JP2001133814A - Self-power supply type dimming element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high-speed self-power supply type dimming element which shields harmful UV, converts the UV to electric power and does not require power supply from the outside and to obtain a self-power supply type dimming element which does not impair visibility and has the above functions. SOLUTION: At least a photovoltaic element with a semiconductor layer containing one or more of the group IIIA elements of the Periodic Table and one or more of the group VA elements and a dimming element which varies light transmittance by utilizing electric current or voltage generated by the photovoltaic element are laminated on a transparent electrically conductive substrate to obtain the objective self-power supply type dimming element. The group IIIA elements are preferably Al, Ga and In and the group VA elements are preferably nitrogen. The photovoltaic element is preferably transparent to visible light.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a self-powered dimming device using a photovoltaic device having a novel semiconductor layer on a transparent conductive substrate.

[0002]

2. Description of the Related Art There are various means for appropriately controlling external light and introducing a part of the light into a room, such as a window shade. Recently, research has been conducted to make the window glass itself have a dimming function due to its physical safety and functionality, as well as the sophistication of appearance. Above all, a self-power supply type functional window glass that actively controls to control the indoor temperature is important as a technology relating to energy saving and amenities. These use sunglasses that are colored by ultraviolet rays, electrochromic elements or liquid crystals that can be dimmed by an external electric field, or ceramics that similarly control the scattering of light by an external electric field.

[0003] However, these light control elements have problems such as a very slow response like self-light control type sunglasses using a photochromic material, or a need for external power supply. . These problems can be solved by using a power control dimming element and a solar cell in combination, but the conventional solar cell is opaque to the visible light range, so that There are only methods such as providing a solar cell in a part or providing a solar cell separately from the dimming element, and it is not practical especially in an application where the size is limited.

[0004] Further, since most of the ultraviolet rays of sunlight are harmful to the human body, there has been a case where a window glass is provided with a filter having an ultraviolet ray cut-off effect to block it. Hydrogenated amorphous SiC as a solar cell transparent to visible light
A method using (a-SiC: H) has been proposed.
Journal of Non-Crystallin
e Solids Vol. 198-200 (199
6) Semi-tanspare published in 1163
nt a-SiC: H solarcells for
self-poweredphotovoltaic
(PV) -electrochronic (EC)
The following reports have been made in devices.

[0005] A laminated structure (PV-EC) of a wide-gap amorphous silicon carbide-based solar cell (a-SiC: H) and an electro-optical element is integrally formed on one substrate. In this solar cell element optimized using a-SiC: H, the short-circuit current J _SC is 3.9 m.
At A / cm ² , an open-circuit voltage V _OC of 0.92 V was obtained, and Li
Based on the low-voltage EC device.

[0006] However, a-SiC: H can be made transparent to visible light by increasing the C concentration and widening the band gap.
When the band gap is set to 2.0 eV or more, there is a problem that the photoconductivity is rapidly lowered and the photovoltaic element cannot be functioned. could not. In this report, the electric power required to control a light modulating material based on Li and using a WO ₃ thin film is an open circuit voltage V _OC of 1.0.
V or more and the short-circuit current J _SC is 0.1 mA / cm ² or more.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and achieve the following objects. That is, an object of the present invention is to provide a high-speed self-power-supply type dimming element that blocks harmful ultraviolet rays, converts the ultraviolet rays into electric power, and does not require an external electric power supply. Still another object of the present invention is to provide a self-power supply type dimming element having the above function without impairing visibility by laminating a photovoltaic element transparent to visible light and a dimming element. And

[0008]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that a self-power supply type dimming device in which a photovoltaic device using a wide bandgap semiconductor device is laminated on a dimming device. The inventors have found that the above objects can be achieved, and have completed the present invention. That is, means for solving the above-mentioned problems are as follows. <1> A photovoltaic device having at least a semiconductor layer containing, on a transparent conductive substrate, at least one element selected from Group IIIA elements and one or more elements selected from Group VA elements in the periodic table. And a dimming element that changes light transmittance by using a current or a voltage generated by the photovoltaic element. <2> The group IIIA element in the periodic table is Al,
The self-power supply type light control device according to <1>, wherein the light control device is Ga and In, and the VA group element is nitrogen. <3> The self-power supply type dimming element according to <1> or <2>, wherein the photovoltaic element is transparent to visible light. <4> The method according to <1>, wherein the semiconductor layer contains hydrogen.
3> The self-power supply type dimming element according to any one of <1> to <3>.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The self-power supply type dimming device of the present invention is obtained by laminating at least a photovoltaic device and a dimming device, and further includes other members as necessary. At the time of use, the photovoltaic element is installed in the light incident direction.

