A method for constructing a channel array on a flexible film surface, a flexible film with a channel array, and applications thereof

Abstract

The application discloses a method for constructing a channel array on a flexible film surface, a flexible film with the channel array and application of the flexible film. The method for constructing the channel array on the flexible film surface comprises the following steps: taking a template with a channel array, copying the channel array on the template to a surface of a flexible film to be processed through hot stamping, and thus constructing the channel array on the surface of the flexible film. The channel array on the template is copied to the flexible film through the hot stamping technology, the flexible film is easy to be peeled off from the template, and the flexible film is not prone to breakage or tearing. The channel array obtained on the flexible film is clear, complete and accurate to the nanometer level, and the flexible film has wide application range and high practicability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of nanomaterials, and in particular to a method for constructing a channel array on a flexible film surface, a flexible film with a channel array and application thereof. BACKGROUND

[0002] There are two kinds of film materials for optoelectronic devices, rigid materials and flexible materials, and the flexible materials are mainly polymers, such as polyimide (PI) film, polydimethylsiloxane (PDMS) film, polyethylene terephthalate (PET) film and polyethylene naphthalate (PEN) film. In the past ten years, through the in-depth research of researchers on flexible devices, the flexible devices not only have many characteristics (bendable, foldable, stretchable, and can maintain excellent performance under deformation) that traditional electronic products cannot achieve, but also open up a bright prospect for the development of flexible solar cells, wearable electronic devices, electronic skin and flexible photodetectors, for example, a flexible photodetector based on nanowire array, because the one-dimensional nanowire material has a high specific surface area, which helps to enhance the separation and collection of carriers, and when the nanowire array and the flexible film are constructed into a photodetector, it has mechanical flexibility and excellent photoelectric performance. The application of flexible devices not only can improve our quality of life, but also will eventually change our way of life.

[0003] Because the channel array on the substrate surface plays an important guiding role in the growth of nanowires, the construction of the channel array on the flexible film surface is a research hotspot in recent years. At present, the method for constructing the channel array on the flexible film surface includes the following steps: a micro-channel array is prepared on a silicon substrate by a micro-processing method, the substrate with the micro-channel array is assembled into a mold bottom plate, a polymerizable liquid raw material is added to the surface of the substrate, and after polymerization, a strong hydrophobic flexible film is obtained through chemical grafting treatment, and the substrate and the flexible film are separated to obtain a flexible film with a micro-channel array. Because the flexible film is directly prepared on the substrate by polymerization reaction in this preparation method, it is not easy to peel off from the substrate, and the mechanical peeling causes great damage to the surface of the film, resulting in incomplete and many surface defects of the replicated channel array. SUMMARY

[0004] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application provides a method for constructing a channel array on a flexible film surface, and the flexible film surface prepared by the method has a complete nanochannel array and a simple operation process.

[0005] The present application also provides a flexible film with a channel array on the surface prepared by the above method.

[0006] The present application also provides the application of the flexible film with the channel array on the surface.

[0007] The present invention also provides a photoelectric device comprising the flexible film with the channel array on its surface.

[0008] The present invention also proposes a method for preparing a photoelectric device, which includes processing a flexible film: constructing a channel array on the surface of the flexible film by the above method.

[0009] In a first aspect of the present invention, a method for constructing a channel array on a flexible film surface is proposed, comprising the following steps: taking a template with a channel array, and replicating the channel array on the template to the surface of a flexible film to be processed by hot embossing, thereby constructing a channel array on the flexible film surface.

[0010] A method for constructing a channel array on the surface of a flexible film according to an embodiment of the present invention has at least the following beneficial effects: the present invention uses hot embossing technology to copy the channel array on the template onto the flexible film. The flexible film is easy to peel off from the template, is not easily damaged or torn, and is not easily introduced into the flexible film by other impurities. At the same time, the channel array obtained on the flexible film is clear and complete, with nanometer-level precision, and has a wide range of applications and high practicality.

[0011] The present invention has low cost and simple process. A low-cost small mechanical press can be used. Through a simple process, the template's channel array can be batch-copied onto a variety of flexible films (flexible substrates). In addition, by simply replacing different channel templates, different nanochannel arrays (such as different cross-sections, different channel widths, different channel spacings, and different array patterns, etc.) can be quickly constructed on the surfaces of various polymer flexible films (flexible substrates), allowing for large-scale production while ensuring pattern accuracy.

