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An efficient method that utilizes simple techniques, easy operation, and low‐cost production to create flexible graphene‐based materials is a worthy practical challenge. A rapid strategy for preparing flexible, functional graphene oxide (GO) is introduced using GO‐ethanol dispersion filtration. The filtration process is highly efficient and drying time is significantly reduced by employing ethanol as solvent, due to the fact that ethanol is a volatile liquid. Freestanding GO papers can be harvested with ultralarge size (700 cm2), color variety, and writable characteristics. After reduction, N‐doped graphene (NDG) papers still maintain good foldability with improved electric conductivity and porous structure. When used as an electrode for a supercapacitor, the flexible NDG paper device demonstrates good electrochemical performance even with size expansion and extreme double folding. Moreover, this NDG paper capacitor device shows a good electrosorption performance for capacitive deionization of sulfate and chromate in groundwater system. These flexible GO and NDG papers promise potential to facilitate the production of graphene‐based materials for practical applications in energy and environmental related fields.

This work reports a modification of a fibrous cellulose material (paper) by the addition of polyacrylonitrile (PAN) fibres doped with 10,12–pentacosadiynoic acid (PDA). The fibres are sensitive to ultraviolet (UV) light. When the paper containing PAN–PDA is irradiated with UV light it changes colour to blue as a consequence of interaction of the light with PDA. The colour intensity is related to the absorbed dose, content of PAN–PDA fibres in the paper and the wavelength of UV radiation. The features of the paper are summarised after reflectance spectrophotometry and scanning microscopy analyses. All the properties of the modified paper were tested in accordance with adequate ISO standards. Moreover, a unique method for assessing the unevenness of the paper surface and the quality of printing was proposed by using a Python script (RGBreader) for the analysis of RGB colour channels. The modification applied to the paper can serve as a paper security system. The modified paper can act also as a UV radiation indicator.

Made available in DSpace on 2020-12-12T02:09:36Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-06-03 In this study, the direct analysis of doping agents in urine samples with no sample preparation by a modified paper spray mass spectrometry (PS-MS) methodology has been demonstrated for the first time. We have described a paper surface treatment with trichloromethylsilane using a gas-phase reaction to increase the ionization of target compounds. This approach was applied for the analysis of two classes of banned substances in urine samples: anabolic agents (trenbolone and clenbuterol) and diuretics (furosemide and hydrochlorothiazide). Under optimized conditions, the developed methods presented satisfactory repeatability, and an analysis of variance showed linearity without lack-of-fit. Highly sensitive detections as low as sub-nanogram per milliliter levels, which is below the minimum required performance levels proposed by the World Anti-Doping Agency, have been reached using the hydrophobic PS-MS analysis without any preconcentration and cleanup step. Department of Chemistry and Biochemistry Ohio State University, 100 West 18th Avenue Institute of Chemistry Department of Analytical Chemistry São Paulo State University (UNESP), Rua Professor Francisco Degni 55 ,P.O. Box 355 Institute of Chemistry Department of Analytical Chemistry São Paulo State University (UNESP), Rua Professor Francisco Degni 55 ,P.O. Box 355

A superior electrical conductivity of 38.5 S/cm and an electromagnetic shielding (EMS) effectiveness of −30 dB (−545 dB/mm) across a wide frequency range of 0–15 GHz, including the X-band, were achieved with thin organic paper of (55 μm) cellulose nanofiber (CNF)/polyaniline (PANI) doped with (±)-10-camphorsulfonic acid nanohybrid. Both electrical conductivity and EMS effectiveness of the PANI-coated CNF were strongly affected by the amount and type of dopant, which could be tunable after fabrication process via simple in situ oxidative polymerization of aniline. Flexible and free-standing film was obtained, since CNF provides good mechanical property without diminishing the electrical property of PANI.

Over the last decade, interest in the utilization of solar energy for photocatalysis treatment processes has taken centre-stage. Researchers had focused on doping TiO2 with SiO2 to obtain an efficient degradation rate of various types of target pollutants both under UV and visible-light irradiation. In order to further improve this degradation effect, some researchers resorted to incorporate plasmonic metal nanoparticles such as silver and gold into the combined TiO2-SiO2 to fully optimize the TiO2-SiO2’s potential in the visible-light region. This article focuses on the challenges in utilizing TiO2 in the visible-light region, the contribution of SiO2 in enhancing photocatalytic activities of the TiO2-SiO2 photocatalyst, and the ability of plasmonic metal nanoparticles (Ag and Au) to edge the TiO2-SiO2 photocatalyst toward an efficient solar photocatalyst.

