WO2021095403A1 - Method for controlling work function of electrode, power generation element, and method for producing power generation element - Google Patents

Method for controlling work function of electrode, power generation element, and method for producing power generation element Download PDF

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Publication number
WO2021095403A1
WO2021095403A1 PCT/JP2020/037950 JP2020037950W WO2021095403A1 WO 2021095403 A1 WO2021095403 A1 WO 2021095403A1 JP 2020037950 W JP2020037950 W JP 2020037950W WO 2021095403 A1 WO2021095403 A1 WO 2021095403A1
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electrode
work function
oxide film
power generation
annealing
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PCT/JP2020/037950
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French (fr)
Japanese (ja)
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後藤　博史
坂田　稔
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株式会社Ｇｃｅインスティチュート
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02N—ELECTRIC MACHINES NOT OTHERWISE PROVIDED FOR
    • H02N11/00—Generators or motors not provided for elsewhere; Alleged perpetua mobilia obtained by electric or magnetic means
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N15/00—Thermoelectric devices without a junction of dissimilar materials; Thermomagnetic devices, e.g. using the Nernst-Ettingshausen effect

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  • An embodiment of the present invention relates to a method of controlling a work function of electrodes, a power generation element, and a method of manufacturing a power generation element.
  • Patent Documents 1 and 2 disclose thermoelectric elements that utilize an electron emission phenomenon due to absolute temperature that occurs between electrodes having a work function difference. Such a thermoelectric element can generate electricity even when the temperature difference between the electrodes is small as compared with the thermoelectric element using the temperature difference between the electrodes (Seebeck effect). Therefore, it is expected to be used for various purposes.
  • thermoelectric element comprises the spherical nanobeads, the work function of the emitter electrode layer is smaller than the work function of the collector electrode layer, and the particle size of the spherical nanobeads is 100 nm or less.
  • Patent Document 2 includes a nanofluid having a high work function anode and a low work function cathode separated by nanometer-scale spaced electrode-to-electrode gaps, in which nanofluids are formed in the inter-electrode gaps. Contact potential difference cells are disclosed.
  • thermoelectric element (power generation element) disclosed in Patent Document 1 and the nanofluid contact potential difference cell (power generation element) disclosed in Patent Document 2 require two electrodes having different work functions, and two electrodes. Different conductive materials are used for each of the electrodes.
  • Patent Documents 1 and 2 in order to use different conductive substances, for example, the following circumstances occur. -It is necessary to purchase raw materials for different conductive substances. -It is necessary to prepare an expensive film forming apparatus or an expensive production line for each different conductive substance. Therefore, in Patent Documents 1 and 2, the manufacturing cost of the power generation element increases.
  • An embodiment of the present invention provides a method for controlling a work function of electrodes and a method for manufacturing a power generation element and a power generation element, which can suppress the manufacturing cost of the power generation element.
  • the method of controlling the work function of the electrode according to the first aspect of the present invention is a method of controlling the work function of the electrode of the power generation element that converts thermal energy into electrical energy, and the power generation element includes the first electrode and the first electrode.
  • Each of the first electrode and the second electrode is the same conductive material, the second electrode is annealed, and the value of the work function of the second electrode is set to the first electrode. It is characterized in that the value of the work function of the nanoparticle is changed beyond the value of the work function of the nanoparticles.
  • the method for controlling the work function of the electrode according to the second aspect of the present invention is that in the first aspect, the annealing is performed in an oxidizing atmosphere, and at least the surface of the second electrode facing the first electrode is oxidized. It is characterized by doing.
  • the first oxide film of the conductive substance is formed on at least the surface of the first electrode facing the second electrode.
  • the annealing is performed in an oxidizing atmosphere, and the annealing is performed by the annealing.
  • (1) Increase the oxidation number of the second oxide film from the oxidation number of the first oxide film
  • (2) Make the thickness of the second oxide film thicker than the thickness of the first oxide film.
  • Passivation of the second oxide film from the first oxide film is characterized by performing at least one of the above (1) to (3).
  • the method for controlling the work function of the electrode according to the fourth aspect of the present invention is characterized in that, in the third aspect, the oxidizing atmosphere is the atmosphere.
  • the method for controlling the work function of the electrode according to the fifth aspect of the present invention is that in the first aspect, the annealing is performed in a reducing atmosphere, and at least the surface of the second electrode facing the first electrode is reduced. It is characterized by doing.
  • the first oxide film of the conductive substance is formed on at least the surface of the first electrode facing the second electrode.
  • the annealing is performed in a reducing atmosphere, and the annealing is performed by the annealing.
  • (4) Decrease the oxidation number of the second oxide film from the oxidation number of the first oxide film (5) Make the thickness of the second oxide film thinner than the thickness of the first oxide film (5) 6) It is characterized in that at least one of the above (4) to (6) is performed to passivate the second oxide film from the first oxide film.
  • the method for controlling the work function of the electrode according to the seventh aspect of the present invention is that in any one of the third to sixth aspects, each of the first oxide film and the second oxide film before being annealed , It is a natural oxide film of the conductive substance.
  • the method for controlling the work function of the electrode according to the eighth aspect of the present invention is that in the first aspect, the annealing is performed under reduced pressure or in an inert atmosphere, and the second electrode is allotropically transformed from the first electrode. It is characterized by letting it.
  • the annealing is performed in an active atmosphere, and at least the surface of the second electrode facing the first electrode is surface-modified. It is characterized by quality.
  • the method for controlling the work function of the electrode according to the tenth aspect of the present invention is characterized in that, in any one of the first to ninth aspects, the conductive substance contains a Group 4 element.
  • the method for controlling the work function of the electrode according to the eleventh aspect of the present invention is that the first electrode is not annealed in any one of the first to tenth aspects, and the annealing temperature of the first electrode is the first. It is characterized in that it is lower than the two electrodes, the annealing time of the first electrode is shorter than that of the second electrode, or the annealing energy of the first electrode is lower than that of the second electrode.
  • the method for controlling the work function of the electrode according to the twelfth aspect of the present invention is any one of the first to eleventh aspects, wherein the annealing includes at least one of thermal annealing, laser annealing and optical annealing. It is characterized by.
  • the power generation element includes a first electrode, a second electrode facing the first electrode via a gap, a work function of the first electrode provided in the gap, and the first electrode. It has an intermediate portion containing nanoparticles having a work function between the two electrodes, and each of the first electrode and the second electrode is the same conductive material, and the second electrode has. At least the state of the surface facing the first electrode is different from the state of the surface of the first electrode facing at least the second electrode.
  • the power generation element according to the 14th aspect of the present invention is characterized in that, in the 13th aspect, at least the surface of the second electrode facing the first electrode is oxidized.
  • the power generation element according to the fifteenth aspect of the present invention is characterized in that, in the thirteenth aspect, at least the surface of the second electrode facing the first electrode is reduced.
  • the power generation element has a first oxide film of the conductive substance on at least the surface of the first electrode facing the second electrode, and the second electrode. At least on the surface of the electrode facing the first electrode, there is a second oxide film of the conductive substance, and the second oxide film is formed on the second oxide film.
  • the oxidation number of the second oxide film is larger than the oxidation number of the first oxide film.
  • the thickness of the second oxide film is thicker than the thickness of the first oxide film (9).
  • the second oxide film is characterized by taking at least one of the states described in (7) to (9) above, which contains a homogenous variant of the first oxide film.
  • the power generation element according to the 17th aspect of the present invention is characterized in that, in the 13th aspect, the second electrode contains an allotropic transformation of the first electrode.
  • the power generation element according to the eighteenth aspect of the present invention is characterized in that, in the thirteenth aspect, at least the surface of the second electrode facing the first electrode is surface-modified.
  • the power generation element according to the 19th aspect of the present invention is characterized in that, in any one of the 13th to 18th aspects, the conductive substance contains a Group 4 element.
  • the method for manufacturing a power generation element includes a step of forming a first electrode on a first substrate and a second electrode on the second substrate, which is the same conductive material as the first electrode.
  • each of the first electrode and the second electrode is made of the same conductive substance. Then, by annealing the second electrode, the value of the work function of the second electrode is changed from the value of the work function of the first electrode beyond the value of the work function of the nanoparticles. Thereby, the first electrode and the second electrode having different work functions can be obtained from one conductive substance. Since the first electrode and the second electrode can be obtained from one conductive substance, the raw materials of the first electrode and the second electrode can be shared. Therefore, a method of controlling the work function of the electrode, which can suppress the manufacturing cost of the power generation element, can be obtained.
  • each of the first electrode and the second electrode can be formed by the same film forming apparatus or the same production line. If each of the first electrode and the second electrode is formed by the same film forming apparatus or the same production line, the production cost of the power generation element can be further suppressed.
  • annealing is performed in an oxidizing atmosphere, and at least the surface of the second electrode facing the first electrode is oxidized.
  • the value of the work function of the second electrode can be changed from the value of the work function of the first electrode beyond the value of the work function of the nanoparticles depending on the presence or absence of oxides on the opposing surfaces.
  • the annealing is performed in an oxidizing atmosphere, and the annealing is performed by annealing.
  • (1) Increase the oxidation number of the second oxide film from the oxidation number of the first oxide film (2) Make the thickness of the second oxide film thicker than the thickness of the first oxide film (3)
  • At least one of the passivation transformations of the second oxide film from the first oxide film is performed. For example, by performing at least one of the above (1) to (3), the value of the work function of the second electrode is changed from the value of the work function of the first electrode beyond the value of the work function of the nanoparticles. Can be made to.
  • the oxidizing atmosphere is the atmosphere
  • oxidation of at least the surface of the second electrode facing the first electrode can be performed at a lower cost. Therefore, the manufacturing cost of the power generation element can be further suppressed.
  • annealing is performed in a reducing atmosphere, and at least the surface of the second electrode facing the first electrode is reduced.
  • a state in which the oxide is present on the surface of the first electrode facing the second electrode and no oxide is present on the surface of the second electrode facing the first electrode can be obtained.
  • the value of the work function of the second electrode can be changed from the value of the work function of the first electrode beyond the value of the work function of the nanoparticles depending on the presence or absence of oxides on the opposing surfaces.
  • the annealing is performed in a reducing atmosphere, and the annealing is performed by annealing.
  • (4) Decrease the oxidation number of the second oxide film from the oxidation number of the first oxide film (5) Make the thickness of the second oxide film thinner than the thickness of the first oxide film (6)
  • At least one of the passivation transformations of the second oxide film from the first oxide film is performed. For example, by performing at least one of the above (4) to (6), the value of the work function of the second electrode is changed from the value of the work function of the first electrode beyond the value of the work function of the nanoparticles. Can be made to.
  • each of the first oxide film and the second oxide film before being annealed is a natural oxide film of a conductive substance. Then, annealing is performed in an oxidizing atmosphere with respect to the second oxide film which is a natural oxide film.
  • the oxidation number increases, and the film quality of the second oxide film becomes denser, for example, than the film quality of the first oxide film.
  • the Fermi level of the second oxide film which was a natural oxide film can be changed from the Fermi level of the first oxide film which is still a natural oxide film.
  • the work function value of the second electrode is calculated from the work function value of the first electrode, and the work function of the nanoparticles is calculated. It can be changed beyond the value.
  • annealing is performed under reduced pressure or in an inert atmosphere, and the second electrode is allotropically transformed from the first electrode.
  • the value of the work function of the second electrode can be changed from the value of the work function of the first electrode beyond the value of the work function of the nanoparticles. ..
  • annealing is performed in an active atmosphere, and at least the surface of the second electrode facing the first electrode is surface-modified.
  • the value of the work function of the second electrode exceeds the value of the work function of the nanoparticles from the value of the work function of the first electrode. Can be changed.
  • the conductive substance contains a Group 4 element.
  • Group 4 elements have a high melting point and a relatively small coefficient of thermal expansion and Young's modulus. Therefore, it is a conductive substance that can easily withstand annealing.
  • Group 4 elements are easily available. Among the Group 4 elements, for example, titanium is easily available and inexpensive.
  • the Group 4 element is one of the conductive substances useful for carrying out the method for controlling the work function of the electrode according to any one of the first to tenth aspects.
  • the first electrode is not annealed.
  • the difference between the value of the work function of the first electrode and the value of the work function of the second electrode can be made larger.
  • the first electrode may be annealed.
  • the annealing temperature of the first electrode should be lower than that of the second electrode
  • the annealing time of the first electrode should be shorter than that of the second electrode
  • the annealing energy of the first electrode should be set.
  • the annealing includes at least one of thermal annealing, laser annealing and optical annealing.
  • at least one of thermal annealing, laser annealing, and optical annealing can be selected as the annealing method.
