bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electron Trap Dynamics in Polymer Light‐Emitting Diodes
Authors: Diethelm Matthias , Bauer Michael , Hu Wei‐Hsu , Vael Camilla , Jenatsch Sandra , Blom Paul W. M. , Nüesch Frank , Hany Roland 
Published: April 2022

AbstractSemiconducting polymers are being studied intensively for optoelectronic device applications, including solution‐processed light‐emitting diodes (PLEDs). Charge traps in polymers limit the charge transport and thus the PLED efficiency. It is firmly established that electron transport is hindered by the presence of the universal electron trap density, whereas hole trap formation governs the long‐term degradation of PLEDs. Here, the response of PLEDs to electrical driving and breaks covering the timescale from microseconds to (a few) hours is studied, thus focusing on electron traps. As reference polymer, a phenyl‐substituted poly(para‐phenylene vinylene) (PPV) copolymer termed super yellow (SY) is used. Three different traps with depths between ≈0.4 and 0.7 eV, and a total trap site density of ≈2 × 1017 cm−3 are identified. Surprisingly, filling of deep traps takes minutes to hours, at odds with the common notion that charge trapping is complete after a few hundred microseconds. The slow trap filling feature for PLEDs is confirmed using poly(2‐methoxy‐5‐(2‐ethylhexyloxy)‐1,4‐phenylene vinylene (MEH‐PPV) and poly(3‐hexylthiophene) (P3HT) as active materials. This unusual phenomenon is explained with trap deactivation upon detrapping and slow trap reactivation. The results provide useful insight to pinpoint the chemical nature of the universal electron traps in semiconducting polymers.
The Role of SnF2 Additive on Interface Formation in All Lead‐Free FASnI3 Perovskite Solar Cells
Authors: Zillner Julia , Boyen Hans‐Gerd , Schulz Philip , Hanisch Jonas , Gauquelin Nicolas , Verbeeck Johan , Küffner Johannes , Desta Derese , Eisele Lisa , Ahlswede Erik , Powalla Michael 
Published: April 2022

AbstractTin‐based perovskites are promising alternative absorber materials for lead‐free perovskite solar cells but need strategies to avoid fast tin (Sn) oxidation. Generally, this reaction can be slowed down by the addition of tin fluoride (SnF2) to the perovskite precursor solution, which also improves the perovskite layer morphology. Here, this work analyzes the spatial distribution of the additive within formamidinium tin triiodide (FASnI3) films deposited on top of poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) hole transporting layers. Employing time‐of‐flight secondary ion mass spectrometry and a combination of hard and soft X‐ray photoelectron spectroscopy, it is found that SnF2 preferably accumulates at the PEDOT:PSS/perovskite interface, accompanied by the formation of an ultrathin SnS interlayer with an effective thickness of ≈1.2 nm.
A Sustainable Self‐Induced Solution Seeding Approach for Multipurpose BiFeO3 Active Layers in Flexible Electronic Devices
Authors: Barrios Óscar , Jiménez Ricardo , Ricote Jesús , Tartaj Pedro , Calzada María Lourdes , Bretos Íñigo 
Published: April 2022

AbstractThe direct integration of crystalline oxide layers into flexible electronic systems requires the development of relatively simple, low‐temperature processing routes. Seeding represents a powerful strategy to reach this objective by the generation of preferential sites for the nucleation of crystalline phases with a reduced energy barrier. Here, a novel approach is reported where nanoseeds are generated in situ from a precursor solution using a solvent‐engineering strategy (solvent‐antisolvent). The controlled addition of an antisolvent (1,3‐propanediol) to a solution of metal salts (Bi/Fe) dissolved in acetic acid results in the formation of nanocrystals (seeds) by supersaturation. The presence of such nanoseeds is also confirmed in the deposited layers, improving significantly the crystallinity of the respective BiFeO3 thin films as complementary, deduced by piezoresponse force microscopy. Using this low‐temperature strategy, crystalline films are directly grown on flexible polymeric substrates at only 350 °C showing a remanent polarization of 10.5 µC cm−2 and a clear photovoltaic effect (11.7 µW cm−2) of interest in computer memories and energy harvesters. The flexibility of the BiFeO3 thin films may enlarge the number of applications of this multifunctional, lead‐free material in next‐generation digital and sustainable electronic devices based on a facile, low‐cost fabrication method with reduced energy consumption.
Silica‐Coated Gold Nanorod Supraparticles: A Tunable Platform for Surface Enhanced Raman Spectroscopy
Authors: van der Hoeven Jessi E.S. , Gurunarayanan Harith , Bransen Maarten , de Winter D.A. Matthijs , de Jongh Petra E. , van Blaaderen Alfons 
Published: April 2022