In this study, we report poly(1H-thieno[3,4-d]imidazol-2(3H)-one) (pTIO) derivatives for an electrochromic (EC) type e-paper and its novel printing fabrication process. pTIO is a kind of conductive polymer (CP) s which are known as one of the EC materials. The electrochromism of pTIO is unique, because its color in doped state is almost transparent (pale gray). A transparent state is required to show a white color in a see-through view of an EC type e-paper. An electrochromism of CP has a good memory effect which is applicable for e-paper. The corresponding monomers of CP are able to be polymerized with an electrochemical method, which be made good use of for the fabrication process of e-paper. pTIO derivatives are copolymerized with other pi-conjugated X unit, which adjusts the color of electrochromism. Finally, we fabricated a segment matrix EC display using pTIO derivatives by ink-jet printing.

The electrical properties of RF-sputtered Al-doped ZnO are often spatially inhomogeneous and strongly dependent on deposition parameters. In this work, we study the mechanisms that limit the minimum resistivity achievable under different deposition regimes. In a low- and intermediate-pressure regime, we find a generalized dependence of the electrical properties, grain size, texture, and Al content on compressive stress, regardless of sputtering pressure or position on the substrate. In a high-pressure regime, a porous microstructure limits the achievable resistivity and causes it to increase over time as well. The primary cause of inhomogeneity in the electrical properties is identified as energetic particle bombardment. Inhomogeneity in oxygen content is also observed, but its effect on the electrical properties is small and limited to the carrier mobility.

The effect of silica nanoparticle (Nano-SiO2) dopants on insulation paper cellulose, and the interaction between them, was investigated using molecular dynamics simulations. The mechanical properties, interactions, and cellulose-Nano-SiO2 compatibility of composite models of cellulose doped with Nano-SiO2 were studied. An increase in Nano-SiO2 size leads to a decrease in the mechanical properties, and a decrease in the anti-deformation ability of the composite model. The binding energies and bond energies per surface area of the composite models indicate that the bonding interaction between spherical Nano-SiO2 and cellulose is the strongest among the four different Nano-SiO2 shapes that are investigated. The solubilities of the four composite models decrease with increasing Nano-SiO2 size, and the difference between the solubility of pure cellulose and those of the composite models increases with increasing Nano-SiO2 size. Good doping effects with the highest cellulose-Nano-SiO2 compatibility are achieved for the cellulose model doped with spherical Nano-SiO2 of 10 A in diameter. These findings provide a method for modifying the mechanical properties of cellulose by doping, perhaps for improving insulation dielectrics.

Single transition metal (TM) atoms such as Fe, Co and Ni occupying a carbon divacancy in tetragonal graphene (TG) and bonded with four nitrogen atoms (TM@N4TG) as electrocatalysts are investigated by means of first‐principles calculations. To consider the effect of solvent species on the local configuration of the active single metal, a thermodynamical full‐landscape searching (TFLS) scheme is employed. The calculated thermodynamic overpotentials (ηtd) from our TFLS indicate that Co@N4TG displays high catalytic activity toward both oxygen evolution reaction (OER) and reduction reaction (ORR), with ηtd OER and ηtd ORR as 0.397 and 0.357 V, respectively. Its OER potential cannot be captured if only one four electron reaction loop (FERL) is considered. The actual active pathways do not always turn out to be the reactions starting from the bare site. Our findings demonstrate that TG is a promising support and TM confined TD can be used to design effective and cheap multifunctional electrocatalysts., Doped Tetragonal Graphene (TG) as electrocatalyst? The pre‐adsorption of solvent functional groups (OH, O and OOH) can tune the adsorption strength of species. A thermodynamic full‐landscape searching scheme is proposed where all the possible reactions were considered. Co@N4TG is confirmed to be a favorable bifunctional single‐atom electrocatalyst for both OER and ORR.

