TWI407092B - Raman scattering substrate and detection system having the same - Google Patents

Abstract

The invention relates to a raman scattering substrate. The raman scattering substrate includes a carbon nanotube composite film. The carbon nanotube composite film includes at least one carbon nanotube film and a plurality of metal partials. The carbon nanotube film includes a plurality of carbon nanotubes. The metal partials are disposed on the surface of the carbon nanotubes. The invention also relates a raman detecting system including the raman scattering substrate.

Description

Raman scattering substrate and detection system having the same

The present invention relates to a Raman scattering substrate and a detection system having the same.

In 1928, the Indian physicist CVRaman first discovered the phenomenon that the frequency of scattered light transmitted by monochromatic light after passing through a carbon tetrachloride liquid. Later, this phenomenon was called the Raman effect. The scattered light after the frequency change is generated is a Raman spectrum. Raman spectroscopy can obtain information about the vibration mode of a molecule or a functional group, called a "fingerprint spectrum" of a molecule, which provides detailed structural information of the molecule, such as the type, strength, angle, and conformational change of the chemical bond. However, the ordinary Raman scattering signal has low intensity, and it is difficult to directly detect the sample molecules until Fleischman et al. adsorbed pyridine on the rough surface of the silver electrode in 1974 to obtain a pyridine-enhanced Raman scattering signal. The Surface-enhanced Raman Scattering (SERS) effect refers to the phenomenon that the Raman scattering signal is enhanced by molecules adsorbed on the rough surface of a Raman scattering substrate such as a silver electrode. Surface-enhanced Raman scattering can be used to study the surface adsorption of molecular species, the identification of molecules on the surface orientation and surface reactions.

Preparation of stable, high enhancement factor Raman scattering substrate system for surface enhanced Raman An important basis for the scattering effect. Conventional Raman scattering substrates are mainly formed by forming a plurality of metal particles on the surface of a planar substrate, and methods for forming metal particles on the planar substrate include electrochemistry, evaporation, sputtering, and the like. A method for preparing a Raman scattering substrate, which is prepared by an electrochemical method, is described in Chinese Patent Application No. CN101294904A, which is filed on Jun. 5, 2008, and issued on October 29, 2008. The silver sol is disposed on a substrate to form a Raman scattering substrate. The Raman scattering substrate prepared by this method is difficult to make the metal particles densely arranged due to the easy aggregation of the metal particles, so that it is difficult to obtain a highly sensitive Raman scattering substrate.

In view of the above, it is necessary to provide a Raman scattering substrate in which metal particles can be densely arranged and a detection system having the Raman scattering substrate.

A Raman scattering substrate comprising a carbon nanotube composite membrane. The carbon nanotube composite membrane comprises at least one carbon nanotube membrane and a plurality of metal particles. The carbon nanotube film comprises a plurality of uniformly distributed carbon nanotubes, and the plurality of metal particles are disposed on the surface of the plurality of carbon nanotubes.

A Raman scattering substrate comprising a carbon nanotube composite membrane. The carbon nanotube composite membrane comprises a film-like structure formed by laminating two layers of carbon nanotube membranes. A buffer layer is disposed on the surface of the film structure, and the plurality of metal particles are disposed on the surface of the buffer layer facing away from the film structure. The carbon nanotube membrane includes a plurality of carbon nanotubes that are substantially parallel to each other and substantially parallel to the surface of the carbon nanotube membrane.

A Raman detection system includes a transmitting module, a Raman scattering substrate, and a receiving module. The transmitting module is configured to emit a light beam to the Raman scattering substrate . The Raman scattering substrate is used to scatter the light beam emitted by the transmitting module. The receiving module is configured to collect scattered light scattered from the Raman scattering substrate to form a Raman spectral feature map. The Raman scattering substrate comprises a carbon nanotube composite membrane. The carbon nanotube composite membrane comprises at least one carbon nanotube membrane and a plurality of metal particles. The carbon nanotube film comprises a plurality of uniformly distributed carbon nanotubes, and the plurality of metal particles are disposed on the surface of the plurality of carbon nanotubes.

Compared to the prior art, the Raman scattering substrate comprises a carbon nanotube composite membrane comprising a plurality of carbon nanotubes having a smaller size and a larger specific surface area. Therefore, the metal can be densely arranged on the surface of the carbon nanotube composite film with a small particle diameter. Thereby, the Raman scattering substrate has better stability and sensitivity.

100, 200, 300‧‧‧ inspection systems

110, 210, 310‧‧‧ launch module

120, 220, 320‧‧‧ Raman scattering substrate

121‧‧‧Support structure

122, 222, 322‧‧‧ nano carbon tube composite film

130, 230, 330‧‧‧ receiving modules

221‧‧‧Frame

321‧‧‧Base

1 is a schematic view showing the structure of a detection system using a Raman scattering substrate according to a first embodiment of the present invention.

