close

Вход

Забыли?

вход по аккаунту

?

Silicon nanoparticles with chemically tailored surfaces.

код для вставкиСкачать
Full Paper
Received: 25 August 2009
Revised: 23 October 2009
Accepted: 10 November 2009
Published online in Wiley Interscience: 22 December 2009
(www.interscience.com) DOI 10.1002/aoc.1602
Silicon nanoparticles with chemically tailored
surfaces
Andrew S. Heintza , Mark J. Finkb and Brian S. Mitchella∗
Silicon nanoparticles are useful materials for optoelectronic devices, solar cells and biological markers. The synthesis of
air-stable nanoparticles with tunable optoelectronic properties is highly desirable. The mechanochemical synthesis of silicon
nanoparticles via high-energy ball milling produces a variety of covalently bonded surfaces depending on the nature of
the organic liquid used in the milling process. The use of the C8 reactants including octanoic acid, 1-octanol, 1-octaldehyde
and 1-octene results in passivated surfaces characterized by strong Si–C bonds or strong Si–O bonds. The surfaces of the
nanoparticles were characterized by infrared spectroscopy and nuclear magnetic resonance spectroscopy. The nanoparticles
were soluble in common organic solvents and remarkably stable against agglomeration and air oxidation. The luminescence
c 2009
and optical properties of the nanoparticles were very sensitive to the nature of their passivating surface. Copyright John Wiley & Sons, Ltd.
Supporting information may be found in the online version of this article.
Keywords: mechanochemistry; silicon–carbon bonds; silicon nanoparticles; mechanochemical synthesis; organosilicon
Introduction
236
Silicon nanoparticles have shown immense promise as materials
for use in optoelectronic devices,[1 – 3] solar cells,[4] nanoparticle
lasers,[5,6] and as fluorescent biomarkers.[7,8] Quantum confinement of electrons in small silicon nanoparticles (Bohr exciton
radius less than 5 nm)[9,10] results in size-dependent bandgaps with
high photoluminescent quantum yields in the visible spectrum.[11]
The photoluminescence (PL) typically arises from size-dependent
core states, which may be influenced by the presence of surface
states which depend profoundly on the nature of the passivating
surface. For instance, a native oxide surface layer can cause a significant decrease in silicon nanoparticle PL efficiency,[12,13] whereas
a nanoparticle surface linked molecularly through covalent Si–C
and Si–O bonds has been shown to preserve PL through surface
passivation of electronic states.[14]
Although many routes to the synthesis of stable alkyl, alkoxy and
siloxy passivated silicon nanoparticles have been developed,[15 – 27]
most require the use of highly reactive and corrosive chemicals
and involve the modification of metastable nanoparticles with
highly reactive silicon surfaces.[28] An example of direct reactions
with pure silicon surfaces include the formation of strong Si–C
and Si–X bonds through the mechanical scribing of flat silicon
surfaces in the presence of a reactive organic liquid.[28 – 32]
The reactive sites at the scribed surface have been modeled
on Si(100) and Si(111) surfaces which contain surface-bound
zwitterionic disilene and silyl radicals, respectively.[33 – 35] Recently,
we introduced a new method for the simultaneous production
of silicon nanoparticles and the chemical passivation of the
particle surface using reactive high-energy ball milling (HEBM).[36]
By subjecting pieces of single-crystal silicon to HEBM in the
presence of a liquid alkyne, the nanoparticle surface undergoes a
direct reaction with the liquid media, successfully passivating the
surface while the particles are simultaneously reduced into the
nano-domain by repeated material fracture.[28 – 30] The resulting
passivated nanoparticles possess alkyl/alkenyl groups covalently
Appl. Organometal. Chem. 2010, 24, 236–240
linked through Si–C bonds and are soluble in the reactive medium.
They can be subsequently recovered by centrifugation and solvent
evaporation. The nanoparticles can be redispersed in organic
solvents and show no tendency toward air oxidation.
We now report that this method is not limited to alkynes but
can be extended to other reactive organic species as well. This
allows for a convenient way to chemically tailor the surface for
desirable properties. Specifically, silicon was milled with 1-octene,
1-octaldehyde, octanoic acid and 1-octanol as the respective
reactive organic liquids. The eight-carbon chain for each functional
group was selected for the purpose of consistency and for ease of
comparison to previous work involving 1-octyne. Infrared and NMR
are used to characterize the nanoparticle surface while UV–vis and
photoluminescence were used to probe the nanaoparticle optical
states. The resulting nanoparticles are air-stable and soluble in
most organic solvents.
