WO2018192509A1 - Raman spectrometer sample platform and method for testing a light spectrum in situ thereby - Google Patents

Abstract

Disclosed are a Raman spectrometer sample platform and a method for testing a light spectrum in situ thereby, used for providing the Raman spectrometer with a horizontal magnetic field environment. The sample platform comprises: a base (10); magnetic brackets (4) fixed on the base (10); a first magnet (5) and a second magnet (7) which are installed on the magnetic brackets (4) and are correspondingly arranged for generating a horizontal magnetic field; a placement block (6) which is arranged between the first magnet (5) and the second magnet (7) and is used for placing a sample; and the placement block (6) is arranged in the middle part of the sample platform, and the magnetic brackets (4) are respectively located at two sides of the placement block (6). The sample platform can be directly placed on an object stage of the Raman spectrometer to provide experimenters with experimental conditions that can acquire Raman light spectrum data of the sample under different magnetic field intensities.

Description

Raman spectrometer sample stage and method for in situ test spectrum thereof Technical field

The invention relates to the field of spectrometers, in particular to a Raman spectrometer sample stage and a method for testing the spectrum in situ.

Background technique

At present, there are few types of external environmental sample stations applied to Raman spectrometers. The existing temperature sample stage in the laboratory allows the sample to be observed in a non-room temperature environment, achieving the effect of changing the temperature environment in which the sample is placed. When the sample needs to be observed in a magnetic field environment, the magnetic field environment has not been pulled down in the world. The exploration of Mann's spectrum, there is no magnetic field environment device applicable to Raman spectroscopy, lack of corresponding equipment, so that the laboratory can not obtain Raman spectral data of the test object under different magnetic field strength, so it can not meet the requirements of the experimental environment.

Therefore, the prior art needs further improvement.

Summary of the invention

In view of the above deficiencies in the prior art, the object of the present invention is to provide a Raman spectrometer sample stage and a method for inspecting the spectrum thereof in situ, which overcomes the problem that the prior art cannot provide the test object under different magnetic field strengths. Defects in Raman spectral data.

The technical solution adopted by the present invention to solve the technical problem is as follows:

A Raman spectrometer sample stage for providing a horizontal magnetic field environment for a Raman spectrometer, the sample stage comprising:

a base for supporting the entire sample stage;

a magnet holder fixed on the base for supporting the first magnet and the second magnet;

Correspondingly arranged to generate a horizontal magnetic field, and the first magnet and the second magnet mounted on the magnet holder;

a placement block disposed between the first magnet and the second magnet for placing a sample;

The placement block is disposed at an intermediate position of the sample stage, and the magnet holders are respectively located at two sides of the placement block.

The Raman spectrometer sample stage, wherein the magnet holder comprises: a first bracket and a second bracket respectively disposed above the two ends of the base, and a third bracket and a fourth bracket disposed adjacent to the placing block;

A groove-shaped sample placement area is formed between the third bracket, the fourth bracket and the placement block.

In the Raman spectrometer sample stage, the first magnet is an electromagnet or a permanent magnet, and the second magnet is an electromagnet or a permanent magnet.

The Raman spectrometer sample stage, wherein the first bracket, the second bracket, the third bracket and the fourth bracket are all provided with mounting holes: the mounting holes are used for fixing the two ends of the electromagnet, or Place the permanent magnet.

The Raman spectrometer sample stage, wherein the sample stage is further provided with a top cover;

The top cover is placed above the magnet and the sample, and the top cover is provided with a test port for performing Raman spectroscopy test corresponding to the placement block.

The Raman spectrometer sample stage, wherein the magnet holder of the sample stage is further provided with a front side plate, a rear side plate, a left side plate and a right side for shielding the magnetic field emitted by the first magnet and the second magnet Side panel.

The Raman spectrometer sample stage, wherein the front side panel or/and the rear side panel is disposed at a position corresponding to the sample placement area above the placement block, and a magnetic field strength test port is disposed.

The Raman spectrometer sample stage, wherein the front side panel, the rear side panel, the left side panel, the right side panel, the top cover and the base constitute the sample stage housing, and the sample stage housing has a rectangular parallelepiped shape and a cylinder Body shape or ellipsoid shape.

In the Raman spectrometer sample stage, the first magnet or the second magnet is a cylindrical magnet, a shoe magnet or a rectangular parallelepiped magnet.