[Photovoltaic Element] The photovoltaic element has at least a semiconductor layer on a transparent conductive substrate and, if necessary, other members such as a transparent conductive electrode on the semiconductor layer. Having. The photovoltaic element is transparent to visible light, when laminated on the dimming element,
This is preferable because a self-power supply type dimming element without losing visibility can be obtained. Here, in order to make the photovoltaic element transparent to visible light, the semiconductor layer provided on the transparent conductive substrate only needs to be transparent to visible light.

(Semiconductor Layer) The semiconductor layer contains one or more elements selected from Group IIIA elements and one or more elements selected from Group VA elements in the periodic table. Comprising the components of

—Group IIIA Element— Preferred examples of the Group IIIA element include Al, Ga and In. In the present invention, organometallic compounds containing these elements are preferably used. Specifically, for example, trimethylaluminum, triethylaluminum, t-butylaluminum, trimethylgallium, triethylgallium, t-butylgallium, trimethylaluminum Liquid or solid such as indium, triethylindium, t-butylindium or the like can be vaporized and used alone or in a mixed gas bubbled with a carrier gas. These may be used alone or in combination of two or more. As the carrier gas, H
Noble gases such as e and Ar, single element gases such as H ₂ and N ₂ , hydrocarbons such as methane and ethane, and halogenated carbons such as CF ₄ and C ₂ F ₆ can be used.

—Group VA Element— As the group VA element, nitrogen is particularly preferred. Nitrogen raw materials include N ₂ , NH ₃ , NF ₃ , N ₂ H ₄ ,
A gas such as monomethylhydrazine or dimethylhydrazine or a mixed gas obtained by bubbling these with a carrier gas can be used. As the carrier gas used here, those exemplified above can be used.

The atomic ratio of the group IIIA element to the group VA element is preferably 0.5: 1.0 to 1.0: 0.5. If the ratio is outside this range, the number of parts taking the zincblende type in the bond between the group IIIA element and the group VA element is reduced, so that the number of defects increases and the element does not function as a good photovoltaic element. is there.

-Other components- -Hydrogen- The semiconductor layer preferably contains hydrogen. The hydrogen concentration is preferably 50 atom% or less. Layers (hereinafter,
The hydrogen concentration in the “film” may be 50 atoms
%, The electrical properties are degraded, the mechanical properties such as hardness are reduced, the film is liable to be oxidized, and the weather resistance is sometimes deteriorated. The absolute value of the hydrogen concentration can be measured by hydrogen forward scattering (HFS). Further, by simultaneously forming a film on an infrared transparent substrate such as silicon or sapphire at the time of film formation, the hydrogen content can be easily measured by an infrared absorption spectrum.

--P, n control element-- A compound containing an element for controlling p and n can be introduced into the semiconductor layer and doped into the film. The doping gas may be mixed with an organometallic compound containing a Group IIIA element or may be separately introduced. Further, they may be introduced simultaneously with the organometallic compound or may be introduced continuously.

As an n-type element, a group IA (IUPA)
Li of group C according to the revised 1989 inorganic chemical nomenclature of 1989, Li, group IB (group 11 according to the revised 1989 inorganic chemical nomenclature of IUPAC), Cu, Ag, Au, IIA (IUPAC) Mg of group 2 according to the revised 1989 inorganic chemical nomenclature, Zn of group IIB (group 12 according to the revised 1989 inorganic chemical nomenclature of IUPAC), Zn, group IVA (I
According to the revised version of UPAC's 1989 inorganic chemical nomenclature, the family number is 14) C, Si, Ge, Sn, Pb, VIA group (IUP
According to the AC's revised 1989 inorganic chemical nomenclature, the family number is 1
6) S, Se, Te can be used. Among them, C, Si, Ge, and Sn are preferable from the viewpoint of controllability of charge carriers.

Examples of the p-type element include IA group Li, N
a, K, IB group Cu, Ag, Au, IIA group Be, M
g, Ca, Sr, Ba, Ra, IIB group Zn, Cd, H
g, IVA group C, Si, Ge, Sn, Pb, VIA group (I
Cr, M of the S, Se, Te, VIB groups (family numbers according to the revised version of UPAC's 1989 inorganic chemical nomenclature 16) (family numbers according to the IUPAC revised 1989 inorganic chemical nomenclature 6)
o, W, VIII group Fe (group number according to IUPAC revised 1989 inorganic chemical nomenclature 8), Co (IUPAC 19
1989 Inorganic chemical nomenclature revised edition, family number 9), Ni
(The family number according to the revised version of IUPAC's 1989 inorganic chemical nomenclature is 10). Above all, Be, M
g, Ca, Zn, and Sr are preferred from the viewpoint of controllability of charge carriers.