2 is a scanning electron micrograph of a carbon nanotube flocculation film in the Raman scattering substrate of FIG.

3 is a scanning electron micrograph of a carbon nanotube rolled film in the Raman scattering substrate of FIG.

Figure 4 is a scanning electron micrograph of the carbon nanotube film in the Raman scattering substrate of Figure 1.

Figure 5 is a transmission electron micrograph of the carbon nanotube composite membrane in the Raman scattering substrate of Figure 1.

6 is a carbon nanotube composite film formed by a carbon nanotube and a metal particle in a Raman scattering substrate of FIG. 1 and a carbon nanotube film formed by a carbon nanotube film; the sample to be tested is 2.5×10 ⁻³ mol per Raman spectral characteristics obtained when the aqueous solution of pyridine is ascended.

Figure 7 is a diagram showing the carbon nanotube film formed by carbon nanotubes and metal particles in the Raman scattering substrate of Figure 1 and the carbon nanotube film formed by the carbon nanotubes. The sample to be tested is 10 ^-6 moles per liter. Raman spectral characteristics obtained when rhodamine ethanol solution.

Figure 8 is a block diagram showing the structure of a detection system using a Raman scattering substrate in accordance with a second embodiment of the present invention.

Figure 9 is a transmission electron micrograph of the carbon nanotube composite membrane in the Raman scattering substrate of Figure 8.

10 is a carbon nanotube composite film formed by a carbon nanotube, a buffer layer, and a metal particle in a Raman scattering substrate of FIG. 8 and a carbon nanotube film formed by a carbon nanotube film. The sample to be tested is 2.5×10 ⁻ Raman spectral characteristics obtained when ³ moles of pyridine aqueous solution per liter.

11 is a 10-20 ^m mole of a sample of a carbon nanotube composite film formed by a carbon nanotube, a buffer layer, and a metal particle in a Raman scattering substrate of FIG. 8 and a carbon nanotube film formed by a carbon nanotube. Raman spectral characteristics obtained per liter of rhodamine ethanol solution.

12 is a composite of a carbon nanotube composite film formed of a carbon nanotube, a buffer layer and a metal particle in the Raman scattering substrate of FIG. 8, and a carbon nanotube formed by a carbon nanotube, a buffer layer and a metal particle in FIG. The film and the carbon nanotube film formed by the carbon nanotubes are used to detect a Raman spectral characteristic map obtained when the sample to be tested is 10 ^-6 moles per liter of rhodamine ethanol solution.

Figure 13 is a block diagram showing the structure of a detection system using a Raman scattering substrate in accordance with a third embodiment of the present invention.

Figure 14 is a schematic enlarged view showing a portion of the Raman scattering substrate of Figure 13.

15 is a view showing a sample of a carbon nanotube film formed by a multi-walled carbon nanotube and a metal particle in a Raman scattering substrate of FIG. 13 and a carbon nanotube film formed by a multi-walled carbon nanotube; Raman spectral characteristics obtained when ^-6 moles per liter of rhodamine ethanol solution.

Figure 16 is a diagram showing a nano-carbon nanotube composite film formed of a single-walled carbon nanotube, a 13 nm to 17 nm metal particle in the Raman scattering substrate of Fig. 13, and a single-walled nanoparticle in the Raman scattering substrate of Fig. 13. The carbon nanotubes, the nanocarbon tube composite film formed by 28 nm to 32 nm metal particles, and the carbon nanotube film formed by the single-walled carbon nanotubes are 10 to ⁶ moles per liter of rhodamine. Raman spectral characteristics obtained in ethanol solution.

The invention will be further described in detail below with reference to the accompanying drawings.

A detection system 100 includes a transmitting module 110, a Raman scattering substrate 120, and a receiving module 130.

The transmitting module 110 is configured to emit a light beam to the Raman scattering substrate 120 to facilitate the Raman scattering substrate 120 to form scattered light. Specifically, the light beam is irradiated The spot area of the surface of the Raman scattering substrate 120 is less than 2 square microns. The beam is a strong source with a small bandwidth and a fixed frequency, such as an argon ion laser. Preferably, the wavelength of the beam is between 450.0 nm and 514.5 nm. In this embodiment, the wavelength of the light beam is 514.5 nanometers of green light, and the green light of 514.5 nanometers has a larger scattered light intensity at the same power than the light of other wavelengths.

