bluuebunny/crossref_metadata_2025_split huggingface dataset:
Surface Potential Visualization in Organic Antiambipolar Transistors Using Operando Kelvin Probe Force Microscopy for Understanding the Comprehensive Carrier Transport Mechanism
Authors: Hayakawa Ryoma , Takeiri Soichiro , Yamada Yoichi , Wakayama Yutaka 
Published: December 2022

AbstractAn antiambipolar transistor (AAT) exhibits a negative differential transconductance (NDT) due to a partially overlapped p–n junction formed in the transistor channel. However, the NDT origin remains unclear. In this study, the operando Kelvin probe force microscopy is employed to unveil this issue. When the AAT is turned on, steep potential drops induced by pinch‐off states are visible in the p‐ and n‐type channels. Due to the similarity to the surface potential profiles in the constituent transistors, it is revealed that the pinch‐off points are formed at both edges of the p–n‐stacked layers. This result indicates that the overlapped layers behave like a pseudo‐drain electrode for both transistor channels. Therefore, the AAT drain current can be explained as the overlapped currents in the saturation regions of the p‐ and n‐type transistors. Moreover, the drain current is suppressed when either the p‐ or n‐type channel is completely depleted. The depletion layer formation is responsible for the NDT property. This technique provides a comprehensive understanding of the carrier transport mechanism of AATs, leading to the further evolution of organic electronic circuits.
Conversion of ALD CuO Thin Films into Transparent Conductive p‐Type CuI Thin Films
Authors: Weiß Alexander , Goldmann Jacqueline , Kettunen Sakari , Popov Georgi , Iivonen Tomi , Mattinen Miika , Jalkanen Pasi , Hatanpää Timo , Leskelä Markku , Ritala Mikko , Kemell Marianna 
Published: December 2022

AbstractCopper iodide (CuI) is a high‐performance p‐type transparent semiconductor that can be used in numerous applications, such as transistors, diodes, and solar cells. However, the lack of conformal and scalable methods to deposit CuI thin films limits its establishment in applications that involve complex‐shaped and/or large substrate areas. In this work, atomic layer deposition (ALD) is employed to enable scalable and conformal thin film deposition. A two‐step approach relying on ALD of CuO and its subsequent conversion to CuI via exposure to HI vapor at room temperature is demonstrated. The resulting CuI films are phase‐pure, uniform, and of high purity. Furthermore, CuI films on several substrates such as Si, amorphous Al2O3, n‐type TiO2, and γ‐CsPbI3perovskite are prepared. With the resulting n‐TiO2/p‐CuI structure, the easy and straightforward fabrication of a diode structure as a proof‐of‐concept device is demonstrated. Moreover, the successful deposition of CuI on γ‐CsPbI3proves the compatibility of the process for using CuI as the hole transport layer in perovskite solar cell applications in the nip‐configuration. It is believed that the ALD‐based approach described in this work will offer a viable alternative for depositing transparent conductive p‐type CuI thin films in applications that involve complex high aspect ratio structures and large substrate areas.
An Effective Charge Neutralization Enabled by Graphene Overlayer in Ambient Pressure XPS Measurements of Insulators
Authors: Yang Chueh‐Cheng , Tsai Meng‐Hsuan , Yang Zong‐Ren , Yang Yaw‐Wen , Tseng Yuan‐Chieh , Wang Chia‐Hsin 
Published: December 2022

AbstractAmbient pressure XPS is a powerful technique capable of performing measurements with samples kept at mbar pressure. The filled gas, also X‐ray ionized, provides electrons to neutralize positive charges built up on insulating samples. However, this convenient neutralization scheme does not solve the charging problem completely. In this study, the effectiveness of how the electrons generated from conducting mechanical parts mounted in the immediate front of insulating samples neutralize positive charges on the samples during XPS measurements is tested. The mechanical parts range from fine gold mesh, holey carbon film to graphene monolayer, and measured insulating samples are polished sapphire and rough pellets of CaCO3 powder. All these mechanical add‐ons reduce the charging to different degrees at the expense of sample signal. Amazingly, the graphene monolayer is found to effect perfect charge neutralization for both smooth sapphire and rough CaCO3 pellet, evidenced by realistic spectral profile and binding energy values. The finding that an untreated CaCO3 pellet is often terminated with Ca(OH)(HCO3) is consistent with earlier reports. It is speculated that a likely conformal covering with graphene on the sample with rough morphology holds the key to its superb performance in charge compensation.
Van der Waals Epitaxy of HgCdTe Thin Films for Flexible Infrared Optoelectronics
Authors: Pan Wenwu , Zhang Zekai , Gu Renjie , Ma Shuo , Faraone Lorenzo , Lei Wen 
Published: December 2022