Experimental
Production of Silicon Nanoparticles
A 1.0 g aliquot of silicon pieces of 99.95% purity obtained from
Sigma-Aldrich were placed in a stainless steel milling vial along
with two stainless steel milling balls, each with a diameter of 1.2 cm
and weighing approximately 8.1 g. In a glovebox under nitrogen
atmosphere, the vial was loaded, filled with approximately 25 ml
∗
Correspondence to: Brian S. Mitchell, Department of Chemical and Biomolecular Engineering, Tulane University, 300 Lindy Boggs, 6283 St Charles Ave, New
Orleans, LA 70118, USA. E-mail: brian@tulane.edu
a Department of Chemical and Biomolecular Engineering, Tulane University, 300
Lindy Boggs, 6823 St Charles Ave, New Orleans, LA 70118, USA
b Department of Chemistry, Tulane University, 2015 Percival Stern Hall, 6283 St
Charles Ave, New Orleans, LA 70118, USA
c 2009 John Wiley & Sons, Ltd.
Copyright Silicon nanoparticles with chemically tailored surfaces
of the desired liquid media, and then tightly sealed. For the
functionality comparison, 1-octyne of purity ≥98.0%, 1-octene of
purity ≥98%, octanoic acid of purity ≥98%, 1-octonal of purity
≥99% and 1-octanol of purity ≥99% were all obtained from Sigma
Aldrich. After charging and sealing, the milling vial was placed in
a SPEX 8000-D Dual Mixer/Mill, and HEBM was performed over
various lengths of time.
Characterization
FTIR spectra were obtained at 1 cm−1 resolution with 1000
scans using a Bruker IFS-55 spectrometer. For FTIR analysis, the
nanoparticle solutions obtained from centrifugation supernatant
were placed in a vacuum oven for solvent removal, and were
re-dissolved in carbon disulfide then placed on a salt plate where
the carbon disulfide was allowed to evaporate. NMR spectra
were obtained on a Bruker Avance 300 MHz high-resolution NMR
spectrometer. For NMR analysis, the nanoparticles were placed
in a vacuum oven for solvent removal, and were dispersed
in methylene chloride-d2 . The excitation–emission spectra and
photoluminescence data from the nanoparticles were obtained
using a Varian Cary Eclipse spectrofluorimeter. UV–vis spectra of
the nanoparticles dissolved in hexane were obtained on a Cary 50
spectrophotometer.
Results and Discussion
Infrared and NMR Characterization
Appl. Organometal. Chem. 2010, 24, 236–240
Figure 1. FTIR spectrum of passivated silicon nanoparticles produced
by milling for 24 h in (a) 1-octyne, (b) 1-octene, (c) 1-octanol, (d) 1octaldehyde and (e) octanoic acid.
in the 13 C{1 H}NMR spectrum by olefinic resonances at 125,
129 and 142 ppm. On this basis, two predominate structures
were proposed, a surface-bound disilacyclobutene from [2 + 2]
cycloaddition, and a surface-bound vinyl silane. The linear vinyl
silane product originates from the reaction of a surface silyl
radical with the triple bond of the octyne followed by hydrogen
abstraction by the vinyl radical from the surrounding solvent
(octyne). Figure 2 shows the structure of these products as well as
the products derived from all of the organic liquids studied.
The FTIR spectrum obtained on passivated silicon nanoparticles
formed by milling in 1-octene for 24 h is shown in spectrum (b). The
nanoparticle spectrum shows clear evidence of an organic layer as
shown by the CH peaks in the 2800–3000 cm−1 range, and that
the surface is protected from oxidation, as evidenced by the lack of
a significant peak in the SiO region from ∼1000–1200 cm−1 . Three
peaks present in the pure 1-octene spectrum at 3076, 1641 and
908 cm−1 , attributable to the carbon–carbon double bond,[33]
are non-existent in the nanoparticle spectrum, indicating that
the C C is responsible for the surface reaction. Weak vibrations
attributable to the Si–C bond are probably obscured by the broad
and slightly overlapping bands at 864 and 1060 cm−1 . In analogy
to the reaction with 1-octyne, a [2 + 2] cycloadduct and a linear
alkylsilane structure are proposed.
