Efficient and controlled synthesis of SWCNTs by enhanced direct ...

Efficient and controlled synthesis ofSWCNTs by enhanced direct injectionpyrolytic synthesis (eDIPS) method andtheir applicationsGuadalupe Workshop 2011April 8 th -12 th , 2011Texas USATakeshi SaitoNational Institute of Advanced IndustrialScience and Technology (AIST)

Table of Contents1. Reminding our recent work inGMW20072. Impact of reaction temperature onthe tube diameter3. Main gas-phase intermediatesresponsible for SWCNT growth(Importance of gas-phase chemistry)4. Recent research progress inseparation works

Our recent work(GMW2007)

Background:SWCNTs’ Diameters and Applications0.4nm 1.0nm 2.0nm 3.0nm 4.0nmOptoelectronics光 電 子 材 料The smaller the tube diameter is,the more efficient the fluorescence is.Semiconductive materials半 導 体 用 途The bandgap varies in inverse proportion to the diameter.All tubes would be almost metallic.Fillers and electrodes導 電 性 フィラー/ 電 極 ( 金 属 的 性 質 )Crystalinity would be importantfor the toughness.Ultra-tough carbon fiber高 強 度 炭 素 繊 維Utilizing both inside andoutside space of the tube.Adsorption materials吸 着 材 料Diameter control in these range→An enabling step for realization of SWCNT application!

Basic Facility of eDIPSSpray NozzleFeedstockH 2 +C H 2 24C 2 H 4 +H 2SprayNozzleMixerColumnMass FlowControllerMicro FeederReactionMechanismEvaporationof FeedstockDeposition ChamberCarrier Gas(Hydrogene)2 nd CarbonSource(Ethylene)Starting Materials & Typical Reaction Conditions‣ 1 st carbon source: Toluene etc.‣ 2 nd carbon source: Ethylene‣ Catalyst: Ferrocene‣ Promoter: Thiophene‣ Feedstock: HC:Ferro:Thio‣ Carrier gas: H 2 , ~7 slm including spray Close-up gas of ~2 of slm sprayInternal dia.: 260 µmexternal dia.: 510 µmDecomposition, Nucleation, andSurface ReactionSWCNTGrowthinGas-Phasee-DIPS: Enhanced Direct Injection Pyrolytic SynthesisSaito et al., J. Nanosci. Nanotech., 8 (2008) 6153-6157, Chem. Commun., (2009)3422-3424.

Diameter and chirality controllability ineDIPS Measured by NIR PL MappingDia.0.76nm0.92nm1.05nm1.17nm(7,5)Excitation Wavelength [nm](8,3)(6,5)(7,5)(7,6)(8,4)Dia.~ 0.8 nmE g ~ 1.2 eV1200ºC Ethylene 0~200sccmEthylene:0 Ethylene:150 Ethylene:200 Ethylene:25 Ethylene:50 Ethylene:100 sccmEmission Wavelength [nm]Saito et al., J. Nanosci. Nanotech., 8 (2008) 6153-6157.

Model of diameter control ineDIPS ProcessSize ofCatalystparticles1 nm2 nmFlow DirectionDecompositonofTolueneDecompositionof C 2 H 4DiameterDistribution ofSWCNTs0 nm1 nm2 nm3 nmShift of the distribution4 nm5–10nm

Start of Mass Production andFree sample providingNIKKISO Carbon Nanotube Technology•April, 2007•NIKKISO CO., LTD.NIKKISO Proprietary

Impact of reaction temperaturein eDIPS system

SEM Images of SamplesFurnace temp.1200 ºC1150 ºC1100 ºC1000 ºC3.0 m300 nm

Raman Analysis ofReaction Temp. DependenceEx. 488 nmFurnace temp.1000 ℃156.5 cm -1(1.585 nm)1100 ℃1150 ℃1200 ℃197.9 cm -1(1.253 nm)d = 248/ω RBMJorio et al., PRL 86 (2001) 1118

Optical Absorption Analysis ofReaction Temp. Dependence1.61.4Wideintensity /a.u.1.210.80.60.4Furnace temp.1000 ºC1100 ºC1150 ºC1200 ºCTube Diameter0.2narrow00 1 2 3 4 5 6energy / eVOpposite trend from ACCVD!(Chem. Phys. Lett., 387(2004)198.)

