Post on 22-Aug-2020
Scale-Up of Carbon Nanotube Synthesis at the Jefferson Lab
Free Electron Laser: From Research to Production
4The College of William and MaryDepartment of Applied Science
Michael W. Smith1, Kevin Jordan2, Cheol Park3, Michelle Shinn2, Brian Holloway4,
1NASA Langley Research Center
2Thomas Jefferson National Accelerator Facility
Funding by NASA AMPB, ASOMB, C&I,ONR, State of Virginia, Luna Innovations
3National Institute of Aerospace (NIA) - NASA
Why Make Carbon Nanotubes with the Jefferson Lab FEL?
Laser Ablation/Oven technique makes the “best” material, but in tabletop form is limited to small quantities (<= 200 mg/hour with a typical pulsed Nd:YAG laser apparatus)…
Jlab FEL is unique, it has:⇒ High average power (up to 10 kW)⇒ Tunable wavelength⇒ Underlying ultrafast pulse structure (sub-picosecond
pulses at 9 MHz for the current work)
…can this give a high volume stream of nanoparticulate catalyst and highly excited carbon stock for nanotube formation?
150 µm10 nsec = 10 feet
FEL
Ultr
afas
t Abl
atio
n
10-1
00 n
sec
Abl
atio
n
km’s/sec
four pulses
Desirable Nanotube Properties for Multi-functional Fiber-Reinforced Composites, (etc.)
Single wall.Long. High Quality (clean, straight, defect-free walls).Pure/Purifiable.Dispersable.Specific Chirality (conduction and sensing).Specific Diameter (bonding and intermolecular interactions)
Low “Quality” Nanotubes(bulk Chinese product)
Image Credits: Dr. Roy Crooks (Swales/NASA LaRC), Contributed via Cheol Park (NIA/NASA LaRC)
High Res SEM, 2005 FEL Raw Material
Image Courtesy: Ron Quinlan, College of William and Mary
High Res SEM, 2005 FEL Raw Material
Image Courtesy: Ron Quinlan, College of William and Mary
High Resolution TEM (2001) FEL MaterialShows Single Walls of Individual Tubes
Original Front-Pumped Chamber (2000-2001)
Vacuum chamber (1000 C, 500 torr)1” dia. Graphite/catalyst target
NanotubeFormation Vortex
Input FEL beam
Plasma plume
Argon drift flow
Schematic of First Side-Pumped Synthesis Chamber (2001, shutdown)
Chamber (1000 C, 760 torr)
Argon heater
Graphite/catalyst targetSpindle
NanotubeSprayInput FEL beam
Plasma plume
Sonic nozzle
Schematic RF-Induction Heated Side-Pumped Synthesis Chamber (2005-present)
1.
2.
5.
1. Graphite core2. Insulation3. Purge vessel4. Purge gas5. 3.5 kW RF coil6. Insulation7. Spindle8. Target w/catalyst9. Orifice plate10. Porous plug
heater11. Pyrometer port12. Input FEL beam13. Nanotube spray
3.
6.
7.8.
9.10.
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Chamber Core with Orifice Plate
7.5 kW Induction Heater with Graphite Test Block
Apparatus, Overhead View
FEL Beam Path
Chamber, Hot Zone
Target Loading
Chamber, Upstream End
Chamber, Upstream End
8/05, Rig installed in Lab 1
8/05, Rig installed in Lab 1
8/05, Opening Production Collector
8/05, Collector with 1 gram raw SWNT
8/05, Laden Collector
8/05, Cleaning Collector
8/05, Couple of grams of raw SWNT
8/05, Raw SWNTs in the jar, One Hour Exposure, Yield ~10%
4/05/06, 7.5 grams Raw Material Collected1.25 Hour Exposure, Est. Yield 50-80%
4/05/06, Used Target, 75 Minutes Elapsed Time
Fresh Target
Expended Target
SEM of Current High Yield Raw Material on Holey Carbon Substrate
…A Brief Digression on the Application of Raman Spectroscopy to the Analysis of Single Walled Carbon
Nanotubes…
High Res SEM, June 2005 Raw Material
Image Courtesy: Ron Quinlan, College of William and Mary
Laser Purification of August 2005 SWNT, 785 nm
10% power, dirty spot, 8.26.05.630_2
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50 X after 5sec 100%
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Raman spectrum from low yield raw material
Raman spectrum from modified raw material
(purified by 785 nm irradiation)
Laser Purification of August 2005 SWNT, 785 nm
10% power, dirty spot, 8.26.05.630_2
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50 X after 5sec 100%
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500 1000 1500 2000 2500 3000 Raman shift (cm-1)
G Band to D band ratio is a measure of sample purity…
this one’s pretty low, ~3:1, wantto see more like 100:1
G
D
D Band is measureof amorphous carbon
content
Laser Purification of August 2005 SWNT, 785 nm
10% power, dirty spot, 8.26.05.630_2
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Int
50 X after 5sec 100%
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500 1000 1500 2000 2500 3000 Raman shift (cm-1)
G
High Energy Band for SWNT’s hastwo peaks (not multiwall). G1 is
Around 1590 cm-1 (less for MWNT)
Laser Purification of August 2005 SWNT, 785 nm
10% power, dirty spot, 8.26.05.630_2
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50 X after 5sec 100%
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500 1000 1500 2000 2500 3000 Raman shift (cm-1)
Position of RBM (RadialBreathing Mode)
indicatesSWNT diameter
Laser Purification of August 2005 SWNT, 785 nm
10% power, dirty spot, 8.26.05.630_2
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50 X after 5sec 100%
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500 1000 1500 2000 2500 3000 Raman shift (cm-1)
Raman spectrum from low yield raw material
Raman spectrum from modified raw material
(purified by 785 nm irradiation)
Eight Position Sampling Chimneys Used for Fast Optimization Runs
Eight Position Sampling Chimneys Used for Fast Optimization Runs
