bluuebunny/crossref_metadata_2025_split huggingface dataset:
Grain‐Specific Transitions Determine the Band Edge Luminescence in Dion–Jacobson Type 2D Perovskites
Authors: Kahmann Simon , Duim Herman , Rommens Alexander J. , Tekelenburg Eelco K. , Shao Shuyan , Loi Maria A. 
Published: September 2021

AbstractThe photophysics of 2D perovskites incorporating 1,4‐phenylenedimethanammonium (PDMA) as spacer cations is studied. PDMAPbI4 and PDMASnI4 exhibit absorption and luminescence spectra dominated by excitonic transitions and an emission due to two different states. Low‐temperature studies reveal a time‐dependent red shift of 12 meV that is correlated with grain‐specific luminescence spectra observed in optical micrographs. For the Pb‐variant, grains of red‐shifted and lower intensity band edge emission simultaneously exhibit a more pronounced luminescence from a broad defect‐related band around 2 eV. This suggests the grain‐specific emission to be related to local defects. These observations have important consequences for the understanding of luminescence of 2D perovskites, for which peak splitting of the band edge emission is a common, yet not completely resolved observation.
Photoionic Driven Movement of Metallic Ions as a Nonvolatile Reconfiguration Mechanism in Amorphous Chalcogenide Metasurfaces
Authors: McRae Liam , Xie Yunhui , Gholipour Behrad 
Published: September 2021

AbstractChalcogenide glasses have been widely adopted as a material platform for achieving reconfigurable metamaterials and metasurfaces, primarily through exploiting nonvolatile phase transitions inherent to these semiconductors. In such devices, the atomic lattice of the nanostructured medium reversibly changes between amorphous and crystalline phases, invoked through an energy‐intensive melt/quench process that can reduce device endurance due to chemical and geometrical drift. Metal‐doped amorphous chalcogenide semiconductors (MdACs) exhibit a directional photoinduced movement of their constituent metal‐ions when exposed to light with a photon energy equivalent or higher than the bandgap of the host chalcogenide glass. This “photoionic” movement results in nonvolatile changes of refractive index and conductivity at the nanoscale enabling a nonvolatile, nonbinary dynamic modulation of light removing the need for a phase transition. It is shown here that this photoionic movement in silver‐doped amorphous germanium selenide metasurfaces enables reversible optical switching. Understanding and integrating the photoionic mechanism within various optoelectronic device platforms presents significant potential for realizing a range of nonvolatile optically reconfigurable nanophotonic devices for emerging display, data storage, and signal processing applications.
Hybrid 2D‐QD MoS2–PbSe Quantum Dot Broadband Photodetectors with High‐Sensitivity and Room‐Temperature Operation at 2.5 µm
Authors: Kundu Biswajit , Özdemir Onur , Dalmases Mariona , Kumar Gaurav , Konstantatos Gerasimos 
Published: September 2021

AbstractBroadband infrared photodetectors have profound importance in diverse applications including security, gas sensing, bioimaging, spectroscopy for food quality, and recycling, just to name a few. Yet, these applications can currently be served by expensive epitaxially grown photodetectors, limiting their market potential and social impact. The use of colloidal quantum dots (CQDs) and 2D materials in a hybrid layout is an attractive alternative to design low‐cost complementary metal‐oxide‐semiconductor (CMOS) compatible infrared photodetectors. However, the spectral sensitivity of these conventional hybrid detectors is restricted to 2.1 µm. Herein, a hybrid structure comprising molybdenum disulfide (MoS2) with lead selenide (PbSe) CQDs is presented to extend their sensitivity further toward the mid‐wave infrared, up to 3 µm. A room‐temperature responsivity of 137.6 A W−1 and a detectivity of 7.7 × 1010 Jones are achieved at 2.55 µm owing to highly efficient photoexcited carrier separation at the interface of MoS2 and PbSe in combination with an oxide coating to reduce dark current; the highest value is yet for a PbSe‐based hybrid device. These findings strongly support the successful fabrication of hybrid devices, which may pave the pathway for cost‐effective, high‐performance, next‐generation, novel photodetectors.
Application of Mutualism in Organic Synthetic Chemistry: Mutually Promoted C−H Functionalization of Indole and Reduction of Quinoline
Authors: Zhang Sutao , Xu Hai , He Jianghua , Zhang Yuetao 
Published: September 2021

