bluuebunny/crossref_metadata_2025_split huggingface dataset:
Recent Progress of the Lifetime of Organic Light‐Emitting Diodes Based on Thermally Activated Delayed Fluorescent Material
Authors: Jeon Sang Kyu , Lee Ha Lim , Yook Kyoung Soo , Lee Jun Yeob 
Published: March 2019

AbstractRecently, the external quantum efficiency and lifetime of organic light‐emitting diodes (OLEDs) have been dramatically upgraded due to development of organic materials and device structure. In particular, an intramolecular or intermolecular complex based on thermally activated delayed fluorescent (TADF) materials has greatly contributed to improving OLED device performance. Although high external quantum efficiency has been the main objective of the development of TADF materials as hosts and emitters, recent interest has been directed towards the lifetime of TADF‐material‐based OLEDs. For the past several years, remarkable advances in the lifetime of phosphorescent and TADF OLEDs have been made using TADF materials as hosts or emitters in the emitting layer. Therefore, since TADF materials are useful as both hosts and emitters for a long lifetime, this work discusses the recent progress made in developing TADF materials for long‐lifetime OLEDs.
Synaptic Resistors for Concurrent Inference and Learning with High Energy Efficiency
Authors: Danesh Cameron D. , Shaffer Christopher M. , Nathan Dhruva , Shenoy Rahul , Tudor Andrew , Tadayon Macan , Lin Yvette , Chen Yong 
Published: March 2019

AbstractThe fastest supercomputer, Summit, has a speed comparable to the human brain, but is much less energy‐efficient (≈1010 FLOPS W−1, floating point operations per second per watt) than the brain (≈1015 FLOPS W−1). The brain processes and learns from “big data” concurrently via trillions of synapses in parallel analog mode. By contrast, computers execute algorithms on physically separated logic and memory transistors in serial digital mode, which fundamentally restrains computers from handling “big data” efficiently. The existing electronic devices can perform inference with high speeds and energy efficiencies, but they still lack the synaptic functions to facilitate concurrent convolutional inference and correlative learning efficiently like the brain. In this work, synaptic resistors are reported to emulate the analog convolutional signal processing, correlative learning, and nonvolatile memory functions of synapses. By circumventing the fundamental limitations of computers, a synaptic resistor circuit performs speech inference and learning concurrently in parallel analog mode with an energy efficiency of ≈1.6 × 1017 FLOPS W−1, which is about seven orders of magnitudes higher than that of the Summit supercomputer. Scaled‐up synstor circuits could circumvent the fundamental limitations in computers, and facilitate real‐time inference and learning from “big data” with high efficiency and speed in intelligent systems.
Dual‐Phase Single‐Ion Pathway Interfaces for Robust Lithium Metal in Working Batteries
Authors: Xu Rui , Xiao Ye , Zhang Rui , Cheng Xin‐Bing , Zhao Chen‐Zi , Zhang Xue‐Qiang , Yan Chong , Zhang Qiang , Huang Jia‐Qi 
Published: March 2019

AbstractThe lithium (Li) metal anode is confronted by severe interfacial issues that strongly hinder its practical deployment. The unstable interfaces directly induce unfavorable low cycling efficiency, dendritic Li deposition, and even strong safety concerns. An advanced artificial protective layer with single‐ion pathways holds great promise for enabling a spatially homogeneous ionic and electric field distribution over Li metal surface, therefore well protecting the Li metal anode during long‐term working conditions. Herein, a robust dual‐phase artificial interface is constructed, where not only the single‐ion‐conducting nature, but also high mechanical rigidity and considerable deformability can be fulfilled simultaneously by the rational integration of a garnet Al‐doped Li6.75La3Zr1.75Ta0.25O12‐based bottom layer and a lithiated Nafion top layer. The as‐constructed artificial solid electrolyte interphase is demonstrated to significantly stabilize the repeated cell charging/discharging process via regulating a facile Li‐ion transport and a compact Li plating behavior, hence contributing to a higher coulombic efficiency and a considerably enhanced cyclability of lithium metal batteries. This work highlights the significance of rational manipulation of the interfacial properties of a working Li metal anode and affords fresh insights into achieving dendrite‐free Li deposition behavior in a working battery.
Phase‐Change Hyperbolic Heterostructures for Nanopolaritonics: A Case Study of hBN/VO2
Authors: Dai Siyuan , Zhang Jiawei , Ma Qiong , Kittiwatanakul Salinporn , McLeod Alex , Chen Xinzhong , Corder Stephanie Gilbert , Watanabe Kenji , Taniguchi Takashi , Lu Jiwei , Dai Qing , Jarillo‐Herrero Pablo , Liu Mengkun , Basov D. N. 
Published: March 2019