AbstractPlasmonic nanoparticle assemblies are promising functional materials for surface‐enhanced Raman spectroscopy (SERS). Gold nanorod (AuNR) assemblies are of particular interest due to the large, shape‐induced local field enhancement and the tunable surface plasmon resonance of the AuNRs. Designing the optimal assembly structure for SERS, however, is challenging and requires a delicate balance between the interparticle distance, porosity, and wetting of the assembly. Here, a new type of functional assemblies–called supraparticles–fabricated through the solvent‐evaporation driven assembly of silica‐coated gold nanorods into spherical ensembles, in which the plasmonic coupling and the mass transport is tuned through the thickness and porosity of the silica shells are introduced. Etching of the AuNRs allowed fine‐tuning of the plasmonic response to the laser excitation wavelength. Using a correlative SERS‐electron microscopy approach, it is shown that all supraparticles successfully amplified the Raman signal of the crystal violet probe molecules, and that the Raman signal strongly increased when decreasing the silica shell thickness from 35 to 3 nm, provided that the supraparticles have a sufficiently high porosity. The supraparticles introduced in this study present a novel class of materials for sensing, and open up a wide parameter space to optimize their performance.
Engineering Densely Packed Adipose Tissue via Environmentally Controlled In‐Bath 3D Bioprinting
Authors: Ahn Minjun , Cho Won‐Woo , Kim Byoung Soo , Cho Dong‐Woo 
Published: April 2022

AbstractThe adipose tissue is a crucial endocrine organ that coordinates with other organs, playing a key role in metabolic regulation. However, it remains challenging to recreate the morphology of native adipose tissue with fully packed adipogenic lipid droplets, mainly because of immature adipogenesis caused by the low cell density of current adipose constructs. This study suggests environmentally controlled in‐bath 3D bioprinting to create fully‐mature densely packed adipose tissue (DPAT) in vitro. As a bath suspension, a hybrid bioink composed of 1% alginate and 1.5% adipose‐derived decellularized matrix is developed for selective and compact cell proliferation. In the hybrid bath suspension, the construct printed at a high cell density (>107 cells ml−1) proliferates within the predefined area without unwanted cell migration throughout the bath suspension, forming a densely packed cellular microenvironment. After adipogenesis for 4 weeks, the results demonstrate that selectively proliferated preadipocytes can differentiate into lipid‐accumulating mature adipocytes. The resulting in vivo‐like DPAT is successfully engineered in vitro. The DPAT construct shows the physiological changes associated with obesity under the relevant conditions found in obese patients. The recapitulation of obesity‐induced inflamed adipose tissue through co‐culture with monocytes reveals the potency of the proposed strategy as a promising solution to overcome obesity‐related complications.
Toward Direct Growth of Ultra‐Flat Graphene
Authors: Jiang Bei , Liang Dongdong , Sun Zhongti , Ci Haina , Liu Bingzhi , Gao Yaqi , Shan Jingyuan , Yang Xiaoqin , Rümmeli Mark H. , Wang Junxi , Wei Tongbo , Sun Jingyu , Liu Zhongfan 
Published: April 2022

AbstractThe elimination of wrinkles has become a research hotspot in the realm of the chemical vapor deposition growth of graphene, and there have been reliable routes developed for the scenario of catalytic synthesis on metals. Nonetheless, the transfer‐free growth of graphene over insulating substrates affording ultra‐flatness remains a puzzle. Here, the authors report the direct preparation of ultra‐flat graphene on an economical quartz glass substrate at a wafer level, without any wrinkles and metallic impurities, is reported. Density functional theory calculations are employed to establish that graphene adlayer is prone to generate in the presence of textured particulates. In parallel, a critical temperature regime (1443–1453 K), is identified within which graphene adlayer‐restrained forming and substrate in‐situ flattening could simultaneously occur. The thus‐obtained graphene enables the atomically smooth growth of a GaN film with (001) single‐crystallinity over the amorphous substrate. This technique is particularly attractive in the context of cost‐effective integration of emerging III‐nitrides toward exciting applications.
Manipulating Polymer Configuration to Accelerate Cation Intercalation Kinetics for High‐Performance Aqueous Zinc‐Ion Batteries
Authors: Wang Xinlei , Tang Jian , Tang Weihua 
Published: April 2022