TFET based label-free biosensors are fast, sensitive and more power efficient as compared to CMOS biosensors, which are prone to short channel effects (SCEs). However, literature is flooded with various TFET biosensors that have become the reason of dilemma for researchers during pandemic situations like COVID-19. Therefore, in this work, a physically doped (PD), charge plasma (CP) and electrically doped (ED) dielectric modulated (DM) TFET based label-free biosensors are compared, which cover almost the entire range of doping and junctionless devices. Also, we found that the ED based TFET biosensors provide better current sensitivities of 5.10 x 10(7), 4.77 x 10(8) and 7.11 x 10(8) for biomolecules with K=12, positive charge= 1 x 10(13) C/cm(2) and negative charge= -1 x 10(13) C/cm(2) respectively. Hence, ED-DM-TFET based biosensors can act as promising candidates to provide better detection and identification quality.

Atomic dispersion of dopants and control over their defect chemistry are central goals in the development of oxide nanoparticles for functional materials with dedicated electronic, optical or magnetic properties. We produced highly dispersed oxide nanocubes with atomic distribution of cobalt ions in substitutional sites of the MgO host lattice via metal organic chemical vapor synthesis. Vacuum annealing of the nanoparticle powders up to 1173 K has no effect on the shape of the individual particles and only leads to moderate particle coarsening. Such materials processing, however, gives rise to the electronic reduction of particle surfaces, which—upon O2 admission—stabilize anionic oxygen radicals that are accessible to UV/Vis diffuse reflectance and electron paramagnetic resonance (EPR) spectroscopy. Multi‐reference quantum chemical calculations show that the optical bands observed mainly originate from transitions into 4A2g (4F), 4T1g (4P) states with a contribution of transitions into 2T1g, 2T2g (2G) states through spin‐orbit coupling and gain intensity through vibrational motion of the MgO lattice or the asymmetric ion field. Related nanostructures are a promising material system for single atomic site catalysis. At the same time, it represents an extremely valuable model system for the study of interfacial electron transfer processes that are key to nanoparticle chemistry and photochemistry at room temperature, and in heterogeneous catalysis., A MgO host lattice with an atomic distribution of cobalt ions in substitutional sites was achieved via metal organic chemical vapor synthesis, providing a promising material system for single atomic site catalysis and a good model system for the study of interfacial electron transfer processes that are key to nanoparticle chemistry and photochemistry at room temperature, and in heterogeneous catalysis.

To promote the interaction of p–n semiconductors, raspberry‐like microspheres of core–shell Cr2O3@TiO2 nanoparticles have been fabricated through a five‐step process. Raman spectroscopy of products calcined at various temperatures reveal that the titania shell causes crystal distortion of the Cr2O3 core, without changing the microstructures of the fabricated core–shell microspheres. In situ and time‐resolved synchrotron‐based powder XRD reveals the formation of monoclinic TiO2 in the fourth step, but these monoclinic TiO2 nanocrystals undergo a phase transition when the applied calcination temperature is above 550 °C. As a result, TiO2(B), a magnéli phase of Ti4O7 and Cr2Ti6O15 compounds, resulting from inner doping between Cr2O3 and TiO2, is formed. The close interaction of Cr2O3 and TiO2 forms a p–n junction that decreases the recombination of photogenerated electron–hole pairs, leading to enhanced production of CH4 by photocatalytic reduction of CO2., Giving CO2 conversion the raspberry: To promote the interaction of p–n semiconductors, raspberry‐like core–shell Cr2O3@TiO2 nanoparticles were fabricated through a five‐step process. The products calcined at different temperatures revealed that the titania shell resulted in the crystal distortion of the Cr2O3 core, without changing the microstructures of the fabricated core–shell microspheres.

In the current study, by employing first-principles computations, the adsorption behavior of letrozole (LET) was investigated on the pristine graphdiyne nanosheet (GDY) as well as Si-doped graphdiyne (SiGDY). According to the adsorption energy, charge transfer value, and the change in the bang gap energy, the tendency of the pristine GDY towards LET is insignificant. However, the interaction of LET with SiGDY was strong and the adsorption energy was approximately − 19.20 kcal/mol. In addition, the associated electrical conductivity with SiGDY increased by approximately 23.53 % following the adsorption of LET. The results show that SiGDY can be employed as an electronic sensor to detect LET. Furthermore, LET is detected by SiGDY in the water phase based on the magnitude of solvation energy. Finally, a considerable charge-transfer between LET and SiGDY is a precondition for the adsorption of the LET molecule with proper binding energies, which delivers the Si atoms with a significant positive charge.

