This invention relates to a reversible coloring and decoloring solid-state device, a reversible conductive property changing solid-state device, a reversible refractive index changing solid-state device, and the applications of these solid-state devices, e.g. a nonradiative display device, a conducting path device and a light waveguide device, wherein the optical and electric properties (the characteristics of coloring and decoloring, conductive property change, and refractive index change) of a WO3 film are reversibly changed rapidly by applying an electric field or irradiating a light with an application of an electric field, and more specifically, a technique for reversibly changing the optical and electric properties which can dramatically improve the characteristics of reversibly changing the above mentioned optical and electric properties and the reliability while the electrolyte for supplying ions to the WO3 film is formed by a solid-state system.
The optical and electric properties of a kind of solid-state materials significantly change by inserting a different kind of atoms into the interstitial gaps by electric excitation or optical excitation. If the inserted atoms can be electrically pulled out from the interstitial gaps and the original condition can be recovered, the optical and electric application can be expanded.
Electrochromic (EC) devices are known as the typical devices which have this effect. EC devices are formed by contacting a thin film of a transition metal compound film with an electrolyte, and the EC devices are colored by applying an electric field of a polarity and are decolored by applying an electric field of the opposite polarity.
The coloring and decoloring are reversible and such coloring and decoloring can be also caused by irradiating an external light to the contacting portion of the transition metal compound film and the electrolyte.
As a result of this operation, an element M is inserted into the gap in the main lattice of the WO3, and a nonstoichiometric compound Mx WO3 which is called tungsten bronze is formed. Where the value of x changes from 0 to 1 depending on the amount of the inserted element M, and the color changes from dark blue to golden yellow depending on the value x. When the value x is large it has a metallic characteristic, and when the value x is small it becomes a semiconductor or an insulator.
In this condition, if a voltage of the opposite polarity is applied to the device 9, positive ions M+ and electrons e− are pulled out from the tungsten bronze, and it returns to the original WO3 thin film 91. The aforementioned reversible process is described by the following equation.
WO3+xM++xe−MxWO3(0≦x≦1)
The inserted element M functions as a color center optically and a donor electrically.
Applications of EC devices to optical devices are expected because they can change the color (from transparent to the colored condition) and the refraction index optically and the conductive property (from insulating to conductive) electrically.
However they are not yet practical because the reliability is still low and the usage environment is limited when a solution system electrolyte is used as the electrolyte 92 for the EC device 9 shown in
The coloring phenomenon occurs by the following two processes.
The rate controlling factors for the coloring process are the proton mobility in the electrolyte 92 in case of the drifting of (1) and the oxidization reaction rate of the water molecules by the holes h+ and the diffusion coefficient of the protons (H+) in case of the diffusion of (2).
However the reaction by the drifting of (1) is slow, and the reaction by the diffusion of (2) is also slow, an EC device using a solid-state system electrolyte as well as an EC device using a solution system electrolyte is not yet put into practical use.
Japanese Laid-open Patent Application (Tokkai-Syo 57-73749) discloses a technique for positioning an insulator film between the WO3 thin film 91 and the electrolyte 92. This technique improves the holding time of coloring, and the holding time can be from several minutes to a few months by an insulator film with 5-200 nm thickness. However this technique cannot achieve the high seed coloring and it is not practical.
The present invention was made to resolve the aforementioned problems, and the purpose of the present invention is to provide a reversible coloring and decoloring solid-state device, a reversible conductive property changing solid-state device, a reversible refractive index changing solid-state device, and the applications of these solid-state devices, e.g. a nonradiative display device, a conducting path device and a light waveguide device, which can dramatically improve the reversible changing characteristics (especially, the speed performance) of the optical and electric properties and the reliability while the electrolyte for supplying ions to the WO3 film is formed by a solid-state system.
(1) A reversible coloring and deccoloring solid-state device comprising a solid-state electrolyte film and a coloring and decoloring film which colors or decolors the coloring and decoloring film reversibly by applying an electric field, wherein
a barrier thin film being inserted between the solid-state electrolyte film and the coloring and decoloring film, the barrier thin film comprises at least one layer which is formed by a material having a band gap energy,
the barrier thin film has a thickness of the range between 7 nm and 7±2 nm,
the device is driven by a voltage (for example, 3V) so that the coloring speed is from 0.1 seconds to 0.3 seconds.
When the band gap energy of the barrier thin film is larger than the band gap energy of the coloring and decoloring film, the coloring speed becomes faster, and when the band gap energy of the barrier thin film is smaller than the band gap energy of the coloring and decoloring film, the coloring speed becomes slower. When the band gap energy of the barrier thin film is larger than the band gap energy of the solid-state electrolyte film, the coloring speed becomes faster, and when the band gap energy of the barrier thin film is smaller than the band gap energy of the solid-state electrolyte film, the coloring speed becomes slower.
(2) A reversible coloring and deccoloring solid-state device according to (1), wherein the band gap energy of the barrier thin film is larger than the band gap energy of the material of any of the films.
