Optical Properties of Hybrid Nanomaterials · Optical Properties of Hybrid Nanomaterials. Research...
Transcript of Optical Properties of Hybrid Nanomaterials · Optical Properties of Hybrid Nanomaterials. Research...
K. George ThomasPhotosciences & Photonics Group
National Institute for Interdisciplinary Science and Technology (NIIST), CSIR, Trivandrum- 695 019, INDIA
Optical Properties of Hybrid
Nanomaterials
Research Activities
1. Hybrid nanomaterials for optoelectronic applications
2. Design and study of organic nanostructured materials
3. Light induced processes in functional molecular systems
4. Functional control of molecules on surfaces
5 nm 20 nm
Au nanoparticles Au nanorods Quantum dots
Size and shape does matter….
Physical and chemical properties of matter in the
nanometer scale are distinctly different than in the
macroscopic scale
NIIST NIIST NIIST
Au nanorods
Surface Plasmon (SP) is the collective oscillation of free electrons under the influence of electromagnetic radiation
Shape anisotropy leads to the splitting of surface plasmon bands
Three identical SP modes
Transverse
absorption
Longitudinal
absorption
5 nm 20 nm
Gold nanoparticles and nanorods
400 500 600 700 800 9000.00
0.15
0.30
0.45
0.60
Sphere
Ab
so
rba
nc
e
Wavelength, nm
rod
Extinction Coefficient (λλλλmax - 700 nm) 0.53 x 1010 M-1cm-1
NIISTNIIST
dcore
dML
core
monolayer Coupling of
the size and shape dependent optoelectronic properties of nanomaterials
+the intrinsic functionalities of molecular systems (binding, self-assembly, switching etc.)
S SS
SSS
SS
George Thomas and P. V. Kamat,
Acc. Chem. Res. 2003, 888
George Thomas, Binil and Sudeep,
Pure & Appl Chem. 2002, 74, 1731
H2NH2C
J. Am. Chem. Soc. 2000,
122, 2655-2656
N+
Br
N+
N+ N+Br
N+Br
Br
Br
N+
Br
N+
N+ N+Br
N+Br
N+Br
Br
Br
Langmuir 2002, 18, 3722-3727.
N+
Br
N+
N+ N+Br
N+Br
Br
Br
H215
N-H2C
N+
Br
N+
N+N+Br
N +Br
Br
Br
SCN
O
S
O
S
O
S
OS
O
S
O
S
S
SS
SS
S Au
NCH3
O
S
NH3C
O
S
N CH3
O
S
NH3C O
S
NCH3
O
S
NH3C
O
S
S
SS
SS
S Au
N
H3CCH 3
O
O2N
S
N
H3C
H3C
O
NO 2
S
N
CH 3H3C
O NO 2
S
N
CH 3
CH 3O
O2N
S
N CH 3
CH 3
O
NO 2
S
Au-SP
J. Phys. Chem. B 2002,
106, 18-21
J. Am. Chem. Soc. 2003,
125, 7174-7175
Nano Lett. 2002, 2, 29-35
O
S
O
S
O
S
OS
O
S
O
S
S
SS
SS
S Au
NCH3
O
S
NH3C
O
S
N CH3
O
S
NH3C O
S
NCH3
O
S
NH3C
O
S
S
SS
SS
S Au
N
H3CCH 3
O
O2N
S
N
H3C
H3C
O
NO 2
S
N
CH 3H3C
O NO 2
S
N
CH 3
CH 3O
O2N
S
N CH 3
CH 3
O
NO 2
S
Au-SP
J. Phys. Chem. B 2002,
106, 18-21
J. Am. Chem. Soc. 2003,
125, 7174-7175
Nano Lett. 2002, 2, 29-35
Organic-inorganic hybrid nanomaterials
S SS
SSSSS
How polar is Au nanoparticle surface ?How polar is Au nanoparticle surface ?
CH2O(CH2)5SH CH2O(CH2)8SHCH2SH
III/I peak = 1.18III/I peak = 0.98III/I peak = 0.89
Binil and K. George Thomas J. Phys. Chem. B, 108, 13265 (2004)
Hybrid nanomaterials for charge transferH3C
Ru
NN
NN
N
N
S
S OO OCH3
S
O O
OCH3
2+
2PF6-
Au
Au-Ru2+
J. Phys. Chem. B., 110, 20737 (2006)
J. Phys. Chem. B. 111, 6839-6844 (2007)
S
S
S
Au
J. Phys. Chem. B., 106, 18 (2002
hννννAu
A
B
Au
e
Electron Transfer to Metal Nanocore
Au
hνννν’excimer/
exciplexes
C
(polar solvents)
Unquenched Component
……
bulk Au metal< 3 nm nanoparticle of Au
(conductor) (insulator ?)
unoccupied
occupied
particles
Eg
metal
What are the main deactivation pathways of the photoexcited
fluorophore bound to a metal nanoparticle/QD’s ?