  • each of the first electrode and the second electrode is the same conductive substance, and the state of the surface of the second electrode facing at least the first electrode is at least the first of the first electrodes. It is different from the state of the surface facing the two electrodes. Due to the different states of the facing surfaces, the work function value of the first electrode is ⁇ 1, the work function value of the second electrode is ⁇ 2, and the nano is nano, even though the first electrode and the second electrode are the same conductive substance.
  • the relationship of the value ⁇ N of the work function of the particle, ⁇ 1 ⁇ N ⁇ 2 Can be.
  • the surface of the second electrode facing the first electrode is oxidized.
  • the work function value of the first electrode is ⁇ 1 and the work function value of the second electrode is ⁇ 2, even though the first electrode and the second electrode are the same conductive substance.
  • the relationship of the work function value ⁇ N of the nanoparticles, ⁇ 1 ⁇ N ⁇ 2 Can be.
  • the surface of the second electrode facing the first electrode is reduced.
  • the work function value of the first electrode is ⁇ 1 and the work function value of the second electrode is ⁇ 2, even though the first electrode and the second electrode are the same conductive substance.
  • the relationship of the work function value ⁇ N of the nanoparticles, ⁇ 1 ⁇ N ⁇ 2 Can be.
  • each of the first electrode and the second electrode is the same conductive substance, and a first oxide film of the conductive substance is formed on the surface of the first electrode facing the gap.
  • the second oxide film is (7)
  • the oxidation number of the second oxide film is larger than the oxidation number of the first oxide film (8)
  • the thickness of the second oxide film is thicker than the thickness of the first oxide film (9)
  • the second oxide film Takes at least one state, including a homogenous variant of the first oxide film.
  • the work function of the first electrode is obtained even though each of the first electrode and the second electrode is the same conductive substance.
  • the relationship between the value ⁇ 1 of, the work function value ⁇ 2 of the second electrode, and the work function value ⁇ N of the nanoparticles, ⁇ 1 ⁇ N ⁇ 2 Can be.
  • the second electrode contains an allotropic transformation of the first electrode.
  • the work function values of the first electrode ⁇ 1 and the second electrode are the same even though the first electrode and the second electrode are the same conductive material, respectively.
  • the relationship between the work function value ⁇ 2 of the electrode and the work function value ⁇ N of the nanoparticles, ⁇ 1 ⁇ N ⁇ 2 Can be.
  • At least the surface of the second electrode facing the first electrode is surface-modified.
  • the work function of the first electrode is different even though the first electrode and the second electrode are each the same conductive material.
  • the relationship between the value ⁇ 1, the work function value ⁇ 2 of the second electrode, and the work function value ⁇ N of the nanoparticles, ⁇ 1 ⁇ N ⁇ 2 Can be.
  • the conductive substance contains a Group 4 element.
  • Group 4 elements have a high melting point and a relatively small coefficient of thermal expansion and Young's modulus. Therefore, it is a conductive substance that can easily withstand annealing.
  • Group 4 elements are easily available.
  • titanium is easily available and inexpensive.
  • the Group 4 element is one of the conductive substances useful for carrying out the power generation element according to any one of the thirteenth to eighteenth aspects.
  • the first electrode is formed on the first substrate, the second electrode which is the same conductive material as the first electrode is formed on the second substrate, and the second electrode is formed.
  • the electrode is annealed to change the work function of the second electrode from the work function of the first electrode.
  • the first electrode and the second electrode are opposed to each other through the gap, and nanoparticles having a work function between the work function of the first electrode and the changed work function of the second electrode are filled in the gap. ..
  • the work function of the second electrode can be changed from the work function of the first electrode while using the same conductive substance as the first electrode for the second electrode. Therefore, it is possible to obtain a method for manufacturing a power generation element that can suppress the manufacturing cost of the power generation element.
  • FIG. 1A is a schematic cross-sectional view showing an example of a power generation element according to the first embodiment of the present invention.
  • FIG. 1B is a schematic cross-sectional view showing an example of a power generation device using a power generation element according to the first embodiment of the present invention.
  • FIG. 2A is a schematic cross-sectional view showing an example of the intermediate portion
  • FIG. 2B is a schematic cross-sectional view showing another example of the intermediate portion.
  • FIG. 3 is a diagram showing the relationship between the work functions of the first electrode, the second electrode, and the nanoparticles.
  • FIG. 4 is a diagram showing the relationship between the work function of the electrode and the annealing temperature.
  • FIG. 5 is a diagram showing the relationship between the work functions of the first electrode, the second electrode, and the nanoparticles.
  • FIG. 6 is a schematic cross-sectional view showing an example of the power generation element according to the second embodiment of the present invention.
  • FIG. 7 is a diagram showing the relationship between the work functions of the first electrode, the second electrode, and the nanoparticles.
  • FIG. 8 is a schematic cross-sectional view showing an example of the power generation element according to the third embodiment of the present invention.
  • FIG. 9 is a diagram showing the relationship between the work functions of the first electrode, the second electrode, and the nanoparticles.
  • FIG. 10 is a schematic cross-sectional view showing an example of a power generation element according to a fourth embodiment of the present invention.
  • FIG. 10 is a schematic cross-sectional view showing an example of a power generation element according to a fourth embodiment of the present invention.
  • FIG. 11 is a schematic cross-sectional view showing an example of the power generation element according to the fifth embodiment of the present invention.
  • FIG. 12 is a schematic cross-sectional view showing an example of the power generation element according to the sixth embodiment of the present invention.
  • FIG. 13 is a schematic cross-sectional view showing an example of the power generation element according to the seventh embodiment of the present invention.
  • FIG. 14 is a flow chart showing an example of a method for manufacturing a power generation element according to an eighth embodiment of the present invention.
  • 15 (a) to 15 (d) are schematic block diagrams showing an example of an electronic device provided with a power generation element.
  • 15 (e) to 15 (h) are schematic block diagrams showing an example of an electronic device including a power generation device including a power generation element.
  • FIG. 1A is a schematic cross-sectional view showing an example of a power generation element according to the first embodiment of the present invention.
  • FIG. 1B is a schematic cross-sectional view showing an example of a power generation device using a power generation element according to the first embodiment of the present invention.
  • the power generation element 1 includes a first electrode 11, a second electrode 12, and an intermediate portion 13.
  • the first electrode 11 is provided on the first substrate 21.
  • the first electrode 11 is the cathode K in this embodiment.
  • the first substrate 21 is an insulating or conductive substrate. In this embodiment, an insulating substrate is used for the first substrate 21.
  • An example of an insulating substrate is a glass substrate.
  • the second electrode 12 is provided on the second substrate 22.
  • the second electrode 12 is the anode A in this embodiment.
  • the work function value ⁇ A of the second electrode 12 is different from the work function value ⁇ K of the first electrode 11.
  • the work function value ⁇ K is smaller than the work function value ⁇ A ( ⁇ K ⁇ A).
  • the second electrode 12 faces the first electrode 11 via the gap G.
  • the second substrate 22 is an insulating or conductive substrate.
  • each of the first substrate 21 and the second substrate 22 is a substrate made of the same insulating substance or a substrate made of the same conductive substance.
  • the same glass substrate as the first substrate 21 is used for the second substrate 22.
  • the substrate is not limited to a strong substrate, and a flexible substrate can also be used.
  • the power generation element 1 has a support portion 23 between the first substrate 21 and the second substrate 22.
  • the height H23 of the support portion 23 in the Z direction substantially determines the inter-electrode gap GE between the first electrode 11 and the second electrode 12.
  • X, Y, and Z shown in FIG. 1A indicate a three-dimensional Cartesian coordinate system.
  • An example of the gap between electrodes GE is a finite value of 1 ⁇ m or less. When the gap GE between electrodes is narrowed, the output of electrical energy is improved.
  • FIG. 2A is a schematic cross-sectional view showing an example of the intermediate portion 13.
  • the intermediate portion 13 is provided in the gap G.
  • the intermediate portion 13 is a portion that moves the electrons e emitted from the first electrode 11 (cathode K) to the second electrode 12 (anode A).
  • FIG. 2A shows a portion of the second electrode 12 where the oxide 12a will be described later.
  • the intermediate portion 13 contains nanoparticles 14.
  • the work function value ⁇ N of the nanoparticles 14 is between the work function value ⁇ K of the first electrode 11 and the work function value ⁇ A of the second electrode 12 ( ⁇ K ⁇ N ⁇ A). A substance having such a work function value ⁇ N is selected as the nanoparticles 14.
  • the particle size of the nanoparticles 14 is, for example, 2 nm or more and 10 nm or less.
  • the nanoparticles 14 may have, for example, an average particle size (for example, D50) of 3 nm or more and 8 nm or less.
  • the average particle size can be measured by using, for example, a particle size distribution measuring instrument.
  • a particle size distribution measuring instrument for example, a particle size distribution measuring instrument using a laser diffraction / scattering method (for example, Nanotrac Wave II-EX150 manufactured by Microtrac BEL) may be used.
  • the nanoparticles 14 have, for example, an insulating film 14a on the surface thereof.
  • an insulating metal compound and an insulating organic compound can be selected.
  • the insulating metal compound include, for example, silicon oxide and alumina.
  • the insulating organic compound include alkanethiol (for example, dodecanethiol) and the like.
  • the thickness of the insulating film 14a is, for example, a finite value of 20 nm or less.
  • the electrons e are, for example, between the first electrode 11 (cathode K) and the nanoparticles 14, and the nanoparticles 14 and the second electrode 12 ( It can move to and from the anode A) using the tunnel effect. Therefore, for example, improvement in power generation efficiency of the power generation element 1 can be expected.
  • the inside of the gap G is filled with the solvent 15.
  • the nanoparticles 14 are dispersed in the solvent 15.
  • the solvent 15 for example, a liquid having a boiling point of 60 ° C. or higher can be used. By using such a liquid, it is possible to suppress the vaporization of the solvent 15 even when the power generation element 1 is used in an environment of room temperature (for example, 15 ° C. to 35 ° C.) or higher. As a result, deterioration of the power generation element 1 due to vaporization of the solvent 15 can be suppressed.
  • a liquid at least one of an organic solvent and water can be selected.
  • the organic solvent examples include methanol, ethanol, toluene, xylene, tetradecane, alkanethiol and the like.
  • the solvent 15 is preferably a liquid having a high electrical resistance value and being insulating. Further, when the nanoparticles 14 are dispersed in the solvent 15, as shown by the arrow in FIG. 2A, the movement of the electrons e can be further promoted by utilizing the movement of the nanoparticles 14. ..
  • FIG. 2B is a schematic cross-sectional view showing another example of the intermediate portion 13.
  • the nanoparticles 14 may be filled in the gap G without using the solvent 15. Note that FIG. 2B shows the portion of the oxide 12a described later in the second electrode 12.
  • the power generation element 1 the electron emission phenomenon due to the absolute temperature generated between the first electrode 11 and the second electrode 12 can be used. Therefore, the power generation element 1 can convert thermal energy into electrical energy even when the temperature difference between the first electrode 11 and the second electrode 12 is small. Further, the power generation element 1 can convert thermal energy into electrical energy even when there is no temperature difference between the first electrode 11 and the second electrode 12 or when a single heat source is used.
  • each of the first electrode 11 and the second electrode 12 is the same conductive substance. However, the state of the surface of the second electrode 12 facing the gap G is different from the state of the surface of the first electrode 11 facing the gap G. Due to the difference in the state of the surface facing the gap G, although the first electrode 11 and the second electrode 12 are the same conductive material, the work function value ⁇ K of the first electrode 11 and the second electrode 12 The relationship between the work function value ⁇ A and the work function value ⁇ N of the nanoparticles 14 ⁇ K ⁇ N ⁇ A Can be.
  • the state of the surface facing the gap G is different is that, for example, the surface of the first electrode 11 facing the gap G has no oxide, and the surface of the second electrode 12 facing the gap G has no oxide.
  • the oxide 12a is, for example, an oxide film of a conductive substance. Another example in which the state of the surface facing the gap G is different will be described later.
  • the amount of emitted electrons e depends not only on the thermal energy but also on the difference between the work function of the first electrode 11 and the work function of the second electrode 12. Further, the amount of emitted electrons e tends to increase as the work function of the first electrode 11 becomes smaller.
  • the amount of moving electrons e can be increased, for example, by increasing the difference in work function between the first electrode 11 and the second electrode 12, or by reducing the gap GE between the electrodes.
  • the amount of electrical energy generated by the power generation element 1 can be increased by considering at least one of increasing the difference in work functions and reducing the gap GE between electrodes.
  • the power generation device 100 includes a power generation element 1, a first external terminal 101, and a second external terminal 102.
  • the first external terminal 101 is electrically connected to the first electrode 11.
  • the first external terminal 101 is a cathode K.