(3) A reversible coloring and deccoloring solid-state device comprising a solid-state electrolyte film and a coloring and decoloring film which colors the coloring and decoloring film by irradiating a light and decolors the colored coloring and decoloring film reversibly, wherein
a barrier thin film being inserted between the solid-state electrolyte film and the coloring and decoloring film, the barrier thin film comprises at least one layer which is formed by a material having a band gap energy,
the barrier thin film has a thickness of the range between 7 nm and 7±2 nm,
the device is driven by a voltage (for example, 3V) so that the coloring speed is from 0.1 seconds to 0.3 seconds.
When the band gap energy of the barrier thin film is larger than the band gap energy of the coloring and decoloring film, the coloring speed becomes faster, and when the band gap energy of the barrier thin film is smaller than the band gap energy of the coloring and decoloring film, the coloring speed becomes slower. When the band gap energy of the barrier thin film is larger than the band gap energy of the solid-state electrolyte film, the coloring speed becomes faster, and when the band gap energy of the barrier thin film is smaller than the band gap energy of the solid-state electrolyte film, the coloring speed becomes slower.
(4) A reversible coloring and deccoloring solid-state device according to (3), wherein the band gap energy of the barrier thin film is larger than the band gap energy of the material of any of the films.
(5) A reversible coloring and deccoloring solid-state device comprising a solid-sate electrolyte film and a color changing film, and changing the colored condition of the color changing film reversibly by applying an electric field, wherein
a barrier thin film being inserted between the solid-state electrolyte film and the color changing, the barrier thin film comprises at least one layer which is formed by a material having a band gap energy,
the barrier thin film has a thickness of the range between 7 nm and 7±2 nm,
the device is driven by a voltage (for example, 3V) so that the coloring speed is from 0.1 seconds to 0.3 seconds.
When the band gap energy of the barrier thin film is larger than the band gap energy of the color changing film, the coloring speed becomes faster, and when the band gap energy of the barrier thin film is smaller than the band gap energy of the color changing film, the coloring speed becomes slower. When the band gap energy of the barrier thin film is larger than the band gap energy of the solid-state electrolyte film, the coloring speed becomes faster, and when the band gap energy of the barrier thin film is smaller than the band gap energy of the solid-state electrolyte film, the coloring speed becomes slower.
(6) A reversible coloring and deccoloring solid-state device according to (5),
wherein the band gap energy of the barrier thin film is larger than the band gap energy of the material of any of the films.
(7) A reversible coloring and deccoloring solid-state device comprising a solid-sate electrolyte film and a color changing film, and changing the colored condition of the color changing film reversibly by irradiating a light and applying an electric field, wherein
a barrier thin film being inserted between the solid-state electrolyte film and the color changing film, the barrier thin film comprises at least one layer which is formed by a material having a band gap energy,
the barrier thin film has a thickness of the range between 7 nm and 7±2 nm,
the device is driven by a voltage (for example, 3V) so that the coloring speed is from 0.1 seconds to 0.3 seconds.
When the band gap energy of the barrier thin film is larger than the band gap energy of the color changing film, the coloring speed becomes faster, and when the band gap energy of the barrier thin film is smaller than the band gap energy of the color changing film, the coloring speed becomes slower. When the band gap energy of the barrier thin film is larger than the band gap energy of the solid-state electrolyte film, the coloring speed becomes faster, and when the band gap energy of the barrier thin film is smaller than the band gap energy of the solid-state electrolyte film, the coloring speed becomes slower.
(8) A reversible coloring and deccoloring solid-state device according to (7), wherein the band gap energy of the barrier thin film is larger than the band gap energy of the material of any of the films.
(9) A reversible conductive property changing solid-state device comprising a solid-sate electrolyte film and a conductive property changing film, and making the conductive property changing film conductive or insulating reversibly by applying an electric field, wherein
a barrier thin film being inserted between the solid-state electrolyte film and the conductive property changing film, the barrier thin film comprises at least one layer which is formed by a material having a band gap energy,
the barrier thin film has a thickness of the range between 7 nm and 7±2 nm,
the device is driven in the direction that the conductivity becomes higher by a voltage (for example, 3V) so that the conductive property changing speed is from 0.1 seconds to 0.3 seconds.
When the band gap energy of the barrier thin film is larger than the band gap energy of the conductive property changing film, the conductive property change (change from a low conductive property to a high conductive property) becomes faster, and when the band gap energy of the barrier thin film is smaller than the band gap energy of the conductive property changing film, the conductive property change becomes slower. When the band gap energy of the barrier thin film is larger than the band gap energy of the solid-state electrolyte film, the conductive property change (change from a high conductive property to a low conductive property) becomes faster, and when the band gap energy of the barrier thin film is smaller than the band gap energy of the solid-state electrolyte film, the conductive property change becomes slower.
(10) A reversible conductive property changing solid-state device according to (9), wherein the band gap energy of the barrier thin film is larger than the band gap energy of the material of any of the films.
