bluuebunny/crossref_metadata_2025_split huggingface dataset:
Understanding the Critical Role of Binders in Phosphorus/Carbon Anode for Sodium‐Ion Batteries through Unexpected Mechanism
Authors: Xiao Wei , Sun Qian , Banis Mohammad Norouzi , Wang Biqiong , Li Weihan , Li Minsi , Lushington Andrew , Li Ruying , Li Xifei , Sham Tsun‐Kong , Sun Xueliang 
Published: June 2020

AbstractPolymer binders that combine active materials with conductive agents have played a critical role in maintaining the structural integrity of phosphorus anodes with a huge volume change upon sodiation/desodiation. Herein, the role of binders on the structural/chemical stability of phosphorus/carbon anode is spectroscopically uncovered through unexpected mechanism. Surprisingly, the selection of different binders is found to determine the oxidation degree of active phosphorus in various electrodes, which correlate well with their electrochemical properties. At a high oxidation degree, the electrode applying a conventional poly(vinylidene difluoride) binder displays the worst electrochemical properties, while the electrode using a sodium alginate binder delivers the best electrochemical performance (a highly reversible capacity of 1064 mAh g−1 with a 90.1% capacity retention at 800 mA g−1 after 200 cycles and an outstanding rate capability of 401 mAh g−1 at 8000 mA g−1) for its negligible oxidation. Additionally, the emergence/decomposition of surface intermediates, including (PO2)3− and (PO4)3− species, are observed in the discharging/charging processes via the ex situ P K‐edge X‐ray absorption spectroscopies. This novel discovery of the unique role of binders in phosphorus anodes, not only provides an opportunity to ameliorate their electrochemical properties, but also enables their practical applications in high‐energy sodium‐ion batteries.
A “Trojan Horse” Camouflage Strategy for High‐Performance Cellulose Paper and Separators
Authors: Zhang Fang , Lan Xiwei , Peng Huawen , Hu Xianluo , Zhao Qiang 
Published: June 2020

AbstractLignin‐carbohydrate complexes (LCC) underpin the comprehensive properties of natural wood. Facile restoration of LCC analogues in paper is challenging because of the charge repulsion between negatively charged lignin and pulp fibrils. A camouflage strategy is discovered to prepare positively charged lignosulfonate–polyamide‐epichlorohydrin complex (LPC) nanoparticles, which are effectively incorporated in pulp through the “LPC–pulp” attraction instead of “lignosulfonate–pulp” repulsion. Water‐resistant LPC paper sheets are prepared in ≈20 min without pressurization. They exhibit high tensile strength (41 MPa), surviving boiling water treatment for 14 days, on par with the strength of pristine paper and certain plastics in a dry state. The camouflage strategy applies to various pulps and processing technologies, as exemplified by a paper separator showing exceptional electrolyte wettability and rate capability in lithium‐ion batteries. This work establishes advanced cellulose valorization with combined strength, water stability, and tailored microstructures replacing petroleum polymers in engineering and energy implications.
Energy Level Engineering in Organic Thin Films by Tailored Halogenation
Authors: Ortstein Katrin , Hutsch Sebastian , Hinderhofer Alexander , Vahland Jörn , Schwarze Martin , Schellhammer Sebastian , Hodas Martin , Geiger Thomas , Kleemann Hans , Bettinger Holger F. , Schreiber Frank , Ortmann Frank , Leo Karl 
Published: June 2020