[0012] The present invention has universal applicability, specifically: 1. By selecting appropriate parameters (hot embossing temperature and pressure), nanoscale channel arrays can be quickly replicated on different polymer flexible films (flexible substrates), and the replicated array area is controllable; 2. Using the same template, the nanochannels obtained on various polymer flexible films are almost identical, and the shape and size of the channels are completely determined by the template used. Therefore, in principle, different channels can be obtained on the flexible film simply by changing the template.

[0013] The flexible film with a nanochannel array on the surface prepared by the present invention can provide a flexible substrate for the growth of in-plane arrays of organic nanowires, and can be applied to flexible optoelectronic devices of organic nanowire arrays. Flexible optoelectronic devices can be bent, folded, twisted, compressed, stretched, and even deformed into any shape while still maintaining high-efficiency optoelectronic performance, reliability and integration, such as: diodes (including organic light-emitting diodes), transistors, field-effect transistors, photodetectors, flexible nanogenerators, etc.

[0014] In some embodiments of the present invention, the template has a channel array on a side facing the flexible film.

[0015] In some embodiments of the present invention, the channel array on the flexible film having a channel array on its surface is a "V"-shaped nanochannel array, the angle between adjacent channel components is 100-140°, the spacing between adjacent channels is 50-150 nm, and the channel depth is 10-30 nm.

[0016] In some embodiments of the present invention, the hot embossing process includes heating the flexible film to be processed until the film is in a highly elastic state, applying pressure and maintaining the pressure for a period of time, and cooling the film.

[0017] In some embodiments of the present invention, the hot embossing process includes heating to a temperature T1, pressurizing to a pressure P and maintaining for a time t, and cooling to a temperature T2, wherein T1>0°C and T2>0°C.

[0018] Through the above embodiment, a hot embossing device (such as a sheet press) is used to first heat the flexible film to an appropriate temperature T1 (generally above the glass transition temperature of the flexible film) and maintain it constant. At this time, the film is in a highly elastic state. Then, pressure is applied and maintained for an appropriate time to allow the film to fully fill the grooves of the template. It is then cooled to T2 (generally below the glass transition temperature of the flexible film) and then unloaded. Nanoscale channel arrays can be prepared on the flexible film.

[0019] The present invention has universality: by selecting appropriate parameters (hot embossing temperature and pressure), nanoscale channel arrays can be quickly replicated on different polymer flexible films.

[0020] In some preferred embodiments of the present invention, the temperature is raised to temperature T1, and pressurization is started after the temperature stabilizes.

[0021] In some preferred embodiments of the present invention, the glass transition temperature of the flexible film to be treated is less than T1 and less than the melting point of the flexible film.

[0022] In some preferred embodiments of the present invention, T2 is less than the glass transition temperature of the flexible film.

[0023] In some more preferred embodiments of the present invention, 40°C≤T1≤250°C, and 0°C<T2≤200°C.

[0024] In some more preferred embodiments of the present invention, 50°C≤T1≤230°C, 50°C≤T2≤180°C.

[0025] In some preferred embodiments of the present invention, P=50-300 MPa.

[0026] In some preferred embodiments of the present invention, the t=1-5 h.

[0027] In some preferred embodiments of the present invention, the t=2-5 h.

[0028] Through the above-described embodiment, in a hot embossing device (such as a sheet press), the flexible film is heated to above its glass transition temperature (Tg), allowing the polymer macromolecular segments to fully move, resulting in a highly elastic state in the film, which can deform under a certain pressure. Applying pressure forces the film to fill the grooves of the template, maintaining the film for a suitable time to fully fill the grooves. The film is then cooled to below its Tg, solidifying the pattern.

[0029] In some embodiments of the present invention, the method includes placing the flexible film to be processed into a sandwich of the template to obtain a laminated structure, and performing a hot embossing process on the laminated structure.

[0030] The method comprises placing the flexible film to be processed into the interlayer of the template to obtain a "sandwich" structure, that is, a laminated structure, and performing a hot embossing process on the "sandwich" structure.

[0031] In some embodiments of the present invention, the method comprises: placing the flexible film to be processed in a sandwich between two templates to obtain a laminated structure, and performing a hot embossing process on the laminated structure.

