A method for improving amorphous WO 3 Thin Film Optical Transmittance Method

Abstract

The invention discloses a method for improving the optical transmittance of an amorphous WO3 film. The amorphous WO3 film is fully irradiated and treated with visible light or ultraviolet light, so that the optical transmittance of the WO3 film can be effectively improved. While improving the optical transmittance of the WO3 film and greatly improving the transparency of the sample, its electrochromic efficiency or optical modulation is also improved. The method is simple and effective, the preparation cost is low, and it has broad application prospects.

Description

Technical Field

[0001] The invention belongs to the technical field of electrochromic thin film materials, and in particular relates to a method for improving the optical transmittance of an amorphous WO3 thin film. Background Art

[0002] WO3 film is an important electrochromic material that can be used in the fields of construction, transportation, aerospace, etc. It is of great significance for energy conservation and environmental protection. Electrochromism refers to the stable and reversible changes in the optical properties of materials such as reflectivity and transmittance under a certain external electric field, which manifests as reversible changes in color and transparency on a macro scale.

[0003] Usually, the main indicators for evaluating the electrochromic performance of a material include color change efficiency, color change response time, color storage time, cycle life, etc. Among them, color change efficiency is the most important indicator of electrochromic materials, which can be described by the difference in transmittance between the maximum coloring state and the fading state at a certain wavelength in the visible light band, namely optical modulation (OM).

[0004] Therefore, to improve the color change efficiency of WO3 thin film, the key lies in how to improve the optical transmittance of WO3 thin film in the faded state, or reduce the optical transmittance of WO3 thin film in the colored state. Generally speaking, the optical transmittance of the film is closely related to its microstructure, and the microstructure depends on the preparation process and post-processing method of the film. Therefore, it is very necessary to find an effective process method to further optimize the color change efficiency or optical transmittance of WO3 thin film. Summary of the invention

[0005] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0006] In view of the above problems and / or the problems existing in the prior art, the present invention is proposed.

[0007] Therefore, the purpose of the present invention is to overcome the deficiencies in the prior art and provide a method for improving the optical transmittance of amorphous WO3 thin films.

[0008] In order to solve the above technical problems, the present invention provides the following technical solutions: comprising:

[0009] Amorphous WO3 thin films were prepared by magnetron sputtering using high-purity W target as target material and ITO conductive glass as substrate.

[0010] The amorphous WO3 film is fully irradiated with visible light or ultraviolet light to improve the optical transmittance of the amorphous WO3 film.

[0011] As a preferred solution of the method for improving the optical transmittance of the amorphous WO3 thin film of the present invention, wherein: the amorphous WO3 thin film prepared by the magnetron sputtering method is realized by using a magnetron sputtering coating system, including:

[0012] The chamber of the magnetron sputtering coating system was evacuated to a vacuum of 5.0×10 -3 After Pa, high-purity argon gas is introduced, the chamber pressure is adjusted through a high valve, and then the RF power supply is turned on and the power is adjusted, and sputtering deposition is carried out at room temperature.

[0013] As a preferred solution of the method for improving the optical transmittance of amorphous WO3 thin film described in the present invention, wherein: the chamber pressure is adjusted to 0.3 Pa, the power is 100 W, and the deposition time is 1.5 h.

[0014] As a preferred solution of the method for improving the optical transmittance of the amorphous WO3 thin film of the present invention, the amorphous WO3 thin film prepared by the magnetron sputtering method has an amorphous structure and a thickness of 100 nm.

[0015] As a preferred solution of the method for improving the optical transmittance of amorphous WO3 thin film described in the present invention, wherein: the visible light is provided by an LED lamp bead light source, wherein the light source power is 50W and the operating voltage is 30V.

[0016] As a preferred solution of the method for improving the optical transmittance of amorphous WO3 thin film described in the present invention, wherein: the energy distribution of the visible light spectrum is between 400 and 840 nm.

[0017] As a preferred solution of the method for improving the optical transmittance of amorphous WO3 thin film described in the present invention, the ultraviolet light is provided by a high-pressure mercury lamp light source, wherein the light source power is 250W and the operating voltage is 135V.

[0018] As a preferred solution of the method for improving the optical transmittance of amorphous WO3 thin film described in the present invention, wherein: the energy distribution of the ultraviolet light spectrum is between 315 and 450 nm, and the main wavelength is 365 nm.

