NORTHWESTERN
UNIVERSITY
NSF - PREM - MRSEC
Synthesis and Characterization of Rare
Earth Nanomaterials and their Biological
and Photonic Applications
Dhiraj Sardar
Department of Physics
University of Texas at San Antonio
March 10 and 11, 2011
Outline
•
•
•
•
•
•
•
•
Introduction to Rare Earths
Methods
Important Facilities
Results – Theoretical and Experimental
Potential Applications
UTSA Physics Department -PREM
PREM Students
PREM Publications and Acknowledgements
Introduction to Rare Earths
Electron charge distribution in different orbitals for RE ions
showing the shielding of 4f electrons by outer 5s and 5p electrons
Electronic Configuration (RE3+)
: Incomplete inner 4fN orbital
: [Xe]4fN5s25p6(N=113)
Energy levels of trivalent rare earths (RE3+ )
Optical Properties
: Strong absorption and fluorescence
: Wide range of excitation and emission (UV-VIS-IR)
Applications
: Lasers, Display, Sensor, Therapy,
Biomedical imaging, etc.
Methods
1. Synthesis
• Solvothermal/Hydrothermal
• Precipitation
• Thermolysis
2. Morphology Characterization
• XRD, EDX
• SEM, TEM, STEM
• AFM
3. Optical Characterization
• Refractive Index
• Optical Absorption/Reflection/Scattering
• Steady State Emission
• Fluorescence Lifetime
• Optical Gain
• Efficiency(Internal, External, Conversion, Slope)
• FTIR/Raman
Important Facilities
 Laser Research Laboratory
 Lasers: Argon, Nd:YAG, Ti:Sapphire,
Diode (Vis-IR)
 Cary-14 Spectrophotometer
 SPEX 1250M Monochromator
 Cryogenic Cryostat
 Microscopy Laboratory
 STEM w/EDX
 HR-TEM w/EDX
 AFM
 Raman
 XRD
JEOL-ARM200F(0.06 nm resolution)
RESULTS
STEM imaging of the Nd3+ distribution
Nd3+:Sc2O3
Blue = Scandium , Red = Oxygen
Theoretical (Judd-Ofelt Formalism)
Radiative Process:
J
64 4e2 n(n2  1)
t
2


Arad ( J  J ) 


|

J
U

J
|
t
t  2,4,6
3h(2 J  1) 3
9
Arad ( J  J )
 J 
(Judd-Ofelt Model)
Major Nonradiative Processes:
4F
7/2
AET
1.Multiphonon relaxation (Amp)
2.Energy transfer between ions (AET)
3.Hydroxyl content/High frequency vibrational groups (AOH)
4.Impurity (Aimp)
Anr  Amp  AET  AOH  Aimp
( fl ) 1  Arad  Anr
4S
Amp
980nm
Pump
1550nm AOH
550nm
650nm
AET
4I
15/2
Er3+
Radiative Quantum Efficiency:
 fl
Arad


 rad
Arad  Anr
3/2
4F
9/2
4I
9/2
4I
11/2
4I
13/2
Arad=radiative decay rate
Anr=nonradiative decay rate
Nd3+:Y2O3 Absorptions from Ceramic and Embedded in Polymers
35
30
G5/2 +1G(1)7/2+2H(2)11/2
-1
Absorption Coefficient (cm )
25
Nd3+:Y2O3 Ceramic
20
4
2
2
2
2
G11/2+ K15/2 + G(1)9/2+ D(1)3/2
