CN115613143A - Method for preparing nonlinear optical micro-single crystal array without solvent - Google Patents

Abstract

The invention provides a method for preparing a nonlinear optical micro-single crystal array without a solvent, which comprises the following steps of placing a substrate on the upper part of a silicon column template, wherein a raw material groove is arranged on one side of the upper part of the silicon column template, a through hole is arranged on one side of the substrate, and the raw material groove corresponds to the through hole in position; adding the organic micromolecule powder into a raw material groove through a through hole; raising the temperature, wherein when the temperature is higher than the melting point of the small organic molecules, the substrate, the melt of the small organic molecules and the upper surface of the silicon column form a sandwich structure, and the melt flows along the top end of the silicon column under the driving of capillary force until the surface of the whole silicon column template is fully paved; and (3) reducing the temperature, when the temperature is lower than the freezing point of the organic micromolecules, reducing the temperature to room temperature, opening the sandwich structure, and obtaining the nonlinear optical micro-single crystal array on the substrate. The processing precision of the micro single crystal array is controlled by the size of the silicon column, and the precision can reach 1um. Provides a new idea for preparing nonlinear organic microcrystals in an array mode and using the nonlinear organic microcrystals in nonlinear optical and microelectronic circuits.

Description

A solvent-free method for preparing nonlinear optical micro-single crystal arrays

technical field

The invention relates to the field of chemical technology, in particular to a solvent-free method for preparing a nonlinear optical micro-single crystal array.

Background technique

The preparation of organic small molecule microstructures with regular arrangement and excellent single crystallinity is one of the indispensable technologies in the field of manufacturing electronic and optoelectronic components.

In recent years, a variety of solution processing methods have been used to realize the array preparation of organic small molecule materials, such as inkjet printing, micro-imprinting, capillary bridge induction, dipping pen printing and shearing and scraping coating. These methods realize the localized growth process of small organic molecules by arraying microfluidics, so as to precisely control the position and shape of small organic molecules.

However, the organic solvents used in these methods are harmful to the environment, the solubility of small molecules varies greatly in different solvents, and the single crystals of arrays prepared due to the coffee ring effect of solvent volatilization cannot be guaranteed. Methods for molecular single-crystal arrays have significant limitations, in particular, insoluble materials cannot be processed by liquid-phase methods.

Therefore, it is necessary to provide a new universal, simple and efficient method for preparing organic micro-single crystal arrays.

Contents of the invention

The present invention is to solve the problem of preparation of micro-structures of organic small molecules, and provides a solvent-free method for preparing nonlinear optical micro-single crystal arrays. By designing a silicon column template with a micro-column array structure with a special shape, the fluid after melting the small molecules Driven by capillary force, it can flow directionally along the top of the silicon pillar template. After lowering the temperature, the small molecule melt will return from fluid to solid state again, and has good crystallinity, so that the arrangement on the substrate can be regular, the size Controllable small molecule micro-wire arrays are used for second harmonic generation in the field of nonlinear optics.

The invention provides a solvent-free method for preparing a nonlinear optical micro-single crystal array, comprising the following steps:

S1. Place the silicon column template on the test bench, and place the base on the upper part of the silicon column template. The silicon column template is prepared by photolithography and the surface is provided with a periodically repeated structure. The upper side of the silicon column template is provided with a raw material tank. A through hole is set on one side, and the position of the raw material tank corresponds to the position of the through hole;

S2, adding the powder of small organic molecules into the raw material tank through the through hole;

S3. Increase the temperature. When the temperature is higher than the melting point of the small organic molecule and lower than the decomposition temperature, the substrate, the melt of the small organic molecule and the upper surface of the silicon column form a sandwich structure, and the melt is driven by capillary force along the The top of the silicon column flows until it covers the entire surface of the silicon column template;

S4. Lower the temperature. When the temperature is lower than the freezing point of the small organic molecules, then lower the temperature to room temperature, open the sandwich structure, and obtain a nonlinear optical micro-single crystal array on the substrate.

