bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quantifying Efficiency Loss of Perovskite Solar Cells by a Modified Detailed Balance Model
Authors: Sha Wei E. I. , Zhang Hong , Wang Zi Shuai , Zhu Hugh L. , Ren Xingang , Lin Francis , Jen Alex K.‐Y. , Choy Wallace C. H. 
Published: December 2017

AbstractA modified detailed balance model is built to understand and quantify efficiency loss of perovskite solar cells. The modified model captures the light‐absorption‐dependent short‐circuit current, contact and transport‐layer‐modified carrier transport, as well as recombination and photon‐recycling‐influenced open‐circuit voltage. The theoretical and experimental results show that for experimentally optimized perovskite solar cells with the power conversion efficiency of 19%, optical loss of 25%, nonradiative recombination loss of 35%, and ohmic loss of 35% are the three dominant loss factors for approaching the 31% efficiency limit of perovskite solar cells. It is also found that the optical loss climbs up to 40% for a thin‐active‐layer design. Moreover, a misconfigured transport layer introduces above 15% of energy loss. Finally, the perovskite‐interface‐induced surface recombination, ohmic loss, and current leakage should be further reduced to upgrade device efficiency and eliminate hysteresis effect. This work contributes to fundamental understanding of device physics of perovskite solar cells. The developed model offers a systematic design and analysis tool to photovoltaic science and technology.
High Thermoelectric zT in n‐Type Silver Selenide films at Room Temperature
Authors: Perez‐Taborda Jaime Andres , Caballero‐Calero Olga , Vera‐Londono Liliana , Briones Fernando , Martin‐Gonzalez Marisol 
Published: December 2017

AbstractIn this work, a zT value as high as 1.2 at room temperature for n‐type Ag2Se films is reported grown by pulsed hybrid reactive magnetron sputtering (PHRMS). PHRMS is a novel technique developed in the lab that allows to grow film of selenides with different compositions in a few minutes with great quality. The improved zT value reported for room temperature results from the combination of the high power factors, similar to the best values reported for bulk Ag2Se (2440 ± 192 µW m−1 K−2), along with a reduced thermoelectric conductivity as low as 0.64 ± 0.1 W m−1 K−1. The maximum power factor for these films is of 4655 ± 407 µW m−1 K−2 at 103 °C. This material shows promise to work for room temperature applications. Obtaining high zT or, in other words, high power factor and low thermal conductivity values close to room temperature for thin films is of high importance to develop a new generation of wearable devices based on thermoelectric heat recovery.
3D TiC/C Core/Shell Nanowire Skeleton for Dendrite‐Free and Long‐Life Lithium Metal Anode
Authors: Liu Sufu , Xia Xinhui , Zhong Yu , Deng Shengjue , Yao Zhujun , Zhang Liyuan , Cheng Xin‐Bing , Wang Xiuli , Zhang Qiang , Tu Jiangping 
Published: December 2017

AbstractConstruction of stable dendrite‐free Li metal anode is crucial for the development of advanced Li–S and Li–air batteries. Herein, self‐supported TiC/C core/shell nanowire arrays as skeletons and confined hosts of molten Li forming integrated trilayer TiC/C/Li anode are described. The TiC/C core/shell nanowires with diameters of 400–500 nm exhibit merits of good lithiophilicity, high electrical conductivity, and abundant porosity. The as‐prepared TiC/C/Li anode exhibits prominent electrochemical performance with a small hysteresis of less than 85 mV beyond 200 cycles (3.0 mA cm−2) as well as a very high Coulombic efficiency up to 98.5% for 100 cycles at 1.0 mA cm−2. When the structured anode is coupled with lithium iron phosphate or sulfur cathode, the assembled full cells with trilayer TiC/C/Li anodes display enhanced capability retention and improved Coulombic efficiency. This is ascribed to the unique TiC/C matrix, which can not only provide interspace for accommodating “hostless” Li, but also afford interconnected rapid transfer paths for electrons and ions with low local current densities, leading to effective inhabitation growth of Li dendrites and lower interfacial resistance. A fresh way for construction of advanced stable Li metal anodes is provided in this work.
Reverse Bias Behavior of Halide Perovskite Solar Cells
Authors: Bowring Andrea R. , Bertoluzzi Luca , O'Regan Brian C. , McGehee Michael D. 
Published: December 2017