Thermoelectric generators made by large arrays of nanowires perpendicular to a silicon substrate, that is, so-called silicon nanowire forests are fabricated on large areas by an inexpensive metal-assisted etching technique. After fabrication, a thermal diffusion process is used for doping the nanowire forest with phosphorous. A suitable experimental technique has been developed for the measurement of the Seebeck coefficient under static conditions, and results are reported for different doping parameters. These results are in good agreement with numerical simulations of the doping process applied to silicon nanowires. These devices, based on doped nanowire forests, offer a possible route for the exploitation of the high power factor of silicon, which, combined with the very low thermal conductivity of nanostructures, will yield a high efficiency of the conversion of thermal to electrical energy.

Transition metal dichalcogenides (TMDCs) have received attention as atomically thin post‐silicon semiconducting materials. Tuning the carrier concentrations of the TMDCs is important, but their thin structure requires a non‐destructive modulation method. Recently, a surface‐charge transfer doping method was developed based on contacting molecules on TMDCs, and the method succeeded in achieving a large modulation of the electronic structures. The successful dopant is a neutral benzyl viologen (BV0); however, the problem remains of how to effectively prepare the BV0 molecules. A reduction process with NaBH4 in water has been proposed as a preparation method, but the NaBH4 simultaneously reacts vigorously with the water. Here, a simple method is developed, in which the reaction vial is placed on a hotplate and a fragment of air‐stable metal is used instead of NaBH4 to prepare the BV0 dopant molecules. The prepared BV0 molecules show a strong doping ability in terms of achieving a degenerate situation of a TMDC, MoS2. A key finding in this preparation method is that a convection flow in the vial effectively transports the produced BV0 to a collection solvent. This method is simple and safe and facilitates the tuning of the optoelectronic properties of nanomaterials by the easily‐handled dopant molecules.

Manganese‐zinc ferrite nanoparticles were synthesized by using a hydrothermal treatment, coated with silica, and then tested as efficient cellular labels for cell tracking, using magnetic resonance imaging (MRI) in vivo. A toxicity study was performed on rat mesenchymal stem cells and C6 glioblastoma cells. Adverse effects on viability and cell proliferation were observed at the highest concentration (0.55 mM) only; cell viability was not compromised at lower concentrations. Nanoparticle internalization was confirmed by transmission electron microscopy. The particles were found in membranous vesicles inside the cytoplasm. Although the metal content (0.42 pg Fe/cell) was lower compared to commercially available iron oxide nanoparticles, labeled cells reached a comparable relaxation rate R 2, owing to higher nanoparticle relaxivity. Cells from transgenic luciferase‐positive rats were used for in vivo experiments. Labeled cells were transplanted into the muscles of non‐bioluminescent rats and visualized by MRI. The cells produced a distinct hypointense signal in T2‐ or T2*‐weighted MR images in vivo. Cell viability in vivo was verified by bioluminescence.

The development of ultrastable carbon materials for potassium storage poses key limitations caused by the huge volume variation and sluggish kinetics. Nitrogen‐enriched porous carbons have recently emerged as promising candidates for this application; however, rational control over nitrogen doping is needed to further suppress the long‐term capacity fading. Here we propose a strategy based on pyrolysis–etching of a pyridine‐coordinated polymer for deliberate manipulation of edge‐nitrogen doping and specific spatial distribution in amorphous high‐surface‐area carbons; the obtained material shows an edge‐nitrogen content of up to 9.34 at %, richer N distribution inside the material, and high surface area of 616 m2 g−1 under a cost‐effective low‐temperature carbonization. The optimized carbon delivers unprecedented K‐storage stability over 6000 cycles with negligible capacity decay (252 mA h g−1 after 4 months at 1 A g−1), rarely reported for potassium storage., Pyrolysis–etching of a pyridine‐coordinated polymer was used to prepare a porous carbon material with defect edge‐enriched N‐6/N‐5 doping, high surface area, and rich distribution of N defects within the material. This carbonaceous material allows full utilization of surface‐dominated capacitive K storage with ultrastable cycling.

