Efficiency Improvement Using Molybdenum Disulphide Interlayers in Single-Wall Carbon Nanotube/Silicon Solar Cells

This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).Molybdenum disulphide (MoS2) is one of the most studied and widely applied nanomaterials from the layered transition-metal dichalcogenides (TMDs) semiconductor family. MoS2 has a large carrier diffusion length and a high carrier mobility. Combining a layered structure of single-wall carbon nanotube (SWCNT) and MoS2 with n-type silicon (n-Si) provided novel SWCNT/n-Si photovoltaic devices. The solar cell has a layered structure with Si covered first by a thin layer of MoS2 flakes and then a SWCNT film. The films were examined using scanning electron microscopy, atomic force microscopy and Raman spectroscopy. The MoS2 flake thickness ranged from 5 to 90 nm while the nanosheet’s lateral dimensions size ranged up to 1 μm2. This insertion of MoS2 improved the photoconversion efficiency (PCE) of the SWCNT/n-Si solar cells by approximately a factor of 2The support of the Australian Research Council Discovery Program (DP150101354 and DP160101301) is gratefully acknowledged

Efficiency Improvement Using Molybdenum Disulphide Interlayers in Single-Wall Carbon Nanotube/Silicon Solar Cells

Molybdenum disulphide (MoS2) is one of the most studied and widely applied nanomaterials from the layered transition-metal dichalcogenides (TMDs) semiconductor family. MoS2 has a large carrier diffusion length and a high carrier mobility. Combining a layered structure of single-wall carbon nanotube (SWCNT) and MoS2 with n-type silicon (n-Si) provided novel SWCNT/n-Si photovoltaic devices. The solar cell has a layered structure with Si covered first by a thin layer of MoS2 flakes and then a SWCNT film. The films were examined using scanning electron microscopy, atomic force microscopy and Raman spectroscopy. The MoS2 flake thickness ranged from 5 to 90 nm while the nanosheet’s lateral dimensions size ranged up to 1 μm2. This insertion of MoS2 improved the photoconversion efficiency (PCE) of the SWCNT/n-Si solar cells by approximately a factor of 2

Chemical and Electrochemical Synthesis of Polypyrrole Using Carrageenan as a Dopant: Polypyrrole/Multi-Walled Carbon Nanotube Nanocomposites

In this article, iota-carrageenan (IC) and kappa-carrageenan (KC) are used as dopants for the chemical and electrochemical synthesis of polypyrrole (PPy). The composites of chemically synthesized PPy with multi-walled carbon nanotubes (MWNTs) were prepared using an in situ technique. Both the dialyzed and non-dialyzed IC and KC were used as dopants for electrochemical polymerization of pyrrole. Chemically synthesized PPy and PPy/MWNTs composites were studied by ultraviolet visible (UV-vis) absorption spectra to investigate the effect of the concentration and the incorporation of MWNTs. In addition, the electrical, thermal, mechanical, and microscopic characterizations of these films were performed to examine the effect of the dopants and MWNTs on these properties, along with their surface morphology. The films of electrochemically polymerized PPy were characterized using UV-vis absorption spectra, scanning electron microscopy, and cyclic voltammetry (CV). The results were then compared with the chemical polymerized PPy

Influence of Biopolymer Carrageenan and Glycerine on the Properties of Extrusion Printed Inks of Carbon Nanotubes

This article focuses on the preparation of extrusion printing composite inks of multiwall carbon nanotube (MWNT) dispersed separately in iota-carrageenan (IC) and glycerine (G) solution. Both composites (IC-MWNT and G-MWNT) showed shear-thinning behavior when their flow characteristics were tested. Conductive solid tracks/patterns of both printed composite inks were deposited on glass slide, PET (polyethylene terephthalate) sheet, and IC gel films substrates. The conductive patterns were characterized with microscopy, scanning electron microscopy (SEM), and profilometer. Moreover, their contact angle and electrical conductivity were measured. Profilometry showed that increased number of extruded layers gave increased cross-sectional area. SEM study showed that printing ink is embedded into the surface of IC film, discontinuous on glass slide and smoother on PET sheet. Conductivity of IC-MWNT track was 9 ± 1 S/m and that of G-MWNT was 2942 ± 84 S/m on glass substrate of one layer thick. This is because fewer carbon nanotubes (CNT) are present in G-MWNT track as confirmed by SEM study. The nature of substrate also affects the conductivity of printed patterns. The impressive result of conductivity of printed patterns of composite inks can make them useful for bioelectronic application

Novel Eco-Synthesis of PD Silver Nanoparticles: Characterization, Assessment of Its Antimicrobial and Cytotoxicity Properties