(11) A reversible conductive property changing solid-state device comprising a solid-sate electrolyte film and a conductive property changing film, and making the conductive property changing film conductive by irradiating a light and making the conductive property changing film insulating by applying an electric field reversibly, wherein
a barrier thin film being inserted between the solid-state electrolyte film and the conductive property changing film, the barrier thin film comprises at least one layer which is formed by a material having a band gap energy,
the barrier thin film has a thickness of the range between 7 nm and 7±2 nm,
the device is driven in the direction that the conductive property increases by a voltage (for example, 3V) so that the conductive property changing speed is from 0.1 seconds to 0.3 seconds.
When the band gap energy of the barrier thin film is larger than the band gap energy of the conductive property changing film, the conductive property change (change from a low conductive property to a high conductive property) becomes faster, and when the band gap energy of the barrier thin film is smaller than the band gap energy of the conductive property changing film, the conductive property change becomes slower. When the band gap energy of the barrier thin film is larger than the band gap energy of the solid-state electrolyte film, the conductive property change (change from a high conductive property to a low conductive property) becomes faster, and when the band gap energy of the barrier thin film is smaller than the band gap energy of the solid-state electrolyte film, the conductive property change becomes slower.
(12) A reversible conductive property changing solid-state device according to (11), wherein the band gap energy of the barrier thin film is larger than the band gap energy of the material of any of the films.
(13) A reversible conductive property changing solid-state device comprising a solid-sate electrolyte film and a conductive property changing film, and changing the conductive property of the conductive property changing film by applying an electric field reversibly, wherein
a barrier thin film being inserted between the solid-state electrolyte film and the conductive property changing film, the barrier thin film comprises at least one layer which is formed by a material having a band gap energy,
the barrier thin film has a thickness of the range between 7 nm and 7±2 nm,
the device is driven in the direction that the conductive property increases by a voltage (for example, 3V) so that the conductive property changing speed is from 0.1 seconds to 0.3 seconds.
When the band gap energy of the barrier thin film is larger than the band gap energy of the conductive property changing film, the conductive property change (change from a low conductive property to a high conductive property) becomes faster, and when the band gap energy of the barrier thin film is smaller than the band gap energy of the conductive property changing film, the conductive property change becomes slower. When the band gap energy of the barrier thin film is larger than the band gap energy of the solid-state electrolyte film, the conductive property change (change from a high conductive property to a low conductive property) becomes faster, and when the band gap energy of the barrier thin film is smaller than the band gap energy of the solid-state electrolyte film, the conductive property change becomes slower.
(14) A reversible conductive property changing solid-state device according to (13), wherein the band gap energy of the barrier thin film is larger than the band gap energy of the material of any of the films.
(15) A reversible conductive property changing solid-state device comprising a solid-sate electrolyte film and a conductive property changing film, and reversibly changing the conductive property of the conductive property changing film by applying an electric field and irradiating a light, wherein
a barrier thin film being inserted between the solid-state electrolyte film and the conductive property changing film, the barrier thin film comprises at least one layer which is formed by a material having a band gap energy,
the barrier thin film has a thickness of the range between 7 nm and 7±2 nm,
the device is driven in the direction that the conductive property increases by a voltage (for example, 3V) so that the conductive property changing speed is from 0.1 seconds to 0.3 seconds.
When the band gap energy of the barrier thin film is larger than the band gap energy of the conductive property changing film, the conductive property change (change from a low conductive property to a high conductive property) becomes faster, and when the band gap energy of the barrier thin film is smaller than the band gap energy of the conductive property changing film, the conductive property change becomes slower. When the band gap energy of the barrier thin film is larger than the band gap energy of the solid-state electrolyte film, the conductive property change (change from a high conductive property to a low conductive property) becomes faster, and when the band gap energy of the barrier thin film is smaller than the band gap energy of the solid-state electrolyte film, the conductive property change becomes slower.
(16) A reversible conductive property changing solid-state device according to (15), wherein the band gap energy of the barrier thin film is larger than the band gap energy of the material of any of the films.
(17) A reversible refractive index changing solid-state device comprising a solid-sate electrolyte film and a refractive index changing film, and reversibly changing the refractive index of the refractive index changing film from a first refractive index to a second refractive index or from the second refractive index to the first refractive index reciprocally by applying an electric field, wherein
a barrier thin film being inserted between the solid-state electrolyte film and the refractive index changing film, the barrier thin film comprises at least one layer which is formed by a material having a band gap energy,
the barrier thin film has a thickness of the range between 7 nm and 7±2 nm,
the device is driven in the direction that the refractive index increases by a voltage (for example, 3V) so that the refractive index changing speed is from 0.1 seconds to 0.3 seconds.
When the band gap energy of the barrier thin film is larger than the band gap energy of the refractive index changing film, the refractive index change (change from a low refractive index to a high refractive index) becomes faster, and when the band gap energy of the barrier thin film is smaller than the band gap energy of the refractive index changing film, the refractive index change becomes slower. When the band gap energy of the barrier thin film is larger than the band gap energy of the solid-state electrolyte film, the refractive index change (change from a high refractive index to a low refractive index) becomes faster, and when the band gap energy of the barrier thin film is smaller than the band gap energy of the solid-state electrolyte film, the refractive index change becomes slower.