The Raman scattering substrate 120 is configured to carry a sample to be tested, and scatter the light beam emitted by the transmitting module 110 to form scattered light having information about the molecular structure of the sample to be tested. When the light beam is emitted on the Raman scattering substrate 120, the light beam will be irradiated to the sample molecules to be tested adsorbed by the Raman scattering substrate 120, and the photons in the light beam collide with the sample molecules to be tested. The photons collide with the molecules of the sample to be tested, and the momentum changes, thereby changing the direction of the photons and scattering to the square. When some photons collide, they also exchange energy with the molecules of the sample to be tested, changing the energy or frequency of the photons, so that the photons have to be tested. Sample molecular structure information. That is, after the beam collides with the sample molecule to be tested adsorbed on the Raman scattering substrate 120, scattered light having information about the molecular structure of the sample to be tested is formed. The sample to be tested may be a solid sample (such as a sample powder, a solid particle to which a sample is adsorbed, etc.) and a liquid sample (such as a droplet of an internally dissolved sample component, a molten sample, etc.). The sample to be tested is in direct contact with the Raman scattering substrate 120 at the time of detection.

The Raman scattering substrate 120 includes a support structure 121 and a carbon nanotube composite film 122.

The support structure 121 is used to fix or support the carbon nanotube composite film 122. Specifically, the support structure 121 may be a glass substrate, a transparent plastic substrate, a grid or a frame. When the support structure 121 is a grid or a frame, the carbon nanotubes are complex The film 122 can be at least partially suspended by the support structure 121. At this time, the suspended area of the carbon nanotube composite film 122 should be greater than 2 square micrometers, that is, larger than the spot area of the light beam, and the light beam is irradiated to the carbon nanotube. The suspended portion of the composite film 122. When the support structure 121 is a glass substrate or a transparent plastic substrate, the carbon nanotube composite film 122 is attached to the surface of the support structure 121. At this time, the support structure 121 should have a good light transmittance. In this embodiment, the support structure 121 is a frame, and the frame is fixed around the carbon nanotube composite film 122 to fix the carbon nanotube composite film 122, and the carbon nanotube composite film 122 is suspended. The carbon nanotube composite film 122 is at least partially suspended or disposed on a surface of the support structure 121 having a high transmittance, and the photons that are not scattered by the light beam irradiated into the carbon nanotube composite film 122 are transmitted as far as possible. In order to prevent this part of the photons from being reflected and then irradiated onto the carbon nanotubes in the carbon nanotube composite film 122, scattered light is generated, which will interfere with the scattered light of the molecular structure information of the sample to be tested. This is not conducive to the detection of the sample to be tested by the Raman detection system 100.

The carbon nanotube composite membrane 122 includes at least one carbon nanotube membrane and a plurality of metal particles disposed on the surface of the carbon nanotube membrane, the carbon nanotube membrane comprising a plurality of uniformly distributed carbon nanotubes. Preferably, at least one metal particle is disposed on the surface of each carbon nanotube. In this embodiment, the carbon nanotube film is a self-supporting structure, and the so-called "self-supporting" means that the carbon nanotube film can maintain its own specific shape without being disposed on a surface of a substrate.

Referring to FIG. 2, the carbon nanotube film may be a carbon nanotube flocculation film formed by intertwining the plurality of carbon nanotubes, and the flocculation film is isotropic. The carbon nanotube The thickness of the flocculated membrane is between 0.5 nm and 100 μm and has a complex pore diameter of between 1 nm and 500 nm. In the carbon nanotube flocculation film, the intertwined carbon nanotubes are attracted to each other by van der Waals force to form a self-supporting carbon nanotube film.

The carbon nanotube film may also be a carbon nanotube rolled film formed by arranging the plurality of carbon nanotubes in a preferred orientation in one direction or in a plurality of directions, and the adjacent carbon nanotubes are combined by van der Waals force. The thickness of the carbon nanotube rolled film is between 0.5 nm and 100 μm and the gap between adjacent carbon nanotubes is between 1 nm and 500 nm. The carbon nanotube rolled film can be obtained by extruding the carbon nanotube array in a direction perpendicular to the substrate grown by the carbon nanotube array in a planar indenter, and the carbon nanotube is laminated in the film. The carbon nanotube is isotropic; referring to FIG. 3, the carbon nanotube rolled film can also be obtained by rolling the carbon nanotube array in a fixed direction by a roller-shaped indenter. The carbon nanotubes in the carbon nanotube rolled film are preferentially oriented in the fixed direction; the carbon nanotube rolled film can also be obtained by rolling the above-mentioned carbon nanotube array in different directions by a roller-shaped indenter. At this time, the carbon nanotubes in the carbon nanotube rolled film are preferentially oriented in different directions.

Referring to FIG. 4, the carbon nanotube film may further be a carbon nanotube film formed by the plurality of carbon nanotubes being substantially parallel to each other and substantially parallel to the surface of the carbon nanotube film. Further, the plurality The carbon nanotubes are attracted to each other by Van der Waals forces and are connected end to end and arranged in the same direction. The carbon nanotube film is a self-supporting carbon nanotube film obtained by pulling from a carbon nanotube array. The thickness of the carbon nanotube film is between 0.5 nm and 100 μm and the gap between adjacent carbon nanotubes is between 1 nm and 500 nm.