AbstractVan der Waals epitaxial (vdW) growth of semiconductor thin films on 2D layered substrates has recently attracted considerable attention since it provides a potential pathway for realizing monolithically integrated devices and flexible devices. In this work, direct growth of epitaxial HgCdTe (111) thin films on 2D layered transparent mica substrates is achieved via molecular beam epitaxy. The full width at half maximum of the ω‐mode X‐ray diffraction peak is measured to be around 306 arc sec. Mid‐wave infrared photoconductors based on the as‐grown HgCdTe thin films have been demonstrated and the self‐heating effect has been evaluated. A peak responsivity at the wavelength of around 3500 nm is measured to be about 110 V W−1 at 80 K and 8 V W−1 at room temperature under a bias of 25 V cm−1. Twinning defects are observed, limiting the crystallinity and mobility‐lifetime product in HgCdTe/mica. Benefiting from the vdW epitaxial growth, an etch‐free layer transfer process for lifting off the HgCdTe from the mica substrate has been demonstrated, leading to large area free‐standing HgCdTe thin films.
High‐Temperature Degradation Mechanism of Interfacial Thermal Resistance Based on Submicron Silver Adhesion
Authors: Wang Jian , Fu Zhiwei , Zhao Huanhuan , Li Zhiqiang , Ma Dezhi , Yang Chao , He Zhiyuan , Guo Xiaotong , Yang Xiaofeng , Chen Si , Liu Linhua , Yang Jia‐Yue 
Published: December 2022

AbstractThermal interface materials (TIM) represented by submicron silver adhesive provide a promising solution for ultra‐high heat dissipation in chip integration. However, it is difficult to accurately characterize the thermal performance of submicron silver adhesive interfaces, and their high‐temperature degradation mechanism still remains unclear. Herein, the accelerated high‐temperature aging experiments of submicron silver adhesion interfaces are performed, and a non‐destructive testing method is provided to measure the degeneration of interfacial thermal resistance (ITR). After performing the two‐sided test, ITR can be extracted with an error of less than 4.6%. Based on scanning electron microscopy and X‐ray microstructural analysis, the microstructural evolution of silver adhesive interfaces is presented and its high‐temperature degradation mechanism is determined. It is observed for the first time that ITR would change with the aging time following a bathtub curve. Such a degenerative process can be evidently divided into three stages including secondary solidification, fluctuation, and failure. In addition, a physical model is developed to interpret the degradation mechanism of ITR at high temperatures. The change in the trend of submicron silver body and TIM–solid contact thermal resistance at different stages is presented. This work helps promote submicron silver's application as high‐performance TIM.
Amine‐Rich Hydrogels Enhance Solar Water Oxidation via Boosting Proton‐Coupled Electron Transfer
Authors: Bae Sanghyun , De Guzman Rod Alexei Fitrian , Jeon Dasom , Kim Minjung , Ryu Jungki 
Published: December 2022

AbstractPhotoelectrochemical (PEC) water oxidation is a highly challenging task that acts as a bottleneck for efficient solar hydrogen production. It is because each cycle of water oxidation is composed of four proton‐coupled electron transfer (PCET) processes and conventional photoanodes and cocatalysts have limited roles in enhancing the charge separation and storage rather than in enhancing catalytic activity. In this study, a simple and generally applicable strategy to improve the PEC performance of water oxidation photoanodes through their modification with polyethyleneimine (PEI) hydrogel is reported. The rich amine groups of PEI not only allow the facile and stable modification of photoanodes by crosslinking but also contribute to improving the kinetics of PEC water oxidation by boosting the PCET. Consequently, the PEC performance of various photoanodes, such as BiVO4, Fe2O3, and TiO2, is significantly enhanced in terms of photocurrent densities and onset potentials even in the presence of notable cocatalyst, cobalt phosphate. The present study provides new insights into and strategies for the design of efficient photoelectrodes and PEC devices.
Sequential Use of Orthogonal Self‐Assembled Monolayers for Area‐Selective Atomic Layer Deposition of Dielectric on Metal
Authors: Liu Tzu‐Ling , Harake Maggy , Bent Stacey F. 
Published: December 2022

