Efficient and controlled synthesis of SWCNTs by enhanced direct injection pyrolytic synthesis (edips) method and their applications

Transcription

1 Efficient and controlled synthesis of SWCNTs by enhanced direct injection pyrolytic synthesis (edips) method and their applications Guadalupe Workshop 2011 April 8 th -12 th, 2011 Texas USA Takeshi Saito National Institute of Advanced Industrial Science and Technology (AIST)

2

3 Table of Contents 1. Reminding our recent work in GMW Impact of reaction temperature on the tube diameter 3. Main gas-phase intermediates responsible for SWCNT growth (Importance of gas-phase chemistry) 4. Recent research progress in separation works

4 Our recent work (GMW2007)

5 Background: SWCNTs Diameters and Applications 0.4nm 1.0nm 2.0nm 3.0nm 4.0nm Optoelectronics 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 important for the toughness. Ultra-tough carbon fiber 高強度炭素繊維 Utilizing both inside and outside space of the tube. Adsorption materials 吸着材料 Diameter control in these range An enabling step for realization of SWCNT application!

6 Basic Facility of edips Spray Nozzle Feedstock H 2 +C H C 2 H 4 +H 2 Spray Nozzle Mixer Column Mass Flow Controller Micro Feeder Reaction Mechanism Evaporation of Feedstock Deposition Chamber Carrier Gas (Hydrogene) 2 nd Carbon Source (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 spray Internal dia.: 260 µm external dia.: 510 µm Decomposition, Nucleation, and Surface Reaction SWCNT Growth in Gas-Phase e-dips: Enhanced Direct Injection Pyrolytic Synthesis Saito et al., J. Nanosci. Nanotech., 8 (2008) , Chem. Commun., (2009)

7

8 Diameter and chirality controllability in edips Measured by NIR PL Mapping Dia. 0.76nm 0.92nm 1.05nm 1.17nm Excitation Wavelength [nm] (7,5) Dia.~ 0.8 nm Eg ~ 1.2 ev (8,3) (7,5) (7,6) (8,4) (6,5) 1200ºC Ethylene 0~200sccm Ethylene 0 Ethylene 150 Ethylene 25 Ethylene 50 Ethylene 100 sccm sccm Ethylene 200 sccm Emission Wavelength [nm] Saito et al., J. Nanosci. Nanotech., 8 (2008)

9 Model of diameter control in edips Process Size of Catalyst particles 1 nm 2 nm Flow Direction Decompositon of Toluene Decomposition of C 2 H 4 Diameter Distribution of SWCNTs 0 nm 1 nm 2 nm 3 nm Shift of the distribution 4 nm 5 10 nm

10 Start of Mass Production and Free sample providing NIKKISO Carbon Nanotube Technology April, 2007 NIKKISO CO., LTD. NIKKISO Proprietary

11 Impact of reaction temperature in edips system

12 SEM Images of Samples Furnace temp ºC 1150 ºC 1100 ºC 1000 ºC 3.0 m 300 nm

13 Raman Analysis of Reaction Temp. Dependence Ex. 488 nm Furnace temp cm -1 (1.585 nm) cm -1 (1.253 nm) d = 248/ω RBM Jorio et al., PRL 86 (2001) 1118

14 Optical Absorption Analysis of Reaction Temp. Dependence Wide intensity /a.u Furnace temp ºC 1100 ºC 1150 ºC 1200 ºC Tube Diameter 0.2 narrow energy / ev Opposite trend from ACCVD! (Chem. Phys. Lett., 387(2004)198.)

15 Model of diameter control in edips Process Size of Catalyst particles 1 nm 2 nm Flow Direction Decompositon of Toluene Decomposition of C 2 H 4 Diameter Distribution of SWCNTs 0 nm 1 nm 2 nm 3 nm Shift of the distribution 4 nm 5 10 nm

16 Summary of RT impact Contrary to the case of ACCVD, decreasing the reaction temperature gradually increases the tube diameter in edips. This result supports our model of diameter controlled synthesis, that is, the key factor for controlling the diameter is not the nucleation (or aggregation) process of catalysts like in the other systems such as ACCVD, but the supplied amount of carbon precursor.

