Extent of Tin Doping Influences Nano Indium Oxides Aggregation - - PowerPoint PPT Presentation

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Extent of Tin Doping Influences Nano Indium Oxides Aggregation - - PowerPoint PPT Presentation

Oct 06, 2023 147 likes •385 views

Extent of Tin Doping Influences Nano Indium Oxides Aggregation Behavior in Aqueous Systems Nirupam Aich, Dipesh Das, and Navid B Saleh Civil and Environmental Engineering University of South Carolina, Columbia, SC Courtesy: Prof. Peter P.

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SLIDE 1

Extent of Tin Doping Influences Nano Indium Oxide’s Aggregation Behavior in Aqueous Systems

Nirupam Aich, Dipesh Das, and Navid B Saleh Civil and Environmental Engineering University of South Carolina, Columbia, SC

Courtesy: Prof. Peter P. Edwards, Oxford

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SLIDE 2

Outline

  • Metallic Nanomaterials
  • Bimetals (Indium Tin Oxide)
  • Environmental Relevance
  • Objectives
  • Experimental Overview
  • Preliminary Results
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SLIDE 3

Metallic Nanoparticles

  • Noble metals - Ag, Au, Pt, Pd, Ru, Rh, etc.
  • Lanthanides - La, Sc, Gd, etc
  • Quantum dots (CdSe, CdTe, etc)
  • Metal oxide NPs (ZnO, TiO2, SiO2, Fe3O4, CuO,

In2O3, SnO2,etc)

  • ligand-based metallic compounds (ferrocene)

Coated-metals Doped Metals Singular Multiple

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SLIDE 4

Usage

Takuya Tsuzuki, International Journal of Nanotechnology, 6 (2009) 567

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SLIDE 5

Environmental Implications and NM Properties

Aggregation Deposition Transformation Toxicity Shape Size Crystallinity Surface chemistry Electronic Bandgap

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SLIDE 6

Toxicity mechanism ROS generation Oxidative damage

Inspirational Work

Bandgap Energy and Cellular Toxicity Potential

Nel et al. 2012, ACS Nano

  • 4.12 to -4.84 eV

In2O3 SnO2 Bandgap can be used as a predictive tool for measuring toxic potential of metal oxides

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SLIDE 7

Indium Tin Oxide (ITO)

  • Solid solution of In2O3 and SnO2
  • Typically 10% tin oxide is doped

in Indium oxide

  • Two major properties

– High electrical conductivity – Excellent transparent properties

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SLIDE 8

ITO Applications

  • More than 95% liquid crystal

display

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SLIDE 9

ITO Applications

  • More than 95% liquid crystal

display

  • Electronic inks
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SLIDE 10

ITO Applications

  • More than 95% liquid crystal

display

  • electronic inks
  • Solar cells and photovoltaics
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SLIDE 11

ITO Applications

  • More than 95% liquid crystal

display

  • electronic inks
  • Solar cells and photovoltaics
  • electromagnetic shielding

devices

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SLIDE 12

ITO Applications

  • More than 95% liquid crystal

display

  • electronic inks
  • Solar cells and photovoltaics
  • electromagnetic shielding

devices,

  • Gas sensors

http://npol.postech.ac.kr/Research/Nanostructure.htm

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SLIDE 13

ITO Applications

  • More than 95% liquid crystal

display

  • electronic inks
  • Solar cells and photovoltaics
  • electromagnetic shielding

devices,

  • gas sensors,
  • Photocatalysts for

environmental remediation

Yumoto, H.; Inoue, T.; Li, S. J.; Sako, T.; Nishiyama, K., Application of ITO films to

  • photocatalysis. Thin Solid Films 1999, 345, (1), 38-41.
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SLIDE 14

Indium Tin Oxide (ITO) Bandgap – Probable Toxicity

  • Change in crystalline structure due to

Tin doping

  • Defects are introduced
  • Band gap change occurs
  • Ec of Indium oxide -3.63 eV
  • Ec of ITO -4.10 eV
  • Chances of overlap of Ec with the

cellular toxic potential is increased

Margalith et al, Indium tin oxide contacts to gallium nitride optoelectronic devices. Applied Physics Letters 1999, 74, (26), 3930-3932

