Tuning the sub-processes in laser reduction of graphene oxide by adjusting the power and scanning speed of laser

Zhang, Wan; Wang, Shu Jun; Haylock, Ben; Kaur, Jasreet; Tanner, Philip; Thiel, David V.; Sang, R. T.; Cole, Ivan; Li, Xiangping; Lobino, Mirko; Li, Qin

doi:10.1016/j.carbon.2018.09.030

Cited by 84 publications

(71 citation statements)

References 76 publications

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“…In single-layer pristine graphene, the ratio I2D/IG is ~2-3, and it decreases as the number of layers increase [47]. On this basis, the results of the rGO sheets showed that the rGO produced with the CO2 laser presents a lower number of layers (higher I2D/IG ratio) than the one induced with the UV laser, which might be related to its lower thickness (~12 μm, in comparison with ~18 μm, according to profilometry results) due to the higher irradiation power, as demonstrated in other works [48]. In addition, the lower FWHM2D also indicates that these layers have a better crystallographic structure [49].…”

Section: Resultssupporting

confidence: 65%

Comparison of Laser-Synthetized Nanographene-Based Electrodes for Flexible Supercapacitors

et al. 2020

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In this paper, we present a comparative study of a cost-effective method for the mass fabrication of electrodes to be used in thin-film flexible supercapacitors. This technique is based on the laser-synthesis of graphene-based nanomaterials, specifically, laser-induced graphene and reduced graphene oxide. The synthesis of these materials was performed using two different lasers: a CO2 laser with an infrared wavelength of λ = 10.6 µm and a UV laser (λ = 405 nm). After the optimization of the parameters of both lasers for this purpose, the performance of these materials as bare electrodes for flexible supercapacitors was studied in a comparative way. The experiments showed that the electrodes synthetized with the low-cost UV laser compete well in terms of specific capacitance with those obtained with the CO2 laser, while the best performance is provided by the rGO electrodes fabricated with the CO2 laser. It has also been demonstrated that the degree of reduction achieved with the UV laser for the rGO patterns was not enough to provide a good interaction electrode-electrolyte. Finally, we proved that the specific capacitance achieved with the presented supercapacitors can be improved by modifying the in-planar structure, without compromising their performance, which, together with their compatibility with doping-techniques and surface treatments processes, shows the potential of this technology for the fabrication of future high-performance and inexpensive flexible supercapacitors.

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Section: Resultssupporting

confidence: 65%

Comparison of Laser-Synthetized Nanographene-Based Electrodes for Flexible Supercapacitors

et al. 2020

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“…The laser is only used for the fabrication of the samples and it is not involved in the electrical measurements carried out for the characterization of the resistive switching of the devices. Starting with the bare GO film, the laser triggers a photothermal reduction process that removes oxygen-containing functional groups (increasing the atomic percentage of carbon) and partially recovers the sp 2 hybridized carbon-carbon bonds, increasing the conductivity of the nanographene flakes according to the laser power [28]. The laser power can be adjusted to modulate the conductivity of the samples leading to different levels of reduction.…”

Section: Methodsmentioning

confidence: 99%

“…The laser-scribing process was performed at room temperature with a controlled relative humidity of 50% and a constant airflow forced by a fume extractor system. These conditions avoid any intentional doping during the lithographic process; however, the intentional doping/functionalization of the devices by setting an appropriate environment during the laser-scribing process [28,29] constitutes a path to be explored for boosting the performance of this type of devices. Micro drops of bare conductive electric paint TM or Ag-based conductive paint were placed as electrodes to define the electrical access and to avoid any damage on the active GO material when contacting the devices with probes.…”

Section: Methodsmentioning

confidence: 99%

Laser-Fabricated Reduced Graphene Oxide Memristors

et al. 2019

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Finding an inexpensive and scalable method for the mass production of memristors will be one of the key aspects for their implementation in end-user computing applications. Herein, we report pioneering research on the fabrication of laser-lithographed graphene oxide memristors. The devices have been surface-fabricated through a graphene oxide coating on a polyethylene terephthalate substrate followed by a localized laser-assisted photo-thermal partial reduction. When the laser fluence is appropriately tuned during the fabrication process, the devices present a characteristic pinched closed-loop in the current-voltage relation revealing the unique fingerprint of the memristive hysteresis. Combined structural and electrical experiments have been conducted to characterize the raw material and the devices that aim to establish a path for optimization. Electrical measurements have demonstrated a clear distinction between the resistive states, as well as stable memory performance, indicating the potential of laser-fabricated graphene oxide memristors in resistive switching applications.

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“…The chemical alterations induced by the laser photothermal process were also studied by XPS. As was expected, the laser reduction led to a dramatic change in the original carbon–oxygen compounds of the GO layer [28,29]. Thus, the initial carbon atomic content of ~52% increased up to 90% after the laser reduction process, whereas the oxygen presented a decrease from ~45% before the photothermal process to ~6% after, meaning an increase from ~1 to ~15 of the atomic carbon to oxygen ratio (C/O).…”

Section: Resultsmentioning

confidence: 71%

Inexpensive Graphene Oxide Heaters Lithographed by Laser

et al. 2019

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In this paper, we present a simple and inexpensive method for the fabrication of high-performance graphene-based heaters on different large-scale substrates through the laser photothermal reduction of graphene oxide (laser-reduced graphene-oxide, LrGO). This method allows an efficient and localized high level of reduction and therefore a good electrical conductivity of the treated films. The performance of the heaters is studied in terms of steady-state temperature, power consumption, and time response for different substrates and sizes. The results show that the LrGO heaters can achieve stable steady-state temperatures higher than 200 °C when a voltage of 15 V is applied, featuring a time constant of around 4 s and a heat transfer coefficient of ~200 °C cm2/W. These characteristics are compared with other technologies in this field, demonstrating that the fabrication approach described in this work is competitive and promising to fabricate large-scale flexible heaters with a very fast response and high steady-state temperatures in a cost-effective way. This technology can be easily combined with other fabrication methods, such as screen printing or spray-deposition, for the manufacturing of complete sensing systems where the temperature control is required to adjust functionalities or to tune sensitivity or selectivity.

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Tuning the sub-processes in laser reduction of graphene oxide by adjusting the power and scanning speed of laser

Cited by 84 publications

References 76 publications

Comparison of Laser-Synthetized Nanographene-Based Electrodes for Flexible Supercapacitors

Comparison of Laser-Synthetized Nanographene-Based Electrodes for Flexible Supercapacitors

Laser-Fabricated Reduced Graphene Oxide Memristors

Inexpensive Graphene Oxide Heaters Lithographed by Laser

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