[0032] In some embodiments of the present invention, the method includes placing the flexible film to be processed in a sandwich between two templates to obtain a "sandwich" structure, and performing a hot embossing process on the "sandwich" structure.

[0033] The above-mentioned "sandwich" structure, where a flexible film is sandwiched between two templates, allows the film to be easily peeled off after hot embossing, facilitating the complete fabrication of the channel array on the flexible film. However, when hot embossing using only one template and one flexible film, the film can easily stick to the heating plate of the hot embossing equipment if the required heating temperature is high, and the film can easily tear if forcibly peeled off.

[0034] In some embodiments of the present invention, the template is a hot stamping resistant template.

[0035] In some embodiments of the present invention, the template comprises M-face sapphire.

[0036] In some embodiments of the present invention, the template comprises annealed M-plane sapphire.

[0037] Through the above embodiment, the surface of the M-plane sapphire has The periodic array of "V"-shaped channels in the direction is specifically made of annealed M-plane sapphire (i.e. α-Al2O3, crystal plane orientation ) single crystal wafer as a template, its surface has The "V"-shaped nanoscale channel arrays are arranged in a 100-140° angle between adjacent channels, with a spacing of 50-150 nm between adjacent channels and a channel depth of 10-30 nm. Furthermore, M-plane sapphire exhibits high hardness and mechanical strength, capable of withstanding the high pressures required for hot embossing and allowing for repeated use. However, hot embossing silicon wafers with micro-nanochannel arrays on their surfaces is highly likely to break.

[0038] The present invention only needs to subject the M-plane sapphire to high-temperature annealing to obtain a sapphire template with a "V"-shaped nanoscale channel array on the surface. Compared with the use of micromachining methods to prepare microchannel array templates, the present invention improves the channel array precision to the nanoscale. Compared with other methods for preparing nanoscale channel templates, it has the obvious advantages of low cost and simple process. Moreover, large-scale replication of nanochannels can be achieved simply by increasing the size of the template and the flexible film in proportion.

[0039] In some preferred embodiments of the present invention, the surface of the M-face sapphire has The invention discloses a V-shaped nanoscale channel array in the direction of the nanometer-level channel array, wherein the angle between adjacent channel components of the channel array is 100-140 degrees, the spacing between adjacent channels is 50-150 nm, and the channel depth is 10-30 nm.

[0040] In some more preferred embodiments of the present invention, the M-plane sapphire is an M-plane sapphire single crystal wafer.

[0041] In some preferred embodiments of the present invention, the annealing process of the M-plane sapphire includes: heating to 1550-1650° C. at a rate of 8-12° C. / min, maintaining the temperature for 9-11 hours, and cooling to room temperature.

[0042] In some more preferred embodiments of the present invention, the annealing process includes: placing the M-plane sapphire in a high-temperature box furnace, raising the temperature to 1550-1650°C at a rate of 8-12°C / min, maintaining the temperature for 9-11 hours, and cooling to room temperature.

[0043] In some more preferred embodiments of the present invention, the annealing process includes: raising the temperature to about 1600° C. at a rate of about 10° C. / min, maintaining the temperature for about 10 h, and cooling to room temperature.

[0044] In some more preferable embodiments of the present application, the annealing process comprises: placing the M-plane sapphire into a high-temperature box furnace, increasing the temperature to about 1600 ℃ at a rate of about 10 ℃ / min, keeping the temperature constant for about 10 h, and cooling to room temperature.

[0045] In some more preferable embodiments of the present application, the cooling mode is furnace cooling.

[0046] In some preferable embodiments of the present application, the M-plane sapphire is pre-cleaned before the annealing process.

[0047] In some more preferable embodiments of the present application, the pre-cleaning of the M-plane sapphire comprises: ultrasonic cleaning the M-plane sapphire with acetone.

[0048] In the above embodiments, the ultrasonic cleaning with acetone removes oil stains on the surface of the sapphire, and the surface is dried with dry nitrogen to remove residual organic solvents.

[0049] In some more preferable embodiments of the present application, the pre-cleaning of the M-plane sapphire comprises: ultrasonic cleaning the M-plane sapphire with acetone, and drying with nitrogen.

[0050] In some preferable embodiments of the present application, the M-plane sapphire after the annealing process is cleaned again before the flexible film is placed in the interlayer between the templates.

[0051] In some more preferable embodiments of the present application, the re-cleaning of the M-plane sapphire comprises: ultrasonic cleaning the M-plane sapphire with ethanol, acetone, ethanol, water, and ethanol in sequence.