A solvent-free method for preparing a nonlinear optical micro-single crystal array according to the present invention, as a preferred method, in step S1, platforms are set at both ends of the silicon column template, the platforms are located on both sides of the top of the silicon column, and the raw material tank is set on the platform In the middle part, the diameter of the raw material tank is 1-3mm.

A solvent-free method for preparing a non-linear optical micro-single crystal array according to the present invention, as a preferred mode, in step S1, the silicon column is in any of the following shapes: linear, curved, circular, triangular, square and Y shape;

The top of the silicon column is lyophilic and the side is lyophobic.

A solvent-free method for preparing a nonlinear optical micro-single crystal array according to the present invention, as a preferred mode, in step S1, the width of the silicon pillars is 2-100 μm, and the distance between adjacent silicon pillars is 5-100 μm.

A solvent-free method for preparing a nonlinear optical micro-single crystal array according to the present invention, as a preferred method, in step S1, the substrate is any of the following: silicon wafers, silicon dioxide wafers, glass wafers, quartz wafers, oxide Indium tin conductive glass, polyethylene terephthalate, and polyimide.

A method for preparing a nonlinear optical micro-single crystal array without a solvent according to the present invention, as a preferred mode, in step S2, the decomposition temperature of small organic molecules is higher than the melting point temperature.

A solvent-free method for preparing a nonlinear optical micro-single crystal array according to the present invention, as a preferred method, in step S2, the organic small molecule is any of the following: DAT2 small molecules, MLS small molecules, DLS small molecules and OH1 Small molecule.

A method for preparing a nonlinear optical micro-single crystal array without a solvent according to the present invention, as a preferred mode, in step S2, the amount of small organic molecules added is 1-100 mg.

A solvent-free method for preparing a nonlinear optical micro-single crystal array according to the present invention, as a preferred mode, in step S3, the heating temperature is 100-500° C. so that the small organic molecules reach the melting point and become fluid.

A solvent-free method for preparing a nonlinear optical micro-single crystal array according to the present invention, as a preferred method, in step S4, the temperature is slowly lowered to the freezing point of the organic small molecule, and then the temperature is rapidly lowered after the organic small molecule becomes a crystal to room temperature.

A solvent-free method for preparing a nonlinear optical micro-single crystal array, comprising the following steps:

The small molecule powder is added into the small hole of the silicon column template through the small hole on the perforated quartz plate, and the temperature is raised. When the temperature is higher than the melting point of the small molecule, the small molecule will change from solid to liquid. The quartz plate and silicon column and small molecule The melt will form a sandwich structure. Due to the capillary force, the melt flows along the top of the silicon column until it covers the entire silicon column template, and slowly cools down. When the temperature is lower than the freezing point of the small molecule, the small molecule begins to crystallize, and finally on the substrate. A regular array of small molecule micron wire arrays can be obtained, as shown in Figure 1.

The traditional method of preparing single crystal arrays of organic small molecules is generally liquid-phase processing. Small molecules are dissolved in organic solvents to form a solution of a certain concentration, and then liquids are prepared by inkjet printing, scraping, dipping pen printing, etc. Array, as the solvent volatilizes, the concentration of the solution reaches saturation, small molecules begin to nucleate and grow, and finally form an array. However, there are obvious shortcomings in the above methods. The quality of crystals cannot be guaranteed. Most organic solvents are harmful to the body and pollute the environment. Some small molecules have very low solubility. The above liquid phase methods cannot process small molecules that are insoluble in organic solvents. . In the preparation method provided by the present invention, the melting method is used. When the temperature is raised above the melting point of the small molecule, the small molecule will change from solid to liquid, and the quartz plate and silicon column and the small molecule melt will form a sandwich structure. Flow on the top of the silicon column until the entire silicon column template is covered, slowly cool down, the small molecules begin to crystallize, and finally a regular array of micron line arrays of small molecules can be obtained on the substrate, the processing time is also much shorter than that of the liquid phase method, and can Realize the fabrication of large-area small-molecule single-crystal arrays, as shown in Figure 5.

