bluuebunny/crossref_metadata_2025 huggingface dataset:
All‐Fluorescence White Organic Light‐Emitting Diodes Exceeding 20% EQEs by Rational Manipulation of Singlet and Triplet Excitons
Authors: Tang Xun , Li Yun , Qu Yang‐Kun , Peng Chen‐Chen , Khan Aziz , Jiang Zuo‐Quan , Liao Liang‐Sheng
Published: February 2020

White organic light‐emitting diodes (WOLEDs) composed of conventional fluorophores possess color purity, low efficiency roll‐off, and rare metal absence, but suffer from theoretical limits due to the lack of triplet utilization. Due to the different diffusion distance for singlets and triplets, multiple Förster resonance energy transfer (FRET) channels can be adequately built up. Herein, besides the complementary component, a blue fluorescence layer, hosted by pure hydrocarbon material SF4‐TPE, is put forward as the spatial exciton manipulating layer to rationally allocate singlets and triplets to the corresponding channels. Hence, singlets are captured by the blue fluorophore, diffused triplets subsequently undergo energy resonance between the blue fluorophore and green assistant, and up‐conversion effect for eventual emission from the yellow fluorophore. Owing to the utilization of singlets and triplets, all‐fluorescence WOLEDs exhibit high efficiency exceeding 20%, with slight efficiency roll‐off even under high luminance of 5000 cd cm−2. Moreover, CIE coordinates can be surrounding and precisely inside the American National Standard Institute (ANSI) quadrangles, as well as outstanding color stability (ΔCIE‐(x, y) within (0.001, 0.012)) from 300 to 13000 cd cm−2.
Heterointerface Engineering of Hierarchical Bi2S3/MoS2 with Self‐Generated Rich Phase Boundaries for Superior Sodium Storage Performance
Authors: Cao Liang , Liang Xinghui , Ou Xing , Yang Xianfeng , Li Yangzhong , Yang Chenghao , Lin Zhang , Liu Meilin
Published: February 2020

Regulating nanocrystal composition with multiphase compounds is considered an efficient approach to enhance electrochemical performance and structure stability. Nevertheless, the thorough understanding of significant reaction mechanisms and insight into the reason of enhanced performance is still urgent. In this work, the bimetallic sulfide Bi2S3/MoS2 heterogeneous with abundant phase boundaries is successfully fabricated. The in situ investigation of Na+‐storage mechanism confirms that enormous phase boundaries are self‐generated by composition optimization and rational structural design. More importantly, the full understanding of abundant phase boundaries on the enhanced electrochemical properties is explicitly unraveled by combining theoretical analysis and experimental results. It confirms that the interior self‐built‐in electric‐field induced by phase boundaries can enhance the reaction kinetics and boost the charge transfer. Besides, the Bi/Na2S interface is well‐maintained by the homogeneously distributed phase boundaries, effectively improving the conversion/alloying reversibility and keeping integrity without agglomeration and pulverization. As expected, the Bi2S3/MoS2 composite exhibits superior rate capability and long‐cycling stability (323.4 mAh g−1 after long‐term 1200 cycles at ultrahigh rate of 10 A g−1). This strategy of constructing sufficient phase boundaries sheds light on the enhancement of reversibility and stability for other advanced conversion/alloying‐type anode materials.
Recapitulating and Deciphering Tumor Microenvironment by Using 3D Printed Plastic Brick–Like Microfluidic Cell Patterning
Authors: Liu Yang , Liu Yingying , Zheng Xiaonan , Zhao Liang , Zhang Xueji
Published: February 2020

Within the body, tumor cells are surrounded by neighboring counterparts, such as extracellular matrix, vasculature, and host stroma, which is also known as the tumor microenvironment. To understand tumorigenesis, it is essential to reconstitute the incorporative tumor niche with quantitative measurements in vitro. Here, a 3D printed plastic brick–like microfluidic gadget is developed for spatially patterning tumors and fibroblasts, enabling the recapitulation of tumor microenvironment with minimized microfluidic expertise and compatibility of standard pipetting. This method facilitates heterotypic coculturing, quantitative phenotype decoding, and downstream molecular assays with a small number of cells (less than 100). Phenotypic and gene/protein expression‐based analysis of cell–cell interactions between fibrosarcoma cells and fibroblasts on this device reveals that the tumor and its counterparts show reciprocal synergism mainly by upregulation of proinflammatory cytokines. Notably, at the whole transcriptional landscape (RNA‐seq), fibroblasts display a transition from normal to cancer‐associated fibroblast (CAF)‐like phase, and tumor cells exhibit a hyperactive ribosome biogenesis. The mouse xenograft model is also involved to validate the in vitro analysis. Given its easy‐to‐use feature, full compatibility with molecular analysis, and open‐source accessibility, this approach provides an in vitro experimental system to advance knowledge of tumorigenesis and the corresponding tumor microenvironment.
Superhigh Electromagnetic Interference Shielding of Ultrathin Aligned Pristine Graphene Nanosheets Film
Authors: Wei Qinwei , Pei Songfeng , Qian Xitang , Liu Haopeng , Liu Zhibo , Zhang Weimin , Zhou Tianya , Zhang Zhangcai , Zhang Xuefeng , Cheng Hui‐Ming , Ren Wencai
Published: February 2020