[0052] In the above embodiments, the ultrasonic cleaning removes oil stains and impurities on the surface, and the nitrogen gun is used for nitrogen drying.

[0053] In some more preferable embodiments of the present application, in the re-cleaning of the M-plane sapphire, the M-plane sapphire is ultrasonically cleaned with ethanol, acetone, ethanol, water, and ethanol in sequence for 5-15 min.

[0054] In some more preferable embodiments of the present application, in the re-cleaning of the M-plane sapphire, the M-plane sapphire is ultrasonically cleaned with ethanol, acetone, ethanol, distilled water, and ethanol in sequence for 10 min.

[0055] In some embodiments of the present application, the flexible film comprises a polymer flexible material.

[0056] In some preferable embodiments of the present application, the polymer flexible material comprises at least one of PI, PET, or PEN.

[0057] Among them, PI: polyimide; PDMS: polydimethylsiloxane; PET: polyethylene terephthalate; PEN: polyethylene naphthalate.

[0058] In some more preferred embodiments of the present invention, the flexible film is a PI film, 220°C≤T1≤230°C, 150 MPa≤P≤200 MPa.

[0059] In some embodiments of the present invention, the flexible film is cleaned before hot embossing.

[0060] In some embodiments of the present invention, the flexible film is cleaned before being placed in the sandwich between the templates before hot stamping.

[0061] In some preferred embodiments of the present invention, the film cleaning process includes cleaning the flexible film with ethanol, acetone, ethanol, water, and ethanol in sequence.

[0062] In some more preferred embodiments of the present invention, the film cleaning process includes ultrasonically cleaning the flexible film with ethanol, acetone, ethanol, water, and ethanol in sequence for 5-10 minutes.

[0063] In some more preferred embodiments of the present invention, the film cleaning process includes ultrasonically cleaning the flexible film with ethanol, acetone, ethanol, water, and ethanol in sequence for about 5 minutes.

[0064] In some more preferred embodiments of the present invention, the film cleaning process includes ultrasonically cleaning the flexible film with ethanol, acetone, ethanol, distilled water, and ethanol for about 5 minutes respectively, and drying it with a nitrogen gun.

[0065] In some preferred embodiments of the present invention, the film cleaning process includes cleaning the flexible film with acetone, ethanol, and water in sequence.

[0066] In some more preferred embodiments of the present invention, the film cleaning process includes washing the flexible film with acetone, ethanol, and water in sequence.

[0067] In some embodiments of the present invention, the hot embossing device is a tablet press.

[0068] In some preferred embodiments of the present invention, the "sandwich" structure is placed in a tablet press, the temperature is first raised to T1, and after the temperature stabilizes, pressure is applied and maintained for time t. Then, the tablet is cooled to T2, unloaded, the "sandwich" structure is taken out, and the flexible film is peeled off to obtain a flexible film with a nanochannel array on the surface.

[0069] The second aspect of the present invention provides a flexible film with a channel array prepared by the above preparation method.

[0070] According to an embodiment of the present invention, a method for preparing a flexible film with a channel array has at least the following beneficial effects: the present invention has significant advantages in terms of low cost of equipment and equipment required for preparing a flexible film with a nanochannel array on its surface, simple operation process, intact replicated channels, scalable replication area, and high speed, and can be mass-produced while ensuring pattern accuracy. The prepared flexible film channel array is clear, complete, and has nanometer-level accuracy. These flexible films with channel arrays on their surfaces can be used as substrates to directly grow guided nanowire arrays, thereby providing an ideal flexible substrate for directly growing various organic molecular nanowire in-plane arrays on polymer flexible films and on this basis for batch construction of various micro-nano optoelectronic devices, and also creating a prerequisite for manufacturing flexible optoelectronic devices based on nanowire arrays.

[0071] The third aspect of the present invention proposes the application of the flexible film with the channel array in the field of nanowire arrays and optoelectronic devices.

[0072] In some preferred embodiments of the present invention, the application of the above-mentioned flexible film with a channel array in micro-nano optoelectronic devices is proposed.

[0073] In some preferred embodiments of the present invention, application of the flexible film with the channel array in a flexible optoelectronic device is proposed.

