Fumed silica with a specific area of 295 m2/g was carbonized by successive phenyltrimethoxysilane treatments followed by annealing in inert atmosphere up to 650 °C. Emission, excitation, kinetics, and photo-induced bleaching effects were investigated by steady state and time-resolved photoluminescence spectroscopies. The local chemistry was also studied by infrared transmission spectroscopy. Strong ultraviolet and visible photoluminescence was observed in the samples after the chemical treatments/modifications and thermal annealing. It has been shown that ultraviolet photoluminescence in chemically modified fumed silica is associated with phenyl groups, while near ultraviolet and visible emission in annealed samples originated from inorganic pyrolytic carbon precipitates dispersed in the silica host matrix. Two types of emission bands were identified as a function of the annealing temperature: one is in the near UV and the other is in the visible range. Based on the emission/excitation analysis of these two bands, as well as on correlations with the synthesis conditions, a structural-energy concept of light-emitting centers has been proposed. According to this model, the light-emitting centers are associated with carbon clusters that can be bonded or adsorbed on the silica surface. This has been validated by a detailed (S)TEM-electron energy-loss spectroscopy study, confirming the inhomogeneous distribution of nanoscale carbon precipitates at the surface of the silica nanoparticles. These carbon precipitates are mostly amorphous although they possess some degree of graphitization and local order. Finally, the fraction of sp2 carbon in these nanoclusters has been estimated to be close to 80%.

1.
A.
Edgar
, “
Luminescent materials
,” in
Springer Handbook of Electronic and Photonic Materials
, edited by
S.
Kasap
and
P.
Capper
(
Springer International Publishing AG
,
2017
), pp.
997
1012
.
2.
O. S.
Wolfbeis
, “
An overview of nanoparticles commonly used in fluorescent bioimaging
,”
Chem. Soc. Rev.
44
,
4743
4768
(
2015
).
3.
H.
Shen
,
H.
Wang
,
X.
Chen
,
J. Zh.
Niu
,
W.
Xu
,
X. M.
Li
,
X.-D.
Jiang
,
Z.
Du
, and
L. S.
Li
, “
Size- and shape-controlled synthesis of CdTe and PbTe nanocrystals using tellurium dioxide as the tellurium precursor
,”
Chem. Mater.
22
,
4756
4761
(
2010
).
4.
See http://ec.europa.eu/environment/waste/rohs_eee/index_en.htm for EU policy on Restriction of Hazardous Substances.
5.
P.
Mushonga
,
M. O.
Onani
,
A. M.
Madiehe
, and
M.
Meyer
, “
Indium phosphide-based semiconductor nanocrystals and their applications
,”
J. Nanomater.
2012
,
869284
.
6.
A.
Vasin
,
A.
Rusavsky
,
A.
Nazarov
,
V.
Lysenko
,
G.
Rudko
,
Y.
Piryatinski
,
I.
Blonsky
,
J.
Salonen
,
E.
Makila
, and
S.
Starik
, “
Excitation effects and luminescence stability in porous SiO2: C layers
,”
Phys. Status Solidi A
209
,
1015
1021
(
2012
).
7.
A. V.
Vasin
,
M.
Adlung
,
V. A.
Tertykh
,
D.
Kysil
,
S.
Gallis
,
A. N.
Nazarov
, and
V. S.
Lysenko
, “
Broad band (UV-VIS) photoluminescence from carbonized fumed silica: Emission, excitation and kinetic properties
,”
J. Lumin.
190
,
141
147
(
2017
).
8.
Y.
Ishii
,
A.
Matsumura
,
Y.
Ishikawa
, and
S.
Kawasaki
, “
White light emission from mesoporous carbon–silica nanocomposites
,”
Jpn. J. Appl. Phys.
50
,
01AF06
(
2011
).
9.
F.
Fabbri
,
F.
Rossi
,
M.
Negri
,
R.
Tatti
,
L.
Aversa
,
S. Ch.
Dhanabalan
,
R.
Verucchi
,
G.
Attolini
, and
G.
Salviati
, “
Carbon doped SiOx nanowire with a large yield of white emission
,”
Nanotechnology
25
,
185704
(
2014
).
10.
N.
Tabassum
,
V.
Nikas
,
B.
Ford
,
M.
Huang
,
A. E.
Kaloyeros
, and
S.
Gallis
, “
Time-resolved analysis of the white photoluminescence from chemically synthesized SiCxOy thin films and nanowires
,”
Appl. Phys. Let.