AbstractThe future commercialization of halide perovskite solar cells relies on improving their stability. There are several studies focused on understanding degradation under operating conditions in light, but little is known about the stability of these solar cells under reverse bias conditions. Reverse bias stability is important because shaded cells in a module are put into reverse bias by the illuminated cells. In this paper, a phenomenological study is presented of the reverse bias behavior of halide perovskite solar cells and it is shown that reverse bias can lead to a partially recoverable loss in efficiency, primarily caused by a decrease in V
OC. A general mechanism is proposed, supported by drift–diffusion simulations, to explain how these cells breakdown via tunneling caused by accumulated ionic defects and suggests that the reversible loss in efficiency may be due to an electrochemical reaction of these defects. Finally, the implications of these phenomena are discussed and how they can possibly be addressed is also discussed.
A Wireless Triboelectric Nanogenerator
Authors: Mallineni Sai Sunil Kumar , Dong Yongchang , Behlow Herbert , Rao Apparao M. , Podila Ramakrishna 
Published: December 2017

AbstractA new “wireless” paradigm for harvesting mechanical energy via a 3D‐printed wireless triboelectric nanogenerator (W‐TENG) comprised of an ecofriendly graphene polylactic acid (gPLA) nanocomposite and Teflon is demonstrated. The W‐TENG generates very high output voltages >2 kV with a strong electric field that enables the wireless transmission of harvested energy over a distance of 3 m. The W‐TENG exhibited an instantaneous peak power up to 70 mW that could be wirelessly transmitted for storage into a capacitor obviating the need for hard‐wiring or additional circuitry. Furthermore, the use of W‐TENG for wireless and secure actuation of smart‐home applications such as smart tint windows, temperature sensors, liquid crystal displays, and security alarms either with a single or a specific user‐defined passcode of mechanical pulses (e.g., Fibonacci sequence) is demonstrated. The scalable additive manufacturing approach for gPLA‐based W‐TENGs, along with their high electrical output and unprecedented wireless applications, is poised for revolutionizing the present mechanical energy harvesting technologies.
Multi–source surveillance for work‐related crushing injuries
Authors: Kica Joanna , Rosenman Kenneth D. 
Published: December 2017

BackgroundWork‐related crushing injuries are serious but preventable. For 2013 through 2015, the U.S. Bureau of Labor Statistics’ (BLS) Survey of Occupational Injuries and Illnesses (SOII) reported 1260 crushing injuries in Michigan. In 2013, Michigan initiated multi‐data source surveillance of work‐related crushing injuries.MethodsRecords from all 134 of Michigan's hospitals/emergency departments (EDs), the Workers Compensation Agency (WCA) and Michigan's Fatality Assessment Control and Evaluation (MIFACE) program were used to identify work‐related crushing injuries. Companies, where individuals were hospitalized or had an ED visit for a crushing injury, potentially had an OSHA enforcement inspection conducted.ResultsFrom 2013 through 2015, there were 3137 work‐related crushing injury incidents, including two fatalities. The Michigan OSHA program completed inspections at 77 worksites identified by the surveillance system.ConclusionThe Michigan multisource surveillance system identified two and a half times more crushing injuries than BLS and was useful for initiating case‐based enforcement inspections.
Komplementäre Strategien für die dirigierte C(sp3)‐H‐Funktionalisierung: ein Vergleich von übergangsmetallkatalysierter Aktivierung, Wasserstoffatomtransfer und Carben‐ oder Nitrentransfer
Authors: Chu John C. K. , Rovis Tomislav 
Published: December 2017