[0074] In some embodiments of the present invention, applications of the flexible film with a channel array in diodes, organic light-emitting diodes, triodes, field-effect transistors, photodetectors, and flexible nanogenerators are proposed.

[0075] In some preferred embodiments of the present invention, application of the flexible film with the channel array in an organic light emitting diode is proposed.

[0076] According to a fourth aspect of the present invention, a photovoltaic device is provided, comprising the flexible film with the channel array.

[0077] In a fifth aspect of the present invention, a method for preparing a photoelectric device is proposed, which is characterized in that it includes the following steps: processing a flexible film: constructing a channel array on the surface of the flexible film by the above method. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0079] Figure 1 This is a flow chart for preparing a flexible film having a nanochannel array on its surface according to an embodiment of the present invention;

[0080] Figure 2This is a physical picture of the tablet press used in the embodiments of the present invention;

[0081] Figure 3 This is a scanning electron microscope microstructure image of a sapphire single crystal wafer after high-temperature annealing;

[0082] Figure 4 (a) AFM microstructure of the horizontal channel of a sapphire single crystal wafer after annealing, with a scale of 200 nm. Figure 4 (b) its channel depth distribution;

[0083] Figure 5 This is a scanning electron microscope microstructure image of the surface of the PI flexible film after hot embossing in Example 1 of the present invention;

[0084] Figure 6 (a) and 6(b) are digital photos of PI film before and after hot embossing, respectively;

[0085] Figure 7 (a) AFM microstructure of the horizontal channel of the PI flexible film after hot embossing in Example 1 of the present invention, with a scale length of 200 nm; Figure 7 (b) its channel depth distribution;

[0086] Figure 8 This is a scanning electron microscope microstructure image of the surface of the PDMS flexible film after hot embossing in Example 2 of the present invention;

[0087] Figure 9 (a) AFM microstructure of the horizontal channel of the PDMS flexible film after hot embossing in Example 2 of the present invention, with a scale length of 200 nm; Figure 9 (b) its channel depth distribution;

[0088] Figure 10 This is a scanning electron microscope microstructure image of the surface of the PEN flexible film after hot embossing in Example 3 of the present invention;

[0089] Figure 11 (a) AFM microstructure of the horizontal channel of the PEN flexible film after hot embossing in Example 3 of the present invention, with a scale length of 200 nm. Figure 11 (b) shows the channel depth distribution. DETAILED DESCRIPTION

[0090] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0091] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0092] In the description of the present invention, "several" means more than one, "plurality" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of "one" or "two" is solely for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0093] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0094] In the description of the present invention, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the exemplary expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0095] Details of the raw materials used in the embodiments of the present invention are as follows:

[0096] PI film: Manufacturer: Taiwan Damai Technology Co., Ltd.; Model: YL-6052CPI / 0.05T; In addition, PI film can also be purchased from Mitsubishi, Japan, thickness: 0.050 mm;

[0097] PDMS film: manufacturer, Gel pak; model, DC184;

[0098] PEN film: manufacturer, Teijin Limited of Japan; model, Teonex (Q51);

[0099] Ultrasonic cleaning machine: manufacturer, Shanghai Bilan Instrument Manufacturing Co., Ltd.; model, BILON6-180;

[0100] Tablet press: manufacturer, Tianjin Jingtuo Instrument Technology Co., Ltd.; model, PCH-600C.

[0101] Example 1

[0102] A method for constructing a channel array on a flexible film surface comprises the following steps:

[0103] (I) Using an M-face sapphire single crystal wafer as the raw material, place it in acetone and clean it in an ultrasonic cleaner for 10 minutes to remove the surface oil. Remove the cleaned sapphire wafer from the acetone and blow dry the surface with dry nitrogen to remove the residual organic solvent. Then place it in a high-temperature box furnace and heat it to 1600°C at a rate of 10°C / min, keep the temperature constant for 10 hours, then cool it down to room temperature of about 25°C and take it out for use. The surface of the wafer after treatment has a The horizontal channel array in the direction was then ultrasonically cleaned with ethanol, acetone, ethanol, distilled water, and ethanol for 10 min each, and dried with a nitrogen gun.

[0104] (II) The transparent PI film was also ultrasonically cleaned with ethanol, acetone, ethanol, distilled water, and ethanol for 5 min each, dried with a nitrogen gun, and placed between two annealed sapphire wafers to obtain a "sandwich" structure.

