WO2021114910A1 - Stripping transfer method for large-area metal oxide nanoarray - Google Patents

Abstract

A stripping transfer method for a large-area metal oxide nanoarray, comprising: (1) selecting a substrate material having a lattice constant mismatch rate greater than 5% and a thermal expansion coefficient difference greater than 5*10 ^-6K with respect to those of the metal oxide; (2) pre-preparing a metal oxide seed layer film on the surface of the substrate material, wherein the annealing temperature is controlled at 200-500°C; (3) immersing into the hydrothermal precursor solution the substrate material having the metal oxide seed layer film prepared on the surface thereof to perform hydrothermal reaction to grow a layer of metal oxide nanoarray on the surface; (4) performing heat treatment on the prepared metal oxide nanoarray at 200-500°C to achieve separation from the substrate material; and (5) stripping the metal oxide nanoarray into an organic binder or sol, selecting a target substrate, taking out the separated metal oxide nanoarray and attaching same to the surface of the target substrate, and then, performing heat treatment at 200-500°C in an air atmosphere to remove residual organic matters, so as to achieve the transfer of the metal oxide nanoarray.

Description

Stripping transfer method of large-area metal oxide nano-array

The present invention claims the priority of the prior application of the application number 201911288794.5 filed on December 12, 2019 under the title of "A Method for Exfoliating and Transferring Large Area Metal Oxide Nanoarrays", and the content of the foregoing prior application is introduced by way of introduction. Incorporated into this text.

Technical field

The invention relates to a stripping transfer method of a large-area metal oxide nano-array, belonging to the field of manufacturing nano-photoelectric devices.

Background technique

Nanostructures such as metal oxide nanorods and nanosheets are arranged vertically, uniformly, and orderly on the base material to form metal oxide nanoarrays. They exhibit excellent performance in various fields such as solar cells, gas sensors, and photocatalysis. . The preparation process of metal oxide nanoarrays on various substrate materials has been quite mature, but the lift-off transfer process of large-area metal oxide nanoarrays still needs to be developed and improved. The simple and rapid stripping transfer of large-area metal oxide nanoarrays is beneficial to simplify the manufacturing process of optoelectronic devices and improve the integration and stability of the devices.

Shujie Wang et al. (RSC Advances, Vol. 6 (2016), pp. 64332～64337) reported the transfer of ZnO nanorod arrays using nanoimprint assisted vertical transfer. It fills the polymethyl methacrylate (PMMA) organic matter into the gaps of the ZnO nanorod array by increasing the temperature, while the top of the ZnO nanorod array is embedded in the silver paste electrode, thereby making the ZnO nanorod array, PMMA and silver paste Form a whole. Then, a nanoimprint platform is used to apply stress to the ZnO nanorods to realize the separation of the ZnO nanorod array from the growth substrate, so as to peel off the ZnO nanorod array and transfer it to the target substrate. Although this method can realize the transfer of ZnO nanorod arrays to various substrates, the transfer process is relatively complicated, requires special equipment, and may cause damage to the ZnO nanorods.

Summary of the invention

In view of the problems and deficiencies in the prior art, the present invention aims to provide a loose operating environment that can make the metal oxide nanoarray (such as the above-mentioned ZnO nanorod array) spontaneously separate from the base material, thereby achieving simple and rapid peeling And the method of transferring metal oxide nano-arrays. The method of the present invention can realize that the metal oxide nano array prepared by the hydrothermal method is separated from the base material in a large area after annealing, so that the large area metal oxide nano array is simply and quickly transferred to the target substrate. No organic resin encapsulation was used in the transfer process, and no other equipment was used. Therefore, the exfoliation transfer method of the present invention is simpler than any reported method, and can transfer the metal oxide nanoarray to any target substrate, even a curved substrate, so that it is more suitable for large-scale and low-cost manufacturing of nanodevices. According to the method of the present invention, the area of the metal oxide nanoarray that can be peeled and transferred is as high as 1 cm ² .