Chromophore Functionalized Metal/QD’s(i) Effect of spacer(ii) Core size (iii) Redox properties
George Thomas and coworkers J. Phys. Chem. B., 106, 18 (2002)
In Situ Synthesis of Metal Nanoparticles
COOH
OH
OHHO
COOH
O
OHO
2H+2e-
O
O
O
O
O
O
OO
O
O
O
O
OO
O
H
H
H
H
H
O
O
O
O
O
O
OO
O
O
O
O
OO
O
H
H
H
H
H
400 600 800 10000.0
0.4
0.8
0 600.0
0.2
0.4
0.6
Ab
so
rban
ce
Wavelength, nm
iii
ii
i
A53
0 n
m
Time, s
100 nm100 nm100 nm100 nm100 nm
400 6000.0
0.1
0.2
0 200 4000.00
0.05
0.10
0.15
Ab
so
rba
nce
Wavelength, nm
A420 n
m
Time, s
i
ii
iii
100 nm100 nm 100 nm100 nm
Hybrid nanomaterials as biosensors
NIISTNIIST
NIISTNIIST
400 500 600 7000.0
0.5
1.0
pH 4.5
Pb2+
Ab
so
rba
nc
e
Wavelength, nm400 600 800
0.5
1.0
Hg2+
pH 4.5
Ab
so
rban
ce
Wavelength, nm
Selective ‘Naked-Eye’ Detection of Lead Ions from Aqueous Media
0 100 200 300
0.8
0.9
1.0
0 10 20 30 40 50
0
4
8
12
Ag nanoparticle
A456/A
429
[Mn+
], µµµµM
∆λ
∆λ
∆λ
∆λ
max n
m
[Pb2+
], µµµµM
CaII PbII CdII MgII ZnII NiIICaII PbII CdII MgII ZnII NiII CaII PbII CdII MgII ZnII NiIICaII PbII CdII MgII ZnII NiII
Fe3+, Cd2+, Cu2+, Hg2+, Ni2+, Zn2+, Mg2+ & Ca 2+.
Pb2+ ions (i) variable co-ordination number up to 12 (ii) flexible bond length (up to 3
Å) and co-ordination geometry.
Yoosaf, Binil, Suresh and George Thomas, J. Phys. Chem. C 111, 12839 (2007)
Au Au Au
N
NSH2C CH3=
BT
Eu3+/ Tb3+
Au Au Au
N
NSH2C CH3=
BT
Eu3+/ Tb3+
AuAu AuAu AuAu
N
NSH2C CH3=
BT
Eu3+/ Tb3+
B. I. Ipe, K. Yoosaf, GeorgeThomas
J. Am. Chem. Soc. 128, 150 (2006)
ΦΦΦΦ τ, τ, τ, τ, ms
Eu-AuBT
Tb-AuBT
0.009
0.038 0.56
0.4
Complex
300 350 600 650 7000
2
4
6
8
10
Eu3+
Inte
nsi
ty (
a.u
.)
Wavelength, nm
Phosphorescent nanomaterials as biosensors
RCH2CH(NH3)CO2
360 nm
520 nm
N
O
NO2
R
NH3
O----
O----
O+
O+
S
CH3
CH3
CO
O
H
Au-MC-amino acid complex
Au
Light-mediated binding and release of amino acid derivatives
Au-MC
360 nm
hνννν /∆/∆/∆/∆
N
H3C CH3
S
O NO2
ON
O
NO2
O----
S
H3CCH3
+
Au-SP
AuAu
Binil, Mahima and George Thomas J. Am. Chem. Soc. 125, 7174 (2003)
HO
HO
NH3
O2CO----
O+
DOPA
Nanostructures of noble metals can convert photons into surface plasmon and within the propagation length, the surface plasmon modes can be decoupled back to light.
Surface plasmons are not diffraction limited
Miniaturizing of devices-propagation of light at nanoscale
Design of nanoscale optoelectronic and photonic devices
Atwater and coworkers Naturematerials, 2003, 2, 229
Can we integrate nanorods into higher order assemblies and tune their optical responses ?