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SLIDE 15

Biological Effects of ITO

  • Toxicity of macroscale ITO - Reports of human fatality

– Inhalation of particulate ITO – Pneumothorax and Pulmonary fibriosis – Chronic pulmonary and carcinogenic effects

  • Nano-scale ITO also demonstrates fetal malformations

and eco-toxicity

  • ROS generation is evidenced – but mechanism is not

known

1. Homma et al 2005. Pulmonary fibrosis in an individual occupationally exposed to inhaled indium-tin oxide. Eur. Resp. J. 2. Tanaka et al 2012, Pulmonary Toxicity of Indium Tin Oxide and Copper Indium Gallium Diselenide. In Materials Research Society San Francisco, CA, 2012; Vol. 1469, p 12 3. Tanaka et al 2010 Review of pulmonary toxicity of indium compounds to animals and humans. Thin Solid Films. 4. Cummings et al 2012, Indium Lung Disease. Chest 141, (6), 1512-1521. 5. Hamaguchi et al 2008, Exposure to hardly soluble indium compounds in ITO production and recycling plants is a new risk for interstitial lung damage. Occup. Environ. Med. 65, (1), 51-55. 6. Lison et al 2010, Pulmonary Alveolar Proteinosis in Workers at an Indium Processing Facility. American Journal of Respiratory and Critical Care Medicine, 182, (4), 578-578.

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SLIDE 16

Objective

  • To determine and compare the aggregation kinetics
  • f nanoscale tin-doped and undoped indium oxide

under relevant environmental conditions.

Hypothesis

  • Nano-Indium oxide (In2O3) when doped with

tin (Sn) will demonstrate altered aggregation behavior

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SLIDE 17

Methods and Variables

  • Sonication filtration
  • NaCl was used as background electrolyte
  • Transmission electron microscopy (TEM) for morphology
  • X-ray diffraction spectrometer (XRD) for crystallinity of

ITO

  • Electron dispersive spectroscopy (X-ray) for composition
  • Zeta potential measurements for surface charge
  • Time resolved dynamic light scattering (TRDLS) was used

for measuring aggregation

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SLIDE 18

HRTEM

nITO nIO

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SLIDE 19

XRD ITO EDX

10 20 30 40 50 60 70 80 90 100

Intensity (a.u.)

2 

(a)

  • No signature peaks for tin
  • Tin is incorporated substitutionally

into indium oxide lattice.

  • 30.54°, 35.4°, 59.98°, and 60.8°; which

represent dominance of (222), (400), (440), and (110) lattice planes for IO Indium (at 3.3 keV) - 88.1% Tin (at 3.5 keV) - 8.8% Oxygen (at 0.5 keV) - 3.0±0.5%

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SLIDE 20

Aggregation Kinetics

10

  • 2

10

  • 1

0.1 1

nITO nIO

Attachment Efficiency, 

NaCl Concentration, M

Both nIO and nITO are highly stable in aqueous suspension nIO is relatively more stable than nITO

CCC nITO 180 mM NaCl nIO 280 mM NaCl

Preliminary size 65-70 nm Aggregated size 120-140 nm

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SLIDE 21

Zeta Potential

  • 10
  • 20
  • 30
  • 40
  • 50

0.05 0.03 0.01

potential, mV

NaCl Concentration, M

nITO nIO

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SLIDE 22

Summary

  • Nanoscale ITO are environmentally relevant and will

likely pose significant environmental risk

  • Both doped and undoped indium oxide showed

enhanced aqueous stability

  • Tin doping reduces stability of the indium oxide
  • Likely cause may reside on the van der Waals

interaction

  • Systematic studies are necessary to better

understand fate, transport, transformation, and toxicity

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SLIDE 23
  • Dr. Navid Saleh

Dr Tom Vogt, University of South Carolina Dr Eirin Sullivan, Illinoi State University

  • Dr. Haijun Qian, Clemson University

Jaime Plazas-Tutle Nabiul Afrooz Dipesh Das

SPARC Graduate Research Fellowship Office of the Vice President for Research University of South Carolina

ACKNOWLEDGEMENT