G band Rises with Increasing Spin Rate at High Metal Catalyst Fraction
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12 Hz Rotation Rate
0.5 Hz Rotation Rate
Dylon Target, Ni:Co 2:2 atomic percent catalyst
G band Drops with Increasing Spin Rate at Low Metal Catalyst Fraction
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Dylon Target, Ni:Co 0.5:0.5 atomic percent catalyst
12 Hz Rotation Rate
0.5 Hz Rotation Rate
6 Hz Rotation Rate
Target Grain, Dylon vs. EDM GraphiteOptical Microscopy of Ablated Surface
Beam Track ~100 µm
1 mm 1 mm
SEM/EDS Image of Dylon/Phenolic Resin Target(carbon dark, metal catalyst is light)
Image Courtesy Jianjun Wang, College of William and Mary
SEM/EDS New, Fine-Grained Target(carbon dark, metal catalyst is light)
Image Courtesy Jianjun Wang, College of William and Mary
Raman Spectra, March 1-2, 2006
3.02.06chmn1
10
Int
3.02.06chmn1b
0 500In
t
3.2.06chmn1c
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3.02.06chmn2
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3.02.06chmn3
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3.02.06chmn4
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3.2.06chmn5
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3.2.06chmn7
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3.2.06dst_near
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3.2.06dst_far
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3.01.06tubeflake
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3.01.06tubescrapings
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March 2006, Raman Spectra, Chimneys 1,6,7
3.2.06chmn1c
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3.2.06chmn6
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Highest spin rate 18hz = 1080 RPM, loosest focus (+5.5 cm)
Lowest spin rate, tight focus
Used Target, March 06, Showing Thermal Damage
Comparison of FEL Synthesis with Commercial Methods
raw_HIPCO_3.11.05
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carbolex_rcvd_01
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Raman shift (cm-1)
HipCO (Hi pressure CO CVDw/Gas Phase Catalyst)
FEL Laser Ablation, 6 g/hr run
FEL Laser Ablation, variation
Arc Discharge, Carbolex
Comparison of FEL Synthesis with other Commercial Methods (4/5/06)
raw_HIPCO_3.11.05
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carbolex_rcvd_01
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Raman shift (cm-1)
HipCO (Hi pressure CO CVDw/Gas Phase Catalyst)
FEL Laser Ablation
FEL Laser Ablation, variation
Arc Discharge, Carbolex
Latest Comparison of FEL Synthesis with Unpurified HipCO (4/12/06)
raw_HIPCO_3.11.05
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4.12.06.prod.drker_area
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HipCO (Hi pressure CO CVDw/Gas Phase Catalyst)
FEL Laser Ablation, 2 g/hr run
FEL Laser Ablation, variation
Latest Comparison of FEL Synthesis with Unpurified HipCO (4/12/06)
raw_HIPCO_3.11.05
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4.12.06.prod.drker_area
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HipCO (Hi pressure CO CVDw/Gas Phase Catalyst)
FEL Laser Ablation
FEL Laser Ablation, variation
Variability of Radial Breathing ModesComparison of FEL with other Methods
raw_HIPCO_3.11.05
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4.5.06.prod.cu
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carbolex_rcvd_01
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Raman shift (cm-1)
HipCO (Hi pressure CO CVDw/Gas Phase Catalyst)
FEL Laser Ablation
FEL Laser Ablation, variation
Arc Discharge, Carbolex
FEL CNT RBM (tube diameter) Variations with Wavelength and Focusing Condition
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Ram
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140 160 180 200 220 240 260 280 300 Raman shift (cm-1)
1.6 µmat thresh
1.6 µmabove thresh
2.8 µmat thresh
1.6 µmat tightfocus
Engineering:Demonstrated high yield, HipCo-level-quality SWNT production at a production rate of 2-10 g/hour (10 to 50 X HipCo or Nd:YAG synthesis rates) at ~750 Waverage power, at 1.6 micron.
Developed specialized fine-grain FEL CNT target made in-house for < $10/lb.
Developed RF-heated laser oven apparatus (flow geometry, heat transfer/temperature distributions, target holder, production and sampling collectors, scanning and other remote controls, and visualization).
Physics:Found that the highest average yield is always at “incipient extinction”(the largest laser spot size before the plasma goes out.)
Found that the highest yield flakes of raw material always contain the smallest diameter tubes (the “smoking gun” pointing to ultrafast ablation effects).
Showed that RBM (tube diameter) varies with laser condition at a given wavelength as well as with wavelength.
Conclusions
Production at 750 W quasi cw is now routine, and will continue as required, but main focus will be on scale-up with:
Shorter Wavelengths and Higher Power (and more temporal stability)!
----------------
Projections?
At least 20-40 g/hour of highest grade material, ~5 times more forlesser grades (straight linear extrapolation).
“Designer” tubes with selectable diameter. (length?, chirality?)
More access to higher quality tubes with more choice regarding important properties => real progress in applications.
Future