AbstractAlthough there have been several demonstrations of area‐selective atomic layer deposition (AS‐ALD) of dielectric on dielectric in metal/dielectric patterns, the reverse process of selective dielectric on metal (DoM) is not as well developed due to the challenge of inhibiting only the dielectrics. Unavoidable native oxide formation on metals tends to lead to similar surface chemical properties between metal and dielectric substrates, decreasing the selectivity in inhibitor adsorption. Hence, to achieve DoM, preventing unwanted inhibitor adsorption on metals is critical. This study demonstrates a two‐step strategy of first applying a dodecanethiol (DDT) self‐assembled monolayer (SAM) on a Cu/SiO2 pattern to protect the Cu surfaces from subsequent deposition of an octadecyltrimethoxysilane (OTMS) inhibitor, which then selectively forms an OTMS SAM on SiO2. It is further shown that by removing the DDT protector with thermal treatment before AS‐ALD, subsequent ALD growth on Cu is not affected while ALD remains blocked on the OTMS‐covered SiO2 regions. Using this strategy, DoM is demonstrated with selectivity above 0.9 after 5.6 nm of ZnO and 1.5 nm of Al2O3 ALD. This work presents a new approach to expand the material systems available to AS‐ALD which may help enable more applications in microelectronics, optoelectronics, and energy.
Bromide Decorated Eco‐Friendly ZnSeTe/ZnSe/ZnS Quantum Dots for Efficient Blue Light‐Emitting Diodes
Authors: Zheng Zhishuai , Ren Zhenwei , Xia Wenlin , Luo Chengzhao , Li Jie , Ma Wenchen , Ji Huifeng , Shi Hengfei , Chen Yu 
Published: December 2022

AbstractMulti‐shelled ZnSeTe/ZnSe/ZnS quantum dots (QDs) have served as a promising eco‐friendly emitter for blue quantum dot light‐emitting diodes (QLEDs). While extensive studies have concentrated on the optimization of the shell species and thickness of the multi‐shelled QDs to raise the QLED electroluminescent performance, very few reports focus on the QD surface states involving ligand and defect modulations which are essential for high‐performance QLEDs. Herein, the strategy of bromide decoration is theoretically and practically demonstrated to simultaneously diminish the QD surface defects by passivating the unsaturated Zn for strengthened carrier radiative recombination and removing the superabundant oleic acid through ligand exchange for efficient carrier transport. As a result, the merits of bromide decoration benefit a large increase in photoluminescence quantum yield (PLQY) from 39.7% to 86.2% at the wavelength of 443 nm, as well as a great enhancement of the device performance with over sevenfold improvement in external quantum efficiency (EQE) from 0.74% to 5.46% and a distinct decrease in turn‐on voltage from 6.7 to 5.9 V. Consequently, this work contributes an effective approach of the multi‐shelled QD surface decoration toward enhanced QLED performance.
Microfluidic 3D Printing of Emulsion Ink for Engineering Porous Functionally Graded Materials
Authors: Marcotulli Martina , Tirelli Maria Celeste , Volpi Marina , Jaroszewicz Jakub , Scognamiglio Chiara , Kasprzycki Piotr , Karnowski Karol , Święszkowski Wojciech , Ruocco Giancarlo , Costantini Marco , Cidonio Gianluca , Barbetta Andrea 
Published: December 2022

AbstractIn the last decade, 3D printing systems have greatly evolved both in terms of processable materials and printing resolutions, becoming a top seed technology for many academic and industrial applications. Nevertheless, manufacturing polymeric materials characterized by a trabecular porosity and functionally graded architecture—where both the local porosity and chemical composition of the matrix change in the 3D space—through additive platforms remains an open technical challenge. In this study, a 3D extrusion printing strategy to tackle this problem is presented. The proposed systems are based on a flow‐focusing microfluidic printing head—to continuously generate oil‐in‐water emulsion inks—and on an agarose fluid–gel used as a temporary support bath for the deposition of the photo‐curable emulsion inks. It is demonstrated that through this strategy one can design a priori and build with high accuracy both discontinuous and continuous functionally graded polymeric foams, where both the density and composition of the materials could be varied independently within arbitrarily complex 3D architectures. This study provides new means for the synthesis of microporous, polymeric FGMs which could find applications ranging from interface tissue engineering to automotive and construction industries.
Tunable and Thermally Stable Luminescence from Polycyclic Aromatic Hydrocarbons Confined in a Zeolitic Imidazolate Framework
Authors: Tu Min , de Jong Flip , Martín Cristina , Reinsch Helge , Rodríguez‐Hermida Sabina , Meulemans Arne , Fron Eduard , Escudero Daniel , Van der Auweraer Mark , Hofkens Johan , Ameloot Rob 
Published: December 2022