EE
aabb
cc
aabb
cc
BB
EE
aabb
cc
aabb
cc
AA
new red shifted band new blue shifted band
Gluodenis and Foss, J. Phys. Chem. B 106, 9484 (2002).
Theoretical studies on plasmon coupling
Also refer – Schatz and coworkers
El-Sayed and coworkers
Liz-Marzán and coworkers
Mulvaney and coworkers
Cortie and coworkers
Murphy and coworkers
• The end faces of Au nanorods are
dominated by {111} planes and the
side facets by {100} and {110} plane
(El-Sayed and coworkers
Murphy and coworkers)
• Thiols preferentially bind to the
{111} planes of the Au rods
Murphy and coworkers; J. Am. Chem. Soc., 125, 13914 (2003)
• supramolecular approach
• covalent linking
nHierarchical integration of nanomaterials
Crystallographic facets of Au nanorods
Au 111
Au 110 or 100
Crystallographic facets of Au nanorods
Au 111
Au 110 or 100
n
George Thomas and coworkers J. Phys. Chem. B, 108, 13066-13068 (2004).J. Am. Chem. Soc., 127, 6516-6517 (2005). J. Phys. Chem. B, 110, 150-157 (2006).
J. Am. Chem. Soc. 129, 6712-6713 (2007).
Adv. Mater. (2008) (DOI: 10.1002/adma.200703057)
Hierarchical integration of nanomaterials and plasmon coupling
Thomas, K. G., chapter entitled “Surface plasmon resonances in nanostructured materials,”
in Nanomaterials chemistry: Novel aspects and new directions, Rao, C.N.R.; Mueller. A.; Cheetham A. K. (Eds.) Wiley-VCH (2007) pp 185-216.
Connecting nanorods-supramolecular approach
with concentration with time
0 – 8.0 µµµµM15 µµµµM
0-120 min
400 600 800 1000 12000.0
0.2
0.4
0.6
g
a
Ab
so
rba
nc
e
Wavelength, nm
C
SCH2C
OH
O
Au CCH2S
O
HO
Au
George Thomas et al., J. Phys. Chem. B 2004, 108, 13066
400 600 800 1000 12000.0
0.1
0.2
0.3
0.4jd
c
b
a
Ab
so
rba
nc
e
Wavelength, nm
D
HS C
OH
O
Binding unitAssist self assembly
n
400 600 800 1000 12000.0
0.2
0.4
0.6
g
a
Ab
so
rba
nc
e
Wavelength, nm
C 50 nm
50 nm 50 nm
50 nm
B
C D
A
50 nm
50 nm 50 nm
50 nm
B
C D
A
NIIST
NIIST
NIIST
NIIST
1,3-propanedithiol (C3-DT)
1,9-nonanedithiol (C9-DT)
1,8-octanedithiol (C8-DT)
1,6-hexanedithiol (C6-DT)
1,5-pentanedithiol (C5-DT)HS SH
HSSH
HSSH
HS SH
HS SH
nnn
αααα,ωωωω-dithiols
~0.12 nM of Au nanorods S. T. S. Joseph, B. I. Ipe, P. Pramod and
K. George Thomas,
J. Phys. Chem. B., 110, 150 (2006)
Connecting nanorods-covalent approach
Gold nanorods to nanochains
HSHSHSHSSSSS
SHSHSHSH
SSSSSSSS
SHSHSHSH
SHSHSHSH
SSSS
SHSHSHSH
SSSSSSSS
SHSHSHSH
n
SHSHSHSH
SHSHSHSH
SHSHSHSH
SHSHSHSH
SSSS
SSSS
SSSS
SSSSSSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSSSSSS
SSSS
SSSSHSHSHSHS
HSHSHSHSHSHSHSHS
HSHSHSHS
n
n/2
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSSSSSS
SSSSSSSS
SSSS
SSSS
SSSSSSSS
SSSS
α,ω-dithiol
Step 1below critical
concentration
Step 2aabove critical
concentration
HSHSHSHSSSSS
SHSHSHSH
SSSSSSSS
SHSHSHSH
SHSHSHSH
SSSS
SHSHSHSH
SSSSSSSS
SHSHSHSH
n
SHSHSHSHSHSHSHSH
SHSHSHSHSHSHSHSH
SHSHSHSHSHSHSHSH