[0105] (III) Place the "sandwich" structure on the lower heating table of the tablet press, rotate the upper heating table to fit it with the lower heating table, loosen the oil filling screw, set the heating temperature of both heating tables to 230°C, and after the temperature stabilizes, tighten the pressure valve, shake the pressure rod, pressurize to 200 MPa, maintain for 2 hours, cool to 180°C and unload, take out the "sandwich" structure from the tablet press, place it in ice water at about 0°C and quickly cool it for about 3 seconds, peel off the transparent PI film, and finally prepare a nanoscale channel array on the surface of the PI film: the angle between adjacent channel components is 100-140°, the spacing between adjacent channels is 50-150 nm, and the channel depth is 10-30 nm.

[0106] Example 2

[0107] A method for constructing a channel array on a flexible film surface comprises the following steps:

[0108] (I) Using an M-face sapphire single crystal wafer as the raw material, place it in acetone and clean it in an ultrasonic cleaner for 10 minutes to remove the surface oil. Remove the cleaned sapphire wafer from the acetone and blow dry the surface with dry nitrogen to remove the residual organic solvent. Then place it in a high-temperature box furnace and heat it to 1600°C at a rate of 10°C / min, keep the temperature constant for 10 hours, then cool it down to room temperature of about 25°C and take it out for use. The surface of the wafer after treatment has a The horizontal channel array in the direction was then ultrasonically cleaned with ethanol, acetone, ethanol, distilled water, and ethanol for 10 min each, and dried with a nitrogen gun.

[0109] (II) Rinse the PDMS film three times with washing bottles containing acetone, ethanol, and distilled water respectively (the PDMS film is very soft and has a certain stickiness on the surface, so it is not suitable for ultrasonic cleaning). After being gently blown dry with a nitrogen gun, place it between two annealed sapphire wafers to obtain a "sandwich" structure.

[0110] (III) Place the "sandwich" structure on the lower heating table of the tablet press, rotate the upper heating table to fit it with the lower heating table, loosen the oil filling screw, set the heating temperature of both heating tables to 50°C, and after the temperature stabilizes, tighten the pressure valve, shake the pressure rod, and pressurize to 50 MPa. After maintaining for 1 hour, unload, take out the "sandwich" structure, place it in ice water at about 0°C to cool for about 3 seconds, peel off the PDMS film, and finally prepare a nanoscale channel array on the surface of the PDMS film: the angle between adjacent channel components is 100-140°, the spacing between adjacent channels is 50-150 nm, and the channel depth is 10-30 nm.

[0111] Example 3

[0112] A method for constructing a channel array on a flexible film surface comprises the following steps:

[0113] (I) Using an M-face sapphire single crystal wafer as the raw material, place it in acetone and clean it in an ultrasonic cleaner for 10 minutes to remove the surface oil. Remove the cleaned sapphire wafer from the acetone and blow dry the surface with dry nitrogen to remove the residual organic solvent. Then place it in a high-temperature box furnace and heat it to 1600°C at a rate of 10°C / min, keep the temperature constant for 10 hours, then cool it down to room temperature of about 25°C and take it out for use. The surface of the wafer after treatment has a The horizontal channel array in the direction was then ultrasonically cleaned with ethanol, acetone, ethanol, distilled water, and ethanol for 10 min each, and dried with a nitrogen gun.

[0114] (II) The PEN film was also ultrasonically cleaned with ethanol, acetone, ethanol, distilled water, and ethanol for 5 min each, dried with a nitrogen gun, and placed between two annealed sapphire wafers to obtain a "sandwich" structure.

[0115] (III) Place the "sandwich" structure on the lower heating table of the tablet press, rotate the upper heating table to fit it with the lower heating table, loosen the oil filling screw, set the heating temperature of both heating tables to 100 °C, and after the temperature stabilizes, tighten the pressure valve, shake the pressure rod, pressurize to 200 MPa, maintain for 3 hours, cool to 80 °C and unload, take out the "sandwich" structure, place it in ice water at about 0 °C to cool for about 3 seconds, peel off the PEN film, and finally prepare a nanoscale channel array on the surface of the PEN film: the angle between adjacent channel components is 100-140°, the spacing between adjacent channels is 50-150 nm, and the channel depth is 10-30 nm.

