bluuebunny/crossref_metadata_2025_split huggingface dataset:
From Groundwork to Efficient Solar Cells: On the Importance of the Substrate Material in Co‐Evaporated Perovskite Solar Cells
Authors: Abzieher Tobias , Feeney Thomas , Schackmar Fabian , Donie Yidenekachew J. , Hossain Ihteaz M. , Schwenzer Jonas A. , Hellmann Tim , Mayer Thomas , Powalla Michael , Paetzold Ulrich W. 
Published: July 2021

AbstractVacuum‐based deposition of optoelectronic thin films has a long‐standing history. However, in the field of perovskite‐based photovoltaics, these techniques are still not as advanced as their solution‐based counterparts. Although high‐efficiency vacuum‐based perovskite solar cells reaching power conversion efficiencies (PCEs) above 20% are reported, the number of studies on the underlying physical and chemical mechanism of the co‐evaporation of lead iodide and methylammonium iodide is low. In this study, the impact of one of the most crucial process parameters in vacuum processes—the substrate material—is studied. It is shown that not only the morphology of the co‐evaporated perovskite thin films is significantly influenced by the surface polarity of the substrate material, but also the incorporation of the organic compound into the perovskite framework. Based on these studies, a selection guide for suitable substrate materials for efficient co‐evaporated perovskite thin films is derived. This selection guide points out that the organic vacuum‐processable hole transport material 2,2″,7,7″‐tetra(N,N‐di‐p‐tolyl)amino‐9,9‐spirobifluorene is an ideal candidate for the fabrication of efficient all‐evaporated perovskite solar cells, demonstrating PCEs above 19%. Furthermore, building on the insights into the formation of the perovskite thin films on different substrate materials, a basic crystallization model for co‐evaporated perovskite thin films is suggested.
Hierarchically Interconnected Piezoceramic Textile with a Balanced Performance in Piezoelectricity, Flexibility, Toughness, and Air Permeability
Authors: Hong Ying , Wang Biao , Long Zhihe , Zhang Zhuomin , Pan Qiqi , Liu Shiyuan , Luo Xiaowei , Yang Zhengbao 
Published: July 2021

AbstractSoftening of piezoelectric materials facilitates the development of flexible wearables and energy harvesting devices. However, as one of the most competitive candidates, piezoelectric ceramic‐polymer composites inevitably exhibit reduced power‐generation capability and weak mechanical strength due to the mismatch of strength and permittivity between the two phases inside. Herein a flexible, air‐permeable, and high‐performance piezoceramic textile composite with a mechanically reinforced hierarchical porous structure is introduced. Based on a template‐assisted sol‐gel method, a three‐order hierarchical ceramic textile is constructed by intertwining submillimeter‐scale multi‐ply ceramic fibers that are further formed by twisting micrometer‐scale one‐ply ceramic fibrils. Theoretical analysis indicates that large mechanical stress can be easily induced in the multi‐order hierarchical structure, which greatly benefits the electrical output. Fabricated samples generate an open‐circuit voltage of 128 V, a short‐circuit current of 120 µA, and an instantaneous power density of 0.75 mW cm−2, much higher than the previously reported works. The developed multi‐order and 3D‐interconnected piezoceramic textile shows satisfactory piezoelectricity (d33 of 190 pm V−1), air permeability (45.1 mm s−1), flexibility (Young's modulus of 0.35 GPa), and toughness (0.125 MJ m−3), collectively. The design strategy of obtaining balanced properties promotes the practicality of smart/functional materials in wearables and flexible electronics.
Electric Field Control of the Magnetic Weyl Fermion in an Epitaxial SrRuO3 (111) Thin Film
Authors: Lin Weinan , Liu Liang , Liu Qing , Li Lei , Shu Xinyu , Li Changjian , Xie Qidong , Jiang Peiheng , Zheng Xuan , Guo Rui , Lim Zhishiuh , Zeng Shengwei , Zhou Guowei , Wang Han , Zhou Jing , Yang Ping , Ariando  , Pennycook Stephen J. , Xu Xiaohong , Zhong Zhicheng , Wang Zhiming , Chen Jingsheng 
Published: July 2021