Ultrathin, lightweight, high‐strength, and thermally conductive electromagnetic interference (EMI) shielding materials with high shielding effectiveness (SE) are highly desired for next‐generation portable and wearable electronics. Pristine graphene (PG) has a great potential to meet all the above requirements, but the poor processability of PG nanosheets hinders its applications. Here, efficient synthesis of highly aligned laminated PG films and nacre‐like PG/polymer composites with a superhigh PG loading up to 90 wt% by a scanning centrifugal casting method is reported. Due to the PG‐nanosheets‐alignment‐induced high electrical conductivity and multiple internal reflections, such films show superhigh EMI SE comparable to the reported best synthetic material, MXene films, at an ultralow thickness. An EMI SE of 93 dB is obtained for the PG film at a thickness of ≈100 µm, and 63 dB is achieved for the PG/polyimide composite film at a thickness of ≈60 µm. Furthermore, such PG‐nanosheets‐based films show much higher mechanical strength (up to 145 MPa) and thermal conductivity (up to 190 W m−1 K−1) than those of their MXene counterparts. These excellent comprehensive properties, along with ease of mass production, pave the way for practical applications of PG nanosheets in EMI shielding.
Emergence of Nontrivial Low‐Energy Dirac Fermions in Antiferromagnetic EuCd2As2
Authors: Ma Junzhang , Wang Han , Nie Simin , Yi Changjiang , Xu Yuanfeng , Li Hang , Jandke Jasmin , Wulfhekel Wulf , Huang Yaobo , West Damien , Richard Pierre , Chikina Alla , Strocov Vladimir N. , Mesot Joël , Weng Hongming , Zhang Shengbai , Shi Youguo , Qian Tian , Shi Ming , Ding Hong
Published: February 2020

Parity‐time symmetry plays an essential role for the formation of Dirac states in Dirac semimetals. So far, all of the experimentally identified topologically nontrivial Dirac semimetals (DSMs) possess both parity and time reversal symmetry. The realization of magnetic topological DSMs remains a major issue in topological material research. Here, combining angle‐resolved photoemission spectroscopy with density functional theory calculations, it is ascertained that band inversion induces a topologically nontrivial ground state in EuCd2As2. As a result, ideal magnetic Dirac fermions with simplest double cone structure near the Fermi level emerge in the antiferromagnetic (AFM) phase. The magnetic order breaks time reversal symmetry, but preserves inversion symmetry. The double degeneracy of the Dirac bands is protected by a combination of inversion, time‐reversal, and an additional translation operation. Moreover, the calculations show that a deviation of the magnetic moments from the c‐axis leads to the breaking of C3 rotation symmetry, and thus, a small bandgap opens at the Dirac point in the bulk. In this case, the system hosts a novel state containing three different types of topological insulator: axion insulator, AFM topological crystalline insulator (TCI), and higher order topological insulator. The results provide an enlarged platform for the quest of topological Dirac fermions in a magnetic system.
Optimizing Energy Transfer in Nanostructures Enables In Vivo Cancer Lesion Tracking via Near‐Infrared Excited Hypoxia Imaging
Authors: Li Yantao , Liu Jiaming , Wang Zuochao , Jin Jun , Liu Yaling , Chen Chunying , Tang Zhiyong
Published: February 2020

To explore highly sensitive and low‐toxicity techniques for tracking and evaluation of non‐small‐cell lung cancer (NSCLC), one of the most mortal tumors in the world, it is utterly imperative for doctors to select the appropriate treatment strategies. Herein, developing near‐infrared (NIR) excited nanosensors, in which the donor and acceptor pairs within a biological metal–organic framework (bio‐MOF) matrix are precisely controlled to rationalize upconversion Förster resonance energy transfer (FRET), is suggested for detecting the O2 concentration inside tumors with reduced signal disturbance and health detriment. Under NIR excitation, as‐fabricated core/satellite nanosensors exhibit much improved FRET efficiency and reversible hypoxic response with high sensitivity, which are effective both in vitro and in vivo (zebrafish) for cycling normoxia–hypoxia imaging. Significantly, combined with a reliable preclinical genetically engineered murine model, such nanosensors successfully realize tracking of in vivo NSCLC lesions upon clear and gradient hypoxia signals without apparent long‐term biotoxicity, illustrating their exciting potential for efficient NSCLC evaluation and prognosis.
Metallopolymer Organohydrogels with Photo‐Controlled Coordination Crosslinks Work Properly Below 0 °C
Authors: Liu Jiahui , Xie Chaoming , Kretzschmann Annika , Koynov Kaloian , Butt Hans‐Jürgen , Wu Si
Published: February 2020

Controlling the structures and functions of gels is important for both fundamental research and technological applications. Introducing photoresponsive units into gels enables remote control of their properties with light. However, existing gels show photoresponsiveness only at room temperature or elevated temperatures. The development of photoresponsive gels that work below 0 °C can expand their usage in cold environments. Here, photoresponsive metallopolymer organohydrogels that function even at −20 °C are reported. The organohydrogels are prepared using photoresponsive Ru–thioether coordination bonds as reversible crosslinks to form polymer networks. A water/glycerol mixture is used as an anti‐freezing solvent. At −20 °C, the Ru–thioether coordination bonds are dissociated under light irradiation and reformed reversibly in the dark, which result in alternating crosslinking densities in the polymer networks. This process enables inducing reversible gel‐to‐sol transitions, healing damaged gels, controlling the mechanical properties and volumes of the gels, and rewriting microstructures on the gels below 0 °C.
Semiconducting Metal Oxide Photonic Crystal Plasmonic Photocatalysts
Authors: Collins Gillian , Lonergan Alex , McNulty David , Glynn Colm , Buckley Darragh , Hu Changyu , O'Dwyer Colm
Published: February 2020

