TWI438509B - Fiber porbe and detecting system having same - Google Patents

Description

Fiber optic probe and sensing system with the same

The invention relates to a fiber optic probe and a sensing system having the same.

The sensing system consisting of surface-enhanced Raman scattering technology and fiber combination has potential application value in chemical, biological and environmental monitoring due to its flexible portability. Previous sensing systems included a fiber optic probe that was formed by physically or electrochemically plating silver particles at a probing end of a conventional fiber optic. The physical or electrochemical methods include electroplating, evaporation, sputtering, and the like. The fiber optic probe is excited by the incident photoelectric field, and the surface of the metal particle undergoes plasmon resonance absorption, so that the local electromagnetic field between the particles is enhanced, thereby causing the Raman signal of the molecule adsorbed on the probe to be enhanced.

The silver particles in the fiber optic probe are directly plated on the surface of the detecting end to form a unitary structure with the detecting end. When the silver particles need to be removed, the structure of the detecting end is generally destroyed, thereby destroying the structure of the optical fiber. . Therefore, when the silver particles are damaged to render the fiber optic probe inoperable, the fiber optic probe is difficult to reuse because the silver particles are difficult to remove.

In view of this, it is necessary to provide a fiber optic probe with high sensitivity and fiber reusability and a sensing system with the fiber optic probe.

A fiber optic probe includes an optical fiber and a carbon nanotube composite film. The carbon nanotube The composite film includes a carbon nanotube film structure and a plurality of metal particles. The carbon nanotube membrane structure is disposed on an outer surface of one end of the optical fiber, and the carbon nanotube membrane structure comprises a plurality of carbon nanotubes. The plurality of metal particles are disposed on the surface of the plurality of carbon nanotubes.

A fiber optic probe includes an optical fiber, a carbon nanotube film structure, and a metal layer. The fiber includes a probe end. The carbon nanotube membrane structure is disposed on an outer surface of the detecting end of the optical fiber, and the carbon nanotube membrane structure comprises a plurality of carbon nanotube tubes. The metal layer is disposed on a surface of the carbon nanotube film structure, and the metal layer is composed of a plurality of metal particles.

A sensing system includes a transmitting module, a fiber optic probe, and a receiving module. The transmitting module emits a light beam to the fiber optic probe. The fiber optic probe scatters a light beam emitted by the transmitting module at an end of the fiber optic probe to form scattered light, and transmits the scattered light to the receiving module. The receiving module collects scattered light scattered from the fiber optic probe to form a Raman spectral feature map. The fiber optic probe includes an optical fiber and a carbon nanotube composite film. The carbon nanotube composite membrane comprises a carbon nanotube membrane structure and a plurality of metal particles. The carbon nanotube membrane structure is disposed on an outer surface of one end of the optical fiber, and the carbon nanotube membrane structure comprises a plurality of carbon nanotubes. The plurality of metal particles are disposed on the surface of the plurality of carbon nanotubes.

Compared with the prior art, the metal particles in the above fiber optic probe are disposed on the carbon nanotube film structure to form a carbon nanotube composite film with the carbon nanotube film structure without directly plating on the end of the optical fiber. Therefore, when the metal particles are damaged or contaminated by adsorbing the sample to be tested, the metal particles can be removed by removing the carbon nanotube composite film without destroying the structure of the optical fiber, thereby The fiber can be reused.

100‧‧‧Sensing system

10‧‧‧Transmission module

20‧‧‧ receiving module

30‧‧‧Fiber Optic Probe

31‧‧‧ fiber optic

311‧‧‧Detector

312‧‧‧End to be tested

32‧‧‧Nano Carbon Tube Composite Film

321‧‧‧Nano carbon nanotube membrane structure

322‧‧‧metal layer

323‧‧‧buffer layer

200‧‧‧samples to be tested

Figure 1 is a scanning electron micrograph of a carbon nanotube flocculation membrane.

Figure 2 is a scanning electron micrograph of a carbon nanotube rolled film.

Figure 3 is a scanning electron micrograph of a carbon nanotube film.

4 is a schematic structural view of a sensing system.