AbstractIn modern electronics, it is essential to adapt band structures by adjusting energy levels and band gaps. At first sight, this “band structure engineering” seems impossible in organic semiconductors, which usually exhibit localized electronic states instead of Bloch bands. However, the strong Coulomb interaction in organic semiconductors allows for a continuous shift of the ionization energy (IE) over a wide range by mixing molecules with halogenated derivatives that exhibit different quadrupole moments. Here, this effect of energy level engineering on blends of pentacene and two fluorinated derivatives, in which the position but not the number of fluorine atoms differ, is studied. Structural investigations confirm that pentacene forms intermixed phases in blends with the fluorinated species. The investigation of electronic properties and simulations reveals a much larger shift of the ionization energy (1.5 eV) than in previous studies, allowing to test this model in a range not investigated so far, and emphasizing the role of the position of the halogen atoms. The tuning effect is preserved in electronic devices such as field‐effect transistors and significantly influences device characteristics.
Anion Substitution in Porous Aromatic Frameworks: Boosting Molecular Permeability and Selectivity for Membrane Acetylene Separation
Authors: Zhang Panpan , Zou Xiaoqin , Song Jian , Tian Yuyang , Zhu Youliang , Yu Guangli , Yuan Ye , Zhu Guangshan 
Published: June 2020

AbstractPrecise tailoring of pore chemistry is indispensable for efficient membrane gas separation, particularly for the challenging acetylene system. Here, a strategy called “anion substitution” is reported, to strengthen the interaction between anions and acetylene within the pores, for radically improving gas selectivity and permeability. The anions F−and OH−are infixed in iPAF‐1 to replace the original Cl−ion. Their small anionic radii allow retention of the original high porosity of iPAF‐1‐Cl in iPAF‐1‐F and iPAF‐1‐OH. Highly basic F−and OH−confined in the pores attract acidic acetylene strongly and preferentially. Nanoparticles of iPAF‐1 are processed to form mixed matrix membranes, represented by iPAF‐1‐OH/6FDA‐ODA. The prepared membranes exhibit remarkable performance in separating acetylene from ethylene and ethane. Transplantation of porous and functional iPAF‐1‐OH into 6FDA‐ODA significantly enhances both acetylene permeability (sevenfold) and permselectivity (fivefold) for acetylene over ethylene and ethane, which is crucial for membrane acetylene gas separation.
Hofmeister‐Effect‐Guided Ionohydrogel Design as Printable Bioelectronic Devices
Authors: Shang Yinghui , Wu Chu , Hang Chengzhou , Lu Hongliang , Wang Qigang 
Published: June 2020

AbstractBioelectronic platforms convert biological signals into electrical signals by utilizing biocatalysts that provide tools to monitor the activity of cells and tissues. Traditional conducting materials such as solid conductors and conducting polymers are confronted with a great challenge in sophisticated production processes and mismatch at biological tissues–machine interfaces. Furthermore, the biocatalyst, the key functional component in the electron‐transfer reaction for bio‐signal detection denatures easily in an ionic conductive solution. Herein, a bionic strategy is elaborately developed to synthesize an ionohydrogel bioelectronic platform that possesses extracellular‐matrix‐like habitat by employing hydrated ionic liquids (HILs) as ionic solvent and bioprotectant. This strategy realizes an integration of ionic and enzymatic electronic circuits and minimization of the disparities between tissues and artificial machines. The Hofmeister effect of HILs on enzyme proteins and polymer chains ensures the high bioactivity of the enzymes and greatly improves the mechanical properties of the ionohydrogels. Moreover, hydrogen bonds formed by ILs, water, and polymer chains greatly improve the water‐retention of the ionohydrogel and give it more practical significance. Consequently, the promising ionohydrogel is partly printed and fabricated into wearable devices as a pain‐free humoral components monitor and a wireless motion‐sensor.
Cs4PbI6‐Mediated Synthesis of Thermodynamically Stable FA0.15Cs0.85PbI3 Perovskite Solar Cells
Authors: Shao Zhipeng , Meng Hongguang , Du Xiaofan , Sun Xiuhong , Lv Peiliang , Gao Caiyun , Rao Yi , Chen Chen , Li Zhipeng , Wang Xiao , Cui Guanglei , Pang Shuping 
Published: June 2020