Plasmonic photocatalysis has facilitated rapid progress in enhancing photocatalytic efficiency under visible light irradiation. Poor visible‐light‐responsive photocatalytic materials and low photocatalytic efficiency remain major challenges. Plasmonic metal–semiconductor heterostructures where both the metal and semiconductor are photosensitive are promising for light harvesting catalysis, as both components can absorb solar light. Efficiency of photon capture can be further improved by structuring the catalyst as a photonic crystal. Here, the synthesis of photonic crystal plasmonic photocatalyst materials using Au nanoparticle‐functionalized inverse opal (IO) photonic crystals is reported. A catalyst prepared using a visible‐light‐responsive semiconductor (V2O5) displayed over an order of magnitude increase in reaction rate under green light excitation (λ = 532 nm) compared to no illumination. The superior performance of Au‐V2O5 IO is attributed to spectral overlap of the electronic bandgap, localized surface plasmon resonance, and incident light source. For the Au‐TiO2 catalyst, despite coupling of the LSPR and excitation source at λ = 532 nm, this is not as effective in enhancing photocatalytic activity compared to carrying out the reaction under broadband visible light, which is attributed to improved photon adsorption in the visible by the presence of a photonic bandgap, and exploiting slow light in the photonic crystal to enhance photon absorption to create this synergistic type of photocatalyst.
Integrating Effect of Surface Modification of Microporous Carbon by Phosphorus/Oxygen as well as the Redox Additive of p‐Aminophenol for High‐Performance Supercapacitors
Authors: Tang Qianfang , Zhong Min , Liu Hao , Chen Xiangying , Zhang Zhongjie , Chen Shuanghong
Published: February 2020

In present work, commercial microporous carbon materials are modified on the surface with phosphorus/oxygen species by using phytic acid as sole dopant, which plays crucial effect on the carbon structure, wettability, electrical conductivity, and capacitive behaviors. It reveals that with increasing the content of heteroatoms, the porosity and contact angle are decreased but the conductivity turns much larger. Furthermore, p‐aminophenol is introduced to serve as redox additive, which can produce more active surface sites by forming hydrogen bond and complexation with the surface functional groups, further providing additional pseudo‐capacitance. As a result, the energy density of carbon sample by phosphorus/oxygen doping in 1 m H2SO4 electrolyte with p‐aminophenol is as high as 9.2 Wh kg−1, which is 2.6 than that of pristine carbon. What is more, in terms of the simple operation and effective performance, the integration of surface modification toward carbon materials and redox additive can be favorable for largely enhancing the supercapacitor performance.
Direct Integration of Few‐Layer MoS2 at Plasmonic Au Nanostructure by Substrate‐Diffusion Delivered Mo
Authors: Ma Rui , Haastrup Mark J. , Wang Zegao , Liu Yumin , Ye Han , Dong Mingdong , Lauritsen Jeppe V. , Sutherland Duncan S.
Published: February 2020

The seamless combination of plasmonic structures with metal oxides and in particular with 2D materials has attracted significant recent interests. Here, a novel approach to grow molybdenum disulfide (MoS2) is presented: an optically active 2D material, directly onto plasmonic nanoscale gold disks via a surface diffusion delivery of Mo from within the nanostructure and a sulfidation process. X‐ray photoelectron spectroscopy and Raman spectroscopy measurements demonstrate the existence and the reaction process of few layered MoS2. Delivery of Mo from within the nanostructure and direct growth of MoS2 has the potential to form better defined metal/MoS2 interfaces compared to exfoliation routes. This facile approach has the potential for application in photodetector or other devices.
A Skin‐Inspired, Interactive, and Flexible Optoelectronic Device with Hydrated Melanin Nanoparticles in a Protein Hydrogel–Elastomer Hybrid
Authors: Gogurla Narendar , Roy Biswajit , Min Kyungtaek , Park Ji‐Yong , Kim Sunghwan
Published: February 2020

Melanin, a biologically occurring pigment featuring broadband optical absorption, ion‐binding affinity including antioxidative and radical‐scavenging properties, and hydration‐dependent electrical conductivity is an ideal natural semiconducting material for interfacing electronics with biological systems. Here, a skin‐mimicking optoelectronic device with a melanin nanoparticle (MNP) dispersion in a protein hydrogel–elastomer hybrid (a mimic of epidermis/dermis layers with melanin) and its application as a dopamine sensor and a UV index meter are reported. MNPs dispersed in water are placed in the elastomer reservoir with integrated silver nanowire electrodes and a transparent silk hydrogel window cover; they exhibit n‐type semiconducting behavior with increased conductivities compared with those of dehydrated MNPs. Enhanced generation of free radicals by light illumination results in an increase of the electrical conductivity. In addition, the artificial optoelectronic skin interacts with its environment through the silk hydrogel window. Applications of the device, including its use as a dopamine sensor and a UV index meter to detect dopamine and UV light passing through the window, are demonstrated. The sensitivity of the dopamine sensor is enhanced by the light illumination.
A Large‐Area, Stretchable, Textile‐Based Tactile Sensor
Authors: Zhang Youzhi , Lin Zhengkang , Huang Xingping , You Xiaojun , Ye Jinhua , Wu Haibin
Published: February 2020