When the carbon nanotube composite film 122 includes a plurality of carbon nanotube film, the plurality of carbon nanotube films are laminated to form a layered structure. The thickness of the layered structure is not limited, and the adjacent carbon nanotube film is bonded by van der Waals force. Preferably, the layered structure comprises a layer of carbon nanotube film of less than or equal to 10 layers, so that the number of carbon nanotubes per unit area is small, so that the Raman light intensity of the carbon nanotube itself is maintained. In a smaller range, the Raman peak intensity of the carbon nanotubes in the Raman spectrum is reduced. The carbon nanotubes in the adjacent carbon nanotube film in the layered structure have an intersection angle α between the α and the α is greater than 0 degrees and less than or equal to 90 degrees. When the carbon nanotubes in the adjacent carbon nanotube film have an intersection angle α, the carbon nanotubes in the composite carbon nanotube film are interwoven to form a network structure, so that the nanosphere is The mechanical properties of the carbon nanotube composite membrane 122 are increased, and the carbon nanotube composite membrane 122 has a plurality of uniform and regularly arranged micropores having a pore diameter of between 1 nm and 500 nm. It can be understood that when the sample to be tested carried by the Raman scattering substrate 100 is a solution, the network structure easily forms a solution film of the solution dripping on the surface of the carbon nanotube film to form a uniformly dispersed solution film, thereby facilitating detection. . At the same time, the "node" of the carbon nanotubes forming the network structure overlaps with each other, and the sensitivity of the carbon nanotube composite film 122 to the sample can be improved. In this embodiment, the carbon nanotube composite film 122 comprises two layers of carbon nanotube film laminated, and the intersection angle α between the carbon nanotubes in the adjacent carbon nanotube film is approximately equal to 90 degrees. Forming a network structure.

The metal particles may be formed on the surface of the carbon nanotube by electron beam evaporation or electron beam sputtering. Specifically, when the metal gas formed by electron beam evaporation or electron beam sputtering is in contact with the wall of the carbon nanotube, The metal gas is deposited on the surface of the tube wall of the carbon nanotube. Due to the surface tension of the metal, it will aggregate into metal particles on the surface of the carbon nanotube. Preferably, the metal particles are formed on the surface of each of the carbon nanotubes by electron beam evaporation, and a plurality of metal particles spaced apart from each other are formed on the surface of the same carbon nanotube. The formation of the metal particles and the size of the particle diameter can be controlled by controlling the evaporation amount of the metal material on the surface of the carbon nanotube. The evaporation amount should not be too large, so as to prevent excessive metal material from depositing on the surface of the carbon nanotube to form a Metal film instead of metal particles. It can be understood that in the actual evaporation process, it is necessary to control the evaporation amount of the metal material on the surface of the carbon nanotube by monitoring the thickness of the metal material. Specifically, the thickness of the metal material on the surface of the carbon nanotube film should be controlled between 1 nm and 100 nm, so that it exists in the form of metal particles. The material of the metal particles comprises a transition metal or a noble metal. Preferably, the material of the metal particles comprises one or more of gold, silver, copper and palladium; the metal particles are quasi-spherical and have a particle diameter of from 1 nm to 100 nm. Between meters, preferably, the particle size is between 18 nm and 22 nm; the gap between two adjacent metal particles is between 1 nm and 15 nm, preferably, two adjacent metals The gap between the particles is between 1 nm and 5 nm. It can be understood that since the particle diameter of the metal particles is small and the interval between adjacent metal particles is small, the particle diameter of the metal particles and the interval between adjacent metal particles are relatively uniform. Under the excitation of the external incident photoelectric magnetic field, the metal surface plasma resonates and absorbs, so that the local electromagnetic field between the particles is enhanced, thereby causing the Raman signal enhancement of the molecule to enhance the sensitivity of the Raman scattering substrate 120.

Referring to FIG. 5, a transmission electron micrograph of the carbon nanotube composite film 122 of the present embodiment, the plurality of carbon nanotubes in the carbon nanotube composite film 122 are formed into two layers. And set the carbon nanotube film. The outer surface of the plurality of carbon nanotubes is spaced apart by a silver particle having a polycrystalline structure, and the particle size of the silver particle is between 18 nm and 22 nm; the gap between two adjacent silver particles is 1 nm~ Between 5 nanometers.

When the Raman scattering substrate 120 receives the light beam emitted by the emitting module 110, the plurality of metal particles in the Raman scattering substrate 120 form a diffuse reflecting surface, and the light beam is diffusely reflected. When the sample to be tested is adsorbed on the surface of the metal particle, the light beam irradiated on the surface of the metal particle elastically collides or inelastically collides with the molecule or functional group in the sample to be tested. The photon energy of the inelastic collision changes, and has the structural information of the molecule to be tested, forming a scattered light with a frequency change. Specifically, the structural information is a vibration mode of each molecule or functional group, which is a unique feature of the molecule.

