Synthesis and Synthesis and Characterization of Rare Characterization of Rare Earth Nanomaterials and their Biological Earth Nanomaterials and their Biological

and Photonic Applicationsand Photonic Applications

Dhiraj SardarDhiraj SardarDepartment of PhysicsDepartment of Physics

University of Texas at San AntonioUniversity of Texas at San AntonioMarch 10 and 11, 2011March 10 and 11, 2011

NORTHWESTERN UNIVERSITY

NSF - PREM - MRSEC

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

Electronic Configuration (RE3+) : Incomplete inner 4fN orbital : [Xe]4fN5s25p6(N=113)

Optical Properties : Strong absorption and fluorescence : Wide range of excitation and emission (UV-VIS-IR)

Applications : Lasers, Display, Sensor, Therapy, Biomedical imaging, etc.

Energy levels of trivalent rare earths (RE3+ )

Electron charge distribution in different orbitals for RE ions showing the shielding of 4f electrons by outer 5s and 5p electrons

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)JEOL-ARM200F(0.06 nm resolution)

RESULTS

STEM imaging of the Nd3+ distribution

Nd3+:Sc2O3

Blue = Scandium , Red = OxygenBlue = Scandium , Red = Oxygen

Theoretical (Judd-Ofelt Formalism)

4 2 22

32,4,6

64 ( 1)( ) | |

3 (2 1) 9t

rad tt

e n nA J J J U J

h J

(Judd-Ofelt Model)

Radiative Quantum Efficiency:

fl rad

rad rad nr

A

A A

Arad=radiative decay rateAnr=nonradiative decay rate

1( )

nr mp ET OH imp

fl rad nr

A A A A A

A A

Radiative Process:

Major Nonradiative Processes:

1.Multiphonon relaxation (Amp)2.Energy transfer between ions (AET)3.Hydroxyl content/High frequency vibrational groups (AOH)4.Impurity (Aimp)

4I9/2

4I11/2

4I13/2

4I15/2

980nmPump

Amp

AOH

AET

AET1550nm550nm

650nm

4S3/2

4F7/2

4F9/2

Er3+

J

J

( )radA J J

Wavelength (nm)

500 600 700 800

Abs

orpt

ion

Coe

ffici

ent (

cm-1

)

0

10

20

30

40

2H(2)9/2 + 4F5/24F3/2 + 4S3/2

4F9/2

4G11/2+2K15/2 +

2G(1)9/2+2D(1)3/2

4G7/2 +2K13/2 + 4G9/2

4G5/2 +1G(1)7/2+

2H(2)11/2

Wavelength (nm)

500 600 700 800

Abs

orpt

ion

Coe

ffici

ent (

cm-1

)

0

5

10

15

20

25

30

4G7/2 +2K13/2 + 4G9/2

4G5/2 +1G(1)7/2+

2H(2)11/2

4F9/2

4F7/2 +4S3/2

2H(2)9/2 +4F5/2

4G11/2+2K15/2 +

2G(1)9/2+2D(1)3/2

Nd3+:Y2O3 in HEMA

Nd3+:Y2O3 Ceramic

Polymer embedded samples yield similar spectral features to polycrystalline ceramic sample

Wavelength (nm)

500 600 700 800

Abs

orpt

ion

Coe

ffici

ent (

cm-1

)

0

5

10

15

20

25

30

35

4G11/2+2K15/2 +

2G(1)9/2+2D(1)3/2

4G7/2 +2K13/2 + 4G9/2

4G5/2 +1G(1)7/2+

2H(2)11/2

4F9/2

4F7/2 +4S3/2

2H(2)9/2 +4F5/2

Nd3+:Y2O3 in Epoxy

Nd3+:Y2O3 Absorptions from Ceramic and Embedded in Polymers

RE3+:Y2O3 Emissions from Nanoparticles

Wavelength (nm)

580 600 620 640 660 680 700 720

Flu

ores

cenc

e In

tens

ity (

Arb

. Uni

ts)

0.0

0.2

0.4

0.6

0.8

1.0

1.2

5 D0

7 F

0

5 D0

7 F

1

5 D0

7 F 2

5 D0

7 F

3

5 D0

7 F

4

Nanoparticles Epoxy embedded

Eu3+:Y2O3

Nd3+:Y2O3

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 (ms) 0.623 0.549 0.532 0.354 0.655 0.589

fl (ms) 0.584 0.499 0.504 0.318 - -

*Q(%) 93.7 90.9 94.7 89.0 - -*Internal radiative quantum efficiencya,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:YAGCeramic

Eu:Y2O3 :HEMA Polymer

Yb,Er :Phosphate GlassInset:Pr :Phosphate Glass

Nd:YAG Single Crystal

Up and Down Conversion (Imaging, Display, Therapy, Sensing, Security, Lighting, etc.)

Eu:Y2O3 nanoparticles(Homogeneous precipitation)Host: La2O2S

Top: 980 nm Ex (10mW)Bottom: 320 nm Ex:

YbEr YbEr YbEr

YbTm SrS:EuDy

Eu Tb Eu2+

What is so Unique about RE (NdWhat is so Unique about RE (Nd3+3+) for Biomedical ) for Biomedical Applications?Applications?

Large Stoke’s shift (~500nm)& strong emission

Multi-frequency absorption & emission

Long fluorescence lifetimes Optical properties

“independent” of size Nontoxic

Wavelength (nm)

500 600 700 1000 1100

Inte

nsity

0.0

0.2

0.4

0.6

0.8

1.0

1.2absorption emission

Imaging Application of RE Nanoparticles

Present technology: Organic Dyes and Quantum DotsAdvantages-Highly FluorescentDisadvantages-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

Autofluorescence 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

Confocal image of the 980 nm excited Emissions (550 and 670 nm) from

Yb,Er:CaF2 Nanoparticles

a b

(a) Live cell (mouse fibroblast) image with green upconversion under 980 nm Exc.

(b) Cell autofluorescence under UV Exc.

Photodynamic Therapy with IR Upconversion(IPDT)

Advantages: IR Upcoversion, 5 times penetration depth compared to Current UV-X PDT

• 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)

UTSA Physics Department- PREMUTSA Physics Department- PREM

Tenure-track facultyTotal: 13; PREM: 76 Minority; 3 Women2 Hispanic Women 1 African American Woman

UTSA PREM ResearchersUTSA 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

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

PREM Publications PREM Publications (2010-11)(2010-11)