SHSHSHSHSHSHSHSH
SSSS
SSSS
SSSS
SSSSSSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSSSSSS
SSSS
SSSSHSHSHSHSHSHSHSHS
HSHSHSHSHSHSHSHS
HSHSHSHS
n
n/2
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSSSSSS
SSSSSSSS
SSSS
SSSS
SSSSSSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSSSSSS
SSSSSSSS
SSSS
SSSS
SSSSSSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSS
SSSSSSSS
SSSSSSSS
SSSS
SSSS
SSSSSSSS
SSSS
α,ω-dithiol
Step 1below critical
concentration
Step 2aabove critical
concentration
Step 2b
Shibu, Binil, Pramod, George Thomas, J. Phys. Chem. B 2006,110, 150
200 nm2 00 n m 200 n m
200 n m200 n m
A B
C
200 nm200 nm2 00 n m 200 n m
200 n m200 n m
2 00 n m 200 n m
200 n m200 n m
A B
C
500 s
1000 s
1500 s
600 800 1000 12000.0
0.2
0.4
0.648 min0
jhg
a
Ab
so
rban
ce
Wavelength, nm
NIIST
NIIST
NIIST
HSSH
HS
SH
Effect of linker group
1,6 hexane dithiol; C6DT(~0.84 nm)
1,4-pheylenedimethanethiol; PDT(~0.9 nm)
600 800 10000.1
0.2
0.3
0.4
0.5
0.6
840 nm
8 min0
Ab
so
rban
ce
Wavelength, nm
600 800 10000.0
0.2
0.4
0.6
5 min0
732 nm
Ab
so
rban
ce
Wavelength, nm
50 nm50 nm
Av. angle = 146°°°° Av. angle = 96°°°°
NIISTNIISTNIIST
NIIST
Pramod and George Thomas Adv. Mater. 2008
(DOI: 10.1002/adma.200703057)
SS SS SS SS
Au
nanorod
Au nanorod
λλλλmax = 730 nm λλλλmax = 840 nm
50 nm
50 nm
Flexible linkerFlexible linker Rigid linkerRigid linker
S S
S S
Au
nano
rod A
u
nanoro
d
Effective dipolar overlapEffective dipolar overlap
Probing nanomaterial-molecule junctions
NIIST
NIIST
S S
dimerizationdimerization
S S
50 nm 50 nm
~0.8 nm
NIISTNIIST
NIIST
NIIST
0 1 2 3 2000 4000
0.1
0.2
0.3
0.4
b & c
a
A
(900 nm)
Cysteine / µµµµM
400 600 800 1000 12000.00
0.15
0.30
0.45
0.60
0.75i
a
A
λλλλ / nm
BA
0 1 2 3 2000 4000
0.1
0.2
0.3
0.4
b & c
a
A
(900 nm)
Cysteine / µµµµM
400 600 800 1000 12000.00
0.15
0.30
0.45
0.60
0.75i
a
A
λλλλ / nm
BA
Selective Detection of Cysteine
50 nm 50 nm50 nm
A B C
50 nm 50 nm50 nm
A B C
50 nm 50 nm50 nm
A B C
S COO
NH3
S COO
NH3
S COO
NH3
S
OOC
H3N
S COO
NH3
S
OOC
H3N
S
OOC
NH2S COO
NH3
S
OOC
H3NS COO
NH3 N
N N N N NN N N
Br
N
NNNNN NNNNN
Br Br Br
Br
BrBrBr
BrBr
Br Br Br
Br
BrBrBr
Br
S COO
NH3
S
OOC
H3N
S COO
NH3
S
OOC
H3N
S
OOC
H3N
S
OOC
H3N
N
N N N
Br
N NN N N
Br
N
NNNNN NNNNN
Br Br Br
Br
BrBrBr
BrBr
Br Br Br
Br
BrBr
Br
Au Au Au Au
n
Oligomerization of gold nanorod through end to end self-assembly
Two point electrostatic interaction
HSC
NH3
O
O
NIIST
NIISTNIIST
600 800 1000 12000.00
0.15
0.30
0.45
0.60
0.75
h
a
Ab
so
rba
nc
e
Wavelength, nm
0.0
0.1
0.2
0.3
0.4
0.5
γγ γγ-G
lu-C
ys-G
ly
Met A
sn
Pro
Gln
Arg
Ser
Val
Trp
Tyr
Th
r
Leu
Lys Il
eH
is Gly
Ph
e Glu
Asp
Cys
Ala
∆∆∆∆ A
(900 n
m)
aminoacids/peptide
i) keeping the cysteine thiol group in proteins in the
reduced state and (ii) protecting the cells from
oxidative stress by trapping free radicals that
damage DNA and RNA.