The added value of dried blood spot (DBS) samples complementing the information obtained from commonly routine doping control matrices is continuously increasing in sports drug testing. In this project, a robotic-assisted non-destructive hematocrit measurement from dried blood spots by near-infrared spectroscopy followed by a fully automated sample preparation including strong cation exchange solid-phase extraction and evaporation enabled the detection of 46 lower molecular mass (

Amorphous and graphitized nitrogen-doped (N-doped) carbon spheres are investigated as structurally well-defined model systems to gain a deeper understanding of the relationship between synthesis, structure, and their activity in the oxygen reduction reaction (ORR). N-doped carbon spheres were synthesized by hydrothermal treatment of a glucose solution yielding carbon spheres with sizes of 330 ± 50 nm, followed by nitrogen doping via heat treatment in ammonia atmosphere. The influence of a) varying the nitrogen doping temperature (550–1000 °C) and b) of a catalytic graphitization prior to nitrogen doping on the carbon sphere morphology, structure, elemental composition, N bonding configuration as well as porosity is investigated in detail. For the N-doped carbon spheres, the maximum nitrogen content was found at a doping temperature of 700 °C, with a decrease of the N content for higher temperatures. The overall nitrogen content of the graphitized N-doped carbon spheres is lower than that of the amorphous carbon spheres, however, also the microporosity decreases strongly with graphitization. Comparison with the electrocatalytic behavior in the ORR shows that in addition to the N-doping, the microporosity of the materials is critical for an efficient ORR.

At the organic–inorganic interface of nanocrystals, electron‐phonon coupling plays an important but intricate role in determining the diverse properties of nanomaterials. Here, it is reported that highly doping of Yb3+ ions within the nanocrystal host can form an energy‐migration network. The networking state Yb3+ shows both distinct Stark splitting peak ratios and lifetime dynamics, which allows quantitative investigations of quenching and thermal activation of luminescence, as the high‐dimensional spectroscopy signatures can be correlated to the attaching and de‐attaching status of surface molecules. By in‐situ surface characterizations, it is proved that the Yb‐O coordination associated with coordinated water molecules has significantly contributed to this reversible effect. Moreover, using this approach, the prime quencher —OH can be switched to —CH in the wet‐chemistry annealing process, resulting in the electron‐phonon coupling probability change. This study provides the molecular level insights and dynamics of the surface dark layer of luminescent nanocrystals., Doping Yb3+ ions in nanocrystals, particularly at high concentrations, enables the Yb3+ ions to constitute energy transfer network and display many distinct dynamic features, including the temperature‐responsive Yb3+ lifetimes and Stark splitting spectra. This allows us to achieve the molecular‐level understanding of the organic–inorganic interface interactions and their relations to the luminescence behaviors.

Inorganic perovskite solar cells (PSCs) have witnessed great progress in recent years due to their superior thermal stability. As a representative, CsPbI2Br is attracting considerable attention as it can balance the high efficiency of CsPbI3 and the stability of CsPbBr3. However, most research employs doped charge transport materials or applies bilayer transport layers to obtain decent performance, which vastly complicates the fabrication process and scarcely satisfies the commercial production requirement. In this work, all‐layer‐doping‐free inorganic CsPbI2Br PSCs using organic ligands armored ZnO as the electron transport materials achieve an encouraging performance of 16.84%, which is one of the highest efficiencies among published works. Meanwhile, both the ZnO‐based CsPbI2Br film and device show superior photostability under continuous white light‐emitting diode illumination and improved thermal stability under 85 °C. The remarkable enhanced performance arises from the favorable organic ligands (acetate ions) residue in the ZnO film, which not only can conduce to maintain high crystallinity of perovskite, but also passivate traps at the interface through cesium/acetate interactions, thus suppressing the photo‐ and thermal‐ induced perovskite degradation., An inorganic CsPbI2Br perovskite solar cell employing organic ligands armored ZnO as the electron transport materials achieves a maximum power conversion efficiency of 16.84%, with superior photo‐ and thermal‐ stabilities.

