bluuebunny/crossref_metadata_2025_split huggingface dataset:
Light‐Assisted Charge Propagation in Networks of Organic Semiconductor Crystallites on Hexagonal Boron Nitride
Authors: Matković Aleksandar , Genser Jakob , Kratzer Markus , Lüftner Daniel , Chen Zhongrui , Siri Olivier , Puschnig Peter , Becker Conrad , Teichert Christian 
Published: August 2019

AbstractIntroducing organic semiconductors as additional building blocks into heterostructures of 2D materials widens the horizon of their applications. Organic molecules can form self‐assembled and self‐aligned crystalline nanostructures on 2D materials, resulting in well‐defined interfaces that preserve the intrinsic properties of both constituents. Thus, organic molecules add unique capabilities to van der Waals heterostructures that have no analogues in inorganic matter. This study explores light‐assisted charge propagation in organic semiconductor networks of quasi‐1D needle‐like crystallites, epitaxially grown on insulating hexagonal boron nitride. Electrostatic force microscopy is employed to demonstrate that upon external illumination it is possible to change the conductivity of organic crystallites by more than two orders of magnitude. Furthermore, by exploiting the highly anisotropic optical properties of the organic nanoneedles, a selective charge propagation along the crystallites is triggered that matches the orientation of the molecular backbones with the incident light's polarization direction. These results demonstrate the possibility to use a “light‐gate” to switch on the conductivity of organic nanostructures and even to guide the charge propagation along desired directions in self‐assembled crystallite networks.
Efficient Charge Carrier Injection and Balance Achieved by Low Electrochemical Doping in Solution‐Processed Polymer Light‐Emitting Diodes
Authors: Yan Hao , Limbu Saurav , Wang Xuhua , Nightingale James , Hamilton Iain , Wade Jessica , Kwon Sooncheol , Lee Kwanghee , Kim Ji‐Seon 
Published: August 2019

AbstractCharge carrier injection and transport in polymer light‐emitting diodes (PLEDs) is strongly limited by the energy level offset at organic/(in)organic interfaces and the mismatch in electron and hole mobilities. Herein, these limitations are overcome via electrochemical doping of a light‐emitting polymer. Less than 1 wt% of doping agent is enough to effectively tune charge injection and balance and hence significantly improve PLED performance. For thick single‐layer (1.2 µm) PLEDs, dramatic reductions in current and luminance turn‐on voltages (VJ = 11.6 V from 20.0 V and VL = 12.7 V from 19.8 V with/without doping) accompanied by reduced efficiency roll‐off are observed. For thinner (<100 nm) PLEDs, electrochemical doping removes a thickness dependence on VJ and VL, enabling homogeneous electroluminescence emission in large‐area doped devices. Such efficient charge injection and balance properties achieved in doped PLEDs are attributed to a strong electrochemical interaction between the polymer and the doping agents, which is probed by in situ electric‐field‐dependent Raman spectroscopy combined with further electrical and energetic analysis. This approach to control charge injection and balance in solution‐processed PLEDs by low electrochemical doping provides a simple yet feasible strategy for developing high‐quality and efficient lighting applications that are fully compatible with printing technologies.
Structurally Stable Manganese Alkoxide Films Grown by Hybrid Molecular Layer Deposition for Electrochemical Applications
Authors: Bergsman David S. , Baker Jon G. , Closser Richard G. , MacIsaac Callisto , Lillethorup Mie , Strickler Alaina L. , Azarnouche Laurent , Godet Ludovic , Bent Stacey F. 
Published: August 2019

AbstractHybrid molecular layer deposition (MLD) has significant potential for the creation of ultrathin electrochemically active materials, due to its ability to combine organic and inorganic species to modulate film properties. However, only a limited number of hybrid MLD processes are demonstrated with electrochemically relevant elements, such as manganese. Here, a “manganicone” manganese hybrid MLD chemistry is developed using the precursors bis(ethylcyclopentadienyl)manganese and ethylene glycol. The resulting manganese alkoxide coordination networks are shown to have many interesting properties, including the ability to seamlessly fill high aspect ratio vias and the chemical conversion into manganese carboxylate in air over several hours at room temperature. Linear, self‐saturating growth is reported. Importantly, hybrid manganicone films annealed to 480 °C in air demonstrate a greater stability to restructuring during electrochemical testing than their inorganic counterparts grown by atomic layer deposition, without reducing the activity of the reactive sites on the manganese surface. Thus, hybrid manganese films grown by MLD have significant promise for use as catalysts for the oxygen evolution reaction and as electrodes in thin film batteries.
Strong Electronic Interaction of Amorphous Fe2O3 Nanosheets with Single‐Atom Pt toward Enhanced Carbon Monoxide Oxidation
Authors: Chen Wenlong , Ma Yanling , Li Fan , Pan Lei , Gao Wenpei , Xiang Qian , Shang Wen , Song Chengyi , Tao Peng , Zhu Hong , Pan Xiaoqing , Deng Tao , Wu Jianbo 
Published: August 2019