AbstractThe stability issue is still one of the main limitations of the commercialization of perovskite photovoltaics. The mixed cation FAxCs1−xPbI3 has shown great promise owing to its improved thermal and moisture stability. However, the study of FAxCs1−xPbI3 is concentrated on formamidine (FA)‐rich perovskite, whereas cesium (Cs)‐rich FAxCs1−xPbI3 perovskites are barely studied due to the inevitable phase separation when Cs > 30 mol%. Here, a Cs4PbI6‐mediated method is developed to synthesize Cs‐rich FAxCs1−xPbI3 perovskites. It is demonstrated that Cs4PbI6 intermediate phase has a low Cs cation diffusion barrier and therefore offers a fast ion exchange with the preformed FA‐rich perovskite phase to finally form the Cs‐rich FAxCs1−xPbI3 perovskite. The results indicate that ≈15% alloying with organic FA cations can sufficiently stabilize the perovskite phase with excellent phase and UV‐irradiation stability. The FA0.15Cs0.85PbI3 perovskite solar cells achieve a champion power conversion efficiency of 17.5%, showing the great potential of Cs‐based perovskites for efficient and stable solar cells.
Quantum Confinement of Dirac Quasiparticles in Graphene Patterned with Sub‐Nanometer Precision
Authors: Cortés‐del Río Eva , Mallet Pierre , González‐Herrero Héctor , Lado José Luis , Fernández‐Rossier Joaquín , Gómez‐Rodríguez José María , Veuillen Jean‐Yves , Brihuega Iván 
Published: June 2020

AbstractQuantum confinement of graphene Dirac‐like electrons in artificially crafted nanometer structures is a long sought goal that would provide a strategy to selectively tune the electronic properties of graphene, including bandgap opening or quantization of energy levels. However, creating confining structures with nanometer precision in shape, size, and location remains an experimental challenge, both for top‐down and bottom‐up approaches. Moreover, Klein tunneling, offering an escape route to graphene electrons, limits the efficiency of electrostatic confinement. Here, a scanning tunneling microscope (STM) is used to create graphene nanopatterns, with sub‐nanometer precision, by the collective manipulation of a large number of H atoms. Individual graphene nanostructures are built at selected locations, with predetermined orientations and shapes, and with dimensions going all the way from 2 nm up to 1 µm. The method permits the patterns to be erased and rebuilt at will, and it can be implemented on different graphene substrates. STM experiments demonstrate that such graphene nanostructures confine very efficiently graphene Dirac quasiparticles, both in 0D and 1D structures. In graphene quantum dots, perfectly defined energy bandgaps up to 0.8 eV are found that scale as the inverse of the dot’s linear dimension, as expected for massless Dirac fermions.
Conversion of Intercalated MoO3 to Multi‐Heteroatoms‐Doped MoS2 with High Hydrogen Evolution Activity
Authors: Yang Weiwei , Zhang Shuqing , Chen Qian , Zhang Chao , Wei Yi , Jiang Huaning , Lin Yunxiang , Zhao Mengting , He Qianqian , Wang Xingguo , Du Yi , Song Li , Yang Shubin , Nie Anmin , Zou Xiaolong , Gong Yongji 
Published: June 2020

AbstractLack of effective strategies to regulate the internal activity of MoS2 limits its practical application for hydrogen evolution reactions (HERs). Doping of heteroatoms without forming aggregation or an edge enrichment is still challenging, and its effect on the HER needs to be further explored. Herein, a two‐step method is developed to obtain multi‐metal‐doped H‐MoS2, which includes intercalation of the layered MoO3 precursor with a following sulfurization. Benefiting from the capability of the intercalation method to uniformly and simultaneously introduce different elements into the van der Waals gap, this method is universal to obtain multi‐heteroatoms co‐doped MoS2 without forming clusters, phase separation, and an edge enrichment. It is demonstrated that the doping of adjacent cobalt and palladium monomers on MoS2 greatly enhances the HER catalytic activity. The overpotential at 10 mA cm−2 and Tafel slope of Co and Pd co‐doped MoS2 is found to be 49.3 mV and 43.2 mV dec−1, respectively, representing a superior acidic HER catalytic activity. This intercalation‐assisted method also provides a new and general strategy to synthesize uniformly doped transition metal dichalcogenides for various applications.
Directed Assembly of Liquid Metal–Elastomer Conductors for Stretchable and Self‐Healing Electronics
Authors: Krisnadi Febby , Nguyen Linh Lan , Ankit  , Ma Jinwoo , Kulkarni Mohit Rameshchandra , Mathews Nripan , Dickey Michael D. 
Published: June 2020