AbstractAqueous zinc‐ion batteries (ZIBs) with safety and cost superiority are becoming promising for energy storage; meanwhile, organic electrodes are attracting considerable interest. The development of organic ZIBs lies in the solution of challenging issues on impeded Zn2+ interfacial diffusion and the corresponding sluggish reaction kinetics. Herein, triquinoxalinylene (3Q) based homopolymer (P3Q) and triazine‐linked 3Q polymer (P3Q‐t) with enlarged conjugated planes are designed and prepared to reveal the impact of molecular configuration on Zn2+ transfer and coordination dynamics. Their ZIB performance and ion intercalation mechanism are systematically investigated by structural characterization, electrochemical measurement, and theoretical calculation. Specifically, P3Q shows interactions with both Zn2+ and H+, while P3Q‐t is discovered to selectively coordinate only with Zn2+. Moreover, P3Q‐t exhibits high conjugated planarity and electronegative fused‐rings pathways due to both intermolecular and intramolecular effects, leading to faster reaction dynamics and low Zn2+ transfer resistance. P3Q‐t affords a high capacity of 237 mAh g–1 at 0.3 A g–1. More importantly, such capacity can be retained for 45% at 15 A g–1 and an average 81% of capacity retention is achieved over 1500 cycles.
Improved Low‐Temperature Performance of Rocking‐Chair Sodium‐Ion Hybrid Capacitor by Mitigating the De‐Solvation Energy and Interphase Resistance
Authors: Yang Jinyu , Ruan Jiafeng , Li Qin , Fang Fang , Song Yun , Sun Dalin , Wang Fei 
Published: April 2022

AbstractHybrid capacitors, which bear the advantages of secondary batteries and supercapacitors, can deliver high power with a relatively fair amount of energy. However, its kinetic performance, especially at low temperatures, is strongly limited by the battery‐type electrode and electrolyte. In this work, Na‐ion, which has a lower solvation energy than Li‐ion, is chosen as the charge carrier to build the hybrid capacitor. A sodium‐ion hybrid capacitor is built with an activated carbon cathode and a pre‐sodiated hard carbon anode. To achieve a better kinetic performance, the de‐solvation energy and interphase resistance is decreased through replacing conventional carbonate electrolyte with a diethylene glycol dimethyl ether (DEGDME) based electrolyte. As a result, the sodium‐ion capacitor delivers an energy density of 42 Wh kg–1 and a high power of 4565 W kg–1 for 3000 cycles at 2.5 A g–1. Furthermore, this capacitor could sustain an energy density of 36 Wh kg–1 at the low temperature of −30 °C and maintain 70% of the capacity after 500 cycles. The strategies of reducing de‐solvation energy and optimizing the solid electrolyte interphase property offers a clear path for developing electrochemical energy storage devices at lower temperatures.
Sharing of Strain Between Nanofiber Forests and Liquid Crystals Leads to Programmable Responses to Electric Fields
Authors: Roh Sangchul , Kim John , Varadharajan Divya , Lahann Joerg , Abbott Nicholas L. 
Published: April 2022

AbstractFibers embedded in soft matrices are widely encountered in biological systems, with the fibers providing mechanical reinforcement or encoding of instructions for shape changes. Here, the mechanical coupling of end‐attached polymeric nanofiber forests and liquid crystals (LCs) is explored, where the nanofibers are templated into prescribed shapes by the chemical vapor polymerization of paracyclophane‐based monomers in supported films of the LCs. It is shown that the elastic energies of the nanofibers and LCs are comparable in magnitude, leading to reversible straining of nanofibers via the application of an electric field to the LC. This coupling is shown to encode complex electrooptical responses in the LC (e.g., optical vortices), thus illustrating how LC‐templated nanofiber forests offer the basis of fresh approaches for programming configurational changes in soft materials.
Directional and Adaptive Oil Self‐Transport on a Multi‐Bioinspired Grooved Conical Spine
Authors: Li Yaoxia , Cui Zehang , Li Guoqiang , Bai Haoyu , Dai Ruyuan , Zhou Yingzi , Jiao Yan , Song Yuegan , Yang Yi , Liu Senyun , Cao Moyuan 
Published: April 2022