[0116] Test example

[0117] This test example tested the sapphire single crystal wafers annealed at high temperature and the flexible film with nano-channel arrays on the surface prepared in Examples 1-3, wherein:

[0118] Scanning electron microscope was used to test the microstructure of sapphire single crystal wafer and flexible film. The test results are as follows: Figure 3 、 5 , 8, 10;

[0119] Atomic force microscopy was used to test the microstructure of the horizontal channels of sapphire single crystal wafers and flexible films, as well as their channel depth distribution. The test results are as follows: Figure 4 As shown in (a), 4(b), 7(a), 7(b), 9(a), 9(b), 11(a), 11(b);

[0120] In addition, digital photos of the PI film before and after hot stamping in Example 1 were taken using a camera, and the results are as follows: Figure 6 (a) and 6(b).

[0121] The present invention adopts annealed M-face sapphire (i.e. α-Al2O3, crystal plane orientation ) single crystal wafer as a template, its surface has A novel nanoscale channel array with V-shaped microstructures (with an angle of 100-140° between adjacent channel planes, a spacing of 50-150 nm between adjacent channels, and a channel depth of 10-30 nm) can be rapidly and completely replicated in batches on various polymer flexible films using a simple mechanical imprinting device at an appropriate temperature. The flexible films are easily peeled from the template, are less susceptible to damage or tearing, and are less susceptible to the introduction of impurities into the flexible films. The replicated channels remain intact, the replication area is scalable, and the replication speed is fast. The process is simple and inexpensive, ensuring pattern accuracy while enabling large-scale production (large-scale replication of nanoscale channels can be achieved simply by increasing the dimensions of the template and the flexible film). The flexible films prepared by this invention can be directly grown on various in-plane arrays of organic molecular nanowires and used to construct a variety of micro-nano optoelectronic devices in batches, providing an ideal flexible substrate. Compared to methods that use micromachining methods to prepare microchannel array templates and then transfer the microchannels to flexible films, this invention can improve the precision of channel arrays on flexible film surfaces to the nanometer level.

[0122] The present invention can replicate the channel array on the template onto various polymer flexible substrates under appropriate temperature and pressure. Different channel patterns can also be quickly replicated on flexible substrates simply by replacing different templates (for example, templates with different micro-nano channel patterns on the surface prepared using techniques such as photolithography or electron beam direct writing). However, the cost of preparing nanoscale channel templates using techniques such as electron beam direct writing is too high. In the embodiments of the present invention, a sapphire template with a "V"-shaped nanoscale channel array on the surface can be obtained by simply annealing the M-plane sapphire at high temperature. Compared with nanoscale channel templates prepared by other methods, this has the advantage of low cost.

[0123] The present invention can use a low-cost small tablet press to first heat the flexible film to an appropriate temperature, which is above the glass transition temperature of the flexible film, and keep it constant. At this time, the film is in a highly elastic state. Then, pressure is applied and maintained for an appropriate time to allow the film to fully fill the grooves of the template. After cooling to below the glass transition temperature of the flexible film, it is unloaded, and a nanoscale channel array can be prepared on the flexible film.

[0124] The versatility of this invention lies in the following aspects: First, by selecting appropriate parameters (hot embossing temperature and pressure), nanoscale channel arrays can be rapidly replicated on various flexible polymer substrates. Second, using the same template, the nanochannels produced on various flexible polymer substrates are virtually identical; the channel shape and size are completely dependent on the template used. Therefore, in principle, different channels can be obtained on a flexible substrate simply by changing the template. The universality of this invention is also demonstrated in the examples of this invention, using surface SEM images of various flexible substrates after hot embossing. Using annealed sapphire single crystal wafers as templates, the nanochannels replicated on various flexible polymer substrates are virtually identical.

[0125] It should be noted that the terms “about” or “approximately” used in this document refer to numerical values ​​with an error of 2%.

[0126] While the embodiments of the present invention have been described in detail above with reference to the accompanying drawings, the present invention is not limited to the embodiments described above. Various modifications may be made within the scope of knowledge possessed by a person skilled in the art without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof may be combined with one another unless there is a conflict.

