CN101451273A - Electrochemical treatment method of single wall carbon nanotube, single wall carbon nanotube and device - Google Patents

Abstract

The invention provides an electrochemical processing method for a single wall carbon nanotube (SWNT), a single wall carbon nanotube and a device thereof. The method for selectively processing the SWNT uses the SWNT as anode, exerts voltage higher than the etching starting voltage and carries out electrochemical etching on the SWNT in electrolyte.

Description

The electrochemical process for treating of Single Walled Carbon Nanotube, Single Walled Carbon Nanotube and device

Technical field

The present invention relates to the method for a kind of processing Single Walled Carbon Nanotube (SWNT), more particularly, relate to electrochemical process for treating to SWNT, the Single Walled Carbon Nanotube of handling thus and use its device.

Background technology

Carbon nanotube (CNT) has electricity, mechanics and the chemical property of many excellences as monodimension nanometer material, therefore is subjected to people's attention day by day.Along with to the deepening continuously of nano materials research, the broad prospect of application of carbon nanotube is also just constantly emerged in large numbers, and for example is used for field emitting electronic source, nano field-effect transistor, hydrogen storage material and high strength fibre etc.

Carbon nanotube can be divided into Single Walled Carbon Nanotube (SWNT) and multi-walled carbon nano-tubes (MWNT) according to the number of plies of the carbon atom that forms tube wall, and wherein multi-walled carbon nano-tubes is appreciated that to being formed by different diameter Single Walled Carbon Nanotube suit.In the research and application of reality, SWNT, the less MWNT of the number of plies have consequence owing to the performance that has is outstanding.Especially, SWNT is regarded as the material of wishing most of following nanoelectronics.

The method for preparing carbon nanotube commonly used comprises graphite arc method, chemical Vapor deposition process and laser evaporation method etc.Product by the resulting carbon nanotube of these methods generally includes metallic carbon nanotubes and the semiconductive carbon nano tube that mixes, and there is certain distribution in the diameter of these carbon nanotubes.Therefore one of prerequisite that metallicity and semiconductive carbon nano tube are dropped into practical application is exactly from the preparation product that the carbon nanotube of different conductivities is separated from one another.The separation of carbon nanotube has become one of important topic of current research thus.

In addition, though to the allotropic substance of carbon for example the electrochemical etching effect of graphite, decolorizing carbon, carbon fiber etc. carried out a large amount of research, but rarely have report for the etching effect of carbon nanotube.Though people such as Crooks have reported the etching effect (Ito of multi-walled carbon nano-tubes (MWNT), T., Sun, L., Crooks, R.M.Electrochem.Solid-State Lett.6, C4-C7 (2003)), yet the electrochemical etching of SWNT is still unknown and research that do not have this respect so far, although many study group have used electrochemical method to come covalently functionalization SWNT, for example referring to Glodsmith et al, Science 315,77-81 (2007) and Stoll et al, Chem.Phys.Lett.375,625-631 (2003) etc.

Summary of the invention

Consider the problem in the correlation technique, still have needs the treatment process of new SWNT, with more efficient, easily enrichment is had a SWNT of certain specific character.

According to a first aspect of the invention, one embodiment of the present of invention provide a kind of selectivity to handle the method for Single Walled Carbon Nanotube, wherein, use SWNT to be anode, be applied to the above voltage of etching start voltage, in electrolytic solution, SWNT is carried out electrochemical etching, thereby can purify and the SWNT of enrichment specific character this SWNT.This characteristic can be the diameter of electroconductibility or SWNT.

In one embodiment of the invention, can use SWNT membrane electrode or block type electrode as anode.

In one embodiment of the invention, can use acidity, neutrality or alkaline electrolyte, preferably use alkaline electrolyte.This electrolytic solution can be aqueous electrolyte or nonaqueous electrolytic solution.

In one embodiment of the invention, use noble electrode as negative electrode, this noble electrode can be Pt electrode, Graphite Electrodes, platinum carbon dioxide process carbon electrode, gold electrode etc.

According to a second aspect of the invention, provide a kind of Single Walled Carbon Nanotube of selecting processing through aforesaid method.

