CN108365096A - The block copolymer semiconductor nanowires preparation method and its usage of helical structure - Google Patents

Abstract

The invention discloses a method for preparing a helical structure block copolymer semiconductor nanowire and its application. The block copolymer semiconductor material and the polymer insulation material are respectively dissolved in a solvent and then mixed to form a blend solution. By controlling the block The mass ratio of the copolymer semiconductor material and the polymer insulating material can obtain block copolymer semiconductor nanowires with different densities and diameters of helical structures. The block copolymer semiconductor nanowire of the present invention can be used as the semiconductor layer of an organic field-effect transistor ammonia sensor, which can improve the sensitivity of ammonia sensing and reduce the detection limit, and the nanowire can be changed only by changing the preparation process conditions. density and diameter. The present invention firstly prepares the block copolymer semiconductor nanowire with helical structure through the blending method, applies it to ammonia sensing and obtains higher sensing performance.

Description

Preparation method and application of helical block copolymer semiconductor nanowires

technical field

The invention relates to the field of organic semiconductor nanostructures and devices, in particular to a method for preparing a helical-structured block copolymer semiconductor nanowire and its application.

Background technique

Ammonia (NH3), as an important chemical raw material, is widely used in industrial production, food storage, safety requirements and other fields. Due to the strong toxicity of ammonia gas, when the human body is exposed to a low-concentration ammonia environment, it can produce poisoning symptoms such as edema in the respiratory tract and gastric mucosa. Therefore, it is very important to prepare an ammonia sensor with high sensitivity, low detection limit and stable performance.

Conjugated polymer organic field effect transistors have received extensive attention and research in recent years due to their potential advantages such as large-area solution processing, flexible devices, and low cost. The organic field effect transistor device has the characteristics of signal amplification. It has good detection and recording functions for extremely small current values and changes. It can sensitively detect the current changes between the source and drain electrodes of the device due to the action of ammonia gas. Recovery and repeated testing after detection; Conjugated polymer organic semiconductors have strong plasticity in molecular structure, and the sensing characteristics can be reasonably adjusted through the design of molecular structure, so as to improve the specificity of functional materials to be tested in a targeted manner identify.

Nanowires generally refer to wires with diameters between 1-100 nanometers. When the special microstructure of nanowires is used to prepare the active layer of organic field effect transistors, the amount of material used in the device is small, the specific surface area is large, and the molecular arrangement is regular and the electrical performance is high. The active layer of a gas sensor with a nanowire structure has the advantages of high responsivity, good sensitivity, and fast response recovery. The helical structure of the polymer is mainly a special supramolecular structure formed by the self-assembly of the polymer chain induced by the π-π interaction generated by the electrons in the molecule. This structure has a wide range of applications in optical and biological detection. , however, there is no application in gas sensing at present.

The currently known organic field effect transistors based on block copolymer semiconductor nanowires have not been reported for gas sensing. In addition, the regulation of block copolymer morphology usually requires changing the molecular weight or block ratio of the copolymer. It is difficult to adjust the molecular chain from the polymerization level, and there is no report on regulating the morphology (density, diameter) of nanowires only through the preparation conditions of nanowires.

Contents of the invention

The purpose of the present invention is to provide a method for preparing a helical structure block copolymer semiconductor nanowire and its application. The technical problem to be solved is how to use the interaction within the molecular structure to form a helical structure and regulate the block copolymer nanowire Morphology, and its application in organic field-effect transistor gas sensors.

In order to achieve the above object, the technical scheme adopted in the present invention is:

A method for preparing a helical block copolymer semiconductor nanowire, characterized in that it comprises the following steps:

(1), the block copolymer semiconductor material and the polymer insulating material are respectively dissolved in respective organic solvents, and then mixed to form a blend solution, the mass ratio of the block copolymer semiconductor material and the polymer insulating material in the blend solution is 1:80-1:40;

(2), spin-coat the blended solution obtained in step (1) on the substrate, and then vacuumize to remove the remaining solvent, so as to form a composite layer on the substrate with the polymer insulating material as the bottom layer and the block copolymer semiconductor material as the top layer. double layer film;

(3), soak the double-layer film formed on the substrate in the medium, separate the double-layer film from the substrate and float on the surface of the transition solution, then use the substrate to put into the transition solution to contact with the surface of the double-layer film, and place the double-layer film Flip and pull out, so as to form an inverted double-layer film on the substrate with the block copolymer semiconductor material as the bottom layer and the polymer insulating material as the top layer;

(4), using orthogonal solvent soaking step (3) to obtain the inverted double-layer film, the insulating material is dissolved in the orthogonal solvent to remove the polymer insulating material, that is, to obtain a block copolymer semiconductor nanowire, and the block Copolymer semiconductor nanowires form a helical structure due to the self-assembly properties of self-insulating segments.