As the i-type element, the same element as the p-type element can be used at a low concentration.

In addition, it is necessary to prevent hydrogen in the film from binding to the dopant and inactivating the dopant, and the hydrogen for passivating the defect level is more likely to be IIIA than the dopant.
From the viewpoint of selectively bonding to the group III element and the VA element, n
C, Si, Ge, and Sn are particularly preferable as the elements for the mold, and Be, Mg, and C are particularly preferable as the elements for the p-type.
a, Zn, and Sr are preferable, and Be, Mg, Ca, Zn, and Sr are particularly preferable as the i-type element.

For doping, n-type Si
H ₄ , Si ₂ H ₆ , GeH ₄ , GeF ₄ , and SnH ₄ can be used for p-type BeH ₂ , BeCl ₂ , BeCl ₄ , cyclopentadienyl magnesium, dimethyl calcium, dimethyl strontium, dimethyl zinc, diethyl zinc For the i-type, the same compound as the p-type element can be used in a gaseous state. Further, the doping element can be diffused into the film as it is, or can be taken into the film as ions.

-Laminated Structure- The photovoltaic element of the present invention is manufactured by forming a semiconductor layer on a transparent or conductively transparent substrate. At this time, a Schottky-type photovoltaic element can be obtained by forming a semiconductor layer having a single-layer structure, and higher efficiency can be achieved by forming a stacked structure such as a pn diode structure and a pin structure. Can be.
In order to make it transparent, ultraviolet or violet short-wavelength light is used, and the light amount itself is not so large. For effective use, films having different optical gaps can be laminated.

FIG. 1 is a schematic diagram showing an example of a photovoltaic device according to the present invention. This photovoltaic element comprises a semiconductor layer 21 and a transparent conductive electrode 2 on a transparent conductive substrate 20.
2 are provided in this order, and the semiconductor layer 21 has a single-layer structure. FIG. 2 is a schematic configuration diagram showing another example of the photovoltaic element according to the present invention. This photovoltaic element also has a semiconductor layer 21 and a transparent conductive electrode 22 provided on a transparent conductive substrate 20 in this order.
Has a laminated structure. That is, the semiconductor layer 21 has a structure in which the n-type semiconductor layer 25, the i-type semiconductor layer 24, and the p-type semiconductor layer 23 are sequentially stacked from the transparent conductive substrate 20 side. When the semiconductor layer has a stacked structure, the semiconductor layer may be stacked in the order of a p-type semiconductor layer, an i-type semiconductor layer, and an n-type semiconductor layer from the transparent conductive substrate side.

The composition and thickness of a semiconductor layer containing at least one element selected from Al, Ga, and In having different optical gaps, nitrogen, and hydrogen can be controlled by changing the concentrations of the source gas and the carrier gas. The flow rate may be changed, and the discharge energy may be changed. For controlling the film thickness, it is preferable to control the film formation time. The semiconductor layer is made of Al, G
a, an n-type or p-type semiconductor containing one or more elements selected from In, nitrogen and hydrogen,
Further, a film p ⁺ or n ⁺ layer doped with a high concentration may be inserted, or a film p ⁻ or n ⁻ layer doped with a low concentration may be inserted.

Further, for transparency and formation of a barrier, p-type,
Each of the i-type and n-type layers has different Al _xGa_yIn_z(X =
0-1.0, y = 0-1.0, z = 0-1.0)
Al, Ga, In and N
In addition, each of the p-type, i-type, and n-type_xGa_y
In_zN: H (x = 0 to 1.0, y = 0 to 1.0, z =
0-1.0).

-Optical gap and the like-The optical gap of the semiconductor layer is 2.8 in order to transmit a main part of visible light and to make it substantially colorless or pale transparent.
It is preferably eV or more. The optical gap of the film is
It can be arbitrarily changed depending on the mixing ratio of the group IIIA element. On the basis of GaN: H, when it is higher than 3.5 eV, it can be increased to about 6.5 eV by adding Al, and when it is lower than 3.2 eV, it is transparent by adding In. The measurement wavelength range can be changed as it is. From the plot of the square of the wavelength (eV) and the absorption coefficient (αe),
It is obtained from the extrapolated point of the low energy linear part.
Alternatively, a wavelength (eV) having an absorption coefficient of 10,000 cm ^-1
It may be. The absorption coefficient can be obtained by using the absorbance excluding the background or by measuring the film thickness dependency.