According to a third aspect of the invention we, provide a kind of carbon nano tube device, comprised the Single Walled Carbon Nanotube of selecting processing through aforesaid method.Preferably, this carbon nano tube device comprises that carbon nano-tube element comprises conducting film, field emitting electronic source, transistor, lead, electrode materials, nanoelectronic mechanical system, nanometer cantilever, quantum calculation device, photodiode, solar cell, surface conduction electron emission display device, wave filter, doser, thermally conductive material, nanometer shower nozzle, energy storage material, fuel cell, transmitter or the support of the catalyst of using carbon nanotube.

Below by accompanying drawing and one exemplary embodiment, treatment process of the present invention is described in further detail.

Description of drawings

Fig. 1 is KOH, the KCl of 0.1M and the cyclic voltammetry curve (cyclicvolatmmegram) of the HCl aqueous solution.

Fig. 2 SWNT electrode is at the typical timing ampere analytic curve of the etching processing of 0.1M KCl under 2.0V, and wherein illustration is the timing ampere analytic curve that amplifies in 0～5s scope.

Fig. 3 A is the photo of SWNT film on glass, the SWNT of arrow indication etching and the interface between the SWNT of etching not.Fig. 3 B is the NIR spectrum of SWNT before the etching and afterwards.Fig. 3 C is the electrochemical etching TEM image of SWNT afterwards.Fig. 3 D is the electrochemical etching HRTEM image of SWNT afterwards.Fig. 3 E is the Raman spectrum (633nm) of the SWNT of electrochemical etching.Fig. 3 F is before the electrochemical etching and the I-V curve of SWNT film afterwards.

Fig. 4 is the Raman spectrum (633nm) of the SWNT after 60 minutes of 1.3V etching 5,15 in the KCl of 0.1M solution.

Fig. 5 is the SWNT electrode at the KCl of 0.1M solution respectively 1.6,2.0,2.5 and the timing ampere analytic curve of the etching processing of 3.0V.

Fig. 6 be SWNT 0.1M KCl solution respectively 1.0,1.2,1.5,2.0 and the 3.0V etching after Raman spectrum (633nm).

Fig. 7 be the SWNT electrode at 3.0V respectively at KCl, the KOH of 0.1M and the timing ampere analytic curve of the etching processing in the HCl solution.

Fig. 8 is SWNT at the 2.0V Raman spectrum after the etching in KCl, the KOH of 0.1M and HCl solution respectively.

Fig. 9 be at 0.1M KCl solution before the 2.0V electrochemical etching and the XPS spectrum of SWNT afterwards.

Figure 10 illustrates three sections mechanism of the electrochemical etching of SWNT.

Figure 11 A and 11B be respectively the Raman spectrum of SWNT after the etching in the KCl of 0.1M solution (488nm, 633nm).

Figure 12 illustrates the electricity selectivity of electrochemical etching.

Embodiment

Below with reference to the accompanying drawings exemplary embodiment of the present invention is described.

The important application of SWNT comprises for example field effect transistor, hydrogen storage materials, lithium ion battery, catalyzer and electrical condenser etc.One embodiment of the present of invention provide a kind of selectivity to handle the method for Single Walled Carbon Nanotube, wherein, be anode with SWNT, apply the above voltage of etching start voltage, in electrolytic solution, SWNT is carried out electrochemical etching, thereby can purify and the SWNT of enrichment specific character this SWNT.This characteristic can be the diameter of electrical or SWNT, for example can make the metallic carbon nanotubes enrichment.In one embodiment of the invention, use the SWNT membrane electrode as anode and processed.

In the explanation in conjunction with the embodiments,, a kind of three sections mechanism have been proposed below at the electrochemical etching technology of this SWNT.In addition, in this electrochemical etching technology, the processing list of SWNT is revealed diameter selectivity and electricity selectivity, proposed an equation for this reason and understood this selectivity and control this etching technics thus.

Pending SWNT can be by preparing such as ordinary methods such as arc process, CVD method or laser pulse methods.But the present invention is not limited to the preparation method of SWNT.In addition, existing metallic carbon nanotubes among this pending SWNT also has semiconductive carbon nano tube.The SWNT that uses in an example of the present invention is (the HiPco SWNT, purity is higher than 95%, buys from U.S. Rice University) that the high pressure catalyst decomposes method by carbon monoxide produces, and wherein uses such as the Fe particle as catalyzer.