AbstractFunktionalisierungen von C(sp3)‐H‐Bindungen verkürzen und vereinfachen chemische Synthesen, indem sie die Verwendung einfacher Moleküle ermöglichen und neuartige Retrosynthesen bereitstellen. Intensive Forschungen, die auf die Entwicklung neuer Reaktionen basierend auf dem Ansatz der C‐H‐Funktionalisierung abzielten, haben zur weiten Verbreitung dieser Methoden in einer Vielzahl von Bereichen geführt. Dieser Aufsatz erörtert die Stärken und Schwächen der drei Hauptstrategien – übergangsmetallkatalysierte C‐H‐Aktivierung, 1,n‐Wasserstoffatomtransfer und übergangsmetallkatalysierter Carben‐ oder Nitrentransfer – in der gezielten Funktionalisierung nichtaktivierter C(sp3)‐H‐Bindungen. Für jede Strategie werden der Anwendungsbereich, die Reaktivität verschiedener C‐H‐Bindungen, die Position der reagierenden C‐H‐Bindungen bezüglich der dirigierenden Gruppe und die stereochemischen Auswirkungen mit Beispielen aus der Literatur veranschaulicht. Das Ziel dieses Aufsatzes ist es, dem Anwender von C‐H‐Funktionalisierungsreaktionen eine Orientierungshilfe zu geben und künftige Forschungen auf diesem Gebiet anzuregen.
A Molecular Approach to Manganese Nitride Acting as a High Performance Electrocatalyst in the Oxygen Evolution Reaction
Authors: Walter Carsten , Menezes Prashanth W. , Orthmann Steven , Schuch Jona , Connor Paula , Kaiser Bernhard , Lerch Martin , Driess Matthias 
Published: December 2017

AbstractThe scalable synthesis of phase‐pure crystalline manganese nitride (Mn3N2) from a molecular precursor is reported. It acts as a superiorly active and durable electrocatalyst in the oxygen evolution reaction (OER) from water under alkaline conditions. While electrophoretically deposited Mn3N2 on fluorine tin oxide (FTO) requires an overpotential of 390 mV, the latter is substantially decreased to merely 270 mV on nickel foam (NF) at a current density of 10 mA cm−2 with a durability of weeks. The high performance of this material is due to the rapid transformation of manganese sites at the surface of Mn3N2 into an amorphous active MnOx overlayer under operation conditions intimately connected with metallic Mn3N2, which increases the charge transfer from the active catalyst surface to the electrode substrates and thus outperforms the electrocatalytic activity in comparison to solely MnOx‐based OER catalysts.
Generating Hydrated Electrons for Chemical Syntheses by Using a Green Light‐Emitting Diode (LED)
Authors: Naumann Robert , Lehmann Florian , Goez Martin 
Published: December 2017

AbstractWe present the first working system for accessing and utilizing laboratory‐scale concentrations of hydrated electrons by photoredox catalysis with a green light‐emitting diode (LED). Decisive are micellar compartmentalization and photon pooling in an intermediate that decays with second‐order kinetics. The only consumable is the nontoxic and bioavailable vitamin C. A turnover number of 1380 shows the LED method to be on par with electron generation by high‐power pulsed lasers, but at a fraction of the cost. The extreme reducing power of the electron and its long unquenched life as a ground‐state species are synergistic. We demonstrate the applicability to the dechlorination, defluorination, and hydrogenation of compounds that are inert towards all other visible‐light photoredox catalysts known to date. A comprehensive mechanistic investigation from microseconds to hours yields results of general validity for photoredox catalysis with photon pooling, allowing optimization and upscaling.
Slow Magnetic Relaxation and Single‐Molecule Toroidal Behaviour in a Family of Heptanuclear {CrIIILnIII6} (Ln=Tb, Ho, Er) Complexes
Authors: Vignesh Kuduva R. , Langley Stuart K. , Swain Abinash , Moubaraki Boujemaa , Damjanović Marko , Wernsdorfer Wolfgang , Rajaraman Gopalan , Murray Keith S. 
Published: December 2017

