JP2014143060A - Semiconductor element showing charge and discharge characteristic - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin-film secondary battery element (a semiconductor element) that has excellent productivity and can be developed to various use applications.SOLUTION: There is provided the semiconductor element in which compound oxide of tin dioxide, magnesium oxide and silicon oxide is formed on a transparent conductive film (a first electrode).

Description

  The present invention relates to a semiconductor element composed of a composite whose optical transmission coefficient is changed by irradiation with ultraviolet rays or application of electric charge, and in particular, printing, optical equipment, recording material, display material, light control material, photosensitive element, clothing, decoration. The present invention relates to a semiconductor element that exhibits photochromic characteristics or electrochromic characteristics suitable for use, and further exhibits charge / discharge characteristics by application of electric charge.

2. Description of the Related Art In recent years, research on reducing the thickness and weight of a secondary battery as a power source and increasing its capacity has been actively conducted in view of an increase in power consumption accompanying the improvement in performance of mobile terminals.
Secondary batteries include secondary batteries that store energy as electrochemical energy using an oxidation-reduction reaction, electrochemical capacitors, and capacitors that can be stored as a change in capacity of an electric double layer.
Secondary batteries include acid-lead batteries, nickel-cadmium batteries, alkaline batteries, nickel-hydrogen secondary batteries, and other lithium-ion secondary batteries that use active materials that are effective for ion insertion reactions. Non-aqueous secondary batteries such as are known.

  Lithium ion secondary batteries are widely used mainly in electronic devices such as portable devices. This is because the lithium ion secondary battery has a higher voltage, a large charge / discharge capacity, and less harmful effects due to the memory effect than a nickel-cadmium secondary battery. Electronic devices are being further reduced in size and weight, and lithium ion secondary batteries that are further reduced in size and weight are required to be mounted on these electronic devices. A conventional lithium ion secondary battery has a structure in which a metal piece or a metal foil is used for both the positive electrode and the negative electrode, which is immersed in an electrolytic solution between both electrodes and covered with a container. Therefore, there is a limit to thinning and miniaturization.

However, recently, in order to enable further reduction in thickness and size, a polymer battery using a gel electrolyte instead of an electrolytic solution and a thin film solid secondary battery using a solid electrolyte have been developed.
The polymer batteries described in Patent Document 1 (Patent No. 3561580) and Patent Document 2 (Patent No. 2934450) cannot be made thinner and smaller than a general lithium ion secondary battery using an electrolyte. However, since a gel electrolyte, a sealing material, and the like are required, the thickness is about 0.1 mm.

  On the other hand, a thin-film solid secondary battery has a configuration in which a current collector thin film, a negative electrode active material thin film, a solid electrolyte thin film, a positive electrode active material thin film, and a current collector thin film are sequentially stacked on a substrate, or a structure by reverse stacking as described above. doing. Thereby, a thin film solid secondary battery can be made very thin compared with a lithium ion secondary battery. Of these, graphite carbon, which is standardly used as a negative electrode active material, is extremely difficult to form a thin film. Even if a thin film can be formed, only a thin film with high resistance and poor adhesion can be obtained. Therefore, it is difficult to use as a negative electrode of a thin-film solid secondary battery. In addition, as a negative electrode material that has recently been examined as an alternative material for graphite carbon, silicon, tin, or their alloy materials are accompanied by volume expansion / contraction during lithium ion insertion and removal, and charge and discharge in thin film solid state secondary batteries. By repeating the above, film peeling tends to occur. Although it is conceivable to use metallic lithium as the negative electrode material as it is, metallic lithium is difficult to handle because it is vulnerable to moisture and oxygen and is easily oxidized.

  Accordingly, metal oxides such as vanadium oxide and niobium oxide are often used as the negative electrode of the thin-film solid secondary battery, which has little volume expansion / contraction during insertion and withdrawal of lithium ions. Patent Document 3 (Japanese Patent No. 3116857) and Patent Document 4 (Japanese Patent No. 3531866) report thin-film solid secondary batteries using vanadium oxide or niobium oxide as a negative electrode. However, vanadium oxide is weak against moisture and oxygen, is not only easily oxidized, but also has toxicity, so that it is difficult to handle it during the manufacturing process or use.