AbstractHere we reported a one‐pot, metal‐free B(C6F5)3‐catalyzed strategy for simultaneous synthesis of C3‐regioselective functionalization of indoles and complete reduction of quinolines. It turned out that by sharing a quinolinium hydridoborate intermediate, the original determining steps with high energy barrier in both the convergent disproportionation of indole and reduction of quinoline could be realized at room temperature, thus furnishing both the C3‐borylated (or silylated) indoles and N‐borylated tetrahydroquinolines in up to 98% yields at room temperature. Mechanistic studies suggested that both reactions would consume a product generated from the other reaction such that they can mutually promote each other, thus producing desirable products in a high atom‐economy and low energy‐cost manner. This strategy opened the gate to introducing mutualism to the field of chemistry.magnified image
Clean Carbon Cycle via High‐Performing and Low‐Cost Solar‐Driven Production of Freshwater
Authors: Mazzone Valerio , Bonifazi Marcella , Aegerter Christof M. , Cruz Aluizio M. , Fratalocchi Andrea 
Published: September 2021

AbstractWhile renewable power available worldwide costs increasingly less than the least expensive option based on fossil fuels, countries continue to increase their coal‐fired capacity, which should conversely fall by 80% within a decade to limit global warming effects. To address the challenges to the implementation of such an aim, here, a path is explored that leverages on a previously unrecognized aspect of coal, opening to a new solar‐driven carbon cycle that is environmentally friendly. By engineering the porosity matrix of coal into a suitably designed compressed volumetric structure, and by coupling it with a network of cotton fibers, it is possible to create a record performing device for freshwater production, with a desalination rate per raw material cost evaluated at 1.39 kg h $ at one sun intensity. This value is between two and three times higher than any other solar desalination device proposed to date. These results could envision a clean and socially sustainable cycle for carbon materials that, while enabling an enhanced water economy with global access to freshwater and sanitation, poses zero risks of reinjecting into the environment through competing economies in the fossil's market.
Enhancement Efficiency of Organic Photovoltaic Cells via Green Solvents and Nontoxic Halogen‐Free Additives
Authors: Fu Zhijie , Liu Xingpeng , Niu Xixi , Ren Meiling , Xue Luyang , Du Sanshan , Tong Junfeng , Li Jianfeng , Bao Xichang , Xia Yangjun 
Published: September 2021

AbstractFor organic photovoltaic cells, the development of new green solvents and nontoxic and halogen‐free additives is an urgent issue. Here, a simple combination of o‐xylene (O‐XY) and ethyl 2‐hydroxybenzoate (EHB) is introduced in inverted devices based on poly[4,8‐bis(5‐(2‐ethylhexyl)‐thiophene‐2‐yl) benzo[1,2‐b;4,5‐b′] dithiophene‐2,6‐diyl‐alt‐(4‐(2‐ethylhexyl)‐3‐fluorothieno[3,4‐b] thiophene)‐2‐carboxylate‐2‐6‐diyl]:[6,6]‐phenyl‐C71‐butyric acid methyl ester (PTB7‐Th:PC71BM) as blend layers, the device performance reaches optimal values (9.29%) when O‐XY and 3% EHB are introduced as additives, accompanied by the maximum fill factor (67.5%) and JSC (17.20 mA cm−2). From the results of characterization analysis, it is clear that EHB additive improves the crystallinity of the donor by regulating the kinetic process of active layer formation, selectively solubilizes the more aggregated fullerene acceptors, which allows PTB7‐Th to enter the conformational domain of PC71BM, and accelerates the molecular rearrangement. Besides, the EHB additive not only reduces the recombination, increases the carrier migration rate but also promotes the crystallinity of the donor, resulting in a tighter stacking. This work provides a green combination of solvents and additives that is important for the mass production of solar cells.
Biomimetic Wood‐Inspired Batteries: Fabrication, Electrochemical Performance, and Sustainability within a Circular Perspective
Authors: Gomez Iñaki , Lizundia Erlantz 
Published: September 2021