Optical thermal sensing holds great promise for disease theranostics. However, traditional ratiometric thermometry methods, in which intensity ratio of two nonoverlapping emissions is defined as the thermosensitive parameter, may have a limited accuracy in temperature read‐out due to the deleterious interference from wavelength‐ and temperature‐dependent photon attenuation in tissue. To overcome this limitation, a dual‐excitation decoding strategy based on NIR hybrid nanocomposites comprising self‐assembled quantum dots (QDs) and Nd3+ doped fluoride nanocrystals (NCs) is proposed for thermal sensing. Upon excitation at 808 nm, the intensity ratio of two emissions at identical wavelength (1057 nm) from QDs and NCs, respectively, is defined as the thermometric parameter R. By employing another 830 nm laser beam following the same optical path as 808 nm laser to exclusively excite QDs, the two overlapping emissions can be easily decoded. The acquired R proves to be inert to the detection depth in tissue, with a minimized temperature reading error of ≈2.3 °C at 35 °C (at a depth of ≈1.1 mm), while the traditional thermometry mode based on the nonoverlapping 1025 and 863 nm emissions may exhibit a large error of ≈43.0 °C. The insights provided by this work pave the way toward high‐accuracy deep‐tissue biosensing., A dual‐excitation decoding strategy, which uses the intensity ratio of two overlapping NIR emissions from self‐assembled QDs and Nd3+ doped fluoride NCs in the hybrid nanocomposites, respectively, as the ratiometric thermometric parameter, is proposed for high‐accuracy thermal sensing in vivo.

Trivalent lanthanide (Ln3+)‐doped hollow upconversion nanocrystals (UCNCs) usually exhibit unique optical performance that cannot be realized in their solid counterparts, and thus have been receiving tremendous interest from their fundamentals to diverse applications. However, all currently available Ln3+‐doped UCNCs are solid in appearance, the preparation of hollow UCNCs remains nearly untouched hitherto. Herein, a class of UCNCs based on Yb3+/Er3+‐doped tetralithium zirconium octafluoride (Li4ZrF8:Yb/Er) featuring 2D layered crystal lattice is reported, which makes the fabrication of hollow UCNCs with a peasecod‐like shape possible after Ln3+ doping. By employing the first‐principle calculations, the unique peasecod‐like hollow nanoarchitecture primarily associated with the hetero‐valence Yb3+/Er3+ doping into the 2D layered crystal lattice of Li4ZrF8 matrix is revealed. Benefiting from this hollow nanoarchitecture, the resulting Li4ZrF8:Yb/Er UCNCs exhibit an abnormal green upconversion luminescence in terms of the population ratio between two thermally coupled states (2H11/2 and 4S3/2) of Er3+ relative to their solid Li2ZrF6:Yb/Er counterparts, thereby allowing to prepare the first family of hollow Ln3+‐doped UCNCs as supersensitive luminescent nanothermometer with almost the widest temperature sensing range (123–800 K). These findings described here unambiguously pave a new way to fabricate hollow Ln3+‐doped UCNCs for numerous applications., A class of peasecod‐like hollow Yb3+/Er3+‐doped Li4ZrF8 upconverting nanocrystals (UCNCs) that features a 2D layered crystal lattice is reported. Abnormal green upconverting luminescence that cannot be achieved in the solid UCNCs is observed in these peasecod‐like hollow UCNCs, thereby making them suitable as supersensitive nanothermometers with a wide temperature range for optical temperature sensing.

Controlling the growth behavior of organic semiconductors (OSCs) is essential because it determines their optoelectronic properties. In order to accomplish this, graphene templates with electronic‐state tunability are used to affect the growth of OSCs by controlling the van der Waals interaction between OSC ad‐molecules and graphene. However, in many graphene‐molecule systems, the charge transfer between an ad‐molecule and a graphene template causes another important interaction. This charge‐transfer‐induced interaction is never considered in the growth scheme of OSCs. Here, the effects of charge transfer on the formation of graphene–OSC heterostructures are investigated, using fullerene (C60) as a model compound. By in situ electrical doping of a graphene template to suppress the charge transfer between C60 ad‐molecules and graphene, the layer‐by‐layer growth of a C60 film on graphene can be achieved. Under this condition, the graphene–C60 interface is free of Fermi‐level pinning; thus, barristors fabricated on the graphene–C60 interface show a nearly ideal Schottky–Mott limit with efficient modulation of the charge‐injection barrier. Moreover, the optimized C60 film exhibits a high field‐effect electron mobility of 2.5 cm2 V−1 s−1. These results provide an efficient route to engineering highly efficient optoelectronic graphene–OSC hybrid material applications., The growth behavior of fullerene (C60) thin films on graphene templates where charge transfer occurs is presented. The number of electrons transferred from graphene to C60 is controlled by in situ electrical gating of graphene during C60 deposition. When this electron transfer is suppressed, high‐crystalline C60 thin films are achieved for highly efficient optoelectronic applications.

