scholarly journals Optical Band Gap and Thermal Diffusivity of Polypyrrole-Nanoparticles Decorated Reduced Graphene Oxide Nanocomposite Layer

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Amir Reza Sadrolhosseini ◽  
Suraya Abdul Rashid ◽  
A. S. M. Noor ◽  
Alireza Kharazmi ◽  
H. N. Lim ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Thermal Diffusivity ◽  
Band Gap ◽  
Reduced Graphene Oxide ◽  
Optical Band Gap ◽  
Nanocomposite Layer ◽  
Reduced Graphene ◽  
Visible Spectra ◽  
Polypyrrole Nanoparticles ◽  
Uv Visible

A polypyrrole-nanoparticles reduced graphene oxide nanocomposite layer was prepared using electrochemical method. The prepared samples were characterized using Fourier transform infrared spectroscopy, field emission scanning electron microscopy, and UV-visible spectroscopy. The band gap of nanocomposite layers was calculated from UV-visible spectra and the thermal diffusivity of layers was measured using a photoacoustic technique. As experimental results, the optical band gap was in the range between 3.580 eV and 3.853 eV, and thermal diffusivity was increased with increasing the layer thickness from 2.873 cm2/s to 12.446 cm2/s.

The Role of Reduced Graphene Oxide Concentration as Ablated Material on Optical Properties of Graphene Quantum Dots

2019 ◽  
Vol 948 ◽  
pp. 267-273 ◽  
Author(s):  
Fiqhri Heda Murdaka ◽  
Ahmad Kusumaatmaja ◽  
Isnaeni ◽  
Iman Santoso
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Graphene Oxide ◽  
Band Gap ◽  
Reduced Graphene Oxide ◽  
Optical Band Gap ◽  
Graphene Quantum Dots ◽  
Absorption Peak ◽  
Oxygen Defect ◽  
Reduced Graphene

We report the synthesize of Graphene Quantum Dots (GQDs) using ablation method with reduced Graphene Oxide (rGO) solution as a starting material. We have varied the concentration of rGO as following: 0.5, 2, 5 mg/ml and then have ablated them using 800 nm Ti-Sapphire femtosecond laser to obtain GQDs. From the UV-Vis data, we observed that the more concentration of rGO is being ablated, the more secondary absorption peak at 255.1 nm appeared. This secondary absorption peak is a characteristic of n-π* bonding due to the presence of oxygen defect which occurs as a result of the interaction between the laser and the water in rGO solution. We conclude that the population of oxigen defect in GQDs is increasing, following the increase of rGO concentration and could alter the optical properties of GQD. On the other hand, using Tauc’s plot, we confirm that the increase of rGO concentration as the ablated material does not alter GQDs optical band gap. However, it will slightly reduce both, direct and indirect Oxygen defect related optical band gap.

Functionalized reduced graphene oxide with tunable band gap and good solubility in organic solvents

Carbon ◽  
2019 ◽  
Vol 146 ◽  
pp. 491-502 ◽  
Author(s):  
Ulises A. Méndez-Romero ◽  
Sergio A. Pérez-García ◽  
Xiaofeng Xu ◽  
Ergang Wang ◽  
Liliana Licea-Jiménez
Keyword(s):  
Graphene Oxide ◽  
Band Gap ◽  
Reduced Graphene Oxide ◽  
Organic Solvents ◽  
Good Solubility ◽  
Reduced Graphene ◽  
Tunable Band Gap

scholarly journals XRD-HTA, UV Visible, FTIR and SEM Interpretation of Reduced Graphene Oxide Synthesized from High Purity Vein Graphite

2017 ◽  
Vol 14 (1) ◽  
pp. 19-30 ◽  
Author(s):  
C. H Manoratne ◽  
S. R. D. Rosa ◽  
I. R. M. Kottegoda
Keyword(s):  
Particle Size ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Reduction Process ◽  
Bet Surface Area ◽  
High Quality ◽  
Graphene Layers ◽  
Reduced Graphene ◽  
Uv Visible ◽  
Vein Graphite

Attempts were made to synthesize high quality graphite oxide (GO) and reduced graphene oxide (rGO) by using successive oxidation-reduction process of high quality vein graphite from Sri Lanka. We report the lowest optimum reduction temperature for converting GO to rGO which has been systematically studied using X-ray diffraction spectroscope (XRD) with the high temperature heating attachment (HTA) for the first time. The effect of particle size of graphite on properties of GO and rGO is also compared using commercially available graphite of particle size of ~111 mm and ball-milled graphite of particle size ~37 mm. The GO and rGO were characterized using XRD, UV-Visible spectroscopy, Fourier Transform Infrared spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). The GO and rGO synthesized from ball-milled graphite showed higher oxidation and reduction properties as verified through the UV-Vis and FTIR analysis. The SEM analysis revealed that the splitting of graphene layers is efficiently taken place in GO from ball-milled graphite. The lowest optimum temperature for thermal reduction of GO to rGO was found to be at 475 °C. FTIR confirmed the removal of most of the functional groups in rGO and according to the BET surface area analysis few layers, supposed to be 2-6 is formed. The efficient oxidation and reduction process of smaller particle size graphite has led to yield highly oxidized GO and high quality rGO which can be used to prepare high quality graphene for future applications.

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