Search

Although perovskite solar cells have shown outstanding photovoltaic performance, there are still various obstacles that limit their performance and that remain as significant challenges. Weak optical absorption rate in the infrared region is a significant drawback for this kind of solar cell. In this paper, Au@SiO2@Graphene nanoparticles (NPs) as nano-photonic inclusions in the perovskite layer are proposed and investigated theoretically. Unlike conventional nanoparticles, these NPs exhibit strong, multiple plasmon resonances at low energies. The effect of geometrical parameters, periodicity, and the location of the Au@SiO2@Graphene NPs in the perovskite layer upon the performance of the PSCs are investigated. Under improved conditions, an absorption enhancement of 32% is obtained compared to pristine devices. Also, the result attained from coupled optical-electrical simulation of the improved device demonstrated 20.05% power conversion efficiency. These improvements have been achieved due to the plasmonic near-field enhancement effects of Au@SiO2@Graphene nanoparticles along with increased light-scattering from these NPs. [ABSTRACT FROM AUTHOR]

This paper studies the temperature dependence of the electrical resistivity of low-cost commercial graphene-based strips, made from a mixture of epoxy and graphene nanoplatelets. An equivalent homogenous resistivity model is derived from the joint use of experimental data and simulation results obtained by means of a full three-dimensional (3D) numerical electrothermal model. Three different types of macroscopic strips (with surface dimensions of cm2) are analyzed, differing in their percentage of graphene nanoplatelets. The experimental results show a linear trend of resistivity in a wide temperature range (−60°C to +60°C), and a negative temperature coefficient. The derived analytical model of temperature-dependent resistivity follows the simple law commonly adopted for conventional conducting materials, such us copper. The model is then validated by using the graphene strips as heating elements by exploiting the Joule effect. These results suggest that such materials can be used as thermistors in sensing or heating applications. [ABSTRACT FROM AUTHOR]

This paper investigates the nonlinear properties of graphene nanoplatelets (GNPs), decorated with Fe3O4 magnetic nanoparticles (MaNPs). Nanocomposite MaNP/GNP samples were prepared by a solvothermal method with three different MaNP loading concentrations of 17 wt%, 28 wt% and 40 wt%, and deposited on a metallic interdigitated electrode (IDE). Three different models are proposed to assess measurements, with the objective to explain the electronic transport in the nanocomposites. At first, a thermionic transport model is proposed to fit the DC nonlinear current–voltage characteristics for the three concentrations. It is observed that the barrier height decreases to 0.312, 0.310 and 0.281 eV, following a decrease in the MaNP loading. A second model, dynamic random resistor network (DRRN) further shows that the impedance of IDE increases following the decreasing MaNP loading rate, 40 wt% > 28 wt% > 17 wt%, and that charge transport takes place through a resistor–capacitor (RC) rectifying percolating network. Finally, impedance spectroscopy performed at different applied DC biases shows that a constant phase element (CPE) is necessary in the equivalent circuit in order to fit the Cole–Cole plot AC response of the IDE, instead of the classical parallel RC circuit. The presence of the CPE confirms the hypothesis of random phenomena occurring in the transport according to the DRRN model. CPE is associated with a spatial distribution of different RC circuits, due to disorderness that arises from inhomogeneities in the Fe3O4–GNP samples. [ABSTRACT FROM AUTHOR]

Vast research has been going on to improve the mechanical performance of carbon fiber reinforced polymers composite (CFRP) when subjected to quasi-static loading but investigation and modification of their dynamic behavior are still underdeveloped. This paper presents an experimental investigation on the effect of randomly dispersed graphene nanoplatelets (GNPs) on the mechanical properties of CFRP composites under dynamic loading. Four different mass fractions of GNPs, 0%, 0.5%, 1%, and 2%, were considered in the experiments. Specimens were tested experimentally using the split Hopkinson pressure bar device (SHPB) to examine their dynamic response and damage behavior at high strain rates. During the dynamic compression tests, a high-speed camera was used to monitor and record the damage kinetics. The experimental characterization showed that the integration of GNPs has greatly influenced the dynamic response and damage mechanism of the CFRP. Composite doped with 1% GNPs demonstrates the optimum enhancement of the mechanical properties of the composite specimens and shows an increase of the dynamic characteristics and fracture resistance. [ABSTRACT FROM AUTHOR]