Pending SWNT can be prepared as SWNT conducting film, SWNT block materials, and material such as single SWNT, and wherein the SWNT block materials can obtain for direct growth or aftertreatment.The making of SWNT film is similar to paper Wu et al, Science 305, and 1273-1276 (2004) is described, wherein use glass or quartzy as substrate, film in air 120 ℃ of dryings 12 hours removing the molecule of absorption, and obtain uniform SWNT film subsequently.

In etching technics, use aqueous electrolyte solution, wherein be impregnated with as the pending for example SWNT film of anodic, and as negative electrode such as noble electrodes such as Pt electrode, Graphite Electrodes, platinum carbon dioxide process carbon electrode and gold electrodes.Bias voltage is applied between anode and the negative electrode.After etching technics finishes, with the SWNT film immersion after handling in distilled water to remove residue electrolytic solution, subsequently in air 120 ℃ of dryings.

With afterwards, use transmission electron microscope (TEM) (Hitachi-2010 works in 200kV), Raman spectrum (Raman), near infrared spectrum and x-ray photoelectron to check the SWNT film by spectrogram (XPS) before the etching technics.Before etching technics and afterwards, (XP-2, Ambios Technology Inc USA) check thickness to use profilometer.Use the MCP-TP06P probe to check the resistance of SWNT film by Loresta-EP MCP-T360 ohmer.Use Zahner IM6e electrochemical workstation to measure cyclic voltammetry curve and timing ampere analytic curve, wherein use the SWNT electrode as working electrode, Pt goes between as counter electrode, and Ag/Ag ⁺Electrode is as reference electrode.For current-voltage (I-V) curve of measuring the SWNT film, source and drain electrode are deposited on the SWNT film, and use probe station (MP1008, Wentworth Company, USA) and the analyzing parameters of semiconductor device (Hewlett-Packard USA) at room temperature measures the I-V curve in air.

Raman spectrum is a kind of strong means that characterize carbon nanotube, can calculate the diameter and the electroconductibility of carbon nanotube by Raman spectrum.When carrying out the Raman spectrum detection, for the reunion of getting rid of Single Walled Carbon Nanotube influence to detected result, employed all samples for example can carry out following processing in Raman test: in ethanol, carried out ultrasonication 5 minutes, then with resulting hanging drop on sheet glass and at air drying.

In the Raman spectrum, at 100～400cm ^-1Low frequency region provided one of feature backscatter mode corresponding to single-layer carbon nano-tube radially breathing pattern (Radial-Breathing Mode, RBM).The frequency of RBM pattern and the diameter of single-layer carbon nano-tube are inversely proportional to, its relation can be expressed as ω=223.75/d+6.5 (for example, with reference to Lyu, S.C.; Liu, B.C.; Lee, T.J.; Liu, Z.Y.; Yang, C.W.; Park, C.Y.; Lee, C.J., Chem.Commun.2003,734).Wherein, ω is that unit is cm ^-1The RBM frequency, d is that unit is the diameter of the single-layer carbon nano-tube of nm, and buildup effect is taken in.130～350cm ^-1The RBM frequency corresponding to the diameter of 0.6～1.8nm.And at 1586cm ^-1The 1552cm that occurs of the left side of main peak (G band) ^-1Acromion be derived from the E of graphite _2gThe division of pattern.And this acromion also is one of feature Raman scattering pattern of single-layer carbon nano-tube (for example, with reference to A.Kasuya, Y.Sasaki, Y.Saito, K.Tohji, Y.Nishina, Phys.Rev.Lett.1997,78,4434).Except these characteristic peaks, at 1320cm ^-1The peak that occurs is corresponding to the pattern by defect inducing, i.e. D band, and this is corresponding to the defective of the decolorizing carbon that contains in the sample etc.And G/D is than being the defective of measurement single-layer carbon nano-tube and the good index of purity.This G/D increases (for example, with reference to H.Kataura, Y.Kumazawa, Y.Maniwa, Y.Ohtsuka, R.Sen, S.Suzuki, Y.Achiba, Carbon 2000,38,1691) than the increase with single-layer carbon nano-tube purity.