17 Narrow distribution samples prepared by mix techniques edips Diameter Tuner G-band X ω RBM = 265 cm -1 ω RBM = 183 cm -1 ω RBM = 148 cm -1 RBM C2H4 Temp D-band d = 248/ω RBM nm Z 1.36 nm Y 1.68 nm

18 Chirality distribution characterized by OAS and PL Semiconductor Metal PL 0.6 (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) Diameter (nm) Saito et al., J. Phys. Chem. C, 114 (2010) 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)

19 Counts Counts Counts Counts Counts Dia. histogram from TEM obs D E 10 A B C Diameter (nm) Variation of SWCNTs Absorption Ethylene 20 sccm 15 sccm 10 sccm 5 sccm 0 sccm Spectrum on their Diameter Absorption (arb. unit) Optical absorption 0 S 11 S 22 M 11 A B C D E Photon 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) M 11 S 22 S 11 Experimentally determined relation M 11 : E = 2.60 / d 0 m S 22 : 0.5 E 0.7 = / 1.1 d m (1) m (nm 1 ) S 1/d m (nm : E = / d m ) Saito et al., Appl. Phys. Express, 2 (2009) , ISO/DTS 10868, MSIN2010

20 Main gas-phase intermediates and their chemistry in edips

21 Model of diameter control in Fixed Parameters edips Process Temperature: 1200 Carrier Gas : H 2 Decompositon L/min of osition Decomp- H 2 flow rate: 7.0 Catalyst: Ferrocene 1 st of 2 nd Carbon Carbon Promoter: Thiophene Source sourse Feedstock composition: HC:F:T = 100:4:2 1 nm (wt%) Size of Catalyst particles 1 nm 2 nm Flow Direction Feed rate = 5μL/min Residence Time= 2.27 Sec. Experimental Variables Carbon Sources 1 st : Aromatic HCs, Diameter Distribution of SWCNTs 0 nm 2 nm 3 nm 4 nm Shift of the distribution 5 10 nm 2 nd : C 2 H 4 and C 2 H 6

22 Carbon Sources with Different Ph+ sp 3 Hybridized Moities Ph+ sp 2 Ph+ sp CH 3 Styrene HC CH 2 Phenylacetylene Toluene C CH p-xylene H 3 C CH 3 Allylbenzene H 2 C C CH 2 H 3-phenyl-1-propyne Ethylbenzene C 2 H 5 C H 2 C CH Propylbenzene C 3 H 7 Divinylbenzene H 2 C H C C H CH 2 :No or Negligible Yields! CVD reactions were surely affected by the molecular structure!!

23 Propylbenzene Styrene Allylbenzene Divinylbenzene C 3 H 7 SEM and TEM images of as-grown samples HC CH 2 H 2 C C CH 2 H H C H 2 C C H CH 2 10K 3.0 m 3.0 m 3.0 m 3.0 m 100K 300 nm 300 nm 300 nm 300 nm Inset scale bar: 4 nm 10nm 10nm 5nm

24 Total carbon yield of as-grown SWCNTs Difinition: Carbon Yield = Weight of product x Carbonaceous Percentage evaluated by TGA. Toluene p-xylene Ethylbenzene Propylbenzene Phenylacetylene 3-phenyl-1-propyne Allylbenzene Divinylbenzene Styrene sp sp 3 << sp 2 Normalized Real Carbon Yield / mg

25 Thermal Decomposition Patterns Styrene of HCs with sp 2 Moities C=C + C2H2 C C + C2H3 Allylbenzene + H2 C-C=C C-C=C +H C + C2H3 Divinylbenzene C=C - C2H3 + C3H5 -C2H3 C3H4 +H C3H3 +H2 C=C C=C Benzyne

26 Thermal Decomposition Patterns Toluene of HCs with sp 3 Moities C + CH3 C of HCs with sp 3 Moities p-xylene C + CH3 C + H C + H Ethylbenzene C C-C C-C + H C C + CH3 Propylbenzene C-C-C -H C-C-C C + C 2 H 4 C -H + C2H5

27 Thermal Decomposition Patterns of HCs with sp Moities Phenylacetylene C C + C2H 3-phenyl-1-propyne CH2 C C C + C3H3 Highly reactive! + C2H No production of SWCNTs from these species might be caused by the deactivation of catalyst surface passivated by the highly reactive C2H radicals due to less H and smaller size

28 Impact of C2H4 addition WITH C2H4 (5ccm) Remarkable points Singificant enhancement in sp3 s and styrene. Detraction in products in other sp2 s. No change (still zero yield) in sp s. Toluene p-xylene Ethylbenzene Propylbenzene Phenylacetylene 3-phenyl-1-propyne Allylbenzene Divinylbenzene Styrene Shukla and Saito et al., Chem. Commun., (2009) Normalized Real Carbon Yield / mg