The preparation method of the block copolymer semiconductor nanowire of the helical structure is characterized in that: the density and diameter of the block copolymer semiconductor nanowire obtained in the step (4) are determined by the block copolymer in the blending solution in the step (1). The mass ratio of the copolymer semiconductor material and the polymer insulating material is determined. The mass ratio of the block copolymer semiconductor material and the polymer insulating material in the blend solution is between 1:80-1:40. The larger the mass ratio, the final The block copolymer semiconductor nanowires are denser and larger in diameter.

The preparation method of the block copolymer semiconductor nanowire of the helical structure is characterized in that: when the mass ratio of the block copolymer semiconductor material and the polymer insulating material in the blend solution in step (1) is 1:40, the step ( 4) Block copolymer semiconductor nanowires forming a microsphere structure.

The preparation method of the block copolymer semiconductor nanowire of the helical structure is characterized in that: the block copolymer semiconductor material in the step (1) is poly (4-isocyano-benzoic acid 5-(2-dimethyl (amino-ethoxy)-2-nitro-benzyl ester-b-poly(3-hexylthiophene), namely PPI(-DMAENBA)-b-P3HT), or polyphenylisocyanate-b-poly (3-hexylthiophene), that is, PPI-b-P3HT;

The polymer insulating material in the step (1) is polymethyl methacrylate, i.e. PMMA;

The organic solvent in the step (1) is selected from chlorobenzene or o-dichlorobenzene.

The preparation method of the helical block copolymer semiconductor nanowire is characterized in that: in step (1), the block copolymer semiconductor material is dissolved in an organic solvent to form a solution A, and the polymer insulating material is dissolved in the same organic solvent. Solution B is formed in the solvent; then solution A and solution B are mixed evenly to obtain a blended solution;

The concentration of the block copolymer semiconductor material in the solution A is 0.5-1mg/mL, and the concentration of the polymer insulating material in the solution B is 130mg/mL; When applied, the polymer insulating material and the block copolymer semiconducting material are layered.

The method for preparing the helical structure block copolymer semiconductor nanowire is characterized in that the spin coating speed in step (2) is 2000rmp.

The method for preparing the helical-structured block copolymer semiconductor nanowire is characterized in that the transition solution in step (3) is potassium hydroxide aqueous solution.

The method for preparing the helical structure block copolymer semiconductor nanowire is characterized in that: in step (4), the orthogonal solvent is acetone or ethyl acetate.

The method for preparing a block copolymer semiconductor nanowire with a helical structure is characterized in that: in step (4), the helical structure is formed by the self-assembly characteristics of the insulating segment of the block copolymer semiconductor nanowire, that is, the block copolymer semiconductor nanowire The insulating segment of the wire forms a helical structure through strong π-electron interaction, and as long as the insulating segment can generate strong intramolecular π-electron interaction, the nanowire with a helical structure can be obtained.

The purposes of the block copolymer semiconductor nanowire of helical structure, it is characterized in that: as the semiconductive layer of organic field effect transistor ammonia gas sensor, based on the helical structure of block copolymer semiconductor nanowire and the functional group on the side group to ammonia gas The specific adsorption capacity improves the sensing sensitivity of the organic field effect transistor ammonia sensor and reduces the detection limit.

Compared with the prior art, the beneficial effects of the present invention are reflected in:

1. The present invention applies block copolymer semiconductors to organic field effect transistor sensors for the first time.

2. The present invention realizes for the first time that the density, diameter and length of block copolymer nanowires are regulated by using process conditions.

3. The present invention uses the polymer blend system solution method to prepare block copolymer nanowires and organic field effect transistor sensors based on it, which has the advantages of simple operation, good repeatability, low requirements for equipment and process conditions, and does not require the use of large Advantages of precision instruments and equipment.

4. The field effect transistor sensor prepared by the method of the present invention has the advantages of high sensitivity, good selectivity, low detection limit and stable performance due to the large specific surface area and thin thickness of the active layer. It has important application prospects.

Description of drawings

Figure 1a) is the molecular structural formula of PPI(-DMAENBA)-b-P3HT, and b) is the molecular structural formula of PPI-b-P3HT.

Fig. 2 is an atomic force microscope picture (left) and a transmission electron microscope picture (right) of the PPI(-DMAENBA)-b-P3HT nanowire obtained in the example.

Figures 3a, 3b, and 3c show the morphology of block copolymer nanowires obtained by mass ratios of block copolymer semiconductor material and polymer insulating material at 1:80, 1:60, and 1:40, respectively.