AbstractPlatinum‐based catalysts are critical to several chemical processes, but their efficiency is not satisfying enough in some cases, because only the surface active‐site atoms participate in the reaction. Henceforth, catalysts with single‐atom dispersions are highly desirable to maximize their mass efficiency, but fabricating these structures using a controllable method is still challenging. Most previous studies have focused on crystalline materials. However, amorphous materials may have enhanced performance due to their distorted and isotropic nature with numerous defects. Here reported is the facile synthesis of an atomically dispersed catalyst that consists of single Pt atoms and amorphous Fe2O3 nanosheets. Rational control can regulate the morphology from single atom clusters to sub‐nanoparticles. Density functional theory calculations show the synergistic effect resulted from the strong binding and stabilization of single Pt atoms with the strong metal‐support interaction between the in situ locally anchored Pt atoms and Fe2O3 lead to a weak CO adsorption. Moreover, the distorted amorphous Fe2O3 with O vacancies is beneficial for the activation of O2, which further facilitates CO oxidation on nearby Pt sites or interface sites between Pt and Fe2O3, resulting in the extremely high performance for CO oxidation of the atomic catalyst.
Deciphering Limitations to Meet Highly Stable Bio‐Hybrid Light‐Emitting Diodes
Authors: Fernández‐Luna Verónica , Sánchez‐de Alcázar Daniel , Fernández‐Blázquez Juan P. , Cortajarena Aitziber L. , Coto Pedro B. , Costa Rubén D. 
Published: August 2019

AbstractColor down‐converting filters with fluorescent proteins (FPs) embedded in a polymer matrix have led to new bio‐hybrid light‐emitting diodes (Bio‐HLEDs), featuring stabilities of 100 h and <1 min at low and high applied currents, respectively. Herein, the FP deactivation mechanism in Bio‐HLEDs at high driving currents is deciphered. Primarily, the nonradiative energy relaxation of FPs upon excitation promotes the release of excess energy to the polymer matrix, reaching 60 °C and, in turn, a significant thermal emission quenching. This is circumvented by changing the device architecture, achieving stabilities of >300 h at high driving currents. Here, the photoinduced deactivation mechanism takes place, consisting of a slow and reversible partial dehydration followed by a quick and irreversible deactivation of the highly emissive ionic form. This is supported by steady‐state/time‐resolved emission, circular dichroism, and electrochemical impedance spectroscopic techniques. Overall, the limitations of Bio‐HLEDs concerning matrix, buffers, device design, and FP stability are highlighted as key aspects to achieve efficient and stable devices.
Unidirectional Liquid Manipulation Via an Integrated Mesh with Orthogonal Anisotropic Slippery Tracks
Authors: Li Peng , Cao Moyuan , Bai Haoyu , Zhao Tianhong , Ning Yuzhen , Wang Xinsheng , Liu Kesong , Jiang Lei 
Published: August 2019

AbstractThe rational manipulation of fluid behavior by functional interfaces plays an indispensable role in the development of advanced materials and devices involving liquid/solid interactions. Previous examples of the liquid “diode” that allows fluid penetration in only one direction rely mainly on the remarkable wettability gradient/contrast. Inspired by the wetting phenomena of the rice leaf and the Pitcher plant, an integrated mesh with orthogonal anisotropic slippery tracks (IMOAS) is presented here that can realize similar unidirectional droplet penetration using a distinct mechanism. The unidirectional droplet penetration can be conveniently switched via the 90° rotation of the IMOAS, showing a highly controllable liquid manipulation. The droplet tends to slip on the surface, which can maximize the contact area between the liquid and the tracks, and complies with the principle of the lowest surface energy. Based on this unique liquid controlling strategy, droplet manipulation of the IMOAS during fog harvesting and droplet self‐regulation has been conducted to illustrate its potential applications. The current design could aid the understanding of liquid unidirectional penetration and unlock additional possibilities for the optimization of fluid‐related systems.
Biomass Valorization via Paired Electrosynthesis Over Vanadium Nitride‐Based Electrocatalysts
Authors: Li Suiqin , Sun Xiang , Yao Zihao , Zhong Xing , Cao Yongyong , Liang Yulin , Wei Zhongzhe , Deng Shengwei , Zhuang Guilin , Li Xiaonian , Wang Jianguo 
Published: August 2019