A tactile sensor is a necessary means for intelligent equipment to acquire external environment information and improve the performance of human–robot interaction. Although high‐performance tactile sensor array is widely studied, the large number of wires required to transmit data from numerous arrays is still a major obstacle in large‐area application. In this study, a large‐area, low‐cost, stretchable, textile‐based tactile sensor, which is sensitive for contact position, is proposed. The sensor has a simple three‐layer structure and four external wires due to the use of a novel double‐faced effect functional knitted textile with “self‐uniformity” characteristic. The porous polyurethane foam with a large pore size is first reported as touch switch material. It not only has excellent touch switch function, but also makes the sensor have a soft and elastic touch and good impact buffering. In addition, the application of radial basis function neural network makes the sensor have self‐learning “intelligence,” which makes the sensor flexibly and quickly arrange even on the surface of a complex 3D object. Finally, the potential applications of the sensor are demonstrated. This study shows that the sensor has great potential in the fields of wearable devices, robot interaction control, and human–computer interface.
Synergistic Resistance Modulation toward Ultrahighly Sensitive Piezoresistive Pressure Sensors
Authors: Yuan Liqian , Wang Zhongwu , Li Hongwei , Huang Yinan , Wang Shuguang , Gong Xue , Tan Ziting , Hu Yongxu , Chen Xiaosong , Li Jie , Lin Hongzhen , Li Liqiang , Hu Wenping
Published: February 2020

Improvement of sensitivity of electrical piezoresistive sensors is critical for high‐precision and ultrasensitive detection, which mainly depends on the modulation ability of total resistance of sensor under applied pressure. However, in most of the reported sensor devices, the contact resistance and body resistance (the key parts of total resistance of sensor) generally cannot be modulated simultaneously, which results in the limited sensitivity. In this work, an ultrahighly sensitive piezoresistive pressure sensor with an exquisitely designed structure is demonstrated, providing an uncomparable advantage of synergistic modulation of contact resistance and body resistance under applied pressure. As a result, the sensor shows excellent sensing performance, with the highest sensitivity up to 11 668.6 kPa−1, the detection limit as low as 0.425 Pa, and the great stability over 20 000 cycle measurements. In respect of practical application, the high sensitivity endows the sensor with high‐precision recognition ability for detecting the weak pressure signals such as sound wave of ringtone and fluctuation of breath or pulse. These results suggest the synergistic resistance modulation to be an effective method toward piezoresistive pressure sensors with ultrahigh sensitivity and offer a new strategy for the achievement of high‐performance pressure sensors.
Development of a High‐Performance Handheld Triboelectric Nanogenerator with a Lightweight Power Transmission Unit
Authors: Choi Seonbeen , Cho Sumin , Yun Yeongcheol , Jang Sunmin , Choi Jun Hyuk , Ra Yoonsang , La Moonwoo , Park Sung Jea , Choi Dongwhi
Published: February 2020

A triboelectric nanogenerator (TENG) is a promising energy harvester that exploits the combination of contact electrification between two different material surfaces and electrical induction. In this study, a handheld‐TENG (HH‐TENG) is developed to harvest biomechanical energy effectively, especially energy generated from finger motions, which is one of the most common body movements involving lots of energy. To enhance the electrical output performance of the device while minimizing the inconvenience caused by carrying it, a rationally designed lightweight power transmission unit is adopted. As a result, an extremely high number of output cycles with high specific peak power (greater than 10 µW g–1) can be achieved in a single operation of the HH‐TENG. Although the proposed HH‐TENG weighs less than 70 g, the developed HH‐TENG can be connected with commercially available electric circuits such as an AC‐DC converter to generate not only reliable and continuous DC voltage to power portable electronics, but also further boosted open‐circuit voltage greater than 2.5 kV, which is sufficient to generate microplasma in a room environment. Adoption of a lightweight power transmission unit with the TENG can be considered as an effective strategy to significantly enhance the specific power, which advances the TENG toward practical implementation.
Pick and Place Distributed Feedback Lasers Using Organic Single Crystals
Authors: Ma Suqian , Wei Mengjie , Rajendran Sai Kiran , Karl Markus , Xu Bin , Gather Malte C. , Tian Wenjing , Turnbull Graham A. , Samuel Ifor D. W.
Published: February 2020

Organic single crystals are of interest for optoelectronic applications due to their highly ordered molecular stacking and small defect concentration, giving the possibility of high mobility and luminescence efficiency. To achieve lasing in large flat single crystals, a simple “pick and place” method of mounting organic single crystals onto distributed feedback gratings is demonstrated. Efficient lasing is achieved with three kinds of active organic single crystals, indicating the potential for broad application of the method for making single crystal lasers using distributed feedback gratings. Detailed investigations of the anisotropic refractive index and waveguide simulations further confirm that distributed feedback can provide efficient ways of fabricating organic single crystal lasers.
Boosted UV Photodetection Performance in Chemically Etched Amorphous Ga2O3 Thin‐Film Transistors
Authors: Han Zuyin , Liang Huili , Huo Wenxing , Zhu Xiaoshan , Du Xiaolong , Mei Zengxia
Published: February 2020

A three‐terminal thin‐film transistor (TFT) architecture is essential for photodetectors to reach a good balance between high responsivity and fast response speed. Bottom‐gate amorphous Ga2O3 (a‐Ga2O3) TFTs are fabricated to boost their UV photodetection properties. During the device fabrication process, a simple chemical‐etching solution with the advantages of easy operation, low cost, and compatibility with traditional lithography process, is developed to selectively etch a‐Ga2O3 films. The a‐Ga2O3 channel etched device on Si manifests an effective suppression of the commonly observed gate leakage current. Meanwhile, a patterned a‐Ga2O3 TFT on quartz shows an excellent n‐type TFT performance with an on/off ratio as high as ≈107. It is further applied as a phototransistor, to diminish the persistent photoconductivity (PPC) effect while keeping a high responsivity (R) as well. Under the 254 nm UV illumination, the a‐Ga2O3 phototransistor demonstrates a high light‐to‐dark ratio of 5 × 107, a high responsivity of 5.67 × 103 A W−1, and a high detectivity of 1.87 × 1015 Jones. Remarkably, the PPC phenomenon in a‐Ga2O3 UV phototransistors is effectively suppressed by applying a positive gate pulse, which greatly shortens the decay time to 5 ms and offers a‐Ga2O3 possible inroads into imaging applications.
Highly Stable All‐Inorganic Perovskite Quantum Dots Using a ZnX2‐Trioctylphosphine‐Oxide: Application for High‐Performance Full‐Color Light‐Emitting Diode
Authors: Baek Seungmin , Kang Seokwoo , Son Chaeyeon , Shin So Jeong , Kim Jong H. , Park Jongwook , Kim Sang‐Wook
Published: February 2020