AbstractMetal–organic frameworks (MOFs) can provide a variety of nanocompartments for the confinement of guest molecules. Furthermore, the emissions of fluorescent molecules can be tuned by confinement. In this study, a solvent‐free “bottle‐around‐ship” method is used to encapsulate perylene and 9,10‐dimethylanthracene, two polycyclic aromatic hydrocarbons, in the MOF ZIF‐8. Luminescence color tuning is achieved, including white‐light emission, when controlling the loading of only a single type of guest. Photophysical analysis suggests that the variations in luminescence result from various guest arrangements in the nanocompartments, as well as host–guest interactions. Because of the tight confinement of the guests, this host–guest system displays excellent luminescence thermal stability.
Is it worth it? A qualitative analysis of the impact of medical education fellowships on careers
Authors: Jordan Jaime , Gisondi Michael A. , Buckanavage Jack , Diller David , Pedigo Ryan , Ahn James , Riddell Jeffrey 
Published: December 2022

AbstractObjectivesMedical education fellowships provide training in teaching, assessment, educational program administration, and scholarship. The longitudinal impact of this training is unknown. The objective of this study was to explore the impact of medical education fellowships on the careers of graduates.MethodsThe authors performed a qualitative study with a constructivist–interpretivist paradigm using semistructured interviews in 2021. The authors used a purposeful randomized stratified sampling strategy of graduates to ensure diversity of representation (gender, region, fellowship duration, and career stage). Two researchers independently analyzed interview transcriptions using a modified grounded theory approach.ResultsThe authors interviewed 10 graduates and identified three overarching concepts: motivations for pursuing fellowship, benefits of training, and drivers of career development. Graduates sought training because of their desire for growth and career preparation and at the advice of mentors. Fellowships provided knowledge and skills in a structured learning environment, supported by mentors and a collaborative community. Fellowship training shaped the careers of graduates by increasing their self‐efficacy, enhancing their outcome expectations, refining their goals, and influencing their professional identity formation. They acquired expertise that prepared them for jobs, developed credibility, felt competitive in the job market, anticipated successful promotion, reached for greater goals, broadened their educational worldview, and evolved their professional identity as a result of fellowship training.ConclusionsFellowship training in medical education provides knowledge and skills, a structured learning environment, and important relationships that shape the careers of graduates by impacting their self‐efficacy, outcome expectations, goal creation, and professional identity formation.
Metal–Organic Frameworks as Electrocatalysts
Authors: Peng Yong , Sanati Soheila , Morsali Ali , García Hermenegildo 
Published: December 2022

AbstractTransition metal complexes are well‐known homogeneous electrocatalysts. In this regard, metal–organic frameworks (MOFs) can be considered as an ensemble of transition metal complexes ordered in a periodic arrangement. In addition, MOFs have several additional positive structural features that make them suitable for electrocatalysis, including large surface area, high porosity, and high content of accessible transition metal with exchangeable coordination positions. The present review describes the current state in the use of MOFs as electrocatalysts, both as host of electroactive guests and their direct electrocatalytic activity, particularly in the case of bimetallic MOFs. The field of MOF‐derived materials is purposely not covered, focusing on the direct use of MOFs or its composites as electrocatalysts. Special attention has been paid to present strategies to overcome their poor electrical conductivity and limited stability.
Durable Electrocatalytic Reduction of Nitrate to Ammonia over Defective Pseudobrookite Fe2TiO5Nanofibers with Abundant Oxygen Vacancies
Authors: Du Hongting , Guo Haoran , Wang Kaike , Du Xiangning , Beshiwork Bayu Admasu , Sun Shengjun , Luo Yongsong , Liu Qian , Li Tingshuai , Sun Xuping 
Published: December 2022

AbstractWe propose the pseudobrookite Fe2TiO5nanofiber with abundant oxygen vacancies as a new electrocatalyst to ambiently reduce nitrate to ammonia. Such catalyst achieves a large NH3yield of 0.73 mmol h−1 mg−1cat.and a high Faradaic Efficiency (FE) of 87.6 % in phosphate buffer saline solution with 0.1 M NaNO3, which is lifted to 1.36 mmol h−1 mg−1cat.and 96.06 % at −0.9 V vs. RHE for nitrite conversion to ammonia in 0.1 M NaNO2. It also shows excellent electrochemical durability and structural stability. Theoretical calculation reveals the enhanced conductivity of this catalyst and an extremely low free energy of −0.28 eV for nitrate adsorption at the presence of vacant oxygen.
Die Bindung von Cyanid an [FeFe]‐Hydrogenasen stabilisiert die alternative Konfiguration des Protonentransferpfads
Authors: Duan Jifu , Hemschemeier Anja , Burr David J. , Stripp Sven T. , Hofmann Eckhard , Happe Thomas 
Published: December 2022