AbstractManipulating oil droplets in an aqueous solution offers great opportunities to develop advanced devices in the fields of water remediation, chemical micro‐reactor, etc. Although conical structures can achieve a directional oil droplet motion, the continuous and adaptive fluid self‐transport in complicated environments is still a challenge. Inspired by the distinctive oil transport capability of fishbone and the anisotropic grooved structure of rice leaves, this work presents a multi‐bioinspired grooved conical spine (BGCS) for improved oil manipulation. Benefiting from the cooperative effect of the asymmetric Laplace pressure and the surface capillary force, the BGCS possesses the reliable functions of ultrafast and continuous oil transport under water, in air, and even across the air–water interface. Compared with the original cone, the BGCS demonstrates a nine times faster transporting velocity and a five times larger capacity. It is envisioned that this updated oil‐collecting cone with its cooperative structure should find real‐world applications.
Robust Memristive Fiber for Woven Textile Memristor
Authors: Liu Yue , Zhou Xufeng , Yan Hui , Zhu Zhengfeng , Shi Xiang , Peng Yahui , Chen Lin , Chen Peining , Peng Huisheng 
Published: April 2022

AbstractMemristors with an intrinsic crossbar structure and high computing capability offer promising opportunities for the flexible information‐processing component that can well integrate with the interwoven structure of electronic textiles. However, it remains difficult to achieve uniform inorganic memristive layer at nanometer thickness on the curved surface of fiber electrode, thus hindering the applications of textile memristors. Here, a high‐performing and reliable textile memristor made of robust Pt/CsPbBr3 fiber through an electric‐field‐assisted assembly method is reported. The textile memristor exhibits a cycle to cycle variation of less than 8% and an average set voltage of ≈0.16 V, which is lower than that of the majority of planar metal‐oxide memristors. The flexible and mechanically robust Pt/CsPbBr3 fibers are woven into a scalable textile memristor array with good device‐to‐device reproducibility. This textile memristor can be seamlessly integrated with textile electronics toward a smart clothes system to accurately process complicated physiological information, providing an effective interactive interface for intelligent healthcare.
Degradable Silk‐Based Subcutaneous Oxygen Sensors
Authors: Falcucci Thomas , Presley Kayla F. , Choi Jaewon , Fizpatrick Vincent , Barry Jonah , Kishore Sahoo Jugal , Ly Jack T. , Grusenmeyer Tod A. , Dalton Matthew J. , Kaplan David L. 
Published: April 2022

AbstractContinuous monitoring of biochemical analytes like oxygen is of interest in biomedicine to provide insight into physiology and health. Silk‐protein biomaterials are particularly useful as the scaffold material in oxygen sensors due to silk's unique amphiphilic chemistry, which promotes noncovalent stabilization of the protein and additives in aqueous environments. Silk films containing a water‐insoluble oxygen‐sensing chromophore, Pd (II) tetramethacrylated benzoporphyrin (PdBMAP), are evaluated as optical oxygen sensors in vitro and in vivo. These silk‐chromophore composites are stabilized by the self‐assembled, physically crosslinked protein network. The deaerated phosphorescence lifetime (τm,0 ≈300 µs) of the chromophore in vitro is quenched to 50% of its initial value at ≈31 µm dissolved oxygen, indicating sensing functionality within physiological ranges of oxygen. In vitro enzymatic degradation of the silk films with and without the chromophore is demonstrated. The silk‐chromophore composite films are cytocompatible in vitro, biocompatible in vivo upon implantation in rats, and displayed mechanical properties suitable for subcutaneous implantation. Further, the films maintain oxygen‐sensing function in vivo and demonstrate real‐time sensing capabilities throughout various physiological states (i.e., hyperoxia, normoxia, and hypoxia).
Multimodal Gas Sensor Detecting Hydroxyl Groups with Phase Transition Based on Eco‐Friendly Lead‐Free Metal Halides
Authors: Lee Daseul , Lee Seung‐Jea , Kim Jae Ho , Park Juyun , Kang Yong‐Cheol , Song Myungkwan , Lee Hyung Woo , Kim Han Seul , Choi Jin Woo 
Published: April 2022

AbstractAn electrical and optical responsive chemical‐semiconductor gas sensor is developed using Cu(I) halides with a phase transition mechanism. Cu(I) materials exhibit reversible phase transitions between the Cs3Cu2I5 and CsCu2I3 with different properties, owing to the formation/destruction of the Cs–I and Cu–Cu bonding when the hydroxyl groups are attached/detached. Among various toxic and atmospheric gases, a Cu(I)‐based gas sensor has high selectivity in detecting the hydroxyl group, and the highest sensitivity to water. The reactivity is determined by the polarity, where water with the largest polarity has the strongest attraction for Cu+ and I− ions, letting phase transition occur easily. The multimodal sensor red‐shifts emission from 445 to 575 nm when it detects hydroxyl gas, and the moisture‐sensitive sensor visually confirms response to breaths in less than 5 s and recovery in the air in less than 30 s. The gas sensor can operate at room temperature while applying a constant bias voltage of 1 V, and it also shows excellent sensitivity in a relative humidity range of 15–75%. Furthermore, the sensor maintained ≈90% of its initial responsivity over 1 year.
Aerodynamics‐Based Triboelectric Nanogenerator for Enhancing Multi‐Operating Robustness via Mode Automatic Switching
Authors: Liu Yuan , Yan Wenjie , Han Jiajia , Chen Baodong , Wang Zhong Lin 
Published: April 2022