FIG. 5 is a partially enlarged schematic structural view of the sensing system of FIG. 4. FIG.

Fig. 6 is a schematic view showing the structure of a carbon nanotube composite membrane.

Figure 7 is a scanning electron micrograph of a carbon nanotube substrate.

Figure 8 is a transmission electron micrograph of a silver-nanocarbon tube substrate.

Figure 9 is a high resolution transmission electron micrograph of the silver-nanocarbon nanotube substrate of Figure 8.

Fig. 10 is a schematic view showing the structure of another carbon nanotube composite membrane.

Figure 11 is a transmission electron micrograph of a silver-buffer layer-nanocarbon nanotube substrate.

Figure 12 is a high resolution transmission electron micrograph of the silver-buffer layer-carbon nanotube substrate of Figure 11.

13 is a view showing the arrangement of the carbon nanotube substrate of FIG. 7, the silver-nanocarbon tube substrate of FIG. 8, and the silver-buffer layer-carbon nanotube substrate of FIG. 11 in the sensing system of FIG. 4; A Raman spectral characteristic diagram obtained when 2.5 x 10 ^-3 moles of pyridine aqueous solution per liter.

14 is a diagram showing the arrangement of the carbon nanotube substrate of FIG. 7, the silver-nanocarbon tube substrate of FIG. 8, and the silver-buffer layer-carbon nanotube substrate of FIG. 11 in the sensing system of FIG. Raman spectral characteristics obtained when 10-6 moles of rhodamine ethanol solution per liter.

The invention provides a sensing system, which comprises a transmitting module and an optical fiber Probe and a receiving module.

The transmitting module emits a light beam to the fiber optic probe to illuminate a sample to be tested adsorbed on the fiber optic probe to form scattered light of the sample to be tested at the fiber optic probe. The beam is a strong source of small bandwidth and having a fixed frequency, such as an argon ion laser. Preferably, the wavelength of the beam is between 450.0 nm and 514.5 nm. The light beam may further preferably be green light having a wavelength of 514.5 nm, and the green light of 514.5 nm has a large scattered light intensity at the same power with respect to light of other wavelengths, so that more scattered light can be formed.

The receiving module is configured to collect scattered light scattered from the fiber optic probe to form a Raman spectral feature map of the sample to be tested. Specifically, the receiving module can be directly coupled to the fiber optic probe. The receiving module 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 may be a solid sample (such as a sample powder, solid particles adsorbed with a sample, etc.), a liquid sample (such as a droplet of an internally dissolved sample component, a molten sample, etc.) or a gaseous sample. When the sample to be tested is a gaseous sample, the detecting end of the fiber optic probe can be directly placed in an environment in which the gaseous sample is located, and the content of the vapor molecules in the sample to be tested is greater than one billion in the air. 0.1. When the sample to be tested is a solid sample or a liquid sample, the probe end of the fiber probe is generally in direct contact with the sample to be tested. When the sample to be tested is a solid sample or a liquid sample, the probe end of the fiber probe may also be close to the sample to be tested. At this time, the sample to be tested has a certain degree of volatility and has a periphery around it. The vapor and the vapor molecules of the sample to be tested are present in the air in an amount of more than 0.1 parts per billion.

The fiber optic probe includes an optical fiber and a carbon nanotube composite film disposed on an outer surface of one end of the optical fiber.

The fiber may be selected from a single mode fiber or a multimode fiber. The optical fiber includes a detecting end and a detecting end, and the detecting end and the detecting end are opposite ends of the optical fiber. The shape of the detecting end is not limited. Preferably, the detecting end is a cylinder. The detecting end is optically connected to the receiving module, and is configured to transmit data in the optical fiber to the receiving module. The carbon nanotube composite membrane is disposed on an outer surface of the detecting end of the optical fiber. Preferably, the carbon nanotube composite membrane completely covers the outer surface of the detecting end.

The carbon nanotube composite membrane comprises a carbon nanotube membrane structure and a metal layer disposed on the surface of the carbon nanotube membrane structure.