The width of a single column is 2-100 μm, and the distance between adjacent columns is 5-100 μm. There is a large platform at the top of the silicon column for easy drainage, and a small hole with a diameter of 1-3 mm in the middle is used to store solid powder and molten fluid.

Preferably, the small organic molecule requires a decomposition temperature (T _d ) higher than a melting point temperature (T _m ), which is selected from but not limited to one of DAT2, OH1, DLS, and MLS.

Preferably, the mass of the small organic molecule is 1-100 mg.

Preferably, the substrate is selected from one of silicon wafers, silicon dioxide wafers, and quartz wafers.

Preferably, the heating temperature is 100-500° C. to ensure that the small molecules reach the melting point and become fluid. (The heating temperature T is between T _d >T>T _m )

Preferably, the template has a micro-column array structure, wherein the width of a single column is 2-100 μm, the distance between adjacent columns is 5-100 μm, there is a large platform at the top of the silicon column, and a small hole with a diameter of 1-3 mm in the middle, showing As shown in Figure 3.

The present invention has the following advantages:

In the present invention, the small molecule powder is added to the designed hole gap of the silicon column template through the small hole on the quartz, the silicon column template and the quartz sheet form a sandwich structure, the sandwich structure is placed on the heating device, and then the temperature is raised, when the temperature Above the melting point of the small molecules, the melt flows along the top of the silicon pillar until it covers the entire silicon pillar template, and the temperature is lowered slowly. When the temperature is lower than the freezing point of the small molecules, a regularly arranged array of micron wires of small molecules can be obtained on the substrate. Compared with the traditional method of preparing organic small molecule arrays in liquid phase, the quality of crystals is guaranteed, avoiding the damage of organic solvents to the body and the environment, and the array preparation of small molecules that are insoluble in organic solvents can be realized. This preparation method provides a new idea for the array preparation of other small organic molecules and their use in nonlinear optics and microelectronic circuits.

Description of drawings

Fig. 1 is a solvent-free method for preparing nonlinear optical micro-single-crystal arrays in Example 2 of an organic micro-single-crystal array optical microscope;

Fig. 2 is a scanning electron microscope image of a silicon column template structure of a method for preparing a nonlinear optical micro-single crystal array without a solvent;

Fig. 3 is a kind of method sandwich structure schematic diagram of non-solvent preparation nonlinear optical micro-single crystal array;

Fig. 4 is a schematic diagram of the movement process of the molten small molecule fluid during the preparation process of a solvent-free method for preparing nonlinear optical micro-single crystal arrays;

5 is an optical microscope image of a large-area organic micro-single crystal array prepared in Example 2 of a solvent-free method for preparing a nonlinear optical micro-single crystal array;

Figure 6a is a chemical formula structure diagram of a small molecule in Example 2 of a method for preparing a nonlinear optical micro-single crystal array without a solvent;

Figure 6b is a chemical formula structure diagram of small molecules in Example 3 of a method for preparing a nonlinear optical micro-single crystal array without solvent;

Fig. 6c is a chemical formula structure diagram of small molecules in Example 4 of a method for preparing nonlinear optical micro-single crystal array without solvent;

Figure 6d is a chemical formula structure diagram of small molecules in Example 5 of a method for preparing a nonlinear optical micro-single crystal array without a solvent;

FIG. 7 is a diagram of frequency doubling produced by the small molecule single crystal array prepared in Example 2 of a solvent-free method for preparing a nonlinear optical micro-single crystal array at different wavelengths.

detailed description

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, not all of them.

