The Surface Photogalvanic and Photon Drag Effects in Ag/Pd Metal-Semiconductor Nanocomposite

We performed the investigation of the polarization-sensitive photocurrent generated in silver-palladium metal-semiconductor nanocomposite films under irradiation with nanosecond laser pulses at the wavelength of 2600 nm. It is shown that in both the transverse and the longitudinal configuration, the surface photogalvanic (SPGE) and photon drag effects (PDE) contribute to the observed photocurrent. However, the temporal profile of the transverse photocurrent pulse is monopolar at any polarization and angle of incidence, while the temporal profile of the longitudinal photocurrent pulse depends on the polarization of the excitation beam. Specifically, the irradiation of the film with the s-polarized excitation beam produces a monopolar photoresponse, while at p-polarized excitation, the photoresponse is bipolar, having a short front and long tail. Obtained experimental results are in agreement with the developed phenomenological theory, which describes transverse and longitudinal photocurrents due to SPGE and PDE in terms of relevant second-order nonlinear susceptibilities and allows us to obtain their dependences on the angle of incidence and polarization of the excitation laser beam. The pronounced dependence of the photocurrent on the angle of incidence and polarization of the excitation beam opens avenues toward the development of polarization- and position-sensitive detectors for industrial and space applications.

Domestic microwave assisted one-step co-precipitation of Ag–CuO nanocomposite of Cu/Ag ratio optimized for photocatalysis and comparison with blending CuO with Ag nanoparticles

The Ag–CuO metal–semiconductor nanocomposite (NC) is an important component in various nanomaterial-based applications. Several approaches have been studied to facilitate its synthesis. However, most of them encounter some drawbacks. In the present work, we show the synthesis of Ag–CuO NCs through one-pot co-precipitation with the aid of simple starting chemicals and measures including metal nitrates, hexamine, agar, and domestic microwave heating. Photocatalyzed degradation of Congo Red in addition to the structural and optical characteristics show that this method is successful in production of the Schottky barrier in Ag–CuO NCs with improved photocatalytic activity (PCA). Changing the Cu content shows that the NC is not successfully formed at low Cu mol%. Consequently, the PCA of Ag–CuO of low Cu (2%–6%) lies within 4.5 × 10−4 – 5.1 × 10−4 min−1, which is even lower than those of plain Ag and CuO nanoparticles (6.0 × 10−4 – 8.1 × 10−4 min−1, respectively). 60 mol% was the optimum Cu content with the highest PCA (18.8 × 10−4 min−1). Blending plain Ag and CuO nanoparticles to mimic the co-precipitated 60 mol% Ag–CuO showed very low PCA, even lower than the plain Ag and CuO, which once again confirms the efficiency of the simple one-pot co-precipitation approach in producing Ag–CuO with the Schottky barrier and promoted PCA.

An Overview on Graphene-Metal Oxide Semiconductor Nanocomposite: A Promising Platform for Visible Light Photocatalytic Activity for the Treatment of Various Pollutants in Aqueous Medium

Graphene is one of the most favorite materials for materials science research owing to its distinctive chemical and physical properties, such as superior conductivity, extremely larger specific surface area, and good mechanical/chemical stability with the flexible monolayer structure. Graphene is considered as a supreme matrix and electron arbitrator of semiconductor nanoparticles for environmental pollution remediation. The present review looks at the recent progress on the graphene-based metal oxide and ternary composites for photocatalysis application, especially for the application of the environmental remediation. The challenges and perspectives of emerging graphene-based metal oxide nanocomposites for photocatalysis are also discussed.

Biosynthesized Ag Nanoparticles: a Promising Pathway for Bandgap Tailoring

The unrivaled features and prospective applications promote graphene as a potent contender for next-generation nanodevices. But the realization of a tunable bandgap structure for zero-bandgap graphene at all times persists as a dilemma. In this work, a green approach is adopted for the bandgap modulation of graphene oxide (GO). The biosynthesized silver nanoparticles (AgNPs) were introduced into the graphene matrix, and hence the bandgap was tailored for the formation of a semiconductor composite. The bare GO that has got a bandgap of 3.41 eV was tuned to 2.33 eV on the addition of AgNPs. The preparation of AgNPs using fruit extract of cyanococcus make the process greener, safer, and cost-effective. This paper intends to open a new venture towards the environment safe synthesis of semiconductor nanocomposite necessitate for optoelectronic and photovoltaic technologies.