Model of diameter control ineDIPS ProcessSize ofCatalystparticles1 nm2 nmFlow DirectionDecompositonofTolueneDecompositionof C 2 H 4DiameterDistribution ofSWCNTs0 nm1 nm2 nm3 nmShift of the distribution4 nm5–10nm

Summaryof RT impactContrary to the case of ACCVD, decreasingthe reaction temperature graduallyincreases the tube diameter in eDIPS.This result supports our model of diametercontrolled synthesis, that is, the key factorfor controlling the diameter is not thenucleation (or aggregation) process ofcatalysts like in the other systems such asACCVD, but the supplied amount of carbonprecursor.

Narrow distribution samplesprepared by mix techniques♫ eDIPS Diameter Tuner ♫G-bandXω RBM = 265 cm -1ω RBM = 183 cm -1ω RBM = 148 cm -1RBMC2H4TempD-bandd = 248/ω RBM0.936 nmZ1.36 nmY1.68 nm

Chirality distributioncharacterized by OAS and PL1.00.8SemiconductorMetalPL0.6(10, 3) (11, 1)(12,0)(11,2)(7, 7)(9, 5) (8, 6)(10, 4)0.4(6, 5)(7, 4)(9, 8)(9, 6)(10, 2)(7, 6)(8, 5)(9, 4)0.20.00.8 1.0 1.2 1.4Diameter (nm)Saito et al., J. Phys. Chem. C, 114 (2010) 10077.Relative Amount(10, 6)(13, 2)(12, 4)(11, 6)(10, 8)(13, 5)(10, 9)(12,7)(11,9)(14, 6)(12, 1)(11, 3)(8, 7)(10, 5)(11, 4)(9, 7)(8, 3)(8, 4)(9, 2)(6, 6)(7, 5)

CountsCountsCountsCountsCountsDia. histogramfrom TEM obs.201000.5 1.0 1.5 2.0 2.5201000.5 1.0 1.5 2.0 2.530201000.5 1.0 1.5 2.0 2.520 D1000.5 1.0 1.5 2.0 2.520 E10ABC00.5 1.0 1.5 2.0 2.5Diameter (nm)Variation of SWCNTs’ AbsorptionEthylene20 sccm15 sccm10 sccm5 sccm0 sccmSpectrum on their DiameterAbsorption (arb. unit)10.90.80.70.60.50.40.30.20.1Optical absorption0S 11 S 22 M 11ABCDE0.5 1.5 2.5Photon Energy (eV)between 0.5 diameters and peak positions:Clear and wide correlation between tube diameters and peak positions was observed !Photon Energy energy (eV) (eV)32.521.51M 11S 22S 11Experimentally determined relationM 11 : E = 2.60 / d0mS 22 : 0.5 E 0.7 = 1.73 0.9 / 1.1 d m1.3 1.5 (1)m (nm –1 )S 1/d m(nm -1 11 : E = 0.962 / d m )Saito et al., Appl. Phys. Express, 2 (2009) 095006.,ISO/DTS 10868 , MSIN2010

Main gas-phase intermediatesand their chemistry in eDIPS

Model of diameter control inFixed ParameterseDIPS Process‣Temperature: 1200℃‣Carrier Gas : H 2DecompositonL/min of ositionDecomp-‣H 2 flow rate: 7.0‣Catalyst: Ferrocene1 st of 2 ndCarbon Carbon‣Promoter: Thiophene Source sourse‣Feedstock composition: HC:F:T = 100:4:21 nm(wt%)Size ofCatalystparticles1 nm2 nmFlow Direction‣ Feed rate = 5μL/minResidence Time= 2.27 Sec.Experimental Variables‣Carbon Sources1 st : Aromatic HCs,DiameterDistribution ofSWCNTs0 nm2 nm3 nm4 nmShift of the distribution5–10nm2 nd : C 2 H 4 and C 2 H 6

Carbon Sources with DifferentPh+”sp 3 ”Hybridized MoitiesPh+”sp 2 ”Ph+”sp”CH 3StyreneHCCH 2PhenylacetyleneTolueneC CHp-XyleneH 3CCH 3AllylbenzeneH 2C C CH 2 H3-phenyl-1-propyneEthylbenzeneC 2H 5C H 2C CHPropylbenzeneC 3H 7DivinylbenzeneHH 2C CC CH 2H:No or Negligible Yields!CVD reactions were surely affected by the molecular structure!!