Infrared spectra can reflect the ratio of semiconductive SWNT with respect to metallicity SWNT.

Result and discussion

Adopting the SWNT film of above-mentioned preparation is anode, is negative electrode with Pt, adopts different electrolytic solution to carry out electrochemical treatment, and resulting typical cyclic voltammetry curve is shown in Fig. 1, and its condition is: in KOH, the KCl or the HCl aqueous solution of 0.1M, and with Ag/Ag ⁺Electrode is as reference electrode.Here KOH, KCl or the HCl aqueous solution are as the representative of typical alkalescence, neutrality and acid electrolyte.Those skilled in the art can also select for example NaOH well known in the art, H for use ₂SO ₄, NaCl, LiOH, KNO ₃Or HNO ₃Etc. organic electrolytes such as inorganic electrolyte or Potassium ethanoate, sodium-acetates.Perhaps, can also select nonaqueous electrolytic solution for use, such electrolytic solution for example ionogen adopts quaternary ammonium cation and chlorine, bromine, the iodine of the tetraethyl-or the tetrabutyl or crosses negatively charged ion such as chlorate anions, and solvent adopts acetonitrile, dimethyl formamide, pyridine, dimethyl sulfoxide (DMSO) or acetone etc.

Among Fig. 1, curve 1,2 and 3 corresponds respectively to the situation that electrolytic solution is KOH, KCl or HCl.Electric current in low voltage range is little, and electric current increases suddenly during to cut-in voltage.As shown in Figure 1, the cut-in voltage difference of electric current, and be respectively 0.35V, 1.0V and 1.2V at KOH, KCl, HCl solution.

Typical timing ampere analytic curve in the etching processing is shown in Fig. 2, and wherein illustration is the timing ampere analytic curve that amplifies in 0～5s scope.SWNT film etching under the voltage at 2.0V in the KCl of the 0.1M aqueous solution.Observe four zones of the curve that is indicated as figure.In the first area (i), (＜2s) increase (shown in the illustration of Fig. 2) rapidly infers that this initial big electric current may be because for example slowly combination of capacitive discharge, surface induction current response and surperficial processing of inserting to electric current at short notice.At second area (ii), (2～1700s) maintain specific currents to electric current, can find that the etching of SWNT film betides this zone long-time, and because this film has thickness, and etching processing starts from the surface of film, so film keeps conduction in this zone, and the etching electric current is kept.In the 3rd zone (iii), electric current slowly reduces at initial portion, and reduces speed and increase gradually.At last, electric current reduces by 2 rapidly more than the order of magnitude.In the 3rd zone, etching processing has proceeded to the entail thickness of SWNT film, and because consumption and the destruction of SWNT, and the increase of resistance, the etching electric current significantly reduces.In the 4th last zone (iv), electric current keeps little value, and reduces slightly owing to the etching of remaining SWNT or decolorizing carbon.

After etching processing, find that the part of the SWNT film of immersion solution is faded and become more transparent (Fig. 3 A), therefore form tangible interface at the horizontal plane place of electrolyte solution.From NIR spectrum (Fig. 3 B), after etching processing, increase to 85% from 73% in the SWNT of 600nm film transparency, and for semi-conductor SWNT at 1400～1150cm ^-1, 620～900cm ^-1S in the scope ₁₁, S ₂₂The peak and for metal SWNT at 500～600cm ^-1Interior M ₁₁The peak all significantly reduces.Use the thickness of the SWNT film of profilometer measurement.After etching, mean thickness is reduced to about 30nm from about 90nm.Fig. 3 C shows this electrochemical etching and handles the TEM image of SWNT afterwards.Remaining SWNT still shows fascircular texture, and does not observe too many decolorizing carbon, and this shows that this electrochemical etching method has the effect of purification, can remove wherein decolorizing carbon, Nano carbon balls or as the impurity such as metallic iron of catalyst residue.From HRTEM image (Fig. 3 D), can detect the many defectives on the SWNT sidewall thus, so this etching processing can not introduce too many decolorizing carbon in sample, but destroy and dissolved the wall of SWNT.Raman spectrum has also been confirmed this etching effect.After electrochemical treatment, D band (Fig. 3 E) significantly increases, so SWNT destroyed and etching in this is handled, because the D band is owing to textural defect or the decolorizing carbon of SWNT.

