Low Temperature Growth of Graphene on Glass by Carbon-Enclosed Chemical Vapor Deposition Process and Its Application as Transparent Electrode

A novel carbon-enclosed chemical vapor deposition (CE-CVD) to grow high quality monolayer graphene on Cu substrate at a low temperature of 500 °C was demonstrated. The quality of the grown graphene was investigated by Raman spectra, and the detailed growth mechanism of high quality graphene by the CE-CVD process was investigated in detail. In addition to growth of high quality monolayer graphene, a transparent hybrid few-layer graphene/CuNi mesh electrode directly synthesized by the CE-CVD process on a conventional glass substrate at the temperature of 500 °C was demonstrated, showing excellent electrical properties (∼5 Ω/□ @ 93.5% transparency) and ready to be used for optical applications without further transfer process. The few-layer graphene/CuNi mesh electrode shows no electrical degradation even after 2 h annealing in pure oxygen at an elevated temperature of ∼300 °C. Furthermore, the few-layer graphene/CuNi mesh electrode delivers an excellent corrosion resistance in highly corrosive solutions such as electroplating process and achieves a good nucleation rate for the deposited film. Findings suggest that the low temperature few-layer graphene/CuNi mesh electrode synthesized by the CE-CVD process is an excellent candidate to replace indium tin oxide (ITO) as transparent conductive material (TCM) in the next generation

<i>Romantic Story or Raman Scattering?</i> Rose Petals as Ecofriendly, Low-Cost Substrates for Ultrasensitive Surface-Enhanced Raman Scattering

In this Article, we present a facile approach for the preparation of ecofriendly substrates, based on common rose petals, for ultrasensitive surface-enhanced Raman scattering (SERS). The hydrophobic concentrating effect of the rose petals allows us to concentrate metal nanoparticle (NP) <i>aggregates</i> and analytes onto their surfaces. From a systematic investigation of the SERS performance when using upper and lower epidermises as substrates, we find that the lower epidermis, with its quasi-three-dimensional (quasi-3D) nanofold structure, is the superior biotemplate for SERS applications. The metal NPs and analytes are both closely packed in the quasi-3D structure of the lower epidermis, thereby enhancing the Raman signals dramatically within the depth of focus (DOF) of the Raman optical system. We have also found the effect of the pigment of the petals on the SERS performance. With the novel petal-based substrate, the SERS measurements reveal a detection limit for rhodamine 6G below the femtomolar regime (10^–15 M), with high reproducibility. Moreover, when we employ an upside-down drying process, the unique effect of the Wenzal state of the hydrophobic petal surface further concentrate the analytes and enhanced the SERS signals. Rose petals are green, natural materials that appear to have great potential for use in biosensors and biophotonics

Transfer-Free Growth of Atomically Thin Transition Metal Disulfides Using a Solution Precursor by a Laser Irradiation Process and Their Application in Low-Power Photodetectors

Although chemical vapor deposition is the most common method to synthesize transition metal dichalcogenides (TMDs), several obstacles, such as the high annealing temperature restricting the substrates used in the process and the required transfer causing the formation of wrinkles and defects, must be resolved. Here, we present a novel method to grow patternable two-dimensional (2D) transition metal disulfides (MS₂) directly underneath a protective coating layer by spin-coating a liquid chalcogen precursor onto the transition metal oxide layer, followed by a laser irradiation annealing process. Two metal sulfides, molybdenum disulfide (MoS₂) and tungsten disulfide (WS₂), are investigated in this work. Material characterization reveals the diffusion of sulfur into the oxide layer prior to the formation of the MS₂. By controlling the sulfur diffusion, we are able to synthesize continuous MS₂ layers beneath the top oxide layer, creating a protective coating layer for the newly formed TMD. Air-stable and low-power photosensing devices fabricated on the synthesized 2D WS₂ without the need for a further transfer process demonstrate the potential applicability of TMDs generated via a laser irradiation process

Large-Scale Micro- and Nanopatterns of Cu(In,Ga)Se₂ Thin Film Solar Cells by Mold-Assisted Chemical-Etching Process

A reactive mold-assisted chemical etching (MACE) process through an easy-to-make agarose stamp soaked in bromine methanol etchant to rapidly imprint larger area micro- and nanoarrays on CIGS substrates was demonstrated. Interestingly, by using the agarose stamp during the MACE process with and without additive containing oil and triton, CIGS microdome and microhole arrays can be formed on the CIGS substrate. Detailed formation mechanisms of microstructures and the chemical composition variation after the etching process were investigated. In addition, various microand nanostructures were also demonstrated by this universal approach. The microstructure arrays integrated into standard CIGS solar cells with thinner thickness can still achieve an efficiency of 11.22%, yielding an enhanced efficiency of ∼18% compared with that of their planar counterpart due to an excellent absorption behavior confirmed by the simulation results, which opens up a promising way for the realization of high-efficiency micro- or nanostructured thin-film solar cells. Finally, the complete dissolution of agarose stamp into hot water demonstrates an environmentally friendly method by the mold-assisted chemical etching process through an easy-to-make agarose stamp

Enhanced Conversion Efficiency of Cu(In,Ga)Se₂ Solar Cells via Electrochemical Passivation Treatment

Defect control in Cu­(In,Ga)­Se₂ (CIGS) materials, no matter what the defect type or density, is a significant issue, correlating directly to PV performance. These defects act as recombination centers and can be briefly categorized into interface recombination and Shockley–Read–Hall (SRH) recombination, both of which can lead to reduced PV performance. Here, we introduce an electrochemical passivation treatment for CIGS films that can lower the oxygen concentration at the CIGS surface as observed by X-ray photoelectron spectrometer analysis. Temperature-dependent <i>J–V</i> characteristics of CIGS solar cells reveal that interface recombination is suppressed and an improved rollover condition can be achieved following our electrochemical treatment. As a result, the surface defects are passivated, and the power conversion efficiency performance of the solar cell devices can be enhanced from 4.73 to 7.75%

Effect of immunization with DENV NS1, JEV NS1, ΔC NS1 and DJ NS1 proteins on bleeding time in mice.