The semiconductor layer that can be used here includes, for example, a transmission electron beam diffraction pattern having no ring-shaped diffraction pattern and a halo pattern completely lacking long-range order. A ring-shaped diffraction pattern was observed, a bright spot was found therein, and only a bright spot was found. In such a layer, almost no peak is often obtained in X-ray diffraction measurement for observing a wider range than transmission electron beam diffraction. Also, in the transmission electron beam diffraction pattern, many bright spots are observed together with the ring-shaped diffraction pattern, and even if there are almost only spot-shaped bright spots, X
In a line diffraction measurement, the peak intensity of a polycrystal or the strongest peak is weaker than that of a single crystal, and peaks of other weak plane orientations may be mixed. In some cases, it is an entirely bright point and shows an X-ray diffraction spectrum consisting of almost one plane orientation.

The crystal size of the group III-V compound semiconductor is from 5 nm to 5 μm, and can be measured by X-ray diffraction, electron diffraction, shape measurement using an electron micrograph of a cross section, or the like. Also, the absorbance of the photoconductive member is 400 n.
0.8 or less at m and 0.5 or less at 500 nm are preferable for colorless or light-colored transparency. The extinction coefficient is a value obtained by measuring the amount of absorption with a spectrophotometer and dividing the film thickness by a natural logarithmic system. The amount of light transmission at 400 nm is 50,000 cm ^-1 or less in order to be regarded as transparent. Is preferably 3
It is more preferably at most 000 cm ^-1 . These values substantially correspond to an optical gap of 2.8 eV or less.

(Transparent Conductive Substrate) The substrate used for the photovoltaic element is transparent and has conductivity, but if the base material constituting the substrate is conductive or semiconductive. It can be used without conducting treatment, and if the base material is insulating, it can be used as a substrate by subjecting the insulating base material to conducting treatment. Further, the substrate used for the photovoltaic element may be crystalline or amorphous. As the transparent base material constituting the transparent conductive substrate, a transparent material, for example, glass, quartz, sapphire, MgO, SiC, ZnO, TiO ₂ , LiF, Ca
Transparent inorganic material F ₂ and the like; fluorine resin, polyester,
A film or plate of a transparent organic resin such as polycarbonate, polyethylene, polyethylene terephthalate, and epoxy resin; an optical fiber, a selfoc optical plate, and the like can be used. When the light-transmitting substrate is insulating, for example, a transparent conductive material such as ITO, zinc oxide, tin oxide, lead oxide, indium oxide, and copper iodide is used, and vapor deposition, ion plating, sputtering, etc. A film is formed by the method of the above and subjected to a conductive treatment, or
Metals such as aluminum, stainless steel, nickel, chromium, or gold, silver, copper, etc., or alloys thereof are formed by vapor deposition, sputtering, ion plating, etc., to a degree that they are translucent, and subjected to a conductive treatment. Is done.

(Other members)-Transparent conductive electrode-On the semiconductor layer, a transparent conductive electrode can be provided as the other member. As the transparent conductive electrode, for example, ITO, zinc oxide, tin oxide, lead oxide,
Using a transparent conductive material such as indium oxide and copper iodide,
One formed by a method such as vapor deposition, ion plating, or sputtering, or one formed by thinning a metal such as aluminum, nickel, chromium, gold, silver, or copper or an alloy thereof to such a degree as to be translucent by vapor deposition or sputtering. Used.

(Method of Manufacturing Photovoltaic Element) Next, a method of manufacturing a photovoltaic element constituting the self-power supply type dimming element of the present invention will be described with reference to the drawings. FIG. 3 shows a schematic configuration of an apparatus for manufacturing a photovoltaic element according to the present invention. This photovoltaic element manufacturing apparatus comprises a cylindrical reactor 1, first and second raw material activation-supply units 13 and 14 continuous with the reactor 1 through an upper opening, a reactor 1 and a lower unit. An exhaust pipe 2 which is continuous through the opening and exhausts gas in the reactor 1, a substrate holder 3 arranged in the reactor 1 and supporting a substrate, and a substrate installation of the substrate holder 3 And a heater 4 arranged on the opposite side to the surface side.