AbstractHydrogenasen sind H2‐umsetzende Metalloenzyme und enthalten katalytische Kofaktoren, deren Eisenionen durch biologisch ungewöhnliche Kohlenmonoxid‐ (CO) und Cyanid‐ (CN−) Liganden koordiniert sind. Externes CO und CN−hemmt Hydrogenasen jedoch. Der molekulare Mechanismus der Bindung von CN−an [FeFe]‐Hydrogenasen ist unbekannt. In dieser Studie präsentieren wir Kristallstrukturen der mit CN−behandelten [FeFe]‐Hydrogenase CpI ausClostridium pasteurianum. Auf Grund der hohen Auflösung von 1.39 Å können wir die intrinsischen CO‐ und CN−‐Liganden voneinander unterscheiden. Wir zeigen, dass externes CN−die offene Bindestelle des Kofaktors besetzt, an die auch externes CO bindet. Im Gegensatz zu anderen Inhibitoren zeigen die CN−‐behandelten Kristalle Konformationsänderungen konservierter Reste des Protonentransferpfads, die einen direkten Austausch von Protonen zwischen den Aminosäuren E279 und S319 ermöglichen. Diese Konformation wurde als notwendig für einen effizienten Protonentransfer vorgeschlagen, doch wurde sie bisher nicht strukturell nachgewiesen.
The interaction of loading mode and humidity on the properties degradation of an epoxy adhesive subjected to strength, fracture, and fatigue tests
Authors: de Castro Lopes Frederico V. B. , Akhavan‐Safar Alireza , Carbas Ricardo J. C. , Marques Eduardo A. S. , Goyal Rakesh , Jennings Justin , da Silva Lucas F. M. 
Published: December 2022

AbstractHygrothermal aging has a significant impact on the performance of adhesives and bonded joints. However, despite extensive investigations into the aging effect of bonded structures, there is still limited knowledge on how aging affects joint performance as a function of the loading type and the load angle. Accordingly, in this study, an epoxy adhesive was tested under different loading types/angles including tensile and shear standard strength tests, mode I and mode II fracture tests, and fatigue and static Arcan tests. All these experiments were performed for both aged and unaged conditions. To understand the influence of loading angle on the failure response of aged bonded joints, Arcan samples were subjected to mixed mode loading conditions as well. A fractography analysis was conducted to provide a better understanding of the failure mechanism of aged samples loaded at different modes. Based on these results, it was found that mode I (tensile loading conditions) is more sensitive to the aging conditions than mode II (shearing) for all loading types (strength, fracture, and fatigue tests). The influence of moisture on fracture toughness was however less relevant than the strength. The results also showed that for the same loading mode and for the same Arcan joints, the fatigue strength is significantly more degraded by the aging conditions than the static strength.
Structure and properties of new biodegradable elastomers composed of poly(ethylene succinate)‐based poly(ether ester)s and poly(lactic acid)
Authors: He Zhaohui , Feng Yinbiao , Wang Cong , Yang Junjiao , Tan Tianwei , Yang Jing 
Published: December 2022

AbstractThe green sustainability of the plastic industry always gives impetus to develop the biobased and biodegradable polymers for substituting chemical products. In this study, aliphatic poly(ethylene succinate)‐based poly(ether ester)s (PES‐based PEE) were firstly explored via one pot/two‐component industrial melt polycondensation of succinic acid (SA) and ethylene glycol (EG) in the catalytic combination of titanium tetraisopropoxide (TTP) and methylsulfonic acid (MSA). Their thermal properties and mechanical behavior were analyzed in detail. Based on complementary properties of PES‐based PEEs and poly(lactic acid) (PLA) in the aspect of the flexibility and ductility, the copolymerization of poly(ethylene succinate)‐poly(diethylene glycol succinate) (PES‐PDES) with PLA with low molecular weight was further systematically elaborated and characterized. The results from differential scanning calorimeter showed all the copolymers with different LA contents were amorphous without the melting temperatures. Only oneαrelaxation revealed by DMA indicated PES‐PDES and PLA segments were random distribution and compatible. The monotonical decrease in glass transition temperatures (Tgs) hinted the mobility enhancement of the copolymers with increasing PES‐PDES contents. All the copolymers PES‐PDES‐PLAs exhibited relatively high thermal degradation temperature withT5%above 280°C. The mechanical properties and degradable behavior of the copolymers were significantly ameliorated by changing the composition fractions of PES‐PDES and PLA in the architecture.