Perovskite is a very promising material that is being extensively studied at the bulk and nanosize scales because it has outstanding optical properties, including high quantum efficiency and narrow emission spectra. However, perovskite has stability issues related to heat, air, and light. To overcome these, highly stable perovskite quantum dots (PeQDs) are developed using excess Zn precursor and trioctylphosphine‐oxide (TOPO). In particular, it is clarified that Zn and TOPO are combined and these complexes are attached to the surface of the PeQDs through 31P NMR. They not only have high quantum efficiency and sharp full width at half maximum values (15–30 nm) but also have improved long‐term stability at high temperature. Additionally, XPS measurements are conducted for a detailed surface analysis of PeQDs, finding that the TOPO‐Zn complex effectively decrease PbO bonding in the lattice. Perovskite full‐color electroluminescence (EL) devices are fabricated using PeQDs and 9,9‐bis[4‐[(4‐ethenylphenyl)methoxy]phenyl]‐N2,N7‐di‐1‐naphthalenyl‐N2,N7‐diphenyl‐9H‐fluorene‐2,7‐diamine (VB‐FNPD) as a new cross‐linkable hole transporting material. The VB‐FNPD has a high‐hole carrier mobility compared to the PVK as conventional hole‐transporting layer. As a result of EL performance, they have high EQE (%) and current efficiency (Cd A−1) of (7.12%, 9.93 Cd A−1) for red, (6.06%, 32.5 Cd A−1) for green, and (0.56%, 0.88 Cd A−1) for blue‐emitting devices, respectively.
Self‐Powered Humidity Sensor Using Chitosan‐Based Plasmonic Metal–Hydrogel–Metal Filters
Authors: Jang Jaehyuck , Kang Kyungnam , Raeis‐Hosseini Niloufar , Ismukhanova Aizhan , Jeong Heonyeong , Jung Chunghwan , Kim Byeongsu , Lee Jung‐Yong , Park Inkyu , Rho Junsuk
Published: February 2020

A tunable Fabry–Pérot resonator is realized using metal–insulator–metal structure, in which the insulator is chitosan hydrogel. The chitosan swells in response to changes in relative humidity; this change affects transmissive structural color of the multilayer structure. This tunable resonator is utilized for a humidity sensor combined with a photovoltaic cell. The change in current through the photovoltaic cell provides rapid precise measurement of relative humidity, and the change in color of the multilayer provides an approximate, remotely‐readable estimate. The response requires no power, so the device has numerous sensing applications.
An Ultraviolet–Visible and Near‐Infrared‐Responded Broadband NIR Phosphor and Its NIR Spectroscopy Application
Authors: Zhou Xufeng , Geng Wanying , Li Junyi , Wang Yichao , Ding Jianyan , Wang Yuhua
Published: February 2020

High‐radiance near‐infrared (NIR) phosphor‐converted light‐emitting diodes (pc‐LEDs) are demanded for wearable biosensing devices and the properties of these pc‐LEDs are highly dependent on the performance of the NIR phosphor. An ultraviolet–visible and NIR‐responded broadband NIR NaScGe2O6:Cr3+ phosphor is reported. Under 490 nm excitation, NaScGe2O6:Cr3+ shows broad emission band from 700 to 1250 nm, which covers the first and second NIR windows. An NIR pc‐LED with radiant flux of 12.07 mW@350 mA is realized based on NaScGe2O6:Cr3+ and 450 nm blue LED chip. The ability of high‐power NIR light of the NIR pc‐LED to penetrate human tissues is observed successfully. Additionally, in NaScGe2O6:Cr3+, the luminescence performance of Cr3+ under 808 nm laser excitation is achieved for the first time.
Optical Functional Units in Zero‐Dimensional Metal Halides as a Paradigm of Tunable Photoluminescence and Multicomponent Chromophores
Authors: Li Mingze , Molokeev Maxim S. , Zhao Jing , Xia Zhiguo
Published: February 2020

Zero‐dimensional (0D) organic–inorganic hybrid luminescent metal halides have many promising optoelectronic applications; however, the single building unit in the 0D framework restricts their multimode optical control and photoluminescence tuning. Thus, it remains urgent but challenging to rationally design distinct anionic polyhedral with different optical functions and further expand this family by an equivalent cation substitution and halogen replacement. Herein, (C9NH20)9[Pb3X11](MX4)2 (X = Br and Cl, M = Mn, Fe, Co, Ni, Cu, and Zn) is successfully synthesized verifying the rationality of the design philosophy, and the optical characterizations demonstrate the effects of X‐position anions and M‐position cations on luminescence process. Intriguingly, both [Pb3X11]5− and [MX4]2− perform as inorganic building units in this 0D system and optically active centers, in which the former leads to high‐efficiency broad‐band yellow/green emission originating from self‐trapped excitons and the as‐observed multicomponent chromophores are derived from the absorption of the latter in the visible light region. The present work highlights the importance of different optical functional units showing synergistic effects on the physical properties and inspires future studies to explore multifunctional application of 0D luminescent metal halides.
Dissolving Microneedles Loading TPGS Biphasic Functionalized PLGA Nanoparticles for Efficient Chemo‐Photothermal Combined Therapy of Melanoma
Authors: Peng Tingting , Huang Yao , Feng Xiaoqian , Zhu Chune , Ma Xiangyu , Wang Xinyi , Bai Xuequn , Pan Xin , Wu Chuanbin
Published: February 2020