The carbon nanotube film structure includes a plurality of carbon nanotubes formed on a surface of the detecting end. The plurality of carbon nanotubes may be substantially perpendicular to the surface of the probe end to form an array of carbon nanotubes. The plurality of carbon nanotubes may also be at an angle to the surface of the probe end. The plurality of carbon nanotubes may also be substantially parallel to the surface of the probe end, i.e., the plurality of carbon nanotubes are substantially parallel to the surface of the carbon nanotube membrane structure. Preferably, the plurality of carbon nanotubes are connected by a Van der Waals attractive force to form a self-supporting structure. The so-called "self-supporting" means that the carbon nanotube film structure can maintain its own specific shape without being disposed on a surface of a substrate. Since a large number of carbon nanotubes in the self-supporting carbon nanotube membrane structure are attracted to each other by van der Waals force, the carbon nanotube membrane structure has a specific shape to form a self-supporting structure.

When the carbon nanotube membrane structure is a self-supporting structure, the carbon nanotube membrane structure may be a membrane-like structure formed by at least one carbon nanotube membrane, and when the carbon nanotube membrane structure comprises a plurality of nanometer membrane structures In the carbon tube film, the plurality of carbon nanotube films are stacked, adjacent to the nano carbon The tube membranes are combined by van der Waals force.

Referring to FIG. 1 , the carbon nanotube film may be a carbon nanotube flocculation membrane, and the carbon nanotube flocculation membrane is a self-supporting nanometer obtained by flocculation of a carbon nanotube raw material. Carbon tube membrane. The carbon nanotube flocculation membrane comprises carbon nanotubes which are intertwined and uniformly distributed. The carbon nanotubes have a length greater than 10 microns, preferably from 200 microns to 900 microns, such that the carbon nanotubes are intertwined with each other. The carbon nanotubes are attracted to each other by van der Waals forces to form a network structure. Since the large number of carbon nanotubes in the self-supporting carbon nanotube flocculation membrane are attracted to each other and entangled by van der Waals force, the carbon nanotube flocculation membrane has a specific shape to form a self-supporting structure. . The carbon nanotube flocculation membrane is isotropic. The carbon nanotubes in the carbon nanotube flocculation membrane are uniformly distributed and randomly arranged to form a plurality of gaps or micropores having a size ranging from 1 nm to 500 nm. The gap or micropores can increase the specific surface area of the carbon nanotube membrane and adsorb more sample to be tested.

The carbon nanotube film may be a carbon nanotube rolled film, which is a self-supporting carbon nanotube film obtained by rolling a carbon nanotube array. The carbon nanotube rolled film comprises uniformly distributed carbon nanotubes, and the carbon nanotubes extend in a preferred orientation in the same direction or in different directions. The carbon nanotubes in the carbon nanotube rolled film partially overlap each other and are attracted to each other by the van der Waals force, and the carbon nanotube film has good flexibility and can be bent and folded. In any shape without breaking. Moreover, since the carbon nanotubes in the carbon nanotube rolled film are attracted to each other by the van der Waals force, the carbon nanotube film is a self-supporting structure. The carbon nanotubes in the carbon nanotube rolled film form an angle β with the surface of the growth substrate forming the carbon nanotube array, wherein β is greater than or equal to 0 degrees and less than or equal to 15 degrees, and the angle β is applied The pressure on the carbon nanotube array is related to the pressure, the smaller the angle, the smaller the angle Preferably, the carbon nanotubes in the carbon nanotube rolled film are aligned parallel to the growth substrate. The carbon nanotube rolled film is obtained by rolling a carbon nanotube array, and the carbon nanotubes in the carbon nanotube rolled film have different arrangement forms according to different rolling methods. Specifically, the carbon nanotubes can be arranged in disorder; referring to FIG. 2, when rolling in different directions, the carbon nanotubes are preferentially oriented in different directions; when rolled in the same direction, the carbon nanotubes are along a The fixed direction is preferred to extend. The length of the carbon nanotubes in the carbon nanotube rolled film is greater than 50 microns.

