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Nanomaterials: Synthesis and Applications.

Nanomaterials: Synthesis and Applications. Erich Walter Steuerman Group Meeting, August 25 th 2010. University of California, Irvine. Penner Group. Electrodeposition of nanowires Hydrogen gas sensing with palladium Ammonia gas sensing with silver

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Nanomaterials: Synthesis and Applications.

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  1. Nanomaterials: Synthesis and Applications. Erich Walter Steuerman Group Meeting, August 25th 2010

  2. University of California, Irvine Penner Group • Electrodeposition of nanowires • Hydrogen gas sensing with palladium • Ammonia gas sensing with silver • Giant Magnetoresistance in nickel and iron nanowires • Bio-sensor based on electrical detection of phage Columbia University Brus Group • Rayleigh scattering of carbon nanotubes • Photoelectrochemistry of thin films and nanoparticle arrays • Surface charge determination of metal nanoparticles • Organometallic synthesis of metal oxide nanoparticles and graphitic carbon Display and Graphics Business Lab Digital Signage Group • Transparent conductors • Nanoparticle-based electrodes and coatings • Flexible and rigid displays • Bi-stable display technologies • Transparent and reflective

  3. Nanoparticles Selected Topics: Nanomaterials Synthesis Nanowire-based Sensors • Organometallic synthesis of metal oxide nanoparticles and graphitic carbon • Electrochemical deposition of nanowires • Gas sensing with metal nanowires

  4. Metal-oxide nanoparticle syntheses: The goal of this project was to synthesize metal oxide nanoparticles • Low-temperature reaction • High energy precursors • Crystalline nanoparticles • Extend work synthesizing TiO2 nanoparticles Phenyl ether Oleic acid Typical metal-oxide nanoparticle syntheses: • High temperature reactions • Capping ligands 265°C Sun, S. And Zeng H., JACS2002, 124, 8204.

  5. Molecule-to-Solid Precursor Reactions "anion" precursor "cation" precursor solid state product TePEt3 TePEt3 TePEt3 TePEt3, SePEt3, SPBu3 TePEt3, SePEt3 TePEt3 TePEt3 TePEt3 TePEt3, SePEt3 Cr(dimethylpentadienyl)2 Mn(butadiene)2L Fe(COT)2 Co2(CO)8 Ni(COD)2 Pd(PEt3)4 ZnPh2 Hg CdR2 Cr2Te3 MnTe FeTe CoTe, CoSe, CoS NiTe, Ni3Se2 PdTe ZnTe HgTe CdTe, CdSe In each case the precursors act like "zerovalent" complexes, - "atoms" In each case clusters can be intercepted - 'molecular' and/or 'nano' Oxides?

  6. Metal-oxide nanoparticle syntheses:

  7. 1,3,5,7 Cyclooctatetraene C8H8

  8. Reaction Design Why Use M(COT)x? 1) It's easy to make: Ti(OBu)4 + 2 COT + AlEt3  2) "High energy" 3) Fe(COT)2 works to make tellurides 4) COT = stable ejecta 5) Low valent? Low valent enough

  9. Phosphine Chalcogenide H(P-E) kcal/mol Me3P-O 123 Me3P-S 76 Me3P-Se 49 Me3P-Te 36 Reaction Design (dft calculations) Reactivity: R3P-Te > R3P-Se > R3P-S >> R3P-O

  10. Donor-oxide H(E-O) kcal/mol Me2S-O 69 Me2Se-O 48 Me2Te-O 60 Me3N-O 60 Reaction Design recall Me3P-O: 123 kcal/mol Me3P-Te: 36 kcal/mol

  11. Ti(COT)2+ 2 OS(CH3)2 rt 120°C no ligands OPR3 ligand TiO2 rt OPR3 ligand immediate precipitation of amorphous dust sinter 4-7 nm TiO2 TiO2 anatase 15 nm TiO2 An Organometallic Synthesis of TiO2

  12. Mx(COT) y Ru(COT)(COD) Fe(COT)2 V(COT)2 W2(COT)3 W, Ru, V, and Fe…

  13. “V atom” “O atom” ligand/passivating agent Low-Temperature Organometallic Preparation of Vanadium Oxides V(COT)2 + 4 OS(CH3)2 + 4 CH3OCH2CH2OCH3 - Reaction run in toluene at 110 C - No ligand: no isolated particles 100 nm