4
H(2)9/2 + F5/2
15
4
10
4
F7/2 +4S3/2
G7/2 +2K13/2 + 4G9/2
5
4
4
Absorption Coefficient (cm-1)
4
1
2
G5/2 + G(1)7/2+ H(2)11/2
30
Nd3+:Y2O3 in Epoxy
25
4
2
2
2
G11/2+ K15/2 + G(1)9/2+ D(1)3/2
20
2
4
15
2
4
4
G7/2 + K13/2 + G9/2
H(2)9/2 +4F5/2
F7/2 +4S3/2
10
4
5
F9/2
F9/2
0
500
0
500
600
700
600
800
700
800
Wavelength (nm)
Wavelength (nm)
40
Polymer embedded samples yield similar spectral
features to polycrystalline ceramic sample
Absorption Coefficient (cm-1)
4
G5/2 +1G(1)7/2+2H(2)11/2
Nd3+:Y2O3 in HEMA
30
20
4
G11/2+2K15/2 +2G(1)9/2+2D(1)3/2
2
4
10
4
G7/2 +2K13/2 + 4G9/2
F3/2 + 4S3/2
H(2)9/2 + 4F5/2
4
F9/2
0
500
600
700
Wavelength (nm)
800
RE3+:Y2O3 Emissions from Nanoparticles
Nanoparticles
Epoxy embedded
1.2
F2
D0
5
F1
F4
7
F0
D0
0.0
580
600
620
640
660
680
700
580
720
600
620
4
F3/2
4
I11/2
1.0
0.8
4
F3/2
4
I9/2
0.4
4
F3/2
4
I13/2
0.2
0.0
930
1030
1130
1230
Wavelength (nm)
1330
1430
Fluorescence Intensity (Arb. Units)
Fluorescence Intensity (Arb. Units)
1.2
640
660
680
700
720
Wavelength (nm)
Wavelength (nm)
0.6
5
5
0.0
Nd3+:Y2O3
7
7
F3
D0
D0
D0
0.2
5
5
D0
0.4
5
7
D0
5
D0
0.2
0.6
7
F4
F3
7
7
7
F0
0.4
F1
0.6
0.8
D0
0.8
1.0
5
Fluorescence Intensity (Arb. Units)
7
F2
7
5
D0
1.0
5
Eu3+:Y2O3
Fluorescence Intensity (Arb. Units)
1.2
1.2
4
4
F3/2
I11/2
1.0
0.8
4
F3/2
4
I9/2
0.6
4
0.4
F3/2
4
I13/2
0.2
0.0
900
1000
1100
1200
Wavelength (nm)
1300
1400
Comparative Results of Nd3+ in polymer, ceramic,
and single crystals
Parameter
HEMAa
Epoxyb
Ceramicc
Ceramicd
Crystale
Crystalf
2(10-20cm2)
6.75
10.97
10.52
4.09
8.55
4.08
4(10-20cm2)
8.47
5.68
5.06
2.97
5.25
5.53
6(10-20cm2)
3.65
5.37
5.28
3.85
2.85
3.97
rad
0.623
0.549
0.532
0.354
0.655
0.589
0.584
0.499
0.504
0.318
-
-
93.7
90.9
94.7
89.0
-
-
fl
(ms)
(ms)
*Q(%)
*Internal radiative quantum efficiency
a,b,c Sardar et al., Polymer Internationa (2005), J. Appl Phys. (2004, 2005)
d Kumar et al., IEEE J Quant. Elect.(2006)
E Kaminskii, Laser Crystals, (1996)
f Morrison et al., J.Chem. Phys (1983)
Other RE-Doped Materials and their Potential
Applications
Transparent Nd:YAG
Ceramic
YbEr
Eu
YbEr
YbEr
Tb
Nd:YAG Single Crystal
YbTm
Yb,Er :Phosphate Glass
Inset:Pr :Phosphate Glass
Eu:Y2O3 :HEMA
Polymer
SrS:EuDy
Eu2+
Host: La2O2S
Top: 980 nm Ex (10mW)
Bottom: 320 nm Ex: Up
Eu:Y2O3 nanoparticles
(Homogeneous precipitation)
and Down Conversion
(Imaging, Display, Therapy, Sensing, Security, Lighting, etc.)
What is so Unique about RE (Nd3+) for Biomedical
Applications?