AbstractUnlike conventional plasmonic media, polaritonic van der Waals (vdW) materials hold promise for active control of light–matter interactions. The dispersion relations of elementary excitations such as phonons and plasmons can be tuned in layered vdW systems via stacking using functional substrates. In this work, infrared nanoimaging and nanospectroscopy of hyperbolic phonon polaritons are demonstrated in a novel vdW heterostructure combining hexagonal boron nitride (hBN) and vanadium dioxide (VO2). It is observed that the insulator‐to‐metal transition in VO2 has a profound impact on the polaritons in the proximal hBN layer. In effect, the real‐space propagation of hyperbolic polaritons and their spectroscopic resonances can be actively controlled by temperature. This tunability originates from the effective change in local dielectric properties of the VO2 sublayer in the course of the temperature‐tuned insulator‐to‐metal phase transition. The high susceptibility of polaritons to electronic phase transitions opens new possibilities for applications of vdW materials in combination with strongly correlated quantum materials.
Expandable Immunotherapeutic Nanoplatforms Engineered from Cytomembranes of Hybrid Cells Derived from Cancer and Dendritic Cells
Authors: Liu Wen‐Long , Zou Mei‐Zhen , Liu Tao , Zeng Jin‐Yue , Li Xue , Yu Wu‐Yang , Li Chu‐Xin , Ye Jing‐Jie , Song Wen , Feng Jun , Zhang Xian‐Zheng 
Published: March 2019

AbstractUsing the cytomembranes (FMs) of hybrid cells acquired from the fusion of cancer and dendritic cells (DCs), this study offers a biologically derived platform for the combination of immunotherapy and traditional oncotherapy approaches. Due to the immunoactivation implicated in the cellular fusion, FMs can effectively express whole cancer antigens and immunological co‐stimulatory molecules for robust immunotherapy. FMs share the tumor's self‐targeting character with the parent cancer cells. In bilateral tumor‐bearing mouse models, the FM‐coated nanophotosensitizer causes durable immunoresponse to inhibit the rebound of primary tumors post‐nanophotosensitizer‐induced photodynamic therapy (PDT). The FM‐induced immunotherapy displays ultrahigh antitumor effects even comparable to that of PDT. On the other hand, PDT toward primary tumors enhances the immunotherapy‐caused regression of the irradiation‐free distant tumors. Consequently, both the primary and the distant tumors are almost completely eliminated. This tumor‐specific immunotherapy‐based nanoplatform is potentially expandable to multiple tumor types and readily equipped with diverse functions owing to the flexible nanoparticle options.
Uniform Distribution of Alloying/Dealloying Stress for High Structural Stability of an Al Anode in High‐Areal‐Density Lithium‐Ion Batteries
Authors: Zhang Miao , Xiang Lei , Galluzzi Massimiliano , Jiang Chunlei , Zhang Shanqing , Li Jiangyu , Tang Yongbing 
Published: March 2019

AbstractAluminum (Al) is one of the most attractive anode materials for lithium‐ion batteries (LIBs) due to its high theoretical specific capacity, excellent conductivity, abundance, and especially low cost. However, the large volume expansion, originating from the uneven alloying/dealloying reactions in the charge/discharge process, causes structural stress and electrode pulverization, which has long hindered its practical application, especially when assembled with a high‐areal‐density cathode. Here, an inactive (Cu) and active (Al) co‐deposition strategy is reported to homogeneously distribute the alloying sites and disperse the stress of volume expansion, which is beneficial to obtain the structural stability of the Al anode. Owing to the homogeneous reaction and uniform distribution of stress during the charge/discharge process, the assembled full battery (LiFePO4 cathode with a high areal density of ≈7.4 mg cm−2) with the Cu–Al@Al anode, achieves a high capacity retention of ≈88% over 200 cycles, suggesting the feasibility of the interfacial design to optimize the structural stability of alloying metal anodes for high‐performance LIBs.
Nanoprinted Quantum Dot–Graphene Photodetectors
Authors: Grotevent Matthias J. , Hail Claudio U. , Yakunin Sergii , Dirin Dmitry N. , Thodkar Kishan , Borin Barin Gabriela , Guyot‐Sionnest Philippe , Calame Michel , Poulikakos Dimos , Kovalenko Maksym V. , Shorubalko Ivan 
Published: March 2019