The Raman spectrometer sample stage is used for a method for in situ testing of a spectrum, wherein the method comprises the steps of:

Step A: placing the sample stage on the stage of the Raman spectrometer;

Step B, measuring the magnetic field strength of the sample area, and adjusting the magnetic field strength to a predetermined value;

Step C: Obtain Raman spectral data of the sample under the current magnetic field strength.

[Advantageous Effects] The present invention provides a Raman spectrometer sample stage and a method for testing the spectrum in situ for providing a horizontal magnetic field environment for a Raman spectrometer, the sample stage comprising: a base; a magnet fixed on the base a bracket; mounted on the magnet holder, and correspondingly configured to generate a horizontal magnetic field of a first magnet and a second magnet; disposed between the first magnet and the second magnet for placing a sample placement block; The placement block is disposed at an intermediate position of the sample stage, and the magnet holders are respectively located at two sides of the placement block. The sample stage can be directly placed on the stage of the Raman spectrometer to provide Raman spectral data of the sample at different magnetic field strengths, which provides conditions for the experiment and improves the experimental operation efficiency.

DRAWINGS

1 is a schematic view showing the structure of a Raman spectrometer sample stage provided by the present invention.

2 is a schematic view showing the structure of the sample stage provided by the present invention after the upper casing is added.

Figure 3 is a schematic illustration of the sample on the sample stage of the present invention placed on a stage of a Raman spectrometer for testing.

4 is a flow chart showing the steps of a method for applying a sample stage of the present invention to an in situ test spectrum.

Figure 5a is a Raman spectrum of the sample taken without being placed in a magnetic field.

Figure 5b is a Raman spectrum obtained using a sample stage provided by the present invention to place a sample in a magnetic field environment in which no current is applied.

Figure 5c is a Raman spectrum obtained using a sample stage provided by the present invention to place a sample in a magnetic field environment with a current of 0.2 A.

Figure 5d is a Raman spectrum obtained using a sample stage provided by the present invention to place a sample in a magnetic field environment with a current of 0.4 A.

Figure 5e is a Raman spectrum obtained using a sample stage provided by the present invention to place a sample in a magnetic field environment with a current of 0.6 A.

Figure 5f is a Raman spectrum obtained using a sample stage provided by the present invention to place a sample in a magnetic field environment with a current of 0.6 A.

Fig. 5g is a graph comparing the intensity of the D peak in Figs. 5a to 5f as 1, and comparing the other peak intensities to obtain a comparison of the relative intensity values of the respective Raman vibration peaks.

detailed description

The present invention will be further described in detail below with reference to the accompanying drawings. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The traditional understanding of carbon materials is that carbon is not magnetic, so the external magnetic field does not cause changes in the structure of the carbon material. Because of this, in the study of characterizing the bonding structure of carbon materials by Raman spectroscopy, the influence of the magnetic field on its structure has never been considered, so all Raman spectrometers do not have the function of in-situ measurement of the magnetic field environment.

In recent years, as people's understanding of the magnetic behavior of carbon materials has deepened, it has been found that the spin-electron arrangement of carbon atoms changes with the external magnetic field, causing small changes in the C=C double bond structure, and this change may be The movement of the Raman scattering peak position, or the change of the intensity of the scattering peak, is captured. However, since there is no relevant test platform, there is no report on the in situ study of carbon material Raman spectroscopy in the magnetic field environment.

In order to help the laboratory to perform Raman spectroscopy of samples in a magnetic field environment, the present invention provides a horizontal magnetic environment sample stage for a Raman spectrometer in order to observe the Raman spectrum of the sample under an external magnetic field. Purpose, as shown in Figure 1, the sample stage comprises:

a base 10 for supporting the entire sample stage;

a magnet holder 4 fixed to the base 10 for supporting the first magnet 5 and the second magnet 7;

Correspondingly arranged to generate a horizontal magnetic field, and mounted on the magnet holder of the first magnet 5 and the second magnet 7;

a placing block 6 for placing a sample between the first magnet 5 and the second magnet 7;

The placement block 6 is disposed at an intermediate position of the sample stage, and the magnet holders 4 are respectively located at two sides of the placement block 6.