Specifically, the present invention provides a method for exfoliating and transferring a large-area metal oxide nanoarray, the method including the following steps:

(1) Select a base material with a lattice constant mismatch rate greater than 5% and a thermal expansion coefficient difference greater than 5×10 ^{-6 K with the metal oxide;}

(2) Pre-preparing a metal oxide seed layer film on the surface of the base material, and controlling the annealing temperature at 200-500°C in the process;

(3) Immerse the base material with a metal oxide seed layer film prefabricated on the surface into a hydrothermal precursor solution to conduct a hydrothermal reaction, thereby growing a layer of metal oxide nanoarray on the surface of the base material;

(4) Heat treatment of the metal oxide nanoarray prepared by hydrothermal treatment at 200-500°C to realize the separation of the metal oxide nanoarray from the base material; and

(5) The metal oxide nanoarray is peeled off into an organic binder or sol, and a target substrate is selected to pick up the separated metal oxide nanoarray and attach it to the surface of the target substrate. Heat treatment is performed at a temperature of ~500° C. in an air atmosphere to remove residual organic matter, so as to realize the transfer of the metal oxide nano-array.

Among them, preferably, metal oxide nanoarrays that can be stripped and transferred in a large area according to the method of the present invention include ZnO nanoarrays, CuO nanoarrays, NiO nanoarrays, Co ₃ O ₄ nanoarrays, and the like. Wherein the hydrothermal precursor solution is prepared by mixing a nitrate solution of the corresponding metal of the metal oxide with an amine solution; wherein the amine solution includes but is not limited to cyclohexamethylenetetramine (HMTA) solution and Urea solution; wherein the substrate material includes but not limited to glass substrate and Si substrate, preferably FTO glass substrate or Si substrate; wherein the organic binder includes but not limited to Triton and terpineol, the sol is The metal oxide corresponds to a metal acetate sol.

The feature of the present invention is that the metal oxide nanoarray prepared by the hydrothermal method can be spontaneously separated from the substrate material in a large area, and can be easily peeled off into the organic binder or sol after heat treatment, and the target substrate is used for fishing to achieve a large area. Metal oxide nano-arrays are easily and quickly transferred.

Compared with the prior art, the advantage of the patent of the present invention is that the present invention can realize the spontaneous separation of the large-area metal oxide nanoarray from the substrate material without the aid of organic resin and special equipment, so that it can be applied to any target substrate. Even transfer on curved substrates. This method is simpler than previously reported methods, making it more suitable for the preparation of large-scale, low-cost nanodevices.

Description of the drawings

FIG. 1 shows the XRD pattern of the ZnO seed layer prepared on the surface of the common glass substrate of Example 1.

2 shows the XRD pattern of the ZnO nanorod array grown on the surface of the common glass substrate of Example 1.

Fig. 3 shows a photograph of the ZnO nanorod array of Example 1 being peeled off from a common glass substrate.

FIG. 4 shows the FESEM image of the ZnO nanorod array transferred to the surface of the curved ceramic tube of Example 1. FIG.

5 shows the XRD pattern of the CuO nanoarray grown on the surface of the FTO glass substrate of Example 2.

6 shows the FESEM image of the CuO nano-array grown on the surface of the FTO glass substrate of Example 2.

Detailed ways

The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. It is obvious that the described embodiments are merely examples of the implementation of the present invention, and the scope of the present invention is not limited to the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work will fall within the protection scope of the present invention.

Example 1 Exfoliation and transfer of ZnO nanorod array

A layer of ZnO film was prepared by spin coating and annealing on the surface of a common glass substrate with an area of 4 cm ^{2 and annealed 5 times (Figure 1 shows the XRD pattern of the ZnO film).} Prepare 0.2 mol/L Zn(NO ₃ ) ₂ and 80 ml of HMTA aqueous solution, and mix these two solutions to obtain a hydrothermal precursor solution. The ordinary glass substrate spin-coated with the ZnO film was immersed in the hydrothermal precursor solution and kept at 90°C for 4 hours. After the hydrothermal reaction solution is naturally cooled to room temperature, the ordinary glass substrate is taken out, washed with deionized water, and dried.

By visually observing the ordinary glass substrate after drying, it was found that part of the ZnO nanorod array was separated from the ordinary glass substrate. The separated part appears white, and the unseparated part appears colorless. The XRD pattern shows that the ZnO nanorod array grows preferentially along the [001] crystal direction, as shown in Figure 2.