AbstractPhotodetectors utilizing graphene field‐effect transistors sensitized by colloidal quantum dots exhibit high responsivities under infrared light illumination. Precise, microscopic spatial control over quantum dot deposition is required to gain deeper insight into device mechanisms, optimize device performance, and enable new device architectures and applications. The latter may eventually include photodetectors with subwavelength device dimensions. Here, infrared photodetectors are fabricated by electrohydrodynamic nanoprinting of colloidal PbS quantum dots onto graphene field‐effect transistors with varying quantum dot layer thicknesses on a single substrate, demonstrating the potential of the method for realizing small footprint detectors with high spatial resolution. Remarkably, while the responsivity of the photodetectors increases with increasing layer thicknesses up to 130 nm, the noise current is found to be independent of the layer thickness. In addition, the responsivity and noise current are both linearly dependent on the applied drain voltage and drain current. As a result, the specific detectivity is independent of the drain voltage, and the detector can be operated at lower drain voltages thus reducing power consumption. Finally, specific detectivities of at least 109 Jones at 1200 nm are obtained, without degradation of the charge carrier mobilities in graphene from the electrohydrodynamic printing.
Isomeric Bright Sky‐Blue TADF Emitters Based on Bisacridine Decorated DBNA: Impact of Donor Locations on Luminescent and Electroluminescent Properties
Authors: Meng Guoyun , Chen Xing , Wang Xiang , Wang Nan , Peng Tai , Wang Suning 
Published: March 2019

AbstractThree isomeric boron‐containing thermally activated delayed fluorescent (TADF) emitters, namely m‐AC‐DBNA, p‐AC‐DBNA, and m′‐AC‐DBNA, are constructed by incorporating an electron‐donor acridine (AC) moiety into meta‐, para‐, or meta′‐positions of an electron‐accepting boron‐embedded rigid framework. The substitutional positions are found to dramatically affect thermal, photophysical, and electroluminescent (EL) properties. The experimental results show that the para‐substituted compound (p‐AC‐DBNA) exhibits higher decomposition temperature, higher photoluminescence (PL) quantum efficiencies, smaller singlet–triplet energy splitting, shorter delayed fluorescence lifetimes as well as a fast reverse intersystem crossing rate of over 106 s−1, compared to the meta‐isomers (m‐AC‐DBNA and m′‐AC‐DBNA). Bright and highly efficient organic light‐emitting diodes (OLEDs) with external quantum efficiencies (EQEs) up to 20.5% and 14.1% are achieved by employing p‐AC‐DBNA as doped and nondoped emitters in sky‐blue OLEDs, respectively. Moreover, excellent doping‐concentration independent EL properties and very low efficiency roll‐off at a high luminance are achieved. This isomeric strategy provides a simple method to extend structural diversity of highly efficient TADF emitters, optimize optoelectronic properties, and demonstrate the relationship of delayed fluorescence lifetime and efficiency roll‐off of the TADF devices. The three isomers also display distinct temperature‐dependent emission and mechanochromism.
Random Mutagenesis‐Driven Improvement of Carboxylate Reductase Activity using an Amino Benzamidoxime‐Mediated High‐Throughput Assay
Authors: Schwendenwein Daniel , Ressmann Anna K. , Doerr Mark , Höhne Matthias , Bornscheuer Uwe T. , Mihovilovic Marko D. , Rudroff Florian , Winkler Margit 
Published: March 2019