  The thing of patent document 5 (Unexamined-Japanese-Patent No. 2004-179158) uses lithium titanate etc. as oxides other than a silicon or vanadium oxide for a negative electrode layer. This lithium titanate is known not to be distorted in insertion and release of Li ions, and is suitable as a negative electrode material for a thin film solid secondary battery. However, lithium titanate has a slightly smaller charge / discharge capacity compared to niobium oxide, vanadium oxide, etc., and lithium titanate is an insulator, so its electronic conductivity is low and its ionic conductivity is low. There is a problem that the internal resistance is increased and the high-speed charge / discharge characteristics are inferior. Furthermore, when a thin film is formed by a vacuum process such as sputtering, the lithium titanate sintered body has low electrical conductivity and poor thermal conductivity, so not only the sputtering rate is slow, but also the target is easy to break, so a strong power is applied. There is a drawback that the film formation rate becomes extremely slow.

  Secondary batteries that do not involve electrochemical reaction or ion conduction include electric double layer capacitors. However, although these capacitors are excellent in the ability to charge and discharge high-density power in a short time, the energy density is inferior to that of a lithium ion secondary battery.

On the other hand, as a new secondary battery, an oxide semiconductor formed on a conductor is irradiated with light, and an electron trap is formed in the oxide semiconductor accompanying a photoexcitation structure change, to a semiconductor secondary battery (quantum battery). The technology to be applied is developed by Guera Technology Co., Ltd., Hiroshima Oyama and others. (Non-patent document 1 Hiroshima University New Technology Briefing 2010 material, Non-patent document 2 Guera Technology HP.)
According to this technique, it can be expected to be applied as an electrochromic element that causes coloring of the charging layer with charging, and a manufacturing method thereof is disclosed in Patent Document 6 (WO2008 / 053561).
The characteristics of the semiconductor secondary battery are that it is all solid and can be easily thinned, has high energy density, and has high safety and environmental resistance.

  Moreover, as an application of a thin film solid secondary battery, a thin film power supply element that is lightweight and has a small occupied volume can be considered by using it together with a thin film solar battery. As a result, advantages such as weight reduction and no power maintenance are expected as power sources for portable display terminals such as electronic paper and outdoor display terminals.

  As a configuration of the power feeding element, a configuration in which a solar cell and a secondary battery are stacked is generally used in order to improve effective power generation efficiency per unit area of the solar cell. (For example, patent document 7 (Unexamined-Japanese-Patent No. 2011-8976))

As described above, the semiconductor secondary battery has various merits. However, there are problems such as improving charge / discharge characteristics and improving productivity.
An object of the present invention is to provide a thin film secondary battery element (semiconductor element) that solves the above-described problems, has excellent productivity, and can be developed for various uses.

As a result of intensive studies in order to solve the above problems, it has been found that the “semiconductor element” described in the following (1) to (10) can be solved.
(1) “A semiconductor element in which a composite oxide of tin dioxide, magnesium oxide and silicon oxide is formed on a transparent conductive film (first electrode).”
(2) “The composite oxide contains an oxide derived from a composite of a tin carboxy derivative, a magnesium carboxy derivative and a silicon oxide derivative, or a composite of a tin carboxy derivative and a silicon oxide derivative. The semiconductor device according to (1), characterized in that it is characterized.
(3) “The semiconductor element according to (1) or (2), wherein the semiconductor element has a metal plate and / or a ceramic layer on the composite oxide.”
(4) “The second electrode is formed on the metal plate and / or the ceramic layer, and the second electrode has a HOMO level deeper than the first electrode. The semiconductor element according to 3). "
(5) “The semiconductor element according to any one of (1) to (4), wherein a main component of the transparent conductive film is indium oxide.”
(6) “The semiconductor element according to (5) above, wherein the main component of the second electrode is indium oxide.”
(7) The above (1) to (6), characterized in that the composite oxide and the transparent conductive film are sandwiched between a substrate made of metal, glass, or ceramic, and a reinforcing layer bonded to the substrate. A semiconductor device according to any one of the above.
(8) In any one of the above (1) to (7), the atomic ratio of tin and magnesium in the composite oxide is between Sn: Mg = 3: 7 to 1: 9 The semiconductor device described. "
(9) “The semiconductor element according to any one of (2) to (8), wherein the tin carboxy derivative is Sn (O ₂ CCHEt (CH ₂ ) ₃ ) _2. ”
(10) “The semiconductor device according to any one of (2) to (9), wherein the magnesium carboxy derivative is Mg (O ₂ CCHEt (CH ₂ ) ₃ ) _2. ”