Spectrum (c) shows a FTIR spectrum obtained for silicon
nanoparticles passivated with 1-octanol. Again, the nanoparticle
spectrum shows clear evidence of an organic layer as shown by the
peaks in the 2800–3000 cm−1 range. The 1-octanol reacts by O–H
addition to silicon atoms on the surface generating two surface
c 2009 John Wiley & Sons, Ltd.
Copyright www.interscience.wiley.com/journal/aoc
237
Figure 1 shows FTIR spectra obtained for thin films of passivated
silicon nanoparticles milled in various organic solvents (reactants).
Because of the solubility of the nanoparticles in organic solvents,
it is possible to corroborate the structures of the surface-bound
organic monolayer by using 13 C{1 H} and 1 H nuclear magnetic
resonance spectroscopy and a series of multipulse DEPT tests.
It is important to note that, for all functionalities, the 13 C{1 H}
spectrum shows a single methyl resonance and a distinct number
of methylene carbons, indicating a uniform alkyl carbon chain.
However, for the point of brevity, only the peaks of interest found
during the NMR experiments are discussed. Full NMR spectra are
included in the supplementary materials.
All of the FTIR spectra, irrespective of the reactive liquid used in
the milling, indicate the formation of a tenacious organic surface
layer on the silicon nanoparticle. The prominent νs (C–H) stretching
vibrations in the 2800–3000 cm−1 range and the weaker scissoring
vibrations (δ, C–H) around 1460 cm−1 are totally consistent with
the alkyl backbone of the surface-bound molecules.[37] In the case
of the polar substrates: 1-octanol, 1-octaldehyde and 1-octanoic
acid (Fig. 1c–e), there is also a broad feature in the range of
3200–3500 cm−1 which is attributed to the O–H stretch of a
surface-bound silanol group. A peak near 1050 cm−1 of moderate
intensity accompanies the O–H stretch and is attributed to the
Si–O stretching vibration of the surface-bound silanol.
Spectrum (a) is the FTIR spectrum of a thin film of 1-octyne. A
previous version of this spectrum has been published. The lack of
alkyne C–H and C C stretching vibrations and the appearance
of weak C C stretching vibrations (∼1600 cm−1 ) is particularly
noteworthy. A weak vibration at ∼3050 cm−1 appears as a broad
shoulder to a much stronger alkyl νs (CH) vibration and is probably
the νs (CH) of the vinylic hydrogens. This clearly indicates that
the C C triple bond has been reduced to a C C double bond
at the surface of the silicon nanoparticle. This is corroborated
A. S. Heintz M. J. Fink and B. S. Mitchell
R
HC O
Si Si Si Si
Si
Si
R
OH
CH OH
Si Si
Si
Si
Si Si
R
HC CH2
Si Si Si Si
Si
Si
HC
Si
Si
Si
Si
C CH
Si Si Si Si
Si
Si
R
R
CH2
R
CH
R
O
C
H
RC≡CH
Si
RCH=CH2
RCOOH
H2C
Si
Si
Si
Si
R
C
OH
Si
Si
Si
Si
ROH
OH
Si
Si
Si
Si
O
O
Si Si Si Si
Si
Si
R
C
R
O
Si
Si
Si
Si
O
O
Si Si Si Si
Si Si Si
Figure 2. Summary of the surface structures of silicon nanoparticles passivated by 1-octyne (previously presented), 1-octene, 1-octaldehyde, octanoic
acid and 1-octanol. The silanol structures (Si–OH) are the result of ambient oxidation of Si–H groups or hydrolysis of strained Si–O rings.
H
Si
[O]
CH2
O CH
Scheme 1. Oxidation of unstable Si–H bonds on nanoparticle surface.
