits and Challenges of Ruddlesden–Popper Soft Halide Perovskites in Electro‐Optics and Optoelectronics
Authors: Chen Zhizhong , Guo Yuwei , Wertz Esther , Shi Jian
Published: October 2018

Following the rejuvenation of 3D organic–inorganic hybrid perovskites, like CH3NH3PbI3, (quasi)‐2D Ruddlesden–Popper soft halide perovskites R2An−1PbnX3n+1 have recently become another focus in the optoelectronic and photovoltaic device community. Although quasi‐2D perovskites were first introduced to stabilize optoelectronic/photovoltaic devices against moisture, more interesting properties and device applications, such as solar cells, light‐emitting diodes, white‐light emitters, lasers, and polaritonic emission, have followed. While delicate engineering design has pushed the performance of various devices forward remarkably, understanding of the fundamental properties, especially the charge‐transfer process, electron–phonon interactions, and the growth mechanism in (quasi)‐2D halide perovskites, remains limited and even controversial. Here, after reviewing the current understanding and the nexus between optoelectronic/photovoltaic properties of 2D and 3D halide perovskites, the growth mechanisms, charge‐transfer processes, vibrational properties, and electron–phonon interactions of soft halide perovskites, mainly in quasi‐2D systems, are discussed. It is suggested that single‐crystal‐based studies are needed to deepen the understanding of the aforementioned fundamental properties, and will eventually contribute to device performance.
Borohydride‐Scaffolded Li/Na/Mg Fast Ionic Conductors for Promising Solid‐State Electrolytes
Authors: Cuan Jing , Zhou You , Zhou Tengfei , Ling Shigang , Rui Kun , Guo Zaiping , Liu Huakun , Yu Xuebin
Published: October 2018

Borohydride solid‐state electrolytes with room‐temperature ionic conductivity up to ≈70 mS cm−1 have achieved impressive progress and quickly taken their place among the superionic conductive solid‐state electrolytes. Here, the focus is on state‐of‐the‐art developments in borohydride solid‐state electrolytes, including their competitive ionic‐conductive performance, current limitations for practical applications in solid‐state batteries, and the strategies to address their problems. To open, fast Li/Na/Mg ionic conductivity in electrolytes with BH4
− groups, approaches to engineering borohydrides with enhanced ionic conductivity, and later on the superionic conductivity of polyhedral borohydrides, their correlated conductive kinetics/thermodynamics, and the theoretically predicted high conductive derivatives are discussed. Furthermore, the validity of borohydride pairing with coated oxides, sulfur, organic electrodes, MgH2, TiS2, Li4Ti5O12, electrode materials, etc., is surveyed in solid‐state batteries. From the viewpoint of compatible cathodes, the stable electrochemical windows of borohydride solid‐state electrolytes, the electrode/electrolyte interface behavior and battery device design, and the performance optimization of borohydride‐based solid‐state batteries are also discussed in detail. A comprehensive coverage of emerging trends in borohydride solid‐state electrolytes is provided and future maps to promote better performance of borohydride SSEs are sketched out, which will pave the way for their further development in the field of energy storage.
Polymethacrylamide and Carbon Composites that Grow, Strengthen, and Self‐Repair using Ambient Carbon Dioxide Fixation
Authors: Kwak Seon‐Yeong , Giraldo Juan Pablo , Lew Tedrick Thomas Salim , Wong Min Hao , Liu Pingwei , Yang Yun Jung , Koman Volodymyr B. , McGee Melissa K. , Olsen Bradley D. , Strano Michael S.
Published: October 2018

