pinecone/core-2020-05-10-deduplication huggingface dataset:
Electronic Structure of Low-Temperature Solution-Processed Amorphous Metal Oxide Semiconductors for Thin-Film Transistor Applications

The electronic structure of low temperature, solution-processed indium–zinc oxide thin-film transistors is complex and remains insufficiently understood. As commonly observed, high device performance with mobility >1 cm2 V−1 s−1 is achievable after annealing in air above typically 250 °C but performance decreases rapidly when annealing temperatures ≤200 °C are used. Here, the electronic structure of low temperature, solution-processed oxide thin films as a function of annealing temperature and environment using a combination of X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, and photothermal deflection spectroscopy is investigated. The drop-off in performance at temperatures ≤200 °C to incomplete conversion of metal hydroxide species into the fully coordinated oxide is attributed. The effect of an additional vacuum annealing step, which is beneficial if performed for short times at low temperatures, but leads to catastrophic device failure if performed at too high temperatures or for too long is also investigated. Evidence is found that during vacuum annealing, the workfunction increases and a large concentration of sub-bandgap defect states (re)appears. These results demonstrate that good devices can only be achieved in low temperature, solution-processed oxides if a significant concentration of acceptor states below the conduction band minimum is compensated or passivated by shallow hydrogen and oxygen vacancy-induced donor levels.The authors acknowledge funding from the European Union Seventh Framework Programme (FP7/2007–2013) under Grant Agreement No.°263042. J.S. wants to thank the Engineering and Physical Sciences Research Council and the A.G. Leventis Foundation for funding.This is the final version of the article. It first appeared at http://onlinelibrary.wiley.com/doi/10.1002/adfm.201404375/ful
A Decaheme Cytochrome as a Molecular Electron Conduit in Dye-Sensitized Photoanodes

In nature, charge recombination in light-harvesting reaction centers is minimized by efficient charge separation. Here, it is aimed to mimic this by coupling dye-sensitized TiO2 nanocrystals to a decaheme protein, MtrC from Shewanella oneidensis MR-1, where the 10 hemes of MtrC form a ≈7-nm-long molecular wire between the TiO2 and the underlying electrode. The system is assembled by forming a densely packed MtrC film on an ultra-flat gold electrode, followed by the adsorption of approximately 7 nm TiO2 nanocrystals that are modified with a phosphonated bipyridine Ru(II) dye (RuP). The step-by-step construction of the MtrC/TiO2 system is monitored with (photo)electrochemistry, quartz-crystal microbalance with dissipation (QCM-D), and atomic force microscopy (AFM). Photocurrents are dependent on the redox state of the MtrC, confirming that electrons are transferred from the TiO2 nanocrystals to the surface via the MtrC conduit. In other words, in these TiO2/MtrC hybrid photodiodes, MtrC traps the conduction-band electrons from TiO2 before transferring them to the electrode, creating a photobioelectrochemical system in which a redox protein is used to mimic the efficient charge separation found in biological photosystems.This work was supported by the BBSRC (grants BB/K009753/1, BB/K010220/1, and BB/K009885/1), the EPSRC (EP/H00338X/2; PhD studentship to Emma Ainsworth), the Christian Doppler Research Association and the OMV Group. The authors appreciate Dr. Liang Shi (PNNL) and Dr. Marcus Edwards (UEA) for providing the S. oneidensis strain and the protocol allowing for purification of MtrC.This is the final published version of the article. It was originally published in Advanced Functional Materials (Hwang ET, Sheikh K, Orchard KL, Hojo D, Radu V, Lee C-Y, Ainsworth E, Lockwood C, Gross MA, Adschiri T, Reisner E, Butt JN, Jeuken LJC, Advanced Functional Materials 2015, 25, 2308–2315, doi: 10.1002/adfm.201404541) http://dx.doi.org/10.1002/adfm.201404541
In situ production of biofunctionalized few-layer defect-free microsheets of graphene

