Limits...
Synthesis of diamond-like phase from graphite by ultrafast laser driven dynamical compression.

Maia FC, Samad RE, Bettini J, Freitas RO, Vieira Junior ND, Souza-Neto NM - Sci Rep (2015)

Bottom Line: Here, by exposing polycrystalline graphite to 25 fs laser pulses at 4 J/cm(2) fluence under standard air atmosphere, we demonstrated the synthesis of translucent micrometer-sized structures carrying diamond-like and onion-like carbon phases.Texturized domains of the diamond phase were also identified.Concerning different synthesized carbon forms, pulse superposition and singularities of the thermodynamical process, we pinpoint the synthesis mechanism by the laser-induced subsequent products energetically evolving to attain the diamond-like phase.

View Article: PubMed Central - PubMed

Affiliation: Laboratório Nacional de Luz Síncrotron (LNLS), Campinas, São Paulo 13083-970, Brazil.

ABSTRACT
Rapid variations of the environmental energy caused by ultrashort laser pulses have induced phase transitions in carbon allotropes, therefore bringing the promise of revealing new carbon phases. Here, by exposing polycrystalline graphite to 25 fs laser pulses at 4 J/cm(2) fluence under standard air atmosphere, we demonstrated the synthesis of translucent micrometer-sized structures carrying diamond-like and onion-like carbon phases. Texturized domains of the diamond phase were also identified. Concerning different synthesized carbon forms, pulse superposition and singularities of the thermodynamical process, we pinpoint the synthesis mechanism by the laser-induced subsequent products energetically evolving to attain the diamond-like phase.

No MeSH data available.


Related in: MedlinePlus

On the left are shown the Raman spectra and on the right the respective SEM images.(a) and (b) refer to the polycrystalline graphite (precursor). (c) and (d) correspond to the laser-modified surface, and in (c), the thicker red curve is the measured Raman spectrum and the gray ones are its component bands obtained from Voigt functions fittings. (e) and (f) present the measurements for the laser-created structure (the corresponding optical image is shown in the Figure S1 of the Supplementary Information, which also shows the Raman spectra for two other laser created particles). Clear morphological differences are noted between the precursor and the laser modified materials. The raw graphite contains disordered and buckled flakes (b). In (d) the material features micrometer sized globular formations composed by nanometer sized structures. Stacked layers resulting from shockwaves dynamic compressed carbon produce the structure shown in (e).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4493556&req=5

f1: On the left are shown the Raman spectra and on the right the respective SEM images.(a) and (b) refer to the polycrystalline graphite (precursor). (c) and (d) correspond to the laser-modified surface, and in (c), the thicker red curve is the measured Raman spectrum and the gray ones are its component bands obtained from Voigt functions fittings. (e) and (f) present the measurements for the laser-created structure (the corresponding optical image is shown in the Figure S1 of the Supplementary Information, which also shows the Raman spectra for two other laser created particles). Clear morphological differences are noted between the precursor and the laser modified materials. The raw graphite contains disordered and buckled flakes (b). In (d) the material features micrometer sized globular formations composed by nanometer sized structures. Stacked layers resulting from shockwaves dynamic compressed carbon produce the structure shown in (e).

Mentions: The Raman spectra and the SEM micrographs shown in Fig. 1 present the evolution of the induced modifications in the ultrashort laser pulses irradiated polycrystalline graphite sample through assessing the stages from the precursor (Fig. 1a,b), the intermediary stage found at the irradiated surface (Fig. 1c,d), to the final diamond-like structure (Fig. 1e,f).


Synthesis of diamond-like phase from graphite by ultrafast laser driven dynamical compression.

Maia FC, Samad RE, Bettini J, Freitas RO, Vieira Junior ND, Souza-Neto NM - Sci Rep (2015)

On the left are shown the Raman spectra and on the right the respective SEM images.(a) and (b) refer to the polycrystalline graphite (precursor). (c) and (d) correspond to the laser-modified surface, and in (c), the thicker red curve is the measured Raman spectrum and the gray ones are its component bands obtained from Voigt functions fittings. (e) and (f) present the measurements for the laser-created structure (the corresponding optical image is shown in the Figure S1 of the Supplementary Information, which also shows the Raman spectra for two other laser created particles). Clear morphological differences are noted between the precursor and the laser modified materials. The raw graphite contains disordered and buckled flakes (b). In (d) the material features micrometer sized globular formations composed by nanometer sized structures. Stacked layers resulting from shockwaves dynamic compressed carbon produce the structure shown in (e).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4493556&req=5

f1: On the left are shown the Raman spectra and on the right the respective SEM images.(a) and (b) refer to the polycrystalline graphite (precursor). (c) and (d) correspond to the laser-modified surface, and in (c), the thicker red curve is the measured Raman spectrum and the gray ones are its component bands obtained from Voigt functions fittings. (e) and (f) present the measurements for the laser-created structure (the corresponding optical image is shown in the Figure S1 of the Supplementary Information, which also shows the Raman spectra for two other laser created particles). Clear morphological differences are noted between the precursor and the laser modified materials. The raw graphite contains disordered and buckled flakes (b). In (d) the material features micrometer sized globular formations composed by nanometer sized structures. Stacked layers resulting from shockwaves dynamic compressed carbon produce the structure shown in (e).
Mentions: The Raman spectra and the SEM micrographs shown in Fig. 1 present the evolution of the induced modifications in the ultrashort laser pulses irradiated polycrystalline graphite sample through assessing the stages from the precursor (Fig. 1a,b), the intermediary stage found at the irradiated surface (Fig. 1c,d), to the final diamond-like structure (Fig. 1e,f).

Bottom Line: Here, by exposing polycrystalline graphite to 25 fs laser pulses at 4 J/cm(2) fluence under standard air atmosphere, we demonstrated the synthesis of translucent micrometer-sized structures carrying diamond-like and onion-like carbon phases.Texturized domains of the diamond phase were also identified.Concerning different synthesized carbon forms, pulse superposition and singularities of the thermodynamical process, we pinpoint the synthesis mechanism by the laser-induced subsequent products energetically evolving to attain the diamond-like phase.

View Article: PubMed Central - PubMed

Affiliation: Laboratório Nacional de Luz Síncrotron (LNLS), Campinas, São Paulo 13083-970, Brazil.

ABSTRACT
Rapid variations of the environmental energy caused by ultrashort laser pulses have induced phase transitions in carbon allotropes, therefore bringing the promise of revealing new carbon phases. Here, by exposing polycrystalline graphite to 25 fs laser pulses at 4 J/cm(2) fluence under standard air atmosphere, we demonstrated the synthesis of translucent micrometer-sized structures carrying diamond-like and onion-like carbon phases. Texturized domains of the diamond phase were also identified. Concerning different synthesized carbon forms, pulse superposition and singularities of the thermodynamical process, we pinpoint the synthesis mechanism by the laser-induced subsequent products energetically evolving to attain the diamond-like phase.

No MeSH data available.


Related in: MedlinePlus