Hybridizing graphene and molecules possess a high potential for developing materials for new applications. However, new methods to characterize such hybrids must be developed. Herein, the wet‐chemical non‐covalent functionalization of graphene with cationic π‐systems is presented and the interaction between graphene and the molecules is characterized in detail. A series of tricationic benzimidazolium salts with various steric demand and counterions was synthesized, characterized and used for the fabrication of graphene hybrids. Subsequently, the doping effects were studied. The molecules are adsorbed onto graphene and studied by Raman spectroscopy, XPS as well as ToF‐SIMS. The charged π‐systems show a p‐doping effect on the underlying graphene. Consequently, the tricationic molecules are reduced through a partial electron transfer process from graphene, a process which is accompanied by the loss of counterions. DFT calculations support this hypothesis and the strong p‐doping could be confirmed in fabricated monolayer graphene/hybrid FET devices. The results are the basis to develop sensor applications, which are based on analyte/molecule interactions and effects on doping., Organic star‐shaped tricationic molecules interact with graphene and a one‐electron transfer from graphene to the molecules leads to strong p‐doping.

ChemSusChem 13(12), 3243 - 3251 (2020). doi:10.1002/cssc.202000407, The direct synthesis of H$_2$O$_2$ from H$_2$ and O$_2$ is a strongly desired reaction for green processes and a promising alternative to the commercialized anthraquinone process. The design of efficient catalysts with high activity and H$_2$O$_2$ selectivity is highly desirable and yet challenging. Metal dopants enhance the performance of the active phase by increasing reaction rates, stability, and/or selectivity. The identification of efficient dopants relies mostly on catalysts prepared with a random and non-uniform deposition of active and promoter phases. To study the promotional effects of metal doping on Pd catalysts, we employ colloidal, bimetallic nanocrystals (NCs) to produce catalysts in which the active and doping metals are colocalized to a fine extent. In the absence of any acid and halide promotors, PdSn and PdGa NCs supported on acid-pretreated TiO$_2$ (PdSn/s-TiO$_2$, PdGa/s-TiO$_2$) were highly efficient and outperformed the monometallic Pd catalyst (Pd/s-TiO$_2$), whereas in the presence of an acid promotor, the overall H$_2$O$_2$ productivity was also further enhanced for the Ni-, Ga-, In-, and Sn-doped catalysts with respect to Pd/s-TiO$_2$., Published by Wiley-VCH, Weinheim

Ceria particles play a key role in catalytic applications such as automotive three‐way catalytic systems in which toxic CO and NO are oxidized and reduced to safe CO2 and N2, respectively. In this work, we explore the incorporation of Cu and Cr metals as dopants in the crystal structure of ceria nanorods prepared by a single‐step hydrothermal synthesis. XRD, Raman and XPS confirm the incorporation of Cu and Cr in the ceria crystal lattices, offering ceria nanorods with a higher concentration of oxygen vacancies. XPS also confirms the presence of Cr and Cu surface species. H2‐TPR and XPS analysis show that the simultaneous Cu and Cr co‐doping results in a catalyst with a higher surface Cu concentration and a much‐enhanced surface reducibility, in comparison with either undoped or singly doped (Cu or Cr) ceria nanorods. While single Cu doping enhances catalytic CO oxidation and Cr doping improves catalytic NO reduction, co‐doping with both Cu and Cr enhances the benefits of both dopants in a synergistic manner employing roughly a quarter of dopant weight., Doped up for detox: Ceria particles play a key role in catalytic applications such as automotive three‐way catalytic systems in which toxic CO and NO are respectively oxidized and reduced to safe CO2 and N2. We explored the incorporation of Cu and Cr metals as dopants in the crystal structure of ceria nanorods prepared by a single‐step hydrothermal synthesis. Such co‐doped ceria nanorods show synergistic improvement in reducibility and enhanced performance for CO oxidation and NO reduction.

