scholarly journals Analysis of energy gap opening in graphene oxide

2014 ◽  
Vol 526 ◽  
pp. 012003 ◽  
Author(s):  
Mark Lundie ◽  
Željko Šljivančanin ◽  
Stanko Tomić
Keyword(s):  
Graphene Oxide ◽  
Energy Gap ◽  
Gap Opening

Local Energy Gap Opening Induced by Hemin Dimerization in Aqueous Solution

2015 ◽  
Vol 119 (7) ◽  
pp. 3058-3062 ◽  
Author(s):  
Ronny Golnak ◽  
Jie Xiao ◽  
Kaan Atak ◽  
Munirah Khan ◽  
Edlira Suljoti ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Energy Gap ◽  
Local Energy ◽  
Gap Opening

Energy gap opening by crossing drop cast single-layer graphene nanoribbons

2018 ◽  
Vol 29 (31) ◽  
pp. 315705 ◽  
Author(s):  
Toyo Kazu Yamada ◽  
Hideto Fukuda ◽  
Taizo Fujiwara ◽  
Polin Liu ◽  
Kohji Nakamura ◽  
...  
Keyword(s):  
Energy Gap ◽  
Graphene Nanoribbons ◽  
Single Layer ◽  
Single Layer Graphene ◽  
Layer Graphene ◽  
Gap Opening

Enhancing the Power Conversion Efficiency of Inverted Organic Photovoltaics with Gold Functionalized Reduced Graphene Oxide

2015 ◽  
Vol 1737 ◽  
Author(s):  
Rebecca Isseroff ◽  
Zhenhua Yang ◽  
Jessica Kim ◽  
Andrew Chen ◽  
Miriam Rafailovich
Keyword(s):  
Graphene Oxide ◽  
Fermi Level ◽  
Reduced Graphene Oxide ◽  
Active Layer ◽  
Energy Gap ◽  
Power Conversion ◽  
Design Phase ◽  
Reduced Graphene ◽  
Exciton Recombination ◽  
First Time

ABSTRACTIn this study, an “inverted” design, phase-separated morphology and gold-functionalized reduced graphene oxide (Au-rGO) were used to address exciton recombination and poor Fermi level alignment. To increase efficiencies, a unique methodology was used to coat Au-rGO on top of the active layer. When 0.05 Au-rGO was blended with the active layer, there were metal-thiolate bonds with P3HT and π-π stacking with PCBM. However, KPFM, measured for the first time for this material, showed that the while 0.05mM Au-rGO reduced the energy gap between P3HT and PBCM, this was offset by recombination. KPFM showed that Au-rGO may be better suited between the active layer and electrode. When 0.5mM Au-rGO was coated on top of the active layer, efficiency increased (p<0.002) nearly 600%, suggesting that Au-rGO is a more effective acceptor than a constituent of the active layer.

scholarly journals Evidence for a vestigial nematic state in the cuprate pseudogap phase

2019 ◽  
Vol 116 (27) ◽  
pp. 13249-13254 ◽  
Author(s):  
Sourin Mukhopadhyay ◽  
Rahul Sharma ◽  
Chung Koo Kim ◽  
Stephen D. Edkins ◽  
Mohammad H. Hamidian ◽  
...  
Keyword(s):  
Fermi Surface ◽  
Energy Gap ◽  
Density Wave ◽  
Broken Symmetry ◽  
Hole Doping ◽  
Thermal Transitions ◽  
Electronic Density ◽  
Pseudogap Phase ◽  
Nematic State ◽  
Gap Opening

The CuO2 antiferromagnetic insulator is transformed by hole-doping into an exotic quantum fluid usually referred to as the pseudogap (PG) phase. Its defining characteristic is a strong suppression of the electronic density-of-states D(E) for energies |E| < Δ*, where Δ* is the PG energy. Unanticipated broken-symmetry phases have been detected by a wide variety of techniques in the PG regime, most significantly a finite-Q density-wave (DW) state and a Q = 0 nematic (NE) state. Sublattice-phase-resolved imaging of electronic structure allows the doping and energy dependence of these distinct broken-symmetry states to be visualized simultaneously. Using this approach, we show that even though their reported ordering temperatures TDW and TNE are unrelated to each other, both the DW and NE states always exhibit their maximum spectral intensity at the same energy, and using independent measurements that this is the PG energy Δ*. Moreover, no new energy-gap opening coincides with the appearance of the DW state (which should theoretically open an energy gap on the Fermi surface), while the observed PG opening coincides with the appearance of the NE state (which should theoretically be incapable of opening a Fermi-surface gap). We demonstrate how this perplexing phenomenology of thermal transitions and energy-gap opening at the breaking of two highly distinct symmetries may be understood as the natural consequence of a vestigial nematic state within the pseudogap phase of Bi2Sr2CaCu2O8.

