Transparent conductive film

Abstract

The present invention discloses a novel and inventive transparent conductive film Differing from conventional metal mesh substrates are mainly constituted by silver nanowires (AgNW), the present invention particularly designs a nano metal wire consisting of a metallic core wire, a transition layer and a protection layer, and further develops a transparent conductive film consisting of a substrate and a metal mesh layer; wherein the metal mesh layer is constituted by the said nano metal wires. It is worth describing that, a variety of experimental data prove that the thermal resistance of this novel transparent conductive film is up to 400 C.; moreover, experimental data also exhibit that the transparent conductive film can filter part of blue light portion out of a white light by 20-30%.

Claims

1. A transparent conductive film, comprising: a transparent substrate; and a metal mesh layer formed on the transparent substrate, wherein the metal mesh layer comprises a plurality of nano metal wires, and each of the plurality of nano metal wires comprising: a metallic core wire, being made of a first manufacturing material selected from the group consisting of silver (Ag), gold (Au), copper (Cu), nickel (Ni), and titanium (Ti); a transition layer, covering the metallic core wire and being made of a metal compound; and a protection layer, covering the transition layer and being made of a first oxide; wherein the metal compound is formed by a metal that is the same as a metal in the metallic core wire, an oxide of the metal that is the same as the metallic core wire, poly(vinylpyrrolidone) (PVP), and the first oxide.

2. The transparent conductive film of claim 1, wherein the transparent substrate is a rigid substrate or a flexible substrate.

3. The transparent conductive film of claim 1, wherein the diameter of the metallic core wire is in a range from 5 nm to 500 nm, and the length of the metallic core wire is ranged between 0.1 m and 1000 m.

4. The transparent conductive film of claim 1, wherein the first oxide is selected from the group consisting of: titanium oxide, zinc oxide, aluminum oxide, niobium oxide, vanadium oxide, nickel oxide, cupric oxide, zirconium oxide, and indium oxide.

5. The transparent conductive film of claim 1, wherein the thickness of the oxide is in a range from 1 nm to 30 nm.

6. The transparent conductive film of claim 1, wherein the protection layer also covers the surface of the transparent substrate.

7. The transparent conductive film of claim 1, wherein the metallic core wires are formed on the transparent substrate through a specific process selected from the group consisting of: spin coating process, rod coating process, drop casting process, and air spraying process.

8. The transparent conductive film of claim 1, wherein the protection layer is formed on the transition layer through atomic layer deposition (ALD) process.

9. The transparent conductive film of claim 1, wherein any two metallic core wires have an intersection nano dot having a dot size in a range from 20 nm to 1000 nm.

10. The transparent conductive film of claim 9, wherein the thickness of the metal compound is in a range from 0.1 nm to 50 nm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention as well as a preferred mode of use and advantages thereof will be best understood by referring to the following detailed description of an illustrative embodiment in conjunction with the accompanying drawings, wherein:

(2) FIG. 1 shows a schematic framework view of a conventional touch panel having metal mesh layer;

(3) FIG. 2 shows a schematic stereo view of a transparent conductive film according to the present invention;

(4) FIG. 3 illustrates a stereo diagram for showing a part of structure of a metal mesh layer;

(5) FIG. 4A, FIG. 4B and FIG. 4C show manufacturing process flow of the transparent conductive film disclosed by the present invention;

(6) FIG. 5 shows electron microscope images of nano metal wires for forming the metal mesh layer;

(7) FIG. 6 shows electron microscope images of the nano metal wires;

(8) FIG. 7 shows a data curve plot of time of thermal process versus resistance ratio;

(9) FIG. 8 shows a data curve plot of time of thermal process versus resistance ratio;

(10) FIG. 9 shows a plot diagram including curves of wavelength versus transmittance and curves of wavelength versus luminous intensity.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(11) To more clearly describe a transparent conductive film according to the present invention, embodiments of the present invention will be described in detail with reference to the attached drawings hereinafter.

(12) FIG. 2 illustrates a schematic stereo view of a transparent conductive film according to the present invention is provided. As FIG. 2 shows, the transparent conductive film 1 of the present invention mainly consists of a transparent substrate 11 and a metal mesh layer 12 formed on the transparent substrate 11, wherein the transparent substrate 11 can be a rigid substrate made of glass or a flexible substrate made of PET.