  • the second external terminal 102 is electrically connected to the second electrode 12.
  • the second external terminal 102 is the anode A.
  • the power generation device 100 including the power generation element 1 is mounted or installed on a heat source (not shown), and the electric energy generated by the power generation element 1 based on the heat energy of the heat source is used as the first external terminal 101 and the second outside. Output to the load R via the terminal 102.
  • the load R is electrically connected to the first external terminal 101 via the first external wiring 111.
  • the other end of the load R is electrically connected to the second external terminal 102 via the second external wiring 112.
  • the load R indicates, for example, an electrical device.
  • the load R is driven by using the power generation device 100 as a main power source or an auxiliary power source.
  • Examples of the heat source of the power generation element 1 include electronic devices or electronic components such as a CPU (Central Processing Unit), light emitting elements such as LEDs (Light Emitting Diodes), engines such as automobiles, factory production equipment, human bodies, sunlight, and the like. Environmental temperature etc. can be used.
  • electronic devices, electronic components, light emitting elements, engines, production equipment, and the like are artificial heat sources.
  • the human body, sunlight, environmental temperature, etc. are natural heat sources.
  • the power generation device 100 can be provided inside a mobile device such as an IoT (Internet of Things) device and a wearable device, or a self-supporting sensor terminal, and can be used as a substitute or an auxiliary for a battery. Further, the power generation device 100 can also be applied to a larger power generation device such as solar power generation.
  • FIG. 3 is a diagram showing the relationship between the work functions of the first electrode 11, the second electrode 12, and the nanoparticles 14.
  • FIG. 3 shows a case where the work function of each of the first electrode 11 and the second electrode 12 is smaller than the work function of the nanoparticles.
  • each of the first electrode 11 and the second electrode 12 is Ti (titanium) and the nanoparticles 14 are Au (gold).
  • the inventors of the present case make the work function of the first electrode 11 different from the work function of the second electrode 12 even when the first electrode 11 and the second electrode 12 are made of the same conductive substance? I considered whether or not. If feasible, it is possible to break through the current situation in which the first electrode 11 and the second electrode 12 are each made of different conductive substances. For example, Ti is selected as the conductive substance of the first electrode 11, and Pt (platinum) is selected as the conductive substance of the second electrode 12. If this situation can be overcome, at least: -It is necessary to purchase raw materials for each different conductive substance-It is necessary to prepare an expensive film forming equipment or an expensive production line for each different conductive substance. It is possible to eliminate the situation that there is, and to suppress the manufacturing cost of the power generation element.
  • FIG. 4 is a diagram showing the relationship between the work function of the electrode and the annealing temperature.
  • test piece TP1 was prepared.
  • the test piece has a Ti film formed on a glass substrate as the first electrode 11 and the second electrode 12.
  • Six test pieces were prepared (first test piece TP1 to sixth test piece TP6).
  • the second test piece TP2 to the sixth test piece TP6 were subjected to thermal annealing at 100 ° C., 150 ° C., 200 ° C., 250 ° C., and 300 ° C., respectively.
  • the first test piece TP1 was left at room temperature (25 ° C. in this embodiment).
  • Atmosphere Atmosphere Annealing time: 1 minute Pressure: Atmospheric pressure (approx. 101300 Pa) Cooling after heating: None (return to room temperature only)
  • FIG. 4 shows the difference between the work function of the Ti film and the work function of the nanoparticles 14 with the work function of the nanoparticles 14 as the reference (0).
  • Au was assumed for the nanoparticles 14.
  • the work function of Au was set to, for example, 5.4 eV.
  • First test piece TP1 Approximately -0.58 eV (without annealing: 25 ° C)
  • Second test piece TP2 Approximately -0.5 eV (with annealing: 100 ° C)
  • Third test piece TP3 Approximately -0.3 eV (with annealing: 150 ° C)
  • Fourth test piece TP4 Approximately +0.07 eV (with annealing: 200 ° C)
  • the value of the work function of the first test piece TP1 to the third test piece TP3 is lower than the work function of the nanoparticles 14.
  • the value of the work function of the fourth test piece TP4 to the sixth test piece TP6 is higher than the work function of the nanoparticles 14. That is, by annealing, the value of the work function changes beyond the value of the work function of the nanoparticles 14. From this finding, for example, by annealing the second electrode 12, the value of the work function of the second electrode 12 is changed from the value of the work function of the first electrode 11 beyond the value of the work function of the nanoparticles 14. It was confirmed that it was possible to make it.
  • the annealing temperature is preferably 300 ° C. or higher and lower than the melting point of the Group 4 element.
  • FIG. 5 is a diagram showing the relationship between the work functions of the first electrode 11, the second electrode 12, and the nanoparticles 14.
  • the work function value of the second electrode 12 can be made larger than the work function value of the nanoparticles 14.
  • the first electrode 11 and the second electrode 12 are the same conductive material, but the first electrode is the first.
  • the relationship between the work function value ⁇ K of the electrode 11, the work function value ⁇ A of the second electrode 12, and the work function value ⁇ N of the nanoparticles 14. ⁇ K ⁇ N ⁇ A Can be. That is, in the power generation element 1, although the first electrode 11 and the second electrode 12 are each the same conductive material, the first electrode 11 can be used as the cathode K and the second electrode 12 can be used as the anode A. Was confirmed.
  • a power generation element such as the power generation element 1
  • Al aluminum
  • Pt for the anode A
  • Au for the nanoparticles 14.
  • the difference between the work function of Al and the work function of Au is about ⁇ 0.88 eV.
  • the difference between the work function of Pt and the work function of Au is about +0.22 eV.
  • the absolute value of the work function difference is about 1.1 eV.
  • the difference between the work function of the first test piece TP1 and the work function of Au is about -0.58 eV.
  • the difference between the work function of the sixth test piece TP6 and the work function of Au is about +0.25 eV.
  • the absolute value of the work function difference is about 0.83 eV. This absolute value is different from the absolute value of the difference in work functions in the power generation element under consideration. However, if the absolute value of the difference between the work functions is about 0.83 eV, it can function as a power generation element.
  • the atmosphere was the atmosphere under the conditions of thermal annealing.
  • the atmosphere contains O 2 (oxygen molecules).
  • the atmosphere is one of the oxidizing atmospheres. That is, it is considered that the Ti film imitating the second electrode 12 is annealed, so that the Ti film is oxidized or the Ti film is further oxidized.
  • By annealing the second electrode 12 at least the state of the surface of the second electrode 12 can be made different from the state of the surface of the first electrode 11. If the surface condition of the second electrode 12 is different from the surface condition of the first electrode 11, the first electrode 11 (cathode K) is different from the surface condition of the first electrode 11 even though the first electrode 11 and the second electrode 12 are the same conductive material. ),
  • the first embodiment it is possible to provide a method of controlling the work function of the electrode and a method of manufacturing the power generation element and the power generation element, which can suppress the manufacturing cost of the power generation element.
  • the conductive substance is not limited to Ti. Any conductive substance that can at least change the surface condition by annealing may be used.
  • the conductive substance is preferably selected from Group 4 elements. This is because Group 4 elements have a high melting point and a relatively small coefficient of thermal expansion and Young's modulus. Therefore, it is a conductive substance that can easily withstand annealing.
  • Group 4 elements are easily available. Among the Group 4 elements, for example, Ti is easily available and inexpensive.
  • Group 4 elements are one of the conductive substances useful in carrying out the embodiments of the present invention. This matter is common to all the embodiments described later.
  • the annealing method is not limited to thermal annealing. At least, any annealing method that can make the surface condition of the electrode different can be used. Examples of such annealing include thermal annealing, laser annealing, optical annealing, and the like. As the annealing method, one of thermal annealing, laser annealing and optical annealing can be selected. Furthermore, these annealing methods can be combined in various ways. That is, in the first embodiment, the annealing may include at least one of thermal annealing, laser annealing, and optical annealing. This matter is common to all the embodiments described later.
  • the annealing condition was that the atmosphere was the atmosphere.
  • the atmosphere is one of the oxidizing atmospheres. If the atmosphere is atmospheric, no oxidizer is required. Therefore, annealing can be performed at low cost.
  • the oxidizing atmosphere is not limited to the atmosphere. Oxidizing atmosphere, for example ⁇ Atmosphere containing more oxygen molecules (O 2 ) than the atmosphere ⁇ Atmosphere containing more water vapor than the atmosphere ⁇ Atmosphere containing oxygen allotropes (O 3 (ozone), oxygen clusters, etc.) ⁇ Atmosphere containing oxygen compounds ⁇ Hydroxy
  • the atmosphere may contain a compound having a group ( ⁇ OH). This matter is common to all the embodiments described later.
  • the first electrode 11 was not annealed.
  • the first electrode 11 is not limited to not being annealed.
  • the first electrode 11 may be annealed.
  • annealing the first electrode 11 -The annealing temperature of the first electrode 11 is lower than that of the second electrode 12.
  • -The annealing time of the first electrode 11 is shorter than that of the second electrode 12.
  • -The annealing energy of the first electrode 11 is the second electrode 12. It is better to satisfy at least one of the lower than. As a result, the difference between the value of the work function of the first electrode 11 and the value of the work function of the second electrode 12 can be kept large.
  • the work function value of the second electrode 12 is made larger than the work function value of the first electrode 11 by annealing the second electrode 12, but on the contrary, the work function of the second electrode 12 is increased. It is also possible to make the value of the function smaller than the value of the work function of the first electrode 11. This matter is common to all the embodiments described later.
  • 2nd Embodiment Power generation element: 2nd example
  • Some conductive materials form a natural oxide film on their surface when exposed to the atmosphere. For example, Ti. When Ti is exposed to the atmosphere, a natural oxide film is formed on its surface. It should be noted that this matter does not deny the first embodiment. This is because the formation of the natural oxide film can be suppressed unless the Ti film is exposed to an oxidizing atmosphere such as the atmosphere after the Ti film is formed on the substrate, for example, by load locking.
  • FIG. 6 is a schematic cross-sectional view showing an example of a power generation element according to the second embodiment of the present invention.
  • the schematic cross section shown in FIG. 6 corresponds to the schematic cross section shown in FIG. 1 (a).
  • the power generation element 1b according to the second embodiment is different from the power generation element 1 according to the first embodiment in that it is conductive on at least the surface of the first electrode 11 facing the second electrode 12.
  • the first oxide film 11b of the sex substance is present, and the second oxide film 12b of the conductive substance is present on the surface of the second electrode 12 facing at least the first electrode 11.
  • FIG. 6 shows the case B, which is the easiest to see in the drawing.
  • the oxides of the oxidation number (I) to the oxidation number (II) contain more oxides of the oxidation number (III) to the oxidation number (IV), and the second oxide film 12b corresponds to a state in which the oxides of the oxidation number (iii) to the oxidation number (IV) contain more oxides of the oxidation number (I) to the oxidation number (II).
  • the first oxide film 11b has Ti 2 O (oxidation number (I)) and TiO (oxidation number (II)) as Ti 2 O 3 (oxidation number (II)). (III)) and TiO 2 (oxidation number (IV)) are contained in a larger amount, and the second oxide film 12b contains more Ti 2 O 3 and TIO 2 than Ti 2 O and TIO.
  • Ti forms a natural oxide film when exposed to the atmosphere, and the main oxides of the natural oxide film of Ti can be considered to be Ti 2 O and Ti O having a low oxidation number.
  • the film quality of the second oxide film 12b is the film quality of the first oxide film 11b, although it depends on the conditions such as the annealing temperature. For example, it can be made more precise. It can be considered that this is because the oxidation number is increased as compared with the state of the natural oxide film.
  • the work function of a Ti film having Ti 2 O having a low oxidation number as a main oxide on the surface is close to the work function of Ti itself.
  • the Fermi level of the second oxide film 12b which was a natural oxide film, can be changed from the Fermi level of the first oxide film 11b, which remains the natural oxide film. From this, it is possible to give a difference in work function between the first electrode 11 and the second electrode 12.
  • the power generation element 1b according to the case B can also be sufficiently functioned as a power generation element.
  • TiO 2 becomes anatase type when the annealing temperature is, for example, 650 to 750 ° C., and becomes rutile type when the annealing temperature exceeds, for example, 750 ° C.
  • the value of the work function of the second electrode 12 is the work function of the nanoparticles 14 from the value of the work function of the first electrode 11. Can be varied beyond the value of.
  • Ti also undergoes allotropic transformation.
  • the crystal structure of Ti is a fine cubic lattice (hcp) at room temperature (25 ° C.), but when it is annealed at an annealing temperature of 870 to 890 ° C., it undergoes an allotropic transformation into a body-centered cubic lattice (bcc).