AbstractThe multi‐operating robustness of triboelectric nanogenerators (TENGs) is still an awkward issue that must be solved to achieve practicality and industrialization. Here, an aerodynamics‐based TENG (AB‐TENG) is developed by combining it with a propeller and rotor, which can switch automatically between contact and separation mode. The separation speed can be reduced to 150 rpm by optimizing the spring stiffness coefficient, which maintains 95.18% of the electrical output after continuous operation for more than 1.378 million cycles. Combining with power management circuit, these capacitors of 0.56, 1, 3.3, and 10 mF can be charged quickly to 3 V within 7.3, 9.3, 16.7, and 43.4 s, respectively. In addition, AB‐TENG can power 6 digital hygrothermographs in parallel by harvesting irregular airflow or drive one Bluetooth‐enabled, 6 commercial LED bulbs of 3 W or 240 green LED lamp beads in parallel, respectively. This work provides an effective strategy to improve the multi‐operating robustness of TENGs, and more importantly, to overcome the mechanical durability and electrical stability difficulties of the technique at high rotational speed caused by abrasion limit of triboelectric materials, and may reveal its potential in the distributed energy and Internet of Things.
Characteristics of ALD‐ZnO Thin Film Transistor Using H2O and H2O2 as Oxygen Sources
Authors: Yang Jun , Bahrami Amin , Ding Xingwei , Lehmann Sebastian , Kruse Nadine , He Shiyang , Wang Bowen , Hantusch Martin , Nielsch Kornelius 
Published: April 2022

AbstractZnO thin films are deposited by atomic layer deposition (ALD) using diethylzinc as the Zn source and H2O and H2O2 as oxygen sources. The oxidant‐ and temperature‐dependent electrical properties and growth characteristics are systematically investigated. Materials analysis results suggest that H2O2 provides an oxygen‐rich environment so that the oxygen vacancies (VO) is suppressed, implying a lower carrier concentration and a higher resistivity. The lower growth rate makes it possible for the ZnO thin films to grow along the lower surface energy direction of <002>, leading to a lower Hall mobility. Furthermore, the ZnO semiconductor is integrated into thin film transistor (TFT) devices and the electrical properties are analyzed. The TFT with H2O2‐ZnO grown at 150 °C shows good electrical properties, such as a high field‐effect mobility of 10.7 cm2 V–1 s–1, a high ratio Ion/Ioff of 2 × 107, a sharp subthreshold swing of 0.25 V dec–1, and a low trapping state (Ntrap) of 2.77 × 1012 eV–1 cm–2, which provides a new pathway to optimize the performance of metal‐oxide electronics.
Tuning the Optical and Electrical Properties of Polymer‐Based Nanocomposites by Plasmon‐Induced Electromagnetic Field
Authors: Peng Shih‐Lun , Chen Gang‐Yi , Hsu Su‐Wen 
Published: April 2022

AbstractFor nanocomposites composed of plasmonic nanocrystal and polymers, the plasmon‐induced electromagnetic field (EF) around the plasmonic nanocrystals can be used to change the dielectric environment around them, resulting in the optical and electrical properties of nanocomposites being adjustable. The electrical conductivities of ligand coated on plasmonic nanocrystal and polymer matrix play important roles in controlling the “local” and “overall” dielectric environment of nanocomposites under plasmon‐induced EF. The changes in the dielectric environment of nanocomposites are caused by the rearrangement of molecular chains of ligand and/or polymer matrix around the plasmonic nanocrystals. The optical properties of nanocomposites depend on the “local” and “overall” dielectric environment of nanocomposites, which show a significant change in the plasmon resonance wavelength (blueshift ≈10 nm) under plasmon‐induced EF. However, the electrical properties of nanocomposites depend only on the “overall” dielectric environment of the nanocomposite under plasmon‐induced EF. Nanocomposites are constructed in the conducting polymer matrix resulting in three orders of magnitude increase (from 4 × 10–14 to 10–10 s cm−1) in the electrical conductivity of nanocomposites under plasmon‐induced EF. Such plasmonic nanocrystal‐polymer nanocomposites with highly sensitive optical and electrical properties under external stimuli have potential applications in “electromagnetic field” or “photonic” sensors.