1.2
absorption
emission
1.0
Intensity
 Large Stoke’s shift (~500nm)
& strong emission
 Multi-frequency absorption &
emission
 Long fluorescence lifetimes
 Optical properties
“independent” of size
 Nontoxic
0.8
0.6
0.4
0.2
0.0
500
600
700
1000
Wavelength (nm)
1100
Imaging Application of RE Nanoparticles
Present technology: Organic Dyes and Quantum Dots
Advantages-Highly Fluorescent
Disadvantages-UV excitation causes autofluorescence, reducing S/N ratio
-Size tunability is needed for quantum dots for proper excitation
-Toxicity of the composition, Photobleaching
Color tunable Q dots
a
(a)
Confocal image of the 980 nm excited
Emissions (550 and 670 nm) from
Yb,Er:CaF2 Nanoparticles
Autofluorescence
(b)
b
Live cell (mouse fibroblast) image with
green upconversion under 980 nm Exc.
Cell autofluorescence under UV Exc.
After background
subtraction
Future technology: Rare Earth-doped Nanoparticles
Advantages-Highly Fluorescent, wide range of excitation and emission (UV-IR),
no autofluorescence, nontoxic, no size requirement, no photobleaching
Photodynamic Therapy with IR Upconversion
(IPDT)
Advantages: IR Upcoversion, 5 times penetration depth compared to
Current UV-X PDT
UTSA Physics Department- PREM
•
•
•
•
•
•
•
Advanced Engineering and Technology
(AET) Building ($82.5M; December 2009)
– Physics Department occupies the 3rd
floor (over 14,000 sq. ft. of lab space)
– $11.2M spent by UTSA to Renovate
Physics Research Laboratories
Thin Films Laboratory (AET)
– ALD, Laser Deposition
Biophotonics Research and Imaging
Laboratory (AET)
Synthesis Labs (AET)
– Nanomaterials
– Nanophotonics and Laser Materials
Terahertz Laboratory (AET)
Computational Physics Laboratories (AET)
– Access to the Texas Advanced
Computing Center (TACC at UT Austin)
Advanced Microscopy Laboratory (Science
Building)
– TEM-STEM, SEM, AFM, Raman
– Including the most advanced spherical
aberration corrected STEM (JEOL ARM
200F)
Tenure-track faculty
Total: 13; PREM: 7
6 Minority; 3 Women
2 Hispanic Women
1 African American Woman
UTSA PREM Researchers
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Dr. Jianhui Yang (2010)
Dr. Ajith Kumar (2011)
Erik Enrique
Joseph Barrios
Edward Khachatryan
Robert C. Dennis
Brian Yust
Leland Page
Kenneth Ramsey
Madhab Pokrhel
Nathan Ray
Francisco Pedraza
Devraj Sandhu
Jesse Salas
Hector Barron-Escobar
Marcus Najera
Gilberto Cassilas Garcia
Zurab Kereselidze
PREM Publications (2010-11)
Published or in Press:
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Chandra, S.*, Francis Leonard Deepak, J. B. Gruber, and D. K. Sardar, “Synthesis, Morphology, and Optical Characterization of Er3+:Y2O3”, J. Chem.
Physics C, 114, 874-880 (2010).
Burdick, G. W., J. B. Gruber, K. L. Nash, and D. K. Sardar, “Analyses of 4f11 Energy Levels and Transition Intensities Between Stark Levels of Er3+ in
Y3Al5O12”, Spectroscopy Letters: 43, 406-422 (2010).
Gruber, J. B., G. W. Burdick, S. Chandra*, and D. K. Sardar, “Analyses of the Ultraviolet Spectra of Er3+ in Er2O3 and Er3+ in Y2O3”, J. Appl. Phys., 108,
023109: 1-7 (2010).