109
,
043104
(
2016
).
11.
Q.
Wang
,
W.
Zhang
,
M.
Zhong
,
J.
Ma
,
Z.
Wu
, and
G.
Wang
, “
Synthesis and photoluminescence of amorphous silicon oxycarbide nanowires
,”
Chin. J. Chem. Phys.
28
,
184
190
(
2015
).
12.
G.
Mera
,
I.
Menapace
,
S.
Widgeon
,
S.
Sen
, and
R.
Riedel
, “
Photoluminescence of as-synthesized and heat-treated phenyl-containing polysilylcarbodiimides: Role of crosslinking and free carbon formation in polymer-derived ceramics
,”
Appl. Organomet. Chem.
27
,
630
638
(
2013
).
13.
P.
Roy
,
P.-C.
Chen
,
A. P.
Periasamy
,
Y.-N.
Chen
, and
H.-T.
Chang
, “
Photoluminescent carbon nanodots: Synthesis, physicochemical properties and analytical applications
,”
Mater. Today
18
,
447
458
(
2015
).
14.
S.
Zhu
,
Y.
Song
,
X.
Zhao
,
J.
Shao
,
J.
Zhang
, and
B.
Yang
, “
The photoluminescence mechanism in carbondots (graphene quantum dots, carbon nanodots, and polymer dots): Current state and future perspective
,”
Nano Res.
8
,
355
381
(
2015
).
15.
L.
Lajaunie
,
C.
Pardanaud
,
C.
Martin
,
P.
Puech
,
C.
Hu
,
M. J.
Biggs
, and
R.
Arenal
, “
Advanced spectroscopic analyses on a: CH materials: Revisiting the EELS characterization and its coupling with multi-wavelength Raman spectroscopy
,”
Carbon
112
,
149
161
(
2017
).
16.
K.
Gross
,
J. P.
Barragán
,
S.
Sangiao
,
J. M.
De Teresa
,
L.
Lajaunie
,
R.
Arenal
, and
P.
Prieto
, “
Electrical conductivity of oxidized-graphenic nanoplatelets obtained from bamboo: Effect of the oxygen content
,”
Nanotechnology
27
,
365708
(
2016
).
17.
M. L.
Miller
and
R. W.
Linton
, “
X-ray photoelectron spectroscopy of thermally treated silica (SiO2) surfaces
,”
Anal. Chem.
57
,
2314
2319
(
1985
).
18.
G. D.
Sorarú
,
G.
D'Andrea
, and
A.
Glisenti
, “
XPS characterization of gel-derived silicon oxycarbide glasses
,”
Mater. Lett.
27
,
l
5
(
1996
).
19.
D.
Yang
,
A.
Velamakanni
,
G.
Bozoklu
,
S.
Park
,
M.
Stoller
,
R. D.
Piner
, and
R. S.
Ruoff
, “
Chemical analysis of graphene oxide films after heat and chemical treatments by X-ray photoelectron and micro-Raman spectroscopy
,”
Carbon
47
(
1
),
145
152
(
2009
).
20.
R.
Rozada
,
J. I.
Paredes
,
S.
Villar-Rodil
,
A.
Martínez-Alonso
, and
J. M.
Tascón
, “
Towards full repair of defects in reduced graphene oxide films by two-step graphitization
,”
Nano Res.
6
(
3
),
216
233
(
2013
).
21.
G. S.
Chen
,
C. B.
Boothroyd
, and
C. J.
Humphreys
, “
Novel fabrication method for nanometer‐scale silicon dots and wires
,”
Appl. Phys. Lett.
62
,
1949
1951
(
1993
).
22.
L. A.
Garvie
and
P. R.
Buseck
, “
Bonding in silicates: Investigation of the Si L2, 3 edge by parallel electron energy-loss spectroscopy
,”
Am. Miner.
84
,
946
964
(
1999
).
23.
M. C.
Ortega-Liebana
,
J. L.
Hueso
,
R.
Arenal
,
R.
Lahoz
,
G. F.
de la Fuente
, and
J.
Santamaría
, “
Continuous-mode laser ablation at the solid−liquid interface of pelletized low-cost materials for the production of luminescent silicon carbide nanocrystals
,”
J. Phys. Chem. C
119
,
2158
2165
(
2015
).
24.
R. F. S.
Lenza
and
W. L.
Vaskoncelos
, “
Preparation of silica by sol-gel method using formamide
,”
Mater. Res.
4
,
189
196
(
2001
).
