Mass Sensor and Measurement Method Based on Boron Nitride Carbon Nanotube Heterostructure

Abstract

This invention relates to the field of nanoscale mass sensors, and more particularly to a mass sensor based on a boron nitride-carbon nanotube heterostructure. It comprises boron nitride nanotubes and carbon nanotubes disposed within the boron nitride nanotubes; the boron nitride-carbon nanotubes form a heterostructure. The mass sensor provided by this invention is small in size, highly sensitive, and capable of detecting minute masses. The chemical inertness of the outer boron nitride nanotubes ensures the stability of the mass sensing performance of the sensor, while the excellent mass sensing performance of both the boron nitride and carbon nanotubes ensures the sensitivity of the mass sensor.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of nanoscale mass sensors, and in particular to a mass sensor based on boron nitride carbon nanotube heterostructure. BACKGROUND

[0002] At present, mass sensors have played an important role in industrial production, and through mass sensors, cells and biological macromolecules such as proteins, DNA, etc. can be detected. Compared with traditional mass sensor materials including silicon, metal and low-dimensional nanomaterials, current mass sensors are developing towards miniaturization, high sensitivity and high stability.

[0003] Among many mass sensor materials, carbon nanotubes have excellent mechanical properties and electrical conductivity and have excellent effects in mass sensing, and are widely used in biological detection and gas sensing fields. However, carbon nanotube mass sensors are easily disturbed by external environment, and temperature change will affect the accuracy of carbon nanotube mass sensors. SUMMARY

[0004] The technical problem to be solved by the present application is to solve the existing problems and provide a mass sensor based on boron nitride carbon nanotube heterostructure with high sensitivity and high stability and a measurement method thereof.

[0005] The present application provides the following technical scheme: a mass sensor based on boron nitride carbon nanotube heterostructure, comprising a boron nitride nanotube and a carbon nanotube arranged in the boron nitride nanotube; the boron nitride carbon nanotube is a heterostructure.

[0006] Further, the boron nitride nanotube is zigzag-shaped, and the carbon nanotube is armchair-shaped.

[0007] Further, the heterostructure is preferably a double-layer coaxial heterostructure; the length of the boron nitride nanotube is the same as that of the carbon nanotube, and the centers of mass coincide.

[0008] Further, the length of the boron nitride carbon nanotube is 10 nm, and the difference between the inner and outer radii of the boron nitride nanotube and the carbon nanotube is The upper and lower floating does not exceed

[0009] Further, the boron nitride nanotube and the carbon nanotube are defect-free nanotubes.

[0010] Further, the boron nitride carbon nanotube is (17, 0) BNNT, and the carbon nanotube is (5, 5) CNT.

[0011] This invention also discloses a measurement method for a mass sensor based on a boron nitride carbon nanotube heterostructure, comprising the aforementioned boron nitride carbon nanotube heterostructure mass sensor, and including the following steps:

[0012] S1. Treat the adsorbed particle to be tested as a point mass, whose mass is uniformly distributed on the inner and outer layers of atoms near the center of mass;

[0013] S2. Apply a certain displacement along the y-axis to the inner and outer layers of atoms near the center of mass of the mass sensor, and then release the displacement constraint to allow the mass sensor to oscillate freely for 500 ps;

[0014] S3. Perform a fast Fourier transform on the displacement of the centroid along the y-axis to obtain the frequency domain variation spectrum of the mass sensor. The marked frequencies are the resonant frequencies of the mass sensor under the current adsorption mass.

[0015] S4. Based on the different resonant frequencies of the mass sensor under different adsorption masses, the magnitude of the adsorption mass is obtained by the change in the resonant frequency of the mass sensor before and after the adsorption of the adsorbed particles to be tested.

[0016] Furthermore, the applied displacement length cannot exceed 2% of the mass sensor length.

[0017] Furthermore, the nanomass sensor is fixed at both ends.

