bluuebunny/crossref_metadata_2025_split huggingface dataset:
Priming by Arbuscular Mycorrhizal Fungi of Plant Antioxidant Enzyme Production: A Meta‐analysis
Authors: Lokhandwala Ami , Hoeksema Jason D. 
Published: November 2019

Abstract
Priming of antioxidant enzyme production of plants, which can act as a defence against pathogens and other stresses, is an under‐appreciated benefit often provided by arbuscular mycorrhizal (AM) fungi. Although numerous experiments have demonstrated this phenomenon, this literature has not been synthesised, and we understand little about the factors that may drive variation in the magnitude of this priming phenomenon. We gathered data from 81 original publications in which antioxidant enzyme production of plants was measured in the presence and absence of AM fungi, including factors that varied among studies, such as the identity of plants and fungi, number of species and genera of fungi, the presence and type of plant stress, the particular enzyme measured, and the plant tissues sampled. We used these data to estimate the average magnitude of the priming effect, and to ask whether these study‐level variables explained variation in the magnitude of priming. We found that AM fungi increased plant production of antioxidant enzymes by approximately 16%, regardless of whether the plants were under stress. The identity of plants and fungi, number of species and genera of fungi, and the type of stress did not explain variability in the degree of priming. In the absence of stress, priming was higher for peroxidase enzymes than other enzyme classes, and plant root tissues exhibited greater priming responses than other plant tissues. Our best meta‐analysis models had substantial unexplained heterogeneity in effect size among studies, suggesting that additional factors not included in our analyses could help explain variation in priming. Overall, the degree of priming observed here suggests the potential for mycorrhiza‐induced resistance to diseases to have broader application, including for the improvement of sustainable agriculture.
The research of superheated steam temperature control based on generalized predictive control algorithm and adaptive forgetting factor
Authors: Jiang Cheng , Qian Hong , Pan Yuekai , Chai Tingting 
Published: November 2019

SummaryThe superheated steam temperature system of the thermal power plant has the characteristics of large inertia, nonlinearity, and strong time variation, which make it difficult to be controlled. To address these problems, this paper proposes a generalized predictive control algorithm with an adaptive forgetting factor. First, based on a fuzzy algorithm and a recursive least squares algorithm, the controlled object's model can be quickly and accurately obtained with the adaptive forgetting factor in real time. It overcomes the nonlinear and time‐varying problems of the controlled object in the control progress. Meanwhile, it also solves the problem of data saturation and the weight assignment of the “new and old” data during online identification. Second, an adaptive generalized predictive controller algorithm has been developed with the controlled object. It solves the large inertia problem of the controlled object. Finally, through establishing simulation model of the superheated steam temperature system and simulating, the results show that the proposed method has better control performance, antidisturbance ability, adaptability, and robustness. Moreover, it has a certain reference significance for the design of a practical control system.
Machine Learning Approaches for Thermoelectric Materials Research
Authors: Wang Tian , Zhang Cheng , Snoussi Hichem , Zhang Gang 
Published: November 2019

AbstractThermoelectric (TE) materials provide a solid‐state solution in waste heat recovery and refrigeration. During the past few decades, considerable effort has been devoted towards improving the performance of TE materials, which requires the optimization of multiple interrelated properties. A fundamental understanding of the interaction processes between the various energy carriers, such as electrons and phonons, is critical for advances in the development of TE materials. However, this understanding remains challenging primarily due to the inaccessibility of time scales using standard atomistic simulations. Machine learning methods, well known for their data‐analysis capability, have been successfully applied in research on TE materials in recent years. Here, an overview of the machine learning methods used in thermoelectric studies is provided, with the role that each machine learning method plays being systematically discussed. Furthermore, to date, the scale of thermoelectric‐related databases is much smaller than those in other fields, such as e‐commerce, image identification, and speech recognition. To overcome this limitation, possible strategies to utilize small databases in promoting materials science are also discussed. Finally, a brief conclusion and outlook are presented.
Addressing the Reliability and Electron Transport Kinetics in Halide Perovskite Film via Pulsed Laser Engineering
Authors: Song Chunpeng , Tong Lei , Liu Feng , Ye Lei , Cheng Gary J. 
Published: November 2019