The receiving module 130 is configured to collect scattered light scattered from the Raman scattering substrate 120 to form a Raman spectral feature map. Specifically, the receiving module 130 can be a multi-channel photon detector such as an electronic coupling device, or a single-channel photon detector such as a photomultiplier tube. From the Raman spectral property map, the vibration mode of the molecule or functional group of the sample to be tested and its corresponding molecule or functional group can be read.

The sample to be tested includes a solid sample (such as a sample powder, solid particles adsorbed with the sample, etc.) and a liquid sample (such as a droplet of an internally dissolved sample component, a molten sample, etc.). In the present embodiment, the sample to be tested is selected from 2.5 × 10 ^-3 moles per liter of pyridine aqueous solution and a concentration of 10 ^-6 moles per liter of rhodamine ethanol solution. The sample to be tested is adsorbed on the surface of the metal particles in the Raman scattering substrate 120. Please refer to FIG. 6. FIG. 6 shows a sample of a carbon nanotube film formed by a carbon nanotube and a metal particle in the detection system 100 and a sample of a carbon nanotube film formed by a carbon nanotube in the detection system 100. Raman spectral characteristics obtained when ×10 ^-3 moles of pyridine aqueous solution per liter. As can be seen from the figure, the Raman scattering peak of the pyridine is stronger than that in the detection system 100, and the vibration mode of each chemical bond of the pyridine can be clearly distinguished. Please refer to FIG. 7. FIG. 7 is a sample of a carbon nanotube composite film formed by a carbon nanotube and a metal particle in the detection system 100 and a sample for testing a carbon nanotube film formed by the carbon nanotube in the detection system 100. A Raman spectral characteristic obtained when 10 to ⁶ moles per liter of rhodamine ethanol solution. As can be seen from the figure, although the molecule of rhodamine is a fluorescent molecule, usually the Raman signal of the fluorescent molecule is masked by the fluorescent background, but the Raman scattering peak in the detection system 100 is stronger than that which can be significantly enhanced. .

The Raman scattering substrate 120 includes a carbon nanotube composite film 122 comprising a plurality of carbon nanotubes having a smaller size, and the carbon nanotubes have a larger specific surface area, thus The metal particles can be densely arranged on the surface of the carbon nanotube composite film, so that the number of metal particles per unit area is large, even if the density of the metal particles per unit area is large. Thereby, the Raman scattering substrate 120 has better stability and sensitivity.

The carbon nanotube composite membrane 122 in the Raman scattering substrate 100 includes a plurality of carbon nanotubes having a smaller size and a larger specific surface area, and the gap between adjacent carbon nanotubes is relatively uniform and relatively small. Thereby, the plurality of metal particles disposed on the surface of the carbon nanotube film can be uniformly and densely arranged and not easily agglomerated. Therefore, the Raman detection system fabricated using the Raman scattering substrate 100 has a wide range of applications and high sensitivity, and can be used to characterize structural information of various molecules. Specifically, it can detect a solution sample having a concentration greater than 1 x 10 ^-9 moles per liter.

Referring to FIG. 8 , a second embodiment of the present invention provides a detection system 200 including a transmitting module 210 , a Raman scattering substrate 220 , and a receiving module 230 . The transmitting module 210 emits a light beam to the Raman scattering substrate 220; the light beam is scattered through the Raman scattering substrate 220 to form scattered light; and the receiving module 230 is configured to collect scattered light scattered from the Raman scattering substrate 220, A Raman spectral feature map is formed.

The Raman scattering substrate 220 includes a frame 221 and a carbon nanotube composite film 222. The frame 221 is fixed around the carbon nanotube composite membrane 222 for fixing the carbon nanotube composite membrane 222. The carbon nanotube composite membrane 222 includes at least one carbon nanotube film formed by a plurality of carbon nanotubes, metal particles formed on the surface of the carbon nanotube, and disposed between the metal particles and the surface of the carbon nanotube The buffer layer. The plurality of carbon nanotubes are evenly arranged, parallel to each other and combined by a van der Waals force, and the plurality of carbon nanotubes constitute at least one self-supporting carbon nanotube film.