Biological interfacing of graphene has become crucial to improve its biocompatibility, dispersability, and selectivity. However, biofunctionalization of graphene without yielding defects in its sp²-carbon lattice is a major challenge. Here, a process is set out for biofunctionalized defect-free graphene synthesis through the liquid phase ultrasonic exfoliation of raw graphitic material assisted by the self-assembling fungal hydrophobin Vmh2. This protein (extracted from the edible fungus Pleurotus ostreatus) is endowed with peculiar physicochemical properties, exceptional stability, and versatility. The unique properties of Vmh2 and, above all, its superior hydrophobicity, and stability allow to obtain a highly concentrated (≈440-510 μg mL⁻¹) and stable exfoliated material (ζ-potential, +40/+70 mV). In addition controlled centrifugation enables the selection of biofunctionalized few-layer defect-free micrographene flakes, as assessed by Raman spectroscopy, atomic force microscopy, scanning electron microscopy, and electrophoretic mobility. This biofunctionalized product represents a high value added material for the emerging applications of graphene in the biotechnological field such as sensing, nanomedicine, and bioelectronics technologies
Continuously Tunable Emission in Inverted Type-I CdS/
CdSe Core/Crown Semiconductor Nanoplatelets

Cataloged from PDF version of article.The synthesis and unique tunable optical properties of core/crown nanoplatelets having an inverted Type-I heterostructure are presented. Here, colloidal 2D CdS/CdSe heteronanoplatelets are grown with thickness of four monolayers using seed-mediated method. In this work, it is shown that the emission peak of the resulting CdS/CdSe heteronanoplatelets can be continuously spectrally tuned between the peak emission wavelengths of the core only CdS nanoplatelets (421 nm) and CdSe nanoplatelets (515 nm) having the same vertical thickness. In these inverted Type-I nanoplatelets, the unique continuous tunable emission is enabled by adjusting the lateral width of the CdSe crown, having a narrower bandgap, around the core CdS nanoplatelet, having a wider bandgap, as a result of the controlled lateral quantum confinement in the crown region additional to the pure vertical confinement. As a proof-of-concept demonstration, a white light generation is shown by using color conversion with these CdS/CdSe heteronanoplatelets having finely tuned thin crowns, resulting in a color rendering index of 80. The robust control of the electronic structure in such inverted Type-I heteronanoplatelets achieved by tailoring the lateral extent of the crown coating around the core template presents a new enabling pathway for bandgap engineering in solution-processed quantum wells
Liquid-Liquid Diffusion-Assisted Crystallization: A Fast and Versatile Approach Toward High Quality Mixed Quantum Dot-Salt Crystals

Cataloged from PDF version of article.Here, a new, fast, and versatile method for the incorporation of colloidal quantum dots (QDs) into ionic matrices enabled by liquid-liquid diffusion is demonstrated. QDs bear a huge potential for numerous applications thanks to their unique chemical and physical properties. However, stability and processability are essential for their successful use in these applications. Incorporating QDs into a tight and chemically robust ionic matrix is one possible approach to increase both their stability and processability. With the proposed liquid-liquid diffusion-assisted crystallization (LLDC), substantially accelerated ionic crystallization of the QDs is shown, reducing the crystallization time needed by one order of magnitude. This fast process allows to incorporate even the less stable colloids including initially oil-based ligand-exchanged QDs into salt matrices. Furthermore, in a modified two-step approach, the seed-mediated LLDC provides the ability to incorporate oil-based QDs directly into ionic matrices without a prior phase transfer. Finally, making use of their processability, a proof-of-concept white light emitting diode with LLDC-based mixed QD-salt films as an excellent color-conversion layer is demonstrated. These findings suggest that the LLDC offers a robust, adaptable, and rapid technique for obtaining high quality QD-salts
Synergistic Interaction of Dyes and Semiconductor Quantum Dots for Advanced Cascade Cosensitized Solar Cells