AbstractPaired electrosynthesis is a promising technology with the potential to generate value‐added products at both electrodes in a cost‐effective manner. Herein, 3D vanadium nitride (VN) and Pd/VN hollow nanospheres are successfully fabricated and coupled to carry out simultaneous electrocatalytic oxidation (ECO) and electrocatalytic hydrogenation (ECH) of 5‐hydroxymethylfurfural (HMF) into 2, 5‐furandicarboxylic acid (FDCA) and 2,5‐bishydroxymethyl‐tetrahydrofuran (DHMTHF), respectively. VN shows excellent ECO performance with high HMF conversion (≥98%), FDCA selectivity (≥96%), and faradaic efficiency (≥84%) after a stability test, and Pd/VN achieves high ECH selectivity for DHMTHF at ≥88% and an HMF conversion of ≥90%, with a faradaic efficiency of ≥86%. VN and Pd/VN incorporated into a membrane electrode assembly in a paired electrolysis system shows potential for large‐scale biomass conversion and upgrading. Theoretical calculations reveal that the higher performance of VN for the production of ECO can be attributed to its lower d‐band center level relative to the Fermi level compared to that of V2O5, which favors HMF chemisorption and activation. This study paves the way for developing paired electrosynthesis technologies with the potential for biomass utilization and energy conversion.
Treatment of Critical‐Sized Calvarial Defects in Rats with Preimplanted Transplants
Authors: Charbonnier Baptiste , Abdulla Mohamed , Gorgy Andrew , Shash Hani , Zhang Zishuai , Gbureck Uwe , Harvey Ed , Makhoul Nicholas , Gilardino Mirko , Barralet Jake 
Published: August 2019

AbstractThe local environment and the defect features have made the skull one of the most difficult regions to repair. Finding alternative strategies to repair large cranial defects, thereby avoiding the current limitations of autograft or polymeric and ceramic prostheses constitute an unmet need. In this study, the regeneration of an 8 mm critical‐sized calvarial defect treated by autograft or by a monetite scaffold directly placed in the defect or preimplanted (either cranial bone transplant or subcutaneous pocket) and then transplanted within the bone defect is compared. The data reveal that transplantation of preimplanted monetite transplant scaffolds greatly improves the skull vault closure compared to subcutaneously preimplanted or directly placed materials. Autografts, while clearly filling the defect volume with bone appear effective since bone volume inside the defect volume is obviously high, but are not well fused to the skull. The preimplantation site has a large influence on the regeneration of the defect. Transplantation of induced bone inside materials has the potential to reduce the need for autograft harvest without damaging the skeleton. This first demonstration indicates that cranial repair may be possible without recourse to bioactives or cultured cell therapies.
Surfactant‐Stripped Micelles for NIR‐II Photoacoustic Imaging through 12 cm of Breast Tissue and Whole Human Breasts
Authors: Chitgupi Upendra , Nyayapathi Nikhila , Kim Jeesu , Wang Depeng , Sun Boyang , Li Changning , Carter Kevin , Huang Wei‐Chiao , Kim Chulhong , Xia Jun , Lovell Jonathan F. 
Published: August 2019