In addition, measured etching electric property afterwards.Sheet resistance about 1.3 * 10 before the etching that the four point probe ohmer is measured ³Ω/sq.After the etching, sheet resistance about 9 * 10 ⁵Ω/sq has increased about 3 orders of magnitude.Current-voltage (I-V) curve shows etching significantly reducing of electric current afterwards, corresponding to the increase of sheet resistance.This is attributable to the destruction of minimizing, SWNT sidewall of SWNT quantity and functionalized.

The contriver has investigated the influence of etching time, etching voltage and electrolytic solution in electrochemical treatment of the present invention.In etching processing, there are many factors, comprise etching time, etching voltage, electrolytic solution etc.Fig. 4 shows 5,15 and 60 minutes Raman spectrum (633nm) of SWNT etching.Be accompanied by this etching processing, D band increases gradually, and the Strength Changes at the peak in the RBM district, thus show this etching be at SWNT gradually with the process of Dynamic Selection.

Etching voltage remarkably influenced etching processing.In the KCl solution that Fig. 5 shows at 0.1M 1.6,2.0,2.5 and 3.0V under the timing ampere analytic curve of etching processing.Voltage is high more, the electric current that the etching performance is big more, short more etching time and strong more etching effect, and this also can learn by the D band strength from Raman spectrum (Fig. 6).Can notice that SWNT is etched than MWNT is easier.In the KCl of 0.1M solution, when the etching voltage that applies is higher than 1.0V, can observe the tangible electrochemical etching of SWNT, and under same condition, only just carry out at the electrochemical etching that is higher than MWNT under the etching voltage of 1.7V.This is attributable to the chemical stability of carbon nanotube, because the diameter of SWNT is less than MWNT, so so energy stability is relatively poor and destroyed under low voltage easily.

Fig. 7 shows in different electrolytes the timing ampere analytic curve in the etching processing of 3.0V, and Fig. 8 shows the Raman spectrum (633nm) of SWNT after etching.In the KOH of 0.1M solution, etching effect is the most remarkable, etch rate the fastest (450s) and to the destruction maximum of SWNT, because the intensity height of D band.In the HCl of 0.1M solution, etching phase is to slowly (1100s) and show little destruction to SWNT, because the intensity of D band is low.Therefore, in the electrolytic solution with high pH value, this electrochemical etching is more effective, that is, in alkaline electrolyte than in the acid electrolyte effectively because this electrolytic solution has the OH of high density ^-

The contriver has studied the mechanism according to the electrochemical etching of SWNT of the present invention.Electrochemical method is the technology of etching material, and etching betides in the aqueous electrolysis liquid on the anodic surface usually, because active oxygen will result from the anodic surface in this electrochemical treatment, and this active oxygen can react and this material of etching with the material on the anode.

Fig. 9 shows before the etching and the XPS spectrum of SWNT afterwards.The center at the peak of 284.5eV owing to the sp of SWNT ²Carbon.The center is attributable to C-O and C=O functional group at the peak of 286.3eV and 288.2eV.After etching, the peak of C-O and C=O functional group significantly increases, and shows that SWNT is functionalized to a great extent and destroyed.Therefore we infer that the electrochemical reaction equation on the SWNT electrode is as follows:

C(SWNT)+OH ^-→C(SWNT)O+H++2e ...(1)

C(SWNT)O+2OH-→CO ₃ ^2-+2H ⁺+2e ...(2)

In order further to understand etching process, three sections following mechanism have been supposed in invention of the present invention, wherein with reference to shown in Figure 10.

(1) at first, electrochemical oxidation reactions betides the surface of SWNT, so the sidewall of SWNT and carboxylic group or other groups are covalently functionalized, and simultaneously, many defectives are formed on the sidewall.

(2) secondly, along with electrochemical oxidation reactions, the atomic reaction of increasing SWNT, and SWNT is destroyed and disintegrate subsequently, causes the formation of decolorizing carbon.In HRTEM image (Fig. 3 D), we can observe the destruction of SWNT sidewall.