Propylbenzene Styrene Allylbenzene DivinylbenzeneC 3H 7SEM and TEM images ofas-grown samplesHCCH 2CCH 2C CH 2 H H C H 2C CH 2 H×10K3.0 m3.0 m3.0 m3.0 m×100K300 nm300 nm300 nm300 nmInset scale bar: 4 nm 10nm 10nm 5nm

876543210Total carbon yield ofas-grown SWCNTsDifinition:Carbon Yield =Weight of productx Carbonaceous Percentageevaluated by TGA.Toluenep-XyleneEthylbenzenePropylbenzenePhenylacetylene3-phenyl-1-propyneAllylbenzeneDivinylbenzeneStyrenesp ≤ sp 3

Thermal Decomposition PatternsStyreneof HCs with sp 2 MoitiesC=C+ C2H2 •C C+ C2H3 •Allylbenzene+ H2C-C=C•C-C=C+HC ••+ C2H3 •DivinylbenzeneC=C- C2H3 •+ C3H5 •• •-C2H3 •C3H4 +HC3H3 •+H2C=CC=C•Benzyne

Thermal Decomposition PatternsTolueneof HCs with sp 3 MoitiesC•+ CH3 • C •of HCs with sp 3 Moitiesp-XyleneC•+ CH3 •C •+ HC+ HEthylbenzeneCC-CC-C •+ HCC •+ CH3 •PropylbenzeneC-C-C-HC-C-C •C •+ C 2 H 4C •-H+ • C2H5

Thermal Decomposition Patternsof HCs with sp MoitiesPhenylacetyleneC C•+ C2H •3-phenyl-1-propyne•CH2 C CC •+ C3H3 •Highly reactive!+ C2H •No production of SWCNTs from these species might be causedby the deactivation of catalyst surface passivated by the highlyreactive C2H radicals due to less H and smaller size

876543210Impact of C2H4 additionWITH C2H4 (5ccm)Remarkable points• Singificantenhancement insp3’s and styrene.• Detraction inproducts in othersp2’s.• No change (stillzero yield) in sp’s.Toluenep-XyleneEthylbenzenePropylbenzenePhenylacetylene3-phenyl-1-propyneAllylbenzeneDivinylbenzeneStyreneShukla and Saito et al., Chem. Commun., (2009) 3422-3424.Normalized Real Carbon Yield / mg

Roles of sp3 C2 and C1Neutral/Radical Speciessp 3 C2 Neutral SpeciesC2H6C – C fissionC – H fission2CH3sp 3 C1 RadicalC2H5sp 3 C2 RadicalC2H4sp 2 C2FeedstockToluene: Ferrocene:Thiophen = 100:4:2Flow rate = 5μL/minSecondary Carbon Source:C2H4 or C2H6

Comparison of Real Carbon Yieldon Addition of C2H4 and C2H6Same Gas Phase intermediate should be responsiblefor the growth in both casesShukla and Saito et al., Chem. Mater., 22 (2010) 6035-6043.