AbstractNature's hierarchical materials offer exceptional multifunctional properties thanks to their evolution over millions of years to reach the most optimized organization in terms of function, structure, or chemistry. Exploiting the unique features of natural materials through biomimicry offers an exciting research field with large potential for new discoveries. Wood, as one of the most fascinating biomaterials, combines unique mechanical properties, an anisotropic hierarchical porosity optimized to provide rapid, and low tortuosity pathways for nutrient/water transport, abundance, and biodegradability. Accordingly, wood has inspired scientists to mimic its outstanding properties in artificial analogues to develop batteries with remarkable electrochemical performance. For instance, its sophisticated structure can be transferred to solid‐state materials through biomimetic templating to increase the lifespan and energy density of batteries, while its inherent hierarchical multi‐channeled structure allows the synthesis of current collectors with enhanced ion and electron diffusivity. This Review highlights the recent progress into the application of wood as a hierarchically porous and renewable material to develop different battery components, including the cathode, the anode, the separator, and current collectors. The potential of wood‐inspired batteries to lessen the pressure over critical raw materials and additional environmental sustainability benefits are highlighted within a circular economy perspective.
Sulfonated Dopant‐Free Hole‐Transport Material Promotes Interfacial Charge Transfer Dynamics for Highly Stable Perovskite Solar Cells
Authors: Li Rui , Liu Maning , Matta Sri Kasi , Hiltunen Arto , Deng Zhifeng , Wang Cheng , Dai Zhicheng , Russo Salvy P. , Vivo Paola , Zhang Haichang 
Published: September 2021

AbstractThe integration of a functional group into dopant‐free hole‐transport materials (HTMs) to modify the perovskite|HTM interface has become a promising strategy for high‐performance and stable perovskite solar cells (PSCs). In this work, a sulfonated phenothiazine‐based HTM is reported, namely TAS, which consists of a butterfly structure with a readily synthesized N,​N‐​bis[4‐​(methylthio)​phenyl]​aniline side functional group. The interaction between TAS and perovskite via Pb–S bond induces a dipole moment that deepens the valence band of perovskite and thereby leads to enhanced open‐circuit voltage in corresponding n‐i‐p PSCs. More importantly, the functionalization of perovskite surface via Pb–S bond promotes the hole extraction reaction while suppressing the interfacial non‐radiative recombination, contributing to a 20–50% performance improvement compared to less‐ (4‐​(methylthio)​‐​N‐​[4‐​(methylthio)​phenyl]​aniline, DAS) or non‐interacting (N,N‐bis(4‐methoxyphenyl)aniline, TAO) counterparts. Consequently, TAS‐based PSCs exhibit superior device stability with a high PCE retention (>90% of the initial value) after 125 days of storage in the air.
Breaking Space Inversion‐Symmetry to Obtain Asymmetric Spin‐Wave Excitation in Systems with Nonuniform Magnetic Exchange
Authors: Macêdo Rair , Kudinoor Arjun S. , Livesey Karen L. , Camley Robert E. 
Published: September 2021

AbstractThe consequences of non‐uniform exchange in magnetic systems are reported. The quantum mechanical exchange interaction between spins is responsible for the phenomenon of magnetic order, and is generally considered to be uniform across bulk magnetic systems. Partly inspired by the Dzyaloshinskii‐Moriya interaction—also known as antisymmetric exchange—a linearly varying exchange interaction is used along a magnetic strip as a route to spatial inversion symmetry‐breaking. It is found that, in addition to asymmetric modes and localization, spatially varying exchange can be used to design nonreciprocal magnetic signal excitation at frequencies that are tunable. Moreover, the authors’ work predicts nonreciprocity to occur across a vast range of frequencies up to hundreds of GHz. Such spin wave engineering is a key area of ongoing research in the fields of magnonics and spintronics, which are expected to enable the next generation of wireless communication technology and information processing. Analogous nonreciprocity is expected to occur in other wave systems with gradient properties.
A Janovec‐Kay‐Dunn‐Like Behavior at Thickness Scaling in Ultra‐Thin Antiferroelectric ZrO2 Films
Authors: Tasneem Nujhat , Yousry Yasmin Mohamed , Tian Mengkun , Dopita Milan , Reyes‐Lillo Sebastian E. , Kacher Josh , Bassiri‐Gharb Nazanin , Khan Asif Islam 
Published: September 2021