Plants accumulate solid carbon mass and self‐repair using atmospheric CO2 fixation from photosynthesis. Synthetic materials capable of mimicking this property can significantly reduce the energy needed to transport and repair construction materials. Here, a gel matrix containing aminopropyl methacrylamide (APMA), glucose oxidase (GOx), and nanoceria‐stabilized extracted chloroplasts that is able to grow, strengthen, and self‐repair using carbon fixation is demonstrated. Glucose produced from the embedded chloroplasts is converted to gluconolactone (GL) via GOx, polymerizing with APMA to form a continuously expanding and strengthening polymethacrylamide. The extracted spinach chloroplasts exhibit enhanced stability and produce 12 µg GL mg−1 Chl h−1 after optimization of the temporal illumination conditions and the glucose efflux rate, with the insertion of chemoprotective nanoceria inside the chloroplasts. This system achieves an average growth rate of 60 µm3 h−1 per chloroplast under ambient CO2 and illumination over 18 h, thickening with a shear modulus of 3 kPa. This material can demonstrate self‐repair using the exported glucose from chloroplasts and chemical crosslinking through the fissures. These results point to a new class of materials capable of using atmospheric CO2 fixation as a regeneration source, finding utility as self‐healing coatings, construction materials, and fabrics.
1D Sub‐Nanotubes with Anatase/Bronze TiO2 Nanocrystal Wall for High‐Rate and Long‐Life Sodium‐Ion Batteries
Authors: Chen Biao , Meng Yuhuan , Xie Fangxi , He Fang , He Chunnian , Davey Kenneth , Zhao Naiqin , Qiao Shi‐Zhang
Published: October 2018

The development of 1D nanostructures with enhanced material properties has been an attractive endeavor for applications in energy and environmental fields, but it remains a major research challenge. Herein, this work demonstrates a simple, gel‐derived method to synthesize uniform 1D elongated sub‐nanotubes with an anatase/bronze TiO2 nanocrystal wall (TiO2 SNTs). The transformation mechanism of TiO2 SNTs is studied by various ex situ characterization techniques. The resulting 1D nanostructures exhibit, synchronously, a high aspect ratio, open tubular interior, and anatase/bronze nanocrystal TiO2 wall. This results in excellent properties of electron/ion transport and reaction kinetics. Consequently, as an anode material for sodium‐ion batteries (SIBs), the TiO2 SNTs display an ultrastable long‐life cycling stability with a capacity of 107 mAh g−1 at 16 C after 4000 cycles and a high‐rate capacity of 94 mAh g−1 at 32 C. This a high‐rate and long‐life performance is superior to any report on pure TiO2 for SIBs. This work provides new fundamental information for the design and fabrication of inorganic structures for energy and environmental applications.
A Lithium–Sulfur Battery using a 2D Current Collector Architecture with a Large‐Sized Sulfur Host Operated under High Areal Loading and Low E/S Ratio
Authors: Li Matthew , Zhang Yining , Bai Zhengyu , Liu Wen Wen , Liu Tongchao , Gim Jihyeon , Jiang Gaopeng , Yuan Yifei , Luo Dan , Feng Kun , Yassar Reza S. , Wang Xiaolei , Chen Zhongwei , Lu Jun
Published: October 2018

While backless freestanding 3D electrode architectures for batteries with high loading sulfur have flourished in the recent years, the more traditional and industrially turnkey 2D architecture has not received the same amount of attention. This work reports a spray‐dried sulfur composite with large intrinsic internal pores, ensuring adequate local electrolyte availability. This material offers good performance with a electrolyte content of 7 µL mg−1 at high areal loadings (5–8 mg cm−2), while also offering the first reported 2.8 µL mg−1 (8 mg cm−2) to enter into the second plateau of discharge and continue to operate for 20 cycles. Moreover, evidence is provided that the high‐frequency semicircle (i.e., interfacial resistance) is mainly responsible for the often observed bypassing of the second plateau in lean electrolyte discharges.
Polymer‐Based Synthetic Routes to Carbon‐Based Metal‐Free Catalysts
Authors: Gottlieb Eric , Matyjaszewski Krzysztof , Kowalewski Tomasz
Published: October 2018