<p>C3H/HeN mice (n = 6/group) were intraperitoneally (i.p.) immunized five times with DENV NS1, JEV NS1, ΔC NS1 or DJ NS1 proteins. The mouse tail bleeding time was determined 3 days after the last immunization. Prolonged bleeding time was observed in DENV NS1-immunized mice, but not in ΔC NS1- and DJ NS1-immunized mice. * <i>P</i><0.05, ** <i>P</i><0.01.</p

Protection against Dengue Virus Infection in Mice by Administration of Antibodies against Modified Nonstructural Protein 1

<div><p>Background</p><p>Infection with dengue virus (DENV) may cause life-threatening disease with thrombocytopenia and vascular leakage which are related to dysfunction of platelets and endothelial cells. We previously showed that antibodies (Abs) against DENV nonstructural protein 1 (NS1) cross-react with human platelets and endothelial cells, leading to functional disturbances. Based on sequence homology analysis, the C-terminal region of DENV NS1 protein contains cross-reactive epitopes. For safety in vaccine development, the cross-reactive epitopes of DENV NS1 protein should be deleted or modified.</p><p>Methodology/Principal Findings</p><p>We tested the protective effects of Abs against full-length DENV NS1, NS1 lacking the C-terminal amino acids (a.a.) 271-352 (designated ΔC NS1), and chimeric DJ NS1 consisting of N-terminal DENV NS1 (a.a. 1-270) and C-terminal Japanese encephalitis virus NS1 (a.a. 271-352). The anti-ΔC NS1 and anti-DJ NS1 Abs showed a lower binding activity to endothelial cells and platelets than that of anti-DENV NS1 Abs. Passive immunization with anti-ΔC NS1 and anti-DJ NS1 Abs reduced DENV-induced prolonged mouse tail bleeding time. Treatment with anti-DENV NS1, anti-ΔC NS1 and anti-DJ NS1 Abs reduced local skin hemorrhage, controlled the viral load of DENV infection <i>in vivo</i>, synergized with complement to inhibit viral replication <i>in vitro</i>, as well as abolished DENV-induced macrophage infiltration to the site of skin inoculation. Moreover, active immunization with modified NS1 protein, but not with unmodified DENV NS1 protein, reduced DENV-induced prolonged bleeding time, local skin hemorrhage, and viral load.</p><p>Conclusions/Significance</p><p>These results support the idea that modified NS1 proteins may represent an improved strategy for safe and effective vaccine development against DENV infection.</p></div

Large Scale and Orientation-Controllable Nanotip Structures on CuInS₂, Cu(In,Ga)S₂, CuInSe₂, and Cu(In,Ga)Se₂ by Low Energy Ion Beam Bombardment Process: Growth and Characterization

One-step facile methodology to create nanotip arrays on chalcopyrite materials (such as CuInS₂, Cu­(In,Ga)­S₂, CuInSe₂, and Cu­(In,Ga)­Se₂) via a low energy ion beam bombardment process has been demonstrated. The mechanism of formation for nanotip arrays has been proposed by sputtering yields of metals and reduction of metals induced by the ion beam bombardment process. The optical reflectance of these chalcopyrite nanotip arrays has been characterized by UV–vis spectrophotometer and the efficient light-trapping effect has been observed. Large scale (∼4′′) and high density (10¹⁰ tips/cm²) of chalcopyrite nanotip arrays have been obtained by using low ion energy (< 1 kV), short processing duration (< 30 min), and template-free. Besides, orientation and length of these chalcopyrite nanotip arrays are controllable. Our results can be the guide for other nanostructured materials fabrication by ion sputtering and are available for industrial production as well

Anti-DENV NS1, anti-ΔC NS1 and anti-DJ NS1 Abs reduce DENV-induced hemorrhage in mice.

<p>(a)–(f) show skin samples from mice. The numbers of mice with hemorrhage/total numbers of mice inoculated in each group are indicated. (g)–(l) show the red blood cell extravasation in skin sections. The arrows indicate the regions of red blood cell extravasation. (Magnification: ×200; bar = 100 μm)</p

Anti-ΔC NS1 and anti-DJ NS1 Abs reduce DENV-induced prolonged bleeding time in mice.

<p>Control IgG, anti-DENV NS1, anti-ΔC NS1 or anti-DJ NS1 Abs (100 μg/mouse) were i.p. injected to C3H/HeN mice, and one day later 9×10⁷ pfu/mouse of DENV were intradermally (i.d.) inoculated in mice. On days one and two post-infection, mice were i.p. injected with 100 μg Abs and the bleeding time was determined on day 3. (n = 5 for medium control and anti-DJ NS1 Abs groups, n = 6 for DENV infection alone, control IgG, anti-DENV NS1 and anti-ΔC NS1 Abs groups) * <i>P</i><0.05.</p