Graphene on quartz modified with rhenium oxide as a semitransparent electrode for organic electronic

Our research shows that commercially available graphene on quartz modified with rhenium oxide meets the requirements for its use as a conductive and transparent anode in optoelectronic devices. The cluster growth of rhenium oxide enables an increase in the work function of graphene by 1.3 eV up to 5.2 eV, which guarantees an appropriate adjustment to the energy levels of the organic semiconductors used in OLED devices.Comment: 8 pages, 3 figure

Graphene and Beyond: Recent Advances in Two-Dimensional Materials Synthesis, Properties, and Devices

Since the isolation of graphene in 2004, two-dimensional (2D) materials research has rapidly evolved into an entire subdiscipline in the physical sciences with a wide range of emergent applications. The unique 2D structure offers an open canvas to tailor and functionalize 2D materials through layer number, defects, morphology, moir\ue9 pattern, strain, and other control knobs. Through this review, we aim to highlight the most recent discoveries in the following topics: theory-guided synthesis for enhanced control of 2D morphologies, quality, yield, as well as insights toward novel 2D materials; defect engineering to control and understand the role of various defects, including in situ and ex situ methods; and properties and applications that are related to moir\ue9 engineering, strain engineering, and artificial intelligence. Finally, we also provide our perspective on the challenges and opportunities in this fascinating field

Validation of selected molecular methods for the mutations determination in codons 12 and 13 of K-RAS gene in five Polish oncological research centers

Chorzy na raka jelita grubego z przerzutami mogą osiągnąć korzyść z leczenia panitumumabem jedynie, jeśli w guzie nie stwierdzono mutacji w genie K-RAS. W związku z tym konieczne jest zbadanie statusu tego genu w celu wyłonienia chorych, którzy mogą być poddani takiemu leczeniu. Celem pracy było opracowanie standardowej procedury oznaczania statusu genu K-RAS w materiale izolowanym z bloczków parafinowych. Kolejnym celem była walidacja wybranych technik molekularnych oznaczania mutacji w pięciu ośrodkach w Polsce, w których odbywa się leczenie chorych na raka jelita grubego. Ocenie poddano cztery różne techniki oznaczania mutacji: SSCP, DHPLC, RFLP/PCR i bezpośrednie sekwencjonowanie. Stwierdzono, że wszystkie jednostki uczestniczące w procesie walidacji są odpowiednio przygotowane do podjęcia działalności diagnostycznej w zakresie oznaczania statusu genu K-RAS. Przyjęto następujące zalecenia dla laboratoriów diagnostycznych: 1. Materiał do izolacji DNA powinien zawierać przynajmniej 70% utkania nowotworowego; 2. Ujednolicenie procedury izolacji DNA ze skrawków parafinowych wymaga stosowania gotowego zestawu do izolacji DNA; 3. W przypadku braku jednoznacznego wyniku konieczne jest stosowanie dwóch metod oznaczania mutacji, przy czym jedną z nich powinno być sekwencjonowanie bezpośrednie.Metastatic colorectal cancer patients will benefit from treatment with panitumumab only when they don't have mutation in K-RAS gene. Therefore, estimation of mutational status of K-RAS is necessary for the selection of patients, who should be treated with panitumumab. The aim of this study was to evolve a standard method of estimation of K-RAS mutational status in the material isolated from paraffin blocs. The second aim was the validation of selected molecular methods of K-RAS mutation evaluation in five Polish oncological centers where mCRC patients are treated. Four methods were evaluated: SSCP, DHPLC, RFLP/PCR and direct sequencing. We found that all groups in five selected oncological centers, who took part in the validation process, were well prepared for molecular diagnosis of K-RAS mutational status. The following recommendations for diagnostic laboratories were approved: 1. At least 70% of cancer cells should be present in a tissue for DNA isolation; 2. The method of DNA isolation should be standardized, the most appropriate is usage of DNA isolation kits; 3. In case of equivocal results two independent molecular methods should be employed, one of them should be direct sequencing

The effects of sex, age, season and habitat on diet of the red fox Vulpes vulpes in northeastern Poland