Carbons are increasingly important as possible alternatives to expensive metal catalysts owing to the wide range of chemical properties they can exhibit and the growing set of synthetic routes available to produce them. This progress report discusses the process of making catalytic carbons from polymeric precursors, focusing on mechanisms of carbonization and how the polymer structures and synthetic procedures affect the resulting carbons. In considering what is necessary to move laboratory catalytic carbons to industrial and commercial applications, the cost and complexity to produce them are a considerable challenge to overcome. Industrially produced carbons are typically made from biopolymers such as lignin while many of the catalytic carbons studied in literature are from synthetic polymers. Thus, studying polymer‐derived carbons can provide insights into the carbonization process and the properties of catalytic carbons, which can subsequently be translated to improve biopolymer‐derived carbons in an economical way. Aspects of polymer carbonization discussed include carbonization mechanisms, effects of crosslinkers, polymer microstructure, heteroatom control, and effects of nanostructuring.
Balancing Charge Storage and Mobility in an Oligo(Ether) Functionalized Dioxythiophene Copolymer for Organic‐ and Aqueous‐ Based Electrochemical Devices and Transistors
Authors: Savagian Lisa R. , Österholm Anna M. , Ponder James F. , Barth Katrina J. , Rivnay Jonathan , Reynolds John R.
Published: October 2018

This work presents a soluble oligo(ether)‐functionalized propylenedioxythiophene (ProDOT)‐based copolymer as a versatile platform for a range of high‐performance electrochemical devices, including organic electrochemical transistors (OECTs), electrochromic displays, and energy‐storage devices. This polymer exhibits dual electroactivity in both aqueous and organic electrolyte systems, redox stability for thousands of redox cycles, and charge‐storage capacity exceeding 80 F g−1. As an electrochrome, this material undergoes full colored‐to‐colorless optical transitions on rapid time scales (<2 s) and impressive electrochromic contrast (Δ%T > 70%). Incorporation of the polymer into OECTs yields accumulation‐mode devices with an ION/OFF current ratio of 105, high transconductance without post‐treatments, as well as competitive hole mobility and volumetric capacitance, making it an attractive candidate for biosensing applications. In addition to being the first ProDOT‐based OECT active material reported to date, this is also the first reported OECT material synthesized via direct(hetero)arylation polymerization, which is a highly favorable polymerization method when compared to commonly used Stille cross‐coupling. This work provides a demonstration of how a single ProDOT‐based polymer, prepared using benign polymerization chemistry and functionalized with highly polar side chains, can be used to access a range of highly desirable properties and performance metrics relevant to electrochemical, optical, and bioelectronic applications.
Multiscale Structural Engineering of Ni‐Doped CoO Nanosheets for Zinc–Air Batteries with High Power Density
Authors: Li Yue‐Jiao , Cui Lan , Da Peng‐Fei , Qiu Kang‐Wen , Qin Wen‐Jing , Hu Wen‐Bin , Du Xi‐Wen , Davey Kenneth , Ling Tao , Qiao Shi‐Zhang
Published: October 2018

Zinc–air batteries offer a possible solution for large‐scale energy storage due to their superhigh theoretical energy density, reliable safety, low cost, and long durability. However, their widespread application is hindered by low power density. Herein, a multiscale structural engineering of Ni‐doped CoO nanosheets (NSs) for zinc–air batteries with superior high power density/energy density and durability is reported for the first time. In micro‐ and nanoscale, robust 2D architecture together with numerous nanopores inside the nanosheets provides an advantageous micro/nanostructured surface for O2 diffusion and a high electrocatalytic active surface area. In atomic scale, Ni doping significantly enhances the intrinsic oxygen reduction reaction activity per active site. As a result of controlled multiscale structure, the primary zinc–air battery with engineered Ni‐doped CoO NSs electrode shows excellent performance with a record‐high discharge peak power density of 377 mW cm−2, and works stable for >400 h at 5 mA cm−2. Rechargeable zinc–air battery based on Ni‐doped CoO NSs affords an unprecedented small charge–discharge voltage of 0.63 V, outperforming state‐of‐the‐art Pt/C catalyst‐based device. Moreover, it is shown that Ni‐doped CoO NSs assembled into all‐solid‐state coin cells can power 17 light‐emitting diodes and charge an iPhone 7 mobile phone.
Efficient Triplet–Triplet Annihilation Upconversion in an Electroluminescence Device with a Fluorescent Sensitizer and a Triplet‐Diffusion Singlet‐Blocking Layer
Authors: Chen Chia‐Hsun , Tierce Nathan T. , Leung Man‐kit , Chiu Tien‐Lung , Lin Chi‐Feng , Bardeen Christopher J. , Lee Jiun‐Haw
Published: October 2018