Si Si
Si
238
moieties: an alkoxy silane and an Si–H species. Surface-bound
Si–H groups, however, are highly susceptible to air oxidation and
are readily converted to a surface-bound silanol (Si–O–H).[38,39]
A strong peak can be observed at 1090 cm−1 in the Si–O region
and is ascribed to the strong Si–O–C linkage that is formed at
the surface. An O–H band over the 3200–3500 cm−1 range shows
the involvement of a silanol group from the insertion of oxygen
into a Si–H bond upon air oxidation (Scheme 1). The 13 C{1 H}
NMR spectrum obtained on the 1-octanol passivated silicon
nanoparticles exhibits a resonance peak at 63 ppm indicating
an alkoxy carbon. A broad resonance in the 1 H NMR spectrum at
3.5 ppm is attributed to the methylene hydrogens alpha to the
oxygen atom. A partially overlapping resonance at 3.6 ppm which
is approximately half the area of the previous peak is ascribed to
the surface-bound silanol.
Spectrum (d) was obtained on passivated silicon nanoparticles
formed by milling in 1-octaldehyde for 24 h. It also exhibits welldefined peaks in the 2800–3000 cm−1 range. A broad absorption
at 1100 cm−1 , indicative of a Si–O stretching vibration, and a
broad OH band covering the range 3200–3500 cm−1 is also
observed. The diminished peak (relative to the pure octaldehyde)
at ∼1733 cm−1 is assigned as a carbonyl vibration typical of
normal unconjugated alkyl aldehydes.[40] It is not clear if this
residual carbonyl group is the result of a physisorbed species or
the product of an unknown chemical reaction at the surface.
The 13 C{1 H} shows two distinct resonances at 64 and 72 ppm,
which suggests that there are two different surface-bound
structures. While both peaks are assigned to a carbon bound to
an oxygen atom, the slight difference in chemical shift implies two
www.interscience.wiley.com/journal/aoc
R
R
OH
Si
Si Si
Si
HO
HO
hydrolysis
CH2
CH
Si Si
Si
Si Si
Si
Scheme 2. Hydrolysis of the cycloaddition product formed during milling
with 1-octaldehyde.
unique chemical environments. A set of three broad resonances
centered at ∼3.8 ppm corresponds to an oxygen-bound CH
group as well as the silanol group. The cyclic 1,2-disilaoxetane
structure is attributed to the [2 + 2] cycloaddition of the aldehyde
to silicon dimer pairs at the surface. The 1,2-disilaoxetane
structure has been proposed for the reaction of acetone[41] and
aldehydes[42] with clean silicon surfaces. Upon exposure to air,
the cycloadduct product undergoes partial hydrolysis as shown in
Scheme 2, which accounts for the surface-bound silanol and for
the secondary alcohol which together contributes to the broad
OH band observed in the FTIR spectrum. Although no analogous
reactions have been reported for the reaction with molecular
1,2-disilaoxetanes with water, the methanolysis of the strained
Si–O–C in siloxetanes has been reported.[43]
Spectrum (e) was obtained on passivated silicon nanoparticles
formed by milling in octanoic acid for 24 h. The presence of strong
peaks at 1530 and 1591 cm−1 and at 1441 cm−1 is characteristic of
the carbonyl vibrations of a bidentate carboxylate group.[44] These
IR peaks correspond to the asymmetric and symmetric vibrational
combinations, respectively.[45] It is likely that the octanoic acid
is bound predominately to the surface via a bridging bidentate
COO− structure. Such structures have been observed for the
reaction of carboxylic acids on a Ge(100) 2×1 surface.[46] Although
no comparable structures have been unambiguously identified on
a comparable silicon surface, theoretical calculations suggest that
a bidentate structure should be more stable than a monodentate
c 2009 John Wiley & Sons, Ltd.
Copyright Appl. Organometal. Chem. 2010, 24, 236–240
Silicon nanoparticles with chemically tailored surfaces
Table 1. PL data obtained on luminescent silicon nanoparticles produced by milling in various organic solvents for 24 h
Passivating molecule
functional group
1-Octyne
1-Octene
1-Octaldehyde
Octanoic acid
1-Octanol
Excitation wavelength of
maximum observed
emission intensity (nm)
Wavelength of
maximum observed
emission (nm)
Stokes shift (nm)
Intensity of maximum
emission (a.u.)
360
320
440
440
290
∼435
∼394
∼522
∼518
∼406
75
74
82
78
116
∼210
∼72
∼48
∼21
∼12
one.[47] A small peak at 1708 cm−1 is assigned to the νs (C O) of
a carboxylic acid bound, indicating that a small fraction binds in a
monodentate fashion.