AbstractGrowing interest in soft robotics, stretchable electronics, and electronic skins has created demand for soft, compliant, and stretchable electrodes and interconnects. Here, dielectrophoresis (DEP) is used to assemble, align, and sinter eutectic gallium indium (EGaIn) microdroplets in uncured poly(dimethylsiloxane) (PDMS) to form electrically conducting microwires. There are several noteworthy aspects of this approach. 1) Generally, EGaIn droplets in silicone at loadings approaching 90 wt% remain insulating and form a conductive network only when subjected to sintering. Here, DEP facilitates assembly of EGaIn droplets into conductive microwires at loadings as low as 10 wt%. 2) DEP is done in silicone for the first time, enabling the microwires to be cured in a stretchable matrix. 3) Liquid EGaIn droplets sinter during DEP to form a stretchable metallic microwire that retains its shape after curing the silicone. 4) Use of liquid metal eliminates the issue of compliance mismatch observed in soft polymers with solid fillers. 5) The silicone–EGaIn “ink” can be assembled by DEP within the crevices of severely damaged wires to create stretchable interconnects that heal the damage mechanically and electrically. The DEP process of this unique set of materials is characterized and the interesting attributes enabled by such liquid microwires are demonstrated.
Multiply Charged Conjugated Polyelectrolytes as a Multifunctional Interlayer for Efficient and Scalable Perovskite Solar Cells
Authors: Jung Eui Dae , Harit Amit Kumar , Kim Do Hui , Jang Chung Hyeon , Park Jong Hyun , Cho Shinuk , Song Myoung Hoon , Woo Han Young 
Published: June 2020

AbstractA series of anionic conjugated polyelectrolytes (CPEs) is synthesized based on poly(fluorene‐co‐phenylene) by varying the side‐chain ionic density from two to six per repeat units (MPS2‐TMA, MPS4‐TMA, and MPS6‐TMA). The effect of MPS2, 4, 6‐TMA as interlayers on top of a hole‐extraction layer of poly(bis(4‐phenyl)‐2,4,6‐trimethylphenylamine (PTAA) is investigated in inverted perovskite solar cells (PeSCs). Owing to the improved wettability of perovskites on hydrophobic PTAA with the CPEs, the PeSCs with CPE interlayers demonstrate a significantly enhanced device performance, with negligible device‐to‐device dependence relative to the reference PeSC without CPEs. By increasing the ionic density in the MPS‐TMA interlayers, the wetting, interfacial defect passivation, and crystal growth of the perovskites are significantly improved without increasing the series resistance of the PeSCs. In particular, the open‐circuit voltage increases from 1.06 V for the PeSC with MPS2‐TMA to 1.11 V for the PeSC with MPS6‐TMA. The trap densities of the PeSCs with MPS2,4,6‐TMA are further analyzed using frequency‐dependent capacitance measurements. Finally, a large‐area (1 cm2) PeSC is successfully fabricated with MPS6‐TMA, showing a power conversion efficiency of 18.38% with negligible hysteresis and a stable power output under light soaking for 60 s.
Chiral Assemblies of Laser‐Printed Micropillars Directed by Asymmetrical Capillary Force
Authors: Hu Yanlei , Yuan Hongwei , Liu Shunli , Ni Jincheng , Lao Zhaoxin , Xin Chen , Pan Deng , Zhang Yiyuan , Zhu Wulin , Li Jiawen , Wu Dong , Chu Jiaru 
Published: June 2020