[0018] The beneficial effects of this invention compared to the prior art are as follows:

[0019] The mass sensor provided by this invention is small in size, highly sensitive, and capable of detecting minute masses. The chemical inertness of the outer boron nitride nanotubes ensures the stability of the mass sensor's mass sensing performance, while the excellent mass sensing performance of both boron nitride and carbon nanotubes ensures the sensor's sensitivity. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of the mass sensor in this invention; the dots in the figure represent the mass detected by the sensor, the boxes represent the fixed ends of the mass sensor, and the arrows represent the direction of the applied initial displacement.

[0021] Figure 2 The length in the embodiment of the present invention is The vibration frequency domain diagram of the mass sensor when the adsorbed mass is 1000 μg is shown in the inset, which shows the displacement of its centroid along the y-axis.

[0022] Figure 3 This invention illustrates how the resonant frequency of the CNT(5,5)@BNNT(17,0) mass sensor with different lengths varies with the adsorbed mass in this embodiment.

[0023] Figure 4 This is a graph showing the relationship between the mass resolution and length of the mass sensor in an embodiment of the present invention;

[0024] Figure 5 This is a line graph showing the change in mass resolution of the mass sensor at different temperatures in an embodiment of the present invention.

[0025] Figure Labels

[0026] 1-Fixed end of mass sensor, 2-Adsorbed particle to be measured. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described more clearly and completely below with reference to the accompanying drawings in the embodiments of this invention.

[0028] This invention designs a boron nitride-carbon nanotube heterostructure mass sensor, comprising two structures: boron nitride nanotubes and carbon nanotubes, such as... Figure 1 As shown, boron nitride nanotubes are on the outside and carbon nanotubes are on the inside.

[0029] In the heterostructure, boron nitride nanotubes are preferably serrated, i.e. (n,0)BNNT, for example (17,0)BNNT; carbon nanotubes are preferably armchair shaped, i.e. (n,n)CNT, for example (5,5)CNT. Specific Implementation

[0031] This invention designs a boron nitride carbon nanotube heterostructure mass sensor, such as... Figure 1 As shown, it includes boron nitride nanotubes and carbon nanotubes, with the boron nitride nanotubes on the outside and the carbon nanotubes on the inside. Mass sensor fixing ends 1 are provided on both sides of the boron nitride carbon nanotubes; the adsorbed particles 2 to be measured are placed on atoms near the center of mass of the mass sensor.

[0032] The heterostructure consists of boron nitride nanotubes (17,0)BNNT and carbon nanotubes (5,5)CNT. This mass sensor can also be called a CNT(5,5)@BNNT(17,0) mass sensor.

[0033] The preferred heterostructure is a bilayer coaxial heterostructure, with both tubes having approximately the same length (10 nm) and coincident centroids; the difference between the inner and outer radii of the boron nitride nanotubes and the carbon nanotubes should be close. Fluctuation not exceeding Both boron nitride nanotubes and carbon nanotubes are defect-free nanotubes.

[0034] The boron nitride carbon nanotube heterostructure mass sensor provided by this invention operates as follows:

[0035] Treating the adsorbed particle 2 as a point mass, its mass is uniformly distributed across the adsorption sites, specifically the inner and outer layers of atoms near the center of mass.

[0036] A displacement of a certain length is applied along the y-axis to the inner and outer layers of atoms near the center of mass of the mass sensor. The applied displacement length cannot exceed 2% of the length of the mass sensor. Figure 1 As shown. Then the displacement constraint is released, allowing the mass sensor to oscillate freely for 500 ps to obtain the resonant frequency of the mass sensor.

[0037] like Figure 2 As shown, a fast Fourier transform of the displacement of the centroid along the y-axis can be used to obtain the frequency domain variation spectrum of the mass sensor, and the marked frequencies are the resonant frequencies of the mass sensor under the current adsorption mass.

[0038] The resonant frequency of the mass sensor varies with different adsorption masses. By observing the change in the resonant frequency of the mass sensor before and after particle adsorption, the magnitude of the adsorbed mass can be obtained, thus enabling the detection of minute masses.

[0039] Figure 3 The resonant frequencies of the mass sensor under different adsorption masses are shown.