This paper details the application of phosphorus monolayer doping of silicon on insulator substrates. There have been no previous publications dedicated to the topic of MLD on SOI, which allows for the impact of reduced substrate dimensions to be probed. The doping was done through functionalization of the substrates with chemically bound allyldiphenylphosphine dopant molecules. Following functionalization, the samples were capped and annealed to enable the diffusion of dopant atoms into the substrate and their activation. Electrical and material characterisation was carried out to determine the impact of MLD on surface quality and activation results produced by the process. MLD has proven to be highly applicable to SOI substrates producing doping levels in excess of 1 × 1019 cm−3 with minimal impact on surface quality. Hall effect data proved that reducing SOI dimensions from 66 to 13 nm lead to an increase in carrier concentration values due to the reduced volume available to the dopant for diffusion. Dopant trapping was found at both Si–SiO2 interfaces and will be problematic when attempting to reach doping levels achieved by rival techniques.

Liquid‐like materials are one family of promising thermoelectric materials discovered in the past years due to their advantanges of ultrahigh thermoelectric figure of merit (zT), low cost, and environmental friendliness. However, their practial applications are greatly limited by the low service stability from the Cu/Ag metal deposition under large current and/or temperature gradient. Both high zT for high efficiency and large critical voltage for good stability are required for liquid‐like materials, but they are usually strongly correlated and hard to be tuned individually. Herein, based on the thermodynamic analysis, it is shown that such a correlation can be decoupled through doping immobile ions into the liquid‐like sublattice. Taking Cu2− δS as an example, doping immobile Fe ions in Cu1.90S scarcely degrades the initial large critical voltage, but significantly enhances the zT to 1.5 at 1000 K by tuning the carrier concentration to the optimal range. Combining the low‐cost and environmentally friendly features, these Fe‐doped Cu2− δS‐based compounds show great potential in civil applications. This study sheds light on the realization of both good stability and high performance for many other liquid‐like thermoelectric materials that have not been considered for real applications before., Herein, the correlation between thermoelectric figure of merit and critical voltage is revealed and the thermodynamic analysis suggests that it can be decoupled through doping immobile ions into the liquid‐like sublattice. Along this direction, a new approach to design and fabricate liquid‐like materials with both high thermoelectric performance and good stability is proposed and well demonstrated in Cu2− δS‐based liquid‐like materials.

We study the allylic oxidation of cyclohexene with dioxygen under mild conditions in the presence of transition-metal catalysts. The catalysts are comprised of nanometric metal oxide particles supported on porous nitrogen-doped carbons (M/N:C, where M = V, Cr, Fe, Co, Ni, Cu, Nb, Mo, and W). Most of these metal oxides give only moderate conversions, whereof the majority of the products are over-oxidation products. Co/N:C and Cu/N:C, however, give 70-80% conversion and 40-50% selectivity to the ketone product, cyclohexene-2-one. Control experiments using free-radical scanvengers shows that the oxidation follows the expected free-radical pathway in almost all cases. Surprisingly, the catalytic cycle in the presence of Cu/N:C does not involve free-radical species in solution. Optimisation of this catalyst gives >85% conversion with >60% selectivity to the allylic ketone, at 70 °C and 10 bar oxygen pressure. Scanning electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction studies show that the active particles have a cupric oxide/cuprous oxide core/shell structure, with a correspondingly high TOF of ca. 1500 h-1. We attribute the high performance of this Cu/N:C catalyst to a facile surface reaction between adsorbed cyclohexenyl hydroperoxide molecules and activated oxygen species.

PubMed: 31293857, Phosphors can serve as color conversion layers to generate white light with varying optical features, including color rendering index (CRI), high correlated color temperature (CCT), and luminous efficacy. However, they are typically produced under harsh synthesis conditions such as high temperature, high pressure, and/or by employing a large amount of solvent. In this work, a facile, water-based, rapid method has been proposed to fabricate lanthanide-doped hydroxide-based phosphors. In this sense, sub-micrometer-sized Y(OH)(3):Eu3+ particles (as red phosphor) were synthesized in water at ambient conditions in