Claims

1. A method for constructing a channel array on a flexible film surface, characterized in that: The method comprises the following steps: taking a template with a channel array, placing a flexible film to be processed between two templates to obtain a stacked structure, performing a hot embossing process on the stacked structure to copy the channel array on the template to the surface of the flexible film to be processed by hot embossing, thereby constructing a channel array on the surface of the flexible film; then placing the stacked structure in ice water to cool it, and peeling off the flexible film; The template is a heat-resistant imprinting template, specifically an annealed M-plane sapphire; The hot embossing process includes heating the flexible film to be processed until it is in a highly elastic state, applying pressure and maintaining it for a period of time, and cooling. Specifically, the process includes heating the flexible film to a temperature T1, applying pressure to a pressure P and maintaining it for a period of time t, cooling the flexible film to a temperature T2, and then unloading and removing the laminated structure. In this case, T1>0°C, T2>0°C, the glass transition temperature of the flexible film to be processed<T1<the melting point of the flexible film, and T2<the glass transition temperature of the flexible film.

2. The method for constructing a channel array on a flexible film surface according to claim 1, characterized in that: Heat up to temperature T1, and start pressurizing after the temperature stabilizes.

3. The method for constructing a channel array on a flexible film surface according to claim 1, characterized in that: 50℃≤T1≤230℃, 50℃≤T2≤180℃.

4. The method for constructing a channel array on a flexible film surface according to claim 3, characterized in that: Said P=50-300 MPa.

5. The method for constructing a channel array on a flexible film surface according to claim 4, characterized in that: Said t=1-5 h.

6. The method for constructing a channel array on a flexible film surface according to claim 5, characterized in that: Said t=2-5 h.

7. The method for constructing a channel array on a flexible film surface according to claim 1, characterized in that: The surface of the M-plane sapphire has A "V"-shaped nanoscale channel array in the direction, wherein the angle between adjacent channel components of the channel array is 100-140°, the spacing between adjacent channels is 50-150 nm, and the channel depth is 10-30 nm.

8. The method for constructing a channel array on a flexible film surface according to claim 1, characterized in that: The M-plane sapphire is an M-plane sapphire single crystal wafer.

9. The method for constructing a channel array on a flexible film surface according to claim 1, characterized in that: The annealing process of the M-plane sapphire includes: heating the temperature to 1550-1650°C at a rate of 8-12°C / min, maintaining the temperature for 9-11 hours, and cooling to room temperature.

10. The method for constructing a channel array on a flexible film surface according to claim 9, characterized in that: The annealing process includes: heating the temperature to about 1600° C. at a rate of about 10° C. / min, maintaining the temperature for about 10 hours, and cooling to room temperature.

11. The method for constructing a channel array on a flexible film surface according to claim 1, characterized in that: The flexible film comprises a high molecular flexible material.

12. The method for constructing a channel array on a flexible film surface according to claim 11, characterized in that: The polymer flexible material includes at least one of PI, PET or PEN.

13. The method for constructing a channel array on a flexible film surface according to claim 12, characterized in that: The flexible film is a PI film with a temperature range of 220°C≤T1≤230°C and a pressure resistance of 150 MPa≤P≤200 MPa.

14. The method for constructing a channel array on a flexible film surface according to claim 1, characterized in that: Before hot stamping, the flexible film is cleaned before being sandwiched between the templates.

15. The method for constructing a channel array on a flexible film surface according to claim 14, characterized in that: The film cleaning process includes sequentially cleaning the flexible film with acetone, ethanol and water.

16. The method for constructing a channel array on a flexible film surface according to claim 14, characterized in that: The film cleaning process includes sequentially cleaning the flexible film with ethanol, acetone, ethanol, water, and ethanol.

17. The method for constructing a channel array on a flexible film surface according to claim 14, characterized in that: The film cleaning process includes ultrasonically cleaning the flexible film with ethanol, acetone, ethanol, water and ethanol in sequence for 5-10 minutes.

18. The method for constructing a channel array on a flexible film surface according to claim 14, characterized in that: The film cleaning process includes ultrasonically cleaning the flexible film with ethanol, acetone, ethanol, water, and ethanol in sequence for about 5 minutes.

19. A flexible film with a channel array, characterized in that: The channel array is constructed by the method according to any one of claims 1 to 18.

20. Use of the flexible film with a channel array as claimed in claim 19 in a photovoltaic device.

21. A photoelectric device, characterized in that: The flexible film with a channel array as claimed in claim 19 is included.

22. A method for preparing a photoelectric device, characterized in that: The method comprises the following steps: processing the flexible film: constructing a channel array on the surface of the flexible film by the method according to any one of claims 1 to 18.

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