The area of the carbon nanotube rolled film is substantially the same as the size of the carbon nanotube array. The thickness of the carbon nanotube film is related to the height of the carbon nanotube array and the pressure of the rolling, and may be between 0.5 nm and 100 μm. It can be understood that the larger the height of the carbon nanotube array and the smaller the applied pressure, the larger the thickness of the prepared carbon nanotube rolled film; on the contrary, the smaller the height of the carbon nanotube array, the more the applied pressure Large, the smaller the thickness of the prepared carbon nanotube rolled film. There is a gap between adjacent carbon nanotubes in the carbon nanotube film, thereby forming a gap between 1 nm and 500 nm in the carbon nanotube film. Or micropores. The gap or micropores can increase the specific surface area of the carbon nanotube membrane and adsorb more sample to be tested.

The carbon nanotube film may be a carbon nanotube film, and the carbon nanotube film is a self-supporting structure composed of a plurality of carbon nanotubes. Referring to FIG. 3, the plurality of carbon nanotubes extend in a preferred orientation along the length direction of the carbon nanotube film. The preferred orientation means that the overall extension direction of most of the carbon nanotubes in the carbon nanotube film is substantially in the same direction. Moreover, the overall extension direction of the majority of the carbon nanotubes is substantially parallel to the surface of the carbon nanotube film.

Further, most of the carbon nanotubes in the carbon nanotube film are connected end to end by van der Waals force. Specifically, the carbon nanotube film is substantially extended in the same direction Each of the carbon nanotubes in each of the carbon nanotubes is connected end to end with a van der Waals force in the extending direction. Of course, there are a few carbon nanotubes in the carbon nanotube film that deviate from the extending direction. These carbon nanotubes do not constitute an obvious extension of the overall orientation of most of the carbon nanotubes in the carbon nanotube film. influences. The self-supporting carbon nanotube film does not require a large-area carrier support, and as long as the support force is provided on both sides, it can be suspended in the whole to maintain its own film state, that is, the carbon nanotube film is placed (or When fixed on two supports arranged at a certain distance, the carbon nanotube film located between the two supports can be suspended to maintain its own film state. The self-supporting is mainly achieved by the presence of continuous carbon nanotubes extending through the end-to-end extension of the van der Waals force in the carbon nanotube film. Specifically, the plurality of carbon nanotubes extending substantially in the same direction in the carbon nanotube film are not absolutely linear and may be appropriately bent; or are not completely aligned in the extending direction, and may be appropriately deviated from the extending direction. . Therefore, it is not possible to exclude partial contact between the carbon nanotubes juxtaposed in the majority of the carbon nanotubes extending substantially in the same direction. Specifically, the carbon nanotube film comprises a plurality of continuous and aligned carbon nanotube segments. The plurality of carbon nanotube segments are connected end to end by van der Waals force. Each carbon nanotube segment consists of a plurality of carbon nanotubes that are parallel to each other. The carbon nanotube segments have any length, thickness, uniformity, and shape. The carbon nanotube film has good light transmittance, and the visible light transmittance can reach 75% or more.

When the carbon nanotube film structure comprises 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 carbon nanotube film having a layer number of less than or equal to 10 layers, so that the number of carbon nanotubes per unit area is small, and the Raman light intensity of the carbon nanotube itself is made strong. It is kept in a small range, thereby reducing the Raman peak intensity of the carbon nanotubes in the Raman spectrum. In this embodiment, the The layered structure comprises a carbon nanotube film having a layer number of less than or equal to 4 layers, so that the layer structure has a transmittance of more than 40%. 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. The mechanical properties of the carbon nanotube membrane structure are increased. It can be understood that when the sample to be tested is a solution, the network structure easily forms droplets of the solution attached to the surface of the carbon nanotube film to form a uniformly dispersed solution film, thereby facilitating detection. At the same time, the "nodes" which form the network structure of the carbon nanotubes overlap each other, and the adsorption of the sample is good, and more samples to be tested can be adsorbed. In this embodiment, the carbon nanotube film structure comprises two layers of carbon nanotube film laminated, and the intersection angle α between the carbon nanotubes in the adjacent carbon nanotube film is substantially equal to 90 degrees. That is, the extending direction of the carbon nanotubes in the adjacent carbon nanotube film is substantially perpendicular.