  14. “Fe atom” “O atom” ligand/passivating agent Low-Temperature Organometallic Preparation of Iron Oxides Fe(COT)2 + 4 OS(CH3)2 + 4 CH3OCH2CH2OCH3 - crystalline particles - electron diffraction: Fe3O4 TEM: nm-size particles - Reaction run in toluene at 110 C - No ligand: no isolated particles - Previously: TiO2 HfO2 - Also W, Ru oxides…

  15. Room Temperature: Fe(COT)2 + 4 OS(CH3)2 + 4 CH3OCH2CH2OCH3 - crystalline particles 700 nm ~20 days

  16. Why is this exciting to us? How does these reactions work initially? How does changing the ligand or solvent affect the reaction? Size control with ligand concentration? Phase control with DMSO concentration? Crystallinity and phase control with ligand? Se, Te, S, N nanocrystals? Reaction Time? Reaction Temperature? Reaction on surfaces? AxByOz, etc..?

  17. One more reason : sideproducts? ~1 m TEM

  18. Scanning Electron Microscopy Nanoparticle rich area Black crystalline area

  19. SEM

  20. Sure, but is it crystalline? Electron Diffraction

  21. Carbon nanostructures Graphite Graphene • Extremely important and versatile materials • Scientifically interesting Carbon nanotube

  22. Synthesis of Graphite and Carbon Nanotubes Carbon Nanotubes -High temperature (500 - 2000°C) -Forcing conditions (Chemical Vapor Deposition, Plasma, Arc Discharge) -Flow a carbon feedstock (ethanol, acetylene, methane) over metal nanoparticles at high temperature Graphite & Graphene -Pyrolysis of organic precursors (2000°C)

  23. Synthesis of Graphite and Carbon Nanotubes 100 mg of Fe(COT)2 is dissolved in toluene Solution is brought to reflux, 110 L of DMSO is injected Reaction runs for 5 days 50 mg of brown-black powder

  24. Separation Concentrated HCl removes particles but can damage the graphite 10 - 20 mg remain after acid treatment Energy Dispersive X-Ray Analysis (EDX): Iron Oxygen Carbon EDX: Oxygen Carbon

  25. Separation Concentrated HCl removes particles but can damage the graphite 10 - 20 mg remain after acid treatment Energy Dispersive X-Ray Analysis (EDX): Iron Oxygen Carbon EDX: Oxygen Carbon

  26. Sideproducts. TEM of acid-washed sample

  27. Transmission Electron Microscopy

  28. Transmission Electron Microscopy

  29. Transmission Electron Microscopy

  30. Transmission Electron Microscopy E. Dujardin et al., Adv. Mater., 1998, 10, 611-613.

  31. Transmission Electron Microscopy

  32. Transmission Electron Microscopy

  33. Transmission Electron Microscopy

  34. High-Resolution TEM Brookhaven National Lab-Tobias Beetz, Matt Sfier

  35. High-Resolution TEM Brookhaven National Lab-Tobias Beetz, Matt Sfier

  36. High-Resolution TEM Brookhaven National Lab-Tobias Beetz, Matt Sfier

  37. High-Resolution TEM Brookhaven National Lab-Tobias Beetz, Matt Sfier

  38. High-Resolution TEM Brookhaven National Lab-Tobias Beetz, Matt Sfier

  39. High-Resolution TEM Brookhaven National Lab-Tobias Beetz, Matt Sfier

  40. High-Resolution TEM 3.4 Å

  41. Micro-Raman Spectroscopy

  42. Synthesis of Graphite and Carbon Nanotubes • Low temperature (110°C) • Air-free synthesis • Solution-phase (toluene) • Sheets and tubes of graphite A species between atomic Fe or FeOx and nanoscale FeOx is catalysing the synthesis.

  43. The Road Ahead ? 1,3,5,7 Cyclooctatetraene http://www.its.caltech.edu/~yehgroup/stm/ • Characterize catalytic center • Understand and direct the synthesis • Investigate initial reaction • Further characterization of carbon product

  44. Fe(CO)5 + 5x Trimethylamine-n-oxide + COT

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