25.
B.
Stuart
,
Infrared Spectroscopy: Fundamentals and Applications
(
John Wiley & Sons, Ltd.
,
2004
).
26.
I. S.
Ignatyev b
,
M.
Montejo
,
F.
Partal Ureña
,
T.
Sundius
, and
J. J.
López González
, “
Vibrational spectra and structure of methoxysilanes and products of their hydrolysis
,”
Vib. Spectrosc.
40
,
1
12
(
2006
).
27.
D.
Savchenko
,
V.
Vorliček
,
E.
Kalabukhova
,
A.
Sitnikov
,
A.
Vasin
,
D.
Kysil
,
S.
Sevostianov
,
V.
Tertykh
, and
A.
Nazarov
, “
Infrared, raman and magnetic resonance spectroscopic study of SiO2:C nanopowders
,”
Nanoscale Res. Lett.
12
,
292
(
2017
).
28.
L.
Spallino
,
L.
Vaccaro
,
L.
Sciortino
,
S.
Agnello
,
G.
Buscarino
,
M.
Cannas
, and
F. M.
Gelardi
, “
Visible-ultraviolet vibronic emission of silica nanoparticles
,”
Phys. Chem. Chem. Phys.
16
,
22028
22034
(
2014
).
29.
A.
Anjiki
and
T.
Uchino
, “
Visible photoluminescence from photoinduced molecular species in nanometer-sized oxides: Crystalline Al2O3 and amorphous SiO2 nanoparticles
,”
J. Phys. Chem. C
116
,
15747
15755
(
2012
).
30.
A.
Aboshi
,
N.
Kurumoto
,
T.
Yamada
, and
T.
Uchino
, “
Influence of thermal treatments on the photoluminescence characteristics of nanometer-sized amorphous silica particles
,”
J. Phys. Chem. C
111
,
8483
8488
(
2007
).
31.
C. M.
Carbonaro
,
F.
Clemente
,
R.
Corpino
,
P. C.
Ricci
, and
A.
Anedda
, “
Ultraviolet photoluminescence of silanol species in mesoporous silica
,”
J. Phys. Chem. B
109
,
14441
14444
(
2005
).
32.
A. F.
Fehervary
,
L. C.
Kagumba
,
S.
Hadjikyriacou
 et al., “
Photoluminescence and excimer emission of functional groups in light-emitting polymers
,”
J. Appl. Polym. Sci.
87
,
1634
1645
(
2003
).
33.
U.
Pernisz
,
N.
Auner
, and
M.
Baker
, “
Photoluminescence of phenyl- and methylsubstituted cyclosiloxanes
,” in
Silicone and Silicone-Midified Materials. ACS Symposium Series
, edited by
S.
Clarson
 et al. (
American Chemical Society
,
Washington, DC
,
2000
).
34.
M.
Dalla Palma
,
S. M.
Carturan
,
M.
Degerlier
,
T.
Marchi
,
M.
Cinausero
,
F.
Gramegna
, and
A.
Quaranta
, “
Non-toxic liquid scintillators with high light output based on phenyl-substituted siloxanes
,”
Opt. Mater.
42
,
111
117
(
2015
).
35.
M.
D'Amico
,
F.
Messina
,
M.
Cannas
,
M.
Leone
, and
R.
Boscaino
, “
Homogeneous and inhomogeneous contributions to the luminescence linewidth of point defects in amorphous solids: Quantitative assessment based on time-resolved emission spectroscopy
,”
Phys. Rev. B
78
,
014203
(
2008
).
36.
A. V.
Vasin
, “
Structural and luminescent properties of carbonized silicon oxide thin layers
,” in
Functional Nanomaterials and Devices for Electronics, Sensors and Energy Harvesting
, edited by
A.
Nazarov
,
F.
Balestra
,
V.
Kilchytska
, and
D.
Flandre
(
Springer
,
2014
), pp.
297
322
.
37.
L.
Skuja
, “
Optically active oxygen-deficiency-related centers in amorphous silicon dioxide
,”
J. Non-Cryst. Solids
239
,
16
32
(
1998
).
38.
G.
Xin
,
Y.
Meng
,
Y.
Ma
,
D.
Ho
,
N.
Kim
,
S. M.
Cho
, and
H.
Chae
, “
Tunable photoluminescence of graphene oxide from near-ultraviolet to blue
,”
Mater. Lett.
74
,
71
73
(
2012
).

Supplementary Material

You do not currently have access to this content.