The metal layer is disposed on one surface or two opposite surfaces of the carbon nanotube film structure. The metal layer can be formed by forming a metal material on the surface of the carbon nanotube film structure by electron beam evaporation or electron beam sputtering. A quartz crystal oscillator can be used to monitor the thickness of the metal layer. The metal material includes a transition metal or a noble metal, and preferably, the material of the metal includes one or more of gold, silver, copper, and palladium. The thickness of the metal layer is between approximately 1 nm and 45 nm.

Microscopically, the metal layer is a plurality of metal particles disposed on an outer surface or a portion of an outer surface of a carbon nanotube in the carbon nanotube film structure. It can be understood that the carbon nanotubes exposed on the surface of the carbon nanotube membrane structure are provided with more metal particles on the outer surface thereof, and the metal particles are quasi-spherical. It should be noted that the maximum one-dimensional size of the metal particles is substantially along the nanocarbon due to the non-wetting of the surface of the metal and the carbon nanotubes. The tube wall of the tube extends. Therefore, the diameter of the metal particles and the thickness of the vapor-deposited metal layer are not numerically corresponding, but are slightly larger than the thickness of the metal layer. However, the thicker the thickness of the metal layer, the larger the particle size of the metal particles. For example, when the thickness of the metal layer is approximately between 1 nm and 50 nm, the particle size of the metal particles constituting the metal layer is between 5 nm and 50 nm. The interparticle spacing between the plurality of metal particles is generally between 1 nm and 15 nm. That is, the plurality of metal particles are spaced apart to form a plurality of gaps between the plurality of metal particles, the gaps having a distance of substantially between 1 nm and 15 nm. In this embodiment, the particle spacing is between approximately 2 nanometers and 5 nanometers, and the particle size of the metal particles is approximately between 18 nanometers and 22 nanometers. Of course, it is not excluded that a very small portion, such as one percent of the metal particles having a particle size greater than 50 nm or less than 5 nm, does not exclude a very small portion, such as one percent of the particle spacing greater than 15 nm.

The carbon nanotube composite film may further include a buffer layer disposed between the carbon nanotube film structure and the metal layer. The buffer layer may be formed before the metal layer is formed on the surface of the carbon nanotube film structure. The buffer layer has a thickness of between approximately 10 nanometers and 100 nanometers. Preferably, the buffer layer has a thickness between approximately 15 nanometers and 30 nanometers. Microscopically, the buffer layer covers part or all of the surface of the carbon nanotubes in the carbon nanotube membrane structure. At this time, the metal particles are disposed on the surface of the buffer layer away from the carbon nanotube film structure, rather than directly on the surface of the carbon nanotube. The buffer layer can block 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 evenly distributed in all directions, so that the uniformity of the radius of curvature of the metal particles is better, thereby making the metal particles closer. The spherical shape increases the electromagnetic field enhancement coefficient and the Raman enhancement coefficient of the fiber optic probe. It can be understood that when the carbon nanotube composite membrane does not include buffering In the case of the 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. The material of the buffer layer includes an inorganic oxide material such as cerium oxide or magnesium oxide.

The preparation method of the carbon nanotube composite membrane is not limited as long as a plurality of metal particles capable of enhancing the Raman signal can be formed on the surface of the carbon nanotube membrane structure. For example, the carbon nanotube composite film can be formed by first forming the carbon nanotube film structure on the outer surface of the detecting end, and then forming a plurality of metal particles on the surface of the carbon nanotube film structure. . When the carbon nanotube film structure is a non-self-supporting structure, the outer surface of the detecting end may be formed by coating, in-situ growth or the like. When the carbon nanotube film structure is a self-supporting structure, the carbon nanotube composite film may also be directly disposed on the outer surface of the detecting end of the fiber optic probe by winding or adhesion. When the carbon nanotube composite membrane is wound at least two turns at the detecting end, the detecting end is provided with a multilayered carbon nanotube composite membrane. When the carbon nanotube composite membrane is wound one turn at the detecting end, only one layer of the carbon nanotube composite membrane is disposed on the detecting end. The carbon nanotube composite film may be attached to the detecting end only by van der Waals force, or may be bonded to the detecting end by a bonding agent. Specifically, since the carbon nanotube composite membrane includes a plurality of carbon nanotubes having a large specific surface area and a very small size, the carbon nanotube composite membrane may have a large specific surface area, and at this time, the nanometer The carbon tube composite film can directly adhere to the outer surface of the detecting end by its own adhesion.