Fig. 4 is the structural representation of the PPI (-DMAENBA)-b-P3HT nanowire organic field-effect transistor sensor that embodiment gains.

Fig. 5 is the transfer curve and the output curve of the PPI (-DMAENBA)-b-P3HT nanowire organic field effect transistor sensor obtained in the embodiment, the solid line and the dotted line in the output curve are respectively based on block copolymer semiconductor material and polymer insulation Output curves of organic field-effect transistors of nanowires with material mass ratios of 1:40 and 1:80.

Detailed ways

The embodiments of the present invention are described in detail below. This embodiment is implemented on the premise of the technical solution of the present invention, and detailed implementation methods and specific operating procedures are provided, but the protection scope of the present invention is not limited to the following implementation example.

Example 1

The present embodiment prepares PPI (-DMAENBA)-b-P3HT nanowire and organic field effect transistor sensor based on it as follows:

(1) PPI(-DMAENBA)-b-P3HT is dissolved in o-dichlorobenzene to form a solution A with a concentration of 2mg/mL, and PMMA is dissolved in chlorobenzene to form a solution B with a concentration of 130mg/mL; Mix well with solution B to form a blend solution, in which the mass ratio of PPI(-DMAENBA)-b-P3HT to PMMA is 1:80, or 1:60, or 1:40. The molecular structural formulas of PPI(-DMAENBA)-b-P3HT and PPI-b-P3HT are shown in Figure 1.

(2) The n-type silicon wafer is cleaned as a substrate after being heated in a concentrated sulfuric acid-hydrogen peroxide mixed solution; by the spin coating method, the blended solution is spin-coated on the substrate at a speed of 2000 rpm and vacuum-dried at room temperature for 12 hours, thereby On the substrate, a double-layer film with PMMA film as the bottom layer and PPI(-DMAENBA)-b-P3HT nanowire as the top layer is formed;

(3) Take a silicon wafer with silicon dioxide on the surface (and use poly(2,3-bis(difluoromethyl)-2,3,4,4,5,5-cyclohexafluorotetrahydrofuran for the surface silicon dioxide) ) Cytop for modification) as a substrate, the double-layer film was floated in a potassium hydroxide solution with a mass concentration of 5%, and then pulled out by flipping the substrate to form a PPI(-DMAENBA)-b- P3HT nanowires as the bottom layer and PMMA film as the top layer flip double-layer film; washing with ethyl acetate to remove the PMMA film, that is, to obtain PPI(-DMAENBA)-b-P3HT nanowires.

Fig. 2 is the atomic force microscope picture of the obtained PPI (-DMAENBA)-b-P3HT nanowire of the present embodiment, as can be seen from the figure, the uniformly distributed nanowire thickness is formed at about 10 nanometers, and when the mass ratio is from 1: When 80 becomes 1:60, the density of nanowires increases significantly, and the diameter of nanowires increases from 35-55 nanometers to 40-65 nanometers; when the mass ratio changes from 1:60 to 1:40, nanowires become Spherical structures linked to each other by nanowires, the diameter of which has also been reduced to 20-40 nanometers.

(4) Gold electrodes were evaporated on the ultra-thin film as the source and drain electrodes, the channel length and width were 80 μm and 1000 μm, respectively, and the substrate silicon was used as the gate, that is, the PPI(-DMAENBA)-b-P3HT nanowires were obtained. The structure of the airport effect transistor sensor is shown in Figure 3.

Test the response curve of the present embodiment gained PPI (-DMAENBA)-b-P3HT nanowire organic field effect transistor sensor to ammonia as follows:

Keithley 4200 semiconductor device analyzer was used to test the electrical performance of the device, and the transfer curve (V _D =-80V) and output curve of the device were obtained. The results are shown in FIG. 4 .

A flow meter is used to control the flow rate of ammonia gas, and ammonia gas and compressed air are sequentially fed into the channel of the device to test the gas sensing characteristics of the device for ammonia gas. The result is shown in Figure 5 (the ordinate in Figure 5 is the ratio of ΔI/I(0) current variation, that is: ), the calculated sensor sensitivity is very high, which is 68%; and the response recovery speed of the sensor is fast, the response time and recovery time are 4.87s and 55.14s respectively.

The above are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention. Inside.

Example 2

In this embodiment, helical structure nanowires and organic field effect transistor sensors based on the same method as in Example 1 were prepared, the only difference being that PPI(-DMAENBA)-b-P3HT was replaced with PPI-b-P3HT. The properties of the obtained helical nanowires and sensors are similar to those of Example 1.

