42 research outputs found
Molecularly engineered black phosphorus heterostructures with improved ambient stability and enhanced charge carrier mobility
Overcoming the intrinsic instability and preserving unique electronic properties are key challenges for the practical applications of black phosphorus (BP) under ambient conditions. Here, it is demonstrated that molecular heterostructures of BP and hexaazatriphenylene derivatives (BP/HATs) enable improved environmental stability and charge transport properties. The strong interfacial coupling and charge transfer between the HATs and the BP lattice decrease the surface electron density and protect BP sheets from oxidation, resulting in an excellent ambient lifetime of up to 21 d. Importantly, HATs increase the charge scattering time of BP, contributing to an improved carrier mobility of 97 cm2 V-1 s-1, almost three times of the pristine BP films, based on noninvasive THz spectroscopic studies. The film mobility is an order of magnitude larger than previously reported values in exfoliated 2D materials. The strategy opens up new avenues for versatile applications of BP sheets and provides an effective method for tuning the physicochemical properties of other air-sensitive 2D semiconductors
Recommended from our members
Global, regional, and national burden of low back pain, 1990–2020, its attributable risk factors, and projections to 2050: a systematic analysis of the Global Burden of Disease Study 2021
Electrochemical Exfoliation to Produce High-Quality Black Phosphorus
To obtain high-quality two-dimensional (2D) materials from the bulky crystals, delamination under an externally controlled stimulus is crucial. Electrochemical exfoliation of layered materials requires simple instrumentation yet offers high-quality exfoliated 2D materials with high yields and features straightforward upscalability; therefore, it represents a key technology for advancing fundamental studies and industrial applications. Moreover, the solution processability of functionalized 2D materials enables the fabrication of (opto)electronic and energy devices via different printing technologies such as inkjet printing and 3D printing. This paper presents the electrochemical exfoliation protocol for the synthesis of black phosphorus (BP), one of the most promising emerging 2D materials, from its bulk crystals in a step-by-step manner, namely, cathodic electrochemical exfoliation of BP in the presence of N(C4H9)4∙HSO4 in propylene carbonate, dispersion preparation by sonication and subsequent centrifugation for the separation of flakes, and morphological characterization by scanning electron microscopy (SEM), atomic force microscopy (AFM), and transmission electron microscopy (TEM)
Resolution of syncope with treatment of sleep apnea (Journal of the American Board of Family Medicine (2008) 21, 5 (466-468) DOI 10.3122/jabfm.2009.05.090176)
The study of genetic diversity in a minicore collection of durum wheat genotypes using agro-morphological traits and molecular markers
The evaluation of genetic diversity in a gene pool contributes to the effective selection of genotypes and truncates the breeding time. In the present study, 96 durum wheat genotypes were evaluated for (1) genotypic diversity using two DNA marker systems: CAAT box-derived polymorphism (CBDP) and inter-simple sequence repeats (ISSR) markers and (2) phenotypic diversity using several drought-adaptive traits under rainfed conditions for two cropping seasons. Our results revealed that the ISSR primers produced 99 bands across the genotypes, the average of which was 6 fragments per primer, whereas CBDP primers generated 70 polymorphic bands, with an average of 5.3 fragments per primer. The values of marker index (MI) and polymorphism information content (PIC) indicated that CBDP markers were more efficient than ISSR markers for detection of genetic diversity in durum wheat. The average of PIC values for the CBDP and ISSR markers were 0.40 and 0.23, respectively. Based on the values of Shannon index (I) ICARDA population had a higher than CIMMYT population and the heterozygosis values confirmed these results. Dendrogram was created with a neighbor-joining clustering method. The studied genotypes were divided into five and seven groups based on data from the CBDP and ISSR markers, respectively, which was supported by principal coordinate analyses. The results of genotype by trait biplot analysis showed different patterns of interaction accessions and traits across years. High level of diversity among the studied accessions based on each studies trait was observed
Fabrication and characterization of metal-insulator-graphene diodes for microwave and THz application
Brain morphological alternation in chronic pain patients with neuropathic characteristics
Synthesis and characterization of carbon nanowalls on different substrates by radio frequency plasma enhanced chemical vapor deposition
A radio frequency plasma enhanced chemical vapor deposition system was used for the
successful growth of thin vertical carbon nanowalls, also known as vertical graphene, on
various substrates. Transmission electron microscopy studies confirmed the presence of
vertical graphene walls, which are tapered, typically consisting of 10 layers at the base
tapering off to 2 or 3 layers at the top. The sides of the walls are facetted at quantized
angles of 30 and the facetted sides are usually seamless. Growth occurs at the top open
edge which is not facetted. Hydrogen induced etching allows for nucleation of branch walls
apparently involving a carbon onion-like structure at the root base. Characterization by a
superconducting quantum interference device showed magnetic hysteresis loops and weak
ferromagnetic responses from the samples at room temperature and below. Temperature
dependence of the magnetization revealed a magnetic phase transition around T = 50 K
highlighting the coexistence of antiferromagnetic interactions as well as ferromagnetic
order.147491sciescopu