The first and second raw material activation-supply units 13,
Numeral 14 denotes cylindrical quartz tubes 5 and 6, which communicate with the reactor 1 and are arranged radially outside the reactor 1, respectively, and communicate with the opposite sides of the quartz tubes 5, 6 opposite to the reactor 1. And gas introduction pipes 9 and 10 which are provided. First raw material activation-supply unit 1
Reference numeral 3 denotes a microwave waveguide 8 further disposed so as to intersect with the quartz tube 5, and a gas introduction tube continuous with the quartz tube 5 on the reactor 1 side from the intersection of the quartz tube 5 and the microwave waveguide 8. 11 is provided. The microwave waveguide 8 has a housing shape,
A quartz tube 5 penetrates through it. In the second raw material activating / supplying unit 14, a high frequency coil 7 is used instead of the microwave discharge tube 8, and the high frequency coil 7 is a quartz tube 6
And connected to a high-frequency oscillator (not shown).

The gas introduction pipes 9, 10, 11, 12 of the first and second raw material activating / supplying units 13, 14 are respectively connected to a cylinder or the like (not shown) for supplying raw material gas. ing. Further, gas introduction pipes 11, 1
2 is connected to a flow controller (not shown) for intermittently supplying the raw material gas. Further, the microwave waveguide 8 is connected to a microwave oscillator using a magnetron (not shown), and discharges in the quartz tube 5. Further, the exhaust pipe 2 is connected to a pump as an exhaust means (not shown), and the inside of the reactor 1 can be exhausted to a substantially vacuum.

In this apparatus, for example, N ₂ is used as a nitrogen element source and introduced into the quartz tube 5 from the gas introduction tube 9. A microwave is supplied to a microwave waveguide 8 connected to a microwave oscillator (not shown) using a magnetron, and a discharge is generated in the quartz tube 5. For example, H ₂ is introduced into the quartz tube 6 from another gas introduction tube 10. A high frequency is supplied from a high frequency oscillator (not shown) to the high frequency coil 7 to generate a discharge in the quartz tube 6. By introducing, for example, trimethylgallium from the gas introduction pipe 12 from the downstream side of the discharge space, a gallium nitride semiconductor can be formed on the transparent conductive substrate.

The substrate temperature is about 100 to 600 ° C.
When the substrate temperature is high and / or when the flow rate of the group IIIA element source gas is small, microcrystals tend to be formed. When the substrate temperature is lower than 300 ° C., when the flow rate of the group IIIA source gas is small, microcrystals are liable to be formed.
When the temperature is higher than ° C, microcrystals are likely to be formed even when the flow rate of the group IIIA element source gas is higher than the low temperature condition. Further, for example, when H ₂ discharge is performed, microcrystallization can be performed more than when H ₂ discharge is not performed. Instead of trimethylgallium, for example, an organometallic compound containing indium and aluminum can be used, or can be mixed. Further, these organometallic compounds are supplied to the gas introduction pipe 1
It may be introduced separately from one.

A gas containing one or more elements selected from C, Si, Ge, and Sn, or a gas containing Be, Mg, C
a, a gas containing at least one element selected from Zn and Sr is supplied to the downstream side of the discharge space (the gas introduction pipe 11 or the gas introduction pipe 1).
By introducing from 2), an amorphous, microcrystalline, or crystalline semiconductor layer of any conductivity type such as n-type and p-type can be obtained. In the case of C, carbon of an organometallic compound may be used depending on conditions.

In the above apparatus, active nitrogen or active hydrogen formed by discharge energy may be controlled independently, or a gas such as NH ₃ containing both nitrogen and hydrogen atoms may be used. Further, H ₂ may be added. Further, a condition under which active hydrogen is liberated from the organometallic compound may be used. By doing so, activated group IIIA element atoms and nitrogen atoms are present in a controlled state on the transparent conductive substrate, and hydrogen atoms convert methyl groups or ethyl groups to methane or ethane. Since it is an inert molecule, carbon does not enter even at a low temperature, and an amorphous film, a microcrystalline film, or a crystalline film in which film defects are suppressed can be generated.

The method for activating the raw material activating / supplying unit in the above apparatus may be any of a direct current discharge, a low frequency discharge, a high frequency discharge, a microwave discharge, an electron cyclotron resonance method, and a helicon plasma method.
Also, a heating filament may be used. These are 1
The species may be used alone, or two or more species may be used in combination.
In the case of a high-frequency discharge, an inductive coupling type or a capacitive type may be used. When two or more activation methods are used in one space, it is necessary to make it possible to generate a discharge at the same pressure at the same time, and the inside of the microwave waveguide (or the high-frequency waveguide) and the inside of the quartz tube (or the reaction And a pressure difference between them. When these pressures are the same, the excitation energy of the active species can be greatly changed by using different raw material activating means, for example, microwave discharge and high-frequency discharge, whereby the film quality can be controlled. . In the present invention, it is also possible to form a film in an atmosphere in which at least hydrogen is activated, such as a reactive vapor deposition method, ion plating, and reactive sputtering.