Compared with the conventional fiber optic probe, the fiber optic probe of the present invention is prepared by forming a carbon nanotube composite film on the outer surface of the detecting end, and the method is relatively simple, and the outer surface of the fiber optic probe need not be roughened. The outer surface of the detecting end is a smooth surface. In the fiber optic probe of the present invention, the metal particles are formed on the carbon nanotube film structure, and do not form an integral structure with the detecting end, and the nanometer The carbon tube membrane structure and the detection end are two structures that are relatively independent. Therefore, when it is necessary to remove the metal particles from the surface of the optical fiber, it is only necessary to erase the entire carbon nanotube composite film by using a tool such as an eraser or a lens paper without damaging the structure of the optical fiber. It can be understood that since the carbon nanotube composite membrane already has a plurality of densely arranged metal particles, the carbon nanotube composite membrane itself can be regarded as a flexible Raman scattering substrate. Therefore, when preparing the fiber optic probe, it is equivalent to providing a flexible Raman scattering substrate at the detecting end. Preferably, the light transmittance of the Raman scattering substrate, that is, the light transmittance of the carbon nanotube composite film is greater than 40%.

When the sensing system is in operation, the detecting end of the fiber optic probe protrudes into a sample to be tested or is placed in an environment of a vapor molecule having a sample to be tested, and the carbon nanotube composite film is used to adsorb a large amount of Test sample molecules. When the transmitting module emits a light beam to the carbon nanotube composite film, photons in the light beam collide with the sample molecules to be tested adsorbed in the carbon nanotube composite film. 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 light beam collides with the sample molecule to be tested, scattered light having information about the molecular structure of the sample to be tested is formed. Part of the scattered light is transmitted to the detecting end via the total reflection of the optical fiber and transmitted to the receiving module via the detecting end. The receiving module can obtain a Raman spectrum of the sample to be tested by processing the received scattered light.

From the working process of the sensing system, the light beam emitted by the transmitting module can be directly irradiated to the carbon nanotube composite film, and the light beam can also be input to the optical fiber through the detecting end and irradiated through the optical fiber. To the carbon nanotube composite membrane. When the light beam is irradiated to the carbon nanotube composite film via the optical fiber, the sensing system may further Further comprising a light processing module, the light beam emitted by the transmitting module is processed by the light processing module and then transmitted to the carbon nanotube composite film via the optical fiber. The scattered light is transmitted by the optical fiber to the optical processing module, and then processed by the optical processing module and transmitted to the receiving module. That is, the light processing module is mainly used to provide and coordinate the optical paths of the light beam and the scattered light.

Since the metal particles in the fiber optic probe are disposed only on the carbon nanotube film structure instead of being directly disposed at the detecting end of the optical fiber, the outer surface of the detecting end of the optical fiber may be a smooth surface, without Roughening is performed. When it is necessary to remove the metal particles, it is only necessary to remove the carbon nanotube composite film wound or disposed at the detecting end without damaging the structure of the optical fiber, so that the optical fiber can be reused. Further, the carbon nanotube membrane structure is basically composed of a plurality of carbon nanotubes having a small size and a large specific surface area, and has a large specific surface area, thereby being capable of adsorbing more molecules of the sample to be tested. Moreover, since the carbon nanotube film structure has a large specific surface area, the metal particles can be densely arranged on the carbon nanotube film structure and form a plurality of small-sized particle pitches. 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 plasmon resonance absorption occurs on the metal surface, so that the local electromagnetic field between the particles is enhanced, thereby causing the Raman signal of the molecule to be tested to be enhanced to enhance the sensitivity of the fiber probe.