A new procedure for the cosensitization with quantum dots (QDs) and dyes for sensitized solar cells is reported here. Cascade cosensitization of TiO2 electrodes is obtained by the sensitization with CdS QDs and zinc phthalocyanines (ZnPcs), in which ZnPcs containing a sulfur atom are specially designed to produce a cascade injection by direct attachment to QDs. This strategy causes a double synergetic interaction. This is the differentiating point of cascade cosensitization in comparison with other approaches in which dyes with conventional functionalization are anchored to TiO2 electrodes. Cosensitization produces a panchromatic response from the visible to near-IR region already observed with other sensitization strategies. However, cascade cosensitization produces in addition a synergistic interaction between QDs and dye, that it is not merely limited to the complementary light absorption, but dye enhances the efficiency of QD sensitization acting as a passivating agent. The cascade cosensitization concept is demonstrated with using [Co(phen)3]3+/2+ redox electrolyte. The TiO2/CdS QD-ZnPc/[Co(phen)3]3+/2+ sensitized solar cell shows a large improvement of short-circuit photocurrent and open-circuit voltage in comparison with samples just sensitized with QDs. The advent of such cosensitized QD-ZnPc solar cells paves the way to extend the absorbance region of the promising QD-based solar cells and the development of a new family of molecules designed for this purpose.1) Ministerio de Economía y Competividad
2) Generalitat Valenciana
3) Universitat Jaume I
4) European FEDER funds (CTQ2011-26455, PROMETEO 2012/010, ACOMP/2013/024, ISIC/2012/008, and UJI 12I361.01/1
Disorder-Induced Localization in Crystalline Pseudo-Binary GeTe-Sb 2 Te 3 Alloys between Ge 3 Sb 2 Te 6 and GeTe

Disorder has a tremendous impact on charge transport in crystalline compounds on the pseudo-binary line between Sb2Te3 and GeTe. Directly after crystallization, the pronounced disorder on the cation sublattice renders crystalline Ge1Sb2Te4—a composition with a carrier density of the order of 1020 cm−3—an Anderson insulator. Annealing, however, induces the reduction of disorder and eventually triggers an insulator-to-metal transition. This study presents data on the electrical properties, the optical conductivity, and structural properties of the pseudo-binary compositions between Ge3Sb2Te6 and GeTe. In contrast to the preceding investigations, which rely on the annealing temperature for tuning the electrical properties, this study elucidates the impact of stoichiometry and demonstrates that the stoichiometry may be employed as an alternative control parameter for the metal-to-insulator transition. The combination of annealing temperature and stoichiometry, therefore, provides a rich playground for tailoring disorder and, as a consequence, the transport of charge
Electrostatically Directed Self-Assembly of Ultrathin Supramolecular Polymer Microcapsules

Supramolecular self-assembly offers routes to challenging architectures on the molecular and macroscopic scale. Coupled with microfluidics it has been used to make microcapsules—where a 2D sheet is shaped in 3D, encapsulating the volume within. In this paper, a versatile methodology to direct the accumulation of capsule-forming components to the droplet interface using electrostatic interactions is described. In this approach, charged copolymers are selectively partitioned to the microdroplet interface by a complementary charged surfactant for subsequent supramolecular cross-linking via cucurbit[8]uril. This dynamic assembly process is employed to selectively form both hollow, ultrathin microcapsules and solid microparticles from a single solution. The ability to dictate the distribution of a mixture of charged copolymers within the microdroplet, as demonstrated by the single-step fabrication of distinct core–shell microcapsules, gives access to a new generation of innovative self-assembled constructs.This work was supported by the Engineering Physical Sciences Research Council, Institutional Sponsorship 2012-University of Cambridge EP/K503496/1, and the Translational Grant EP/H046593/1; Y.Z. and R.P. were also funded from the Starting Investigator grant ASPiRe (No. 240629) from the European Research Council and the Isaac Newton Trust research grant No. 13.7(c). A.S. was supported by the Nano Doctoral Training Centre (NanoDTC).This is the final version of the article. It first appeared from Wiley at http://dx.doi.org/10.1002/adfm.20150107
High Quality Carbon Nanotubes on Conductive Substrates Grown at Low Temperatures

For carbon nanotubes (CNTs) to be exploited in electronic applications, the growth of high quality material on conductive substrates at low temperatures (<450°C) is required. CNT quality is known to be strongly degraded when growth is conducted on metallic surfaces, particularly at low temperatures using conventional chemical vapor deposition (CVD). Here, the production of high quality vertically-aligned CNTs at low substrate temperatures (350–440°C) on conductive TiN thin film using photo-thermal CVD is demonstrated by confining the energy required for growth to just the catalyst using an array of optical lamps and by optimizing the thickness of the TiN under-layer. The thickness of the TiN plays a crucial role in determining various properties including diameter, material quality, number of shells, and metallicity. The highest structural quality with a visible Raman D- to G-band intensity ratio as low as 0.13 is achieved for 100 nm TiN thickness grown at 420°C; a record low value for low temperature CVD grown CNTs. Electrical measurements of high density CNT arrays show the resistivity to be 1.25 × 10-2 Ω cm representing some of the lowest values reported. Finally, broader aspects of using this approach as a scalable technology for carbon nanomaterial production are also discussed
Dual targeted immunotherapy via in vivo delivery of biohybrid RNAi-peptide nanoparticles to tumour-associated macrophages and cancer cells.