AbstractThe long‐term performance and stability of perovskites are adversely affected by their porous microstructure, tensile residual stress, and electron transport kinetics. Here, a high‐speed pulsed laser processing technique is implemented to produce beneficial structural changes in organic–inorganic halide perovskites, including pore‐free, crystalline structure, reduced defects, and tensile residual stress. Moreover, halide perovskite films can be converted from p‐type to n‐type semiconductor, which originates from crystal structure changes, giving rise to carrier dynamic changes. Comparing with traditional thermal annealing, residual tensile stress of perovskite thin film decreases by 40% after pulse laser processing, which significantly increases its stability. Pulse‐laser‐induced thermomechanical shock momentum can create pore‐free perovskite thin films, contributing to much better reliability. Under humidity of 80% at room temperature for 500 h, the decomposition rate is reduced by more than two times, comparing thin films after pulsed laser processing with conventional thermal annealing. The thermal decomposition temperature of pulse‐laser‐processed perovskite thin film raises by 20 to about 220 °C. Pulse laser processing technique provides a scalable technique to tailor the structures in perovskite films with both temperature and loading control, further facilitates the design of perovskite‐based devices for service under harsh conditions, and also contributes to high‐performance optoelectronic applications.
Chemiresistors for the Real‐Time Wireless Detection of Anions
Authors: Choi Seon‐Jin , Yoon Bora , Ray Jason D. , Netchaev Anton , Moores Lee C. , Swager Timothy M. 
Published: November 2019

AbstractReported is an electrical transduction platform for real‐time wireless anion sensing using single‐walled carbon nanotubes (SWCNTs) noncovalently functionalized with squaramide‐based anion binding selectors. Systematically studied are anion‐binding properties and efficiency of the electrical transduction of the functionalized SWCNT composites using the squaramide‐based selectors with two similar electron‐withdrawing groups, 3,5‐bis(trifluoromethyl)benzyl (1) and 3,5‐bis(trifluoromethyl)phenyl (2), which induce hydrogen‐bonding interaction with anions and deprotonation of a squaramide N–H proton upon addition of acetate (AcO−), respectively. Charge transduction occurs with AcO− as a result of charge transfer from the deprotonated selector 2, whereas less sensitive transduction is observed with selector 1 via hydrogen‐bonding interaction. These results provide guidelines to efficiently transduce the chemical interaction between selectors and anions to create resistive transduction with functionalized SWCNTs. Electron‐withdrawing groups adjacent to the squaramide as well as proximate cationic pyridyl groups, enhance the anion binding affinity and also lower the selector's pKa. The chemiresistive sensor arrays are readily integrated with a wireless sensing module and demonstrated real‐time sensing of multiple anions with a smartphone readout.
Energy Transfer to a Stable Donor Suppresses Degradation in Organic Solar Cells
Authors: Weu Andreas , Kumar Rhea , Butscher Julian F. , Lami Vincent , Paulus Fabian , Bakulin Artem A. , Yaynzof Yana 
Published: November 2019

AbstractDespite many advances toward improving the stability of organic photovoltaic devices, environmental degradation under ambient conditions remains a challenging obstacle for future application. Particularly conventional systems employing fullerene derivatives are prone to oxidize under illumination, limiting their applicability. Here, the environmental stability of the small molecule donor DRCN5T together with the fullerene acceptor PC70BM is reported. It is found that this system exhibits exceptional device stability, mainly due to almost constant short‐circuit current. By employing ultrafast femtosecond transient absorption spectroscopy, this remarkable stability is attributed to two separate mechanisms: 1) DRCN5T exhibits high intrinsic resistance toward external factors, showing no signs of deterioration. 2) The highly sensitive PC70BM is stabilized against degradation by the presence of DRCN5T through ultrafast, long‐range energy transfer to the donor, rapidly quenching the fullerene excited states which are otherwise precursors for chemical oxidation. It is proposed that this photoprotective mechanism be utilized to improve the device stability of other systems, including nonfullerene acceptors and ternary blends.
The Impact of Stoichiometry on the Photophysical Properties of Ruddlesden–Popper Perovskites
Authors: Duim Herman , Adjokatse Sampson , Kahmann Simon , ten Brink Gert H. , Loi Maria Antonietta 
Published: November 2019