(18) A reversible refractive index changing solid-state device according to (17), wherein the band gap energy of the barrier thin film is larger than the band gap energy of the material of any of the films.
(19) A reversible refractive index changing solid-state device comprising a solid-sate electrolyte film and a refractive index changing film, and reversibly changing the refractive index of the refractive index changing film by irradiating a light and putting the refractive index of the refractive index changed refractive index changing film back to the original refractive index by applying an electric field, wherein
a barrier thin film being inserted between the solid-state electrolyte film and the refractive index changing film, the barrier thin film comprises at least one layer which is formed by a material having a band gap energy,
the barrier thin film has a thickness of the range between 7 nm and 7±2 nm,
the device is driven in the direction that the refractive index increases by a voltage (for example, 3V) so that the refractive index changing speed is from 0.1 seconds to 0.3 seconds.
When the band gap energy of the barrier thin film is larger than the band gap energy of the refractive index changing film, the refractive index change (change from a low refractive index to a high refractive index) becomes faster, and when the band gap energy of the barrier thin film is smaller than the band gap energy of the refractive index changing film, the refractive index change becomes slower. When the band gap energy of the barrier thin film is larger than the band gap energy of the solid-state electrolyte film, the refractive index change (change from a high refractive index to a low refractive index) becomes faster, and when the band gap energy of the barrier thin film is smaller than the band gap energy of the solid-state electrolyte film, the refractive index change becomes slower.
(20) A reversible refractive index changing solid-state device according to (19), wherein the band gap energy of the barrier thin film is larger than the band gap energy of the material of any of the films.
(21) A reversible refractive index changing solid-state device comprising a solid-sate electrolyte film and a refractive index changing film, and reversibly changing the refractive index of the refractive index changing film by applying an electric field, wherein
a barrier thin film being inserted between the solid-state electrolyte film and the refractive index changing film, the barrier thin film comprises at least one layer which is formed by a material having a band gap energy,
the barrier thin film has a thickness of the range between 7 nm and 7±2 nm,
the device is driven in the direction that the refractive index increases by a voltage (for example, 3V) so that the refractive index changing speed is from 0.1 seconds to 0.3 seconds.
When the band gap energy of the barrier thin film is larger than the band gap energy of the refractive index changing film, the refractive index change (change from a low refractive index to a high refractive index) becomes faster, and when the band gap energy of the barrier thin film is smaller than the band gap energy of the refractive index changing film, the refractive index change becomes slower. When the band gap energy of the barrier thin film is larger than the band gap energy of the solid-state electrolyte film, the refractive index change (change from a high refractive index to a low refractive index) becomes faster, and when the band gap energy of the barrier thin film is smaller than the band gap energy of the solid-state electrolyte film, the refractive index change becomes slower.
(22) A reversible refractive index changing solid-state device according to (21), wherein the band gap energy of the barrier thin film is larger than the band gap energy of the material of any of the films.
(23) A reversible refractive index changing solid-state device comprising a solid-sate electrolyte film and a refractive index changing film, and reversibly changing the refractive index of the refractive index changing film by irradiating a light and applying an electric field, wherein
a barrier thin film being inserted between the solid-state electrolyte film and the refractive index changing film, the barrier thin film comprises at least one layer which is formed by a material having a band gap energy,
the barrier thin film has a thickness of the range between 7 nm and 7±2 nm,
the device is driven in the direction that the refractive index increases by a voltage (for example, 3V) so that the refractive index changing speed is from 0.1 seconds to 0.3 seconds.
When the band gap energy of the barrier thin film is larger than the band gap energy of the refractive index changing film, the refractive index change (change from a low refractive index to a high refractive index) becomes faster, and when the band gap energy of the barrier thin film is smaller than the band gap energy of the refractive index changing film, the refractive index change becomes slower. When the band gap energy of the barrier thin film is larger than the band gap energy of the solid-state electrolyte film, the refractive index change (change from a high refractive index to a low refractive index) becomes faster, and when the band gap energy of the barrier thin film is smaller than the band gap energy of the solid-state electrolyte film, the refractive index change becomes slower.
(24) A reversible refractive index changing solid-state device according to (23), wherein the band gap energy of the barrier thin film is larger than the band gap energy of the material of any of the films.
(25) A nonradiative display device, wherein the reversible coloring and decoloring solid-state device according to either one of (1) to (8) is formed on a semiconductor substrate, a glass substrate or a plastic substrate as an array, the reversible coloring and decoloring solid-state device or a group of the coloring and decoloring solid-state devices is used as one pixel. The nonradiative display device can be configured as a back light display or a reflective display.
(26) A conducting path device, wherein the reversible conductive property changing solid-state device according to (9), (10), (13) or (14) is formed on a semiconductor substrate, a glass substrate or a plastic substrate in an arbitrary pattern,
the conductive property of the conductive property changing film is controlled by applying an electric field.