Nano-patterning of graphene film by a novel approach making use of laser ablation generated pressure is presented in this paper. Arrays of nanoscale holes were fabricated by applying laser shock pressure on graphene film suspended on well trenches in silicon substrate. Round holes with diameters ranging from 50 to 200 nm on graphene film were successfully punched. The critical pressure was found to be dependent on the diameter of holes. The smaller the diameters, the higher the critical pressure, which was also captured by the molecular dynamic (MD) simulations. The laser shock based approach presented in this paper provides an effective way to pattern graphene film with nanoscale features in an easy, fast, and scalable manner. [ABSTRACT FROM AUTHOR]

In this perspective paper, we critically analyse the state-of-the-art of arc discharge technique of carbon nanoparticle synthesis. We discuss improving controllability of the arc discharge synthesis of carbon nanotubes, synthesis of graphene as well as general understanding of the synthesis process. Fundamental issues related to relationship between plasma parameters and carbon nanostructure characteristics are considered. Effects of electrical and magnetic fields applied during single-wall carbon nanotube synthesis in arc plasma are explored. Finally our personal opinion on what future trends will be in arc discharge synthesis is offered. [ABSTRACT FROM AUTHOR]

This review paper presents historical perspectives, recent advances and future directions in the multidisciplinary research field of plasma nanoscience. The current status and future challenges are presented using a three-dimensional framework. The first and the largest dimension covers the most important classes of nanoscale objects (nanostructures, nanofeatures and nanoassemblies/nanoarchitectures) and materials systems, namely carbon nanotubes, nanofibres, graphene, graphene nanoribbons, graphene nanoflakes, nanodiamond and related carbon-based nanostructures; metal, silicon and other inorganic nanoparticles and nanostructures; soft organic nanomaterials; nano-biomaterials; biological objects and nanoscale plasma etching. In the second dimension, we discuss the most common types of plasmas and plasma reactors used in nanoscale plasma synthesis and processing. These include low-temperature non-equilibrium plasmas at low and high pressures, thermal plasmas, high-pressure microplasmas, plasmas in liquids and plasma-liquid interactions, high-energy-density plasmas, and ionized physical vapour deposition as well as some other plasma-enhanced nanofabrication techniques. In the third dimension, we outline some of the 'Grand Science Challenges' and 'Grand Socio-economic Challenges' to which significant contributions from plasma nanoscience-related research can be expected in the near future. The urgent need for a stronger focus on practical, outcome-oriented research to tackle the grand challenges is emphasized and concisely formulated as from controlled complexity to practical simplicity in solving grand challenges. [ABSTRACT FROM AUTHOR]

The implantation and growth of metal nanoparticles on graphene nanosheets (GNS) leads directly to severe damage to the regular structure of the graphene sheets, which disrupts the extended p conjugation, resulting in an impaired device performance. In this paper, we describe a facile approach for achieving the lossless formation of graphene composite decorated with tiny cadmium sulfide quantum dots (QDs) with excellent nonlinear optical properties by using benzyl mercaptan (BM) as the interlinker. The mercapto substituent of BM binds to the CdS QDs during their nucleation and growth process, and then the phenyl comes into contact with the GNS via the p-p stacking interaction. Using this strategy, CdS QDs with an average diameter of 3 nm are uniformly dispersed over the surface of graphene, and the resulting QD-graphene composite exhibits excellent optical limiting properties, mainly contributed by nonlinear scattering and nonlinear absorption, upon both 532 and 1064 nm excitations, in the nanosecond laser pulse regime. [ABSTRACT FROM AUTHOR]