AbstractThe magnetic Weyl fermion originates from the time reversal symmetry (TRS)‐breaking in magnetic crystalline structures, where the topology and magnetism entangle with each other. Therefore, the magnetic Weyl fermion is expected to be effectively tuned by the magnetic field and electrical field, which holds promise for future topologically protected electronics. However, the electrical field control of the magnetic Weyl fermion has rarely been reported, which is prevented by the limited number of identified magnetic Weyl solids. Here, the electric field control of the magnetic Weyl fermion is demonstrated in an epitaxial SrRuO3 (111) thin film. The magnetic Weyl fermion in the SrRuO3 films is indicated by the chiral anomaly induced magnetotransport, and is verified by the observed Weyl nodes in the electronic structures characterized by the angle‐resolved photoemission spectroscopy (ARPES) and first‐principles calculations. Through the ionic‐liquid gating experiment, the effective manipulation of the Weyl fermion by electric field is demonstrated, in terms of the sign‐change of the ordinary Hall effect, the nonmonotonic tuning of the anomalous Hall effect, and the observation of the linear magnetoresistance under proper gating voltages. The work may stimulate the searching and tuning of Weyl fermions in other magnetic materials, which are promising in energy‐efficient electronics.
Hydrogel Ionic Diodes toward Harvesting Ultralow‐Frequency Mechanical Energy
Authors: Zhang Yong , Jeong Chang Kyu , Wang Jianjun , Chen Xin , Choi Kyoung Hwan , Chen Long‐Qing , Chen Wen , Zhang Q. M. , Wang Qing 
Published: July 2021

AbstractEnergy harvesting from human motion is regarded as a promising protocol for powering portable electronics, biomedical devices, and smart objects of the Internet of things. However, state‐of‐the‐art mechanical‐energy‐harvesting devices generally operate at frequencies (>10 Hz) well beyond human activity frequencies. Here, a hydrogel ionic diode formed by the layered structures of anionic and cationic ionomers in hydrogels is presented. As confirmed by finite element analysis, the underlying mechanism of the hydrogel ionic diode involves the formation of the depletion region by mobile cations and anions and the subsequent increase of the built‐in potential across the depletion region in response to mechanical pressure. Owing to the enhanced ionic rectification ratio by the embedded carbon nanotube and silver nanowire electrodes, the hydrogel ionic diode exhibits a power density of ≈5 mW cm−2 and a charge density of ≈4 mC cm−2 at 0.01 Hz, outperforming the current energy‐harvesting devices by several orders of magnitude. The applications of the self‐powered hydrogel ionic diode to tactile sensing, pressure imaging, and touchpads are demonstrated, with sensing limitation is as low as 0.01 kPa. This work is expected to open up new opportunities for ionic‐current‐based ionotronics in electronics and energy devices.
Multiple Response Colors of Invisible Hollow Silica Photonic Crystals Patterns for Information Encoding
Authors: Xiao Xin , Yang Zhaokun , Yu Qiuyan , Shi Dongjian , Dong Weifu , Zhang Hongji , Chen Mingqing 
Published: July 2021

AbstractCombining responsive and invisible patterns into photonic crystals is an accepted encryption strategy for watermarking and information security. In order to fabricate an invisible pattern with excellent decrypted performance, environmental stability, full reversibility, and multiple responsive color, hollow silica photonic crystals (HSPCs) with selective wettability are fabricated by functional modification and photoinitiated Michael addition reaction. The patterned HSPCs show an identical purple color under a static environment, while they can reveal the hidden image with blue color and green color in response to water vapor flow and ethanol/water solutions, respectively. A large photonic bandgap shift (62 nm) is realized by glycerin wiping due to the large refractive index of glycerin. The prepared invisible PCs patterns show well reversibility in 100 cycles tests and maintain their excellent performances for more than 1 year. Such a multiple response invisible HSPCs patterns can play a crucial role in vapor sensing, information encoding, and anticounterfeiting application.
Visible Light Promoted Chan‐Lam Reaction and Cycloaddition to Prepare Chromeno[4,3‐c]isoxazolidines in One‐Pot Reaction
Authors: Zhao Jie , Huang Bing‐Qing , Zhu Bin‐Can , Ma Xiao‐Pan , Mo Dong‐Liang 
Published: July 2021