(27) A conducting path device, wherein the reversible conductive property changing solid-state device according to (11), (12), (15) or (16) is formed on a semiconductor substrate, a glass substrate or a plastic substrate in an arbitrary pattern,
the conductive property of the conductive property changing film is controlled by irradiating a light and applying an electric field.
(28) A light waveguide device, wherein the reversible refractive index changing solid-state device according to (17), (18), (21) or (22) is formed on a semiconductor substrate, a glass substrate or a plastic substrate in an arbitrary pattern,
the refractive index changing film is formed as a core layer of the light waveguide and the refractive index of the refractive index changing film is controlled by applying an electric field.
(29) A light waveguide device, wherein the reversible refractive index changing solid-state device according to (19), (20), (23) or (24) is formed on a semiconductor substrate, a glass substrate or a plastic substrate in an arbitrary pattern,
the refractive index changing film is formed as a core layer of the light waveguide and the refractive index of the refractive index changing film is controlled by irradiating a light and applying an electric field.
According to the present invention, the following methods can be implemented.
(A1) A method for coloring and decoloring a reversible coloring and decoloring solid-state device comprising a solid-state electrolyte film and a coloring and decoloring film, which colors or decolors the coloring and decoloring solid-state device reversibly by applying an electric field, wherein
a barrier thin film is inserted between the solid-state electrolyte film and the coloring and decoloring film, the barrier thin film comprises at least one layer which is formed by a material having a band gap energy, has a thickness of 7 nm to 7±2 nm, does not prevent ion conduction, and prevents carrier movement,
the coloring and decoloring speed is 0.1 seconds to 0.3 seconds by a voltage driving.
(A2) A method for coloring and decoloring a reversible coloring and decoloring solid-state device comprising a solid-state electrolyte film and a color changing film, which colors or decolors the coloring and decoloring solid-state device reversibly by irradiating a light, wherein
a barrier thin film is inserted between the solid-state electrolyte film and the coloring and decoloring film, the barrier thin film comprises at least one layer which is formed by a material having a band gap energy, has a thickness of 7 nm to 7±2 nm, does not prevent ion conduction, and prevents carrier movement,
the coloring and decoloring speed is 0.1 seconds to 0.3 seconds by a voltage driving.
(A3) A method for changing the color of a reversible color changing solid-state device comprising a solid-state electrolyte film and a color changing film, which reversibly changes the colored condition of the color changing film by applying an electric field, wherein
a barrier thin film is inserted between the solid-state electrolyte film and the color changing film, the barrier thin film comprises at least one layer which is formed by a material having a band gap energy, has a thickness of 7 nm to 7±2 nm, does not prevent ion conduction, and prevents carrier movement,
the color changing speed is 0.1 seconds to 0.3 seconds by a voltage driving.
(A4) A method for changing the color of a reversible color changing solid-state device comprising a solid-state electrolyte film and a color changing film, which reversibly changes the colored condition of the color changing film by irradiating a light and applying an electric field, wherein
a barrier thin film is inserted between the solid-state electrolyte film and the color changing film, the barrier thin film comprises at least one layer which is formed by a material having a band gap energy, has a thickness of 7 nm to 7±2 nm, does not prevent ion conduction, and prevents carrier movement,
the conductive property changing speed is 0.1 seconds to 0.3 seconds by a voltage driving.
(A5) A method for changing the conductive property of a reversible conductive property changing solid-state device comprising a solid-state electrolyte film and a conductive property changing film, which reversibly makes the conductive property changing film conductive or insulating by applying an electric field, wherein
a barrier thin film is inserted between the solid-state electrolyte film and the conductive property changing film, the barrier thin film comprises at least one layer which is formed by a material having a band gap energy, functions as a movement barrier for carriers, has a thickness of 7 nm to 7±2 nm,
the conducive property changing speed is 0.1 seconds to 0.3 seconds by a voltage driving.
(A6) A method for changing the conductive property of a reversible conductive property changing solid-state device comprising a solid-state electrolyte film and a conductive property changing film, which reversibly makes the conductive property changing film conductive by irradiating a light and makes the conducting conductive property changing film insulating by applying an electric field, wherein
a barrier thin film is inserted between the solid-state electrolyte film and the conductive property changing film, the barrier thin film comprises at least one layer which is formed by a material having a band gap energy, functions as a movement barrier for carriers, has a thickness of 7 nm to 7±2 nm,
the conducive property changing speed is 0.1 seconds to 0.3 seconds by a voltage driving.
The basic structure and operation of a reversible coloring and decoloring solid-state device, a reversible conductive property changing solid-state device and a reversible refractive index changing solid-state device according to the present invention will be explained referring to
In
According to the present invention, the coloring is driven at a voltage which provides a coloring speed from 0.1 seconds to 0.3 seconds. Specifically, the voltage at the time of coloring can be 3V.
The holes h+ are accumulated and its density becomes high on the boundary face between the solid-state electrolyte film 12 and the barrier thin film 13 and the generation density of H+ by oxidization reaction. As a result of this operation, the coloring speed improves significantly.