The ordinary glass substrate on which the ZnO nanorod array was grown was annealed at 400°C for 30 minutes. After the temperature dropped to room temperature, it was found that the area of the ZnO nanorod array separated from the ordinary glass substrate increased significantly, up to 1cm ² (Figure 3) Shown). The separated ZnO nanorod array is peeled from the glass substrate into the Triton adhesive. The ZnO nanorod array can be bent freely in the Triton adhesive and exhibits good flexibility. Then, a curved ceramic tube is used to retrieve the ZnO nanorod array, and the ZnO nanorod array is spontaneously attached to the curved ceramic tube. Finally, the curved ceramic tube is heat-treated at 400°C to realize the transfer of the large-area ZnO nanorod array to the curved ceramic tube. As shown in Figure 4, the FESEM image showed that the structure of the ZnO nanorod array transferred to the curved ceramic tube was not damaged.

Example 2 Exfoliation and Transfer of CuO Nano Array

A layer of CuO film was prepared by spin coating-annealing method on the surface ^{of FTO glass substrate with an area of 4 cm 2} by spin coating and annealing 5 times. Prepare 0.2 mol/L Cu(NO ₃ ) ₂ and 80 ml of HMTA aqueous solution, and mix these two solutions to obtain a hydrothermal precursor solution. The FTO glass substrate spin-coated with CuO film was immersed in the hydrothermal precursor solution and kept at 90°C for 4 hours. After the hydrothermal reaction solution is naturally cooled to room temperature, the FTO glass substrate is taken out, washed with deionized water, and dried.

By visually observing the dried FTO glass substrate, it was found that part of the CuO nanoarray was separated from the substrate. Figures 5 and 6 are the XRD patterns and FESEM images of the CuO nanoarray, respectively.

The FTO glass substrate on which the CuO nano-array is grown is annealed at 400° C. for 30 minutes. After the temperature drops to room temperature, it is found that the area of the CuO nano-array separated from the FTO glass substrate is significantly increased, up to 1 cm ² . The separated CuO nanoarray is peeled from the FTO glass substrate into the terpineol binder, and the CuO nanoarray can be bent freely in the terpineol binder, showing good flexibility. Then, a curved ceramic tube is used to pick up the CuO nano-array, and the CuO nano-array is spontaneously attached to the curved ceramic tube. Finally, the curved ceramic tube is heat-treated at 400°C to realize the transfer of the large-area CuO nano-array to the curved ceramic tube.

Example 3 Exfoliation and transfer of NiO nanoarray

A layer of NiO film was prepared by spin coating-annealing method on the ^{surface of Si substrate with an area of 4 cm 2} by spin coating and annealing 3 times. Prepare 0.15 mol/L Ni(NO ₃ ) ₂ and 90 ml of HMTA aqueous solution, and mix these two solutions to obtain a hydrothermal precursor solution. The Si substrate spin-coated with NiO film was immersed in the hydrothermal precursor solution and kept at 90°C for 4 hours. After the hydrothermal reaction solution is naturally cooled to room temperature, the Si substrate is taken out, washed with deionized water, and dried.

By visually observing the dried Si substrate, it was found that part of the NiO nanoarray was separated from the Si substrate. The phase and morphology of the NiO nanoarray can be known through XRD patterns and FESEM images.

The Si substrate on which the NiO nanoarray was grown was annealed at 500°C for 10 minutes. After the temperature dropped to room temperature, it was found that the area of the NiO nanoarray separated from the Si substrate increased significantly, reaching 1cm ² . The separated NiO nano-array is peeled from the Si substrate into the nickel acetate sol. The NiO nano-array can be bent freely in the nickel acetate sol and exhibits good flexibility. Then, the NiO nano-array is picked up by the flexible polytetrafluoroethylene substrate with interdigital electrodes, and the NiO nano-array is spontaneously attached to the flexible polytetrafluoroethylene substrate. Finally, the PTFE flexible substrate is heat-treated at 350°C to realize the transfer of the large-area NiO nano-array to the PTFE flexible substrate. The FESEM image showed that the structure of the NiO nanoarray transferred to the flexible PTFE substrate was not damaged.

Example 4 Stripping and Transfer of Co3O4 Nano Array

The spin coating-annealing method was used to spin-coat and anneal 3 times on the surface of a Si substrate ^{with an area of 4 cm 2} _{to prepare a Co 3} O ₄ film. Prepare 0.15 mol/L Co(NO ₃ ) ₂ and 90 ml of urea aqueous solution, and mix these two solutions to obtain a hydrothermal precursor solution. The Si substrate spin-coated with the Co ₃ O ₄ film was immersed in the hydrothermal precursor solution and kept at 95° C. for 6 hours. After the hydrothermal reaction solution is naturally cooled to room temperature, the Si substrate is taken out, washed with deionized water, and dried.