AbstractThe synthesis, magnetic properties, and theoretical studies of three heterometallic {CrIIILnIII6} (Ln=Tb, Ho, Er) complexes, each containing a metal topology consisting of two Ln3 triangles connected via a CrIII linker, are reported. The {CrTb6} and {CrEr6} analogues display slow relaxation of magnetization in a 3000 Oe static magnetic field. Single‐crystal measurements reveal opening up of the hysteresis loop for {CrTb6} and {CrHo6} molecules at low temperatures. Ab initio calculations predict toroidal magnetic moments in the two Ln3 triangles, which are found to couple, stabilizing a con‐rotating ferrotoroidal ground state in Tb and Ho examples and extend the possibility of observing toroidal behaviour in non DyIII complexes for the first time.
Kooperative Bildung einer langreichweitig geordneten Wasserschicht auf der Fe3O4(111)‐Oberfläche
Authors: Mirabella Francesca , Zaki Eman , Ivars‐Barceló Francisco , Li Xiaoke , Paier Joachim , Sauer Joachim , Shaikhutdinov Shamil , Freund Hans‐Joachim 
Published: December 2017

AbstractDie ersten Elementarschritte in der Adsorption von Wasser auf der Magnetit(111)‐Oberfläche und die atomare Struktur der Wasser/Metalloxid‐Grenzfläche werden kontrovers diskutiert. Hier werden experimentelle Befunde präsentiert, die durch Infrarot‐Reflexions‐Absorptions‐Spektroskopie und temperaturprogrammierte Desorption erhalten wurden. Unterstützende DFT‐Rechnungen zeigen, dass Wassermoleküle an Fetet‐ und O‐Atomen dissoziativ unter Bildung zweier Hydroxo‐Spezies adsorbieren. Diese wirken als Anker für weitere Wassermoleküle, wobei Dimere entstehen. Diese ordnen sich zu einer definierten (2×2)‐Überstruktur an. Die Entstehung dieser geordneten Wasserschicht erfolgt durch eine kooperative Wechselwirkung zwischen den Dimeren und wird durch den Aufbau eines 2D‐Netzwerks über H‐Brücken angetrieben.
Complementary Strategies for Directed C(sp3)−H Functionalization: A Comparison of Transition‐Metal‐Catalyzed Activation, Hydrogen Atom Transfer, and Carbene/Nitrene Transfer
Authors: Chu John C. K. , Rovis Tomislav 
Published: December 2017

AbstractThe functionalization of C(sp3)−H bonds streamlines chemical synthesis by allowing the use of simple molecules and providing novel synthetic disconnections. Intensive recent efforts in the development of new reactions based on C−H functionalization have led to its wider adoption across a range of research areas. This Review discusses the strengths and weaknesses of three main approaches: transition‐metal‐catalyzed C−H activation, 1,n‐hydrogen atom transfer, and transition‐metal‐catalyzed carbene/nitrene transfer, for the directed functionalization of unactivated C(sp3)−H bonds. For each strategy, the scope, the reactivity of different C−H bonds, the position of the reacting C−H bonds relative to the directing group, and stereochemical outcomes are illustrated with examples in the literature. The aim of this Review is to provide guidance for the use of C−H functionalization reactions and inspire future research in this area.
Synthesis and properties of polylactide terpolymers P(LLA‐TMC‐GA) catalyzed by zirconium (IV) acetylacetonate
Authors: Wen Shaohua , Li Yongfei , Chen Weixing , Lei Yaping , Luo Chunyan , Hou Yonggang 
Published: December 2017