As a result of a detail study, the inventors found that when the thickness of the SiO2 thin film is from 7 nm to 7±2 nm, the coloring speed becomes significantly high because the accumulated holes h+contribute to the generation of the protons (H+) by priority, while the proton moves to WO3 relatively easily by ion movement.
As the barrier by the barrier thin film 13 prevents the diffusion of electrons e− to the side of the solid-state electrolyte film 12 and inhibits the diffusion of holes h+ to the side of the coloring and decoloring film 11, natural decoloring is inhibited, and therefore the maintenance performance of the color is improved.
That is to say, the diffusion of electrons to the side of the solid-state electrolyte and the diffusion of holes to the side of the WO3 is inhibited at the same time by the barrier effect of SiO2, therefore the decoloring by the backward reaction of the coloring is inhibited.
HxWO3→xH++xe−+WO3
The EC device 1 can be colored by light excitation.
As shown in the energy band chart of
On the other hand, in the colored condition, when a reverse bias voltage Vb′ is applied in the direction that the acting electrode 141 is the positive electrode and the opposing electrode 142 is the negative electrode, the barrier thin film 13 becomes a great barrier for the electrons e− as shown in
Although the material of the thin film 13 is formed form a material having a band gap energy which is larger than that of any material of the coloring and decoloring film 11 and the solid-sate electrolyte film 12 in this embodiment, other materials having an appropriate band gap energy can be selected depending on the purpose (whether faster or slower changing speed, etc.). The thickness of the thin film 13 is also adjusted depending on the material.
The barrier thin film 13 is formed by multiple layers (layers comprising the same compound or different kind of compounds). For example, it is formed by two SiO2 layers having different properties. By this structure, the coloring and decoloring speed, the conductive property changing speed and the refractive index changing speed.
According to the present invention, as the coloring and decoloring film 11 or the conductive property changing film and the refractive index changing film, it is possible to use WO3, an oxide of transition metal element M (for example, MoO3, IrO2, TiO2, Nb2O5, V2O5, Rh2O3), a hydroxide (for example, NiOOH, CoOOH), a compound of M and chalcogen element X (S, Se, Te), i.e. MX, M2X3, MX2, MX3, MX5, and their complex compound (for example, SrTiO3, CaTiO3), a perovskite structure material, a material which belongs to a intercalation compound, their mixed material, a nitride, e.g. In, Sn, an organic material, e.g. a diphthalocyanine complex, a heptylviologen.
According to the present invention, as the solid-state electrolyte film 12, it is possible to use Ta2O5, an oxide, e.g. Cr2O3, high ion conductive CaF2, AgI, β alumina, and ion conducting polymer molecule.
According to the present invention, as the barrier thin film 13, it is possible to use SiO2, LiOx, LiNx, NaOx, KOx, RbOx, CsOx, BeOx, MgOx, MgNx, CaOx, CaNx, Srx, aOx, ScOx, YOx, YNx, LaOx, LaNx, CeOx, PrOx, NdOx, SmOx, EuOx, GdOx, TbOx, DyOx, HoOx, ErOx, TmOx, YbOx, LuOx, TiOx, TiNx, ZrOx, ZrNx, HfOx, HfNx, ThOx, VOx, VNx, NbOx, NbNx, TaOx, TaNx, CrOx, CrNx, MoOx, MoN, WOx, WNx, MnOx.
One embodiment of a reversible coloring and decoloring solid-state device (EC device) according to the present invention will be explained referring to
WO3 is deposited as the coloring and decoloring film 23 by the RF sputtering method, and SiO2 is deposited as the barrier thin film 24 using the RF sputtering method.
Ta2O5 (source of supplying hydrogen ions H+) is deposited as the solid-state electrolyte film 25 by the EB vapor deposition. Although oxide tantalum Ta2O5 is dielectric, since a slight amount of water molecules absorbed in the film generate hydrogen ions, oxide tantalum Ta2O5 functions as a solid-state electrolyte.
The film forming condition for the coloring and decoloring film 23 (WO3 film) is:
Substrate temperature: room temperature
Sputtering atmosphere: Ar/O2 mixed gas (ratio 1:1)
Supplied power: 50 W
Degree of vacuum during film formation: 15 mTorr,
and 300 nm WO3 film was formed in this embodiment.
The film forming condition for the barrier thin film 24 (SiO2 film) is:
Substrate temperature: room temperature
Sputtering atmosphere: Ar/O2 mixed gas (ratio 1:1)
Supplied power: 50 W
Degree of vacuum during film formation: 15 mTorr,
and 7 nm SiO2 film was formed in this embodiment.
The film forming condition for the solid-state electrolyte film 25 (Ta2O5 film) is:
Substrate temperature: 60° C. or lower
Evaporation speed: 0.07 nm/s
and 400 nm Ta2O5 film was formed in this embodiment.
