Synthesis of white light emitting mesoporous carbon-silica nanocomposite

Sato, Kōji; Ishikawa, Yukari; Matsumura, Akihiro; Ishii, Yosuke; Kawasaki, Shigeo

doi:10.1088/1757-899x/18/10/102022

Cited by 7 publications

(8 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…All of these materials usually contain unpaired electrons, which serve as a basis for EPR investigations. The carbon-related paramagnetic centers have been studied also in carbosils [ 14 ] and SiO 2 :C based composites like oxidized mesoporous carbon-silica nanocomposite [ 15 ], carbon-silica sol-gel prepared nanopowders [ 16 ] and carbogenic nanodots [ 17 ].…”

Section: Introductionmentioning

confidence: 99%

Infrared, Raman and Magnetic Resonance Spectroscopic Study of SiO2:C Nanopowders

et al. 2017

View full text Add to dashboard Cite

Optical and magnetic properties of SiO2:C nanopowders obtained by chemical and thermal modification of fumed silica were studied by Fourier transform infrared spectroscopy, Raman, continuous wave (CW) electron paramagnetic resonance (EPR), echo-detected EPR and pulsed electron nuclear double resonance (ENDOR) spectroscopy. Two overlapping signals of Lorentzian lineshape were detected in CW EPR spectra of the initial SiO2:C. The EPR signal at g = 2.0055(3) is due to the silicon dangling bonds, which vanishes after thermal annealing, and the second EPR signal at g = 2.0033(3) was attributed to the carbon-related defect (CRD). The annealing of the SiO2:C samples gives rise to the increase of the CRD spin density and shift to the higher g-values due to the appearance of the oxygen in the vicinity of the CRD. Based on the temperature-dependent behavior of the CRD EPR signal intensity, linewidth and resonance field position we have attributed it to the spin system with non-localized electrons hopping between neighboring carbon dangling bonds, which undergo a strong exchange interaction with a localized spin system of carbon nanodots. The observed motional narrowing of the CRD EPR signal in the temperature interval from 4 to 20 K indicates that electrons are mobile at 4 K which can be explained by a quantum character of the conductivity in the vicinity of the carbon layer. The electrons trapped in quantum wells move from one carbon nanodot to another by hopping process through the energy barrier. The fact that echo-detected EPR signal at g = 2.0035(3) was observed in SiO2:C sample annealed at T ann ≥ 700 °C serves as evidence that non-localized electrons coexist with localized electrons that have the superhyperfine interaction with surrounding 13C and 29Si nuclei located at the SiO2:C interface. The presence of the superhyperfine interaction of CRD with 1H nuclei indicates the existence of hydrogenated regions in SiO2:C sample.

show abstract

Section: Introductionmentioning

confidence: 99%

Infrared, Raman and Magnetic Resonance Spectroscopic Study of SiO2:C Nanopowders

et al. 2017

View full text Add to dashboard Cite

show abstract

“…Moreover, the diffraction pattern measured by SAXS indicates that the sample has an 11 nm periodic structure. [13][14][15][16] A high magnification image of oxidized MPCS-0.2 M taken by highangle annular dark-field scanning TEM (HAADF-STEM) is shown in Fig. 2(b).…”

Section: Microstructurementioning

confidence: 99%

“…12,14) The PL intensity of SiOC seems to increase with surface area, as suggested by some reports that PL origins might be at the interface between carbon and silica. 12,14) Recently, we have found that mesoporous carbon-silica (MPCS) 13,15,16) that has a large surface area emits a strong white PL. In our previous studies, we found that PL intensity depends on hydrolysis and polycondensation reactions in the sol-gel method for preparing MPCS.…”

Section: Introductionmentioning

confidence: 99%

Effects of Synthesis Process on Luminescence Properties and Structure of Mesoporous Carbon–Silica Nanocomposite

Sato

Ishikawa

Ishii

et al. 2012

Jpn. J. Appl. Phys.

Self Cite

View full text Add to dashboard Cite

The effects of hydrolysis and polycondensation reactions for synthesizing light-emitting mesoporous carbon-silica (MPCS) nanocomposite on the structure, chemical bonding state, and luminescence properties of MPCS were investigated by controlling the concentration (0.02 to 5 M) of HCl, which was used as a catalyst for hydrolysis and polycondensation. The progress of hydrolysis and polycondensation reactions provides a nanometer-order pore/wall structure and results in a strong light-emitting property. The pore/wall structure was obtained using HCl at concentrations of 0.2 M and higher, but it became disordered with increasing HCl concentration (2 and 5 M). The luminescence color of the MPCS nanocomposite can be changed from yellowish-white to bluish-white by changing the concentration of HCl.

show abstract

“…Amorphous silicon‐oxycarbide materials have attracted attention due to their white photoluminescence (PL) property at room temperature (RT) 1–10. The silicon‐oxycarbide is expected to be a sustainable fluorescence material, because it is mainly composed of silicon, carbon, and oxygen and contains no rare‐earth elements.…”

Section: Introductionmentioning

confidence: 99%

“…The suggestion means that the PL intensity increases with the area of the interface of carbon cluster and silica. Therefore, we selected mesoporous carbon silica (MPCS) and rice husk as the starting materials for fabricating the light‐emitting amorphous silicon‐oxycarbide materials since they have large surface area coming from pore/wall structure 8–11. However, the PL origins have been unclear and there is no road map to control PL from silicon‐oxycarbide.…”

Section: Introductionmentioning

confidence: 99%

White light emission from amorphous silicon‐oxycarbide materials

Ishikawa

Sato

Kawasaki

et al. 2012

Physica Status Solidi (a)

Self Cite

View full text Add to dashboard Cite

This paper reports white photoluminescence (PL) from siliconoxycarbide materials. These are oxidized mesoporous carbon silica (MPCS) and thermally treated rice husk. The PL intensities were strong enough to be detected by the naked eye in daylight under ultraviolet light excitation at room temperature. We investigated the structure, composition, and bonding state of fabricated silicon-oxycarbide materials and found the commonality between the oxidized MPCS and the thermally treated rice husk. Both of them (i) were composed of silica and small amount of carbon, (ii) have porous structure and large surface area over 100 m 2 /g, and (iii) have a broad infrared absorption band at around 1100 cm À1 related to the strained silica. The origins of white PL are discussed by taking account of the commonality.

show abstract

Synthesis of white light emitting mesoporous carbon-silica nanocomposite

Cited by 7 publications

References 7 publications

Infrared, Raman and Magnetic Resonance Spectroscopic Study of SiO2:C Nanopowders

Infrared, Raman and Magnetic Resonance Spectroscopic Study of SiO2:C Nanopowders

Effects of Synthesis Process on Luminescence Properties and Structure of Mesoporous Carbon–Silica Nanocomposite

White light emission from amorphous silicon‐oxycarbide materials

Contact Info

Product

Resources

About