The poly (lactic‐co‐glycolic acid) nanoparticle (PLGA NP) has been widely used in the biomedical field. However, it is insensitive to degradation upon laser irradiation, resulting in a limited increase in drug release, which compromises the therapeutic efficacy. To actively promote drug release, the biphasic α‐tocopheryl succinate (TPGS) functionalized PLGA NPs (PTNPs) are developed by introducing TPGS into the aqueous and organic phase to generate pores in the PLGA core during preparation. Paclitaxel and indocyanine green are encapsulated in the PTNPs to realize chemo‐photothermal combined therapy, and PTNPs are delivered through dissolving microneedles (DMNs) for local treatment in melanoma. PTNPs show enhanced drug release and improved cytotoxicity due to their greater ability in inhibiting cell microtubule depolymerization. In vivo tumor suppression investigation and ki‐67 immunohistochemical staining of tumor tissue further show the superiority of PTNPs loaded DMNs against tumor growth, and photothermal therapy synergistically enhances the chemotherapeutic effect of PTNPs. Moreover, the living imaging of mice demonstrates that the drug is successfully retained in the tumor tissue to avoid it entering into the circulation and producing adverse effects. Therefore, the PTNPs loaded DMNs show a favorable prospect in the treatment of superficial tumor.
A New Strategy for Detecting Plant Hormone Ethylene Using Oxide Semiconductor Chemiresistors: Exceptional Gas Selectivity and Response Tailored by Nanoscale Cr2O3 Catalytic Overlayer
Authors: Jeong Seong‐Yong , Moon Young Kook , Kim Tae‐Hyung , Park Sei‐Woong , Kim Ki Beom , Kang Yun Chan , Lee Jong‐Heun
Published: February 2020

A highly selective and sensitive detection of the plant hormone ethylene, particularly at low concentrations, is essential for controlling the growth, development, and senescence of plants, as well as for ripening of fruits. However, this remains challenging because of the non‐polarity and low reactivity of ethylene. Herein, a strategy for detecting ethylene at a sub‐ppm‐level is proposed by using oxide semiconductor chemiresistors with a nanoscale oxide catalytic overlayer. The SnO2 sensor coated with the nanoscale catalytic Cr2O3 overlayer exhibits rapid sensing kinetics, good stability, and an unprecedentedly high ethylene selectivity with exceptional gas response (Ra/Rg − 1, where Ra represents the resistance in air and Rg represents the resistance in gas) of 16.8 at an ethylene concentration of 2.5 ppm at 350 °C. The sensing mechanism underlying the ultraselective and highly sensitive ethylene detection in the unique bilayer sensor is systematically investigated with regard to the location, configuration, and thickness of the catalytic Cr2O3 overlayer. The mechanism involves the effective catalytic oxidation of interfering gases into less‐ or non‐reactive species, without limiting the analyte gas transport. The sensor exhibits a promising potential for achieving a precise quantitative assessment of the ripening of five different fruits.
Investigating the Effects of Chemical Gradients on Performance and Reliability within Perovskite Solar Cells with TOF‐SIMS
Authors: Harvey Steven P. , Messinger Jonah , Zhu Kai , Luther Joseph M. , Berry Joseph J.
Published: February 2020

Time‐of‐flight secondary‐ion mass spectrometry (TOF‐SIMS), a powerful analytical technique sensitive to all components of perovskite solar cell (PSC) materials, can differentiate between the various organic species within a PSC absorber or a complete device stack. The ability to probe chemical gradients through the depth of a device (both organic and inorganic), with down to 100 nm lateral resolution, can lead to unique insights into the relationships between chemistry in the absorber bulk, at grain boundaries, and at interfaces as well as how they relate to changes in performance and/or stability. In this review, the technique is described; then, from the literature, several examples of how TOF‐SIMS have been used to provide unique insight into PSC absorbers and devices are covered. Finally, the common artifacts that can be introduced if the data are improperly collected, as well as methods to mitigate these artifacts are discussed.
Damage to the primary root in response to cattle slurry placed near seed may compromise early growth of corn
Authors: Pedersen Ingeborg Frøsig , Sørensen Peter , Baral Khagendra R. , Rubæk Gitte Holton
Published: February 2020

Placement of cattle slurry below the row could potentially replace mineral phosphorus (P) starter fertilizer in corn (Zea mays) production, but a concentrated slurry layer near the seed may also restrict root growth. This study was designed to assess how the distance between seed and layer‐banded slurry affected initial growth of corn. In a pot experiment with corn on a coarse sandy soil, nitrogen‐labeled (15N) cattle slurry was placed 1.5, 5, 8.5, or 12 cm below the seed, and responses on early root growth, shoot biomass, and nutrient uptake were studied. Soil chemical properties near the slurry band were determined in unplanted soil. Placement of slurry 1.5 cm below the seed damaged the primary root, which subsequently reduced shoot biomass and N uptake. Shoot P uptake remained unaffected by slurry placement depth. The15N assay revealed that plants were able to take up N from the slurry band despite damage to the primary root. The shoot biomass was higher in the inorganic N and P treatment than in the slurry treatments. Within a few centimeters above the slurry band, the soil was characterized by high moisture and high concentrations of ammonium and nitrite 21 and 35 d after slurry application, which may have caused the damages of the primary root. We conclude that placement of slurry near the seed can damage the primary root of corn. To prevent root injuries, banded slurry should be placed at least 5 cm below the seed.
Effective weed suppression in dual‐use intermediate wheatgrass systems
Authors: Zimbric Joseph W. , Stoltenberg David E. , Picasso Valentin D.
Published: February 2020