AbstractSurfactant‐stripped micelles are formed from a commercially available cyanine fluoroalkylphosphate (CyFaP) salt dye and used for high contrast photoacoustic imaging (PAI) in the second near‐infrared window (NIR‐II). The co‐loading of Coenzyme Q10 into surfactant‐stripped CyFaP (ss‐CyFaP) micelles improves yield, storage stability, and results in a peak absorption wavelength in the NIR‐II window close to the 1064 nm output of Nd‐YAG lasers used for PAI. Aqueous ss‐CyFaP dispersions exhibit intense NIR‐II optical absorption, calculated to be greater than 500 at 1064 nm. ss‐CyFaP is detected through 12 cm of chicken breast tissue with PAI. In preclinical animal models, ss‐CyFaP is visualized in draining lymph nodes of rats through 3.1 cm of overlaid chicken breast tissue. Following intravenous administration, ss‐CyFaP accumulates in neoplastic tissues of mice and rats bearing orthotopic mammary tumors without observation of acute toxic side effects. ss‐CyFaP is imaged through whole compressed human breasts in three female volunteers at depths of 2.6–5.1 cm. Taken together, these data show that ss‐CyFaP is an accessible contrast agent for deep tissue PAI in the NIR‐II window.
Adaptable and Reprogrammable Surfaces
Authors: Goldmann Anja S. , Boase Nathan R. B. , Michalek Lukas , Blinco James P. , Welle Alexander , Barner‐Kowollik Christopher 
Published: August 2019

AbstractEstablishing control over chemical reactions on interfaces is a key challenge in contemporary surface and materials science, in particular when introducing well‐defined functionalities in a reversible fashion. Reprogrammable, adaptable and functional interfaces require sophisticated chemistries to precisely equip them with specific functionalities having tailored properties. In the last decade, reversible chemistries—both covalent and noncovalent—have paved the way to precision functionalize 2 or 3D structures that provide both spatial and temporal control. A critical literature assessment reveals that methodologies for writing and erasing substrates exist, yet are still far from reaching their full potential. It is thus critical to assess the current status and to identify avenues to overcome the existing limitations. Herein, the current state‐of‐the‐art in the field of reversible chemistry on surfaces is surveyed, while concomitantly identifying the challenges—not only synthetic but also in current surface characterization methods. The potential within reversible chemistry on surfaces to function as true writeable memories devices is identified, and the latest developments in readout technologies are discussed. Finally, we explore how spatial and temporal control over reversible, light‐induced chemistries has the potential to drive the future of functional interface design, especially when combined with powerful laser lithographic applications.
High Signal‐to‐Noise Chemical Sensors Based on Compensated Organic Transistor Circuits
Authors: Chu Yingli , Li Hui , Huang Jia , Katz Howard E. 
Published: August 2019

AbstractOperational stability and sensitivity are key issues for the practical application of organic field‐effect‐transistor (OFET)‐based sensors. Instability over time due to intrinsic device bias stress and conductance drift induced by the ambient environment can obscure responses to analytes of interest. These instabilities are well‐known hindrances to the practical application of OFET sensors. It is demonstrated for the first time that an innovative and simple two‐OFET circuit design can effectively compensate the drifts originating from bias stress and/or the environment while maintaining chemical sensitivity and increasing signal‐to‐noise ratio. This is enabled by illumination of one photosensitive OFET to compensate the drift of the other chemical‐sensing OFET, though in principle a pair of OFETs with opposing drifts generated by any mechanism could be used. The circuit, compared with individual OFET‐based sensors, achieves significantly increased environmental stability, and its enhanced response to chemical vapors is also demonstrated by detecting the representative pollutants nitrogen dioxide (NO2) and ammonia (NH3). This shows that OEFTs with drifts being compensated by any mechanism can lead to stabilized sensor circuits.
Dominance of Exciton Lifetime in the Stability of Phosphorescent Dyes
Authors: Ha Dong‐Gwang , Tiepelt Jan , Fusella Michael A. , Weaver Michael S. , Brown Julie J. , Einzinger Markus , Sherrott Michelle C. , Van Voorhis Troy , Thompson Nicholas J. , Baldo Marc A. 
Published: August 2019

AbstractOrganic light‐emitting devices (OLEDs) are widely used for mobile displays, but the relatively short lifetime of blue OLEDs remains a challenge in many applications. Typically, instability is viewed as a material‐specific chemical degradation problem. It is known to be alleviated by reducing the operating current or otherwise decreasing the exciton density. It is shown here that this view is incomplete. For archetypical phosphorescent materials, it is observed that the dependence of photostability on the triplet exciton lifetime follows a cubic power law, steeper than its dependence on exciton density. It is demonstrated that the triplet exciton lifetime not only determines the energy stored within an OLED, it also determines the loss in luminescence by controlling the yield of quenching by defects. The dominant role of the triplet exciton lifetime suggests that the stability of the best OLED materials can be significantly improved via rapid extraction of the energy stored in triplet excitons.
Enantioselective Conjugate Azidation of α,β‐Unsaturated Ketones under Bifunctional Organocatalysis by Direct Activation of TMSN3
Authors: Humbrías‐Martín Jorge , Pérez‐Aguilar M. Carmen , Mas‐Ballesté Rubén , Dentoni Litta Antonella , Lattanzi Alessandra , Della Sala Giorgio , Fernández‐Salas Jose A. , Alemán José 
Published: August 2019