As will be understood from the following detailed and specific explanation, it becomes possible to provide a thin film secondary battery element (semiconductor element) that exhibits good charge / discharge characteristics, is excellent in productivity, and can be developed for various uses. .
In addition, since a composite oxide of tin dioxide, magnesium oxide, and silicon oxide is formed on the transparent conductive film (first electrode), a semiconductor element capable of satisfactory charge / discharge can be obtained.
The composite oxide is formed of a composite of a tin carboxy derivative, a magnesium carboxy derivative and a silicon oxide derivative, or a composite of a tin carboxy derivative and a silicon oxide derivative. Since film formation can be performed, productivity can be improved.
Furthermore, by providing a metal plate and / or a ceramic layer on the composite, it is possible to prevent a short circuit and prevent an inflow of reverse current.
Furthermore, a second electrode is formed on the metal plate and / or the ceramic layer, and the second electrode has a deeper HOMO level than the first electrode, so that the movement of electrons is good. Become.
Moreover, regarding a semiconductor element, high transparency and low resistance can be obtained by providing a transparent conductive film whose main component is indium oxide.
Moreover, high transparency and low resistance can be obtained by using indium oxide as the main component of the second electrode.
In addition, the composite film can be satisfactorily held by sandwiching the composite oxide film and the transparent conductive film with a substrate made of metal, glass, or ceramic and having a reinforcing layer bonded to the substrate.
Moreover, what shows a favorable charging / discharging characteristic can be provided because the content atomic number ratio of tin and magnesium is between tin: Mg = 3: 7-1: 9.
The tin carboxy derivative is Sn (O ₂ CCHEt (CH ₂ ) ₃ ) ₂ and the magnesium carboxy derivative is Mg (O ₂ CCHEt (CH ₂ ) ₃ ) ₂ to improve productivity. it can.

It is sectional drawing which shows the structure of the electric field sensitive element which concerns on the Example of this invention. It is a top view which shows the structure of the display device which concerns on the Example of this invention.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

The element structure of the secondary battery used in the present invention will be described.
FIG. 1 is a cross-sectional view of a secondary battery element, and FIG. 2 is a plan view. As shown in FIG. 1, the first electrode 12, the charging layer 13, the hole blocking layer 14, and the second electrode 15 are formed on the substrate 11 in this order.
As shown in FIGS. 1 and 2, since only the electrode layer is patterned in the present invention, the charge layer 13 and the hole block layer 14 are common between adjacent cells. Patterning is an example, and it can be designed in any shape according to desired secondary battery module characteristics.

  Hereinafter, each constituent material and formation process will be described.

  The substrate 11 is made of a material such as glass, thin film metal, or plastic, and for example, alkali-free glass, borosilicate glass, float glass, soda lime glass, polymer resin, or the like can be used. However, when using a substrate having low heat resistance, it is necessary to set the process temperature below that temperature. When using a metal substrate, it is necessary to form an insulating layer to prevent a short circuit.

The first electrode 12 used in the present invention is not particularly limited as long as it is a conductive substance, and known metals, metal oxides, and organic conductive materials can be used.
For example, indium tin oxide (hereinafter referred to as ITO), fluorine-doped tin oxide (hereinafter referred to as FTO), antimony-doped tin oxide (hereinafter referred to as ATO), indium / zinc oxide, niobium titanium oxide And metal such as graphene, CNT (carbon nanotube), Al, Ti, Ag, Au, and Pt, and these may be used alone or in a plurality of layers.

  Although there is no characteristic limitation on the thickness of the first electrode 12, one having a low specific resistance is preferable from the viewpoint of energy density. The film thickness is preferably 5 nm to 1 μm, and more preferably 20 nm to 100 nm.