Intermediate wheatgrass [IWG; Thinopyrum intermedium (Host) Barkworth & D.R. Dewey] is a cool‐season perennial forage grass bred for higher seed yield. It is the first perennial grain crop in the United States, commercialized as Kernza since 2015. Managing IWG as a dual‐use grain and forage crop could provide several ecosystem services including conserving soil and clean water while increasing economic income to growers. However, little is known about the weed management risks associated with IWG. Therefore, we studied weed community composition, biomass, IWG grain, and aboveground biomass in a factorial experiment with two weed management treatments, two nitrogen fertilization rates, and four forage harvest schedules (no harvest, summer only, summer + fall, and spring + summer + fall). Over three production years, weed biomass decreased by 88% regardless of treatment, and the weed community composition changed from predominantly winter annual to perennial species. In the second and third production years the weed community composition remained relatively stable. Grain yield was 16% greater with 135 kg N ha−1 than 90 kg N ha−1 but was not affected by in‐season forage harvest or weed management treatments in the second and third years. Grain yield decreased from 763 to 371 kg ha−1 over three years, while aboveground biomass remained stable. Weed presence did not affect yields in second and third years. Dual‐use IWG cropping systems effectively suppressed weeds and IWG is a promising grain crop alternative for farmers interested in diversifying their cropping systems under similar conditions.
Cultivation of native plants for seed and biomass yield
Authors: Freund Saxhaug Katrina , Jungers Jacob M. , Hegeman Adrian D. , Wyse Donald L. , Sheaffer Craig C.
Published: February 2020

Establishing native perennial plants on the agricultural landscape can improve ecosystem services and provide marketable products, such as seed for restoration plantings and biomass for renewable energy. Native perennials of economic and ecological interest should be examined in different planting configurations over time to determine their suitability for sustained production. Canada milk vetch (Astragalus canadensisL.), purple coneflower (Echinacea purpureaL.), and showy tick trefoil (Desmodium canadenseL.) were established at two locations in Minnesota to evaluate seed and vegetative biomass yields. These forbs were established in six different agronomic designs: three strip designs (one‐row, three‐rows, and six‐rows) and three community designs (monoculture, low‐richness polyculture, and high‐richness polyculture). Seed yield averaged 2995, 950, and 1157 kg ha−1for Canada milk vetch, purple coneflower, and showy tick trefoil in the first year and declined for all species over time. Biomass yields averaged 6743, 2725, and 2869 kg ha−1in the first year for Canada milk vetch, purple coneflower, and showy tick trefoil, respectively. Canada milk vetch biomass yields declined by 98% over time, and showy tick trefoil biomass yields increased by 40%. Seed and biomass yields were the lowest in one‐row strip design and greatest in the community designs, with little difference between monocultures and polycultures. Results suggest that production is maximized in community designs and that purple coneflower and showy tick trefoil have the potential for multiyear yields.
Substitutability of Freshwater and Non‐Freshwater Sources in Irrigation: an Econometric Analysis
Authors: Finkelshtain Israel , Kan Iddo , Rapaport‐Rom Mickey
Published: February 2020

Population growth is increasing the scarcity of freshwater for irrigation and accelerating its replacement with non‐freshwater sources such as treated wastewater and brackish water. Although these substitutes may be less productive agronomically, their supply is usually more stable. We develop a structural econometric framework to assess the substitution between fresh‐ and non‐fresh water as it is inferred from water‐use decisions of farmers under increasing block‐rate water pricing. We employ the model to village‐level panel data from Israel, in which 50% of the freshwater allotments were replaced during the 1990–2010 period by treated‐wastewater quotas, using a non‐freshwater/freshwater volumetric exchange rate of 1.2. Based on our estimation results, the hypothesis that the marginal rate of substitution between the two water sources is equal to one cannot be rejected. Simulations suggest that the Israeli quota‐exchange policy has increased both agricultural production value and farming profits.
Fine‐scale habitat heterogeneity and vole runways influence seed dispersal in Plagiobothrys nothofulvus
Authors: Grasty Monica R. , Thompson Pamela G. , Hendrickson Elizabeth C. , Pheil Avery E. , Cruzan Mitchell B.
Published: February 2020

Premise

Seed dispersal allows plants to colonize new sites and contributes to gene flow among populations. Despite its fundamental importance to ecological and evolutionary processes, our understanding of seed dispersal is limited due to the difficulty of directly observing dispersal events. This is particularly true for the majority of plant species that are considered to have gravity as their primary dispersal mechanism. The potential for long‐distance movement of gravity‐dispersed seeds by secondary dispersal vectors is rarely evaluated.

Methods

We employ whole‐genome assays of maternally inherited cpDNA in Plagiobothrys nothofulvus to resolve patterns of genetic variation due to effective (realized) seed dispersal within a 16 hectare prairie that is characterized by a mosaic of habitat types. We evaluate the effects of microgeographic landscape features extracted from micro‐UAV aerial surveys on patterns of seed dispersal using landscape genetics methods.