AbstractOriginally based on phenomenological observations, the Janovec–Kay–Dunn (JKD) scaling law has been historically used to describe the dependence of the ferroelectric coercive fields (Ec) on a critical length scale of the material, wherein the film thickness (t) is considered the length scale, and Ec ∝ t−2/3. Here, for the first time, a JKD‐type scaling behavior is reported in an antiferroelectric material, using the ultra‐thin films of prototypical flourite‐structure binary oxide, zirconia. In these films, a decrease in the ZrO2 layer thickness from 20 nm to 5.4 nm leads to an increase in critical fields for both nonpolar‐to‐polar (Ea), and polar‐to‐nonpolar (Ef) transitions, accompanied by a decrease in the average crystallite size, and an increase in the tetragonal distortion of the non‐polar P42/nmc ground state structure. Notably, the ‐2/3 power law as in the JKD law holds when average crystallite size (d), measured from glancing‐incident X‐ray diffraction, is considered as the critical length scale—i.e., Ea, Ef ∝ d−2/3. First principles calculations suggest that the increase of tetragonality in thinner films contributes to an increase of the energy barrier for the transition from the non‐polar tetragonal ground state to the field‐induced polar orthorhombic phase, and in turn, an increase in Ea critical fields. These results suggest a de‐stabilization of the ferroelectric phase with a decreasing thickness in antiferroelectric ZrO2, which is contrary to the observations in its fluorite‐structure ferroelectric counterparts. With the recent interests in utilizing antiferroelectricity for advanced semiconductor applications, our fundamental exposition of the thickness dependence of functional responses therein can accelerate the development of miniaturized, antiferroelectric electronic memory elements for the complementary metal‐oxide‐semiconductor based high‐volume manufacturing platforms.
Ultrathin Polythiophene Films Prepared by Vertical Phase Separation for Highly Stretchable Organic Field‐Effect Transistors
Authors: Wang Xiaohong , Zhu Yingman , Liu Zhen , Yuan Ye , Qiu Longzhen 
Published: September 2021

AbstractPhysically blending semiconducting conjugated polymers with elastomeric materials and precisely controlling the resulting film structure provides an effective strategy to obtain intrinsically stretchable semiconducting polymers. Here, vertically phase‐separated ultrathin poly(3‐hexylthiophene) (P3HT) and polystyrene‐b‐polyisoprene‐b‐polystyrene (SIS) blend films are developed for one‐step fabrication of semiconductor and insulator layers of organic field effect transistors (OFETs). The phase‐separated structure, surface morphology, and tensile deformation are characterized by UV–vis absorption spectroscopy, atomic force microscopy, and optical microscopy. The blend film device maintains 43% of its mobility compared with 0.1% mobility of the pristine P3HT films after 50% stretch. The deformability of the films is efficiently improved by blending proved by both the finite element analysis and the dichroic ratio measurements. The P3HT/SIS blended films possess reproducible properties under 200 continuous stretch–release cycles at a strain of 50% without significantly reduced mobilities. The fully‐stretchable OFETs on polydimethylsiloxane substrate are also investigated and show a stretchability up to 70% and good electrical recovery properties after stretch–release process. The vertical phase‐separated structure obtained by the blends provides an effective way to easily fabricate stretchable devices with a balance between their mechanical and electrical properties.
Highly Reversible, Grain‐Directed Zinc Deposition in Aqueous Zinc Ion Batteries
Authors: Shin Jaeho , Lee Jimin , Kim Yangmoon , Park Youngbin , Kim Minkwan , Choi Jang Wook 
Published: September 2021

AbstractAchieving highly reversible Zn metal anodes is a crucial step in advancing the performance of aqueous zinc ion batteries. However, despite the relative stability of Zn metal in aqueous environments, Zn metal is plagued by deterrents such as dendritic growth, H2 evolution, and corrosion. This mainly stems from the absence of a stable solid‐electrolyte interphase (SEI), an inevitable consequence of moderate concentration aqueous electrolytes. In response to such issues, herein, an artificial SEI formed from cross‐linked gelatin is introduced by coating the surface of Zn metal. The presence of the gelatin layer significantly changes the deposition morphology of Zn, where its plated surface is much more uniform and dense compared to bare Zn metal. Interestingly, grain‐directed electrodeposition can be observed in which the crystallographic orientation of the underlying Zn metal substrate determines the directionality of electrochemically plated Zn. This mode of growth results in a highly uniform and dense surface, translating to enhanced electrochemical stability.
A High‐Rate Electrode with Grotthuss Topochemistry for Membrane‐Free Decoupled Acid Water Electrolysis
Authors: Liang Shuaika , Jiang Miaomiao , Luo Hongxia , Ma Yuanyuan , Yang Jianping 
Published: September 2021