AbstractA variety of chromeno[4,3‐c]isoxazolidines were prepared in good yields through visible light promoted Chan‐Lam reaction and [3+2] cycloaddition cascade reaction in one pot. Mechanistic studies showed that visible light promoted both Chan‐Lam reaction and cycloaddition. The obtained products were converted to various useful chromenone derivatives. Moreover, the reaction was easily performed at gram scales with the purification of products without column chromatography and used to efficiently synthesize estrone‐derived chromeno[4,3‐c]isoxazolidine.magnified image
Multiple Longitudinal Polarization Vortices Generated via All‐Silicon Metasurface
Authors: Zheng Chenglong , Li Jie , Li Jitao , Yue Zhen , Zhao Hongliang , Hao Xuanruo , Zhang Yating , Yao Jianquan 
Published: July 2021

AbstractPhotons carry spin angular momentum and orbital angular momentum, vortex beams with helical phase fronts provide a new understanding of optical and physical phenomena. Here, the creation of four longitudinal polarized vortices with arbitrary topological charges is demonstrated using all‐silicon metasurfaces in terahertz band, integrating propagation phase and Pancharatnam–Berry phase. This efficient scheme allows the authors to flexibly control the longitudinal polarized electric field by designing the field distribution of the transverse polarization. As a proof of concept, two metasurfaces are designed to demonstrate the flexibility of such approach. One is used to generate dual longitudinal polarized superpositions of orbital angular momentum states with arbitrary topological charges, and the other is designed to generate four discrete longitudinal vortices. This method may find applications in manipulation of electron bunches and new imaging technology.
Photoresponsive Palladium and Nickel Catalysts for Ethylene Polymerization and Copolymerization
Authors: Peng Dan , Chen Changle 
Published: July 2021

AbstractIn this contribution, we install an azobenzene functionality in olefin polymerization catalysts and use light to modulate their properties via photoinduced trans–cis isomerization of the azobenzene moiety. The initially targeted azobenzene‐functionalized α‐diimine palladium and nickel catalysts are not photoresponsive. To address this issue, an imine–amine system bearing interrupted conjugation with the metal center, and a sandwich‐type α‐diimine system bearing an azobenzene unit at a position covalently far from the metal center were prepared and studied. We demonstrate that light can be used to tune their properties in ethylene polymerization and copolymerization with polar comonomers, enabling light‐induced control of the polymerization processes, polymer microstructures and polymer properties. More interestingly, the light‐mediated property changes were attributed to ligand electronic effects in one system and ligand steric effects in the other.
Carbene‐Stabilized Dithiolene (L0) Zwitterions
Authors: Wang Yuzhong , Tran Phuong M. , Xie Yaoming , Wei Pingrong , Glushka John N. , Schaefer Henry F. , Robinson Gregory H. 
Published: July 2021

AbstractA series of reactions between Lewis bases and an imidazole‐based dithione dimer (1) has been investigated. Both cyclic(alkyl)(amino)carbene (CAAC) (2) and N‐heterocyclic carbene (NHC) (4), in addition to N‐heterocyclic silylene (NHSi) (6), demonstrate the capability to cleave the sulphur–sulphur bonds in 1, giving carbene‐stabilized dithiolene (L0) zwitterions (3 and 5) and a spirocyclic silicon–dithiolene compound (7), respectively. The bonding nature of 3, 5, and 7 are probed by both experimental and theoretical methods.
Facile synthesis of recoverable superparamagnetic AgFeO2@Polypyrrole/SiO2 nanocomposite as an excellent catalyst for reduction and oxidation of different dyes in wastewater
Authors: El‐Attar Heba G. , Salem Mohamed A. , Bakr Eman A. 
Published: July 2021