Chandra, S.*, J. B. Gruber, G. W. Burdick, and D. K. Sardar, “Material Fabrication and Crystal-Field Analysis of the Energy Levels in Er3+ doped Er2O3
and Y2O3 Nanoparticles Suspended in Polymethyl Methacrylate”, J. Appl. Pol. Sci. (in Press) (2011).
Yang, J. and D. K. Sardar, “One-Pot Synthesis of Coral-Shaped Gold Nanostructures for Surface-Enhanced Raman Scattering”, J. Nano Res. (in Press)
(2011).
Yang, J., R. C. Dennis*, and D. K. Sardar, “Room-Temperature Synthesis of Flowerlike Ag Nanostructures Consisting of Single Ag Nanoplates”, Mater.
Res. Bull. (in Press) (2010).
B. Yust*, D. K. Sardar, and A. T. Tsin, "Phase conjugating nanomirrors: utilizing optical phase conjugation for imaging", SPIE Proceedings, Vol. 7908 (In
Press) (2011).
Francis Leonard Deepak, Rodrigo Esparza, Belsay Borges, X. Lopez-Lozano, Miguel Jose Yacaman, Rippled and Helical MoS2 Nanowire catalysts – An
aberration corrected STEM study. Catalysis Letters, In Press, 2011.
Page, L*, Maswadi, S, Glickman, RD, “Optoacoustic Spectroscopic Imaging of Radiolucent Foreign Bodies”, in Medical Imaging 2010: Ultrasonic
Imaging, Tomography, and Therapy, D'hooge, J; McAleavey, SA, Eds., Proc. SPIE, Vol. 7629, pp 7629OE-1 – 7629OE-7, 2010.
Maswadi*, S, Glickman, RD, Elliott, WR, Barsalou N,. “Nano-Lisa for In Vitro Diagnostic Applications”, in Photons Plus Ultrasound: Imaging and Sensing
2011, Oraevsky AA, Wang LV, Eds, Proc. SPIE, Vol. 7899, in Press, 2011.
Page, L*, Maswadi, S, Glickman, RD, “Identification of Radiolucent Foreign Bodies in Tissue Using Optoacoustic Spectroscopic Imaging”, in Photons Plus
Ultrasound: Imaging and Sensing 2011, Oraevsky AA, Wang LV, Eds., Proc. SPIE, Vol. 7899, in Press, 2011.
Francis Leonard Deepak, G. Casillas-Garcia*, H. Barron*, R. Esparza and M. Jose-Yacaman, New Insights into the structure of Pd-Au nanoparticles as
revealed by aberration-corrected STEM”, in Press, 2011
V. H. Romero, W. Egido, Z. Kereselidze*, C. M. Valdez, .E. Michaelides, X. G. Peralta, M. Jose-Yacaman, F. Santamaria. Neurons preferentially
internalize goldnanostars with strong and precise photothermal properties. Submitted to Nanomedicine NBM, 2011.
X. G. Peralta, “Plasmon modes for terahertz detection: Terahertz Plasmon modes in grating coupled double quantum well field effect transistors”, released
by LAP Lambert Academic Publishing (2010-08-30) - ISBN-13 : 978-3-8383-9371-1 (2010).
Wilmink, G. J., Rivest, B. D., Roth, C. C., Ibey, B. L., Payne, J. A., Cundin, L. X., Grundt, J. E., Peralta, X., Mixon, D. G. and Roach, W. P. , “In vitro
investigation of the biological effects associated with human dermal fibroblasts exposed to 2.52 THz radiation”. Lasers in Surgery and Medicine, n/a. doi:
10.1002/lsm.20960, 2011.
J. Antunez-Garcia, S. Mejia-Rosales, E. Perez-Tijerina, J. M. Montejano-Carrizales and M. Jose –Yacaman. “Coallescence and collision of gold
nanoparticles”. Materials, 4: 368-379, doi:10.3390/ma4020368, 2011.
16 Published, 4 other papers submitted, and 11 more under preparation
All Publications Acknowledge NSF-PREM Support: Grant No. DMR-0934218