Lung cancer is associated with very poor prognosis and considered one of the leading causes of death worldwide. Here, we present highly potent and selective bio-hybrid RNAi-peptide nanoparticles that can induce specific and long-lasting gene therapy in inflammatory tumour associated macrophages (TAMs), via an immune modulation of the tumour milieu combined with tumour suppressor effects. Our data prove that passive gene silencing can be achieved in cancer cells using regular RNAi NPs. When combined with M2 peptide-based targeted immunotherapy that immuno-modulates TAMs cell-population, a synergistic effect and long-lived tumour eradication can be observed along with increased mice survival. Treatment with low doses of siRNA (ED50 0.0025-0.01 mg/kg) in a multi and long-term dosing system substantially reduced the recruitment of inflammatory TAMs in lung tumour tissue, reduced tumour size (â\u88¼95%) and increased animal survival (â\u88¼75%) in mice. Our results suggest that it is likely that the combination of silencing important genes in tumour cells and in their supporting immune cells in the tumour microenvironment, such as TAMs, will greatly improve cancer clinical outcomes
ZnO nanorod arrays as electron injection layers for efficient organic light emitting diodes

Nanostructured oxide arrays have received significant attention as charge injection and collection electrodes in numerous optoelectronic devices. Zinc oxide (ZnO) nanorods have received particular interest owing to the ease of fabrication using scalable, solution processes with a high degree of control of rod dimension and density. Here, vertical ZnO nanorods as electron injection layers in organic light emitting diodes are implemented for display and lighting purposes. Implementing nanorods into devices with an emissive polymer, poly(9,9-dioctyluorene-alt-benzothiadiazole) (F8BT) and poly(9,9-di-n-octylfluorene-alt-N-(4-butylphenyl)dipheny-lamine) (TFB) as an electron blocking layer, brightness and efficiencies up to 8602 cd m−2 and 1.66 cd A−1 are achieved. Simple solution processing methodologies combined with postdeposition thermal processing are highlighted to achieve complete wetting of the nanorod arrays with the emissive polymer. The introduction of TFB to minimize charge leakage and nonradiative exciton decay results in dramatic increases to device yields and provides an insight into the operating mechanism of these devices. It is demonstrated that the detected emission originates from within the polymer layers with no evidence of ZnO band edge or defect emission. The work represents a significant development for the ongoing implementation of ZnO nanorod arrays into efficient light emitting devices
Tuneable Singlet Exciton Fission and Triplet-Triplet Annihilation in an Orthogonal Pentacene Dimer

We report fast and highly efficient intramolecular singlet exciton fission in a pentacene dimer, consisting of two covalently attached, nearly orthogonal pentacene units. Fission to triplet excitons from this ground state geometry occurs within 1 ps in isolated molecules in solution and dispersed solid matrices. The process exhibits a sensitivity to environmental polarity and competes with geometric relaxation in the singlet state, while subsequent triplet decay is strongly dependent on conformational freedom. The near orthogonal arrangement of the pentacene units is unlike any structure currently proposed for efficient singlet exciton fission and may lead to new molecular design rules.JW acknowledges financial support from Singapore MOE Tier 3 grant (MOE2014-T3-1-004). SL thanks AGS Scholarship support from the A*STAR Singapore. The work was supported by the EPSRC (grant number EP/G060738/1). We acknowledge the use of the Darwin Supercomputer of the University of Cambridge High 18 Performance Computing Service (http://www.hpc.cam.ac.uk/) and the EPSRC UK National Service for 
Computational Chemistry Software (NSCCS) at Imperial College London in carrying out this work.This is the final version of the article. It first appeared from Wiley via http://dx.doi.org/10.1002/adfm.20150153
Fragile-to-Strong Crossover in Supercooled Liquid Ag-In-Sb-Te Studied by Ultrafast Calorimetry

