Effect of copper doping on plasmonic nanofilms for high performance photovoltaic energy applications.

In the current era, alternative but environment-friendly sources of energy have gained attention to meet the growing energy demands. In particular, the focus of research has been solar energy and using it to fulfill energy demands. Solar energy is either directly converted into electrical energy or stored for later use. Solar cells are a practical way to turn solar energy into electrical energy. Various materials are being investigated to manufacture solar cell devices that can absorb a maximum number of photons present in sunlight. The present study reports thermally evaporated in situ Cu-doped SnS photon absorber thin films with tunable physical properties. This study mainly explored the effects of changing Cu concentrations on the physical features of light absorption of SnS thin films. The thin films were formed by simultaneous resistive heating of Cu and SnS powders on glass substrates at 150 °C. The X-ray diffraction patterns revealed pure SnS thin films having orthorhombic polycrystalline crystal structures oriented preferentially along the (111) plane. Raman spectroscopy confirmed this phase purity. Photoconductivity studies showed phase dependence on Cu content that improved with increasing concentrations of Cu. The optical bandgap energy was also found to be dependent on Cu content and was observed at 1.10-1.47 eV for SnS thin films with variation in the Cu content, i.e., 0-18%. According to the hot probe method, all films displayed p-type conductivity for the substitution of Cu metal atoms. These findings demonstrated that the prepared thin films are substantial candidates as low-cost, suitably efficient, thin-film solar cells featuring environmentally-friendly active layers that absorb sunlight.

Ultrahigh-Porosity MgO Microparticles for Heat-Energy Storage.

Continuous industrial development has increased the demand of energy. Inevitably, the development of energy sources is steadily progressing using various methods. Rather than establishing a new energy source, a system for storing waste heat generated by industry has now been accepted as a useful strategy. Among such systems, the hydration and dehydration reactions of MgO/Mg(OH)2  are eco-friendly, have relatively low toxicity and risk, and have a large reserves. Therefore, it is a promising candidate for a heat-storage system. In this study, ultrahigh-porosity particles are used to maximize the heat-storage efficiency of pure MgO. Due to its large surface area, the heat storage rate is 90.3% of the theoretical value and the reaction rate is very high. In addition, as structural collapse, likely to be caused by volume changes between reactions, is blocked as the porous region is filled and emptied, the cycle stability is secured. Ultrahigh-porosity MgO microparticles can be used to build eco-friendly heat-storage systems.

Organic Dispersion of Mo3Se3- Single-Chain Atomic Crystals Using Surface Modification Methods.

In this study, single-chain atomic crystals (SCACs), Mo3Se3-, which can be uniformly dispersed, with an atomically thin diameter of ∼0.6 nm were modified to disperse in an organic solvent. Various surfactants were chosen to provide steric hindrance to aqueous-dispersed Mo3Se3- by modifying the surface of Mo3Se3-. The organic dispersions of surface-modified Mo3Se3- SCACs in nonpolar solvent (toluene, benzene, and chloroform) were stable with a uniform diameter of 2 nm, and they have enhanced stability from oxidation (>10 days). With the surfactants that have a polystyrene tail group (PS-NH2), the surface-modified Mo3Se3- SCAC showed high compatibility with a polystyrene polymer matrix. Using the surface-modified Mo3Se3- SCAC, a homogeneous Mo3Se3-/polystyrene/toluene organogel was prepared. More importantly, the Mo3Se3-/polystyrene organogel exhibits significantly enhanced mechanical properties, with the improvement of 202.27% and 279.52% for tensile strength and elongation, respectively, compared with that of the pure organogel. The surface-modified Mo3Se3- had a similar structure with a polymer matrix, and the properties of the polymer can be improved even with a small addition of Mo3Se3-.

The effect of Mn and Co dual-doping on the structural, optical, dielectric and magnetic properties of ZnO nanostructures.

This paper addresses the effect of Mn (2%, fixed) and Co (2, 4, and 6%, varied) substitution on the structural, optical, dielectric and magnetic responses of ZnO nanoparticles synthesized by the co-precipitation chemical route. The X-ray diffraction analysis confirms the hexagonal wurtzite structure of ZnO. The incorporation of co-doping in the ZnO host, indicated by peak shifting in the XRD patterns, enhanced the crystallite size of the Mn/Co dual-doped ZnO nanoparticles. The FTIR spectra show a characteristic peak around 875 cm-1 assigned to Zn-O stretching, this validates the formation of the wurtzite structure of ZnO. Raman spectroscopy reveals the characteristic band of the wurtzite structure of ZnO nanoparticles along with coupled vibration modes of Mn/Co with the donor defect states in the doped samples. Enhanced optical absorption in the visible region and a significant red-shift in the absorption band edge were found due to doping. The optical band gap is found to decrease from 3.45 eV to 3.15 eV when Co doping increases up to 6%. The dielectric properties, strongly frequency-dependent, decrease with increasing Co doping while the electrical conductivity increases. Ferromagnetism is observed in all the doped samples, and its origin is attributed to an increase in oxygen vacancies which form bound magnetic polarons. It can be inferred that the doping of Mn and Co can be an effective tool to tune the physical properties of ZnO nanoparticles for potential spintronics and high-frequency applications.

A study on the bio-applicability of aqueous-dispersed van der Waals 1-D material Nb2Se9 using poloxamer.

In this research, dispersion of a new type of one-dimensional inorganic material Nb2Se9, composed of van der Waals bonds, in aqueous solution for bio-application study were studied. To disperse Nb2Se9, which exhibits hydrophobic properties in water, experiments were carried out using a block copolymer (poloxamer) as a dispersant. It was confirmed that PPO, the hydrophobic portion of Poloxamer, was adsorbed onto the surface of Nb2Se9, and PEO, the hydrophilic portion, induced steric hinderance to disperse Nb2Se9 to a size of 10 nm or less. To confirm the adaptability of muscle cells C2C12 to the dispersed Nb2Se9 using poloxamer 188 as dispersant, a MTT assay and a live/dead assay were performed, demonstrating improvement in the viability and proliferation of C2C12 cells.

Aqueous Dispersion of One-Dimensional van der Waals Material Mo6S3I6 with the Charge Type of the Hydrophobic Dispersant Tail.

Aqueous dispersion of van der Waals bonded one-dimensional materials Mo6S3I6 with hydrophobic surfaces has been studied. The surface charge of the dispersed Mo6S3I6 is controlled from negative to positive by the charge type of dispersant tail (anionic, SDS and NaDDBS; cationic, CTAB; nonionic, Poloxamer 407), and through this, it is possible to deposit the dispersed Mo6S3I6 in nanosized by electrophoretic deposition at a desired position. When a flexible device was manufactured by transferring Mo6S3I6, it was confirmed that electrical conductivity can be measured in 40% of elongation and more than 1000 times cyclic test.