  As a process for forming the first electrode 12, there are known vacuum film formation such as sputtering and vapor deposition, and film formation methods by various printing methods. In these processes, it is possible to pattern electrodes using a shadow mask or the like. Alternatively, patterning can be performed by a known resist process.

  At the time of forming by printing, it is possible to form a nanoparticle ink of various metals or an organic metal salt complex ink by coating pyrolysis, or a sol-gel method. As the printing process, various methods such as an ink jet method, a dispenser method, and a wet printing method such as a relief plate, offset, gravure, intaglio, rubber plate, and screen printing can be used. A first electrode is obtained through baking of the coating film. When patterning the electrodes, a dedicated plate is formed. Alternatively, in the ink jet method or the dispenser method, patterning can be arbitrarily formed by inputting pattern data.

  The charging layer 13 used in the present invention can be a thin film in which a metal carboxy derivative and an insulating material are mixed. Tin, titanium, and zinc can be used as the metal carboxy derivative. As the insulating material, various thermoplastic resins such as polyimide, various silicon, magnesium oxide, silicon dioxide, alumina and the like can be used.

  As a formation process of the charge layer 13, formation by application thermal decomposition of a nanoparticle ink or an organometallic complex ink of a carboxy derivative and an insulating material, formation by a sol-gel method, or the like is possible. In the case of using various types of silicon or thermoplastic resin as the insulating material, it can be formed by being dissolved in a solvent and mixed with a metal material.

  As a printing process, the same technique as that for the first electrode 12 can be used. Further, from the viewpoint that patterning is not necessary, printing processes such as a dip method, a spray method, a wire bar method, a spin coating method, a roller coating method, and a blade coating method can also be applied.

After the charge layer 13 is formed in contact with the first electrode 12, the structure of the charge layer 13 is changed by ultraviolet irradiation. As a result, the mixed thin film of the carboxy derivative and the insulator is changed into the charge layer 13 that accumulates charges.
The irradiation amount of ultraviolet rays is preferably 48 J or more.

The blocking layer 14 used in the present invention is not particularly limited as long as it is a material that blocks electrons, and a known oxide or organic material can be used.
As the oxide, for example, nickel oxide can be used. As the vacuum process, a sputtering method or the like can be used. Alternatively, nanoparticle ink or organometallic complex ink can be formed by thermal decomposition of coating or by sol-gel method.
As a printing process, the same technique as that for the charging layer 13 can be used.

As the organic material of the block layer 14, various p-type semiconductor materials can be used.
As an example, a polymer such as polythiophene or a low molecular material such as pentacene can be used.
The block layer can be formed by a printing process when a polymer material soluble in an organic solvent is used. In addition, the low molecular weight material can be formed by a process such as vacuum deposition.

  As the material of the second electrode layer 15, the same material and process as those of the first electrode 12 can be applied.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.

[Example 1]
[Fabrication of secondary battery cell Sn: Si]
By preparing a glass substrate with a thickness of 40 mm × 40 mm and a thickness of 0.7 mm as the substrate 11, an ITO film is formed on the glass substrate to a thickness of about 150 nm by a sputtering method through a shadow mask, A first electrode layer 12 was formed. Next, a mixed liquid of 1.68 g of tin 2-ethylhexanoate, 4.43 g of toluene, 0.84 g of ethanolamine, 4.54 g of 2-methoxyethanol, 25 g of IPA, and 1.12 g of silicon oil [TSF433] was prepared.

  This solution was stirred at 80 ° C. for 2 hours under an argon atmosphere, and subsequently stirred at 120 ° C. for 1 hour to complete the solution preparation.

The solution prepared as described above was applied to the ITO surface by a spin coating method, dried, and then baked at 410 ° C. for 1 hour to obtain a mixed film of tin oxide and silicon oil.
Next, the fired film was irradiated with ultraviolet rays. The irradiation intensity was 40 mW / cm ^{2 at} 254 nm and the irradiation time was 5 hours. Thereby, the charge layer 13 was obtained. Through the above process, tin dioxide and silicon oxide were obtained in the charge layer.