Phase-change random-access memory relies on the reversible crystalline-glassy phase change in chalcogenide thin films. In this application, the speed of crystallization is critical for device performance: there is a need to combine ultrafast crystallization for switching at high temperature with high resistance to crystallization for non-volatile data retention near to room temperature. In phase-change media such as nucleation-dominated Ge2Sb2Te5, these conflicting requirements are met through the highly “fragile” nature of the temperature dependence of the viscosity of the supercooled liquid. The present study explores, using ultrafast-heating calorimetry, the equivalent temperature dependence for the growth-dominated medium Ag-In-Sb-Te. The crystallization shows (unexpectedly) Arrhenius temperature dependence over a wide intermediate temperature range. Here it is shown that this is evidence for a fragile-to-strong crossover on cooling the liquid. Such a crossover has many consequences for the interpretation and control of phase-change kinetics in chalcogenide media, helping to understand the distinction between nucleation- and growth-dominated crystallization, and offering a route to designing improved device performance.J.O., D.W.H. and A.L.G. acknowledge support from the Engineering and Physical Sciences Research Council (EPSRC, UK), D.W.H. in part through the EPSRC Centre for Innovative Manufacturing in Photonics. J.O. and A.L.G. acknowledge support from the World Premier International Research Center Initiative (WPI), MEXT, Japan. C. A. Angell, L. Battezzati, G. Dalla Fontana and M. Salinga are thanked for helpful discussions.This is the author accepted manuscript. The final version is available from Wiley at http://onlinelibrary.wiley.com/doi/10.1002/adfm.201501607/abstract
Design and Integration in Electro-Optic Devices of Highly Efficient and Robust Red-NIR Phosphorescent Nematic Hybrid Liquid Crystals Containing [Mo6I8(OCOCnF2n+1)6]2− (n = 1, 2, 3) Nanoclusters

International audienceBy combining [Mo6I8(C n F2n+1COO)6]2- (n = 1, 2, 3) nanocluster units with liquid crystalline ammonium cations, a new series of hybrid materials is developed that show a nematic liquid crystal phase, the most fluid of all LC phase, on a large range of temperatures including room temperature. The photophysical studies performed in the LC state show that these self-assembled hybrid materials emit in the red-NIR with absolute quantum yields up to 0.7 and show a very good photostability under continuous irradiation. They are further integrated up to 20 wt% in E7, a well-known nematic commercial LC mixture. Mixtures are investigated in terms of homogeneity and stability to select the best suitable candidate for the design of electro-controlled devices. Studies of optical switching, contrast, viscosity, and behavior toward an electrical stimulus demonstrate the high potential of these hybrid materials in the fields of photonic or optoelectronic
Vectorially Imprinted Hybrid Nanofilm for Acetylcholinesterase Recognition

Effective recognition of enzymatically active tetrameric acetylcholinesterase (AChE) is accomplished by a hybrid nanofilm composed of a propidium-terminated self-assembled monolayer (Prop-SAM) which binds AChE via its peripheral anionic site (PAS) and an ultrathin electrosynthesized molecularly imprinted polymer (MIP) cover layer of a novel carboxylate-modified derivative of 3,4-propylenedioxythiophene. The rebinding of the AChE to the MIP/Prop-SAM nanofilm covered electrode is detected by measuring in situ the enzymatic activity. The oxidative current of the released thiocholine is dependent on the AChE concentration from ≈0.04 × 10−6 to 0.4 × 10−6m. An imprinting factor of 9.9 is obtained for the hybrid MIP, which is among the best values reported for protein imprinting. The dissociation constant characterizing the strength of the MIP-AChE binding is 4.2 × 10−7m indicating the dominant role of the PAS-Prop-SAM interaction, while the benefit of the MIP nanofilm covering the Prop-SAM layer is the effective suppression of the cross-reactivity toward competing proteins as compared with the Prop-SAM. The threefold selectivity gain provided by i) the “shape-specific” MIP filter, ii) the propidium-SAM, iii) signal generation only by the AChE bound to the nanofilm shows promise for assessing AChE activity levels in cerebrospinal fluid