  • Zr zirconium
  • hcp fine cubic lattice
  • bcc body-centered cubic lattice
  • anatase-type TiO 2 is an n-type semiconductor having a bandgap of about 3.1 to 3.3 eV. Therefore, anatase-type TiO 2 exhibits photocatalytic activity by irradiation with ultraviolet rays, for example.
  • FIG. 7 is a diagram showing the relationship between the work functions of the first electrode, the second electrode, and the nanoparticles.
  • the work function of the second electrode 12 can be largely different from the work function of the first electrode 11.
  • cases A to C can overlap, and annealing is performed in an oxidizing atmosphere, and by this annealing, (1) Increase the oxidation number of the second oxide film 12b from the oxidation number of the first oxide film 11b (2) Make the thickness of the second oxide film 12b thicker than the thickness of the first oxide film 11b. (3) Passivation of the second oxide film 12b from the first oxide film 11b At least one of the above (1) to (3) may be performed.
  • the first embodiment and the second embodiment showed an example in which the second electrode 12 is oxidized by annealing.
  • Annealing is not limited to the case of oxidation.
  • the value of the work function of the second electrode 12 exceeds the value of the work function of the nanoparticles 14 from the work function of the first electrode 11.
  • the value of the work function of the first electrode 11 can be changed from the second electrode 12 beyond the value of the work function of the nanoparticles 14.
  • Annealing in this case is performed in a reducing atmosphere.
  • FIG. 8 is a schematic cross-sectional view showing an example of the power generation element according to the third embodiment of the present invention.
  • the schematic cross section shown in FIG. 8 corresponds to the schematic cross section shown in FIG. 1 (a).
  • the power generation element 1c according to the third embodiment is different from the power generation element 1 according to the first embodiment in that the first electrode 11 is conductive on at least the surface facing the second electrode 12. There is a reducing layer 11c of the sex substance. In this embodiment, there is a conductive substance on the surface of the second electrode 12 facing at least the first electrode 11. An example of a conductive substance is titanium oxide. An example of the reduction layer 11c is Ti.
  • FIG. 9 is a diagram showing the relationship between the work functions of the first electrode, the second electrode, and the nanoparticles.
  • the fourth embodiment is an example according to the second embodiment, in which the first oxide film 11b is provided on the surface of the first electrode 11 facing at least the second electrode 12, and at least the first electrode of the second electrode 12 is provided.
  • the second oxide film 12b is provided on the surface facing the 11.
  • the difference between the power generation element 1d according to the fourth embodiment and the power generation element 1b according to the second embodiment is that the first oxide film 11b is reduced by annealing, and the reduction layer 11c is present in the surface region of the first oxide film 11b. That is.
  • the second oxide film 12b is a natural oxide film or a chemically oxidized oxide film.
  • the first oxide film 11b takes at least one of the following states.
  • Case D The oxidation number of the first oxide film 11b is smaller than the oxidation number of the second oxide film 12b.
  • Case E The thickness of the first oxide film 11b is thinner than the thickness of the second oxide film 12b.
  • Case F The first oxide film 11b contains an allotropic transformation of the second oxide film 12b.
  • FIG. 10 shows the case E, which is the easiest to see in the drawing.
  • the reducing layer 11c is formed in the surface region of the first oxide film 11b, and the thickness of the first oxide film 11b is reduced by the reducing layer 11c.
  • the first oxide film 11b may disappear due to the reducing layer 11c. When it disappears, the first oxide film 11b disappears, and the structure is structurally similar to that shown in FIG. 1A.
  • Cases D to F can overlap, and annealing is performed in a reducing atmosphere, and by this annealing, (4) Decrease the oxidation number of the first oxide film 11b from the oxidation number of the second oxide film 12b (5) Make the thickness of the first oxide film 11b thinner than the thickness of the second oxide film 12b (5) 6) Passivation transformation from the first oxide film 11b and the second oxide film 12b At least one of the above (4) to (6) may be performed.
  • Case D to Case F can be read as follows.
  • Case D1 The oxidation number of the second oxide film 12b is larger than the oxidation number of the first oxide film 11b.
  • Case E1 The thickness of the second oxide film 12b is thicker than the thickness of the first oxide film 11b.
  • Case F1 The second oxide film 12b contains an allotropic transformation of the first oxide film 11b.
  • Cases D1 to F1 have the same relationship as cases A to C of the second embodiment. Therefore, in the fourth embodiment, the description of the second embodiment will be quoted, and the specific description thereof will be omitted.
  • Annealing is not limited to being carried out in an oxidizing atmosphere or a reducing atmosphere, but can also be carried out under reduced pressure or in an inert atmosphere.
  • the second electrode 12 undergoes allotropic transformation from, for example, the first electrode 11.
  • the allotropic transformation does not have to occur in the entire second electrode 12, but may occur in a part of the second electrode 12.
  • FIG. 11 is a schematic cross-sectional view showing an example of the power generation element according to the fifth embodiment of the present invention.
  • the schematic cross section shown in FIG. 11 corresponds to the schematic cross section shown in FIG. 1 (a).
  • the power generation element 1e according to the fifth embodiment is different from the power generation element 1 according to the first embodiment in that the second electrode 12 is, for example, allotropically transformed from the first electrode 11. It is that you are.
  • FIG. 11 schematically shows the difference between the crystal structure of the first electrode 11 and the crystal structure of the second electrode 12.
  • the second electrode 12 itself is allotropically transformed from the first electrode 11.
  • the second electrode 12 itself may be allotropically transformed from the first electrode 11.
  • the second electrode 12 may contain an allotropic transformation product of the first electrode.
  • Sixth Embodiment (Method of controlling work function of electrode) Annealing can be performed in an active atmosphere.
  • the annealing in an active atmosphere, at least the surface of the second electrode 12 facing the first electrode 11 is surface-modified.
  • FIG. 12 is a schematic cross-sectional view showing an example of the power generation element according to the sixth embodiment of the present invention.
  • the schematic cross section shown in FIG. 12 corresponds to the schematic cross section shown in FIG. 1 (a).
  • the power generation element 1f according to the sixth embodiment is different from the power generation element 1 according to the first embodiment in that the second electrode 12 is surface-modified and at least the first of the second electrodes 12 is formed.
  • the surface modification layer 12d is provided on the surface facing the electrode 11.
  • the surface modification described in this specification is to diffuse or adhere the surface modification substance to the conductive substance of the second electrode 12.
  • Examples of surface modification are nitriding, boring, carburizing and the like.
  • the state of the surface of the second electrode 12 facing at least the first electrode 11 can be changed to the state of the surface of the first electrode 11 facing at least the second electrode 12. Can be different from. Therefore, as in the first embodiment, although the first electrode 11 and the second electrode 12 are each the same conductive substance, the work function value ⁇ K of the first electrode 11 and the work function of the second electrode 12 The relationship between the value ⁇ A and the work function value ⁇ N of the nanoparticles 14 ⁇ K ⁇ N ⁇ A Can be.
  • FIG. 13 is a schematic cross-sectional view showing an example of the power generation element according to the seventh embodiment of the present invention.
  • the schematic cross section shown in FIG. 13 corresponds to the schematic cross section shown in FIG. 1 (a).
  • the difference between the power generation element 1g according to the seventh embodiment and the power generation element 1 according to the first embodiment is that there is no support portion 23, and the first flexible substrate 21a and the second flexible substrate 22a Is coupled in the vicinity of the periphery of the first electrode 11 and the second electrode 12.
  • the bonding may be, for example, bonding using an adhesive. It is also possible to omit the support portion 23 from the structure of the power generation element, as in the case of the power generation element 1g.
  • the power generation element 1g since there is no support portion 23, the number of parts of the power generation element can be reduced, which is useful for further suppressing the manufacturing cost of the power generation element.
  • the substrates are the first flexible substrate 21a and the second flexible substrate 22a, but the substrate is not limited to the flexible substrate.
  • the power generation element 1g may have a structure in which at least one of the first electrode 11 and the second electrode 12 is formed on a strong substrate having a recess, and the two substrates are bonded to each other.
  • 1 g of the power generation element can be applied in all the above-described embodiments.
  • FIG. 14 is a flow chart showing an example of a method for manufacturing a power generation element according to an eighth embodiment of the present invention.
  • the first electrode 11 is formed on the first substrate 21 (ST.1).
  • the second electrode 12, which is the same conductive substance as the first electrode 11, is formed on the second substrate 22 (ST.2).
  • ST. 1 and ST. 2 does not need to be divided into two steps.
  • a film of a conductive substance is formed on the substrate, and the substrate on which the film of the conductive substance is formed is divided into two or more to have a first substrate 21 having a first electrode 11 and a second electrode 12. It is also possible to form the second substrate 22.
  • ST. 1 and ST. 2 is defined to include both the case of dividing into two steps and the case of making one step.
  • the second electrode 12 is annealed, and the work function of the second electrode 12 is changed from the work function of the first electrode 11 (ST.3).
  • the annealing described in the above-described embodiment is used.
  • the annealing method can be selected from at least one of thermal annealing, laser annealing and optical annealing, and these annealing methods can be combined in various ways.
  • the first electrode 11 and the second electrode 12 are opposed to each other via the gap G (ST.4).
  • the nanoparticles 14 are introduced into the gap G (ST.5).
  • the intermediate portion 13 containing the nanoparticles 14 is formed in the gap G.
  • the nanoparticles 14 are selected to have a work function between the work function of the first electrode 11 and the changed work function of the second electrode 12.
  • a method for introducing the nanoparticles 14 into the gap G for example, a hole introduction method through holes, a slit introduction method utilizing a capillary phenomenon, or the like can be used.
  • the hole introduction method an injection hole is formed in the first electrode 11, the second electrode 12, or the support portion 23, and the nanoparticles 14 dispersed in the solvent 15 are formed through the formed injection hole, for example, in the gap G. Introduce inside.
  • the injection holes are sealed.
  • a thin slit leading to the gap G is formed between the support portions 23, and the nanoparticles 14 dispersed in the solvent 15 are used, for example, by utilizing the capillary phenomenon through the formed slit. Introduce into gap G. After introduction, the slits are sealed.
  • the power generation elements 1, 1b to 1 g according to the above-described embodiment of the present invention can be manufactured in the flow as shown in FIG.
  • the second electrode 12 is used instead of forming another conductive substance film such as a plating film, a deposited film, etc. on the surface of the second electrode 12. At least the state of the surface facing the first electrode 11 is different from the state of the surface of the first electrode 11 facing at least the second electrode 12. For example, in the method for manufacturing a power generation element according to this embodiment, a surface of the second electrode 12 facing at least the first electrode 11 is formed. ⁇ Oxidizes ⁇ Reduces ⁇ Allotropic transformation ⁇ Surface modification.
  • the work function of the second electrode 12 is changed from the work function of the first electrode 11 by using the conductive substance of the second electrode 12 itself, instead of adhering a film of another conductive substance.
  • the variation in the thickness of the second electrode 12 can be reduced as compared with the case where a film of another conductive substance is attached, which is also effective in reducing the variation in the characteristics of the power generation element.
  • 15 (a) to 15 (d) are schematic block diagrams showing an example of an electronic device provided with a power generation element.
  • 15 (e) to 15 (h) are schematic block diagrams showing an example of an electronic device including a power generation device including a power generation element.
  • the electronic device (electric product) 500 includes an electronic component (electronic component) 501, a main power source 502, and an auxiliary power source 503.
  • Each of the electronic device 500 and the electronic component 501 is an electrical device (electrical device).
  • the electronic component 501 is driven by using the main power supply 502 as a power source.
  • Examples of the electronic component 501 include a CPU, a motor, a sensor terminal, lighting, and the like.
  • the electronic device 500 includes an electronic device that can be controlled by a built-in master (CPU).
  • the electronic component 501 includes, for example, at least one of a motor, a sensor terminal, a lighting, and the like, the electronic device 500 includes an external master, or an electronic device that can be controlled by a person.
  • the main power source 502 is, for example, a battery. Batteries also include rechargeable batteries.
  • the positive terminal (+) of the main power supply 502 is electrically connected to the Vcc terminal (Vcc) of the electronic component 501.
  • the negative terminal (-) of the main power supply 502 is electrically connected to the GND terminal (GND) of the electronic component 501.
  • the auxiliary power supply 503 is a power generation element.
  • the power generation element includes, for example, at least one of the power generation elements 1, 1b to 1 g described in each of the embodiments.
  • the power generation elements 1, 1b to 1 g are collectively referred to as a power generation element 1.
  • the anode of the power generation element 1 (for example, the first electrode 11) connects the GND terminal (GND) of the electronic component 501, the negative terminal (-) of the main power supply 502, or the GND terminal (GND) and the negative terminal (-). It is electrically connected to the wiring to be used.