Nanomedicine is growing due to the development of new medical diagnostic tools and new nanostructure-based therapies that exert direct biological action or function as pharmacological carriers. Nanoparticles (NPs) synthesis provides an eco-friendly approach for different applications. Among NPs, silver NPs (AgNPs) are gaining considerable research interest due to their broad range of activity and their usability in the medical and biotechnology fields. In this study, a new AgNP synthesis method was developed using an aqueous pigeon dropping (PD) extract in silver nitrate (AgNO3). The rapid of AgNPs yield was detected visually. Analysis of UV-vis spectroscopy, energy-dispersive X-ray spectroscopy (EDX), dynamic light scattering (DLS) and electron microscopy (TEM) transmission showed a spherical or near spherical shape of AgNPs with mean size of 135 nm. AgNPs antimicrobial activities (anti-bacterial and anti-fungal) were determined using agar well diffusion method. These NPs further screened for anticancer activity in vitro using A-549 and MCF-7 cell lines. The results showed that the inhibition zone for the obtained PD AgNPs versus Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus were 26, 18, 17 and 15 mm, respectively. PD AgNPs showed the highest antifungal effect against Aspergillus flavus and the lowest effect against Penicillium griseofulvum. In vitro anti-cancer activities showed that the inhibitory concentration of 50% (IC50) of AgNPs was 10.3 ± 1.15 and 12.19 ± 0.75 µg mL−1 against A-549 and MCF-7 cancer cell lines, respectively

Design of sporopollenin-based functional ingredients for gastrointestinal tract targeted delivery

The design of intelligent delivery systems is becoming popular in the food ingredient sector. The increasing consumer demand for natural ingredients prompted researchers to look for new green solutions and use the goods of nature. Sporopollenin exine capsules (SECs) are obtained from plant pollen by washing out the proteins and genetic material. SECs are empty hollow particles that can be easily filled with hydrophobic and hydrophilic small molecular compounds, but also with proteins, enzymes, and even living probiotic bacteria. The release of compounds from the SECs is regulated by passive diffusion and can be further modulated by coating the SECs with a layer of lipids, proteins, or polysaccharides. SECs can also be functionalized to function as an intelligent delivery system that targets the intestinal mucus or the receptors located on epithelial cell membranes

An expeditious and environmentally benign synthesis of dispiro-3-phenylpyrrolothiazoles in ACI/EG eutectic mixture and its antioxidant and antimicrobial activities against urinary tract pathogens

Abstract The present study reveals the robust and facile methodology for the synthesis of massively selective dispiro-3-phenylpyrrolothiazole hybrids via one-pot 1,3-dipolar cycloaddition reaction by environmentally supported solvents and to evaluate their biological activities. The quaternary ammonium salt eutectic mixture, acetylcholine iodide-ethylene glycol (ACI/EG) medium brings an efficient environment for the synthesis of dispiropyrrolothiazole with excellent yield in shorter reaction time than imidazolium ionic liquids. The eutectic mixture was recovered and reused without any significant drop in their catalytic activity. Among the eight synthesized compounds 4a–h, halogen derivatives are exhibiting significant antimicrobial activities against selected uropathogens pathogens. Interestingly, chloro and bromo derivatives exhibits the minimum inhibitory concentration (MIC) of 12.5 μg/ml and 6.25 μg/ml towards Escherichia coli, Klebsiella pneumonia, and Staphylococcus aureus respectively. In addition, the IC50 values of DPPH radicals with synthesized compounds are interesting, particularly compounds 4a, 4d and 4e shows lower than the control BHA indicating their potent scavenging ability of free radicals

Enhanced hydrogen evolution reaction on highly stable titania-supported PdO and Eu2O3 nanocomposites in a strong alkaline solution

In this work, PdO/TiO and EuO/TiO nanocomposites (NCs) were synthesized using a new facile, template-free, and one-step solvothermal approach and characterized by several instrumentation techniques. X-ray photoelectron spectroscopy studies revealed the presence of oxidized form of the Pd and Eu nanoparticles within the NC materials (PdO and EuO). The two catalysts exhibited remarkable activity for the hydrogen evaluation reaction (HER) in a strong alkaline solution (4.0\ua0M NaOH) with PdO/TiO catalyst being the best, which recorded an exchange current density (j) of 0.26\ua0mA\ua0cm and a Tafel slope (β) of 125\ua0mV\ua0dec. Such parameters are not far from those recorded for a commercial Pt/C catalyst (0.71\ua0mA\ua0cm and 120\ua0mV\ua0dec) performed here under the same operating conditions. EuO/TiO catalyst recorded j and β values of 0.05\ua0mA\ua0cm and 135\ua0mV\ua0dec. The Tafel slopes 125 and 135\ua0mV\ua0dec calculated on the PdO/TiO and EuO/TiO catalysts suggest a HER kinetics controlled by the Volmer step. PdO/TiO catalyzed the HER with a high turnover frequency of 2.3 H/s at 0.2\ua0V versus the reversible hydrogen electrode, while EuO/TiO catalyst only measured a turnover frequency value of 1.25 H/s at the same overpotential. The two catalysts exhibited excellent stability and durability after 10\ua0000\ua0cycles and 72\ua0hours of controlled potential electrolysis at a high cathodic overpotential, reflecting their practical applicability. Scanning electron microscope and X-ray photoelectron spectroscopy examinations revealed that the morphology and chemistry of both catalysts were not altered as a result of the performed long-term stability and durability tests