AbstractArtificial microstructures composed of chiral building blocks are of great significance in the fields of optics and mechanics. Here, it is shown that highly ordered chiral structures can be spontaneously assembled by a meniscus‐directed capillary force arising in an evaporating liquid. The chirality is facilitated by rationally breaking the intrinsic symmetry in the unit cells through cooperative control of the geometry and spatial topology of the micropillars. The interfacial dynamics of the assembly process are studied to show that the sequential self‐organization of the micropillars is influenced by the geometries, stiffness, and spatial arrangements. A diversity of chiral assemblies with controlled handedness is yielded by varying the pillar number, height, cross‐section, laser power, and spatial topology. Lastly, the differential reflectance of light carrying opposite orbital angular momentums on the assembled chiral architectures are investigated, showcasing their potential in the field of chiral photonics concerning enantioselective response and exceptional optical functions.
Soft Electronics for the Skin: From Health Monitors to Human–Machine Interfaces
Authors: Rao Zhoulyu , Ershad Faheem , Almasri Abdullah , Gonzalez Lei , Wu Xiaoyang , Yu Cunjiang 
Published: June 2020

AbstractConventional bulky and rigid electronics prevent compliant interfacing with soft human skin for health monitoring and human–machine interaction, due to the incompatible mechanical characteristics. To overcome the limitations, soft skin‐mountable electronics with superior mechanical softness, flexibility, and stretchability provide an effective platform for intimate interaction with humans. In addition, soft electronics offer comfortability when worn on the soft, curvilinear, and dynamic human skin. Herein, recent advances in soft electronics as health monitors and human–machine interfaces (HMIs) are briefly discussed. Strategies to achieve softness in soft electronics including structural designs, material innovations, and approaches to optimize the interface between human skin and soft electronics are briefly reviewed. Characteristics and performances of soft electronic devices for health monitoring, including temperature sensors, pressure sensors for pulse monitoring, pulse oximeters, electrophysiological sensors, and sweat sensors, exemplify their wide range of utility. Furthermore, the soft electronic devices for prosthetic limb, household object, mobile machine, and virtual object control are presented to highlight the current and potential implementations of soft electronics for a broad range of HMI applications. Finally, the current limitations and future opportunities of soft skin‐mountable electronics are also discussed.
A Gel‐Free Ti3C2Tx‐Based Electrode Array for High‐Density, High‐Resolution Surface Electromyography
Authors: Murphy Brendan B. , Mulcahey Patrick J. , Driscoll Nicolette , Richardson Andrew G. , Robbins Gregory T. , Apollo Nicholas V. , Maleski Kathleen , Lucas Timothy H. , Gogotsi Yury , Dillingham Timothy , Vitale Flavia 
Published: June 2020

AbstractWearable sensors for surface electromyography (EMG) are composed of single‐ to few‐channel large‐area contacts, which exhibit high interfacial impedance and require conductive gels or adhesives to record high‐fidelity signals. These devices are also limited in their ability to record activation across large muscle groups due to poor spatial coverage. To address these challenges, a novel high‐density EMG array is developed based on titanium carbide (Ti3C2Tx) MXene encapsulated in parylene‐C. Ti3C2Tx is a 2D nanomaterial with excellent electrical, electrochemical, and mechanical properties, which forms colloidally stable aqueous dispersions, enabling safe, scalable solutions‐processing. Leveraging the excellent combination of metallic conductivity, high pseudocapacitance, and ease of processability of Ti3C2Tx MXene, the fabrication of gel‐free, high‐density EMG arrays is demonstrated, which are ≈8 µm thick, feature 16 recording channels, and are highly skin conformable. The impedance of Ti3C2Tx electrodes in contact with human skin is 100–1000× lower than the impedance of commercially available electrodes which require conductive gels to be effective. Furthermore, the arrays can record high‐fidelity, low‐noise EMG, and can resolve muscle activation with improved spatiotemporal resolution and sensitivity compared to conventional gelled electrodes. Overall, the results establish Ti3C2Tx‐based bioelectronic interfaces as a powerful platform technology for high‐resolution, noninvasive wearable sensing technologies.
Boosting Efficiency of Near‐Infrared Emitting Iridium(III) Phosphors by Administrating Their π–π Conjugation Effect of Core–Shell Structure in Solution‐Processed OLEDs
Authors: You Caifa , Liu Denghui , Yu Junting , Tan Hua , Zhu Mengbing , Zhang Bin , Liu Yu , Wang Yafei , Zhu Weiguo 
Published: June 2020