AbstractAn enantioselective organocatalytic conjugate azidation of α,β‐unsaturated ketones is presented. A bifunctional organocatalyst activates TMSN3, triggering the nucleophilic addition of the azido group to enones in absence of external promoters and avoiding the direct use or the pre‐formation of highly toxic and explosive hydrazoic acid. This protocol proceeds with excellent enantiocontrol under mild conditions. DFT calculations and mechanistic trials have been performed in order to demonstrate the direct activation performed by the bifunctional organocatalyst.magnified image
Depression as a Risk Factor for Impulse Control Disorders in Parkinson Disease
Authors: Marín‐Lahoz Juan , Sampedro Frederic , Martinez‐Horta Saül , Pagonabarraga Javier , Kulisevsky Jaime 
Published: August 2019

ObjectiveTo longitudinally evaluate the role of depression in the development of impulse control disorders (ICDs) in Parkinson disease (PD) patients.MethodsUsing data from the Parkinson's Progression Markers Initiative, we included PD patients without ICDs at baseline according to the Questionnaire for Impulsive‐Compulsive Disorders in Parkinson's Disease (QUIP). Patients were prospectively evaluated first quarterly and then biannually. Development of an ICD was defined as an increase in QUIP scores during follow‐up. Using survival proportional hazard models, we studied the effect of baseline depression on ICD risk. We also evaluated this effect controlling for dopamine agonist use as a time‐dependent variable and for other potential confounders.ResultsAmong 354 patients, 68 were depressed at baseline. The median follow‐up was 4.08 years. Depression at baseline was associated with higher ICD risk (hazard ratio [HR] = 1.96, 95% confidence interval [CI] = 1.32–2.9, p < 0.001). This risk remained significant after controlling for dopamine agonist use (HR = 1.97, 95% CI = 1.33–2.9, p < 0.001), which was also independently linked to ICD development (HR = 1.87, 95% CI = 1.3–2.7, p < 0.001). Therefore, depressed patients faced an even higher ICD risk when receiving dopamine agonists. Controlling for multiple potential confounders did not alter these results.InterpretationDepression predisposes to the development of ICDs in PD. This risk is magnified by dopamine agonists. Dopamine agonists should thus be used cautiously in depressed PD patients. ANN NEUROL 2019;86:762–769
Polymer complexes. LXXVIII. Synthesis and characterization of supramolecular uranyl polymer complexes: Determination of the bond lengths of uranyl ion in polymer complexes
Authors: Diab M.A. , Nozha S.G. , El‐Sonbati A.Z. , El‐Mogazy M.A. , Morgan Sh.M. 
Published: August 2019

The UO2(II) polymer complexes (1–5) of azo dye ligands 5(4`‐derivatives phenylazo)‐8‐hydroxy‐7‐quinolinecarboxaldehyde (HLx) were prepared and characterized by elemental analysis, 1H NMR, IR spectra, thermal analysis and X‐ray diffraction analysis (XRD). The molecular geometrical structures and quantum chemical of the ligands (HLx) and their tautomeric forms (D and G) were calculated. Molecular docking between the HLx ligands and their tautomeric form with two receptors of the breast cancer (1JNX) and the prostate cancer (2Q7K) was discussed. From the histogram of the HOMO–LUMO energy gap (ΔE) and the estimated free energy of binding of the receptors of prostate cancer (2Q7K) and breast cancer (1JNX) for the ligands (HLx), it is observed that the ΔE values of the ligands (HLx) increases in the order HL2 < HL3 < HL4 < HL1 < HL5. The electronic structures and coordination were determined from a framework for the modeling of the formed polymer complexes. From the IR spectra of the polymer complexes, the symmetric stretching frequency υ3 values of UO22+ were used for the determination of the force constant (FU‐O (in 10−8 N/Ả)) and the bond length (RU‐O (Ả)) of the U–O bond by using Wilson, G. F. matrix method, McGlynn & Badger's formula and El‐Sonbati equations. The plot of the bond distance rU‐O (r1, r2, r3, and rt) vs. υ3 was showed straight lines with increase in the value of υ3 and decrease in rU‐O.