Abstract2D Ruddlesden–Popper perovskites are interesting for a variety of applications owing to their tunable optical properties and their excellent ambient stability. As these materials are processable from solution, they hold the promise of procuring flexible and cost‐effective films through large‐scale fabrication techniques. However, such solution‐based deposition techniques often induce large degrees of heterogeneity due to poorly controlled crystallization. The microscopic properties of films of (PEA)2PbI4 cast from precursor solutions of different stoichiometry are therefore investigated. The stoichiometry of the precursor solution is found to have a large impact on the crystallinity, morphology, and optical properties of the resulting thin films. Even for films cast from stoichiometric precursors, differences in photoluminescence intensities occur on a subgranular level. The heterogeneity in these films is found to be thermally activated with an activation energy of 0.4 eV for the emergence of local variations in nonradiative recombination rates. The spatial variation in the distribution of trap states is attributed to local fluctuations in the stoichiometry. In line with this, the surface can successfully be passivated by providing an excess of phenylethylammonium iodide (PEAI) to an as‐cast film, enhancing the photoluminescence by as much as 85% without significantly altering the film's morphology.
Scalable Flexible Hybrid Membranes with Photonic Structures for Daytime Radiative Cooling
Authors: Wang Xin , Liu Xianghui , Li Zhenyang , Zhang Haiwen , Yang Zhiwei , Zhou Han , Fan Tongxiang 
Published: November 2019

AbstractPassive radiative cooling technology can cool down an object by reflecting solar light and radiating heat simultaneously. However, photonic radiators generally require stringent and nanoscale‐precision fabrication, which greatly restricts mass production and renders them less attractive for large‐area applications. A simple, inexpensive, and scalable electrospinning method is demonstrated for fabricating a high‐performance flexible hybrid membrane radiator (FHMR) that consists of polyvinylidene fluoride/tetraethyl orthosilicate fibers with numerous nanopores inside and SiO2 microspheres randomly distributed across its surface. Even without silver back‐coating, a 300 µm thick FHMR has an average infrared emissivity >0.96 and reflects ≈97% of solar irradiance. Moreover, it exhibits great flexibility and superior strength. The daytime cooling performance this device is experimentally demonstrated with an average radiative cooling power of 61 W m−2 and a temperature decrease up to 6 °C under a peak solar intensity of 1000 W m−2. This performance is comparable to those of state‐of‐the‐art devices.
Mitigating Plasmonic Absorption Losses at Rear Electrodes in High‐Efficiency Silicon Solar Cells Using Dopant‐Free Contact Stacks
Authors: Zhong Sihua , Dreon Julie , Jeangros Quentin , Aydin Erkan , De Wolf Stefaan , Fu Fan , Boccard Mathieu , Ballif Christophe 
Published: November 2019

AbstractAlthough charge‐carrier selectivity in conventional crystalline silicon (c‐Si) solar cells is usually realized by doping Si, the presence of dopants imposes inherent performance limitations due to parasitic absorption and carrier recombination. The development of alternative carrier‐selective contacts, using non‐Si electron and hole transport layers, has the potential to overcome such drawbacks and simultaneously reduce the cost and/or simplify the fabrication process of c‐Si solar cells. Nevertheless, devices relying on such non‐Si contacts with power conversion efficiencies (PCEs) that rival their classical counterparts are yet to be demonstrated. In this study, one key element is brought forward toward this demonstration by incorporating low‐pressure chemical vapor deposited ZnO as the electron transport layer in c‐Si solar cells. Placed at the rear of the device, it is found that rather thick (75 nm) ZnO film capped with LiFx/Al simultaneously enables efficient electron selectivity and suppression of parasitic infrared absorption. Next, these electron‐selective contacts are integrated in c‐Si solar cells with MoOx‐based hole‐collecting contacts at the device front to realize full‐area dopant‐free‐contact solar cells. In the proof‐of‐concept device, a PCE as high as 21.4% is demonstrated, which is a record for this novel device class and is at the level of conventional industrial solar cells.
Functional Materials Under Stress: In Situ TEM Observations of Structural Evolution
Authors: Deng Yu , Zhang Ruopeng , Pekin Thomas C. , Gammer Christoph , Ciston Jim , Ercius Peter , Ophus Colin , Bustillo Karen , Song Chengyu , Zhao Shiteng , Guo Hua , Zhao Yunlei , Dong Hongliang , Chen Zhiqiang , Minor Andrew M. 
Published: November 2019