AbstractCarboxylic acid reductases (CARs) catalyze the direct adenosine triphosphate (ATP) and nicotinamide adenine dinucleotide phosphate (NADPH) dependent reduction of carboxylic acids to their corresponding aldehydes. The identification and improvement of CARs by protein engineering is, however, severely limited by the lack of fast and generic methods to quantify aldehydes. Within this study, we applied a convenient high‐throughput assay (HTA) based on amino benzamidoxime (ABAO) that allows the substrate‐independent and chemoselective quantification of aldehydes. Random mutagenesis of the well‐known CAR from Nocardia iowensis (CARNi) to improve its activity for sterically demanding 2‐substituted benzoic acid derivatives was conducted in a KM‐dependent fashion, and the HTA applied in the presence of microbial cells. The study identified a hot spot in the active site of CARNi that increased the affinity to 2‐methoxybenzoic acid 9‐fold upon mutation from glutamine to proline (Q283P). The catalytic performance of CARNiQ283P appeared to be significantly improved also for other substrates such as 2‐substituted (2‐Cl, 2‐Br) as well as 3‐ and 4‐substituted benzoic acids (3‐OMe, 4‐OMe), and even aliphatic octanoic acid.magnified image
Synergetic Effect of Ultrasmall Metal Clusters and Zeolites Promoting Hydrogen Generation
Authors: Sun Qiming , Wang Ning , Bai Risheng , Hui Yu , Zhang Tianjun , Do David A. , Zhang Peng , Song Lijuan , Miao Shu , Yu Jihong 
Published: March 2019

AbstractTaking advantage of the synergetic effect of confined ultrasmall metal clusters and zeolite frameworks is an efficient strategy for improving the catalytic performance of metal nanocatalysts. Herein, it is demonstrated that the synergetic effect of ultrasmall ruthenium (Ru) clusters and intrinsic Brønsted acidity of zeolite frameworks can significantly promote the hydrogen generation of ammonia borane (AB) hydrolysis. Ultrasmall Ru clusters are embedded onto the silicoaluminophosphate SAPO‐34 (CHA) and various aluminosilicate zeolites (MFI, *BEA, and FAU) with tunable acidities by a facile incipient wetness impregnation method. Evidenced by high‐resolution scanning transmission electron microscopy, the sub‐nanometric Ru clusters are uniformly distributed throughout the zeolite crystals. The X‐ray absorption spectroscopy measurements reveal the existence of Ru‐H species between Ru clusters and adjacent Brønsted acid sites of zeolites, which could synergistically activate AB and water molecules, significantly enhancing the hydrogen evolution rate of AB hydrolysis. Notably, the Ru/SAPO‐34‐0.8Si (Si/Al = 0.8) and Ru/FAU (Si/Al = 30) catalysts with strong acidities afford high turnover frequency values up to 490 and 627 min−1, respectively. These values are more than a 13‐fold enhancement than that of the commercial Ru/C catalyst, and among the top level over other heterogeneous catalysts tested under similar conditions.
Alkali Chlorides for the Suppression of the Interfacial Recombination in Inverted Planar Perovskite Solar Cells
Authors: Chen Wei , Zhou Yecheng , Chen Guocong , Wu Yinghui , Tu Bao , Liu Fang‐Zhou , Huang Li , Ng Alan Man Ching , Djurišić Aleksandra B. , He Zhubing 
Published: March 2019

AbstractIn this work, significant suppression of the interfacial recombination by facile alkali chloride interface modification of the NiOx hole transport layer in inverted planar perovskite solar cells is achieved. Experimental and theoretical results reveal that the alkali chloride interface modification results in improved ordering of the perovskite films, which in turn reduces defect/trap density, causing reduced interfacial recombination. This leads to a significant improvement in the open‐circuit voltage from 1.07 eV for pristine NiOx to 1.15 eV for KCl‐treated NiOx, resulting in a power conversion efficiency approaching 21%. Furthermore, the suppression of the ion diffusion in the devices is observed, as evidenced by stable photoluminescence (PL) under illumination and high PL quantum efficiency with alkali chloride treatment, as opposed to the luminescence enhancement and low PL quantum efficiency observed for perovskite on pristine NiOx. The suppressed ion diffusion is also consistent with improved stability of the devices with KCl‐treated NiOx. Thus, it is demonstrated that a simple interfacial modification is an effective method to not only suppress interfacial recombination but also to suppress ion migration in the layers deposited on the modified interface due to improved interface ordering and reduced defect density.
Variation in breast milk macronutrient contents by maternal anemia and hemoglobin concentration in northern Kenya
Authors: Corbitt Mary , Paredes Ruvalcaba Nerli , Fujita Masako 
Published: March 2019