The detection system 200 provided by the embodiment of the present invention has the same structure and principle as the detection system 100 provided by the first embodiment. The main difference is that the emission module 210 illuminates the light intensity of the Raman scattering substrate 220. In one embodiment, the emission module 110 illuminates a quarter of the intensity of the Raman scattering substrate 120. The Raman scattering substrate 220 further includes a buffer layer disposed between the metal particles and the surface of the carbon nanotubes. Preferably, the buffer layer covers the surface of each of the carbon nanotubes, and the surface of each of the carbon nanotubes is Has a buffer layer. The structure formed after the surface of the carbon nanotube is coated with the buffer layer is still a tubular shape, and only the diameter of the tube is increased. The material of the buffer layer is an oxide comprising cerium oxide or magnesium oxide. The buffer layer has a thickness of between 10 nm and 100 nm, preferably the buffer layer The thickness is between 15 nm and 30 nm. In this embodiment, the buffer layer is made of cerium oxide and has a thickness of 20 nm. The buffer layer is used to insulate the metal particles from the carbon nanotubes and prevent electron transfer between the metal particles and the carbon nanotubes. At the same time, by providing the buffer layer, the metal particles have a relatively uniform deposition surface, and the metal particles are relatively well-balanced in all directions, so that the uniformity of the radius of curvature of the metal particles can be made better, thereby making the metal particles more uniform. Close to the sphere. It can be understood that when the Raman scattering substrate 220 does not include a buffer layer, the metal particles are directly disposed on the carbon nanotubes, and the radius of the long axis along the growth direction of the carbon nanotubes is large.

Referring to FIG. 9, a transmission electron micrograph of the carbon nanotube composite film 222 of the present embodiment is formed. The plurality of carbon nanotubes in the carbon nanotube composite film 222 are formed with two stacked and cross-shaped carbon nanotube films. . The outer surface of the plurality of carbon nanotubes is spaced apart by a silver particle having a polycrystalline structure, and the particle size of the silver particle is between 18 nm and 22 nm; and an outer surface of the carbon nanotube is formed between the outer surface of the carbon nanotube and the silver particle. There is a buffer layer of 20 nm thick ceria; on the surface of the same carbon nanotube, the gap between two adjacent silver particles is between 1 nm and 5 nm. Comparing Fig. 5 in the first embodiment of the present invention, the silver particles in the embodiment of the present invention have a more uniform deposition surface, that is, the radius of curvature thereof is more uniform, that is, the shape of the silver particles is closer to a spherical shape.

Referring to FIG. 10, in the detection system 200, the carbon nanotube composite film 222 formed by the carbon nanotubes, the buffer layer and the metal particles in the detection system 200 and the carbon nanotube film formed by the carbon nanotubes are tested. A Raman spectral characteristic diagram obtained when 2.5 x 10 ^-3 moles of pyridine aqueous solution per liter. Please refer to FIG. 11 , which is a carbon nanotube composite film formed by a carbon nanotube, a buffer layer and a metal particle in a Raman scattering substrate in the detection system 200 of the present embodiment, and a carbon nanotube film formed from a carbon nanotube. A Raman spectral characteristic diagram of the sample to be tested is 10 ^-6 moles per liter of rhodamine ethanol solution.

The carbon nanotube composite film 222 in the detection system 200 of the embodiment of the present invention further includes a buffer layer disposed on the surface of the metal particle and the carbon nanotube tube. between. By disposing the buffer layer, the metal particles are disposed on the buffer layer instead of being directly disposed on the surface of the carbon nanotube, so that the metal particles have a relatively uniform deposition surface, so that the metal particles are stressed in various directions. The uniformity of the radius of curvature is better, and the metal particles are more likely to generate surface plasmon resonance excitation. Therefore, the Raman spectral characteristic map obtained by the detection system 200 is clearer and the enhancement effect is more obvious. Specifically, the buffer layer is made of an insulating material. Preferably, the buffer layer is made of an oxide such as cerium oxide, magnesium oxide or the like; and the buffer layer has a thickness of between 10 nm and 100 nm, preferably The thickness of the buffer layer is between 15 nm and 30 nm. In this embodiment, the buffer layer is made of cerium oxide and has a thickness of 20 nm. Referring to FIG. 12, a comparison chart of Raman spectral characteristics obtained when the 10-6 moles per liter of rhodamine ethanol solution is detected in the first embodiment detection system 100 and the second embodiment detection system 200, respectively. It can be seen from the comparison chart that since the metal particles are more likely to generate surface plasmon resonance excitation after the buffer layer is disposed, the Raman spectral characteristic map obtained by the detection system 200 is clearer and the enhancement effect is more obvious. Even if the intensity of the beam is only one quarter of the intensity of the beam in the detection system 100 of the first embodiment.

Please refer to FIG. 13 and FIG. 14. FIG. 13 is a diagram of a third embodiment of the present invention. The system 300 includes a transmitting module 310, a Raman scattering substrate 320, and a receiving module 330. The transmitting module 310 is configured to emit a light beam to the Raman scattering substrate 320; the light beam is scattered through the Raman scattering substrate 320 to form scattered light; and the receiving module 330 is configured to collect scattering scattered from the Raman scattering substrate 320. Light forms a Raman spectral feature map.