Results

We found evidence of high resistance to seed‐mediated gene flow (effective dispersal) within patches of Plagiobothrys nothofulvus, and strong genetic structure over distances of less than 20 m. Geographic distance was a poor predictor of dispersal distance, while landscape features had stronger influences on patterns of dispersal (distance and direction of seed movement). Patterns of dispersal were best predicted by the combined distribution of flower patches, habitat type, and the network of vole runways, with the latter explaining the largest proportion of variation in the model.

Conclusions

Our results suggest that primary dispersal occurs mostly within microhabitats and infrequent secondary dispersal may occur over longer distances due to the activity of small mammals and other vertebrates.
Improved Acid Resistance of a Metal–Organic Cage Enables Cargo Release and Exchange between Hosts
Authors: Xu Lin , Zhang Dawei , Ronson Tanya K. , Nitschke Jonathan R.
Published: February 2020

The use of di(2‐pyridyl)ketone in subcomponent self‐assembly is introduced. When combined with a flexible triamine and zinc bis(trifluoromethanesulfonyl)imide, this ketone formed a new Zn4L4 tetrahedron 1 bearing twelve uncoordinated pyridyl units around its metal‐ion vertices. The acid stability of 1 was found to be greater than that of the analogous tetrahedron 2 built from 2‐formylpyridine. Intriguingly, the peripheral presence of additional pyridine rings in 1 resulted in distinct guest binding behavior from that of 2, affecting guest scope as well as binding affinities. The different stabilities and guest affinities of capsules 1 and 2 enabled the design of systems whereby different cargoes could be moved between cages using acid and base as chemical stimuli.
Iridium‐Catalyzed Enantioselective Intermolecular Indole C2‐Allylation
Authors: Rossi‐Ashton James A. , Clarke Aimee K. , Donald James R. , Zheng Chao , Taylor Richard J. K. , Unsworth William P. , You Shu‐Li
Published: February 2020

The enantioselective intermolecular C2‐allylation of 3‐substituted indoles is reported for the first time. This directing group‐free approach relies on a chiral Ir‐(P, olefin) complex and Mg(ClO4)2 Lewis acid catalyst system to promote allylic substitution, providing the C2‐allylated products in typically high yields (40–99 %) and enantioselectivities (83–99 % ee) with excellent regiocontrol. Experimental studies and DFT calculations suggest that the reaction proceeds via direct C2‐allylation, rather than C3‐allylation followed by in situ migration. Steric congestion at the indole‐C3 position and improved π–π stacking interactions have been identified as major contributors to the C2‐selectivity.
A Light‐Responsive Metal–Organic Framework Hybrid Membrane with High On/Off Photoswitchable Proton Conductivity
Authors: Liang Hong‐Qing , Guo Yi , Shi Yanshu , Peng Xinsheng , Liang Bin , Chen Banglin
Published: February 2020

Mimicking biological proton pumps to achieve stimuli‐responsive protonic solids has long been of great interest for their diverse applications in fuel cells, chemical sensors, and bio‐electronic devices. Now, dynamic light‐responsive metal–organic framework hybrid membranes can be obtained by in situ encapsulation of photoactive molecules (sulfonated spiropyran, SSP), as the molecular valve, into the cavities of the host ZIF‐8. The configuration of SSP can be changed and switched reversibly in response to light, generating different mobile acidic protons and thus high on/off photoswitchable proton conductivity in the hybrid membranes and device. This device exhibits a high proton conductivity, fast response time, and extremely large on/off ratio upon visible‐light irradiation. This approach might provide a platform for creating emerging smart protonic solids with potential applications in the remote‐controllable chemical sensors or proton‐conducting field‐effect transistors.
Interfacial Polymerization: From Chemistry to Functional Materials
Authors: Zhang Feilong , Fan Jun‐bing , Wang Shutao
Published: February 2020

Interfacial polymerization, where a chemical reaction is confined at the liquid–liquid or liquid–air interface, exhibits a strong advantage for the controllable fabrication of films, capsules, and fibers for use as separation membranes and electrode materials. Recent developments in technology and polymer chemistry have brought new vigor to interfacial polymerization. Here, we consider the history of interfacial polymerization in terms of the polymerization types: interfacial polycondensation, interfacial polyaddition, interfacial oxidative polymerization, interfacial polycoordination, interfacial supramolecular polymerization, and some others. The accordingly emerging functional materials are highlighted, as well as the challenges and opportunities brought by new technologies for interfacial polymerization. Interfacial polymerization will no doubt keep on developing and producing a series of fascinating functional materials.
Indirect and Direct Grafting of Transition Metals to Siliconoids
Authors: Poitiers Nadine E. , Giarrana Luisa , Leszczyńska Kinga I. , Huch Volker , Zimmer Michael , Scheschkewitz David
Published: February 2020

Unsaturated charge‐neutral silicon clusters (siliconoids) are important as gas‐phase intermediates between molecules and the elemental bulk. With stable zirconocene‐ and hafnocene‐substituted derivatives, we here report the first examples containing directly bonded transition‐metal fragments that are readily accessible from the ligato‐lithiated Si6 siliconoid (1Li) and Cp2MCl2 (M=Zr, Hf). Charge‐neutral siliconoid ligands with pending tetrylene functionality were prepared by the reaction of amidinato chloro tetrylenes [PhC(NtBu)2]ECl (E=Si, Ge, Sn) with 1Li, thus confirming the principal compatibility of such low‐valent functionalities with the unsaturated Si6 cluster scaffold. The pronounced donor properties of the tetrylene/siliconoid hybrids allow for their coordination to the Fe(CO)4 fragment.