Solid‐state triplet–triplet annihilation upconversion (TTAUC) blue emission in an electroluminescence device (i.e., an organic light‐emitting diode (OLED)) is demonstrated. A conventional green fluorophore, tris‐(8‐hydroxyquinoline)aluminum (Alq3), is employed as the sensitizer that generates 75% triplet under electrical pumping for the blue triplet–triplet annihilation emitter, 9,10‐bis(2′‐naphthyl) anthracene (ADN), with the heterojunction bilayer structure. The operation lifetime is elongated both for ADN blue (4.1x) and Alq3 green (34.8%) emission due to efficient use of excitons and separation of recombination and emission zone. To reduce the singlet quenching (SQ) of blue TTAUC signal by the Alq3 sensitizer with lower bandgap, 1‐(2,5‐dimethyl‐4‐(1‐pyrenyl)phenyl)pyrene (DMPPP) is inserted between the Alq3 and ADN as a triplet‐diffusion‐and‐singlet‐blocking layer. DMPPP exhibits triplet energy close to Alq3 and higher than ADN, as well as higher singlet energy than both Alq3 and ADN. It allows triplet diffusion from Alq3 to ADN, but blocks the SQ of the blue TTAUC signal by Alq3. 86.1% intrinsic efficiency of TTAUC is demonstrated in this trilayer (Alq3/DMPPP/ADN) OLED.
Atomic‐Scale Observation of Electrochemically Reversible Phase Transformations in SnSe2 Single Crystals
Authors: Kim Sungkyu , Yao Zhenpeng , Lim Jin‐Myoung , Hersam Mark C. , Wolverton Chris , Dravid Vinayak P. , He Kai
Published: October 2018

2D materials have shown great promise to advance next‐generation lithium‐ion battery technology. Specifically, tin‐based chalcogenides have attracted widespread attention because lithium insertion can introduce phase transformations via three types of reactions—intercalation, conversion, and alloying—but the corresponding structural changes throughout these processes, and whether they are reversible, are not fully understood. Here, the first real‐time and atomic‐scale observation of reversible phase transformations is reported during the lithiation and delithiation of SnSe2 single crystals, using in situ high‐resolution transmission electron microscopy complemented by first‐principles calculations. Lithiation proceeds sequentially through intercalation, conversion, and alloying reactions (SnSe2 → LixSnSe2 → Li2Se + Sn → Li2Se + Li17Sn4) in a manner that maintains structural and crystallographic integrity, whereas delithiation forms numerous well‐aligned SnSe2 nanodomains via a homogeneous deconversion process, but gradually loses the coherent orientation in subsequent cycling. Furthermore, alloying and dealloying reactions cause dramatic structural reorganization and thereby consequently reduce structural stability and electrochemical cyclability, which implies that deep discharge for Sn chalcogenide electrodes should be avoided. Overall, the findings elucidate atomistic lithiation and delithiation mechanisms in SnSe2 with potential implications for the broader class of 2D metal chalcogenides.
Facile Fabrication of Large‐Area Atomically Thin Membranes by Direct Synthesis of Graphene with Nanoscale Porosity
Authors: Kidambi Piran R. , Nguyen Giang D. , Zhang Sui , Chen Qu , Kong Jing , Warner Jamie , Li An‐Ping , Karnik Rohit
Published: October 2018