The broadened absorbance at 3300 cm−1 is assigned as an
OH stretching vibration of a surface-bound silanol. A broad peak
at 1080 cm−1 corresponds to the SiO stretch of the silanol. This
silanol is probably the result of surface oxidation of the Si–H bond
formed from the polar addition of the OH bond of the carboxylic
acid group (COOH) across the silicon surface.
A combination of 13 C{1 H} NMR and DEPT spectroscopy shows
two methylene carbons at 63 and 65 ppm. These peaks were
attributed to the methylene carbons adjacent to the carboxylate
group on the basis of their downfield chemical shifts. The
carboxylate carbons could not be observed, probably due to their
long relaxation. Although only one general bonding structure is
present, the peak shifts of 63 and 65 ppm were attributed to
conformational differences resulting from multiple reaction sites.
The bidentate carboxylate can span between adjacent silicon
atoms within a dimer row or alternatively between different rows
of silicon dimers. This results in cyclic structures containing two
and three silicon atoms, respectively, each with a slightly different
shift in the 13 C{1 H} NMR spectrum. Finally, a peak at 4.1 ppm is
found in the 1 H spectrum, which can be attributed to the silanol
proton.
Photoluminesence and UV–Vis Spectra
Appl. Organometal. Chem. 2010, 24, 236–240
size-dependent Stokes shift (due to the widening bandgap).[48 – 50]
Because the Stokes shifts are relatively constant, this indicates
that the particle size distributions between the samples are
similar, and that the differences in emissions are more likely
to result from effects due to the different passivating molecules.
Passivated silicon nanoparticles produced in 1-octanol display a
slightly different behavior, which seems to indicate a more narrow
size distribution. This can be explained through a more limited
solubility of the nanoparticles in the milling solution, which only
allows nanoparticles of very small sizes to remain in solution.
In contrast to the photoluminescence behavior, the absorption
spectra of the different nanoparticles are more variable. Figure 3
is a summary of different UV–vis spectra. Most show no
discernable wavelength maximum greater than 200 nm but
exhibit an absorbance tailing into the visible. This behavior is
highly characteristic of an indirect semiconductor such as silicon.
Exceptions to this behavior are octanoic acid, which shows a small
peak with a maximum at 275 nm, and octaldehyde, which shows
a major absorption with λmax = 290 nm. This difference in optical
absorption behavior is unusual and is more reminiscent of direct
band gap semiconductors. The effect of these absorptions on the
composition of the surface is currently being investigated.
Conclusions
We have demonstrated that a mechanochemical method for the
simultaneous production and passivation of silicon nanoparticles
is not limited merely to n-alkynes, but in fact is also effective
with normal alkenes, aldehydes, carboxylic acids and alcohols. The
c 2009 John Wiley & Sons, Ltd.
Copyright www.interscience.wiley.com/journal/aoc
239
Table 1 lists a summary of photoluminescence (PL) data obtained
on silicon nanoparticles produced by milling in the various organic
solvents for 24 h. All of the nanoparticles display an observable
blue luminescence at room temperature typical of nanoparticles
with alkyl or alkoxy surfaces. In addition, all of the particles show the
characteristic bathochromic shift of the emission wavelength with
increasing excitation wavelength consistent with a polydisperse
ensemble of nanoaparticles. Selective excitation of a population of
larger nanoparticles at longer wavelength results in an emission at
corresponding longer wavelengths due to their wider bandgaps.
The positions of the emission bands for 1-octyne (λem =
435 nm) and 1-octene (λem = 394 nm) are fairly similar but the
longer wavelength in the 1-octyne species suggests possible
conjugation of the C C bond to the silicon nanoparticle. The PL
from nanoparticles with surfaces of the more polar 1-octaldehyde
(λem = 522 nm) and 1-octanoic acid (λem = 518 nm) exhibit
a significant bathochromic shift. In contrast, 1-octanol gives a
maximum of λem = 406 nm which is more reminiscent of particles
derived from the non-polar 1-octene and 1-octyne.
With the exception of the silicon nanoparticles produced in
1-octanol, the Stokes shifts at maximum emission are relatively
consistent (within ∼8 nm). It is well established that, for quantum
dots, decreasing particle size results in an increase in the
Figure 3. UV–vis absorption spectra of functionalized nanoparticles.
