Light-transmitting film and an electrochromic device comprising the same

Abstract

A light-transmitting film and a device including the light-transmitting film are disclosed. The light-transmitting film includes an oxynitride containing two or more metals selected from Ti, Nb, Mo, Ta and W, and having light transmittance of 60% or more. The oxynitride may be represented by Formula 1, which is Mo.sub.aTi.sub.bO.sub.xN.sub.y where a>0, b>0, x>0, y>0, 0.5<a/b<4.0, and 0.005<y/x<0.02. The film has a light transmission characteristic, is capable of reversible color-switching depending on the applied voltage, and has excellent durability within a driving voltage range in which the film changes its color.

Claims

1. A light-transmitting film, comprising: an oxynitride represented by Formula 1:
Mo.sub.aTi.sub.bO.sub.xN.sub.y  Formula 1 wherein a represents an elemental content ratio of Mo, b represents an elemental content ratio of Ti, x represents an elemental content ratio of O, and y represents an elemental content ratio of N, where a>0, b>0, x>0, y>0, 0.5<a/b<4.0, and 0.005<y/x<0.02, wherein the film is a variable transmittance film and has a light transmittance of 60% or more in a bleached state.

2. The light-transmitting film according to claim 1, wherein the film has a thickness of 150 nm or less.

3. The light-transmitting film according to claim 1, wherein the film has a visible light refractive index in a range of 1.5 to 3.0.

4. The light-transmitting film according to claim 1, wherein the film has a coloration level of an applied voltage of 2V or more.

5. An electrochromic device comprising an electrode layer; the light-transmitting film according to claim 1 as a first electrochromic layer; and an electrolyte layer.

6. The electrochromic device according to claim 5, comprising a first electrode layer, the electrolyte layer, the first electrochromic layer, and a second electrode layer sequentially.

7. The electrochromic device according to claim 6, further comprising a second electrochromic layer between the first electrode layer and the electrolyte layer.

8. The electrochromic device according to claim 7, wherein the second electrochromic layer comprises an oxidizing electrochromic material.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a graph showing an appearance in which the laminate of Example 1 of the present application is driven without lowering durability when a voltage of ±5V is applied.

(2) FIG. 2 is an electrochromic device according to an embodiment.

(3) FIG. 3 is an electrochromic device according to an embodiment.

(4) FIG. 4 is an electrochromic device according to an embodiment.

BEST MODE

(5) Hereinafter, the present application will be described in detail through Examples. However, the scope of protection of the present application is not limited by Examples to be described below.

Experimental Example 1: Elemental Content of Oxynitride Layer and Comparison of Transmittance Thereof

Example 1

(6) Production of Laminate:

(7) ITO having light transmittance of about 90% was formed on one side of glass having light transmittance of about 98%. Thereafter, a layer of an oxynitride (Mo.sub.aTi.sub.bO.sub.xN.sub.y) containing Mo and Ti was formed to a thickness of 30 nm on the ITO surface (opposite to the glass position) using sputtering deposition (Production Example 1). Specifically, the deposition was performed at a weight % ratio of Mo and Ti targets of 1:1, a deposition power of 100 W and a process pressure of 15 mTorr, and flow rates of Ar, N.sub.2 and O.sub.2 were 30 sccm, 5 sccm and 5 sccm, respectively.

(8) Measurement of Physical Properties:

(9) The content ratio of each element in the oxynitride layer and the transmittance of the laminate were measured and described in Table 1. The elemental content (atomic %) was measured by XPS (X-ray photoelectron spectroscopy) and the transmittance was measured using a haze meter (solidspec 3700).

Comparative Example 1

(10) An oxynitride layer was formed in the same manner as in Example 1, except that the flow rate of nitrogen was 10 sccm at the time of deposition and the content ratios were changed as in Table 1 (Production Example 2).

Comparative Example 2

(11) An oxynitride layer was formed in the same manner as in Example 1, except that the flow rate of nitrogen was 15 sccm at the time of deposition and the content ratios were changed as in Table 1 (Production Example 3).

Comparative Example 3

(12) An oxynitride layer was formed in the same manner as in Example 1, except that the flow rate of nitrogen was 0 sccm at the time of deposition and the content ratios were changed as in Table 1 (Production Example 4).

(13) TABLE-US-00001 TABLE 1 Trans- mittance N Ti O Mo a/b y/x (%) Production 0.6 ± 0.0 13.1 ± 0.2 57.3 ± 0.3 29.5 ± 0.5 2.251908 0.0105 80 Example 1 Production 2.7 ± 0.6 14.4 ± 0.3 44.8 ± 0.9 33.0 ± 0.5 2.291667 0.0603 11 Example 2 Production 3.3 ± 0.4 15.5 ± 0.2 33.5 ± 0.3 33.5 ± 0.4 2.16129 0.0985 5 Example 3 Production not 15.5 ± 0.2 51.6 ± 0.4 32.9 ± 0.3 2.12 — 15 Example 4 detected

(14) From Table 1, it can be deduced that the oxynitride layers of Comparative Examples 1 to 3 have very low transmittance, but the oxynitride layer of Example 1 has transmittance of about 90%. Unlike Comparative Examples, the oxynitride used in Example 1 or the light-transmitting laminate comprising the same can be used as a member for an electrochromic device.

Experimental Example 2: Confirmation of Electrochromic Characteristics

Example 2

(15) The laminate (glass/ITO/oxynitride (Mo.sub.aTi.sub.bO.sub.xN.sub.y)) (half-cell) produced in Example 1 was immersed in an electrolytic solution containing LiClO.sub.4 (IM) and propylene carbonate (PC) and a coloring voltage of −3V and a bleaching voltage of +3V were alternately applied at 25° C. for 50 seconds, respectively. The currents, transmittances and color-switching times upon coloring and bleaching measured over time are as described in Table 2.

(16) In addition, the measurements were performed for ±4V and ±5V, and the results were described in Table 2.

(17) TABLE-US-00002 TABLE 2 Colored Charge Peak Bleached Driving Quantity Current T Elapsed Peak T Elapsed Potential (mC/cm.sup.2) (mA) (%) Time (s) Current (%) Time (s) ΔT ±5 V 60 107 30 25 118 61 13 31 ±4 V 50 88 38 22 92 60 13 22 ±3 V 40 68 45 19 88 60 12 15 Size of laminate (width × length): 2.5 cm × 10 cm Glass sheet surface: 10Ω/□ Charge quantity: measured by potential step chronoamperometry (PSCA) using a potentiostat device. Colored elapsed time (s): the time taken to reach the 80% level of the final coloring state transmittance observed after the elapse (50 s) of the application time of the potential for coloring Bleached elapsed time (s): the time taken to reach the 80% level of the final bleaching state transmittance observed after the elapse (50 s) of the application time of the potential for bleaching Driving potential: a voltage of a predetermined magnitude actually applied for coloring and bleaching of the laminate (half cell). The bleaching potential and the coloring potential are the same in magnitude but different in sign.

(18) As in Table 2, it can be confirmed that the laminate comprising the light-transmitting film of the present application has electrochromic characteristics when a potential having a magnitude of 3V or more is applied.

(19) On the other hand, FIG. 1 is a graph showing an appearance in which the laminate of Example 2 (electrochromic device) is driven when a driving potential of ±5V is applied. It can be confirmed from FIG. 1 that the laminate comprising the light-transmitting film of the present application exhibits uniform cycle characteristics even when a relatively high driving potential is applied, and operates without lowering durability.