Claims (10)

1. the block copolymer semiconductor nanowires preparation method of helical structure, it is characterised in that：Include the following steps：

（1）, block copolymer semi-conducting material and insulating material of polymer be dissolved in respectively in respective organic solvent, remix Blend solution is formed, the mass ratio of block copolymer semi-conducting material and insulating material of polymer is 1 in blend solution:80-1: 40；

（2）, by step（1）Obtained blend solution is spin-coated in substrate, then vacuumizes removal residual solvent, in substrate It is upper to be formed using insulating material of polymer as bottom, using block copolymer semi-conducting material as the bilayer film of top layer；

（3）, the bilayer film formed in substrate is soaked in, so that duplicature is detached with substrate and swim in transition solution table Then face is put into transition solution using substrate and is contacted with the double-deck film surface, bilayer film overturning is pulled out, on substrate It is formed using block copolymer semi-conducting material as bottom, using insulating material of polymer as the overturning bilayer film of top layer；

（4）, using orthogonal solvents soaking step（3）Obtained overturning bilayer film, makes insulating materials be dissolved in orthogonal solvents, To remove insulating material of polymer, that is, obtain block copolymer semiconductor nanowires, and block copolymer semiconductor nanowires by Helical structure is formed in the self assembly characteristic of itself insulating segment.

2. the block copolymer semiconductor nanowires preparation method of helical structure according to claim 1, it is characterised in that： Step（4）In the obtained density and diameter of block copolymer semiconductor nanowires, by step（1）Block is total in middle blend solution The mass ratio of polymers semi-conducting material and insulating material of polymer determines, block copolymer semi-conducting material and poly- in blend solution The mass ratio of object insulating materials is closed 1:80-1:Between 40, the mass ratio the big, and finally obtained block copolymer semiconductor is received Rice noodles density is bigger, diameter is bigger.

3. the block copolymer semiconductor nanowires preparation method of helical structure according to claim 1 or 2, feature exist In：Step（1）The mass ratio of block copolymer semi-conducting material and insulating material of polymer is 1 in middle blend solution:When 40, step Suddenly（4）Form the block copolymer semiconductor nanowires of micro-sphere structure.

4. the block copolymer semiconductor nanowires preparation method of helical structure according to claim 1, it is characterised in that： Step（1）In block copolymer semi-conducting material be poly-（4- isocyano groups-benzoic acid 5-（2- Dimethylamino-ethoxies）-2- Nitro-benzyl ester-b- is poly-（3- hexyl thiophenes）, i.e. PPI (- DMAENBA)-b-P3HT), or it is poly- for polyphenylene isocyanide-b-（3- Hexyl thiophene）, i.e. PPI-b-P3HT；

Step（1）In insulating material of polymer be polymethyl methacrylate, i.e. PMMA；

Step（1）In organic solvent selection chlorobenzene or o-dichlorohenzene.

5. the block copolymer semiconductor nanowires preparation method of helical structure according to claim 1, it is characterised in that： Step（1）In, the dissolving of block copolymer semi-conducting material forms solution A in organic solvent, and insulating material of polymer is dissolved in Solution B is formed in identical organic solvent；Solution A and solution B are uniformly mixed to get to blend solution again；

A concentration of 0.5-1mg/mL of block copolymer semi-conducting material in solution A, the concentration of insulating material of polymer in solution B For 130 mg/mL；It, can be in step by controlling the mass ratio of solution A and solution B（2）Make insulating material of polymer when spin coating It is layered with block copolymer semi-conducting material.

6. the block copolymer semiconductor nanowires preparation method of helical structure according to claim 1, it is characterised in that： Step（2）Middle spin speed is 2000rmp.

7. the block copolymer semiconductor nanowires preparation method of helical structure according to claim 1, it is characterised in that： Step（3）Middle transition solution is potassium hydroxide aqueous solution.

8. the block copolymer semiconductor nanowires preparation method of helical structure according to claim 1, it is characterised in that： Step（4）Middle orthogonal solvents are acetone or ethyl acetate.

9. the block copolymer semiconductor nanowires preparation method of helical structure according to claim 1, it is characterised in that： Step（4）Middle helical structure is formed by the self assembly characteristic of block copolymer semiconductor nanowires insulating segment, i.e. block copolymer The insulating segment of semiconductor nanowires interacts to form helical structure by strong pi-electron, as long as insulating segment can generate by force Strong intramolecular pi-electron interaction can be obtained the nano wire of helical structure.

10. the purposes of the block copolymer semiconductor nanowires of helical structure, it is characterised in that：As organic field effect tube The semiconductor layer of ammonia gas sensor, the functional group pair on helical structure and its side group based on block copolymer semiconductor nanowires The specific adsorption ability of ammonia promotes the sensing sensitivity of organic field effect tube ammonia gas sensor, reduces detection limit.