The sample stage adopts a method in which a first magnet and a second magnet interact to generate a horizontal magnetic field, and the magnetic poles of the two magnets are oppositely fixed horizontally on both sides of the sample placement area to generate a horizontal magnetic field to the sample (as shown in FIG. 1). Show). Preferably, in order to control the size of the sample stage and to prevent the sample stage from obstructing normal observation, a permanent magnet plus electromagnet is adopted. The permanent magnet material is neodymium iron boron, and its surface magnetic field strength is large and the volume is small, which can reduce the volume of the sample stage and enhance the magnetic field strength of the sample placement area; the electromagnet core material is permalloy, which has a large saturation magnetic induction intensity. With high magnetic permeability, this characteristic can be used to obtain a continuously adjustable and variable magnetic field at a relatively small current (0-0.8A) without overheating the electromagnet coil.

In order to facilitate the adjustment of the magnetic field strength, it is conceivable that there are two methods:

(1) Adjusting the distance between the magnetic poles of the two magnets can be achieved by providing a sliding connection between the magnet holder and the base.

(2) Adjust the current of the electromagnet, and the magnetic field strength of the sample placement area will change linearly with the current. The electromagnet can be powered by a continuously adjustable DC power supply to achieve a constant magnetic field direction and a linearly increasing or decreasing magnetic field strength.

Specifically, the magnet bracket 4 includes: a first bracket and a second bracket respectively disposed above the two ends of the base, and a third bracket and a fourth bracket disposed adjacent to the placing block; the third bracket and the fourth bracket A groove-shaped sample placement area is formed between the stent and the placement block.

The first magnet is an electromagnet or a permanent magnet, and the second magnet is an electromagnet or a permanent magnet.

The first bracket, the second bracket, the third bracket and the fourth bracket are respectively provided with mounting holes, as shown in FIG. 1 or FIG. 2, the mounting holes are used for fixing two ends of the electromagnet, or for placing Permanent magnet.

The sample stage is further provided with a top cover 3;

The top cover 3 is placed above the magnet and the sample, and the top cover 3 is disposed at a position corresponding to the placement block 6 with a test port for performing Raman spectroscopy.

The front side plate, the rear side plate, the left side plate and the right side plate for shielding the magnetic field emitted by the first magnet and the second magnet are further disposed around the magnet holder 4 of the sample stage, so as to be combined with the top cover and the base The outer casing that makes up the sample stage. Preferably, the outer shell of the sample stage is made of Q235 sheet material, and the Q235 belongs to low carbon steel and has a certain magnetic permeability. An enclosure made of this material encloses two magnets, but does not touch them, reducing the effect of the magnetic field on the Raman spectrometer. The front side panel, the rear side panel, the left side panel, the right side panel, the top cover, and the base form a shape of the sample stage housing, and a rectangular shape, a cylindrical shape, or an ellipsoid shape may be designed.

In order to facilitate testing the environmental magnetic field strength in which the sample is located, the front side plate or/and the rear side plate are disposed at positions corresponding to the sample placement area above the placement block, and a magnetic field strength test port is provided, and the magnetic field strength at the test sample is set. The Gaussian meter pen can be placed into the sample area through the test port.

Specifically, the first magnet or the second magnet is a cylindrical magnet, a shoe magnet or a rectangular parallelepiped magnet. As shown in Fig. 1, the electromagnet used in the present invention is all cylindrical. If a horizontal magnetic field is to be generated, the shape of the magnet is not limited, and it may be a rectangular parallelepiped or even a shoe-shaped magnet, as long as it is in the sample placement area. A horizontal magnetic field can be generated.

It is conceivable that in the present invention, only a pair of magnets are used. In order to obtain a large magnetic field strength adjustment range, the number of the first magnets and the second magnets may be greater than one, considering the type of the sample to be tested. The size can be widened correspondingly to the sample placement area, and the plurality of first magnets and the second magnet are arranged in parallel.

The selection of the magnet can be diversified. The invention adopts the design of the electromagnet plus the permanent magnet. In actual use, the design of the double-sided electromagnet or the double-sided permanent magnet can be adopted according to the requirements.

In order to simply place the sample stage of the present invention on the stage of the spectrometer, the magnetic shield case of the sample stage is designed to have a rectangular shape, and considering the magnetic shielding effect, the outer case of the sample stage should be designed to be cylindrical or elliptical. The shape of the ball to reduce the vertical penetration of the magnetic lines on all sides of the sample stage.