AbstractWater electrolysis powered by renewable energies is regarded as the most promising technology for hydrogen production. However, in conventional acid water electrolysis, the H2 production and O2 production are tightly coupled and the proton exchange membrane is required to prevent the gases mixing, which reduce the flexibility of this technology and increase its cost. Here, a low‐cost hydrated Prussian blue analog (Turnbull's blue) electrode is introduced as a solid‐state redox mediator to decouple the acid water electrolysis into two steps without the use of membrane. The redox mediator shows high‐rate performance (42.7 mAh g−1 at 120 A g−1) and long cycle life (5000 cycles), which is owing to the diffusion‐free Grotthuss proton conduction. Moreover, this decoupled water electrolysis device facilitates the utilization of renewable energies for high‐purity hydrogen production at different spaces and times, which shows the high flexibility for H2 production.
ED EMS time: A COVID‐friendly alternative to ambulance ride‐alongs
Authors: Grawey Tom , Hinze Janice , Weston Benjamin 
Published: September 2021

AbstractBackgroundAmbulance ride‐alongs are frequently a critical element of educational programs for learners of prehospital emergency care. We describe a novel alternative to the EMS ride‐along experience more conducive to COVID‐19 restrictions.Methods“ED EMS time” was developed as an alternative training method to provide a field‐type experience within the emergency department (ED) setting. Over the course of a 4‐h shift, medical students observe and complete standardized reflections on online medical control radio consultations and EMS‐to‐ED patient handoffs. Medical students also interview EMS clinicians to gain insight into prehospital care and the challenges that occur in the field. Experiences are debriefed with an EMS attending.ResultsMedical students expressed increased knowledge around the challenges and treatment capabilities of EMS through the ED EMS time experience. They were able to explain what information obtained from the scene was helpful to EMS clinicians. Medical students were able to realize the objectives of ambulance ride time through an ED experience designed around EMS.ConclusionsED EMS time represents a novel approach to teaching medical students the intricacies of prehospital medicine from the confines of the ED while avoiding direct patient contact, preserving PPE, and limiting COVID‐19 exposure.
Moving beyond personal factors: A national study of wellness interventions in emergency medicine residency programs
Authors: Li‐Sauerwine Simiao , Rebillot Katie , Chung Arlene S. , Coates Wendy C. , Shah Sneha , Yarris Lalena M. 
Published: September 2021

AbstractBackgroundIn 2017, the Accreditation Council for Graduate Medical Education (ACGME) revised its Common Program Requirements to support trainees and faculty by mandating programs to provide dedicated wellness resources and education. Emergency medicine may benefit from this change due to high burnout rates within the specialty. However, the current state of wellness interventions in emergency medicine (EM) residency programs has not yet been well described. Understanding current practices is necessary to assess unmet needs and inform the development and evaluation of future interventions that aim to improve trainee wellness.ObjectivesThe goal of this study was to describe currently implemented wellness interventions in EM residency programs.MethodsThis descriptive study surveyed 250 ACGME‐accredited EM residency programs between March 1 and June 1, 2020, regarding wellness interventions. The survey included demographic questions; structured multiple‐choice questions about cost, frequency, and champions; and free‐text response options to briefly describe interventions. Respondents were also asked to classify the interventions according to the seven factors described in the National Academy of Medicine Model of Clinician Well‐Being and Resilience.ResultsNinety of 250 (36% response rate) residency programs participated, describing 162 unique wellness interventions. Respondents classified the majority of interventions (n = 136) as targeting personal factors according to the National Academy of Medicine model. Qualitative analysis revealed five major themes describing the interventions: program culture, program factors, environmental and clinical factors, wellness activities and practices, and wellness resources.ConclusionsResults of this survey may help to inform a national needs assessment addressing the current state of wellness interventions in EM residency programs. Our results highlight the need for more interventions targeting external factors impacting resident wellness.