[0040] Mass resolution refers to the minimum detectable mass of a mass sensor. In this embodiment, the mass resolution is the minimum detectable mass when the resonant frequency shifts by 2 GHz. The mass resolution is obtained by fitting the mass frequency shift curve and calculating it using formula (1):

[0041]

[0042] In the formula

[0043] f m —The resonant frequency after adsorption mass;

[0044] f—the resonance frequency when no adsorbed mass is present;

[0045] m—the mass of the adsorbate;

[0046] a – coefficient, which can be obtained through fitting. Figure 3 The data obtained are shown in Table 1.

[0047] Table 1. Values ​​of coefficient a for different lengths

[0048]

[0049] Figure 4 The mass resolution of the mass sensor is shown at different lengths.

[0050] In length of Its mass resolution can reach 38.7 μg, equivalent to the mass of 23 hydrogen atoms, indicating that the mass sensor can detect 10... 2 A tiny mass on the order of yg.

[0051] Figure 4 The mass resolution of the mass sensor was recorded when the temperature ranged from 100K to 400K.

[0052] When the temperature changes from 100K to 400K, the mass resolution of the mass sensor remains basically stable, with an average value of 283.5 μg and a fluctuation of no more than 12 μg.

[0053] This indicates that the mass sensing performance of the mass sensor maintains good stability within a certain temperature range.

[0054] The results above show that the designed mass sensor has good mass sensing performance and remains stable at different temperatures.

[0055] The above specific embodiments are only for illustrating the technical concept and structural features of the present invention, and are intended to enable those skilled in the art to implement them. However, the above content does not limit the scope of protection of the present invention. Any equivalent changes or modifications made in accordance with the spirit and essence of the present invention should fall within the scope of protection of the present invention.

Claims

1. A measurement method for a mass sensor based on a boron nitride carbon nanotube heterostructure, the mass sensor based on a boron nitride carbon nanotube heterostructure, characterized by The mass sensor based on the boron nitride carbon nanotube heterostructure comprises a boron nitride nanotube and a carbon nanotube arranged in the boron nitride nanotube; the boron nitride carbon nanotube is a heterostructure; The heterostructure is a double-layer coaxial heterostructure; the boron nitride nanotube and the carbon nanotube have the same length and the same center of mass; The length of the boron nitride carbon nanotube is 10 nm, and the difference between the inner and outer radii of the boron nitride nanotube and the carbon nanotube is 3.4 Å, and the up-and-down floating is not more than 0.1 Å; The boron nitride nanotube is a (17, 0) BNNT, and the carbon nanotube is a (5, 5) CNT; The boron nitride nanotube and the carbon nanotube are defect-free nanotubes; The fixing mode of the nanometer mass sensor is two-end fixing; comprising the following steps, S1. regarding the adsorbed particles to be measured as a mass point, the mass of which is uniformly distributed on the inner and outer two layers of atoms near the center of mass; S2. a displacement of a certain length is applied to the inner and outer two layers of atoms near the center of mass of the mass sensor along the y-axis, and then the displacement constraint is released, and the mass sensor is allowed to oscillate freely for 500 ps; S3. the displacement of the center of mass along the y-axis direction is subjected to fast Fourier transform, and the frequency domain variation spectrum of the mass sensor is obtained, and the marked frequency is the resonance frequency of the mass sensor under the current adsorbed mass; S4. according to the different resonance frequencies of the mass sensor under different adsorbed masses, the size of the adsorbed mass is obtained through the change of the resonance frequency of the mass sensor before and after adsorbing the adsorbed particles to be measured.

2. The measurement method of the mass sensor based on the boron nitride carbon nanotube heterostructure according to claim 1, characterized in that: The boron nitride nanotube is zigzag-shaped, and the carbon nanotube is armchair-shaped.

3. The measurement method of the mass sensor based on the boron nitride carbon nanotube heterostructure according to claim 1, characterized in that: The length of the applied displacement cannot exceed 2% of the length of the mass sensor.

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