(13) Continuously referring to FIG. 2, and please simultaneously refer to FIG. 3, where a stereo diagram for showing a part of structure of a metal mesh layer is provided. From FIG. 2 and FIG. 3, it is able to know that the metal mesh layer 12 is constituted by a plurality of nano metal wires 120, wherein each of the nano metal wires 120 consist of a metallic core wire 121, a transition layer 122 and a protection layer 123. The said metallic core wire 121 is made of a first manufacturing material, for example, silver (Ag), gold (Au), copper (Cu), nickel (Ni), or titanium (Ti). Moreover, the metallic core wire 121 has a specific diameter ranged from 5 nm to 500 nm and a specific length ranged between 0.1 m to 1000 m.

(14) On the other hand, the transition layer 122 covering the metallic core wire 121 is a metal compound. It needs to particularly explain that, the said metal compound, depending upon the discrepancy of the manufacturing process conditions, may be formed by following two groups of material composition: (I) a metal made of a second manufacturing material, a second oxide of the metal, a PVP (Poly(vinyl pyrrolidone)), and the first oxide, wherein the second manufacturing material is same as the first manufacturing material of the metallic core wire; and (II) a metal made of a second manufacturing material, oxygen and carbon, wherein the second manufacturing material is same as the first manufacturing material of the metallic core wire.

(15) In the constitution of the nano metal wires 120, the said protection layer 123 covering the transition layer 122 is made of the aforesaid second oxide such as titanium oxide, zinc oxide, aluminum oxide, niobium oxide, vanadium oxide, nickel oxide, cupric oxide, zirconium oxide, or indium oxide.

(16) Experimental Embodiment:

(17) Above descriptions have fully introduced the constitutions and the structure of the transparent conductive film of the present invention. In following paragraphs, experimental embodiment of the novel transparent conductive film using Ag and TiO.sub.2 as the metallic core wire 121 and the protection layer 123 is provided for verifying the practicability of the transparent conductive film 1. FIG. 4A, FIG. 4B and FIG. 4C provide manufacturing process flow of the transparent conductive film disclosed by the present invention. To fabricate this novel transparent conductive film 1, silver nano wires (AgNW) dispersion 2 (or suspension) is firstly coated onto the transparent substrate 11 by using a specific process, for example, spin coating process, rod coating process, drop casting process, or air spraying process; after that, the AgNW coated onto the transparent substrate 10 is subsequently treated with a heat process such as annealing. Therefore, it can observe that the transparent substrate 10 is provided with a metal mesh layer 12 thereon, wherein the metal mesh layer 12 is formed by the metallic core wires 121. Eventually, after forming the protection layer 123 onto the transparent substrate 11 through atomic layer deposition (ALD) process, the transparent substrate 11 and the transition layer 122 are simultaneously covered by the protection layer 123.

(18) Please refer to FIG. 5, which shows electron microscope images of nano metal wires, wherein image (a) and image (b) in FIG. 5 are captured by using the electron microscope under different resolving powers of 500 nm and 50 nm. Moreover, image (b) is obtained by zoom in part of structure of the image (a). From image (b), it can clearly see any two metallic core wires 121 have an intersection nano dot 124, and the said intersection nano dot 124 has a dot size about 50-60 nm. It is worth explaining that, the inventors find that the metallic core wire 121 exhibits the best conductivity when the dot size of the intersection nano dot 124 is controlled between 20 nm and 1000 nm.

(19) FIG. 6 also shows electron microscope images of nano metal wires, and images (a), (c) and (c) in FIG. 6 are captured by using the electron microscope under different resolving powers of 50 nm, 10 nm and 2 nm. Moreover, image (b) and image (c) are obtained by zoom in the part of structure of the image (a) marked by a dashed rectangular framework. From images (b) and (c), it can clearly see a transition layer 122 is formed between the metallic core wire 121 and the protection layer 123. It needs to further explain that, because the AgNW dispersion 2 shown in FIG. 4A often consists of an A solution containing PVP (Poly(vinyl pyrrolidone)) and a B solution containing AgNO3, the composition of the transition layer 122 is verified as AgAg2OPVPTiO2 after related composition analysis is completed. So that, the data of FIG. 6 have proved that the metal compound for forming the transition layer 122 is constituted by a second manufacturing material (Ag), a second oxide of the metal (Ag2O), a PVP (Poly(vinyl pyrrolidone)), and the first oxide (TiO2).