  • the cathode of the power generation element 1 connects the Vcc terminal (Vcc) of the electronic component 501, the positive terminal (+) of the main power supply 502, or the Vcc terminal (Vcc) and the positive terminal (+). It is electrically connected to the wiring to be used.
  • the auxiliary power supply 503 is used in combination with the main power supply 502, for example, as a power source for assisting the main power supply 502 or as a power source for backing up the main power supply 502 when the capacity of the main power supply 502 is exhausted. be able to.
  • the main power source 502 is a rechargeable battery
  • the auxiliary power source 503 can also be used as a power source for charging the battery.
  • the main power source 502 may be the power generation element 1.
  • the anode of the power generation element 1 is electrically connected to the GND terminal (GND) of the electronic component 501.
  • the cathode of the power generation element 1 is electrically connected to the Vcc terminal (Vcc) of the electronic component 501.
  • the electronic device 500 shown in FIG. 15B includes a power generation element 1 used as a main power source 502 and an electronic component 501 that can be driven by the power generation element 1.
  • the power generation element 1 is an independent power source (for example, an off-grid power source). Therefore, the electronic device 500 can be made, for example, a self-supporting type (stand-alone type).
  • the power generation element 1 is an energy harvesting type (energy harvesting type). In the electronic device 500 shown in FIG. 15B, it is not necessary to replace the battery.
  • the electronic component 501 may include the power generation element 1.
  • the anode of the power generation element 1 is electrically connected to, for example, the GND wiring of a circuit board (not shown).
  • the cathode of the power generation element 1 is electrically connected to, for example, the Vcc wiring of a circuit board (not shown).
  • the power generation element 1 can be used as an electronic component 501, for example, an auxiliary power supply 503.
  • the power generation element 1 can be used as, for example, the main power source 502 of the electronic component 501.
  • the electronic device 500 may include a power generation device 100.
  • the power generation device 100 includes a power generation element 1 as a source of electric energy.
  • the embodiment shown in FIG. 15D includes a power generation element 1 in which the electronic component 501 is used as the main power source 502.
  • the embodiment shown in FIG. 15H includes a power generation device 100 in which the electronic component 501 is used as the main power source.
  • the electronic component 501 has an independent power source. Therefore, the electronic component 501 can be made, for example, a self-standing type.
  • the self-supporting electronic component 501 can be effectively used, for example, in an electronic device including a plurality of electronic components and in which at least one electronic component is separated from another electronic component.
  • An example of such an electronic device 500 is a sensor.
  • the sensor includes a sensor terminal (slave) and a controller (master) away from the sensor terminal.
  • Each of the sensor terminal and the controller is an electronic component 501. If the sensor terminal includes the power generation element 1 or the power generation device 100, it becomes a self-supporting sensor terminal, and there is no need to supply electric power by wire. Since the power generation element 1 or the power generation device 100 is an energy harvesting type, it is not necessary to replace the battery.
  • the sensor terminal can also be regarded as one of the electronic devices 500. In addition to the sensor terminal of the sensor, the sensor terminal regarded as the electronic device 500 further includes, for example, an IoT wireless tag and the like.
  • the electronic device 500 uses a power generation element 1 that converts thermal energy into electrical energy and a power generation element 1 as a power source. It includes an electronic component 501 that can be driven.
  • the electronic device 500 may be an autonomous type (autonomous type) having an independent power supply. Examples of autonomous electronic devices include robots and the like. Further, the electronic component 501 including the power generation element 1 or the power generation device 100 may be an autonomous type having an independent power source. Examples of autonomous electronic components include movable sensor terminals and the like.

Abstract

[Problem] To provide a method that is for controlling work function of an electrode and that enables reduction of production costs of a power generation element. [Solution] A power generation element according to one embodiment of the present invention comprises: a first electrode 11; a second electrode 12 which is disposed so as to face the first electrode 11 across a gap; and an intermediate part which is provided within the gap. The intermediate part includes nanoparticles 14. The nanoparticles 14 have a work function that falls between the work function of the first electrode 11 and the work function of the second electrode 12. The first electrode 11 and the second electrode 12 are both made of the same conductive material, and the second electrode 12 is subjected to annealing so as to change the work function φA of the second electrode 12 from the level of the work function φK of the first electrode 11 to a level that exceeds the work function φN of the nanoparticles 14.

Description

電極の仕事関数の制御方法、発電素子及び発電素子の製造方法Electrode work function control method, power generation element and manufacturing method of power generation element
　この発明の実施形態は、電極の仕事関数の制御方法、発電素子及び発電素子の製造方法に関する。 An embodiment of the present invention relates to a method of controlling a work function of electrodes, a power generation element, and a method of manufacturing a power generation element.
　近年、熱エネルギーを利用して電気エネルギーを生成する熱電素子等の発電素子の開発が盛んに行われている。特許文献１及び２には、仕事関数差を有する電極間に発生する、絶対温度による電子放出現象を利用した熱電素子が開示されている。このような熱電素子は、電極間の温度差（ゼーベック効果）を利用した熱電素子に比較して、電極間の温度差が小さい場合であっても発電可能である。このため、より様々な用途への利用が期待されている。 In recent years, the development of power generation elements such as thermoelectric elements that generate electric energy using thermal energy has been actively carried out. Patent Documents 1 and 2 disclose thermoelectric elements that utilize an electron emission phenomenon due to absolute temperature that occurs between electrodes having a work function difference. Such a thermoelectric element can generate electricity even when the temperature difference between the electrodes is small as compared with the thermoelectric element using the temperature difference between the electrodes (Seebeck effect). Therefore, it is expected to be used for various purposes.
　特許文献１には、エミッタ電極層と、コレクタ電極層と、エミッタ電極層及びコレクタ電極層の表面に分散して配置され、エミッタ電極層とコレクタ電極層とをサブミクロン間隔で離間する電気絶縁性の球状ナノビーズとを備え、エミッタ電極層の仕事関数はコレクタ電極層の仕事関数よりも小さく、球状ナノビーズの粒子径は１００ｎｍ以下である熱電素子が開示されている。 In Patent Document 1, the emitter electrode layer, the collector electrode layer, the emitter electrode layer, and the collector electrode layer are dispersedly arranged on the surface, and the emitter electrode layer and the collector electrode layer are separated from each other at submicron intervals. A thermoelectric element is disclosed that comprises the spherical nanobeads, the work function of the emitter electrode layer is smaller than the work function of the collector electrode layer, and the particle size of the spherical nanobeads is 100 nm or less.
　特許文献２には、ナノメートルスケールの間隔を空けた電極間ギャップによって分離された、仕事関数の高いアノードと、仕事関数の低いカソードとを備え、電極間ギャップにナノ流体が形成されるナノ流体接触電位差セルが開示されている。 Patent Document 2 includes a nanofluid having a high work function anode and a low work function cathode separated by nanometer-scale spaced electrode-to-electrode gaps, in which nanofluids are formed in the inter-electrode gaps. Contact potential difference cells are disclosed.
特許第６１４７９０１号公報Japanese Patent No. 6147901 米国特許出願公開第２０１５／０２２９０１３号明細書U.S. Patent Application Publication No. 2015/0229013
　特許文献１に開示された熱電素子（発電素子）及び特許文献２に開示されたナノ流体接触電位差セル（発電素子）では、仕事関数がそれぞれ異なった２つの電極が必要であり、そして、２つの電極のそれぞれには、異なった導電性物質が使用される。 The thermoelectric element (power generation element) disclosed in Patent Document 1 and the nanofluid contact potential difference cell (power generation element) disclosed in Patent Document 2 require two electrodes having different work functions, and two electrodes. Different conductive materials are used for each of the electrodes.
　特許文献１及び２では異なった導電性物質を使用するために、例えば、以下のような事情を生じる。
　・異なった導電性物質ごとに、原料を購入する必要がある。
　・異なった導電性物質ごとに、高価な成膜装置又は高価な製造ラインを用意する必要がある。
したがって、特許文献１及び２では、発電素子の製造コストが増大する。 In Patent Documents 1 and 2, in order to use different conductive substances, for example, the following circumstances occur.
-It is necessary to purchase raw materials for different conductive substances.
-It is necessary to prepare an expensive film forming apparatus or an expensive production line for each different conductive substance.
Therefore, in Patent Documents 1 and 2, the manufacturing cost of the power generation element increases.
　この発明の実施形態は、発電素子の製造コストを抑制することが可能な電極の仕事関数の制御方法、発電素子及び発電素子の製造方法を提供する。 An embodiment of the present invention provides a method for controlling a work function of electrodes and a method for manufacturing a power generation element and a power generation element, which can suppress the manufacturing cost of the power generation element.
　この発明の第１態様に係る電極の仕事関数の制御方法は、熱エネルギーを電気エネルギーに変換する発電素子の電極の仕事関数の制御方法であって、前記発電素子は、第１電極と、第１電極とギャップを介して対向した第２電極と、前記ギャップ内に設けられた、前記第１電極の仕事関数と前記第２電極の仕事関数との間の仕事関数を有するナノ粒子を含む中間部と、を有し、前記第１電極及び前記第２電極のそれぞれは、同じ導電性物質であり、前記第２電極をアニールし、前記第２電極の仕事関数の値を、前記第１電極の仕事関数の値から、前記ナノ粒子の仕事関数の値を超えて変化させることを特徴とする。 The method of controlling the work function of the electrode according to the first aspect of the present invention is a method of controlling the work function of the electrode of the power generation element that converts thermal energy into electrical energy, and the power generation element includes the first electrode and the first electrode. An intermediate containing a second electrode facing the first electrode via a gap and nanoparticles provided in the gap and having a work function between the work function of the first electrode and the work function of the second electrode. Each of the first electrode and the second electrode is the same conductive material, the second electrode is annealed, and the value of the work function of the second electrode is set to the first electrode. It is characterized in that the value of the work function of the nanoparticle is changed beyond the value of the work function of the nanoparticles.
　この発明の第２態様に係る電極の仕事関数の制御方法は、第１態様において、前記アニールは、酸化性雰囲気中で行い、前記第２電極の少なくとも前記第１電極と対向する面を、酸化することを特徴とする。 The method for controlling the work function of the electrode according to the second aspect of the present invention is that in the first aspect, the annealing is performed in an oxidizing atmosphere, and at least the surface of the second electrode facing the first electrode is oxidized. It is characterized by doing.
　この発明の第３態様に係る電極の仕事関数の制御方法は、第１態様において、前記第１電極の少なくとも前記第２電極と対向する面上には、前記導電性物質の第１酸化被膜が有り、前記第２電極の少なくとも前記第１電極と対向する面上には、前記導電性物質の第２酸化被膜が有り、前記アニールは、酸化性雰囲気中で行い、前記アニールにより、
　（１）前記第２酸化被膜の酸化数を、前記第１酸化被膜の酸化数よりも増加させること
　（２）前記第２酸化被膜の厚さを、前記第１酸化被膜の厚さよりも厚くすること
　（３）前記第２酸化被膜を、前記第１酸化被膜から同素変態させること
　前記（１）～（３）の少なくとも１つを行うことを特徴とする。 In the method of controlling the work function of the electrode according to the third aspect of the present invention, in the first aspect, the first oxide film of the conductive substance is formed on at least the surface of the first electrode facing the second electrode. Yes, there is a second oxide film of the conductive substance on at least the surface of the second electrode facing the first electrode, and the annealing is performed in an oxidizing atmosphere, and the annealing is performed by the annealing.
(1) Increase the oxidation number of the second oxide film from the oxidation number of the first oxide film (2) Make the thickness of the second oxide film thicker than the thickness of the first oxide film. (3) Passivation of the second oxide film from the first oxide film is characterized by performing at least one of the above (1) to (3).
　この発明の第４態様に係る電極の仕事関数の制御方法は、第３態様において、前記酸化性雰囲気は、大気であることを特徴とする。 The method for controlling the work function of the electrode according to the fourth aspect of the present invention is characterized in that, in the third aspect, the oxidizing atmosphere is the atmosphere.
　この発明の第５態様に係る電極の仕事関数の制御方法は、第１態様において、前記アニールは、還元性雰囲気中で行い、前記第２電極の少なくとも前記第１電極と対向する面を、還元することを特徴とする。 The method for controlling the work function of the electrode according to the fifth aspect of the present invention is that in the first aspect, the annealing is performed in a reducing atmosphere, and at least the surface of the second electrode facing the first electrode is reduced. It is characterized by doing.
