Narrow Results

White light-absorbing materials are in high demand for catalysis and energy harvesting. Due to the UV (ultraviolet) light absorption capacity of graphene and zinc oxide (ZnO) nanoparticles, the light harvesting of the whole range of visible and near-IR (infra-red) light by utilizing these materials is a significant barrier. In this study, a graphene-ZnO nanoparticle composite was prepared from graphene and ZnO powder through a simple and novel hot solvent process at low temperatures without a catalyst or expensive instrumentation. The fabricated composite was found to absorb light efficiently at an extended range of wavelengths (400–1665nm) with strong absorption intensity. Notably, the in situ graphene-ZnO showed a considerably low intensity of absorption in the visible to the near-IR range; however, when the graphene and ZnO powder were combined as a graphene-ZnO composite by ex situ hot solvent synthesis process, the light absorption intensity significantly increased within the whole range. The observation in this study is the first one that indicates that the ex situ hot solvent process tunes the light absorption properties at the extreme level of the visible- to the near-IR range. The prepared composite also showed excellent electrical conductivity. The graphene powder was also prepared through a straightforward self-developed solvothermal process with the help of the exfoliating agent.

We review the recent developments in the field of photonic lattices emphasizing their unique properties for controlling linear and nonlinear propagation of light. We draw some important links between optical lattices and photonic crystals pointing towards practical applications in optical communications and computing, beam shaping, and biosensing.

We have obtained the optical properties of one-dimensional defective photonic crystals containing nanocomposite materials of Ag as a defect layer in UV region; the permittivity of nanocomposite materials depends on plasmon frequency of metal nanoparticles. Our analysis is based on the fundamentals of the transfer matrix method. We have investigated the effect of many parameters such as metal thickness, volume fraction, and defected dielectric materials on the intensity of a defect layer.

Irregular rod-like bismuth sulphochloride (BiSCl) was synthesized by a high efficiency process in which BiCl₃ and Bi₂S₃ were fully ground and mixed in N₂ atmosphere followed by a sintering at 227^∘C for 9 h to achieve crimson BiSCl powder. The products were characterized by X-ray powder diffraction (XRD) and scanning electronic microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX). The BiSCl is an n-type semiconductor with a bandgap of 1.9 eV. In the temperature range of 300–500 K, thermal conductivity, electrical conductivity, Seebeck coefficient and thermoelectric figure of merit ZT of the BiSCl were tested and calculated. It is resulted that the BiSCl has a thermal conductivity of 0.45 Wm⁻¹K⁻¹ at 500 K and a Seebeck coefficient of −579 μVK⁻¹ at 400 K. This work will help inform future in-depth studies on possible applications of BiSCl in the fields of thermoelectricity, optoelectronics and photocatalyticity.

In the quantum system of nanolayer (NL) on silicon, the bandgap energy obviously increases with the decrease of NL thickness, where the quantum confinement (QC) effect plays the main role as the thickness of Si NL changes along with (100), (110) and (111) directions, respectively. And the simulation result demonstrated that the direct bandgap can be obtained as the NL with (001) direction is thinner than 10 nm on Si surface. However, it is discovered in the simulated calculation that the QC effect disappears as the NL thickness arrives at the size of the monoatomic layer, in which its bandgap sharply decreases, where the abrupt change effect in bandgap energy occurs near-ideal 2D-layer. In the experiment, we fabricated the Si NL structure by using electron beam irradiation and laser deposition methods, in which a novel way was used to control the NL thickness by modulating irradiation time of the electron beam. The new effect should have a good application on a photonic-electronic chip of silicon.