TRANSPARENT CONDUCTIVE FILM

Abstract

Described herein is a transparent conductive film including (a) a first laminate including at least two layers containing TiO.sub.2, ZrO.sub.2 or HfO.sub.2, and a layer containing an organic compound in between the two layers containing TiO.sub.2, ZrO.sub.2 or HfO.sub.2, (b) a metal layer, and (c) a second laminate including at least two layers containing ZnO, a layer containing an organic compound between the two layers containing ZnO, and a metallic dopant other than zinc.

Claims

1. A transparent conductive film comprising (a) a first laminate comprising at least two layers containing TiO.sub.2, ZrO.sub.2 or HfO.sub.2, and a layer containing an organic compound in between the two layers containing TiO.sub.2, ZrO.sub.2 or HfO.sub.2, (b) a metal layer, and (c) a second laminate comprising at least two layers containing ZnO, a layer containing an organic compound between the two layers containing ZnO, and a metallic dopant other than zinc.

2. The transparent conductive film according to claim 1, wherein the layers containing TiO.sub.2, ZrO.sub.2 or HfO.sub.2 have a thickness of 1 to 10 nm.

3. The transparent conductive film according to claim 1, wherein the layers containing ZnO have a thickness of 1 to 10 nm.

4. The transparent conductive film according to claim 1, wherein the metal layer contains Al, Cu, Ag, or Au.

5. The transparent conductive film according to claim 1, wherein the metal layer has a thickness of 3 to 30 nm.

6. The transparent conductive film according to claim 5, wherein the organic compound is an organic thiol.

7. The transparent conductive film according to claim 1, wherein the first laminate has a thickness of 5 to 40 nm.

8. The transparent conductive film according to claim 1, wherein the film further comprises a transparent flexible substrate.

9. The transparent conductive film according to claim 1, wherein the film has a sheet resistance of 200 S2/sq or less.

10. The transparent conductive film according to claim 1, wherein the film has a resistivity of 0.02 Ω.Math.cm or less.

11. The transparent conductive film according to claim 1, wherein a sheet resistance of the film increases by less than 10% after bending the film for 500 times around a radius of 1 cm.

12. A process for preparing a transparent conductive film comprising depositing on a substrate (a) a first laminate comprising at least two layers containing TiO.sub.2, ZrO.sub.2 or HfO.sub.2, and a layer containing an organic compound in between the two layers containing TiO.sub.2, ZrO.sub.2 or HfO.sub.2, (b) a metal layer, and (c) a second laminate comprising at least two layers containing ZnO, a layer containing an organic compound between the two layers containing ZnO, and a metallic dopant other than zinc.

13. The process according to claim 12, wherein the deposition is performed by atomic layer deposition.

14. The process according to claim 13, wherein the deposition is performed at a temperature of 100 to 220° C.

15. A method of using the film according to claim 1, the method comprising using the film as an electrode in an opto-electronic device.

Description

EXAMPLES

[0075] Substrate Preparation

[0076] Polymer film substrates were cut from polyethylene terephtalate (PET) films (thickness: 125 μm). PET polymer film substrates were cleaned with acetone, ethanol, de-ionized water, and blow-dried with nitrogen to remove contaminants.

[0077] Characterization

[0078] The thickness of layers containing zinc oxide were measured using spectroscopic ellipsometer (FS-1 multi-wavelength ellipsometer, Film Sense). The film morphology was investigated by atomic force microscopy (AFM, XE-100). The conductivity of the films was measured using four-point-probe technique (HP4155C, Agilent Technologies). UV-visible spectra were obtained using UV-VIS spectrometer (UV-VIS 8453, Agilent Technologies).

Example 1 (Comparative)

[0079] TiO.sub.2 was deposited onto PET substrates using titanium(IV) chloride (TiCl.sub.4) and de-ionized water (H.sub.2O) as ALD precursors. Argon (Ar) served as both a carrier and a purging gas. The DEZ and H.sub.2O were evaporated at 20° C. The cycle consisted of 1 s exposure to DEZ, 5 s Ar purge, 1 s exposure to H.sub.2O and 5 s Ar purge. The total flow rate of Ar was 100 sccm. During this procedure, the temperature was kept at 100° C. under the pressure at 400 mbar. The cycle is performed for 875 times yielding a TiO.sub.2 film of 35 nm thickness.

[0080] An Ag layer was deposited on the TiO.sub.2 film by thermal evaporation.

[0081] Zinc oxide containing layers were deposited onto the Ag layer using diethylzinc (DEZ) and de-ionized water (H.sub.2O) as ALD precursors. Argon (Ar) served as both a carrier and a purging gas. The DEZ and H.sub.2O were evaporated at 20° C. The cycle consisted of 1 s exposure to DEZ, 5 s Ar purge, 1 s exposure to H.sub.2O and 5 s Ar purge. The total flow rate of Ar was 100 sccm. During this procedure, the temperature was kept at 100° C. under the pressure at 400 mbar. The growth rate of ZnO thin film by ALD method was 1.5 Å/cycle. The cycle is performed for 233 times.