By visually observing the dried Si substrate, it was found that part of the Co ₃ O ₄ nano-array was separated from the Si substrate. The phase and morphology of the _{Co 3} O ₄ nano-array can be known through XRD patterns and FESEM images.

The Si substrate on which the Co ₃ O ₄ nano-array was grown was annealed at 500° C. for 10 minutes. After the temperature dropped to room temperature, it was found that _{the area of the Co 3} O ₄ nano-array separated from the Si substrate was significantly increased, reaching 1 cm ² . The separated Co ₃ O ₄ nano-array is peeled from the Si substrate into the cobalt acetate sol. The Co 3 O 4 nano-array can be bent freely in the cobalt acetate sol and exhibits good flexibility. Then, a flexible polytetrafluoroethylene substrate with interdigital electrodes is used to harvest the Co ₃ O ₄ nano-array, and the Co ₃ O ₄ nano-array is spontaneously attached to the flexible polytetrafluoroethylene substrate. Finally, the flexible polytetrafluoroethylene substrate is heat-treated at 300°C to realize the transfer of the large-area Co ₃ O ₄ nano-array to the flexible polytetrafluoroethylene substrate. _{The FESEM image showed that the structure of the Co 3} O ₄ nano-array transferred to the flexible polytetrafluoroethylene substrate was not damaged.

The beneficial effect of the present invention is that the present invention can realize the simple and rapid peeling and transfer of metal oxide nano-arrays with ^{an area of 1 cm 2 without the aid of organic resins and special instruments and equipment, and can be transferred to curved substrates and flexible substrates.} on. This method is simpler than previously reported methods, making it more suitable for the preparation of large-scale, low-cost nanodevices, and is conducive to expanding the assembly form of nanodevices.

It is obvious that the above embodiments are only preferred embodiments of the present invention, and the present invention is not limited thereby. Any modification, equivalent replacement and improvement made within the spirit and principle of the present invention shall fall within the protection scope of the present invention. The above are only the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the technical principles of the present invention, several improvements and modifications can be made. These improvements and modifications It should also be regarded as falling within the protection scope of the present invention.

Claims (10)

1. A method for peeling and transferring a metal oxide nanoarray, the method comprising the following steps:

   (1) Select a base material with a lattice constant mismatch rate greater than 5% and a thermal expansion coefficient difference greater than 5×10 ^{-6 K with the metal oxide;}

   (2) Pre-preparing a metal oxide seed layer film on the surface of the base material, and controlling the annealing temperature at 200-500°C in the process;

   (3) Immerse the base material with a metal oxide seed layer film prefabricated on the surface into a hydrothermal precursor solution to conduct a hydrothermal reaction, thereby growing a layer of metal oxide nanoarray on the surface of the base material;

   (4) Heat treatment of the metal oxide nanoarray prepared by hydrothermal treatment at 200-500°C to realize the separation of the metal oxide nanoarray from the base material; and

   (5) The metal oxide nanoarray is peeled off into an organic binder or sol, and a target substrate is selected to pick up the separated metal oxide nanoarray and attach it to the surface of the target substrate. Heat treatment is performed at a temperature of ~500° C. in an air atmosphere to remove residual organic matter, so as to realize the transfer of the metal oxide nano-array.
2. The method according to claim 1, wherein the metal oxide is selected from ZnO, CuO, NiO and Co ₃ O ₄ .
3. The method according to claim 1 or 2, wherein the substrate material includes, but is not limited to, a glass substrate and a Si substrate.
4. The method according to claim 3, wherein the substrate material is an FTO glass substrate.
5. The method according to claim 1 or 2, wherein the hydrothermal precursor solution is prepared by mixing a nitrate solution of the corresponding metal of the metal oxide and an amine solution.
6. The method according to claim 5, wherein the amine solution includes, but is not limited to, a cyclohexamethylenetetramine solution and a urea solution.
7. The method according to claim 1 or 2, wherein the target substrate is a curved substrate.
8. The method according to claim 1 or 2, wherein the organic binder includes, but is not limited to, triton and terpineol.
9. The method according to claim 1 or 2, wherein the sol is an acetate sol of the corresponding metal of the metal oxide.
10. The method according to claim 1 or 2, wherein the transfer area of the metal oxide nanoarray is up to 1 cm ² .

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