The Raman scattering substrate 320 includes a substrate 321 and a carbon nanotube composite film 322 formed on the surface of the substrate 321 . The substrate 321 is used to support the carbon nanotube composite film 322. The structure and material of the substrate 321 are not limited. Preferably, the substrate 321 has a good light transmittance. A portion of the photons in the beam are directly incident on the base low 321 . If the substrate 321 has a good light transmittance, the photons will be directly emitted; otherwise, the portion will be reflected by the substrate 321 and the photons emitted therefrom. It is also possible to illuminate the carbon nanotubes in the carbon nanotube composite membrane 322 to form scattered light that will interfere with the scattered light of the molecular structure of the sample to be tested. This is detrimental to the detection of the sample to be tested by the Raman detection system 300. The carbon nanotube composite membrane 322 includes a carbon nanotube membrane formed of a plurality of carbon nanotubes and a plurality of metal particles disposed on the surface of the carbon nanotube membrane. The plurality of carbon nanotubes are evenly arranged, substantially parallel to each other and joined by van der Waals forces.

The detection system 300 provided by the embodiment of the present invention has the same structure and principle as the detection system 100 provided by the first embodiment, and the main difference is that the plurality of carbon nanotubes in the carbon nanotube film are substantially perpendicular to the nanometer. The surface of the carbon nanotube film, i.e., the plurality of carbon nanotubes, is arranged in an array and substantially perpendicular to the surface of the carbon nanotube film to form an array of carbon nanotubes. The metal particles are basically The carbon nanotube array is disposed away from the end of the substrate 321 to form a scattering surface, that is, the metal particles are disposed substantially at one end of the carbon nanotube array opposite to the substrate 321 . Referring to FIG. 14, in the embodiment, the metal particles have a particle diameter of between 10 nm and 50 nm, and each of the carbon nanotubes is provided with a metal particle at the end.

The carbon nanotubes can be single-walled carbon nanotubes, double-twisted carbon nanotubes or multi-walled carbon nanotubes. Referring to FIG. 15, in the detection system 300, the carbon nanotube composite film 320 formed by the multi-walled carbon nanotubes and the metal particles and the carbon nanotube film formed by the multi-walled carbon nanotubes are detected in the detection system 300. The Raman spectral characteristics obtained when the sample was measured in 10-6 moles per liter of rhodamine ethanol solution. The metal particles are silver particles having a particle diameter of between 13 nm and 17 nm. Referring to FIG. 16, in the detection system 300, a carbon nanotube composite film 322 formed of a single-walled carbon nanotube, a 13 nm to 17 nm metal particle, and a Raman scattering substrate in FIG. Single-walled carbon nanotubes, nanocarbon tube composite membrane 322 formed by 28 nm to 32 nm metal particles, and nanocarbon tube membrane formed by single-walled carbon nanotubes, the sample to be tested is 10-6 moles per sample. Raman spectral characteristics obtained when the rhodamine ethanol solution is ascended.

As can be seen from Fig. 15 and Fig. 16, in the case where the particle diameter of the metal particles is equivalent, the carbon nanotube composite film 322 composed of a single-walled carbon nanotube is composed of a nanometer composed of a multi-walled carbon nanotube. The Raman spectral characteristic of the carbon nanotube composite film 322 is more obvious, and the enhancement effect of the Raman spectrum of the sample to be tested is more obvious. This is because the density of the carbon nanotube film composed of multi-walled carbon nanotubes is slightly larger than that of the carbon nanotube film composed of single-walled carbon nanotubes, resulting in an increase in carbon content per unit area, thereby making nano The light transmittance of the carbon tube composite film 322 is decreased, and the increase is not detected. The amount of photon scattering by the collision of sample molecules. When the photon in the beam does not collide with the sample molecule to be tested and is directly scattered through the carbon nanotube, the partially scattered light will have molecular structure information in the carbon nanotube, thereby having the molecular structure of the sample to be tested. The scattered light of the information causes interference. That is, the Raman spectrum intensity of the sample to be tested obtained by the carbon nanotube film formed by the carbon nanotubes is large, so that the Raman spectral intensity obtained by the carbon nanotube composite film 322 and the carbon nanotubes are obtained. The contrast of the Raman spectral intensity obtained by the film is reduced, thereby reducing the enhancement effect of the Raman spectrum of the sample to be tested.

The Raman scattering substrate comprises a carbon nanotube composite membrane comprising a plurality of carbon nanotubes having a smaller size and a larger specific surface area. Therefore, the metal can be densely arranged on the surface of the carbon nanotube composite film with a small particle diameter. Thereby, the Raman scattering substrate has better stability and sensitivity.

In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above description is only a preferred embodiment of the present invention, and it is not possible to limit the scope of the patent application of the present invention. Equivalent modifications or variations made by those skilled in the art in light of the spirit of the invention are intended to be included within the scope of the following claims.