[GSH]: 0 -15 µµµµM
Detection of Glutathione
P. K. Sudeep, S. T. S. Joseph and K. George Thomas,
J. Am. Chem. Soc., 127, 6517 (2005).
C
NH3
CN C
N C
O
H
O
O
O
H
OH
O
SH
Protects body from oxidative
stress
Plasmon coupling in Au nanorods
Dimerization
Oligomerization
400 500 600 700 800 9000.00
0.15
0.30
0.45
0.60
Ab
so
rba
nc
e
Wavelength, nm
600 800 100012000.0
0.2
0.4
0.648 min0jhg
a
Ab
so
rban
ce
Wavelength, nm
(900 nm)
400 600 800 1000 12000.00
0.15
0.30
0.45
0.60
0.75i
a
A
λλλλ / nm
A
(900 nm)
400 600 800 1000 12000.00
0.15
0.30
0.45
0.60
0.75i
a
A
λλλλ / nm
A
Au
Au Au
Au Au Au Au
Tasting Edge Effects
Bocquet, Am. J. Phys. 2007, 75, 148.
Divergence of electric field and charge accumulation at the edges or corners
Wang and co workers, small 2007, 3, 2103
Electric-field-intensity enhancement in nanoparticles and nanorods-FDTD calculation
Thomas F. Jaramillo, et al Science 2007, 317, 100
Identification of active edge sites for electrochemical H2 evolution from MoS2 nanocatalysts
Edges are very reactive
Edge effect
10 nm 5 nm 2 nm 2 nm
600 800 10000.00
0.15
0.30
0.45 ∆λ ∼ ∆λ ∼ ∆λ ∼ ∆λ ∼ 60 nm
ba
Ab
sorb
an
ce
Wavelength, nm
HRTEM studies
20 nm 5 nm
- +
Electric field at the edges of anisotropic nanostructures
NIIST
NIIST
NIIST NIIST
NIIST NIIST
-----
-
--
- -------
-
--
Au nanorods
++++
++ ++++
++
++++
+++
+++
++
++++
++
++++
++
++++
++
++++
++ ++++
++
++++
+++
+++
++
++++
++
++++
++
++++
++- - -
Pramod, Shibu and George Thomas
J. Am. Chem. Soc. , 129, 6712 (2007)
15
30
45
60
75
4.5
Aspect ratio3.73.0
2.25.7
1.8
Pla
smon
Sh
ift,
nm
Np size, nm
C
Optimizing the shell thickness of Quantum dots
0 1 2 3 40.0
0.2
0.4
0
100
200
αα αα, M
-1
ΦΦ ΦΦL
ZnS monolayers
Vinayakan. Shanmugapriya, Nair, Ramamurthy, George Thomas
J. Phys. Chem. C 111, 10146 (2007)
Electric field at the edges
NIIST NIISTNIIST
Self-organization of molecules on surface
PhenyleneethylenesPhenyleneethylenes…………..
Rigid
molecules
Maintains ππππ-
conjugation
George Thomas and coworkersJ. Phys. Chem. A 110, 4329-4337 (2006)
Can the optoelectronic properties of same molecules on surface modulated by varying their organization
J. Phys. Chem. A, 110, 5642-5649 (2006).
1.3 nm
Type II
OO
OO
OO
OO
OO
OO
OOa
b
) 70°
OO
O
O
O
O
O
O
O
O
O
O
O
O
) 83°
b
a
Type I
Yoosaf, James, Ramesh, Suresh, and George Thomas,
J. Phys. Chem. C. 111, 14933-14936 (2007).
NIIST NIIST
Functional control of molecules on surfaces - STM studies
Former doctoral students
Dr. V. Biju
Dr. Zeena S. Pillai Dr. P. K. Sudeep
Dr. Binil Itty Ipe
Dr. P. V. James
Dr. K. Yoosaf
Dr. S. T. Shibu Joseph
Dr. P. Pramod
R. Vinayakan
A. R. Ramesh Pratheesh V. NairJino George
Jatish Kumar M. Shantil Anoop Thomas
Present students
Professor M. V. George (NIIST)
Collaborators: Dr. Prashant V. Kamat (Notre Dame, USA)Dr. C. H. Suresh (NIIST)
Dr. P. Ramamurthy (University of Madras)
(i) CSIR (Government of India)
Professor T. K Chandrasekhar (Director, NIIST)
Dr. Suresh Das (NIIST)
Former Directors of NIIST
Members of Photosciences and Photonics Group
(ii) Nanoscience and Technology Initiative of DST(Government of India)
Funding from
Thank you