[0019] As a preferred solution of the method for improving the optical transmittance of amorphous WO3 thin film of the present invention, wherein: the sufficient irradiation treatment is carried out in a dark room for 24 hours.

[0020] As a preferred solution of the method for improving the optical transmittance of amorphous WO3 thin film described in the present invention, the method can improve the optical transmittance of amorphous WO3 thin film products by 27%, and at the same time improve the optical modulation by 9%, wherein the optical transmittance is the value of the amorphous WO3 thin film product at a wavelength of 676.2nm.

[0021] Beneficial effects of the present invention:

[0022] The present invention provides a method for improving the optical transmittance of a WO3 thin film. The optical transmittance of the WO3 thin film can be improved by fully irradiating the WO3 thin film with visible light or ultraviolet light. While improving the optical transmittance of the WO3 thin film and greatly improving the transparency of the sample, its electrochromic efficiency or optical modulation is also improved. The method is simple and effective, has a low preparation cost, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0024] Figure 1 The transmittance curves and optical modulation of the amorphous WO3 thin film in the colored state c1 and the faded state c2 in Example 1 are shown.

[0025] Figure 2 The transmittance curves and optical modulation of the amorphous WO3 thin film in the colored state a1 and the faded state a2 after visible light irradiation in Example 2;

[0026] Figure 3 The transmittance curves and optical modulation of the amorphous WO3 thin film in the colored state b1 and the faded state b2 after ultraviolet light irradiation in Example 3;

[0027] Figure 4 is an optical transmittance curve of the amorphous WO3 thin film in Examples 1 to 3 of the present invention;

[0028] Figure 5 The scanning electron microscope images of the amorphous WO3 thin films in Examples 1 to 3 of the present invention are shown. DETAILED DESCRIPTION

[0029] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0030] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0031] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0032] The magnetron sputtering coating system used in the present invention is a JGP500A magnetron sputtering coating system produced by Shenyang Keyou Vacuum Technology Co., Ltd.

[0033] The present invention characterizes and analyzes the optical modulation of the film through an electrochromic testing system.

[0034] The target material used in the present invention is a high-purity W target with a size of Purity 99.999%;

[0035] The substrate used in the present invention is ITO conductive glass: size 25×40×0.7 mm, resistance 3.5Ω / □.

[0036] Example 1

[0037] This embodiment provides a method for preparing an amorphous WO3 thin film. The following embodiments all take the amorphous WO3 thin film prepared in this embodiment as the research object.

[0038] Cleaning the ITO conductive glass substrate: sequentially place the ITO conductive glass substrate into 99.5% analytical pure acetone, 99.7% analytical pure anhydrous ethanol and deionized water with a resistivity of 18.2 MΩ〃cm, ultrasonically clean it for 15 to 20 minutes, and dry it for later use;

[0039] A high-purity W target and a cleaned ITO substrate were installed in the magnetron sputtering coating system, and the chamber was evacuated to 5.0×10 -3 After the chamber reaches 0.5 Pa, high-purity argon gas with a flow rate of 20 sccm and a purity of 99.999% is introduced, and the high valve is adjusted to maintain the chamber pressure at 0.3 Pa;

[0040] The RF power supply was turned on and the power was adjusted to 100 W. The amorphous WO3 thin film sample with a thickness of 100 nm was obtained by sputtering deposition at room temperature for 1.5 h.

[0041] The optical transmittance and optical modulation were characterized and analyzed using the electrochromic test system. Figure 1 As shown, the optical transmittance of the amorphous WO3 film before discoloration, in the faded state and in the colored state without light irradiation at a wavelength of 676.2nm is 68%, 53% and 3% respectively, and the optical modulation is 50%.

[0042] Example 2

[0043] The amorphous WO3 thin film sample prepared in Example 1 was placed in a dark room, and an LED lamp with a power of 50 W and an operating voltage of 30 V was used to generate visible light with a wavelength of 400 to 840 nm to fully irradiate the thin film sample for 24 hours.

[0044] The optical transmittance and optical modulation were characterized and analyzed using the electrochromic test system. Figure 2 As shown, the optical transmittance of the amorphous WO3 film before discoloration, in the faded state and in the colored state after visible light treatment at a wavelength of 676.2 nm is 80%, 80% and 21% respectively, and the optical modulation is 59%.