The sensing system of the present invention will be described in detail below with reference to the accompanying drawings in detail.

Referring to FIG. 4 , the sensing system 100 includes a transmitting module 10 , a receiving module 20 , and a fiber optic probe 30 . The transmitting module 10 and the receiving module 20 are respectively disposed at two ends of the fiber optic probe 30. One end of the fiber optic probe 30 extends into a sample to be tested 200.

The transmitting module 10 emits a light beam to the fiber optic probe 30 to illuminate the sample to be tested 200 adsorbed on the fiber optic probe 30, and the fiber optic probe 30 forms the scattered light of the sample to be tested 200. The scattered light is transmitted to the receiving module 20 via the fiber optic probe 30, and the receiving module 20 analyzes the scattered light to obtain a Raman spectral characteristic map of the sample to be tested 200. From the Raman spectral characteristic map, the vibration mode of the 200 molecules or functional groups of the sample to be tested and its corresponding molecules or functional groups can be read.

Referring to FIG. 5 together, the fiber optic probe 30 includes an optical fiber 31 and a carbon nanotube composite film 32 (Raman scattering substrate). The optical fiber 31 includes a detecting end 311 and a detecting end 312 disposed opposite to each other. The shape of the detecting end 311 is not limited. In the embodiment, the detecting end 311 is a cone whose diameter gradually decreases in a direction away from the fiber optic probe 30.

The carbon nanotube composite film 32 is wound around the outer surface of the detecting end 311. The carbon nanotube composite film 32 and the detecting end 311 may be bonded only by van der Waals force, or may be bonded with a bonding agent or the like. Referring to FIG. 6 further, the carbon nanotube composite membrane 32 includes a carbon nanotube membrane structure 321 and a metal layer 322. The metal layer 322 is disposed on a surface of the carbon nanotube film structure 321, and the metal layer 322 is disposed on a surface of the carbon nanotube film structure 321 away from the detecting end 311. Of course, the metal layer 322 may also be disposed on the surface of the carbon nanotube film structure 321 near the detecting end 311 or at the same time on both surfaces of the carbon nanotube film structure 321 . Referring to FIG. 7, in the embodiment, the carbon nanotube film structure 321 includes at least two layers of carbon nanotube film, and the extending direction of the carbon nanotubes in the adjacent carbon nanotube film is extended. Roughly vertical. The carbon nanotube membrane structure 321 is defined as a carbon nanotube substrate. Referring to FIG. 8 and FIG. 9 , the material of the metal layer 322 is selected from silver and has a thickness of approximately 5 nm. The particle diameter of the metal particles constituting the metal layer 322 is approximately 20 nm or so. The carbon nanotube composite membrane 32 is defined as a silver-nanocarbon nanotube substrate. Referring to FIG. 10, FIG. 11 and FIG. 12, the carbon nanotube composite film 32 may further include a buffer layer 323. The buffer layer 323 is made of cerium oxide and has a thickness of about 20 nm. The carbon nanotube composite membrane 32 is defined as a silver-buffer layer-nanocarbon nanotube substrate.

Referring to FIG. 13 and FIG. 14, the carbon nanotube substrate, the silver-carbon nanotube substrate, and the silver-buffer layer-carbon nanotube substrate are respectively disposed on the outer surfaces of the detecting ends 311 of the three optical fibers 31. The Raman spectrum characteristic diagram of the aqueous solution of the pyridine can be detected by extending the detection end 311 into a 2.5 × 10 ^-3 mole per liter aqueous solution of pyridine and a solution of 10 - ⁶ moles per liter of rhodamine ethanol. Raman spectral characteristics of Danming ethanol solution.