AbstractObjectivesThis study explored differing levels of macronutrients in breast milk in relation to maternal anemia and hemoglobin.MethodsArchived milk specimens and data from a cross‐sectional sample of 208 breastfeeding mothers in northern Kenya, originally collected in 2006, were analyzed; data included milk fat, maternal hemoglobin concentration, and anemia status (anemia defined as hemoglobin <12 g/dL). Total protein and lactose were measured and energy was calculated. To explore the association between milk outcomes (fat, protein, lactose, and energy) and anemia, regression models were constructed with and without adjustment for maternal age, parity, and time (days) postpartum. The same models were constructed using hemoglobin as a continuous predictor in lieu of dichotomous anemia to explore the role of hemoglobin levels and anemia severity in predicting milk outcomes.ResultsThe group comparison indicated significantly higher milk protein and lower milk fat for anemic mothers relative to nonanemic counterparts. After adjustment for maternal age, parity, and time postpartum, maternal anemia was associated with significantly higher milk protein (P = 0.001) and significantly lower milk fat (P = 0.025). Hemoglobin had a significant inverse relationship with milk protein (P = 0.017) and a marginally significant positive relationship with milk fat (P = 0.060) after adjusting for the maternal variables. Neither anemia nor hemoglobin was significant in predicting lactose or milk energy.ConclusionsMaternal anemia and hemoglobin concentration may be associated with complex changes in milk macronutrients. Future research should clarify the impact of maternal anemia on a range of breast milk components while accounting for other maternal characteristics.
One‐Step Implementation of N‐Qubit Nonadiabatic Holonomic Quantum Gates with Superconducting Qubits via Inverse Hamiltonian Engineering
Authors: Kang Yi‐Hao , Chen Ye‐Hong , Shi Zhi‐Cheng , Huang Bi‐Hua , Song Jie , Xia Yan 
Published: March 2019

AbstractA protocol is proposed to realize one‐step implementation of the N‐qubit nonadiabatic holonomic quantum gates with superconducting qubits. The inverse Hamiltonian engineering is applied in designing microwave pulses to drive superconducting qubits. By combining curve fitting, the wave shapes of the designed pulses can be described by simple functions, which are not hard to realize in experiments. To demonstrate the effectiveness of the protocol, a three‐qubit holonomic controlled π‐phase gate is taken as an example in numerical simulations. The results show that the protocol holds robustness against noise and decoherence. Therefore, the protocol may provide an alternative approach for implementing N‐qubit nonadiabatic holonomic quantum gates.
Doping‐Induced Amorphization, Vacancy, and Gradient Energy Band in SnS2Nanosheet Arrays for Improved Photoelectrochemical Water Splitting
Authors: Meng Linxing , Wang Siyu , Cao Fengren , Tian Wei , Long Run , Li Liang 
Published: March 2019

AbstractPhotoelectrochemical (PEC) water splitting is a promising strategy to convert solar energy into hydrogen fuel. However, the poor bulk charge‐separation ability and slow surface oxygen evolution reaction (OER) dynamics of photoelectrodes impede the performance. We construct In‐ and Zn/In‐doped SnS2nanosheet arrays through a hydrothermal method. The doping induces the simultaneous formation of an amorphous layer, S vacancies, and a gradient energy band. This leads to elevated carrier concentrations, an increased number of surface‐reaction sites, accelerated surface‐OER kinetics, and an enhanced bulk‐carrier separation efficiency with a decreased recombination rate. This efficient doping strategy allows to manipulate the morphology, crystallinity, and band structure of photoelectrodes for an improved PEC performance.
Direct Observation and Analysis of the Dynamics of the Photoresponsive Transcription Factor GAL4
Authors: Raghavan Guruprasad , Hidaka Kumi , Sugiyama Hiroshi , Endo Masayuki 
Published: March 2019

AbstractHerein, the direct visualization of the dynamic interaction between a photoresponsive transcription factor fusion, GAL4–VVD, and DNA using high‐speed atomic force microscopy (HS‐AFM) is reported. A series of different GAL4–VVD movements, such as binding, sliding, stalling, and dissociation, was observed. Inter‐strand jumping on two double‐stranded (ds) DNAs was also observed. Detailed analysis using a long substrate DNA strand containing five GAL4‐binding sites revealed that GAL4–VVD randomly moved on the dsDNA using sliding and hopping to rapidly find specific binding sites, and then stalled to the specific sites to form a stable complex formation. These results suggest the existence of different conformations of the protein to enable sliding and stalling. This single‐molecule imaging system with nanoscale resolution provides an insight into the searching mechanism used by DNA‐binding proteins.