The invention discloses a method for applying the Raman spectrometer sample stage according to the invention to the in situ test spectrum according to the above-mentioned sample stage, as shown in FIG. 4, the steps thereof include:

Step S1: placing the sample stage on the stage of the Raman spectrometer;

Step S2, measuring a magnetic field strength of the sample area, and adjusting the magnetic field strength to a predetermined value;

Step S3: Obtain Raman spectrum data of the sample under the current magnetic field strength.

The above steps will be described in detail below using the specific use method of the sample stage. Referring to FIG. 2 and FIG. 3, the Raman spectroscopy test using the sample stage disclosed in the present invention is divided into the following steps:

Open the top of the sample stage, place the sample on the placement block, cover the top cover and place the sample stage on the stage of the Raman spectrometer. In order to achieve quick pick-and-place of the sample, and to ensure that the lens of the Raman spectrometer does not touch the sample stage, the top cover and the four side plates of the sample stage are not fastened, so the top cover can be regarded as natural. Placed on the sample stage.

Turn on the sample stage power supply, insert the Gauss meter pen from the groove of the front side plate into the sample placement area, observe the Gauss meter reading, adjust the current to the magnetic field strength to the desired value, and take back the Gauss meter to prepare for Raman spectroscopy. This step is to adjust the intensity of the magnetic field applied to the sample. If the current is adjusted, the Gauss meter reading can be used after adjusting the current. Through design testing, the present invention can generate a magnetic field of 570GS-880GS, corresponding to a current of 0-0.8A. A groove is formed in the center of the front side plate and the rear side plate of the sample stage to facilitate the measurement of the magnetic field strength of the sample surface after the power is turned on and the top cover is covered.

Switch the Raman spectrometer to a low magnification objective (10x), turn on the incandescent light source, slowly lower the objective lens to about 2 mm from the top of the sample stage, fine-tune the focal length until the image of the sample appears, turn off the incandescent lamp, and switch to the telephoto lens ( 50x) and turn on the laser source for precise focus. After the focus is completed, Raman spectroscopy can be performed. The focus work here is determined by the height and thickness of the sample in the sample stage, as well as the focal length of the lens. In the present invention, the upper surface of the placing block 6 is 9 mm from the upper surface of the top cover (as shown in Fig. 3), the thickness of the carbon film used for testing is less than 1 mm, and the focal lengths of the low magnification objective lens (10x) and the telephoto objective lens (50x) are both 10.6 mm, therefore, when focusing, you can first reduce the objective lens to 2 mm from the top of the sample table that can be discerned by the naked eye, and then fine-tune it.

After the test is completed, stop the operation software of the Raman spectrometer and lift the objective lens before moving out of the sample stage to cut off the power supply of the sample stage. Remove the sample stage from the stage, open the top cover, take out the sample, and complete the test.

Next, an effect obtained by performing the Raman spectroscopy using the sample stage provided by the present invention will be described.

Example 1:

Test sample: nanocarbon film 1 (graphene nanocrystalline structure), sample thickness: 200 nm; excitation light wavelength: 514 nm excitation light power: 1 mW. The measured results are shown in Figures 5a - 5g, in which the abscissa is the Raman frequency shift in Figures 5a - 5f. It can be seen from Figures 5a - 5g that the sample has several vibrational peaks in the Raman spectrum over the range of test frequencies. The peak signal on the far left (about 1350 cm-1) is the strongest, and is commonly referred to as the D peak in the Raman spectrum of carbon materials, from the vibration of sp2 hybridized carbon atoms. The second strong peak near 1600 cm-1 is called the G peak, and the respiratory vibration from the carbon six-membered ring structure. The third strongest peak near 2700 cm-1 is called the 2D peak, and the overall in-plane vibration from the graphene structure. A weaker peak near 2400 cm-1 is generally considered to be a vibration from the structure of a chain sp2 hybridized carbon atom. For the sake of comparison, the intensity of the D peak is considered to be 1 in each graph, and the other peak intensities are compared with each other to obtain the relative intensity values of the respective Raman vibration peaks. It can be seen that as the magnetic field environment increases (ie, the current increases), the intensity of each high frequency band and the intensity of the D peak are enhanced. In particular, the relative intensity of the chain sp2 hybrid peak increased significantly, while the relative intensity of the G peak and the 2D peak did not increase significantly. This reveals that as the magnetic graphene nanocrystals in the film are magnetized in a magnetic field environment, the high frequency vibration is more pronounced and the signal is enhanced.