　この発明の第６態様に係る電極の仕事関数の制御方法は、第１態様において、前記第１電極の少なくとも前記第２電極と対向する面上には、前記導電性物質の第１酸化被膜が有り、前記第２電極の少なくとも前記第１電極と対向する面上には、前記導電性物質の第２酸化被膜が有り、前記アニールは、還元性雰囲気中で行い、前記アニールにより、
　（４）前記第２酸化被膜の酸化数を、前記第１酸化被膜の酸化数よりも減少させる
　（５）前記第２酸化被膜の厚さを、前記第１酸化被膜の厚さよりも薄くする
　（６）前記第２酸化被膜を、前記第１酸化被膜から同素変態させる
　前記（４）～（６）の少なくとも１つを行うことを特徴とする。 In the method of controlling the work function of the electrode according to the sixth aspect of the present invention, in the first aspect, the first oxide film of the conductive substance is formed on at least the surface of the first electrode facing the second electrode. Yes, there is a second oxide film of the conductive substance on at least the surface of the second electrode facing the first electrode, and the annealing is performed in a reducing atmosphere, and the annealing is performed by the annealing.
(4) Decrease the oxidation number of the second oxide film from the oxidation number of the first oxide film (5) Make the thickness of the second oxide film thinner than the thickness of the first oxide film (5) 6) It is characterized in that at least one of the above (4) to (6) is performed to passivate the second oxide film from the first oxide film.
　この発明の第７態様に係る電極の仕事関数の制御方法は、第３態様～第６態様のいずれか１つにおいて、前記第１酸化被膜及び前記アニールされる前の第２酸化被膜のそれぞれは、前記導電性物質の自然酸化被膜であることを特徴とする。 The method for controlling the work function of the electrode according to the seventh aspect of the present invention is that in any one of the third to sixth aspects, each of the first oxide film and the second oxide film before being annealed , It is a natural oxide film of the conductive substance.
　この発明の第８態様に係る電極の仕事関数の制御方法は、第１態様において、前記アニールは、減圧下又は不活性雰囲気中で行い、前記第２電極を、前記第１電極から同素変態させることを特徴とする。 The method for controlling the work function of the electrode according to the eighth aspect of the present invention is that in the first aspect, the annealing is performed under reduced pressure or in an inert atmosphere, and the second electrode is allotropically transformed from the first electrode. It is characterized by letting it.
　この発明の第９態様に係る電極の仕事関数の制御方法は、第１態様において、前記アニールは、活性雰囲気中で行い、前記第２電極の少なくとも前記第１電極と対向する面を、表面改質することを特徴とする。 In the first aspect of the method for controlling the work function of the electrode according to the ninth aspect of the present invention, the annealing is performed in an active atmosphere, and at least the surface of the second electrode facing the first electrode is surface-modified. It is characterized by quality.
　この発明の第１０態様に係る電極の仕事関数の制御方法は、第１態様～第９態様のいずれか１つにおいて、前記導電性物質は、第４族元素を含むことを特徴とする。 The method for controlling the work function of the electrode according to the tenth aspect of the present invention is characterized in that, in any one of the first to ninth aspects, the conductive substance contains a Group 4 element.
　この発明の第１１態様に係る電極の仕事関数の制御方法は、第１態様～第１０態様のいずれか１つにおいて、前記第１電極はアニールしないこと、前記第１電極のアニール温度は前記第２電極よりも低いこと、前記第１電極のアニール時間は前記第２電極よりも短いこと又は前記第１電極のアニールエネルギーは前記第２電極よりも低いことを特徴とする。 The method for controlling the work function of the electrode according to the eleventh aspect of the present invention is that the first electrode is not annealed in any one of the first to tenth aspects, and the annealing temperature of the first electrode is the first. It is characterized in that it is lower than the two electrodes, the annealing time of the first electrode is shorter than that of the second electrode, or the annealing energy of the first electrode is lower than that of the second electrode.
　この発明の第１２態様に係る電極の仕事関数の制御方法は、第１態様～第１１態様のいずれか１つにおいて、前記アニールは、熱アニール、レーザアニール及び光アニールの少なくとも１つを含むことを特徴とする。 The method for controlling the work function of the electrode according to the twelfth aspect of the present invention is any one of the first to eleventh aspects, wherein the annealing includes at least one of thermal annealing, laser annealing and optical annealing. It is characterized by.
　この発明の第１３態様に係る発電素子は、第１電極と、第１電極とギャップを介して対向した第２電極と、前記ギャップ内に設けられた、前記第１電極の仕事関数と前記第２電極の仕事関数との間の仕事関数を有するナノ粒子を含む中間部と、を有し、前記第１電極及び前記第２電極のそれぞれは、同じ導電性物質であり、前記第２電極の少なくとも前記第１電極と対向する面の状態は、前記第１電極の少なくとも前記第２電極と対向する面の状態と異なることを特徴とする。 The power generation element according to the thirteenth aspect of the present invention includes a first electrode, a second electrode facing the first electrode via a gap, a work function of the first electrode provided in the gap, and the first electrode. It has an intermediate portion containing nanoparticles having a work function between the two electrodes, and each of the first electrode and the second electrode is the same conductive material, and the second electrode has. At least the state of the surface facing the first electrode is different from the state of the surface of the first electrode facing at least the second electrode.
　この発明の第１４態様に係る発電素子は、第１３態様において、前記第２電極の少なくとも前記第１電極と対向する面は、酸化されていることを特徴とする。 The power generation element according to the 14th aspect of the present invention is characterized in that, in the 13th aspect, at least the surface of the second electrode facing the first electrode is oxidized.
　この発明の第１５態様に係る発電素子は、第１３態様において、前記第２電極の少なくとも前記第１電極と対向する面は、還元されていることを特徴とする。 The power generation element according to the fifteenth aspect of the present invention is characterized in that, in the thirteenth aspect, at least the surface of the second electrode facing the first electrode is reduced.
　この発明の第１６態様に係る発電素子は、第１３態様において、前記第１電極の少なくとも前記第２電極と対向する面上には、前記導電性物質の第１酸化被膜が有り、前記第２電極の少なくとも前記第１電極と対向する面上には、前記導電性物質の第２酸化被膜が有り、前記第２酸化被膜は、
　（７）前記第２酸化被膜の酸化数は、前記第１酸化被膜の酸化数よりも大きい
　（８）前記第２酸化被膜の厚さは、前記第１酸化被膜の厚さよりも厚い
　（９）前記第２酸化被膜は、前記第１酸化被膜の同素変態物を含む
　前記（７）～（９）に記載された少なくとも１つの状態を取ることを特徴とする。 In the thirteenth aspect, the power generation element according to the sixteenth aspect of the present invention has a first oxide film of the conductive substance on at least the surface of the first electrode facing the second electrode, and the second electrode. At least on the surface of the electrode facing the first electrode, there is a second oxide film of the conductive substance, and the second oxide film is formed on the second oxide film.
(7) The oxidation number of the second oxide film is larger than the oxidation number of the first oxide film. (8) The thickness of the second oxide film is thicker than the thickness of the first oxide film (9). The second oxide film is characterized by taking at least one of the states described in (7) to (9) above, which contains a homogenous variant of the first oxide film.
　この発明の第１７態様に係る発電素子は、第１３態様において、前記第２電極は、前記第１電極の同素変態物を含むことを特徴とする。 The power generation element according to the 17th aspect of the present invention is characterized in that, in the 13th aspect, the second electrode contains an allotropic transformation of the first electrode.
　この発明の第１８態様に係る発電素子は、第１３態様において、前記第２電極の少なくとも前記第１電極と対向する面は、表面改質されていることを特徴とする。 The power generation element according to the eighteenth aspect of the present invention is characterized in that, in the thirteenth aspect, at least the surface of the second electrode facing the first electrode is surface-modified.
　この発明の第１９態様に係る発電素子は、第１３態様～第１８態様のいずれか１つにおいて、前記導電性物質は、第４族元素を含むことを特徴とする。 The power generation element according to the 19th aspect of the present invention is characterized in that, in any one of the 13th to 18th aspects, the conductive substance contains a Group 4 element.
　この発明の第２０態様に係る発電素子の製造方法は、第１基板上に、第１電極を形成する工程と、第２基板上に、前記第１電極と同じ導電性物質である第２電極を形成する工程と、前記第２電極をアニールし、前記第２電極の仕事関数を、前記第１電極の仕事関数から変化させる工程と、前記第１電極と前記第２電極とを、ギャップを介して対向させる工程と、前記第１電極の仕事関数と前記第２電極の前記変化された仕事関数との間の仕事関数を有するナノ粒子を、前記ギャップ内に導入する工程と、を備えたことを特徴とする。 The method for manufacturing a power generation element according to a twentieth aspect of the present invention includes a step of forming a first electrode on a first substrate and a second electrode on the second substrate, which is the same conductive material as the first electrode. The step of forming the second electrode, the step of changing the work function of the second electrode from the work function of the first electrode, and the gap between the first electrode and the second electrode. It comprises a step of facing each other through the gap and a step of introducing nanoparticles having a work function between the work function of the first electrode and the changed work function of the second electrode into the gap. It is characterized by that.
　第１態様に係る電極の仕事関数の制御方法によれば、第１電極及び第２電極のそれぞれを、同じ導電性物質とする。そして、第２電極をアニールすることで、第２電極の仕事関数の値を、第１電極の仕事関数の値から、ナノ粒子の仕事関数の値を超えて変化させる。これにより、仕事関数がそれぞれ異なった第１電極及び第２電極を、１つの導電性物質から得ることができる。第１電極及び第２電極は、１つの導電性物質から得ることができるので、第１電極及び第２電極それぞれの原料を共通化することができる。したがって、発電素子の製造コストを抑制することが可能な電極の仕事関数の制御方法が得られる。また、第１電極及び第２電極の原料を共通化できるので、例えば、第１電極及び第２電極のそれぞれを同じ成膜装置又は同じ製造ラインで形成することができる。第１電極及び第２電極のそれぞれを同じ成膜装置又は同じ製造ラインで形成すると、発電素子の製造コストを、更に抑えることができる。 According to the method for controlling the work function of the electrodes according to the first aspect, each of the first electrode and the second electrode is made of the same conductive substance. Then, by annealing the second electrode, the value of the work function of the second electrode is changed from the value of the work function of the first electrode beyond the value of the work function of the nanoparticles. Thereby, the first electrode and the second electrode having different work functions can be obtained from one conductive substance. Since the first electrode and the second electrode can be obtained from one conductive substance, the raw materials of the first electrode and the second electrode can be shared. Therefore, a method of controlling the work function of the electrode, which can suppress the manufacturing cost of the power generation element, can be obtained. Further, since the raw materials of the first electrode and the second electrode can be shared, for example, each of the first electrode and the second electrode can be formed by the same film forming apparatus or the same production line. If each of the first electrode and the second electrode is formed by the same film forming apparatus or the same production line, the production cost of the power generation element can be further suppressed.
　第２態様に係る電極の仕事関数の制御方法によれば、アニールは酸化性雰囲気中で行い、第２電極の少なくとも第１電極と対向する面を酸化する。これにより、例えば、第１電極の第２電極と対向する面上には酸化物が無く、第２電極の第１電極と対向する面上には酸化物が有る状態が得られる。例えば、対向する面における酸化物の有無によって、第２電極の仕事関数の値を、第１電極の仕事関数の値から、ナノ粒子の仕事関数の値を超えて変化させることができる。 According to the method for controlling the work function of the electrode according to the second aspect, annealing is performed in an oxidizing atmosphere, and at least the surface of the second electrode facing the first electrode is oxidized. As a result, for example, it is possible to obtain a state in which there is no oxide on the surface of the first electrode facing the second electrode and there is an oxide on the surface of the second electrode facing the first electrode. For example, the value of the work function of the second electrode can be changed from the value of the work function of the first electrode beyond the value of the work function of the nanoparticles depending on the presence or absence of oxides on the opposing surfaces.
　第３態様に係る電極の仕事関数の制御方法によれば、アニールは酸化性雰囲気中で行い、アニールにより、
　（１）第２酸化被膜の酸化数を、第１酸化被膜の酸化数よりも増加させること
　（２）第２酸化被膜の厚さを、第１酸化被膜の厚さよりも厚くすること
　（３）第２酸化被膜を、第１酸化被膜から同素変態させること
の少なくとも１つを行う。例えば、上記（１）～（３）の少なくとも１つを行うことによって、第２電極の仕事関数の値を、第１電極の仕事関数の値から、ナノ粒子の仕事関数の値を超えて変化させることができる。 According to the method for controlling the work function of the electrode according to the third aspect, the annealing is performed in an oxidizing atmosphere, and the annealing is performed by annealing.
(1) Increase the oxidation number of the second oxide film from the oxidation number of the first oxide film (2) Make the thickness of the second oxide film thicker than the thickness of the first oxide film (3) At least one of the passivation transformations of the second oxide film from the first oxide film is performed. For example, by performing at least one of the above (1) to (3), the value of the work function of the second electrode is changed from the value of the work function of the first electrode beyond the value of the work function of the nanoparticles. Can be made to.