  After forming the charge layer, a block layer 14 was formed by subsequently forming a nickel oxide film on the charge layer with a thickness of 140 nm using NiO as a target by sputtering. Furthermore, the second electrode layer 15 was formed by forming an ITO film with a thickness of about 150 nm by sputtering through a shadow mask.

  As a result, as shown in FIG. 1, a secondary battery element in which a charging layer, a block layer, and a second electrode layer were sequentially formed on the first electrode layer was produced. The layout of the manufactured element is shown in FIG. This is a configuration in which three cells are juxtaposed as shown in FIG. The gap between the electrode layers is 3 mm. In each cell, the charge layer and the block layer are common. The active area contributing to charging / discharging is 23 mm × 7 mm.

On the other hand, the homo level of the first electrode was −4.57 eV, and the second electrode was −5.2 eV. This change in energy level appears after UV irradiation.
The charge / discharge characteristics of the cell produced as described above were evaluated.

As the charging voltage, −3 V was applied to the first electrode, and the capacity was 0.77 μAhr / cm ² .
When the potential of the first electrode 12 after charging was measured, an output potential of −1.0 V with respect to the second electrode 15 was shown. Subsequently, when constant current discharge was measured at 10 μA / cm ^{2, the} discharge capacity was 0.38 μAhr / cm ² at a final voltage of −0.1 V.

[Example 2]
[Fabrication of secondary battery cell Sn: Mg: Si]
A cell was fabricated in exactly the same manner as in Example 1, except that 1.65 g of Mg (O ₂ CCHEt (CH ₂ ) ₃ ) ₂ was newly added. In Example 2, magnesium oxide was obtained in the charge layer.

The charge / discharge characteristics of the cell produced as described above were evaluated.
The charging voltage was −3 V applied to the first electrode, and the capacity was 0.72 μAhr / cm ² .
When the potential of the first electrode 12 after charging was measured, an output potential of −0.85 V with respect to the second electrode 15 was shown. Subsequently, when constant current discharge was measured at 10 μA / cm ^{2, the} discharge capacity was 0.18 μAhr / cm ² at a final voltage of −0.1 V.

11 Substrate 12 First electrode 13 Charging layer 14 Block layer 15 Second electrode

Japanese Patent No. 3561580 (Japanese Patent Laid-Open No. 10-74496) Japanese Patent No. 2934450 (JP-A-2-295070) Japanese Patent No. 3116857 (Japanese Patent Laid-Open No. 10-284130) Japanese Patent No. 3531866 (Japanese Patent Laid-Open No. 2002-42863) JP 2004-179158 A WO2008 / 053561 publication JP 2011-8976 A

Hiroshima University New Technology Briefing 2010 materials, Non-patent document 2 Guella Technology, Inc. HP http: // www. guala-tec. co. jp /

Claims (10)

  A semiconductor element, wherein a composite oxide of tin dioxide, magnesium oxide and silicon oxide is formed on a transparent conductive film (first electrode).   The composite oxide contains an oxide derived from a composite of a tin carboxy derivative, a magnesium carboxy derivative, and a silicon oxide derivative, or a composite of a tin carboxy derivative and a silicon oxide derivative. Item 2. The semiconductor element according to Item 1.   The semiconductor element according to claim 1, further comprising a metal plate and / or a ceramic layer on the composite oxide.   The second electrode is formed on the metal plate and / or the ceramic layer, and the second electrode has a HOMO level deeper than that of the first electrode. Semiconductor element.   The semiconductor element according to claim 1, wherein a main component of the transparent conductive film is indium oxide.   The semiconductor element according to claim 5, wherein a main component of the second electrode is indium oxide.   7. The semiconductor device according to claim 1, further comprising a reinforcing layer bonded to the substrate by sandwiching the composite oxide and the transparent conductive film with a substrate made of metal, glass, or ceramic. .   8. The semiconductor element according to claim 1, wherein the atomic ratio of tin and magnesium in the composite oxide is Sn: Mg = 3: 7 to 1: 9. The semiconductor element according to claim ₂ , wherein the tin carboxy derivative is Sn (O ₂ CCHEt (CH ₂ ) ₃ ) ₂ . The semiconductor element according to claim ₂ , wherein the magnesium carboxy derivative is Mg (O ₂ CCHEt (CH ₂ ) ₃ ) ₂ .

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