100‧‧‧Detection system

110‧‧‧Transmission module

120‧‧‧ Raman scattering substrate

121‧‧‧Support structure

122‧‧‧Nano Carbon Tube Composite Film

130‧‧‧ receiving module

Claims (23)

A Raman scattering substrate is improved in that it comprises a carbon nanotube composite membrane comprising at least one carbon nanotube membrane and a plurality of metal particles, the carbon nanotube membrane comprising a plurality of nanometer membranes The carbon tube, the plurality of metal particles are disposed on the surface of the plurality of carbon nanotubes, and the plurality of carbon nanotubes in the carbon nanotube film are arranged in a preferred orientation in one direction. The Raman scattering substrate according to Item 1, wherein the plurality of carbon nanotubes are uniformly distributed, and the adjacent carbon nanotubes are combined by a van der Waals force. The Raman scattering substrate of claim 1, wherein the carbon nanotube film is a self-supporting structure. The Raman scattering substrate of claim 1, wherein the Raman scattering substrate further comprises a frame through which the carbon nanotube composite film is at least partially suspended. The Raman scattering substrate of claim 4, wherein the carbon nanotube composite film comprises a multilayered carbon nanotube film laminate arrangement. The Raman scattering substrate of claim 1, wherein the plurality of carbon nanotubes in the carbon nanotube film are substantially parallel to each other and substantially parallel to the surface of the carbon nanotube film, the plurality of carbon nanotubes Connected end to end by Van der Valli. The Raman scattering substrate of claim 1, wherein the Raman scattering substrate further comprises a substrate having a surface, the carbon nanotube composite film covering the surface. The Raman scattering substrate of claim 7, wherein the carbon nanotube film The plurality of carbon nanotubes are substantially perpendicular to the surface of the carbon nanotube film and are combined by Van der Waals force. The Raman scattering substrate of claim 1, wherein each of the carbon nanotube surfaces is provided with at least one metal particle. The Raman scattering substrate of claim 1, wherein the plurality of metal particles are spaced apart. The Raman scattering substrate according to Item 1, wherein the gap between two adjacent metal particles is between 1 nm and 15 nm. The Raman scattering substrate according to claim 11, wherein a gap between two adjacent metal particles is between 1 nm and 5 nm. The Raman scattering substrate according to Item 1, wherein the metal particles have a particle diameter of between 10 nm and 50 nm. The Raman scattering substrate according to Item 1, wherein the metal particles have a particle diameter of between 18 nm and 22 nm. The Raman scattering substrate according to Item 1, wherein the material of the metal particles is a transition metal or a noble metal. The Raman scattering substrate according to Item 1, wherein the metal particles are polycrystalline silver particles having a particle diameter of between 18 nm and 22 nm, between two adjacent silver particles. The gap is between 1 nm and 5 nm. The Raman scattering substrate of claim 1, wherein the carbon nanotube composite film further comprises a buffer layer disposed between the metal particles and the carbon nanotubes. The Raman scattering substrate of claim 17, wherein the material of the buffer layer is an oxide. The Raman scattering substrate of claim 17, wherein the buffer layer has a thickness between 10 nm and 100 nm. The Raman scattering substrate according to Item 17, wherein the buffer layer is made of cerium oxide and has a thickness of from 18 nm to 22 nm. A Raman scattering substrate, which is improved in that it comprises a carbon nanotube composite membrane comprising at least one carbon nanotube membrane, a plurality of buffer layers and a plurality of metal particles, the carbon nanotube membrane The plurality of carbon nanotubes are disposed on the surface of the plurality of carbon nanotubes, and the plurality of metal particles are disposed on the surface of the plurality of buffer layers, and the plurality of carbon nanotubes in the carbon nanotube film are preferentially oriented in one direction Orientation. A Raman scattering substrate, which is improved in that it comprises a carbon nanotube composite film comprising a film structure formed by laminating two layers of carbon nanotube film layers, a buffer layer setting On the surface of the film structure, a plurality of metal particles are spaced apart from the surface of the buffer layer facing away from the film structure, and the carbon nanotube film comprises a plurality of carbon nanotubes connected end to end by van der Waals force and is substantially optimized in the same direction Oriented, the plurality of carbon nanotubes in the carbon nanotube film are arranged in a preferred orientation in one direction. A Raman detection system includes a transmitting module, a Raman scattering substrate and a receiving module; the transmitting module is configured to emit a light beam to the Raman scattering substrate; the Raman scattering substrate is used to transmit the transmitting module The light beam is scattered; the receiving module is configured to collect scattered light scattered from the Raman scattering substrate to form a Raman spectral characteristic map; The improvement is that the Raman scattering substrate comprises a carbon nanotube composite membrane comprising at least one carbon nanotube membrane and a plurality of metal particles, the nanocarbon membrane comprising a plurality of uniformly distributed a carbon carbon tube, the adjacent carbon nanotubes are combined by a van der Waals force, and the plurality of metal particles are disposed on the surface of the plurality of carbon nanotubes, and the plurality of carbon nanotubes in the carbon nanotube film are preferentially oriented in one direction arrangement.