Example 2:

Sample: nanocarbon film 2 (amorphous structure); sample thickness: 200 nm; excitation light wavelength: 514 nm; excitation light power: 1 mW. It is found that the Raman spectrum of the amorphous carbon nanofilm is not obvious with the increase of the magnetic field strength. This is because the amorphous nanocarbon film is not magnetic and therefore is not affected by external magnetic fields.

The invention designs a sample stage with a horizontal magnetic field environment for the Raman spectrometer, and realizes the Raman spectroscopy test under the horizontal magnetic field environment. In addition, the strength of the magnetic field in the sample stage can be quickly adjusted by changing the current, or by changing the distance between the first magnet and the second magnet, simplifying the operation in Raman spectroscopy tests requiring different magnetic field strengths. .

The invention provides a Raman spectrometer sample stage and a method for testing the spectrum in situ for providing a horizontal magnetic field environment for a Raman spectrometer, the sample stage comprising: a base; a magnet holder fixed on the base; a first magnet and a second magnet disposed on the magnet holder and correspondingly for generating a horizontal magnetic field; a placement block disposed between the first magnet and the second magnet for placing a sample; the placing Blocks are disposed at intermediate positions of the sample stage, and the magnet holders are respectively located on both sides of the placement block. The sample stage can be placed directly onto the stage of the Raman spectrometer to provide conditions for obtaining Raman spectra of the sample at different magnetic field strengths.

It is to be understood that those skilled in the art can make equivalent substitutions or changes to the inventions and the inventions of the present invention, and all such changes or substitutions fall within the scope of the appended claims.

Claims (10)

A Raman spectrometer sample stage for providing a horizontal magnetic field environment for a Raman spectrometer, the sample stage comprising: a base for supporting the entire sample stage; a magnet holder fixed on the base for supporting the first magnet and the second magnet; Correspondingly arranged to generate a horizontal magnetic field, and the first magnet and the second magnet mounted on the magnet holder; a placement block disposed between the first magnet and the second magnet for placing a sample; The placement block is disposed at an intermediate position of the sample stage, and the magnet holders are respectively located at two sides of the placement block. The Raman spectrometer sample stage according to claim 1, wherein the magnet holder comprises: a first bracket and a second bracket respectively disposed above the two ends of the base, and a third bracket disposed adjacent to the placing block. And a fourth bracket; A groove-shaped sample placement area is formed between the third bracket, the fourth bracket and the placement block. The Raman spectrometer sample stage according to claim 2, wherein the first magnet is an electromagnet or a permanent magnet, and the second magnet is an electromagnet or a permanent magnet. The Raman spectrometer sample stage according to claim 2, wherein the first bracket, the second bracket, the third bracket and the fourth bracket are provided with mounting holes: the mounting holes are used for fixing the electromagnet Both ends, or for placing permanent magnets. The Raman spectrometer sample stage according to claim 2, wherein the sample stage is further provided with a top cover; The top cover is placed above the magnet and the sample, and the top cover is provided with a test port for performing Raman spectroscopy test corresponding to the placement block. The Raman spectrometer sample stage according to any one of claims 2 to 5, characterized in that the magnet holder of the sample stage is further provided with a front side for shielding the magnetic field emitted by the first magnet and the second magnet. Plate, rear side panel, left side panel and right side panel. The Raman spectrometer sample stage according to claim 6, wherein the front side plate or/and the rear side plate are provided with a magnetic field strength test port at a position corresponding to the sample placement area above the placement block. The Raman spectrometer sample stage according to claim 6, wherein the front side panel, the rear side panel, the left side panel, the right side panel, the top cover, and the base constitute the sample stage housing, the sample stage The outer casing has a rectangular parallelepiped shape, a cylindrical shape, or an ellipsoidal shape. The Raman spectrometer sample stage according to claim 8, wherein the first magnet or the second magnet is a cylindrical magnet, a shoe magnet or a rectangular parallelepiped magnet. A method for testing a spectrum in situ by a Raman spectrometer sample stage according to claim 1, comprising the steps of: Step S1: placing the sample stage on the stage of the Raman spectrometer; Step S2, measuring a magnetic field strength of the sample area, and adjusting the magnetic field strength to a predetermined value; Step S3: Obtain Raman spectrum data of the sample under the current magnetic field strength.

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