　第４態様に係る電極の仕事関数の制御方法によれば、酸化性雰囲気を大気とするので、第２電極の少なくとも第１電極と対向する面の酸化を、より安価に行うことができる。したがって、発電素子の製造コストを、更に抑えることができる。 According to the method for controlling the work function of the electrode according to the fourth aspect, since the oxidizing atmosphere is the atmosphere, oxidation of at least the surface of the second electrode facing the first electrode can be performed at a lower cost. Therefore, the manufacturing cost of the power generation element can be further suppressed.
　第５態様に係る電極の仕事関数の制御方法によれば、アニールは還元性雰囲気中で行い、第２電極の少なくとも第１電極と対向する面を還元する。これにより、例えば、第１電極の第２電極と対向する面上には酸化物が有り、第２電極の第１電極と対向する面上には酸化物が無い状態が得られる。例えば、対向する面における酸化物の有無によって、第２電極の仕事関数の値を、第１電極の仕事関数の値から、ナノ粒子の仕事関数の値を超えて変化させることができる。 According to the method for controlling the work function of the electrode according to the fifth aspect, annealing is performed in a reducing atmosphere, and at least the surface of the second electrode facing the first electrode is reduced. As a result, for example, a state in which the oxide is present on the surface of the first electrode facing the second electrode and no oxide is present on the surface of the second electrode facing the first electrode can be obtained. For example, the value of the work function of the second electrode can be changed from the value of the work function of the first electrode beyond the value of the work function of the nanoparticles depending on the presence or absence of oxides on the opposing surfaces.
　第６態様に係る電極の仕事関数の制御方法によれば、アニールは還元性雰囲気中で行い、アニールにより、
　（４）第２酸化被膜の酸化数を、第１酸化被膜の酸化数よりも減少させること
　（５）第２酸化被膜の厚さを、第１酸化被膜の厚さよりも薄くすること
　（６）第２酸化被膜を、第１酸化被膜から同素変態させること
の少なくとも１つを行う。例えば、上記（４）～（６）の少なくとも１つを行うことによって、第２電極の仕事関数の値を、第１電極の仕事関数の値から、ナノ粒子の仕事関数の値を超えて変化させることができる。 According to the method for controlling the work function of the electrode according to the sixth aspect, the annealing is performed in a reducing atmosphere, and the annealing is performed by annealing.
(4) Decrease the oxidation number of the second oxide film from the oxidation number of the first oxide film (5) Make the thickness of the second oxide film thinner than the thickness of the first oxide film (6) At least one of the passivation transformations of the second oxide film from the first oxide film is performed. For example, by performing at least one of the above (4) to (6), the value of the work function of the second electrode is changed from the value of the work function of the first electrode beyond the value of the work function of the nanoparticles. Can be made to.
　第７態様に係る電極の仕事関数の制御方法によれば、第１酸化被膜及びアニールされる前の第２酸化被膜のそれぞれは、導電性物質の自然酸化被膜である。そして、アニールは、自然酸化被膜である第２酸化被膜に対して酸化性雰囲気で行われる。アニールされた第２酸化被膜では、例えば酸化数が増加し、第２酸化被膜の膜質が第１酸化被膜の膜質よりも、例えば緻密になる。これにより、例えば、自然酸化被膜であった第２酸化被膜のフェルミ準位は、自然酸化被膜のままである第１酸化被膜のフェルミ準位から変えることができる。例えば、第１酸化被膜のフェルミ準位と第２酸化被膜のフェルミ準位との違いによって、第２電極の仕事関数の値を、第１電極の仕事関数の値から、ナノ粒子の仕事関数の値を超えて変化させることができる。 According to the method for controlling the work function of the electrode according to the seventh aspect, each of the first oxide film and the second oxide film before being annealed is a natural oxide film of a conductive substance. Then, annealing is performed in an oxidizing atmosphere with respect to the second oxide film which is a natural oxide film. In the annealed second oxide film, for example, the oxidation number increases, and the film quality of the second oxide film becomes denser, for example, than the film quality of the first oxide film. Thereby, for example, the Fermi level of the second oxide film which was a natural oxide film can be changed from the Fermi level of the first oxide film which is still a natural oxide film. For example, depending on the difference between the Fermi level of the first oxide film and the Fermi level of the second oxide film, the work function value of the second electrode is calculated from the work function value of the first electrode, and the work function of the nanoparticles is calculated. It can be changed beyond the value.
　第８態様に係る電極の仕事関数の制御方法によれば、アニールを減圧下又は不活性雰囲気中で行い、第２電極を第１電極から同素変態させる。第２電極を第１電極から同素変態させることで、第２電極の仕事関数の値を、第１電極の仕事関数の値から、ナノ粒子の仕事関数の値を超えて変化させることができる。 According to the method for controlling the work function of the electrode according to the eighth aspect, annealing is performed under reduced pressure or in an inert atmosphere, and the second electrode is allotropically transformed from the first electrode. By allotropically transforming the second electrode from the first electrode, the value of the work function of the second electrode can be changed from the value of the work function of the first electrode beyond the value of the work function of the nanoparticles. ..
　第９態様に係る電極の仕事関数の制御方法によれば、アニールを活性雰囲気中で行い、第２電極の少なくとも第１電極と対向する面を、表面改質する。第２電極の少なくとも第１電極と対向する面を表面改質することで、第２電極の仕事関数の値を、第１電極の仕事関数の値から、ナノ粒子の仕事関数の値を超えて変化させることができる。 According to the method for controlling the work function of the electrode according to the ninth aspect, annealing is performed in an active atmosphere, and at least the surface of the second electrode facing the first electrode is surface-modified. By surface-modifying at least the surface of the second electrode facing the first electrode, the value of the work function of the second electrode exceeds the value of the work function of the nanoparticles from the value of the work function of the first electrode. Can be changed.
　第１０態様に係る電極の仕事関数の制御方法によれば、導電性物質が第４族元素を含む。第４族元素は融点が高く、熱膨張率及びヤング率も比較的小さい。このため、アニールに耐えやすい導電性物質である。また、第４族元素は入手しやすい。第４族元素の中でも、例えばチタンは入手しやすく、かつ、安価である。第４族元素は、第１態様～第１０態様のいずれか１つに係る電極の仕事関数の制御方法の実施に有用な導電性物質の１つである。 According to the method for controlling the work function of the electrode according to the tenth aspect, the conductive substance contains a Group 4 element. Group 4 elements have a high melting point and a relatively small coefficient of thermal expansion and Young's modulus. Therefore, it is a conductive substance that can easily withstand annealing. In addition, Group 4 elements are easily available. Among the Group 4 elements, for example, titanium is easily available and inexpensive. The Group 4 element is one of the conductive substances useful for carrying out the method for controlling the work function of the electrode according to any one of the first to tenth aspects.
　第１１態様に係る電極の仕事関数の制御方法によれば、第１電極はアニールしない。これにより、第１電極の仕事関数の値と第２電極の仕事関数の値との差を、より大きくできる。また、第１電極はアニールしても良い。ただし、第１電極をアニールした場合には、第１電極のアニール温度を第２電極よりも低くすること、第１電極のアニール時間を第２電極よりも短くすること又は第１電極のアニールエネルギーを第２電極よりも低くすることで、第１電極の仕事関数の値と第２電極の仕事関数の値との差を、大きく保つことができる。 According to the method for controlling the work function of the electrode according to the eleventh aspect, the first electrode is not annealed. Thereby, the difference between the value of the work function of the first electrode and the value of the work function of the second electrode can be made larger. Further, the first electrode may be annealed. However, when the first electrode is annealed, the annealing temperature of the first electrode should be lower than that of the second electrode, the annealing time of the first electrode should be shorter than that of the second electrode, or the annealing energy of the first electrode should be set. By making the value lower than that of the second electrode, the difference between the value of the work function of the first electrode and the value of the work function of the second electrode can be kept large.
　第１２態様に係る電極の仕事関数の制御方法によれば、アニールは、熱アニール、レーザアニール及び光アニールの少なくとも１つを含む。第１態様～第１１態様のいずれか１つに係る電極の仕事関数の制御方法では、アニール方法として、熱アニール、レーザアニール及び光アニールの少なくとも１つを選ぶことができる。 According to the method for controlling the work function of the electrode according to the twelfth aspect, the annealing includes at least one of thermal annealing, laser annealing and optical annealing. In the method for controlling the work function of the electrode according to any one of the first to eleventh aspects, at least one of thermal annealing, laser annealing, and optical annealing can be selected as the annealing method.
　第１３態様に係る発電素子によれば、第１電極及び第２電極のそれぞれは同じ導電性物質であり、第２電極の少なくとも第１電極と対向する面の状態は、第１電極の少なくとも第２電極と対向する面の状態と異なる。対向する面の状態が異なることによって、第１電極及び第２電極のそれぞれが同じ導電性物質でありながらも、第１電極の仕事関数の値φ１、第２電極の仕事関数の値φ２及びナノ粒子の仕事関数の値φＮの関係を、
　　φ１　＜　φＮ　＜　φ２
とすることができる。 According to the power generation element according to the thirteenth aspect, each of the first electrode and the second electrode is the same conductive substance, and the state of the surface of the second electrode facing at least the first electrode is at least the first of the first electrodes. It is different from the state of the surface facing the two electrodes. Due to the different states of the facing surfaces, the work function value of the first electrode is φ1, the work function value of the second electrode is φ2, and the nano is nano, even though the first electrode and the second electrode are the same conductive substance. The relationship of the value φN of the work function of the particle,
φ1 <φN <φ2
Can be.
　第１４態様に係る発電素子によれば、第２電極の少なくとも第１電極と対向する面は、酸化されている。これにより、例えば、第１電極の第２電極と対向する面上には酸化物が無く、第２電極の第１電極と対向する面上には酸化物が有る状態を得ることができる。例えば、対向する面における酸化物の有無によって、第１電極及び第２電極のそれぞれが同じ導電性物質でありながらも、第１電極の仕事関数の値φ１、第２電極の仕事関数の値φ２及びナノ粒子の仕事関数の値φＮの関係を、
　　φ１　＜　φＮ　＜　φ２
とすることができる。 According to the power generation element according to the fourteenth aspect, at least the surface of the second electrode facing the first electrode is oxidized. Thereby, for example, it is possible to obtain a state in which there is no oxide on the surface of the first electrode facing the second electrode and there is an oxide on the surface of the second electrode facing the first electrode. For example, depending on the presence or absence of oxides on the opposing surfaces, the work function value of the first electrode is φ1 and the work function value of the second electrode is φ2, even though the first electrode and the second electrode are the same conductive substance. And the relationship of the work function value φN of the nanoparticles,
φ1 <φN <φ2
Can be.
　第１５態様に係る発電素子によれば、第２電極の少なくとも第１電極と対向する面は、還元されている。これにより、例えば、第１電極の第２電極と対向する面上には酸化物が有り、第２電極の第１電極と対向する面上には酸化物が無い状態を得ることができる。例えば、対向する面における酸化物の有無によって、第１電極及び第２電極のそれぞれが同じ導電性物質でありながらも、第１電極の仕事関数の値φ１、第２電極の仕事関数の値φ２及びナノ粒子の仕事関数の値φＮの関係を、
　　φ１　＜　φＮ　＜　φ２
とすることができる。 According to the power generation element according to the fifteenth aspect, at least the surface of the second electrode facing the first electrode is reduced. Thereby, for example, it is possible to obtain a state in which an oxide is present on the surface of the first electrode facing the second electrode and no oxide is present on the surface of the second electrode facing the first electrode. For example, depending on the presence or absence of oxides on the opposing surfaces, the work function value of the first electrode is φ1 and the work function value of the second electrode is φ2, even though the first electrode and the second electrode are the same conductive substance. And the relationship of the work function value φN of the nanoparticles,
φ1 <φN <φ2
Can be.
　第１６態様に係る発電素子によれば、第１電極及び第２電極のそれぞれは同じ導電性物質であり、第１電極のギャップに面した表面上には、導電性物質の第１酸化被膜があり、第２電極のギャップに面した表面上には、導電性物質の第２酸化被膜がある。第２酸化被膜は、
　（７）第２酸化被膜の酸化数は、第１酸化被膜の酸化数よりも大きい
　（８）第２酸化被膜の厚さは、第１酸化被膜の厚さよりも厚い
　（９）第２酸化被膜は、第１酸化被膜の同素変態物を含む
の少なくとも１つの状態を取る。例えば、第２酸化被膜が上記（７）～（９）の少なくとも１つの状態を取ることによって、第１電極及び第２電極のそれぞれが同じ導電性物質でありながらも、第１電極の仕事関数の値φ１、第２電極の仕事関数の値φ２及びナノ粒子の仕事関数の値φＮの関係を、
　　φ１　＜　φＮ　＜　φ２
とすることができる。 According to the power generation element according to the 16th aspect, each of the first electrode and the second electrode is the same conductive substance, and a first oxide film of the conductive substance is formed on the surface of the first electrode facing the gap. There is a second oxide film of conductive material on the surface facing the gap of the second electrode. The second oxide film is
(7) The oxidation number of the second oxide film is larger than the oxidation number of the first oxide film (8) The thickness of the second oxide film is thicker than the thickness of the first oxide film (9) The second oxide film Takes at least one state, including a homogenous variant of the first oxide film. For example, when the second oxide film takes at least one of the above states (7) to (9), the work function of the first electrode is obtained even though each of the first electrode and the second electrode is the same conductive substance. The relationship between the value φ1 of, the work function value φ2 of the second electrode, and the work function value φN of the nanoparticles,
φ1 <φN <φ2
Can be.