(3) last, decolorizing carbon is etched and dissolves.Because decolorizing carbon also conducts electricity, and have more defectives, and activity is very strong, therefore can be etched easilier.Crooks etc. are also observing these phenomenons, and in some researchs, electrochemical oxidation is used for purifying SWNT.Therefore in TEM image (Fig. 3 C), do not observe too many decolorizing carbon.

In this process, both show the diameter selectivity according to the electrochemical etching of SWNT of the present invention and also showed electrical selectivity.In the KCl aqueous solution that Figure 11 A and Figure 11 B show respectively at 0.1M under a series of voltages the Raman spectrum of the SWNT of etching (488nm, 633nm).In the Raman spectrum of two kinds of wavelength, reduce corresponding to the major part at the peak of higher Raman displacement with minor diameter SWNT, so this etching performance diameter selectivity, the SWNT that promptly has minor diameter compares with large diameter SWNT and is easy to be etched.After the 1.0V etching, in the Raman spectrum of 488nm, corresponding to the peak of the metal SWNT of minor diameter (about 210cm ^-1) reduce, and in the Raman spectrum of 633nm, corresponding to the peak of the semi-conductor SWNT of minor diameter (about 260cm ^-1) increase, so this etching performance electricity selectivity, promptly metallicity SWNT is etched than the easier 1.0V of being etched in of semiconductive.Equally, under other voltage, the etching of SWNT is also shown similar diameter and electricity selectivity.Under the 2.0V after the etching, the content of semi-conductor and metallicity SWNT becomes 21% and 79% (drawing by the 633nm Raman spectrum) from 54% and 46% respectively in 0.1M KCl.

(diameter selectivity)

The diameter selectivity originates from the stability of SWNT, because the partial potential of SWNT is relevant with diameter.Each carbon atom (E of SWNT _c) strain energy can calculate by following formula:

E _c＝Ea ³Ω/24R ² ...(3)

Wherein E is the Young's modulus of graphite plane, and a is the interlamellar spacing of graphite, and Ω is the area of each carbon atom of SWNT, and R is the radius of SWNT.Therefore the strain energy of each carbon atom is according to R ^-2Relation increases.This shows that the more little SWNT of diameter will have bigger strain energy, so have higher partial potential.Therefore, the SWNT energy stability that diameter is little is poor, can be destroyed easily.

(electricity selectivity)

The electricity selectivity of electrochemical etching originates from the difference of the electron energy structure of SWNT.Because SWNT presents the different-energy structure corresponding to its chirality, its chirality can be with (n, so m) value representation is and exhibit metallic or semiconducting behavior.And the charge transport between SWNT and the electrolyte solution is shown in Figure 12, and relates to its energy-structure, therefore for the speed of the electrochemical reaction of the SWNT with different chiralitys and electric property with different.Therefore, etch rate k _Et:

W wherein _Red(ε) in this solution of ε local energy, occupying the number of attitude, W _SWNT(ε, V _Etching) apply etching voltage V for working as _EtchingThe time at the number of the vacant state of this SWNT of ε local energy.Therefore, etch rate overlaps relevant with the energy that does not occupy the electronic state of degeneracy in electronic state and the solution of SWNT.

Therefore, diameter and electrochemistry selectivity all exist in electrochemical etching, and two kinds of factors all may influence etching effect.Therefore, proposition can be used following Equation for Calculating etch rate k _Et:

K wherein ₀(R) for relating to the constant of pipe diameter R.k ₀(R) represent the diameter selectivity, and its value will reduce and increase along with diameter.

Represent the electricity selectivity.Therefore, diameter selectivity and electricity selectivity all are present in the electrochemical etching of SWNT.

In the electrochemical treatment of SWNT, have electrochemical etching, and the etching effect of SWNT is more effective than MWNT.This electrochemical etching be can not ignore and when SWNT is used for electrochemical applications, need to consider.From another aspect, for fear of electrochemical etching, can use the more stable MWNT or the SWNT of larger diameter, apply lower voltage, select suitable electrolytic solution.Simultaneously, electrochemical etching is for the aftertreatment of SWNT SPM needle point, attenuate SWNT film, and perhaps to remove SWNT be useful to selectivity.This discovery will be expanded the understanding to the stability of SWNT in electrochemical treatment, promote the application of SWNT in electrochemical field.

