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CN-117558488-B - Flexible transparent conductive film with metal grid, and preparation method and application thereof

CN117558488BCN 117558488 BCN117558488 BCN 117558488BCN-117558488-B

Abstract

The invention discloses a flexible transparent conductive film with metal grid, a preparation method and application thereof, comprising a flexible substrate and a sputtered metal mesh forming various desired patterns on the flexible substrate. The invention adopts a magnetron sputtering method to accurately control the thickness of the metal grid layer by controlling the deposition time, thereby preparing the flexible transparent conductive film with good quality, high transmittance, high conductivity and strong bending resistance, being used as a flexible transparent electrode material with excellent property, meeting the requirements of a flexible display screen or flexible electrons, and being simple, safe and nontoxic in preparation process and convenient for preparing large-area metal grids.

Inventors

  • LV JIAN
  • Xiao Xufen
  • BU YU
  • LIU PENGFEI

Assignees

  • 香港城市大学深圳福田研究院

Dates

Publication Date
20260512
Application Date
20231008

Claims (15)

  1. 1. A flexible transparent conductive film of metal grid, which is characterized in that the film comprises a flexible substrate and a sputtered metal grid, wherein the metal grid forms various required patterns on the flexible substrate; The flexible substrate is selected from a soft PET substrate, a CPI substrate or flexible ultrathin glass; The metal grid is a metal Ag grid; the preparation method of the metal grid flexible transparent conductive film comprises the following steps: S1, preparing a polymer template, and cutting a required hollowed-out stripe pattern in the center of the polymer template; s2, preparing a flexible substrate, attaching the flexible substrate to a base plate to form a flexible substrate/base plate combination, and fixing the polymer template prepared in the step S1 on the flexible substrate to form a template/substrate/base plate combination; S3, putting the template/substrate combination into a magnetron sputtering coating device, introducing rare gas under vacuum condition, adjusting power, sputtering a metal target material on a flexible substrate by using a magnetron sputtering method for deposition, and removing the template to obtain the metal grid flexible transparent conductive film; In the step S3, the template faces the Ag target, the vacuum is pumped to 10 -5 ~10 -9 torr, the magnetron sputtering gas Ar bombards the target, the power is 300-500 w, the deposition time is 90-600S, and the partial pressure of Ar is controlled to be 60% -70%; the thickness of the metal grid is 150 nm-600 nm; the line width of the metal grid is 1-30 mu m; the sheet resistance of the metal grid flexible transparent conductive film is 4-10 omega sq -1 .
  2. 2. The metal grid flexible transparent conductive film according to claim 1, wherein the metal grid forms a metal square grid, a metal triangle grid, a metal brick wall grid, a metal honeycomb grid, a metal circular grid pattern on the flexible substrate.
  3. 3. The metal grid flexible transparent conductive film according to claim 1, wherein the metal grid has a size area ranging from 2cm x 2cm to 20cm x 20cm.
  4. 4. A metal grid flexible transparent conductive film according to any one of claims 1-3, wherein the metal grid has a light transmittance of 90% or more at 550 nm.
  5. 5. The metal grid flexible transparent conductive film according to claim 4, wherein the light transmittance of the metal grid at 550nm is 92% or more.
  6. 6. The metal grid flexible transparent conductive film according to claim 5, wherein the light transmittance of the metal grid at 550nm is 93.5% or more.
  7. 7. A metal grid flexible transparent conductive film according to any one of claims 1-3, wherein the metal grid flexible transparent conductive film has an overall transmittance of 82% or more at 550 nm.
  8. 8. The flexible transparent conductive metal mesh film according to claim 1, wherein the step S1 is to cut a desired hollowed-out stripe pattern in the center of the polymer template by using a laser.
  9. 9. The metal grid flexible transparent conductive film according to claim 8, wherein different polymer template patterns are obtained by adjusting cutting parameters of laser, the cutting parameters comprise cutting energy, cutting interval and cutting length, the cutting energy is 8-20W, the cutting interval is 100-500 μm, and the cutting length is 2-20 cm.
  10. 10. The flexible transparent conductive metal mesh film according to claim 1, wherein the step S2 further comprises the steps of cleaning the flexible substrate with acetone and ethanol solution and deionized water in a volume ratio of 1:1 in sequence, drying with nitrogen, and fixing the polymer template on the flexible substrate with a high-temperature adhesive tape.
  11. 11. The metal grid flexible transparent conductive film according to claim 1, wherein the deposition time of magnetron sputtering is 90 s-300 s.
  12. 12. The flexible transparent conductive metal mesh film according to claim 1, wherein the polymer template is a polyimide sheet, and the overall size of the polymer template is 4 x 4-24 x 24 cm, and the thickness is 30-90 μm.
  13. 13. The metal mesh flexible transparent conductive film according to claim 1, wherein the metal target is at least one of Ag target, cu target, al target, au target.
  14. 14. The flexible transparent conductive metal mesh film according to claim 1, wherein the pattern of the polymer template is a parallel hollowed-out stripe pattern, and the conductive film with square, triangular or crossed metal mesh patterns is obtained in step S3 by coating 2, 3 or 4 times respectively.
  15. 15. Use of the metal grid flexible transparent conductive film of any one of claims 1 to 14 in a flexible display screen or a flexible electronic device.

