Electrochromic film and an electrochromic device comprising the same

Abstract

An electrochromic film and an electrochromic device including the electrochromic film are disclosed. The electrochromic film includes an electrochromic layer and a passivation layer on one side of the electrochromic layer. The coloration level of the electrochromic film is different from the coloration level of the passivation layer. The film may change optical properties as a result of electrochromism according to an electrochemical reaction. The electrochromic film and the electrochromic device have improved electrochromism, excellent durability, excellent color-switching speed, and stepwise control of optical properties.

Claims

1. An electrochromic film, comprising: an electrochromic layer; and a passivation layer on one side of the electrochromic layer, wherein the passivation layer can be colored and bleached in use by an electrochemical reaction, wherein the passivation layer comprises a metal oxynitride that comprises two or more metals selected from Ti, Nb, Mo, Ta and W, wherein the passivation layer has a coloration level different from a coloration level of the electrochromic layer, and wherein the coloration level is a minimum magnitude (absolute value) of a voltage which is applied in use to a layer capable of electrochromism to cause color change.

2. The electrochromic film according to claim 1, wherein the coloration level of the passivation layer is higher than the coloration level of the electrochromic layer.

3. The electrochromic film according to claim 1, wherein the electrochromic layer comprises a reducing electrochromic material or an oxidizing electrochromic material.

4. The electrochromic film according to claim 1, wherein the electrochromic layer comprises a reducing electrochromic material and the reducing electrochromic material comprises an oxide of Ti, Nb, Mo, Ta or W.

5. The electrochromic film according to claim 1, wherein the metal oxynitride comprises Mo and Ti.

6. The electrochromic film according to claim 5, wherein the metal oxynitride is 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.

7. The electrochromic film according to claim 1, wherein the passivation layer has a thin film density (ρ) of 15 g/cm.sup.3 or less.

8. The electrochromic film according to claim 1, wherein the passivation layer has a thickness of 150 nm or less.

9. An electrochromic device comprising a first electrode layer; an electrolyte layer; the electrochromic film according to claim 1; and a second electrode layer sequentially.

10. The electrochromic device according to claim 9, wherein the electrolyte layer, the passivation layer and the electrochromic layer are present sequentially.

11. The electrochromic device according to claim 10, wherein the first electrode layer and the second electrode layer each independently comprise a transparent conductive compound, a metal mesh or an OMO (oxide/metal/oxide).

12. The electrochromic device according to claim 11, wherein the second electrode layer comprises the OMO (oxide/metal/oxide).

13. The electrochromic device according to claim 11, wherein the OMO (oxide/metal/oxide) comprises an upper layer and a lower layer, and the upper layer and the lower layer each independently comprise an oxide of Sb, Ba, Ga, Ge, Hf, In, La, Se, Si, Ta, Se, Ti, V, Y, Zn, Zr or an alloy thereof.

14. The electrochromic device according to claim 13, wherein the upper layer has a thickness in a range of 10 nm to 120 nm and a visible light refractive index in a range of 1.0 to 3.0, and wherein the lower layer has a thickness in a range of 10 nm to 100 nm and a visible light refractive index in a range of 1.3 to 2.7.

15. The electrochromic device according to claim 13, wherein the OMO (oxide/metal/oxide) further comprises a metal layer between the upper layer and the lower layer, and the metal layer comprises Ag, Cu, Zn, Au, Pd or an alloy thereof.

16. The electrochromic device according to claim 15, wherein the metal layer has a thickness in a range of 3 nm to 30 nm and a visible light refractive index of 1 or less.

17. The electrochromic device according to claim 9, wherein the electrolyte layer comprises a compound that comprises one or more monovalent cations of H.sup.+, Li.sup.+, Na.sup.+, K.sup.+, Rb.sup.+ or Cs.sup.+.

18. The electrochromic device according to claim 9, further comprising an ion storage layer between the first electrode layer and the electrolyte layer, wherein the ion storage layer comprises an electrochromic material having a coloring property different from that of the electrochromic material contained in the electrochromic layer.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a graph showing an appearance in which a laminate with a light transmission characteristic comprising a passivation layer of the present application is driven without lowering durability when a voltage of ±5V is applied.