[0082] Subsequently, a layer containing an organic compound is made using trimethyl aluminum (TMA, Sigma Aldrich: 99%) and 4-mercaptophenol (4MP, Sigma Aldrich: 97%) as precursors. The reaction temperature is lowered to 145° C. Ar served as both a carrier and a purging gas. The TMA and 4MP were evaporated at 20° C. and 80° C., respectively. The ALD cycle consisted of 1 s exposure to TMA, 5 s Ar purge, 5 s exposure to 4MP, 60 s Ar purge, 1 s exposure to TMA and 5 s Ar purge. This cycle was performed once.

Example 2 (Comparative)

[0083] On a PET substrate a TiO.sub.2 film and a Ag film was deposited as in example 1. Zinc oxide containing layers were deposited onto the Ag layer using diethylzinc (DEZ) and de-ionized water (H.sub.2O) as ALD precursors. Argon (Ar) served as both a carrier and a purging gas. The DEZ and H.sub.2O were evaporated at 20° C. The cycle consisted of 1 s exposure to DEZ, 5 s Ar purge, 1 s exposure to H.sub.2O and 5 s Ar purge. The total flow rate of Ar was 100 sccm. During this procedure, the temperature was kept at 100° C. under the pressure at 400 mbar. The growth rate of ZnO thin film by ALD method was 1.5 Å/cycle. The cycle is performed for 233 times.

[0084] Subsequently, a layer containing an organic compound is made using trimethyl aluminum (TMA, Sigma Aldrich: 99%) and 2,3-dimercapto-1-propanol (DMP, Sigma Aldrich: 98%) as precursors. The reaction temperature is lowered to 145° C. Ar served as both a carrier and a purging gas. The TMA and 4MP were evaporated at 20° C. and 80° C., respectively. The ALD cycle consisted of 1 s exposure to TMA, 5 s Ar purge, 5 s exposure to 4MP, 60 s Ar purge, 1 s exposure to TMA and 5 s Ar purge. This cycle was performed once.

[0085] The deposition process for the zinc oxide containing layer and the layer containing an organic compound as described before is alternatingly performed for 14 times yielding a second laminate with a thickness of 35 nm.

Example 3 (Inventive)

[0086] On a PET substrate a first laminate is made by first depositing TiO.sub.2 layers using titanium(IV) chloride (TiCl.sub.4) and de-ionized water (H.sub.2O) as ALD precursors. Argon (Ar) served as both a carrier and a purging gas. The DEZ and H.sub.2O were evaporated at 20° C. The cycle consisted of 1 s exposure to DEZ, 5 s Ar purge, 1 s exposure to H.sub.2O and 5 s Ar purge. The total flow rate of Ar was 100 sccm. During this procedure, the temperature was kept at 100° C. under the pressure at 400 mbar. The growth rate of TiO.sub.2 thin film by ALD method was 1.5 Å/cycle. The cycle is performed for 266 times.

[0087] Subsequently, a layer containing an organic compound is made using titanium(IV) chloride (TiCl.sub.4) and 2,3-dimercapto-1-propanol (DMP, Sigma Aldrich: 98%) as precursors. The reaction temperature is lowered to 145° C. Ar served as both a carrier and a purging gas. The TiCl.sub.4 and DMP were evaporated at 20° C. and 80° C., respectively. The ALD cycle consisted of 1 s exposure to TiCl.sub.4, 5 s Ar purge, 5 s exposure to DMP, 60 s Ar purge, 1 s exposure to TiCl.sub.4 and 5 s Ar purge. This cycle was performed once.

[0088] The deposition process for the TiO.sub.2 containing layer and the layer containing an organic compound as described before was alternatingly performed for 7 times yielding a first laminate with a thickness of 19 nm.

[0089] On the first laminate, a Ag layer as in example 1 and a second laminate as in example 2 was deposited with the difference that the second laminate had a thickness of 40 nm because the zinc oxide containing layer and the layer containing an organic compound as described before is alternatingly performed for 16 times.

Example 4 (Inventive)

[0090] Example 3 was repeated with the first difference that the first laminate had a thickness of 24 nm because the deposition of the TiO.sub.2 containing layer and the layer containing an organic compound as described before was alternatingly performed for 11 times. The second difference is that the second laminate had a thickness of 45 nm because the zinc oxide containing layer and the layer containing an organic compound as described before is alternatingly performed for 18 times.

[0091] Sheet Resistance

[0092] The sheet resistance of the films obtained in the examples 1 to 4 were measured after deposition, after bending 500 times and 1000 times around a radius of 0.5 cm.

TABLE-US-00001 Initial Sheet Sheet Resistance Sheet Resistance Resistance (500 times (1000 times Example in Ω/sq bending) in Ω/sq bending) in Ω/sq 1 25 647 4892 2 20 326 2890 3 23 35 245 4 21 29 95