[0045] Example 3

[0046] The amorphous WO3 thin film sample prepared in Example 1 was placed in a dark room, and a high-pressure mercury lamp with a power of 250 W and an operating voltage of 135 V was used to generate ultraviolet light with a wavelength of 365 nm as the center of the spectrum, and the thin film sample was fully irradiated for 24 hours.

[0047] The optical transmittance and optical modulation were characterized and analyzed using the electrochromic test system. Figure 3 As shown, after UV treatment, the optical transmittance of the amorphous WO3 film at 676.2 nm before discoloration, in the faded state and in the colored state is 81%, 78% and 23% respectively, and the optical modulation is 55%.

[0048] Table 1 Transmittance and optical modulation of amorphous WO3 films under different treatment conditions

[0049]

[0050]

[0051] As shown in Table 1 and Figure 4As shown, the method of using visible light or ultraviolet light to fully irradiate the amorphous WO3 film proposed in the present invention has a very significant effect on improving the optical transmittance of the amorphous WO3 film. The optical transmittance of the WO3 film before the electrochromic treatment is increased from 68% to 80%-81%, with an increase of 12%-13%, increasing the transparency of the sample; after the electrochromic treatment, the optical transmittance of the faded state is increased from 53% to 78%-80%, with an increase of 25%-27%; the optical transmittance of the colored state is increased from 3% to 21%-23%, with an increase of 18%-20%; and the optical modulation is correspondingly increased from 50% to 55%-59%, with an increase of 5%-9%. Among them, the reason for the increase in optical modulation is that the increase in the optical transmittance of the faded state is greater than the increase in the optical transmittance of the colored state, and the reason why the increase in the optical modulation is not large is that the optical transmittance of the colored state is also increased.

[0052] like Figure 5 As shown, a, b, and c are SEM images of samples irradiated with visible light, irradiated with ultraviolet light, and not irradiated with light, respectively. It can be seen that the surface morphology of the sample after visible light treatment has no obvious change, while the sample particles after ultraviolet light treatment are finer, and the agglomeration of large particles has been greatly improved. At the same time, the WO3 film after visible light and ultraviolet light treatment still maintains an amorphous structure, indicating that the method of the present invention will not cause obvious adverse effects on the surface morphology, microstructure, etc. of the amorphous WO3 film, which is very important for the performance stability and service life of the amorphous WO3 film material and device.

[0053] In summary, the method provided by the present invention for treating amorphous WO3 thin film by fully irradiating with visible light or ultraviolet light can effectively improve the optical transmittance of the WO3 thin film, and while improving the optical transmittance of the WO3 thin film and greatly improving the transparency of the sample, its electrochromic efficiency or optical modulation is also improved. The method is simple and effective, with low preparation cost, and has broad application prospects.

[0054] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for improving the optical transmittance of an amorphous WO3 thin film, characterized in that: include, Amorphous WO3 thin films were prepared by magnetron sputtering using high-purity W target as target material and ITO conductive glass as substrate. The magnetron sputtering method for preparing amorphous WO3 thin film is implemented by using a magnetron sputtering coating system, and the chamber of the magnetron sputtering coating system is evacuated to 5.0×10 -3 After the high-purity argon gas is introduced into the chamber at 0.3 Pa, the chamber pressure is adjusted by a high valve, and then the RF power supply is turned on and the power is adjusted, and sputtering deposition is performed at room temperature. The chamber pressure is adjusted to 0.3 Pa by a high valve, the power is 100 W, and the deposition time is 1.5 h. The prepared amorphous WO3 film has an amorphous structure and a thickness of 100 nm. The amorphous WO3 film is fully irradiated with visible light or ultraviolet light to improve the optical transmittance of the amorphous WO3 film, wherein the visible light is provided by an LED lamp bead light source, the light source power is 50 W, the operating voltage is 30 V, and the visible light spectrum energy distribution is 400~840 nm; The ultraviolet light is provided by a high-pressure mercury lamp light source, the light source power is 250 W, the operating voltage is 135 V, the ultraviolet light spectrum energy distribution is 315 ~ 450 nm, the main wavelength is 365 nm; The full irradiation treatment was carried out in a dark room for 24 h; The method can improve the optical transmittance of the amorphous WO3 thin film product by 27% and improve the optical modulation by 9%, wherein the optical transmittance is the value of the amorphous WO3 thin film product at a wavelength of 676.2 nm.

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