Nickel is one of the most commonly used catalysts for the growth of carbon which is clearly dependent on the growth temperature. Our findings reconcile the longstanding debate on the contradictory models (i.e. Ni-assisted growth, Ni 3 C 1-x -assisted growth and Ni 3 C-assisted growth) for the catalytic growth CNFs.

Layered black phosphorus (BP) has been expected to be a promising material for future electronic and optoelectronic applications since its discovery. However, the difficulty in mass fabricating layered air-stable BP severely obstructs its potential industry applications. Here, we report a new BP chemical modification method to implement all-solution-based mass production of layered air-stable BP. This method uses the combination of two electron-deficient reagents 2,2,6,6-tetramethylpiperidinyl-N-oxyl (TEMPO) and triphenylcarbenium tetrafluorobor ([Ph3C]­BF4) to accomplish thinning and/or passivation of BP in organic solvent. The field-effect transistor and photodetection devices constructed from the chemically modified BP flakes exhibit enhanced performances with environmental stability up to 4 months. A proof-of-concept BP thin-film transistor fabricated through the all-solution-based exfoliation and modification displays an air-stable and a typical p-type transistor behavior. This all-solution-based method improves the prospects of BP for industry applications.

No abstract

Fe3C-C core-shell nanoparticles were fabricated on a large scale by metal-organic chemical vapor deposition at 700 °C with ferric acetylacetonate as the precursor. Analysis results of x-ray diffraction, transmission electron microscope and Raman spectroscope showed that the Fe3C cores with an average diameter of ∼35 nm were capsulated by the graphite-like C layers with the thickness of 2-5 nm. The comparative experiments revealed that considerable Fe3O4-Fe3C core-shell nanoparticles and C nanotubes were generated simultaneously at 600 and 800 °C, respectively. A formation mechanism was proposed for the as-synthesized core-shell nanostructures, based on the temperature-dependent catalytic activity of Fe3C nanoclusters and the coalescence process of Fe3C-C nanoclusters. The Fe3C-C core-shell nanoparticles exhibited a saturation magnetization of 23.6 emu g(-1) and a coercivity of 550 Oe at room temperature.

Ni-assisted thermal chemical vapor deposition (TCVD) is one of the most common techniques for the growth of carbon nanofibres/nanotubes (CNFs/CNTs). However, some fundamental issues related to the catalytic growth of CNFs/CNTs, such as the low-limit growth temperature, the limiting steps and the state of Ni, are still controversial. Here, we report the growth of CNFs at 300 °C; that is the lowest temperature for the growth of CNFs by TCVD using Ni as the catalyst so far. The results showed that the Ni existed in rhombohedral Ni3C, not in the normal form of face-centered cubic Ni, and the C atoms for building the CNFs were precipitated from the (001) planes of the faceted Ni3C nanoparticles. The CNFs are believed to be formed by the decomposition-formation cycle of metastable Ni3C that has a low-limit decomposition temperature of about 300 °C. Our results strongly suggest that TCVD is a valuable tool for the synthesis of CNFs/CNTs at temperatures below 400 °C, which is generally considered as the upper-limit temperature for fabricating complementary metal oxide semiconductor devices but is the low-limit temperature for growing CNFs/CNTs by TCVD at present.

No abstract

BackgroundThis study investigated the function of SMAD3 (SMAD family member 3) in regulating PAX6 (paired box 6) in non-small cell lung cancer.MethodsFirst, qRT-PCR was employed to detect SMAD3 expression in cancer tissues along with normal tissues and four cell lines, including BEAS-2B, H125, HCC827 and A549 cells. SMAD3 was knocked down by small interference RNA (siRNA), and then its expression was determined via qRT-PCR and Western blot analysis. The correlation between SMAD3 and PAX6 was determined by double luciferase reporter experiments and chromatin immunoprecipitation (ChIP) assay. Cell viability was evaluated by CCK-8 and colony forming assays, while cell migration and invasion were detected by Transwell analysis.ResultsSMAD3 and PAX6 were upregulated in lung cancer tissues and cancer cells. Knocking down SMAD3 and PAX6 by transfection with siRNAs specifically suppressed the expression of SMAD3 and PAX6 mRNA and protein levels. SMAD3 could promote PAX6 transcriptional activity by binding to its promoter. Reduced expression of SMAD3 led to the downregulation of PAX6 mRNA and protein levels along with decreased cell migration, invasion, proliferation and viability in A549 and HCC827 cells. PAX6 overexpression altered the si-SMAD3-induced inhibition of cell migration, invasion, proliferation and viability in A549 and HCC827 cells. Additionally, PAX6 knockdown alone also repressed the cell migration, invasion, proliferation and viability of the cell lines.ConclusionsSMAD3 promotes the progression of non-small cell lung cancer by upregulating PAX6 expression.Electronic supplementary materialThe online version of this article (10.1186/s12931-018-0948-z) contains supplementary material, which is available to authorized users.

Efficient modulation of carrier concentration is fundamentally important for tailoring the electronic and photoelectronic properties of semiconducting materials. Photoinduced doping is potentially a promising way to realize such a goal for atomically thin nanomaterials in a rapid and defect-free manner. However, the wide applications of photoinduced doping in nanomaterials are severely constrained by the low doping concentration and poor stability that can be reached. Here, we propose a novel photoinduced doping mechanism based on the external photoelectric effect of metal coating on nanomaterials to significantly enhance the achievable doping concentration and stability. This approach is preliminarily demonstrated by an MX (M is Mo or Re; X is S or Se) nanoflake modified through a simple process of sequentially depositing and annealing an Au layer on the surface of the flake. Under ultraviolet (UV) light illumination, the modified MX achieves degenerated n-type doping density of 10 cm rapidly according to the experimentally observed >10 times increment in the channel current. The doping level persists after the removal of UV illumination with a nonobservable decrease over 1 day in vacuum (less than 23% over 7 days under an ambient environment). This photoinduced doping approach may contribute a major leap to the development of photocontrollable nanoelectronics.