29 Roles of sp3 C2 and C1 Neutral/Radical Species sp 3 C2 Neutral Species C2H6 C C fission C H fission 2CH3 sp 3 C1 Radical C2H5 sp 3 C2 Radical C2H4 sp 2 C2 Feedstock Toluene: Ferrocene:Thiophen = 100:4:2 Flow rate = 5μL/min Secondary Carbon Source: C2H4 or C2H6

30 Comparison of Real Carbon Yield on Addition of C2H4 and C2H6 Same Gas Phase intermediate should be responsible for the growth in both cases Shukla and Saito et al., Chem. Mater., 22 (2010)

31 CHEMKIN-Result Shukla and Saito et al., Chem. Mater., 22 (2010) E-03 C 2 H E-03 C 2 H 2 Mole Fraction of Species 1.00E E E E E E+00 C 2 H 6 CH Downshift distance of reaction zone inside the reactor/cm Impact of SP 2 C2 Species,Dominant SP 3 C1 Species,Negligible Black lines = C2H6 Gray lines = C2H4 C2H6 + H = C2H5+ H2 C2H5 = C2H4 + H C2H6 = CH3 + CH3 2C2H3 = C3H3 + CH3

32 Summary Under the diluted conditions of carbon sources, SWCNTS were synthesized mainly from the aromatic hydrocarbons with sp 2 - hybridized moieties. Analysis of the thermal decomposition pattern implies that C 2 H 3 and/or C 2 H 4 are superior gas-phase intermediates responsible for SWCNT growth in edips system.

33 Length sorting and M/S separation of edips-cnt

34 Effect of Length 3 TFT device reliability with Length of SWCNTs SWCNTs Random network FET channel L SD P error = P open +P short 70μm l Metal:1/3 L SD =50μm 7 5 M. Ishida and F. Nihey, Appl. Phys. Lett. 92, (2008). l short < l long < 1/10 L SD (ERROR < 1ppm)

35 Recent studies 4 DNA-assisted Size Exclusion Chromatography (M. Zheng, et.al., Nature Mat., 2003, 2, ) SWCNTs can be sorted as a function of retention time. Length Fractionation of SWCNTs Using Centrifugation (J. A. Fagan, et.al., Langmuir 2008, 24, ) SWCNTs can be sort at position of the centrifugation tube. short Excellent fractionation precision, BUT LOW-THROUGHPUT!! Long

36 Motivation 5 Controlling length of SWCNTs is anticipated from application side, such as printable electronics (CNT-ink). Recent work of SEC is excellent in separating precision, but have a problem in processability. THIS WORK Here we propose a NEW & SIMPLE Experimental process; Multi-step cross-flow filtration

37 Fractionation of Single Wall Carbon Nanotubes by Length Using Cross Flow Filtration Method ACS Nano, 4, 3606, (2010) <IF:7.5> Source SWCNTs suspension Pore 1 m Retentate Pump A Permeate Pore 0.45 m A B C D Filter B Permeate Permeate Pore C 0.2 m D Counts 35% 30% 25% 20% 15% 10% 5% 0% D C B Length ( m) A A B C D 3-steps cross-flow filtration processes with different poresize membranes successfully separate 4 samples with the clear tendency of sorting by length (range of 100nm - 1mm) with high yield of 75%.

38 Problem for electronic applications Synthesized CNTs contains Semiconducting(sc-):Metallic (m-) CNT=2:1 making 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-cnts without ionic species is required 1) M. A. Topinka, et al., Nano Lett. 9 (2009) NT10, Montreal, Canada 2010/07/02 38

39 Normalized Absorbance (arb. unit) S 22 M Photon Energy (ev) Estimated from Areal Intensities 1) Assumption of sc-cnt (Pristine) as 67% Upper Pristine Lower 40% 60% sc-cnts 67% 33% 95% m-cnts 5% sc-cnt is 95% in lower layer. 1) Y. Miyata et al., J. Phys. Chem. C 112 (2008) NT10, Montreal, Canada 2010/07/02 39

40 1.4 nm CNTs 1.7 nm CNTs Normalized Absorbance (arb. unit) S 22 M 11 Normalized Absorbance (arb. unit) S 22 M Photon Energy (ev) Photon Energy (ev) 1.4 and 1.7 nm CNTs are also separated. NT10, Montreal, Canada 2010/07/02 40

41 Acknowledgment Fund: This work is partially supported by the New Energy and Industrial Technology Development Organization (NEDO). Contributions: I appreciate the contributions of my podocs, Dr. B. Shukla and Dr. S. Ohmori, collaborators, Dr. K. Ihara and Dr. F. Nihey, technical assistant, Ms. Owada, Ms. Kobayashi, and Mr. Hashimoto.

42