Direct synthesis of graphene with well‐defined nanoscale pores over large areas can transform the fabrication of nanoporous atomically thin membranes (NATMs) and greatly enhance their potential for practical applications. However, scalable bottom‐up synthesis of continuous sheets of nanoporous graphene that maintain integrity over large areas has not been demonstrated. Here, it is shown that a simple reduction in temperature during chemical vapor deposition (CVD) on Cu induces in‐situ formation of nanoscale defects (≤2–3 nm) in the graphene lattice, enabling direct and scalable synthesis of nanoporous monolayer graphene. By solution‐casting of hierarchically porous polyether sulfone supports on the as‐grown nanoporous CVD graphene, large‐area (>5 cm2) NATMs for dialysis applications are demonstrated. The synthesized NATMs show size‐selective diffusive transport and effective separation of small molecules and salts from a model protein, with ≈2–100× increase in permeance along with selectivity better than or comparable to state‐of‐the‐art commercially available polymeric dialysis membranes. The membranes constitute the largest fully functional NATMs fabricated via bottom‐up nanopore formation, and can be easily scaled up to larger sizes permitted by CVD synthesis. The results highlight synergistic benefits in blending traditional membrane casting with bottom‐up pore creation during graphene CVD for advancing NATMs toward practical applications.
Charge‐Induced Disorder Controls the Thermal Conductivity of Entropy‐Stabilized Oxides
Authors: Braun Jeffrey L. , Rost Christina M. , Lim Mina , Giri Ashutosh , Olson David H. , Kotsonis George N. , Stan Gheorghe , Brenner Donald W. , Maria Jon‐Paul , Hopkins Patrick E.
Published: October 2018

Manipulating a crystalline material's configurational entropy through the introduction of unique atomic species can produce novel materials with desirable mechanical and electrical properties. From a thermal transport perspective, large differences between elemental properties such as mass and interatomic force can reduce the rate at which phonons carry heat and thus reduce the thermal conductivity. Recent advances in materials synthesis are enabling the fabrication of entropy‐stabilized ceramics, opening the door for understanding the implications of extreme disorder on thermal transport. Measuring the structural, mechanical, and thermal properties of single‐crystal entropy‐stabilized oxides, it is shown that local ionic charge disorder can effectively reduce thermal conductivity without compromising mechanical stiffness. These materials demonstrate similar thermal conductivities to their amorphous counterparts, in agreement with the theoretical minimum limit, resulting in this class of material possessing the highest ratio of elastic modulus to thermal conductivity of any isotropic crystal.
Self‐Assembly of Large‐Area 2D Polycrystalline Transition Metal Carbides for Hydrogen Electrocatalysis
Authors: Zang Xining , Chen Wenshu , Zou Xiaolong , Hohman J. Nathan , Yang Lujie , Li Buxuan , Wei Minsong , Zhu Chenhui , Liang Jiaming , Sanghadasa Mohan , Gu Jiajun , Lin Liwei
Published: October 2018

Low‐dimensional (0/1/2 dimension) transition metal carbides (TMCs) possess intriguing electrical, mechanical, and electrochemical properties, and they serve as convenient supports for transition metal catalysts. Large‐area single‐crystalline 2D TMC sheets are generally prepared by exfoliating MXene sheets from MAX phases. Here, a versatile bottom‐up method is reported for preparing ultrathin TMC sheets (≈10 nm in thickness and >100 μm in lateral size) with metal nanoparticle decoration. A gelatin hydrogel is employed as a scaffold to coordinate metal ions (Mo5+, W6+, Co2+), resulting in ultrathin‐film morphologies of diverse TMC sheets. Carbonization of the scaffold at 600 °C presents a facile route to the corresponding MoCx, WCx, CoCx, and to metal‐rich hybrids (Mo2−xWxC and W/Mo2C–Co). Among these materials, the Mo2C–Co hybrid provides excellent hydrogen evolution reaction (HER) efficiency (Tafel slope of 39 mV dec−1 and 48 mVj = 10 mA cm‐2 in overpotential in 0.5 m H2SO4). Such performance makes Mo2C–Co a viable noble‐metal‐free catalyst for the HER, and is competitive with the standard platinum on carbon support. This template‐assisted, self‐assembling, scalable, and low‐cost manufacturing process presents a new tactic to construct low‐dimensional TMCs with applications in various clean‐energy‐related fields.