CHEMKIN-ResultShukla and Saito et al., Chem. Mater., 22 (2010) 6035-6043.1.40E-03C 2 H 4Mole Fraction of Species1.20E-031.00E-038.00E-046.00E-044.00E-042.00E-040.00E+00C 2 H 6C 2 H 2CH 4-0.1 0.1 0.3 0.5 0.7 0.9 1.1Downshift distance of reaction zone inside the reactor/cmImpact of SP 2 C2 Species,DominantSP 3 C1 Species,NegligibleBlack lines = C2H6Gray lines = C2H4C2H6 + H = C2H5+ H2C2H5 = C2H4 + HC2H6 = CH3 + CH32C2H3 = C3H3 + CH3

Summary Under the diluted conditions of carbonsources, SWCNTS were synthesized mainlyfrom the aromatic hydrocarbons with sp 2 -hybridized moieties. Analysis of the thermal decompositionpattern implies that C 2 H 3 and/or C 2 H 4 aresuperior gas-phase intermediatesresponsible for SWCNT growth in eDIPSsystem.

Length sorting and M/Sseparation of eDIPS-CNT

Effect of “Length”3TFT device reliability with Length ofSWCNTsSWCNTs Random networkFET channelL SDP error= P open +P short70μm40 251510lMetal:1/3L SD =50μm75M. Ishida and F. Nihey, Appl. Phys. Lett. 92, 163507 (2008).l short < l long < 1/10 L SD (ERROR < 1ppm)

Recent studies4• DNA-assisted Size ExclusionChromatography(M. Zheng, et.al., Nature Mat., 2003, 2, 338-342.)SWCNTs can be sorted as a function of retentiontime.• Length Fractionation ofSWCNTs Using Centrifugation(J. A. Fagan, et.al., Langmuir 2008, 24,13880-13889)SWCNTs can be sort at position of thecentrifugation tube.shortExcellent fractionation precision,BUT LOW-THROUGHPUT!!Long

Motivation5• Controlling length of SWCNTs is anticipated fromapplication side, such as printable electronics (CNT-ink).• Recent work of SEC is excellent in separating precision,but have a problem in processability.THIS WORKHere we propose a NEW & SIMPLE Experimentalprocess;“Multi-step cross-flow filtration”

Fractionation of Single Wall Carbon Nanotubes byLength Using Cross Flow Filtration MethodACS Nano, 4, 3606, (2010) SourceSWCNTssuspensionPore1mRetentatePumpAPermeatePore0.45mA B C DFilterBPermeatePermeatePore C0.2m DCounts35%30%25%20%15%10%5%0%DCB0.2 0.45 1Length ( m)AABCD3-steps cross-flow filtration processes with different poresizemembranes successfully separate 4 samples with theclear tendency of sorting by length (range of 100nm - 1mm)with high yield of 75%.

Problem for electronic applications•Synthesized CNTs containsSemiconducting(sc-):Metallic (m-) CNT=2:1making device performance worse.Requirements: separation of sc- & m- CNTs•High-purity (>90% sc-CNT 1) )•High-yield (for production)•Ionic-free (e.g. Na + )Enrichment of sc-CNTswithout ionic species is required1)M. A. Topinka, et al., Nano Lett. 9 (2009) 1866.NT10, Montreal, Canada2010/07/02 38

Normalized Absorbance (arb. unit)1.60.8S 22M 111 2 3 4Photon Energy (eV)•Estimated fromAreal Intensities 1)•Assumption of sc-CNT(Pristine) as 67%UpperPristineLower40% 60%sc-CNTs67% 33%95%m-CNTs5%sc-CNT is 95% in lower layer.1)Y. Miyata et al., J. Phys. Chem. C 112 (2008) 13187.NT10, Montreal, Canada2010/07/02 39

1.4 nm CNTs 1.7 nm CNTs10.8Normalized Absorbance (arb. unit)0.60.4Normalized Absorbance (arb. unit)0.80.60.4S 22 M 110.2S 22M 111 2 3 41 2 3 4Photon Energy (eV)0.2Photon Energy (eV)1.4 and 1.7 nm CNTs are also separated.NT10, Montreal, Canada2010/07/02 40

AcknowledgmentFund:This work is partially supported by the NewEnergy and Industrial Technology DevelopmentOrganization (NEDO).Contributions:I appreciate the contributions of my podocs, Dr. B.Shukla and Dr. S. Ohmori, collaborators, Dr. K. Ihara andDr. F. Nihey, technical assistant, Ms. Owada, Ms.Kobayashi, and Mr. Hashimoto.