In the photovoltaic element of the present invention, a current can be taken out between the transparent conductive electrodes. A photovoltaic element provided with a semiconductor layer containing at least one element selected from Al, Ga, and In and nitrogen is completely transparent and has a large optical gap. Two to three times larger than the element, and as a result, the amount of electricity available in the same area is large. Further, it has an advantage that it has a long life because of its excellent light resistance, heat resistance and oxidation resistance.

[Light control element] The self-power supply type light control element of the present invention is a light control element that changes light transmittance by using the photovoltaic element and a current or a voltage generated by the photovoltaic element. It can be obtained by laminating an optical element.
The self-power supply type dimming element of the present invention can be arbitrarily and optionally turned on and off by an operation switch or the like attached to the element.
/ Off can be performed. In the present invention, a charging device may be provided, and the photovoltaic element uses a dimming element, and can be charged whenever the window is lit by light even when the light is blocked. . Known materials such as an electrochromic material and a liquid crystal can be used for the dimming device.

(Liquid Crystal) The liquid crystal is a material widely used for digital watches and displays, and can be obtained at relatively low cost. In particular, use in a place where there is no problem even if the transmitted light is polarized is preferable. Examples of the liquid crystal used in the light control element include a nematic liquid crystal, a cholesteric liquid crystal, a ferroelectric liquid crystal, a polymer liquid crystal, and a polymer dispersed liquid crystal. Among them, a polymer-dispersed liquid crystal, which is easy to produce in a twisted nematic liquid crystal structure in terms of response speed and modulation voltage, is preferable.

On the semiconductor layer of the photovoltaic element, or when a transparent conductive electrode is provided on the semiconductor layer, a dimming element made of a liquid crystal thin film is formed on the transparent conductive electrode. For this, a conventionally known coating method can be used. Specifically, a method of sandwiching a spacer and injecting it between another transparent electrode and a spin coating method can be preferably used. The thickness of the thin film of the liquid crystal,
0.3-100 μm is preferred, and 0.7-20 μm is more preferred. When the thickness is less than 0.3 μm, the degree of modulation of the liquid crystal layer is low, and the non-uniformity may increase. On the other hand, when the thickness is more than 100 μm, the driving voltage becomes insufficient and May not cause light effect.

(Electrochromic Material) An electrochromic material which develops a color by an oxidation-reduction reaction by electrons is:
The production cost is low and suitable for reactions such as window materials several times a day and for applications such as eyeglasses. Almost all transition metal oxides and hydroxides can be used as the electrochromic material. Among them, those having a reductive coloring property such as WO ₃ , MoO ₃ , Nb ₂ O ₅ , Prussian blue, Ni (O
H) n, Ir (OH) n and the like, which are oxidative and color-forming, are suitable in terms of color-forming characteristics. The Prussian blue changes from colorless to blue at about 0.2 V, and changes from blue to green at about 1.0 V. In addition, the Ni (OH) n and Ir (O
H) n changes from colorless to blue. These materials are formed by a vacuum evaporation method, and oxidation and reduction can be controlled using a solid or liquid electrolyte. The voltage required for each reaction is around 1 V, and the current is several tens to several hundreds μA / cm ² . In the present invention, if a semiconductor layer having the same area as the dimming element is used, WO
Driving with materials other than ₃ is also possible.

A material obtained by laminating an ion storage material such as V ₂ O ₅ with an ion conductive material such as MgF ₂ sandwiched between the electrochromic material and the solid electrolyte may be used. If drying of the electrolyte in question does not occur, a colorless liquid electrolyte that is easy to manufacture may be used. By laminating such an electrolyte on a dimming material, one dimming element is obtained.

On the semiconductor layer of the photovoltaic element, or when a transparent conductive electrode is provided on the semiconductor layer, a light modulating element comprising a thin film of an electrochromic material is formed on the transparent conductive electrode. For formation, for example, electrophoretic deposition, sputtering, vacuum evaporation, CDV, MOCVD, etc. can be used. The thickness of the thin film of the electrochromic material is preferably 0.2 to 40 μm,
0.3 to 10 μm is more preferable. The thickness is 0.2 μm
When the thickness is less than 40 μm, the light-shielding ability may be insufficient. On the other hand, when the thickness exceeds 40 μm, the driving voltage may be insufficient, and the light-shielding ability may decrease and the response time may increase.