AbstractThe operating conditions of functional materials usually involve varying stress fields, resulting in structural changes, whether intentional or undesirable. Complex multiscale microstructures including defects, domains, and new phases, can be induced by mechanical loading in functional materials, providing fundamental insight into the deformation process of the involved materials. On the other hand, these microstructures, if induced in a controllable fashion, can be used to tune the functional properties or to enhance certain performance. In situ nanomechanical tests conducted in scanning/transmission electron microscopes (STEM/TEM) provide a critical tool for understanding the microstructural evolution in functional materials. Here, select results on a variety of functional material systems in the field are presented, with a brief introduction into some newly developed multichannel experimental capabilities to demonstrate the impact of these techniques.
The Role of the Interfaces in Perovskite Solar Cells
Authors: Shao Shuyan , Loi Maria Antonietta 
Published: November 2019

AbstractOrganic–inorganic hybrid perovskite solar cells (HPSCs) have achieved an impressive power conversion efficiency (PCE) of 25.2% in 2019. At this stage, it is of paramount importance to understand in detail the working mechanism of these devices and which physical and chemical processes govern not only their power conversion efficiency but also their long‐term stability. The interfaces between the perovskite film and the charge transport layers are among the most important factors in determining both the PCE and stability of HPSCs. Herein, an overview is provided on the recent advances in the fundamental understanding of how these interfaces influence the performance of HPSCs. Firstly, it is discussed how the surface energy of the charge transport layer, the energy level alignment at the interfaces, the charge transport in interfacial layers, defects and mobile ions in the perovskite film, and interfacial layers or at the interfaces affect the charge recombination as well as hysteresis and light soaking phenomenon. Then it is discussed how the interfaces and interfacial materials influence the stability of HPSCs. At the same time, an overview is also provided on the various design strategies for the interfaces and the interfacial materials. At the end, the outlook for the development of highly efficient and stable HPSCs is provided.
Boron‐Modified Electron Transfer in Metallic 1T MoSe2 for Enhanced Inherent Activity on Per‐Catalytic Site toward Hydrogen Evolution
Authors: Mao Zeyang , Wang Chao , Lu Haoliang , Tang Kai , Li Qun , Yan Chenglin , Wang Xianfu 
Published: November 2019

AbstractPhase‐transition‐induced electronic structure and geometry‐modulation‐increased edge sites are of great importance for boosting the electrocatalytic activity of MoSe2 toward hydrogen evolution reaction (HER). However, little efforts have been made to improve the intrinsic activity on per‐catalytic site of MoSe2 for HER. In this work, the electrocatalytic HER activities of MoSe2 are extremely enhanced by simple incorporation of boron which can reasonably engineer the electron transfer from Mo atoms to the active sites including B and Se atoms. Compared with the pristine 1T MoSe2, the as‐opimized B‐1T MoSe2 nanosheets show a reduced overpotential of 180 mV at current density of 10 mA cm−2, a lowered Tafel slope of 50.6 mV dec−1, and increased turnover frequency under a constant overpotential. While the electrochemical surface area of the catalyst after B‐incorporation is decreased, the improved inherent activity on per‐catalytic site and facilitated HER kinetics are demonstrated. The results pave the way to reasonably engineer the electron transfer to the active sites in the catalysts by B‐doping to boost the intrinsic activity on per‐catalytic site for electrocatalytic HER.
Enhancement of Open‐Circuit Voltage of Perovskite Solar Cells by Interfacial Modification with p‐Aminobenzoic Acid
Authors: Zou Yuqin , Liang Yongqi , Mu Cheng , Zhang Jian‐Ping 
Published: November 2019