AbstractFabrication of a triple‐component nanocomposite system having a unique design and unusual property combinations offers a special chance to take advantage of all components and overcome the limitations of mono nanoparticles (NPs). Novel superparamagnetic AgFeO2@polypyrrole/SiO2 (AgFeO2@PPy/SiO2) triple‐component nanocomposite was synthesized in facile three‐step method using (i) coprecipitation, (ii) in situ chemical oxidative polymerization, and (iii) Stöber process. The structure and morphology of the nanocomposite were characterized by Fourier‐transform infrared spectroscopy (FT‐IR), X‐ray powder diffraction (XRD), scanning electron microscopy (SEM), energy‐dispersive X‐ray spectroscopy (EDX), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and vibrating sample magnetometer (VSM). The triple nanocomposite has a drastic catalytic effect as compared with AgFeO2@PPy core–shell NPs and AgFeO2 NPs. The rate constant of chromotrope 2R reduction followed the order: AgFeO2@PPy/SiO2 (0.9209 min−1) > AgFeO2@PPy (0.2274 min−1) > AgFeO2 (0.1365 min−1). AgFeO2@PPy/SiO2 exhibited high catalytic recyclable performance towards the degradation of different kinds of dyes either by reduction (chromotrope 2R, tartrazine, and methylene blue) or by oxidation (methylene blue, aniline blue, and methyl violet 2B) from aqueous solution. The degradation percentage for the reduced dyes was 99.38%, 98.64%, and 98.17% and for the oxidized dyes was 75.84%, 99.34%, and 91.79%, respectively. Batch mode catalytic study was conducted with the nanocomposite to determine the maximum removal of tartrazine and aniline blue under different operational parameters was 99.5% and 99.34%, respectively. The recovery and reusability of the AgFeO2@PPy/SiO2 nanocomposite were studied using the reduction of tartrazine and the oxidation of aniline blue. Thirteen consecutive recovery reaction cycles were performed for the reduction process and nine cycles for the oxidation reaction. All the reactions revealed high stability and constant efficiency of the catalyst. The maximum percentages were 99.5% for the reduction and 99.34% for the oxidation of dyes. These values decreased through the cycles to 76.35% and 79.70% for reduction and oxidation, respectively. Based on the experimental results obtained, the synthesized materials proved to have a high potential for the removal of all investigated dyes from an aqueous solution.
Magnetic porous nano‐carbon catalysts supported silver nanoparticles derived from chitin and their application in catalytic reduction reactions
Authors: Wang Guozhen , Wang Bowen , Chen Xi , Pei Ying , Zhou Shunchao , Ding Wenping 
Published: July 2021

AbstractThe exploitation of recycled carbonaceous catalysts from renewable biomass resources such as chitin is a crucial issue for the development of the sustainable society. In this article, the chitin‐based N and O doped carbon microspheres (ChC) were fabricated by a simple dissolution, sol–gel transformation, and the carbonization methods. Subsequently, the novel magnetic Ag‐Fe3O4@chitin‐based carbon microspheres catalyst (MChC) was successfully constructed through the in situ redox reaction. The as‐prepared MChC possessed rich micropores with high‐surface area, and a narrow size distribution (50–120 μm). The Ag‐Fe3O4 nanoparticles were immobilized through the interaction with C, N, and O atoms in the pores of MChC. The reduction of 4‐nitrophenol was applied to evaluate the catalytic activity of MChC. 4‐Nitrophenol (4‐NP) could be fully reduced to 4‐aminophenol (4‐AP) in 5 min with the catalyst MChC‐45. Moreover, MChC could be collected in solution with an external magnet in 8 s and remained relatively high‐catalytic activity after 10 cycle times. This work provided novel ideas for the fabrication of doped carbon material from biomass and promoted its utilization in nanocatalytic applications.
High‐temperature performance and cross‐linking mechanism of different types of gel systems in saline environment
Authors: Liu Jianbin , Zhong Liguo , Cao Zijuan , Hao Tongchun , Liu Yigang , Wu Wenwei 
Published: July 2021