AbstractHigh‐efficiency near‐infrared (NIR) phosphorescent emitter is still a great challenge in solution processable organic light‐emitting diodes (OLEDs). Herein, four novel NIR‐emitting iridium(III) complexes with core–shell structure, named as Ir1, Ir2, Ir3, and Ir4, are rationally designed and synthesized, in which the highly rigid dibenzo[a,c] phenazine (DBPz) moiety is used as coordinated core and the flexible hexyl‐thienyl or 4‐(N,N‐diphenylamino)phenyl as peripheral shell anchored in 3, 6‐, or 11, 12‐positions of DBPz. The influence of the core–shell structure on molecular aggregation, photophysical properties, and electroluminescent (EL) performance is systematically investigated. It is found that core–shell structure and substituted positions of shells have great influences on properties of iridium(III) complexes. Intense NIR emissions at 710–740 nm are observed with luminescent quantum yields of 18–30% in these complexes. Solution‐processed NIR‐OLEDs based on Ir3 or Ir4 show better electroluminescent properties. The maximum external quantum efficiency of 13.72% with a radiance of 26 996 mW Sr−1 m−2 (@708 nm) is obtained in Ir3‐doped OLEDs, representing the state‐of‐the‐art EL performance in the iridium complex‐based NIR‐OLEDs. This work demonstrates that administrating π–π conjugation effects of core–shell structure in C^N ligand is a new avenue to obtain high‐efficiency NIR‐emitting iridium(III) complexes.
Reversible On–Off of Chirality and Anisotropy in Patterned Coexistence of Achiral‐Anisotropic and Chiral‐Isotropic Soft Materials
Authors: Mo Qinyu , Liu Binghui , Huang Wenbin , Sun Pei‐Zhi , Li Zhiying , Bisoyi Hari Krishna , Shen Dong , Zheng Zhi‐Gang , Lu Yan‐Qing , Li Quan 
Published: June 2020

AbstractAchieving a coexistence of two or multiple phases of soft matters via a delicate trade‐off of free energy and long‐range order with one another has been inspiring abundant interest on fundamental sciences and engineering. In this work, a stable coexistence of the optically achiral‐anisotropic liquid crystalline nematic phase and the optically chiral‐isotropic liquid crystalline blue phase is proposed and demonstrated, with their distribution tailored in a micro‐pattern by the developed localized micro‐regional polymer templating technique. Such a stable patterned coexistence of the two different phases with a distinct molecular arrangement, optical chirality, and anisotropy is achieved depending on a delicate matching of the elastic energy on the interface between liquid crystals and polymer networks. In contrast to the majority of soft coexistence systems, a specific dynamic and reversible on–off response of chirality and anisotropy is observed in such a system driven by an electric field. The structure of patterned coexistence system in the presence and absence of external stimulation is explored by microscopy and optical technique, and furthermore, the prospective photonic applications are demonstrated. This investigation indicates another category of functional soft material with fantastic adaptive characteristics for application in optics, electronics, interface physics, and chemistry.