Fabrication of composite transparent conductive electrodes based on silver nanowires.

Composite transparent conductive electrodes (C-TCEs) have recently been produced using low-cost techniques to keep up with the boom in the fabrication and development of optoelectronic devices. In this article, silver nanowires (AgNWs) were successfully synthesized by a simple hydrothermal method using different molecular weights MWs of poly (N-vinylpyrrolidone) (PVP). Graphene oxide (GO) was prepared using the modified Hummers' method and a reduction step was held on GO films to produce reduced GO (rGO). C-TCEs were fabricated by over-coating the AgNWs electrodes with rGO, or poly(3,4-ethylenedioxythiophene) polystyrene sulfonate to improve the roughness, surface energy, and sheet resistance. The influence of using lower and higher MWs of PVP on the yield, shape, and size of AgNWs was investigated. The results showed that using lower MW of PVP had a great effect on the yield, morphology, and aspect ratio of AgNWs with diameter of 46 nm and average length 12 µm. The optical, morphological, topographical, and electrical properties of TCEs were studied. AgNWs/rGO composite electrode provided the lowest surface roughness and surface energy of 250 nm and 47.95 mN/m, respectively, with a relatively high transparency of 78.2% at 550 nm light wavelength, and a low sheet resistance of 27 Ω/□.

Simple and Fast Microwave-Assisted Synthesis Methods of Nanocrystalline TiO2 and rGO Materials for Low-Cost Metal-Free DSSC Applications.

Nanocrystalline TiO2 and reduced graphene oxide (rGO) materials have been synthesized by a simple and low-cost microwave-assisted hydrothermal method and applied in dye-sensitized solar cells (DSSCs) as photoactive and metal-free counter electrodes, respectively. Different TiO2 nanocrystalline materials have been synthesized via the acid hydrolysis sol-gel method, followed by microwave hydrothermal treatment at 210 °C and 300 psi and at different microwave irradiation times (20, 30, 45, and 60 min) instead of the usual hydrothermal time of 12 h. The properties of the produced mesoporous nanocrystalline TiO2 are investigated in terms of their morphology, crystal structure, optical properties, and surface area behavior using relevant characterization techniques. Maximum specific surface area values (S BET) of 97.77 and 100.7 m2 g-1 are measured for TiO2, with the average crystallite sizes of 18.6 and 17.5 nm, at microwave irradiation times of 30 and 45 min, respectively. Different rGO samples have been prepared by the modified Hummers method, followed by microwave-assisted reduction at a temperature of 200 °C and pressure of 300 psi at different microwave irradiation times (3, 17, and 25 min). The physicochemical properties of the different rGO samples in terms of morphology, crystallization, and optical properties are characterized by TEM, XRD, and Raman spectroscopic analysis. The current density J sc of the fabricated DSSCs based on TiO2 as the photoelectrode and rGO as the counter electrode compared with DSSCs based on Pt as the counter electrode is found to be 11.25 and 9.28 mA cm-2, respectively. Although the overall power efficiency of the fabricated DSSCs based on rGO as the counter electrode is lower than that based on the Pt electrode, the former still exhibits promising prospects for replacing Pt with low-cost metal-free carbon-based DSSCs.

Correction to "Enhancement of Molten Nitrates Thermal Properties by Reduced Graphene Oxide and Graphene Quantum Dots".

[This corrects the article DOI: 10.1021/acsomega.0c01291.].

Enhancement of Molten Nitrate Thermal Properties by Reduced Graphene Oxide and Graphene Quantum Dots.

Eutectic molten salts are the most studied medium-high temperature thermal energy storage material due to their potential use in concentrated solar power plants. The aim of this work is to investigate the effect of using reduced graphene oxide (RGO) and graphene quantum dots (GQDs) on the thermal properties of eutectic molten salts. A binary nitrate eutectic mixture of NaNO3 and KNO3 was selected as a base material (BM) for nitrate/carbon-derivative composites. RGO and GQDs were individually mixed with the BM with different fractions ranged from 0.1 to 1.5 wt %. The results showed that RGO enhanced the thermal conductivity, heat of fusion, and total thermal energy storage capacity by 52.10%, 44.48%, and 10.44%, respectively. GQDs slightly improved the specific heat capacity for both solid and liquid phases by 2.53% and 3.13%, respectively. In addition, GQDs promoted the heat of fusion by 31.72% and raised the total TES capacity by 12.26%.