Example 1

A solvent-free method for preparing a nonlinear optical micro-single crystal array, comprising the following steps:

S1, as shown in Figure 3, place the silicon column formwork on the test bench, the base is placed on the upper part of the silicon column formwork, the silicon column formwork is prepared by photolithography and the surface is provided with a periodically repeated structure, the upper part of the silicon column formwork A raw material tank is arranged on the side, and a through hole is arranged on one side of the base, and the position of the raw material tank corresponds to the through hole;

The two ends of the silicon column template are provided with platforms, the platforms are located on both sides of the top of the silicon column, the raw material tank is set in the middle of the platform, and the diameter of the raw material tank is 1-3mm;

As shown in Figure 2, the silicon pillar is any of the following shapes: linear, curved, circular, triangular, square, and Y-shaped; the top of the silicon pillar is lyophilic and the side is lyophobic; the width of the silicon pillar is 2 to 100 μm , the distance between adjacent silicon pillars is 5-100 μm;

The substrate is any one of the following: silicon wafer, silicon dioxide wafer, glass wafer, quartz wafer, indium tin oxide conductive glass, polyethylene terephthalate and polyimide;

S2, adding the powder of small organic molecules into the raw material tank through the through hole;

The decomposition temperature of small organic molecules is higher than the melting point temperature;

Small organic molecules are any of the following: DAT2 small molecules, MLS small molecules, DLS small molecules and OH1 small molecules; the amount of small organic molecules added is 1 to 100 mg;

S3. As shown in Figure 4, increase the temperature. When the temperature is higher than the melting point of the small organic molecule and lower than the decomposition temperature, the substrate, the melt of the small organic molecule and the upper surface of the silicon column form a sandwich structure, and the melt is in the capillary Driven by force, it flows along the top of the silicon column until it covers the entire surface of the silicon column template;

The heating temperature is 100-500°C to make small organic molecules reach the melting point and become fluid;

S4. Slowly lower the temperature to the freezing point of the small organic molecules, then quickly cool down to room temperature after the small organic molecules become crystals, open the sandwich structure, and obtain a nonlinear optical micro-single crystal array on the substrate.

Example 2

A solvent-free method for preparing a nonlinear optical micro-single crystal array, comprising the following steps:

1) Ultrasound the quartz substrate with acetone, ethanol, and isopropanol solutions for ten minutes each, wash it clean, and blow dry it with nitrogen.

2) As shown in Figure 3, the quartz sheet is covered on the silicon column template. The holes on the quartz sheet are aligned with the small holes of the silicon column template below, which is convenient for adding small molecule powder. The silicon column template is 4 μm wide, and the distance between adjacent columns is 20 μm.

3) Add 30mg of DAT2 small molecule powder (molecular formula shown in Figure 6a) into the small hole using a small key.

4) As shown in Figure 4, heat the entire system in the above 3) to 260°C, but pay attention to lower than 293°C, the melting point of DAT2 is 235°C, and the decomposition temperature is 293°C.

5) Keep the above-mentioned system in 4) at 260°C for 5-20min, so that the fluid flows sufficiently to cover the entire surface of the silicon column.

6) Slowly cool down to 200°C, after the fluid completely turns into crystals, quickly cool down to room temperature, disassemble the sandwich system, and the single crystal array is successfully prepared on the quartz substrate, and the silicon column template can be reused.

7) Using femtosecond laser with tunable wavelength as the light source, frequency doubling peaks corresponding to wavelengths from 740nm to 900nm can be observed, as shown in Figure 7, indicating that the prepared micron-line single crystal array is of good quality and can be used for secondary Generation of harmonics.

In this embodiment, through the silicon column template shown in Figure 2, a limited threshold space for directional flow is provided to the molten organic small molecule fluid. After cooling down, the fluid will solidify into a small molecule solid (single crystal) and then obtain A well-arranged array of organic micro-single crystals was obtained, as shown in Figures 1 and 5. At the same time, the crystal quality of the micron wires prepared by the present invention is good, and the size is controllable, and the organic small molecule single crystal array of the corresponding size can be prepared by designing the size of the corresponding template.