The band gap energy (Eg) is 3.2 eV for WO3, 4.25 eV for Ta2O5 and 6-8 eV for SiO2 (it depends on the film quality, high for a single crystal and low for an amorphous condition),
The barrier inhibits the reverse reaction, or decoloring. By this operation, the speed of coloring to blue becomes significantly high by the generation of H×WO3. In this embodiment, a voltage which provides the coloring speed of 0.1 seconds to 0.3 seconds is used for coloring. Specifically, the voltage of 3V is applied to the reversible coloring and decoloring solid-state device 2 by the polarity shown in
As shown in
One embodiment of a reversible coloring and decoloring solid-state device by light excitation according to the present invention will be explained referring to
WO3 is deposited as the coloring and decoloring film 32 by the RF sputtering method, and a SiO2 thin film is deposited as the barrier thin film 33 using the RF sputtering method. Ta2O5 is deposited as the solid-state electrolyte film 34 by the EB vapor deposition.
The film forming condition for the coloring and decoloring film 32 (WO3 film) is:
Substrate temperature: room temperature
Sputtering atmosphere: Ar/O2 mixed gas (ratio 1:1)
Supplied power: 50 W
Degree of vacuum during film formation: 15 mTorr,
and 300 nm WO3 film was formed in this embodiment.
The film forming condition for the barrier thin film 33 (SiO2 film) is:
Substrate temperature: room temperature
Sputtering atmosphere: Ar/O2 mixed gas (ratio 1:1)
Supplied power: 50 W
Degree of vacuum during film formation: 15 mTorr,
and 7 nm SiO2 film was formed in this embodiment.
The film forming condition for the solid-state electrolyte film 34 (Ta2O5 film) is:
Substrate temperature: 60° C. or lower
Evaporation speed: 0.07 nm/s
and 400 nm Ta2O5 film was formed in this embodiment.
The band gap energy (Eg) is 3.2 eV for WO3, 4.25 eV for Ta2O5 and 6-8 eV for SiO2.
Xe lamp light is irradiated to this device and the measurement result of the time dependency of the coloring by changing the transmission of the incoming light is shown in
As shown in
One embodiment of a conducting path device (a switching device (a reversible conductive property changing solid-state device)) according to the present invention will be explained referring to
WO3 is deposited as the conductive property changing film 43 by the RF sputtering method, and a SiO2 thin film is deposited as the barrier thin film 44 using the RF sputtering method. Ta2O5 (source of supplying hydrogen ions H+) is deposited as the solid-state electrolyte film 45 by the EB vapor deposition.
The film forming condition for the conductive property changing film 43 (WO3 film) is:
Substrate temperature: room temperature
Sputtering atmosphere: Ar/O2 mixed gas (ratio 1:1)
Supplied power: 50 W
Degree of vacuum during film formation: 15 mTorr,
and 300 nm WO3 film was formed in this embodiment.
The film forming condition for the barrier thin film 44 (SiO2 film) is:
Substrate temperature: room temperature
Sputtering atmosphere: Ar/O2 mixed gas (ratio 1:1)
Supplied power: 50 W
Degree of vacuum during film formation: 15 mTorr,
and 7 nm SiO2 film was formed in this embodiment.
The film forming condition for the solid-state electrolyte film 45 (Ta2O5 film) is:
Substrate temperature: 60° C. or lower
Evaporation speed: 0.07 nm/s
and 400 nm Ta2O5 film was formed in this embodiment.
Al electrodes b1, b2 are deposited to the thickness of 300 nm by a vapor deposition method and they are buried in the conductive property changing film 43 (WO3 film). The voltage of 3V is applied to the conducting path device 4 by the polarity shown in
As shown in
One embodiment of a reversible refractive index changing solid-state device according to the present invention will be explained referring to
WO3 is deposited as the refractive index changing film 53 by the RF sputtering method, and a SiO2 thin film is deposited as the barrier thin film 54 using the RF sputtering method. Ta2O5 (source of supplying hydrogen ions H+) is deposited as the solid-state electrolyte film 55 by the EB vapor deposition.
The film forming condition for the refractive index changing film 53 (WO3 film) is:
Substrate temperature: room temperature
Sputtering atmosphere: Ar/O2 mixed gas (ratio 1:1)
Supplied power: 50 W
Degree of vacuum during film formation: 15 mTorr,
and 300 nm WO3 film was formed in this embodiment.
The film forming condition for the barrier thin film 54 (SiO2 film) is:
Substrate temperature: room temperature
Sputtering atmosphere: Ar/O2 mixed gas (ratio 1:1)
Supplied power: 50 W
Degree of vacuum during film formation: 15 mTorr,
and 7 nm SiO2 film was formed in this embodiment.
The film forming condition for the solid-state electrolyte film 55 (Ta2O5 film) is:
Substrate temperature: 60° C. or lower
Evaporation speed: 0.07 nm/s
and 400 nm Ta2O5 film was formed in this embodiment.