A series of L‐lactide (LLA), 1,3‐trimethylene carbonate (TMC) and glycolide (GA) terpolymers (LTG) of different monomer molar ratios were synthesized by using ring‐opening copolymerization. An effective and low‐toxic zirconium (IV) acetylacetonate Zr(Acac)4was used as catalyst. The viscosity‐average molecular weights (Mη) of obtained polymers were all above 2.2×104 g/mol. The chemical structure and viscosity of terpolymers were confirmed by Fourier transform infrared spectroscopy (FTIR),1H nuclear magnetic resonance (1HNMR),13C nuclear magnetic resonance (13CNMR) and an Ubbelohde viscometer. The thermal and mechanical properties were investigated by means of differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X‐ray diffraction (XRD) and stress‐strain measurements. Results suggested that all terpolymers were amorphous and showed good thermal stability. Also it was found that elongation increased with the decreasing of LLA unit. More importantly, terpolymers displayed shape memory property when deformation temperatures were 14‐15 °C aboveTg.
Formation of PdNiZn thin film at oil‐water interface: XPS study and application as Suzuki‐Miyaura catalyst
Authors: Fatahi Parvin , Jafar Hoseini S. 
Published: December 2017

Nanosheet of PdNiZn and nanosphere of PdNiZn/reduced‐graphene oxide (RGO) with sub‐3 nm spheres have been successfully synthesized through a facile oil‐water interfacial strategy. The morphology and composition of the films were determined by X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive analysis of X‐ray (EDAX) and elemental mapping. In the present study, we have developed a method to minimize the usage of precious Pd element. Due to the special structure and intermetallic synergies, the PdNiZn and PdNiZn/RGO nanoalloys exhibited enhanced catalytic activity and durability relative to Pd nanoparticles in Suzuki‐Miyaura C‐C cross‐coupling reaction. Compared to classical cross‐coupling reactions, this method has the advantages of a green solvent, short reaction times, low catalyst loading, high yields and reusability of the catalysts.
Kinetics of continuous production of β‐carotene in an airlift bioreactor
Authors: Taavoni Shoeib , Habibi Alireza , Varmira Kambiz , Alipour Sajad 
Published: December 2017

AbstractThe focus in the present work was on the continuous β‐carotene production from free fatty acids supplied by the soap stock as a sole carbon source for Rhodotorula rubra cells in an airlift bioreactor. The effects of dilution rate on the cell growth and β‐carotene production were studied by both freely suspended‐ and immobilized‐cell systems in the chemostat operations. The results showed that the immobilization of the cell on natural sponge of loofah significantly increased the optimum and maximum dilution rates from 0.0375 to 0.05 hr−1 and 0.055 to 0.150 hr−1, respectively. The immobilization process has practical role in balancing of cell proliferation in the matrix and wash out the grown cells containing β‐carotene from the bioreactor where β‐carotene productivity was enhanced from 5.4 to 23.4 mg L−1 hr−1 using the immobilized cell technology.
Enhancement of the mechanical properties and thermostability of poly(vinyl alcohol) nanofibers by the incorporation of sodium chloride
Authors: Shi Yan , Zhao Yuming , Li Xinhua , Yan Dongpeng , Cao Ding , Fu Zhifeng 
Published: December 2017

ABSTRACTThe mechanical properties and thermostability of poly(vinyl alcohol) (PVA) nanofiber mats have been obviously improved by the incorporation of sodium chloride (NaCl). The tensile properties including tensile strength and modulus of membranes with an addition of 1.0 wt % NaCl increased from 2.51 to 4.22 MPa and 33.0 to 176.30 MPa, respectively, more than 160 and 700% of those of the electrospun pure PVA membranes. Moreover, thermogravimetric analysis showed that the initial decomposition temperature (Ti) and the half decomposing temperature (T50%) of PVA nanofibers with the addition of NaCl were at least 26 and 59 °C higher than that of pure PVA nanofibers, respectively, indicating a strong interaction between the PVA and the salt ions. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45981.
Comparative mucoadhesive study of hyaluronic acid‐based conjugates on different mucosae
Authors: Laffleur Flavia 
Published: December 2017