The diet of the red fox Vulpes vulpes was investigated in five regions of northeastern Poland by stomach content analysis of 224 foxes collected from hunters. The red fox is expected to show the opportunistic feeding habits. Our study showed that foxes preyed mainly on wild prey, with strong domination of Microtus rodents, regardless of sex, age, month and habitat. Voles Microtus spp. were found in 73% of stomachs and constituted 47% of food volume consumed. Other food items were ungulate carrion (27% of volume), other mammals (11%), birds (9%), and plant material (4%). Sex- and age-specific differences in dietary diversity were found. Adult males and juvenile foxes had larger food niche breadths than adult females and their diets highly overlapped. Proportion of Microtus voles increased from autumn to late winter. Significant habitat differences between studied regions were found. There was a tendency among foxes to decrease consumption of voles with increasing percentage of forest cover. Based on our findings, red foxes in northeastern Poland can be recognized as a generalist predators, consuming easily accessible and abundant prey. However, high percentage of voles consumed regardless of age, sex, month, or habitats may indicate red fox specialization in preying on Microtus rodents

Local electronic structure of stable monolayers of alpha-MoO3-x grown on graphite substrate

We report on van der Waals epitaxy of two-dimensional (2D) molybdenum trioxide (MoO3−x) with monolayer thickness directly grown on highly oriented pyrolytic graphite by thermal evaporation under ultrahigh vacuum. The chemical composition, electronic and crystalline lattice structures of the mono-and few-layer MoO3−x sheets are analysed. Using scanning tunnelling microscopy and spectroscopy, we investigate the electronic properties of MoO3−x as a function of the number of layers and measure the apparent energy gap to be 0.4 eV for the first three layers of MoO3−x on graphite. We carried out density functional theory calculations to shed light on the mechanism underlying the observed narrow bandgap with oxygen deficiency. Moreover, the air exposure effect on monolayer MoO3−x is investigated confirming that the apparent bandgap closes, and additionally we show the reduction of the work function from 5.7 to 4.7 eV. We prove that it is possible to synthesize the 2D, non-stoichiometric, and electrically conductive MoO3−x

Two-Dimensional Crystals as a Buffer Layer for High Work Function Applications: The Case of Monolayer MoO3

We propose that the crystallinity of two-dimensional (2D) materials is a crucial factor for achieving highly effective work function (WF) modification. A crystalline 2D MoO3 monolayer enhances substrate WF up to 6.4 eV for thicknesses as low as 0.7 nm. Such a high WF makes 2D MoO3 a great candidate for tuning properties of anode materials and for the future design of organic electronic devices, where accurate evaluation of the WF is crucial. We provide a detailed investigation of WF of 2D α-MoO3 directly grown on highly ordered pyrolytic graphite, by means of Kelvin probe force microscopy (KPFM) and ultraviolet photoemission spectroscopy (UPS). This study underlines the importance of a controlled environment and the resulting crystallinity to achieve high WF in MoO3. UPS is proved to be suitable for determining higher WF attributed to 2D islands on a substrate with lower WF, yet only in particular cases of sufficient coverage. KPFM remains a method of choice for nanoscale investigations, especially when conducted under ultrahigh vacuum conditions. Our experimental results are supported by density functional theory calculations of electrostatic potential, which indicate that oxygen vacancies result in anisotropy of WF at the sides of the MoO3 monolayer. These novel insights into the electronic properties of 2D-MoO3 are promising for the design of electronic devices with high WF monolayer films, preserving the transparency and flexibility of the systems

Electrostimulation and Nanomanipulation of Two-Dimensional MoO_3-x Layers Grown on Graphite

Molybdenum trioxide shows many attractive properties, such as a wide electronic band gap and a high relative permittivity. Monolayers of this material are particularly important, as they offer new avenues in optoelectronic devices, e.g., to alter the properties of graphene electrodes. Nanoscale electrical characterization is essential for potential applications of monolayer molybdenum trioxide. We present a conductive atomic force microscopy study of an epitaxially grown 2D molybdenum oxide layer on a graphene-like substrate, such as highly oriented pyrolytic graphite (HOPG). Monolayers were also investigated using X-ray photoelectron spectroscopy, atomic force microscopy (semi-contact and contact mode), Kelvin probe force microscopy, and lateral force microscopy. We demonstrate mobility of the unpinned island under slight mechanical stress as well as shaping and detachment of the material with applied electrical stimulation. Non-stoichiometric MoO3-x monolayers show heterogeneous behavior in terms of electrical conductivity, which can be related to the crystalline domains and defects in the structure. Different regions show various I–V characteristics, which are correlated with their susceptibility to electrodegradation. In this work, we cover the existing gap regarding nanomanipulation and electrical nanocharacterization of the MoO3 monolayer