AbstractProfile modification of injection wells or water plugging of production wells are the most common ways to improve oil recovery with the continuous development of oil reservoirs. For high temperature and high‐salt oil and gas reservoirs, the plugging agent is required to have certain stability under high temperature and high‐salt conditions. Polymer gel is one of the commonly used plugging agents in oil fields. This article conducted detailed experimental research and mechanism analysis on six gel systems composed by two types of polymer (hydrolyzed polyacrylamide [HPAM] and terpolymer L‐1) and three types of cross‐linker systems (phenol/hexamethylenetetramine [HMTA], resorcinol/HMTA and bisphenol‐A/HMTA). The mechanisms of cross‐linker systems and polymer were studied, and the experimental researches were done on their gelation process, long‐term thermal stability, salt resistance, microstructure observation, rheological properties, and so on. The number of high‐temperature resistant cross‐linking points determines the performance of the gel system formed by cross‐linker systems with the polymer. The cross‐linker systems of bisphenol‐A/HMTA have four high‐temperature resistant cross‐linking points, and its performance was the best. Due to the introduction of ATBS and NVP groups on the polymer chain, the performance of gel system formed by the terpolymer L‐1 was significantly more stable than that of formed by HPAM. This study shows that the bisphenol‐A/HMTA‐L‐1 gel has excellent long‐term thermal stability and salt tolerance, and can be used in ultrahigh temperature (150°C) and high‐salt oil and gas reservoirs to improve oil recovery.
The C‐terminally shortened analogs of a hexapeptide derived from Lingzhi hydrolysate with enhanced tyrosinase‐inhibitory activity
Authors: Krobthong Sucheewin , Yingchutrakul Yodying , Samutrtai Pawitrabhorn , Choowongkomon Kiattawee 
Published: July 2021

AbstractGanoderma lucidum or Lingzhi (Chinese) is a medicinal fungus widely used in traditional medicine as a health supplement. This study was conducted to identify an approach to enhance the anti‐tyrosinase activity of a peptide from G. lucidum by chemical modification of its C‐terminus. The original peptide was obtained from protease‐digested Lingzhi proteins, followed by ultrafiltration (molecular weight cut‐off 3 kDa) and C18 solid‐phase extraction. The hexapeptide (NH2–VLTCGF–COOH) possessing the anti‐tyrosinase activity was identified by liquid chromatography–tandem mass spectrometry (LC‐MS/MS). This hexapeptide was subjected to shortening to enhance the anti‐tyrosinase activity. Both the original peptide and the shortened peptides were synthesized by solid‐phase peptide synthesis. The purity and mass of the synthetic peptide and the modified peptide were evaluated by high‐performance liquid chromatography and LC‐MS, respectively. Comparison of the tyrosinase activities showed that the modified peptide demonstrated more than 23.27 ± 1.07% activity, which was better than that of the hexapeptide. The structure‐related biological activity was explained by molecular docking, wherein the VLT–tyrosinase complex showed two interaction forces: Asn260 and Gly281 through H‐bonding and Glu256 through electrostatic interaction. This information could help toward gaining further understanding of the correlation between the anti‐tyrosinase activity and the molecular structure of the modified hexapeptide and support its potential use as a safe cosmetic ingredient with tyrosinase‐suppressing ability.
Global efficiency of the motor network is decreased in Parkinson's disease in comparison with essential tremor and healthy controls
Authors: Novaes Natalia Pelizari , Balardin Joana Bisol , Hirata Fabiana Campos , Melo Luciano , Amaro Edson , Barbosa Egberto Reis , Sato João Ricardo , Cardoso Ellison Fernando 
Published: July 2021

AbstractBackgroundGraph theory (GT) is a mathematical field that analyses complex networks that can be applied to neuroimaging to quantify brain's functional systems in Parkinson's disease (PD) and essential tremor (ET).ObjectivesTo evaluate the functional connectivity (FC) measured by the global efficiency (GE) of the motor network in PD and compare it to ET and healthy controls (HC), and correlate it to clinical parameters.Methods103 subjects (54PD, 18ET, 31HC) were submitted to structural and functional MRI. A network was designed with regions of interest (ROIs) involved in motor function, and GT was applied to determine its GE. Clinical parameters were analyzed as covariates to estimate the impact of disease severity and medication on GE.ResultsGE of the motor circuit was reduced in PD in comparison with HC (p .042). Areas that most contributed to it were left supplementary motor area (SMA) and bilateral postcentral gyrus. Tremor scores correlated positively with GE of the motor network in PD subgroups. For ET, there was an increase in the connectivity of the anterior cerebellar network to the other ROIs of the motor circuit in comparison with PD.ConclusionsFC measured by the GE of the motor network is diminished in PD in comparison with HC, especially due to decreased connectivity of left SMA and bilateral postcentral gyrus. This finding supports the theory that there is a global impairment of the motor network in PD, and it does not affect just the basal ganglia, but also areas associated with movement modulation. The ET group presented an increased connectivity of the anterior cerebellar network to the other ROIs of the motor circuit when compared to PD, which reinforces what it is known about its role in this pathology.