Example 3

A solvent-free method for preparing a nonlinear optical micro-single crystal array, comprising the following steps:

1) Ultrasound the quartz substrate with acetone, ethanol, and isopropanol solutions for ten minutes each, wash it clean, and blow dry it with nitrogen.

2) As shown in Figure 3, the quartz sheet is covered on the silicon column template. The holes on the quartz sheet are aligned with the small holes of the silicon column template below, which is convenient for adding small molecule powder. The silicon column template is 4 μm wide, and the distance between adjacent columns is 20 μm.

3) Add 20-30 mg of MLS small molecule powder (molecular formula shown in Figure 6b) into the small hole using a small key.

4) As shown in Figure 4, heat the whole system in the above 3) to 180°C, but pay attention to lower than 253°C, the MLS melting point is 166°C, and the decomposition temperature is 253°C.

5) Keep the above-mentioned system in 4) at 180°C for 5-20 minutes, so that the fluid flows sufficiently to cover the entire surface of the silicon column.

6) Slowly cool down to 140°C, after the fluid completely turns into crystals, quickly cool down to room temperature, disassemble the sandwich system, and the single crystal array is successfully prepared on the quartz substrate, and the silicon column template can be reused.

In this embodiment, through the silicon column template shown in Figure 2, a limited threshold space for directional flow is provided to the molten organic small molecule fluid. After cooling down, the fluid will solidify into a small molecule solid (single crystal) and then obtain A well-arranged organic micro-single crystal array.

Example 4

A solvent-free method for preparing a nonlinear optical micro-single crystal array, comprising the following steps:

1) Ultrasound the quartz substrate with acetone, ethanol, and isopropanol solutions for ten minutes each, wash it clean, and blow dry it with nitrogen.

2) As shown in Figure 3, the quartz sheet is covered on the silicon column template. The holes on the quartz sheet are aligned with the small holes of the silicon column template below, which is convenient for adding small molecule powder. The silicon column template is 4 μm wide, and the distance between adjacent columns is 20 μm.

3) Add 10-30 mg of DLS small molecule powder (molecular formula shown in Figure 6c) into the small hole using a small key.

4) As shown in Figure 4, heat the whole system in the above 3) to 200°C, but pay attention to lower than 253°C, the MLS melting point is 185°C, and the decomposition temperature is 253°C.

5) Keep the system in the above 4) at 200° C. for 5-20 minutes, so that the fluid flows sufficiently to cover the entire surface of the silicon column.

6) Slowly cool down to 160°C. After the fluid completely turns into crystals, quickly cool down to room temperature. The sandwich system is disassembled. The single crystal array is successfully prepared on the quartz substrate, and the silicon column template can be reused.

In this embodiment, through the silicon column template shown in Figure 2, a limited threshold space for directional flow is provided to the molten organic small molecule fluid. After cooling down, the fluid will solidify into a small molecule solid (single crystal) and then obtain A well-arranged organic micro-single crystal array.

Example 5

A solvent-free method for preparing a nonlinear optical micro-single crystal array, comprising the following steps:

1) Ultrasound the quartz substrate with acetone, ethanol, and isopropanol solutions for ten minutes each, wash it clean, and blow dry it with nitrogen.

2) As shown in Figure 3, the quartz sheet is covered on the silicon column template. The holes on the quartz sheet are aligned with the small holes of the silicon column template below, which is convenient for adding small molecule powder. The silicon column template is 4 μm wide, and the distance between adjacent columns is 20 μm.

3) Add 10-30 mg of OH1 small molecule powder (molecular formula shown in Figure 6d) into the small hole using a small key.

4) As shown in Figure 4, heat the entire system in the above 3) to 240°C, but pay attention to lower than 325°C, the melting point of OH1 is 212°C, and the decomposition temperature is 325°C.

5) Keep the system in the above 4) at 240° C. for 5-20 minutes, so that the fluid flows sufficiently to cover the entire surface of the silicon column.