ABSTRACTThe incentive of this study was to provide a detailed mucoadhesive comparison on adhesive properties on diverse mucosal surfaces such as nasal, buccal, and vaginal mucosa, respectively. Mucoadhesive hyaluronic acid–cysteine ethyl ester (HA–SH) conjugate was synthesized by the anchorage of sulfhydryl groups (SH) on the polymeric backbone of HA via amide bond formation between the carboxylic acid moieties of hyaluronic acid and sulfhydryl groups of cysteine ethyl ester. Histology assay in terms of alcian blue staining was performed on mucosal tissue in order to evaluate the potential impact on viability. The proficiency of water uptake was studied in various simulated body fluid. Moreover, mucoadhesive assays based on rotating cylinder, total work of adhesion, and maximum detachment force were carried out on various mucosae. The findings revealed in presence of 2.7‐, 2.6‐, and 1.25‐fold improvement in swelling behavior in comparison to unmodified HA on nasal, buccal, and vaginal mucosa. Furthermore, mucoadhesive studies showed a 3.2‐, 2.6‐, 2.6‐fold more extended residence time on nasal, buccal, and vaginal in presence of HA–SH in comparison to unmodified HA, respectively. Taken together, the comprehensive mucoadhesive study serve as guidance in the development of mucoadhesive drug delivery systems for versatile application. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46071.
Layer‐by‐layer fabrication of nacre inspired epoxy/MMT multilayered composites
Authors: Batool Sadia , Gill Rohama , Arshad Muhammad , Siddiqi Humaira Masood , Qureshi Shahid Saeed 
Published: December 2017

ABSTRACTThe organic–inorganic hybrid multilayered composites are prepared using a unique combination of poly[(o‐cresyl glycidyl ether)‐co‐formaldehyde] (CNER), amino modified montmorillonite (NH2‐MMT), and polyethyleneimine (PEI). This tricomponent composite multilayer PEI(CNER/NH2‐MMT/PEI)n deposited via layer‐by‐layer technique is based upon synergistic combination of covalent and hydrogen bonding. The growth of multilayer was monitored using UV–vis spectroscopy and ellipsometry. When subjected to optical analyses, the prepared multilayered composite films revealed profound optical transmittance ∼83%–87%. The surface morphological analysis by atomic force microscopy and scanning electron microscopy revealed uniform arrangement of organic–inorganic components with relative increase in intensity of elements (C, N, O, Si) as confirmed by X‐ray photoelectron spectroscopy studies. The multilayered composites possess 1.99 GPa hardness making them potential candidate for a number of applications where mechanical strength is desired. Moreover, significant resistance against alkaline and organic solvents at minimal deterioration of circa 0.12% has also been observed for the prepared films. The epoxy clay based thin films being robust, scratch resistant, hydrophilic, chemically inert, and mechanically strong are potential candidates for advanced environmental applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46079.
United States–China Trade: President Trump's Misunderstandings
Authors: Huenemann Ralph W. 
Published: December 2017

AbstractPresident Trump's analysis of the persistent United States–China trade imbalance reveals fundamental misunderstandings of basic economics. During the 2016 campaign, candidate Trump made an important Big Promise with two facets: to bring back American jobs from other countries (especially China) and to eliminate the American trade deficit. But, as pointed out by Barack Obama in his farewell address, many of the American jobs were lost to factory automation, not to imports. Furthermore, if China's central bank had pursued a less interventionist foreign exchange rate policy, most of the labor‐intensive imports from China would have been produced in other low‐wage countries, not in domestic factories. Finally, and most importantly, the persistent American foreign trade deficits (with many countries, not just with China) arise from the domestic imbalance between taxes and government expenditures. Unless this budget imbalance is dealt with, the foreign trade imbalance will necessarily continue.