scholarly journals Enhance the gas-sensing performances of graphene oxide (GO) thin films for detecting nitrogen dioxide gas

2021 ◽  
Vol 26 (4) ◽  
Author(s):  
Ali Al-jawdah ◽  
Rathyah Jarrah ◽  
Mohsin Al-Khaykanee ◽  
Mirjam Skof
Keyword(s):  
Thin Films ◽  
Graphene Oxide ◽  
Energy Gap ◽  
Gas Sensing ◽  
Operating Temperature ◽  
Temperature Response ◽  
Absorption Spectrometry ◽  
Optical Energy Gap ◽  
Gas Concentration ◽  
Sensor Applications

In this work, graphene oxide (GO) synthesized via a modified Hummer method was utilized to manufacture thin films for gas sensor applications. The films were prepared on glass substrates using the spin coating technique, the concentration of GO was varied in the precursor liquid. The crystall ographic properties of the prepared GO films were analyzed using XRD and the results showed a polycrystalline structure with a crystallite size of 15.51 nm. Using the weighing method, the average film thickness was determined to be about 200 nm. UV-Vis absorption spectrometry combined with the Tauc method confirmed the indirect nature (allowed and forbidden) of electronic transitions in the samples and it also showed a decrease in the optical energy gap with an increasing amount of GO in the samples. Values for Eg ranged from 2.4 eV to 2.15 eV for allowed transitions and from 3.05 eV to 2.6 eV for forbidden transitions. Gas sensing measurements were performed using NO2 as target gas at different operating temperatures (50, 100, 200 and 300 oC), as well as four target gas concentration (100 ppm, 400 ppm, 700 ppm, and 1000 ppm) have been tested and shows the good response in the range of 10%. It can be seen that the sensitivity increases with increasing operating temperature and gas concentration. At 300 oC operating temperature response and recovery time decrease to their lowest value or 2.6 and 5 seconds, respectively.

scholarly journals Band gap opening of bilayer graphene by graphene oxide support doping

RSC Advances ◽  
2017 ◽  
Vol 7 (16) ◽  
pp. 9862-9871 ◽  
Author(s):  
Shaobin Tang ◽  
Weihua Wu ◽  
Xiaojun Xie ◽  
Xiaokang Li ◽  
Junjing Gu
Keyword(s):  
Graphene Oxide ◽  
Band Gap ◽  
Bilayer Graphene ◽  
Monolayer Graphene ◽  
Graphene Oxides ◽  
Oxide Support ◽  
Gap Opening

In contrast to the metallic monolayer graphene by graphene oxides (GOs) doping, the sizable band gap of bilayer graphene is opened by GOs.

scholarly journals Energy-gap opening and quenching in graphene under periodic external potentials

2010 ◽  
Vol 133 (22) ◽  
pp. 224705 ◽  
Author(s):  
Aihua Zhang ◽  
Zhenxiang Dai ◽  
Lei Shi ◽  
Yuan Ping Feng ◽  
Chun Zhang
Keyword(s):  
Energy Gap ◽  
Gap Opening

Study on Phase, Molecular Bonding, and Bandgap of Reduced Graphene Oxide Prepared by Heating Coconut Shell

2015 ◽  
Vol 827 ◽  
pp. 285-289 ◽  
Author(s):  
Ananda Yogi Nugraheni ◽  
Muhammad Nasrullah ◽  
Fandi Angga Prasetya ◽  
Fahmi Astuti ◽  
Darminto
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Energy Gap ◽  
Heating Temperature ◽  
Ambient Air ◽  
Xrd Analysis ◽  
Coconut Shell ◽  
Gas Treatment ◽  
Reduced Graphene ◽  
Molecular Bonding

The purpose of this work is to search reduced graphene oxide (RGO) phase by identifying the molecular bonding, energy band gap and phase of old coconut shell. The characterization was performed by using FTIR, Uv-Vis and XRD spectroscopy. The heating temperature used in this work was 400°C and 600°C.Furthermore, the type of heating atmosphere used in this research covers nitrogen, ambient air with and without rinsing step. The XRD analysis shows that the RGO phase is formed by turbostatic structure which is a pile of random arrangement of parallel layers that make up the graphite structure with cliftonite phase at temperature 400°C and 600°C. In the inert nitrogen gas treatment, there are two impurity phases such as potassium chlorate (KClO4) and sulfur (S11). The molecular bondings of C=C, C-C, C-O, C=O, C-H and O-H appeared on the FTIR spectra of the samples were indentified. Analysis by using linear regression and absorbance edge methods was conducted to result in energy gap in the range from 0.14 to 0.67 eV, indicating that the produced samples are semiconducting materials.

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