AbstractVarious approaches of interface engineering are shown to be effective in improving the device performance of organic–inorganic hybrid perovskite solar cells (PSCs). The modification of the photoactive layer of PSC, CH3NH3PbI3 (MAPbI3), by spin‐coating a layer of p‐aminobenzoic acid (PABA), which can significantly enhance the open‐circuit voltage (VOC), the fill factor (FF), and the power conversion efficiency (PCE) of PSCs, is herein reported. The champion device shows a short‐circuit current (JSC) of 22.83 mA cm−2, VOC of 1.167 V, FF of 0.768, and PCE of 20.47%. The improvement in photovoltaic performance is attributed to the suppression of carrier trap states and the improvement in the morphologies of perovskite films. This work demonstrates a simple and effective protocol to enhance the device performance, and provides an insight into the influence of PABA post‐treatment on the charge carrier dynamics.
Free‐Electron Transparent Metasurfaces with Controllable Losses for Broadband Light Manipulation with Nanometer Resolution
Authors: Bonifazi Marcella , Mazzone Valerio , Li Ning , Tian Yi , Fratalocchi Andrea 
Published: November 2019

AbstractControlling broadband light in nanoscale volumes is a desired goal in nanophotonics. Metastructures tackle this problem by subwavelength nanostructured patterns. The current technology reaches footprints of 50 nm with plasmonic nanostructures. Scaling down these values is challenging, especially in low loss dielectrics. Here, a new class of metasurfaces is introduced, “printed” point‐to‐point by free‐electron waves and created by altering the resonant atomic transition of inexpensive photosensitive materials. With this approach it is possible to directly write a desired distribution of refractive index and extinction coefficient with a resolution equal to the focusing accuracy of the electron beam, theoretically limited to the single nanometer. An application of this technology is illustrated in structural coloration. Currently, the best results are obtained with plasmonics at 127 000 dual polarization interferometry (DPI), with 50–200 nm structures and chromaticity ranging from blue to yellow. Free‐electron metasurfaces can generate the complete spectrum of colors of the cyan, yellow, magenta, and black system with resolutions up to 256 000 DPI, and nanostructures of 10 nm radius by using a single inexpensive layer of transparent material. This platform can enable a new generation of low cost transparent media supporting ultradense optical circuitry for broadband light control.
Designing Multicolor Dual‐Mode Lanthanide‐Doped NaLuF4/Y2O3 Composites for Advanced Anticounterfeiting
Authors: Chen Xiao , Yao Weijing , Wang Qi , Wu Wei 
Published: November 2019

AbstractOwing to the large coding capacity and high confidentiality, dual‐mode or multimode anticounterfeiting fluorescent materials are gradually substituting traditional single‐mode fluorescent materials. Herein, a facile hydrothermal method is designed and used to integrate lanthanide ion (Ln3+)‐doped NaLuF4 nanoparticles with Y2O3‐based downconversion nanorods, achieving the construction of dual‐mode luminescent composite materials. The excellent optical properties of NaLuF4/Y2O3 composites are confirmed by photoluminescence spectroscopy. The composites can be excited by a 980 nm laser to generate bright red, green, and blue colors (corresponding to Er3+/Tm3+‐, Yb3+/Ho3+‐, and Yb3+/Tm3+‐doped NaLuF4, respectively), and turn into dim‐red and green colors under an excitation source of 254 nm. Furthermore, the polyvinyl alcohol (PVA)‐mediated stable fluorescent inks are successfully formulated and then printed onto the paper, aluminum foil, and fabric by low‐cost and simple screen printing techniques to fabricate various anticounterfeiting patterns. Interestingly, the printed patterns are hard to observe under ambient light, enabling the generation of multiple emission color under excitations of 980 and 254 nm. The prepared dual‐mode NaLuF4/Y2O3 composite materials with outstanding stability and distinctive multicolor luminescent properties provide low‐cost, highly effective, multilevel protection for genuine products against counterfeit.