6) Slowly cool down to 180°C, after the fluid completely turns into crystals, quickly cool down to room temperature, disassemble the sandwich system, and the single crystal array is successfully prepared on the quartz substrate, and the silicon column template can be reused.

In this embodiment, through the silicon column template shown in Figure 2, a limited threshold space for directional flow is provided to the molten organic small molecule fluid. After cooling down, the fluid will solidify into a small molecule solid (single crystal) and then obtain A well-arranged organic micro-single crystal array.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto, any person familiar with the technical field within the technical scope disclosed in the present invention, according to the technical solution of the present invention Any equivalent replacement or change of the inventive concepts thereof shall fall within the protection scope of the present invention.

Claims (10)

1. A method for preparing a nonlinear optical micro single crystal array without a solvent is characterized by comprising the following steps: the method comprises the following steps:

s1, placing a silicon column template on an experiment table, placing a substrate on the upper part of the silicon column template, wherein the silicon column template is prepared by a photoetching method and is provided with a periodically repeated structure on the surface, one side of the upper part of the silicon column template is provided with a raw material groove, one side of the substrate is provided with a through hole, and the raw material groove corresponds to the through hole in position;

s2, adding organic micromolecule powder into the raw material groove through the through hole;

s3, raising the temperature, wherein when the temperature is higher than the melting point of the small organic molecules and lower than the decomposition temperature, the substrate, the melt of the small organic molecules and the upper surface of the silicon column form a sandwich structure, and the melt flows along the top end of the silicon column template under the driving of capillary force until the surface of the whole silicon column template is fully paved;

and S4, reducing the temperature to room temperature when the temperature is lower than the freezing point of the organic micromolecules, opening the sandwich structure, and obtaining the nonlinear optical micro-single crystal array on the substrate.

2. The method for the solvent-free preparation of nonlinear optical micro single crystal arrays according to claim 1, wherein: in the step S1, platforms are arranged at two ends of the silicon column template, the platforms are positioned at two sides of the top of the silicon column, the raw material groove is arranged in the middle of the platforms, and the diameter of the raw material groove is 1-3 mm.

3. The method for the solvent-free preparation of nonlinear optical micro single crystal arrays according to claim 1, wherein: in step S1, the silicon pillar is in any one of the following shapes: linear, curved, circular, triangular, square and Y-shaped;

the top end of the silicon column is lyophilic and the side part is lyophobic.

4. The method for the solvent-free preparation of nonlinear optical micro single crystal arrays according to claim 1, wherein: in step S1, the width of the silicon pillars is 2-100 μm, and the distance between adjacent silicon pillars is 5-100 μm.

5. The method for the solvent-free preparation of nonlinear optical micro single crystal arrays according to claim 1, wherein: in step S1, the substrate is any one of the following: silicon wafer, silicon dioxide sheet, glass sheet, quartz sheet, indium tin oxide conductive glass, polyethylene terephthalate and polyimide.

6. The method for the solventless preparation of a nonlinear optical micro single crystal array according to claim 1, wherein: in step S2, the decomposition temperature of the small organic molecules is higher than the melting point temperature.

7. The method for the solventless preparation of nonlinear optical micro single crystal arrays according to claim 6, wherein: in step S2, the organic small molecule is any one of the following: DAT2, MLS, DLS and OH1 small molecules.

8. The method for the solvent-free preparation of nonlinear optical micro single crystal arrays according to claim 1, wherein: in the step S2, the addition amount of the small organic molecules is 1-100mg.

9. The method for the solventless preparation of a nonlinear optical micro single crystal array according to claim 1, wherein: in step S3, the heating temperature is 100-500 ℃ to make the organic small molecules reach the melting point and become fluid.

10. The method for the solvent-free preparation of nonlinear optical micro single crystal arrays according to claim 1, wherein: in step S4, the temperature is slowly reduced to the solidifying point of the organic micromolecules, and the temperature is quickly reduced to the room temperature after the organic micromolecules are changed into crystals.

Images