A. S. Heintz M. J. Fink and B. S. Mitchell
scope of this process should be expanded to other functional
groups to give nanoparticles with unique optical properties. The
facile one-step generation of silicon nanoparticles with diverse
surfaces, and their corresponding unique optical properties,
should greatly augment their use as materials in optoelectronic
applications.
Acknowledgments
The authors acknowledge the financial assistance of NSF (CMMI0726943) and of NASA (NNX08AP04A), administered by the
Tulane Institute of Macromolecular Engineering and Science.
The assistance of Steffen Hallmann, Li Kuang and Ted Shaner
in the preparation of selected spectroscopic data is also greatly
appreciated.
Supporting information
Supporting information may be found in the online version of this
article.
References
[1] S. Pillai, K. Catchpole, T. Trupke, G. Zhang, J. Zhao, M. Green, Appl.
Phys. Lett. 2006, 88, 161102.
[2] L. Raniero, S. Zhang, H. Aqyas, I. Ferreira, R. Igreja, E. Fortunato,
R. Martins, Thin Solid Films 2005, 487, 170.
[3] O. Boyraz, B. Jalili, Optics Express 2005, 13, 796.
[4] M. C. Beard, K. P. Knutsen, P. Yu, J. M. Luther, Q. Song, W. K. Metzger,
R. J. Ellingson, A. J. Nozik, Nano Lett. 2007, 7, 2506.
[5] A. Fotjik, J. Valenta, I. Peant, M. Kalal, P. Fiala, J. Mater. Process
Technol. 2007, 181, 88.
[6] G. Belomoin, J. Therrien, A. Smith, S. Rao, R. Twesten, S. Chaieb,
M. H. Nayfeh, L. Wagner, L. Mitas, Mater. Res. Soc. Symp. Proc. 2002,
703, 475.
[7] L. Wang, V. Reipa, J. Blasic, Bioconjug. Chem. 2004, 15, 409.
[8] D. R. Larson, W. R. Zipfel, R. M. Williams, S. W. Clark, M. P. Bruchez,
F. W. Wise, W. W. Webb, Science 2003, 300, 1434.
[9] J. M. Buriak, Chem. Commun. (Camb.) 1999, 1051.
[10] J. P. Proot, C. Delrue, G. Allan, Appl. Phys. Lett. 1992, 61, 1948.
[11] M. H. Nayfeh, E. V. Rogozhina, L. Mitas, Synthesis, Functional. Surf.
Treatment Nanopart. 2003, 173.
[12] M. A. Tischler, R. T. Collins, J. H. Stathis, J.C. Tsang, Appl. Phys. Lett.
1992, 60, 639.
[13] W. Shockley, Phys. Rev. 1952, 835.
[14] F. A. Reboredo, G. Galli, J. Phys. Chem. B 2005, 109, 1072.
[15] L. H. Lie, M. Duerdin, E. M. Tuite, A. Houlton, B. R. Horrocks,
J. Electroanalyt. Chem. 2002, 538-539, 183.
[16] M. H. Nayfeh, N. Barry, J. Therrien, O. Akcakir, E. Gratton,
G. Belomoin, Appl. Phys. Lett. 2001, 78, 1131.
[17] B. Sweryda-Krawiec, T. Cassagneau, J. H. Fendler, J. Phys. Chem. B
1999, 103, 9524.
[18] R. S. Carter, S. J. Harley, P. P. Power, M. P. Augustine, Chem. Mater.
2005, 17, 2932.
[19] J. Zou, R. K. Baldwin, K. A. Pettigrew, S. M. Kauzlarich, Nano Lett.
2004, 4, 1181.
[20] R. D. Tilley, J. H. Warner, K. Yamamoto, I. Matsui, H. Fujimori, Chem.
Commun. (Camb.) 2005, 1833.
[21] K. A. Pettigrew, Q. Liu, P. P. Power, S. M. Kauzlarich, Chem. Mater.
2003, 15, 4005.
[22] D. Neiner, H. W. Chiu, S. M. Kauzlarich, J. Am. Chem. Soc. 2006, 128,
11016.
[23] Z. Ding, B. M. Quinn, S. K. Haram, L. E. Pell, B. A. Korgel, A. J. Bard,
Science (Washington, DC) 2002, 296, 1293.