The voltage of 3V is applied to the refractive index changing solid-state device 5 by the polarity shown in
As shown in
One embodiment of a light waveguide device (a light switching device) according to the present invention will be explained referring to
The film forming condition for the refractive index changing film 63 (WO3 film) is:
Substrate temperature: room temperature
Sputtering atmosphere: Ar/O2 mixed gas (ratio 1:1)
Supplied power: 50 W
Degree of vacuum during film formation: 15 mTorr,
A film of 2 μm thickness was formed in this embodiment.
The film forming condition for the barrier thin film 44 (SiO2 film) is:
Substrate temperature: room temperature
Sputtering atmosphere: Ar/O2 mixed gas (ratio 1:1)
Supplied power: 50 W
Degree of vacuum during film formation: 15 mTorr,
A film of about 7 nm thickness was formed in this embodiment.
The film forming condition for the solid-state electrolyte film 45 (Ta2O5 film) is:
Substrate temperature: 60° C. or lower
Evaporation speed: 0.07 nm/s
A film of about 3 μm thickness was formed in this embodiment.
Since the refractive index of Ta2O5 (2.1) is smaller than that of WO3 (2.8), the refractive index changing film 63 (WO3 film) functions as the core layer of a light waveguide, and the solid-state electrolyte film 65 (Ta2O5 film) functions as the cladding layer. Therefore, when the He—Ne laser light (h ν) which was condensed by a lens is irradiated on one end face of the light waveguide device 6, the light propagates in the refractive index changing film 63 and exits from the opposing end face. That is to say, the light waveguide device 6 is in ON state of a light switch (See
When a forward bias voltage of 3V is applied between the acting electrode 62 and the opposing electrode 66 so that the acting electrode 42 becomes the negative electrode and the opposing electrode 46 becomes the positive electrode, the refractive index changing film 63 (WO3 film) is colored and the transmission factor of the incoming light becomes low. By this operation, the light is substantially is blocked and the light waveguide device 6 enters in OFF state of a light switch (See
In this embodiment, a voltage which provides the refraction index changing speed of 0.1 seconds to 0.3 seconds is used. Specifically, the voltage of 3V is applied to the light waveguide device 6 by the polarity shown in
The refractive index of the refractive index changing film 63 can be controlled by the aforementioned application of an electric field. The light waveguide device 6 can be formed on the glass substrate 61 in an arbitrary pattern. The light waveguide device 6 can also be formed on a semiconductor substrate or a plastic substrate in an arbitrary pattern
One embodiment of a nonradiative display device according to the present invention will be explained referring to
In this embodiment, a polyimide film is used as the plastic substrate 71, porous Al2O3 is deposited on the plastic substrate 71 as the white background thin film 72, and a transparent electrode (ITO thin film) is deposited on the white background thin film 72 as the acting electrode 73. Next, WO3 is deposited by RF sputtering as the coloring and decoloring film 74, and a thin line pattern of WO3 is formed by removing the mask. Then, SiO2 is deposited by RF sputtering as the barrier thin film 75, and Ta2O5 is deposited by EB vapor deposition as the solid-state electrolyte film 76.
The film forming condition for the coloring and decoloring film 74 (WO3 film) is:
Substrate temperature: room temperature
Sputtering atmosphere: Ar/O2 mixed gas (ratio 1:1)
Supplied power: 50 W
Degree of vacuum during film formation: 15 mTorr,
300 nm WO3 film was formed in this embodiment.
The film forming condition for the barrier thin film 75 (SiO2 film) is:
Substrate temperature: room temperature
Sputtering atmosphere: Ar/O2 mixed gas (ratio 1:1)
Supplied power: 50 W
Degree of vacuum during film formation: 15 mTorr,
7 nm SiO2 film was formed in this embodiment.
The film forming condition for the solid-state electrolyte film 76 (Ta2O5 film) is:
Substrate temperature: 60° C. or lower
Evaporation speed: 0.07 nm/s
400 nm Ta2O5 film was formed in this embodiment.
A transparent electrode ITO thin film is used for the acting electrode 77, and the stripes of the contact portion for electric input and the segments of the display portion are formed in a pattern. In this embodiment, a voltage which provides the coloring speed of 0.1 seconds to 0.3 seconds is used for coloring. Specifically, the voltage of 3V is applied to the nonradiative display device 7 by the polarity shown in
It is confirmed that a numeric characters can be displayed by a dark blue font on the white background by selecting the corresponding 7 segments and controlling the address signal in the direction that a voltage is applied for the electrode on the substrate side. The nonradiative display device 8 operates at a low voltage and has a enough high contrast and response speed for a display. Since the substrate is quite flexible and all elements are configured by the solid-state thin film, this device can be used as a paper like display of a super thin thickness and light weight.
By inserting a thin film barrier layer between the coloring and decoloring film and the ion supplying thin film, the coloring efficiency and response speed is significantly improved while the all configurations of the EC device is formed by solid-state thin films.
While the invention has been explained with reference to the specific embodiments of the invention, the explanation is illustrative and the invention is limited only by the appended claims.
Number | Date | Country | Kind |
---|---|---|---|
2005-118885 | Mar 2005 | JP | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/JP2006/306065 | 3/20/2006 | WO | 00 | 1/17/2008 |