When the photovoltaic element and the dimming element are stacked, the transmittance at the time of irradiation with ultraviolet rays depends on whether the dimming element side is connected to the anode or the cathode of the photovoltaic element. Can be increased or decreased.

[0047]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited to these examples.
In addition, FIGS. 4 and 5 show schematic configuration diagrams of the self-power supply type dimming devices manufactured in Example 1 and Example 2, respectively.

(Example 1) A transparent conductive substrate 32 was formed by depositing a thin film 30 of ITO on a surface of Corning 7059 glass 31 by a sputtering method. This is placed on the substrate holder 3, and the reactor 1 is connected through the exhaust pipe 2.
After evacuating the inside, the substrate 32 is heated to 380 ° C. by the heater 4.
Heated. First raw material activation-supply unit 13 for N ₂ gas
200 mm into the quartz tube 5 having a diameter of 25 mm from the gas introduction tube 9.
0 sccm, and 2.4 through the microwave waveguide 8.
A microwave of 5 GHz was set to an output of 250 W, matching was performed with a tuner, and discharge was performed. The reflected wave at this time was 0W. On the other hand, H ₂ gas is activated to the second raw material−
1000 sccm was introduced from the gas introduction tube 10 of the supply unit 14 into the quartz tube 6 having a diameter of 30 mm, and 13.56 MHz high-frequency discharge was performed. The output of the high-frequency power was 100 W, and the reflected wave was 0 W. In this state, 1 sccm of trimethylgallium (TMGa) vapor held at 0 ° C. was introduced through a mass flow controller while bubbling using nitrogen as a carrier gas from the gas introduction pipe 12 of the second raw material activation-supply unit 14. Further, cyclopentadienyl magnesium using nitrogen as a carrier gas was introduced at 2 sccm. At this time, the reaction pressure measured by a Baratron vacuum gauge was 110.4 Pa. The film was formed for 180 minutes to produce a 0.2 μm i-type GaN: H film (semiconductor layer). As described above, the III-V
A semiconductor layer 33 containing a group III compound semiconductor was formed, and a transparent photovoltaic element was manufactured.

In order to form an electrode for closing the circuit later, the ITO thin film 3 is formed so that the semiconductor layer 33 is not short-circuited.
It was formed slightly smaller than 0. Next, on one side, ITO
A thin film 35 is formed, and a Corning 7059 glass 36 on which a polarizing plate 37 is stacked on the other surface is stacked so that the ITO thin films 30 and 35 face each other with a spacer (not shown) interposed therebetween. Inject, thickness 10
A μm thin film of nematic liquid crystal was formed. These two I
The TO thin films 30 and 35 are connected to the wiring 38 from the end of the ITO electrode.
For electrical connection. Here, the nematic liquid crystal 3
4 and the polarizing plate 37 function as a light control element. The nematic liquid crystal 34 has the property of rotating the plane of polarization by applying a voltage of about 1V. The output voltage of the transparent photovoltaic element was less than 1 V under sunlight, and was sufficient as a driving voltage.

On the other hand, when the composition of the film formed under the same conditions as the above GaN film was measured by RBS (Rutherford Backscattering), the Ga / N ratio was 0.9 and almost stoichiometric. . Also, the hydrogen content by HFS measurement was 2 atom% or less. Hydrogen was slightly contained in this GaN film as Ga-H and NH by IR spectrum measurement. Ga-N absorption is 70 cm ^-1.
Was found to be crystalline. The electron diffraction spectrum was a ring to spot pattern, and the X-ray diffraction spectrum was mainly composed of a (0002) peak. The optical gap was 3.2 eV, the light absorption coefficient at 400 nm was 5000 cm ⁻¹ , and the film was completely transparent. Au was formed by a vacuum evaporation method on a film produced under the same conditions as the GaN film, and a transparent electrode was provided. Next, when a 325 nm ultraviolet light of a He-Cd laser was irradiated, a photocurrent (I _SC ) of 4 mA / cm ² flowed at 0 V. The open circuit voltage (V _OC ) was 1.2V.