And by the Single Walled Carbon Nanotube of the invention described above embodiment method preparation, wherein the content of metallic single-wall carbon nano-tube increases, and therefore can be used for for example forming carbon nano tube transparent conducting film, field emitting electronic source, nano-electrode and lead etc.

In an alternative embodiment of the invention, use by the SWNT preparation of electrochemical treatment SWNT film as field emitting electronic source.The preparation method of this SWNT film is that the SWNT supersound process 5h in ethanolic soln with electrochemical treatment spreads out this carbon nanotube, then the ethanol volatilization is removed.Functional quality than be organic solvent for the Terpineol 350 of 95%:% and cellulosic mixed solution with dispersion after the SWNT powder mixes to obtain being used for the slurry of silk screen printing, wherein the quality of organic solvent and SWNT can be than being 3:.

Be printed on slurry on the glass substrate and form required figure by silk screen printing, carry out sintering afterwards.Next, the pipe of the SWNT behind sintering film is activated.At first polished slightly in the surface of SWNT film or corrode, the tip of SWNT is exposed; Then, can carry out ion etching, to improve its electronics generating ability to the SWNT film.In order to guarantee the electroconductibility of SWNT film, can also in the printing slurry, add silver powder.

In feds, the SWNT film is as negative electrode, and tin indium oxide (ITO) film that is coated with fluorescent material is separated for example about 0.15mm by barrier ribs as anode between negative electrode and anode.Then under the control of pilot circuit, thus between negative electrode and anode, apply voltage from SWNT film emitting electrons with display image on anode.

The method through the above-mentioned treatment S WNT of the embodiment of the invention has realized thereby the carbon nanotube of different electroconductibility has been carried out separating the metallicity SWNT that has obtained enrichment, thereby can better these metallicity SWNT be used for various application devices, conductive film for example, field emitting electronic source etc., this SWNT can also be used for other device, transistor for example, lead, electrode materials is (for example transparent, porous or gaseous diffusion electrode material), nanoelectronic mechanical system (NEMS), the nanometer cantilever, the quantum calculation device, photodiode, solar cell, the surface conduction electron emission display device, wave filter (for example high frequency or optical filter), doser, thermally conductive material, the nanometer shower nozzle, energy storage material (for example hydrogen storage material), fuel cell, transmitter (for example, gas, glucose or ionization sensor) or support of the catalyst etc.Another embodiment of the present invention relate to use above-mentioned processing carbon nanotube to prepare these devices or element.

It should be noted that at last above example is only in order to technical scheme of the present invention to be described but not limit it.Although with reference to given example the present invention is had been described in detail, those of ordinary skill in the art can make amendment to technical scheme of the present invention as required or be equal to replacement, and does not break away from the spirit and scope of technical solution of the present invention.

Claims (9)

1, a kind of selectivity is handled the method for Single Walled Carbon Nanotube, comprising:

Use described Single Walled Carbon Nanotube to be anode, be applied to the above voltage of etching start voltage, in electrolytic solution, described Single Walled Carbon Nanotube is carried out electrochemical etching.

2, according to the process of claim 1 wherein that described Single Walled Carbon Nanotube is single wall carbon nano-tube film electrode or block type electrode.

3, according to the process of claim 1 wherein that described electrolytic solution is aqueous electrolyte.

4, according to the method for claim 3, wherein, described electrolytic solution is the aqueous electrolyte of alkalescence.

5, according to the process of claim 1 wherein that described electrolytic solution is nonaqueous electrolytic solution.

6,, use noble electrode as negative electrode according to the process of claim 1 wherein.

7, a kind of Single Walled Carbon Nanotube of handling according to the method selectivity of claim 1.

8, a kind of carbon nano tube device comprises the Single Walled Carbon Nanotube of handling according to the method selectivity of claim 1.

9, carbon nano tube device according to Claim 8, wherein, described carbon nano-tube element comprises conducting film, field emitting electronic source, transistor, lead, electrode materials, nanoelectronic mechanical system, nanometer cantilever, quantum calculation device, photodiode, solar cell, surface conduction electron emission display device, wave filter, doser, thermally conductive material, nanometer shower nozzle, energy storage material, fuel cell, transmitter or the support of the catalyst of using carbon nanotube.

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