Graphene Nanocomposites as Innovative Materials for Energy Storage and Conversion-Design and Headways.

This review mainly addresses applications of polymer/graphene nanocomposites in certain significant energy storage and conversion devices such as supercapacitors, Li-ion batteries, and fuel cells. Graphene has achieved an indispensable position among carbon nanomaterials owing to its inimitable structure and features. Graphene and its nanocomposites have been recognized for providing a high surface area, electron conductivity, capacitance, energy density, charge-discharge, cyclic stability, power conversion efficiency, and other advanced features in efficient energy devices. Furthermore, graphene-containing nanocomposites have superior microstructure, mechanical robustness, and heat constancy characteristics. Thus, this state-of-the-art article offers comprehensive coverage on designing, processing, and applying graphene-based nanoarchitectures in high-performance energy storage and conversion devices. Despite the essential features of graphene-derived nanocomposites, several challenges need to be overcome to attain advanced device performance.

Intermolecular CH-π Electrons Interaction in Poly (9,9-dioctylfluorenyl-2,7-diyl) (PFO): An Experimental and Theoretical Study.

This study demonstrates the presence of CH-π interaction in poly [9,9-dioctylfluorenyl-2,7-diyl] (PFO-1) due to an aggregate formation of PFO-1 in the liquid state. The absorption spectra of PFO-1 in certain solvents at low concentrations showed a single band at 390 nm. However, when using high concentrations, a new band at 437 nm appeared. This band is due to the aggregate formation of PFO-1. The aggregate formation occurs as a result of the CH interaction of the n-alkyl side chains with π-electrons in the benzene ring. The optical characteristics of another conjugated polymer of poly [9,9-di-(2-ethylhexyl)-fluorenyl-2,7-diyl] (PFO-2) were investigated to confirm the CH-π interaction. The absorption showed only one wavelength at 390 nm without any new band at the end of the spectrum, even at higher concentrations and lower temperatures. The main reason for the absence of aggregate formation in PFO-2 is the sterical hindrance caused by the branched alkyl side chains. In addition, Density Functional Theory (DFT) was used to compute the HOMO-LUMO transitions, electron charge distribution, and frontier molecular orbitals for each polymer. The Mulliken charge distribution and demonstrated a notable difference in the reactivity of the alkyl side chain, confirming the higher ability of PFO-1 to form CH-π bonds. docking model emphasized that the band at 437 nm could be attributed to the interaction between CH in the n-alkyl side chain and π bonds in the aromatic rings of PFO-1.

Application of Synthesized Vanadium-Titanium Oxide Nanocomposite to Eliminate Rhodamine-B Dye from Aqueous Medium.

In this study, a V@TiO2 nanocomposite is examined for its ability to eliminate carcinogenic Rhodamine (Rh-B) dye from an aqueous medium. A simple ultrasonic method was used to produce the nanosorbent. In addition, V@TiO2 was characterized using various techniques, including XRD, HRTEM, XPS, and FTIR. Batch mode studies were used to study the removal of Rh-B dye. In the presence of pH 9, the V@TiO2 nanocomposite was able to remove Rh-B dye to its maximum extent. A correlation regression of 0.95 indicated that the Langmuir model was a better fit for dye adsorption. Moreover, the maximum adsorption capacity of the V@TiO2 nanocomposite was determined to be 158.8 mg/g. According to the thermodynamic parameters, dye adsorption followed a pseudo-first-order model. Based on the results of the study, a V@TiO2 nanocomposite can be reused for dye removal using ethanol.

Spectral Behavior of a Conjugated Polymer MDMO-PPV Doped with ZnO Nanoparticles: Thin Films.

The purpose of the presented study is to examine the impact of zinc oxide nanoparticles (ZnO NPs) on the spectrum features of poly [2-methoxy-5-(3',7'-dimethyloctyloxy)-1, 4-phenylenevinylene] (MDMO-PPV). The characteristics of the MDMO-PPV and doped ZnO NPS samples were assessed using several techniques. A set of solutions of MDMO-PPV in toluene that were doped with different ratio percentages of ZnO NPs was prepared to obtain thin films. Pristine and composite solutions were spin-coated on glass substrates. It was observed that MDMO-PPV had two distinct absorbance bands at 310 and 500 nm in its absorption spectrum. The UV-Vis spectrum was dramatically changed when 5% of ZnO NPs were added. The result showed a significant reduction in absorption of the band 500 nm, while 310 nm absorption increased rapidly and became more pronounced. Upon adding (10%) ZnONPs to the sample, no noticeable change was observed in the 500 nm band. However, the 310 nm band shifted towards the blue region. There is a dominant peak in the PL spectrum of MDMO-PPV in its pristine form around 575 nm and a smaller hump around 600 nm of the spectrum. The spectral profile at 600 nm and the intensity of both bands are improved by raising the ZnO NP concentration. These bands feature two vibronic transitions identified as (0-0) and (0-1). When the dopant concentration increased to the maximum dopant percentage (10%), the energy band gap values increased by 0.21 eV compared to the pristine MDMO-PPV. In addition, the refractive index (n) decreased to its lowest value of 2.30 with the presence of concentrations of ZnO NPs.

Sensitivity of Al-Doped Zinc-Oxide Extended Gate Field Effect Transistors to Low-Dose X-ray Radiation.

Herein, we investigated the applicability of thick film and bulk disk forms of aluminum-doped zinc oxide (AZO) for low-dose X-ray radiation dosimetry using the extended gate field effect transistor (EGFET) configuration. The samples were fabricated using the chemical bath deposition (CBD) technique. A thick film of AZO was deposited on a glass substrate, while the bulk disk form was prepared by pressing the collected powders. The prepared samples were characterized via X-ray diffraction (XRD) and field emission scanning electron microscope (FESEM) to determine the crystallinity and surface morphology. The analyses show that the samples are crystalline and comprise nanosheets of varying sizes. The EGFET devices were exposed to different X-ray radiation doses, then characterized by measuring the I-V characteristics pre- and post-irradiation. The measurements revealed an increase in the values of drain-source currents with radiation doses. To study the detection efficiency of the device, various bias voltages were also tested for the linear and saturation regimes. Performance parameters of the devices, such as sensitivity to X-radiation exposure and different gate bias voltage, were found to depend highly on the device geometry. The bulk disk type appears to be more radiation-sensitive than the AZO thick film. Furthermore, boosting the bias voltage increased the sensitivity of both devices.