(Example 2) A transparent conductive substrate 32 was formed by forming a thin film of ITO on a surface of a Corning 7059 glass 31 at a thickness of 2000 ° by a sputtering method. On this substrate 32, a semiconductor layer 33 was formed in the same manner as in Example 1. Next, a 400 nm thick ITO thin film 39 (transparent conductive electrode) is formed on the semiconductor layer 33 by sputtering.
Was formed to produce a transparent photovoltaic element. The RF output of the sputter was 1 kW, the reflected wave at this time was about 10 W, and the film formation time was 20 minutes. The ITO thin films 30 and 39 had different compositions, and sufficient electric power could be extracted from the transparent photovoltaic device. Here, another transparent conductive material such as TiO ₂ may be used.

Using the ITO thin film 39 as an electrode, an electrochromic thin film 40 was formed by electrophoretic deposition by the following method. That is, for the electrochromic thin film, a colloidal solution of WO ₃ was used at a concentration of 4%, and the substrate on which the ITO thin film 39 was formed was immersed in this solution,
Using the thin film 39 as an electrode by electrophoresis, 1.2 V,
A WO film having a thickness of 2 μm was formed under a condition of 1.4 mA for 10 minutes.
_Three films were formed. Next, on the front side of the Corning 7059 glass 36 on which the ITO thin film 35 was formed, a solid electrolyte, MgF ₂ , was formed by a 0.7 μm sputtering method to form a transparent electrolyte 41.
It was stuck with 0. The two ITO thin films 30 and 35 are I
The end of the TO electrode was electrically connected by a wiring 38.
Here, the electrochromic thin film 40 and the transparent electrolyte 4
1 functions as a light control element. This electrochromic dimming device has a voltage of 1 V or more and a current of 0.1 mA / c.
it was possible to operate in m ² or more. This dimming device was able to operate sufficiently with the electromotive voltage (V _OC ) and photocurrent (I _SC ) generated by ultraviolet light in fine weather.

[0053]

According to the present invention, it is possible to provide a high-speed self-power-supply type dimming element that blocks harmful ultraviolet rays, converts the ultraviolet rays into electric power, and does not require an external electric power supply. it can. Furthermore, according to the present invention, there is provided a self-power supply type dimming element having the above function without impairing visibility by laminating a photovoltaic element transparent to visible light and a dimming element. Can be.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an example of a photovoltaic device constituting a self-power supply type dimming device of the present invention.

FIG. 2 is a schematic configuration diagram showing another example of a photovoltaic element constituting the self-power supply type dimming element of the present invention.

FIG. 3 is a schematic configuration diagram illustrating an example of an apparatus for manufacturing a photovoltaic element constituting a self-power supply type dimming element of the present invention.

FIG. 4 is a schematic configuration diagram showing a self-power supply type dimming device manufactured in Example 1.

FIG. 5 is a schematic configuration diagram showing a self-power supply type dimming device manufactured in Example 2.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reactor 2 Exhaust pipe 3 Substrate holder 4 Heater 5, 6 Quartz tube 7 High frequency coil 8 Microwave waveguide 9-12 Gas introduction pipe 13 First raw material activation-supply unit 14 Second raw material activation-supply unit Reference Signs List 20 transparent conductive substrate 21 semiconductor layer (III-V compound semiconductor) 22 transparent conductive electrode 23 p-type semiconductor layer 24 i-type semiconductor layer 25 n-type semiconductor layer 30 ITO thin film 31 Corning 7059 glass 32 transparent conductive substrate 33 semiconductor Layer 34 Nematic liquid crystal 35 ITO thin film 36 Corning 7059 glass 37 Polarizer 38 Wiring 39 ITO thin film 40 Electrochromic thin film 41 Transparent electrolyte

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2K001 AA08 BA07 CA01 CA08 DA03 EA01 5F051 AA08 AA16 BA03 CA02 CA03 CA04 CA14 DA03 DA04 FA03 FA04

Claims (4)

[Claims] 1. A photovoltaic device comprising at least a semiconductor layer containing at least one element selected from Group IIIA elements and one or more elements selected from Group VA elements in a periodic table on a transparent conductive substrate. A self-powered dimming device, comprising: a power device and a dimming device that changes light transmittance by using current or voltage generated by the photovoltaic device. 2. The group IIIA element in the periodic table,
2. The self-powered dimming device according to claim 1, wherein the self-powered dimming device is Al, Ga, and In, and the VA group element is nitrogen. 3. The self-powered dimming device according to claim 1, wherein the photovoltaic device is transparent to visible light. 4. The self-powered dimming device according to claim 1, wherein said semiconductor layer contains hydrogen.