Description

Flexible transparent conductive film with metal grid, and preparation method and application thereof Technical Field The invention belongs to the technical field of metal films, and particularly relates to a metal grid flexible transparent conductive film, and a preparation method and application thereof. Background Transparent Electrodes (TEs) play a critical role in many modern devices, including solar cells, light emitting diodes, touch screens, wearable electronics, transparent heaters, and the like. The transparent electrode field has long been dominated by Transparent Conductive Oxides (TCOs). Early In the 50 s of the 20 th century, a wide bandgap semiconductor material with high optical transparency, such as SnO 2 and In 2O3, was reported, which can be enhanced In conductivity by impurity doping. Through extensive research over 60 years, indium Tin Oxide (ITO) thin films have been developed as a representative transparent electrode material having excellent optical and electronic properties, and have been widely commercialized. However, in recent years, there has been an increasing demand for flexibility, stretchability and foldability of flexible electronic devices, and ITO is not only limited in production by a serious shortage of indium resources, but also is itself inferior in mechanical flexibility and is liable to develop cracks upon strain or bending. Although the ITO/PET substrate can be applied to flexible optoelectronic devices in the current market, due to the brittleness of the ITO, the bending strain tolerance and the cyclic fatigue resistance of the ITO on the flexible substrate are insufficient, so that the flexible ITO/PET substrate is difficult to be practically applied to stretchable, foldable or bendable optoelectronic devices. Therefore, the search for new materials with higher and additional properties is one of the most intense studies currently. New materials need to have better flexibility and stability, richer and usable raw materials and lower processing costs. Based on this goal, some emerging transparent conductive materials emerge as alternatives to conventional ITO, mainly including three types of materials, i) carbon nanomaterials such as Carbon Nanotubes (CNTs) or graphene, ii) conductive polymers (e.g., PEDOT: PSS), iii) metallic nanomaterials such as metallic nanofilms, metallic nanowire networks, metallic grids, and the like. These materials have been widely studied and proved to have a high potential in overcoming the disadvantages of ITO. Among all the emerging materials replacing ITO, metallic nanomaterials exhibit higher optical and electrical properties than carbon nanomaterials (e.g., graphene or carbon nanotubes, etc.). In addition, the metal nanomaterial is receiving attention because of its remarkable additional advantages such as good mechanical properties such as flexibility and stretchability, low cost, ease of manufacture, flexibility, and wide applicability. Among the metallic grid-like nanomaterials, the methods currently in common use for preparing metallic grids are photolithography-based techniques such as optical lithography and nanoimprint lithography. The photoetching technology can accurately control the grid pattern, but the line width of the photoetching technology is larger, so that the Morey interference problem is easily caused, and the application of the photoetching technology to products such as high-resolution smart phones and tablet computers is limited. Another nanoimprint lithography technique, although reducing line width, requires the simultaneous use of techniques such as electron beam lithography or focused ion beam lithography, or the use of electron beam evaporation techniques, increasing fabrication time and cost. Other methods of preparing metal grids such as templated electrodeposition and imprint transfer processes. By embedding the metal mesh in the high molecular polymer, a high-performance metal mesh transparent electrode excellent in surface smoothness can be obtained. However, such processes typically involve complex multiple transfer and stripping steps, which can lead to reduced cost effectiveness at large scale manufacturing and can present process repeatability and uniformity problems. As the availability of ITO in the transparent electrode market decreases, the technology of preparing metal grids and other ITO substitutes is expected to continue to grow. The metal mesh may exhibit better optical and electrical properties than the ITO thin film due to the high adjustability of its microstructure, and may be independently optimized for optical transmittance and electrical conductivity compared to other metal materials (e.g., ultra-thin metal thin films), enabling an optimal balance between optical and electrical properties. However, metal grids still face challenges of 1) the relative trade-off between transparency and conductivity still needs to be addressed in a simpler manner during the manufacturing process, an