Photoreduction of graphite oxide at different temperatures

Смирнов, В. А.; Shul’ga, Yu. M.; Денисов, Н. Н.; Kresova, E. I.; Shul’ga, N. Yu.

doi:10.1134/s1995078012020164

Cited by 20 publications

(13 citation statements)

References 28 publications

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“…Associated activation energies are 0.7 eV for OH [59], 1.9-2.1 eV for C-O-C [59,62], and 3-4 eV for C=O and COOH groups [25,58,60]. Additional, more complicated, light-induced chemistries are also possible wherein multiple functional groups (primarily hydroxyls) interact to evolve H 2 O (E a~0 .28-0.46 eV) [61].…”

Section: Go Photolysismentioning

confidence: 96%

Spectroscopy and Microscopy of Graphene Oxide and Reduced Graphene Oxide

et al. 2015

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Graphene oxide (GO) is an important material that provides a scalable approach for obtaining chemically derived graphene. Its optical and electrical properties are largely determined by the presence of oxygen-containing functionalities, which decorate its basal plane. This chemical derivatization results in useful properties such as the existence of a band gap as well as emission spanning both the visible and near infrared. Notably, GO's optical and electrical properties can be altered through reduction, which proceeds through the removal of these oxygen-containing functional groups. However, widely variable behavior has been observed regarding the evolution of GO's optical response during reduction. These discrepancies arise from the different reduction methods being used and, in part, from the fact that nearly all prior measurements have been ensemble studies. Consequently, detailed mechanistic studies of GO reduction are needed which can transcend the limitations of ensemble averaging.In this chapter, we show the spectroscopic evolution of GO's optical properties during photoreduction at the single-sheet level. Laser-induced reduction, in particular, offers a unique and potentially controllable method for producing reduced GO (rGO), a material with properties similar to those of graphene. However, given the complexity of GO's photoreduction mechanism, microscopic monitoring of the process is essential to understanding and ultimately exploiting this approach.

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Section: Go Photolysismentioning

confidence: 96%

Spectroscopy and Microscopy of Graphene Oxide and Reduced Graphene Oxide

et al. 2015

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“…The threshold for GO reduction dominated by photochemical reduction mechanism requires photon energy greater than 3.2 ev (λ < 390 nm) and conversely, the photothermal reduction mechanism dominates when the wavelength is larger than 390 nm. [33][34][35] As illustrated by Figure 1a,b, the photochemical reduction of GO is induced by a UV light at a wavelength of 275 nm, [14,28,29] and the photothermal reduction of GO is induced by a CW laser at a wavelength of 808 nm. The Raman spectra of rGO show two peaks around 1359 and 1602 cm -1 after photoreduction, which correspond to the D and G bands, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…While the photothermal reduction is due to lattice vibrations, which leads to the formation of more small π fields in the photothermal regime. [30][31][32][33][34][35][36][37] In order to explore the corresponding distinctions of nonlinear optical response, after the photochemical reduction and photothermal reduction, we characterized the nonlinear optical response of rGO via Z-scan method using a femtosecond laser at a wavelength of 800 nm as a probe beam. The details of the Z-scan setup for measuring the nonlinear coefficients of GO thin film are shown in section Z-scan system setup and Figure S1, Supporting Information.…”

Section: Resultsmentioning

confidence: 99%

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Giant Nonlinear Optical Response of Graphene Oxide Thin Films Under the Photochemical and Photothermal Reduction

Wang

Hao

et al. 2022

Adv Materials Inter

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Thin graphene oxide (GO) films have been widely explored for their outstanding optical properties, especially their large optical nonlinear coefficients, and high tunability of optical nonlinear coefficients under photoreduction. In this work, an experimental observation of giant nonlinear optical response in GO films under two different photoreduction mechanisms is reported. After ultraviolet (UV) light‐induced photochemical reduction and continuous wave (CW) laser‐induced photothermal reduction, the nonlinear optical response of reduced graphene oxide (rGO) via the Z‐scan method using a femtosecond laser beam at a wavelength of 800 nm is characterized. The rGO exhibits a giant optical nonlinearity, especially two‐photon absorption (TPA). A giant TPA coefficient of rGO on the order of ≈105 cm GW−1 is obtained under two photoreduction mechanisms (photochemistry and photothermal). This is the first time that a large enhancement effect of TPA has been observed in graphene‐based materials, and the TPA coefficient is an order of magnitude higher than the highest value previously reported. The versatile optical nonlinear properties imply a huge potential of the GO film in advanced photonic and optoelectronic devices such as broadband ultrafast optical switching and optical limiting.

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“…It may be noted that all other peaks showed decreased intensity compared with before irradiation. The mechanism of GO's photochemical reduction under UV laser irradiation thus comprised the elimination of oxygen groups through the dissociation of bonds from electronically excited states, which can be explained through photochemical processes in polyatomic aromatic molecules (Figure c) …”

mentioning

confidence: 99%

Millisecond‐Timescale, High‐Efficiency Modulation of Upconversion Luminescence by Photochemically Derived Graphene

Lamon

Zhang

et al. 2019

Advanced Optical Materials

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The millisecond‐timescale, high‐efficiency modulation of upconversion luminescence via ultraviolet laser‐induced photochemical reduction of graphene oxide is reported. The luminescence tuning is achieved by combining a thin film of graphene oxide with lanthanide‐doped upconversion nanoparticles. The recovery of the graphene‐like structure through the photochemical reduction of graphene oxide is accompanied by a variation in the absorption coefficient of the as‐synthesized nanocomposite, which enables super‐quenching of the luminescence emission from the upconversion nanoparticles under near‐infrared laser excitation with values of up to ≈90%. Further, the instantaneous reduction in the emission intensity upon ultraviolet laser irradiation allows a 106‐fold decrease of the time for fast modulation of upconversion luminescence from up to tens of minutes down to milliseconds at microwatt‐level laser power. Optical patterning is successfully produced in the nanocomposite and individual pixels are retrieved distinctly with high spatial resolution through upconversion luminescence emission quenching by reduced graphene oxide. This method offers a superior avenue for controlling upconversion luminescence with high contrast, fast reaction speed, and low power consumption.

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Photoreduction of graphite oxide at different temperatures

Cited by 20 publications

References 28 publications

Spectroscopy and Microscopy of Graphene Oxide and Reduced Graphene Oxide

Spectroscopy and Microscopy of Graphene Oxide and Reduced Graphene Oxide

Giant Nonlinear Optical Response of Graphene Oxide Thin Films Under the Photochemical and Photothermal Reduction

Millisecond‐Timescale, High‐Efficiency Modulation of Upconversion Luminescence by Photochemically Derived Graphene

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