(2) FIG. 2 is a graph relating to driving characteristics of a device. Specifically, FIG. 2(a) is a graph showing an appearance in which the charge quantity of the device of Example 1 changes with increasing cycles, and FIG. 2(b) is a graph showing an appearance in which the charge quantity of the device of Comparative Example 1 changes with increasing cycles.

(3) FIG. 3 is a graph relating to driving characteristics of a device. Specifically, FIG. 3(a) is a graph enlarging and showing changes of electric currents and charge quantities measured according to Example 2 in a specific cycle section (second unit time), and FIG. 3(b) is a graph enlarging and showing changes of electric currents and charge quantities measured according to Comparative Example 2 in a specific cycle section.

(4) FIG. 4 is a graph showing optical characteristics of the electrochromic device of the present application in which the transmittance can be adjusted stepwise according to the applied voltage.

(5) FIG. 5 is a diagram of one embodiment of an electrochromic film (100).

(6) FIG. 6 is a diagram of an embodiment of an electrochromic device (1000).

(7) FIG. 7 is a diagram of an embodiment of an electrochromic device (1000).

BEST MODE

(8) 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: Confirmation of Light Transmission Characteristic of Passivation Layer Containing Metal Oxynitride

Production Example 1

(9) Production of laminate: 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. 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.

(10) Measurement of physical properties: 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).

Production Example 2

(11) A passivation layer was formed in the same manner as in Production 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 3

(12) A passivation layer was formed in the same manner as in Production 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 4

(13) A passivation layer was formed in the same manner as in Production 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.

(14) TABLE-US-00001 Table 1 Transmittance 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

(15) From Table 1, it can be deduced that the oxynitride layers of Production Examples 2 to 4 have very low transmittance, but the oxynitride layer containing an oxynitride of Production Example 1 has transmittance of about 90%. The oxynitride layer of Production Example 1 having a high light transmission characteristic is suitable as a member for an electrochromic device.

Experimental Example 2: Confirmation of Electrochromic Characteristics of Passivation Layer

(16) The laminate (glass/ITO/oxynitride (Mo.sub.aTi.sub.bO.sub.xN.sub.y)) (half-cell) produced in Production Example 1 was immersed in an electrolytic solution containing LiClO.sub.4 (1M) 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 electrochromic times thus measured upon coloring and bleaching are as described in Table 2.

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

(18) TABLE-US-00002 TABLE 2 Colored Bleached Driving Charge Quantity Peak Current T Elapsed T Elapsed Potential (mC/cm.sup.2) (mA) (%) Time (s) Peak Current (%) Time (s) ΔT ±5 V 60 107 30 25 118 61 13 31 ±4 V 50 88 38 72 92 60 13 92 ±3 V 40 68 45 19 88 60 17 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.

(19) As in Table 2, it can be confirmed that the laminate of Production Example 1 has electrochromic characteristics (coloring) depending on the applied voltage. On the other hand, FIG. 1 is a graph recording an appearance in which the laminate of Production Example 1 is driven (electrochromic) when the driving potential is ±5V.

Experimental Example 3: Comparison of the Driving Time (Cycling) and the Usable Level of the Electrochromic Film and the Electrochromic Device Comprising the Same

Example 1

(20) An electrochromic film comprising a Mo.sub.aTi.sub.bO.sub.xN.sub.y layer (passivation layer) having the same elemental content ratio as the oxynitride of Production Example 1, a WO.sub.3 layer (electrochromic layer), and an OMO electrode layer sequentially, was produced. 100 ppm of an electrolytic solution containing LiClO.sub.4 (1M) and propylene carbonate (PC) and a potentiostat device were prepared and a voltage of −1V was applied for 50 seconds to insert Li.sup.+ into the Mo.sub.aTi.sub.bO.sub.xN.sub.y layer and the WO.sub.3 layer. It was confirmed that the WO.sub.3 layer was colored in a color of blue series. At this time, it was confirmed that the content of Li.sup.+ present per cm.sup.2 of the WO.sub.3 layer was included in the range of 1.0×10.sup.−8 mol to 1.0×10.sup.−6 mol, and the content of Li.sup.+ present per cm.sup.2 of the Mo.sub.aTi.sub.bO.sub.xN.sub.y layer was included in the range of 5.0×10.sup.−9 mol to 5.0×10.sup.−7 mol.