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‧‧‧Sensing system

10‧‧‧Transmission module

20‧‧‧ receiving module

30‧‧‧Fiber Optic Probe

31‧‧‧ fiber optic

312‧‧‧End to be tested

200‧‧‧samples to be tested

Claims (20)

A fiber optic probe comprising an optical fiber, wherein the optical fiber probe further comprises a carbon nanotube composite film disposed on an outer surface of one end of the optical fiber, the carbon nanotube composite film comprising: a carbon nanotube film structure The carbon nanotube film structure includes a plurality of carbon nanotubes; and a plurality of metal particles disposed on a surface of the plurality of carbon nanotubes. The fiber optic probe of claim 1, wherein the optical fiber has a detecting end, and the carbon nanotube composite film is disposed on an outer surface of the detecting end. The fiber optic probe of claim 2, wherein the outer surface of the detecting end is a smooth surface. The fiber optic probe of claim 2, wherein the carbon nanotube composite membrane covers the probe end. The fiber optic probe of claim 4, wherein the carbon nanotube composite film is bonded to the outer surface of the detecting end by a bonding agent. The fiber optic probe of claim 2, wherein the plurality of carbon nanotubes are substantially perpendicular to an outer surface of the probe end. The fiber optic probe of claim 2, wherein the plurality of carbon nanotubes are substantially parallel to the surface of the carbon nanotube film, and adjacent carbon nanotubes are bonded by van der Waals force. The fiber optic probe of claim 7, wherein the carbon nanotube film composite film is a self-supporting structure, and the carbon nanotube film composite film is directly wound around an outer surface of the detecting end. The fiber optic probe of claim 1, wherein the carbon nanotube membrane structure is a self-supporting structure, and the plurality of metal particles are adsorbed by the van der Waals force in the nanotube membrane structure. Carbon tube surface. The fiber optic probe of claim 1, wherein the carbon nanotube membrane structure comprises at least one layer of carbon nanotube membrane, wherein the carbon nanotubes in the carbon nanotube membrane extend in a preferred orientation in the same direction. Each of the carbon nanotubes in the majority of the carbon nanotube membranes extending in the same direction and the carbon nanotubes adjacent in the extending direction are connected end to end by van der Waals force. The fiber optic probe of claim 10, wherein the carbon nanotube membrane structure comprises at least two layers of carbon nanotube membrane laminates. The fiber optic probe of claim 10, wherein the number of layers of the carbon nanotube film in the carbon nanotube film structure is less than or equal to four layers. The fiber optic probe of claim 11, wherein the carbon nanotubes in the adjacent carbon nanotube film extend substantially perpendicularly. The fiber optic probe of claim 11, wherein a particle spacing between the plurality of metal particles disposed on a surface of the carbon nanotube is between 1 nm and 15 nm. The fiber optic probe of claim 1, wherein the metal particles have a particle size of between 5 nm and 50 nm. A fiber optic probe comprising an optical fiber, the optical fiber comprising a detecting end, wherein the optical fiber probe further comprises: a carbon nanotube film structure, the carbon nanotube film structure being disposed outside the detecting end of the optical fiber The surface, the carbon nanotube film structure comprises a plurality of carbon nanotubes; a metal layer disposed on a surface of the carbon nanotube film structure, the metal layer being composed of a plurality of metal particles. The fiber optic probe of claim 16, wherein the fiber optic probe further comprises a buffer layer disposed between the carbon nanotube film structure and the metal layer. The fiber optic probe of claim 16, wherein the carbon nanotube film structure and the metal layer form a carbon nanotube composite film, and the carbon nanotube composite film is a flexible Raman scattering substrate. The light transmittance of the carbon nanotube composite film is 40% or more. The fiber optic probe of claim 16, wherein the metal layer has a thickness between 1 nm and 50 nm. A sensing system includes a transmitting module, a fiber optic probe and a receiving module; the transmitting module transmits a light beam to the fiber optic probe; the fiber optic probe transmits a light beam emitted by the transmitting module to the fiber optic probe The end portion scatters to form scattered light and transmits the scattered light to the receiving module; and the receiving module collects scattered light scattered from the fiber optic probe to form a Raman spectral feature map; The fiber optic probe comprises a fiber and a carbon nanotube composite film, the carbon nanotube composite film comprises a carbon nanotube film structure and a plurality of metal particles, and the carbon nanotube film structure is disposed on a surface of one end of the fiber The carbon nanotube film structure includes a plurality of carbon nanotubes disposed on a surface of the plurality of carbon nanotubes.