(20) As the engineers skilled in the fabrication of AgNW know, most of AgNWs are produced by way of reducing AgNO.sub.3 to silver clusters and subsequently spreading the silver clusters to silver nano wires by the use of dispersant. So that, it needs to know that the AgNW dispersions 2 supplied by different manufactures may be produced according to different composition formulas. On the other hand, the inventors find different manufacturing process conditions would make the transition layer 122 be formed by another composition distinguishing from above-mentioned AgOC; i.e., the metal compound for forming the transition layer 122 is constituted by a second manufacturing material (Ag), oxygen and carbon.

(21) Continuously, please refer to FIG. 7, where a data curve plot of time of thermal process versus resistance ratio is provided. The data of FIG. 7 are obtained from the conventional touch panel 10 (as FIG. 1 shows) been treated with thermal process under different temperature. FIG. 8 also show a data curve plot of time of thermal process versus resistance ratio, wherein the data of FIG. 8 are obtained from the novel transparent conductive film 1 (as FIG. 2 shows) been treated with thermal process under different temperature. From FIG. 7, it can find that the high temperature (>200 C.) thermal process leads to an abrupt increase in the sheet resistance of the nano wires 103 of the touch panel 10 due to the low thermal resistance of the AgNW. On the contrary, from FIG. 8, it can find that there has no abrupt increase occurring in sheet resistance of the nano metal wires 120 even though the novel transparent conductive film 1 has been treated with thermal process under a high temperature exceeding 200 C. Furthermore, the data of FIG. 8 have proved that the thermal resistance of the transparent conductive film 1 disclosed by the present invention is up to 400 C.

(22) Please refer to FIG. 9, which shows a plot diagram including curves of wavelength versus transmittance and curves of wavelength versus luminous intensity. The basic information of curves A, B, C, D, A, and B are integrated in following Table (1).

(23) TABLE-US-00001 TABLE (1) Curve Decriptions A Curve of wavelength versus transmittance measured from the conventional touch panel 10 (as FIG. 1 shows), wherein at least one metal mesh layer is formed on transparent substrate 100 of the touch panel 10. B Curve of wavelength versus transmittance measured from the novel transparent conductive film 1 (as FIG. 2 shows), wherein the protection layer 123 of the nano metal wires 120 is TiO.sub.2 with 7-nm thickness. C Curve of wavelength versus transmittance measured from the novel transparent conductive film 1 (as FIG. 2 shows), wherein the protection layer 123 of the nano metal wires 120 is TiO.sub.2 with 13.5-nm thickness. D Curve of wavelength versus transmittance measured from the novel transparent conductive film 1 (as FIG. 2 shows), wherein the protection layer 123 of the nano metal wires 120 is TiO.sub.2 with 21-nm thickness. A Curve of wavelength versus luminous intensity measured from a white light emitted by a conventional LED device. B Curve of wavelength versus luminous intensity measured under the condition of using the white light emitted by the conventional LED device to illuminate the transparent conductive film 1 of the present invention.

(24) After finishing the data comparison between curves A, B, C, and D, it is able to find that, in spite of the transmittance of this novel transparent conductive film 1 does reduce with the increase of the protection layer's 123 thickness, the transparent conductive film's 1 transmittance still exceeds 70%. Moreover, the comparison result of curves A and B exhibits that the transparent conductive film can filter part of blue light portion out of the white light by 20-30%.

(25) Therefore, through above descriptions, the transparent conductive film provided by the present invention has been introduced completely and clearly; in summary, the present invention includes the advantages of:

(26) (1) Differing from conventional metal mesh substrates are mainly constituted by silver nanowires (AgNW), the present invention particularly designs a nano metal wire consisting of a metallic core wire, a transition layer and a protection layer, and further develops a transparent conductive film consisting of a substrate and a metal mesh layer; wherein the metal mesh layer is constituted by the said nano metal wires. It is worth describing that, a variety of experimental data prove that the thermal resistance of this novel transparent conductive film is up to 400 C.; moreover, experimental data also exhibit that the transparent conductive film can filter part of blue light portion out of a white light by 20-30%.

(27) (2) On the other hand, besides being applied in the fabrication of the products having touch panel, this novel transparent conductive film can also replace the traditional ITO substrate to be applied in the manufacture of organic solar cells.

(28) The above description is made on embodiments of the present invention. However, the embodiments are not intended to limit scope of the present invention, and all equivalent implementations or alterations within the spirit of the present invention still fall within the scope of the present invention.