(21) Thereafter, a laminate of Prussian blue (PB) and ITO was bonded to the film together via a GPE (gel polymer electrolyte) in the form of a film. The produced electrochromic device has a laminate structure of OMO/WO.sub.3/Mo.sub.aTi.sub.bO.sub.xN.sub.y/GPE/PB/ITO.

(22) While a bleaching voltage and a coloring voltage were repeatedly applied to the produced device at a constant cycle, the change in charge quantity of the device with time was observed. The bleaching voltage per cycle was applied at (+) 1.0V for 50 seconds and the coloring voltage was selected in the range of (−) 1.0 to (−) 3V and applied for 50 seconds. The results are as shown in FIG. 2(a).

Comparative Example 1

(23) An electrochromic device was equally produced, except that the Mo.sub.aTi.sub.bO.sub.xN.sub.y layer was not included, and the change in charge quantity of the device was observed in the same manner. The results are as shown in FIG. 2(b).

(24) From FIG. 2(b), it can be confirmed that in the case of the device of Comparative Example, the driving of about 500 cycles is the limit. However, as in FIG. 2(a), it can be confirmed that in the device of Example, no degradation in performance is observed even if it is driven for 2.5 times or more relative to Comparative Example. It is determined that as the Mo.sub.aTi.sub.bO.sub.xN.sub.y layer of the device of Example prevents deterioration of the adjacent OMO or WO.sub.3, this is a result in which the durability of the device is improved.

(25) On the other hand, with respect to the electrochromic device, the level at which cycling can be performed in a state where no damage occurs to the device upon driving the device is driven is referred to as a usable level of the device. Unlike Comparative Example, the charge quantity does not decrease in Example comprising the Mo.sub.aTi.sub.bO.sub.xN.sub.y layer even if 1,000 cycling or more is performed, and thus it can be said that the usable level has been improved as compared to Comparative Example 1.

Experimental Example 4: Comparison of Electrochromic Time of the Electrochromic Film and the Electrochromic Device Comprising the Same

Example 2

(26) Using a Solidspec 3700 instrument, the charge quantity and current of the device were measured at the time when the coloring and bleaching change was made to some extent during the experiment performed in Example 1. The results are as shown in FIG. 3(a). In the graph of FIG. 3(a), the X axis means time.

Comparative Example 2

(27) For the device of Comparative Example 1, the charge quantity and current of the device were measured in the same manner as in Example 2. The results are as shown in FIG. 3(b).

(28) Unlike FIG. 3(b), it can be confirmed that FIG. 3(a) shows steep peaks of the charge quantity and the current. Specifically, FIG. 3(b) shows the time required for the charge quantity and the current to converge to a specific value in a range of approximately 20 seconds to 30 seconds, but FIG. 3(a) shows the time within 10 seconds. This means that the color-switching speed in the device of Example is fast as compared to the device of Comparative Example.

Experimental Example 4: Confirmation of Function to Finely Control Transmittance in the Electrochromic Film and the Electrochromic Device Comprising the Same

Example 3

(29) For the device of Example 1, −1V, −2V, and −3V were applied stepwise as the coloration level, and 0.5V was applied as a bleaching potential. The transmittance and color at each voltage measured using a Solidspec 3700 instrument are as shown in Table 3 and FIG. 4 below.

(30) TABLE-US-00003 TABLE 3 Applied Voltage Transmittance State (V) (%) Color Bleaching 0.5 45.74  (pastel) Coloring −1 23.12  (blue) −2 6.23  (dark blue) −3 3.41  (greenish blue)

(31) From Table 3 and FIG. 4, it can be confirmed that the film and the electrochromic device of the present application comprising two layers having different coloration levels have light transmittance capable of being adjusted stepwise, and in particular, when both the electrochromic layer and the passivation layer are colored, they have a very high light blocking property. Specifically, it can be confirmed that while the electrochromic layer comprising WO.sub.3 is colored to light blue from the time of −1V application and the passivation layer comprising Mo and Ti is colored to dark gray after the time of −2V application, very low light transmittance is observed.