[24] Z. F. Li, E. Ruckenstein, Nano Lett. 2004, 4, 1463.
[25] Z. F. Li, M. T. Swihart, E. Ruckenstein, Langmuir 2004, 20, 1963.
[26] J. D. Holmes, K. J. Ziegler, R. C. Doty, L. E. Pell, K. P. Johnston,
B. A. Korgel, J. Am. Chem. Soc. 2001, 123, 3743.
[27] J. Zou, P. Sanelle, K. A. Pettigrew, S. M. Kauzlarich, J.ClusterSci. 2006,
17, 565.
[28] M. P. Stewart, J. M. Buriak, Comm. Inorgan. Chem. 2002, 23, 179.
[29] Y.-C. Liao, J. T. Roberts, J. Am. Chem. Soc. 2006, 128, 9061.
[30] T. L. Niederhauser, Y.-Y. Lua, Y. Sun, G. Jiang, G. S. Strossman,
P. Pianetta, M. R. Linford, Chem. Mater. 2002, 14, 27.
[31] G. Jiang,
T. L. Niederhauser,
S. A. Fleming,
M. C. Asplund,
M. R. Linford, Langmuir 2004, 20, 1772.
[32] M. Stewart, E. Robbins, T. Geders, M. Allen, H. C. Choi, J. Buriak, Phys.
Stat. Solidi A 2000, 182, 109.
[33] H. N. Waltenburg, J. T. Yates Jr, Chem. Rev. (Washington, DC) 1995,
95, 1589.
[34] S. F. Bent, Surf. Sci. 2002, 500, 879.
[35] J. M. Buriak, Chem. Rev. 2002, 102, 1271.
[36] A. S. Heintz, M. J. Fink, B. S. Mitchell, Adv. Mater. (Weinheim) 2007,
19, 3984.
[37] R. M. Silverstein, F. X. Webster, D. J. Kiemle, Spectrometric Identification of Organic Compounds, 7th edn. John Wiley and Sons Inc.:
Hoboken, NJ, 2005.
[38] S. Rivillon, R. T. Brewer, Y. J. Chabal, Appl. Phys. Lett. 2005, 87,
173118.
[39] S. Rivillon, Y. J. Chabal, L. J. Webb, D. J. Michalak, N. S. Lewis,
M. D. Halls, K. Raghavachari, Vacuum Sci. Technol. 2005, A23, 1100.
[40] L.J. Bellamy, The Infrared Spectra of Complex Molecules. ChapmanHall: London, 1975.
[41] S. A. Saraireh, P. V. Smith, M. W. Radny, S. Scofield, B. V. King, Surf.
Sci. 2008, 602, 3484.
[42] Y.-Y. Lua, W. J. J. Fillmore, M. R. Linford, Appl. Surf. Sci. 2004,
231–232, 323.
[43] W. Ando, A. Sekiguchi, T. Sato, J. Am. Chem. Soc. 1982, 104, 6830.
[44] J. Lecomte, Rev. Opt. 1949, 353.
[45] G. Davidson, Spectrosc. Prop. Inorgan. Organometall. Compounds
2007, 39, 324.
[46] M. A. Filler, J. A. Van Deventer, A. Kueng, J., S. F. Bent, J. Am. Chem.
Soc. 2006, 128, 770.
[47] M. Carbone, R. Caminiti, Surf. Sci. 2008, 602, 852.
[48] T. J. Liptay, L. F. Marshall, P. S. Rao, R. J. Ram, M. G. Bawendi, Phys.
Rev. B 2007, 76, 155314.
[49] K. F. Lin, H. M. Cheng, H. C. Hsu, L. J. Lin, W. F. Hsieh, Chem. Phys. Lett.
2005, 409, 208.
[50] L. K. Pan, C. Q. Sun, J. Appl. Phys. 2004, 95, 3819.
240
www.interscience.wiley.com/journal/aoc
c 2009 John Wiley & Sons, Ltd.
Copyright Appl. Organometal. Chem. 2010, 24, 236–240
Документ
Категория
Без категории
Просмотров
3
Размер файла
236 Кб
Теги
chemical, silicon, surface, tailored, nanoparticles
1/--страниц
Пожаловаться на содержимое документа