　第１７態様に係る発電素子によれば、第２電極は、第１電極の同素変態物を含む。例えば、第２電極が第１電極の同素変態物を含むことによって、第１電極及び第２電極のそれぞれが同じ導電性物質でありながらも、第１電極の仕事関数の値φ１、第２電極の仕事関数の値φ２及びナノ粒子の仕事関数の値φＮの関係を、
　　φ１　＜　φＮ　＜　φ２
とすることができる。 According to the power generation element according to the seventeenth aspect, the second electrode contains an allotropic transformation of the first electrode. For example, since the second electrode contains a homogenous transformation of the first electrode, the work function values of the first electrode φ1 and the second electrode are the same even though the first electrode and the second electrode are the same conductive material, respectively. The relationship between the work function value φ2 of the electrode and the work function value φN of the nanoparticles,
φ1 <φN <φ2
Can be.
　第１８態様に係る発電素子によれば、第２電極の少なくとも第１電極と対向する面は、表面改質されている。例えば、第２電極の少なくとも第１電極と対向する面が表面改質されていることによって、第１電極及び第２電極のそれぞれが同じ導電性物質でありながらも、第１電極の仕事関数の値φ１、第２電極の仕事関数の値φ２及びナノ粒子の仕事関数の値φＮの関係を、
　　φ１　＜　φＮ　＜　φ２
とすることができる。 According to the power generation element according to the eighteenth aspect, at least the surface of the second electrode facing the first electrode is surface-modified. For example, by surface-modifying at least the surface of the second electrode facing the first electrode, the work function of the first electrode is different even though the first electrode and the second electrode are each the same conductive material. The relationship between the value φ1, the work function value φ2 of the second electrode, and the work function value φN of the nanoparticles,
φ1 <φN <φ2
Can be.
　第１９態様に係る発電素子によれば、導電性物質は、第４族元素を含む。第４族元素は融点が高く、熱膨張率及びヤング率も比較的小さい。このため、アニールに耐えやすい導電性物質である。また、第４族元素は入手しやすい。第４族元素の中でも、例えばチタンは入手しやすく、かつ、安価である。第４族元素は、第１３態様～第１８態様のいずれか１つに係る発電素子の実施に有用な導電性物質の１つである。 According to the power generation element according to the 19th aspect, the conductive substance contains a Group 4 element. Group 4 elements have a high melting point and a relatively small coefficient of thermal expansion and Young's modulus. Therefore, it is a conductive substance that can easily withstand annealing. In addition, Group 4 elements are easily available. Among the Group 4 elements, for example, titanium is easily available and inexpensive. The Group 4 element is one of the conductive substances useful for carrying out the power generation element according to any one of the thirteenth to eighteenth aspects.
　第２０態様に係る発電素子の製造方法によれば、第１基板上に第１電極を形成し、第２基板上に第１電極と同じ導電性物質である第２電極を形成し、第２電極をアニールして第２電極の仕事関数を第１電極の仕事関数から変化させる。さらに、第１電極と第２電極とをギャップを介して対向させ、第１電極の仕事関数と第２電極の変化された仕事関数との間の仕事関数を有するナノ粒子をギャップ内に充填する。これにより、第２電極に第１電極と同じ導電性物質を用いつつも、第２電極の仕事関数を第１電極の仕事関数から変化させることができる。したがって、発電素子の製造コストを抑制することが可能な発電素子の製造方法を得ることができる。 According to the method for manufacturing a power generation element according to the twentieth aspect, the first electrode is formed on the first substrate, the second electrode which is the same conductive material as the first electrode is formed on the second substrate, and the second electrode is formed. The electrode is annealed to change the work function of the second electrode from the work function of the first electrode. Further, the first electrode and the second electrode are opposed to each other through the gap, and nanoparticles having a work function between the work function of the first electrode and the changed work function of the second electrode are filled in the gap. .. As a result, the work function of the second electrode can be changed from the work function of the first electrode while using the same conductive substance as the first electrode for the second electrode. Therefore, it is possible to obtain a method for manufacturing a power generation element that can suppress the manufacturing cost of the power generation element.
図１（ａ）は、この発明の第１実施形態に係る発電素子の一例を示す模式断面図である。図１（ｂ）は、この発明の第１実施形態に係る発電素子を用いた発電装置の一例を示す模式断面図である。FIG. 1A is a schematic cross-sectional view showing an example of a power generation element according to the first embodiment of the present invention. FIG. 1B is a schematic cross-sectional view showing an example of a power generation device using a power generation element according to the first embodiment of the present invention. 図２（ａ）は中間部の一例を示す模式断面図、図２（ｂ）は中間部の他の例を示す模式断面図である。FIG. 2A is a schematic cross-sectional view showing an example of the intermediate portion, and FIG. 2B is a schematic cross-sectional view showing another example of the intermediate portion. 図３は、第１電極、第２電極及びナノ粒子の仕事関数の関係を示す図である。FIG. 3 is a diagram showing the relationship between the work functions of the first electrode, the second electrode, and the nanoparticles. 図４は、電極の仕事関数とアニール温度との関係を示す図である。FIG. 4 is a diagram showing the relationship between the work function of the electrode and the annealing temperature. 図５は、第１電極、第２電極及びナノ粒子の仕事関数の関係を示す図である。FIG. 5 is a diagram showing the relationship between the work functions of the first electrode, the second electrode, and the nanoparticles. 図６は、この発明の第２実施形態に係る発電素子の一例を示す模式断面図である。FIG. 6 is a schematic cross-sectional view showing an example of the power generation element according to the second embodiment of the present invention. 図７は、第１電極、第２電極及びナノ粒子の仕事関数の関係を示す図である。FIG. 7 is a diagram showing the relationship between the work functions of the first electrode, the second electrode, and the nanoparticles. 図８は、この発明の第３実施形態に係る発電素子の一例を示す模式断面図である。FIG. 8 is a schematic cross-sectional view showing an example of the power generation element according to the third embodiment of the present invention. 図９は、第１電極、第２電極及びナノ粒子の仕事関数の関係を示す図である。FIG. 9 is a diagram showing the relationship between the work functions of the first electrode, the second electrode, and the nanoparticles. 図１０は、この発明の第４実施形態に係る発電素子の一例を示す模式断面図である。FIG. 10 is a schematic cross-sectional view showing an example of a power generation element according to a fourth embodiment of the present invention. 図１１は、この発明の第５実施形態に係る発電素子の一例を示す模式断面図である。FIG. 11 is a schematic cross-sectional view showing an example of the power generation element according to the fifth embodiment of the present invention. 図１２は、この発明の第６実施形態に係る発電素子の一例を示す模式断面図である。FIG. 12 is a schematic cross-sectional view showing an example of the power generation element according to the sixth embodiment of the present invention. 図１３は、この発明の第７実施形態に係る発電素子の一例を示す模式断面図である。FIG. 13 is a schematic cross-sectional view showing an example of the power generation element according to the seventh embodiment of the present invention. 図１４は、この発明の第８実施形態に係る発電素子の製造方法の一例を示す流れ図である。FIG. 14 is a flow chart showing an example of a method for manufacturing a power generation element according to an eighth embodiment of the present invention. 図１５（ａ）～図１５（ｄ）は、発電素子を備えた電子機器の例を示す模式ブロック図である。図１５（ｅ）～図１５（ｈ）は、発電素子を含む発電装置を備えた電子機器の例を示す模式ブロック図である。15 (a) to 15 (d) are schematic block diagrams showing an example of an electronic device provided with a power generation element. 15 (e) to 15 (h) are schematic block diagrams showing an example of an electronic device including a power generation device including a power generation element.
　以下、この発明の実施形態のいくつかを、図面を参照しながら説明する。各図において、共通する部分については共通する参照符号を付し、重複する説明は省略する。 Hereinafter, some embodiments of the present invention will be described with reference to the drawings. In each figure, common reference numerals are given to common parts, and duplicate description is omitted.
第１実施形態
（発電素子）
　図１（ａ）は、この発明の第１実施形態に係る発電素子の一例を示す模式断面図である。図１（ｂ）は、この発明の第１実施形態に係る発電素子を用いた発電装置の一例を示す模式断面図である。 1st Embodiment (power generation element)
FIG. 1A is a schematic cross-sectional view showing an example of a power generation element according to the first embodiment of the present invention. FIG. 1B is a schematic cross-sectional view showing an example of a power generation device using a power generation element according to the first embodiment of the present invention.
　第１実施形態に係る発電素子１は、第１電極１１と、第２電極１２と、中間部１３と、を含む。 The power generation element 1 according to the first embodiment includes a first electrode 11, a second electrode 12, and an intermediate portion 13.
　第１電極１１は、第１基板２１上に設けられている。第１電極１１は、この実施形態ではカソードＫである。第１基板２１は、絶縁性又は導電性の基板である。この実施形態では、絶縁性の基板が第１基板２１に用いられている。絶縁性の基板の一例は、ガラス基板である。第２電極１２は、第２基板２２上に設けられている。第２電極１２は、この実施形態ではアノードＡである。第２電極１２の仕事関数の値φＡは、第１電極１１の仕事関数の値φＫと異なる。第１電極１１がカソードＫであり、第２電極１２がアノードＡである場合、仕事関数の値φＫは、仕事関数の値φＡよりも小さい（φＫ＜φＡ）。第２電極１２は、第１電極１１とギャップＧを介して対向する。第２基板２２は、絶縁性又は導電性の基板である。この実施形態では、第１基板２１及び第２基板２２のそれぞれは、同じ絶縁性物質から構成された基板又は同じ導電性物質から構成された基板である。この実施形態では、第１基板２１と同じガラス基板が第２基板２２に用いられている。基板は、強固な基板に限らず、フレキシブルな基板を用いることもできる。 The first electrode 11 is provided on the first substrate 21. The first electrode 11 is the cathode K in this embodiment. The first substrate 21 is an insulating or conductive substrate. In this embodiment, an insulating substrate is used for the first substrate 21. An example of an insulating substrate is a glass substrate. The second electrode 12 is provided on the second substrate 22. The second electrode 12 is the anode A in this embodiment. The work function value φA of the second electrode 12 is different from the work function value φK of the first electrode 11. When the first electrode 11 is the cathode K and the second electrode 12 is the anode A, the work function value φK is smaller than the work function value φA (φK <φA). The second electrode 12 faces the first electrode 11 via the gap G. The second substrate 22 is an insulating or conductive substrate. In this embodiment, each of the first substrate 21 and the second substrate 22 is a substrate made of the same insulating substance or a substrate made of the same conductive substance. In this embodiment, the same glass substrate as the first substrate 21 is used for the second substrate 22. The substrate is not limited to a strong substrate, and a flexible substrate can also be used.
　この実施形態では、発電素子１は、第１基板２１と第２基板２２との間に、支持部２３を有する。発電素子１が支持部２３を有する場合、支持部２３のＺ方向の高さＨ２３が、第１電極１１と第２電極１２との間の電極間ギャップＧＥを、ほぼ決定する。図１（ａ）中に示すＸ、Ｙ、Ｚは、三次元直交座標系を示している。電極間ギャップＧＥの一例は、１μｍ以下の有限値である。電極間ギャップＧＥを狭くすると、電気エネルギーの出力が向上する。 In this embodiment, the power generation element 1 has a support portion 23 between the first substrate 21 and the second substrate 22. When the power generation element 1 has the support portion 23, the height H23 of the support portion 23 in the Z direction substantially determines the inter-electrode gap GE between the first electrode 11 and the second electrode 12. X, Y, and Z shown in FIG. 1A indicate a three-dimensional Cartesian coordinate system. An example of the gap between electrodes GE is a finite value of 1 μm or less. When the gap GE between electrodes is narrowed, the output of electrical energy is improved.
　図２（ａ）は中間部１３の一例を示す模式断面図である。 FIG. 2A is a schematic cross-sectional view showing an example of the intermediate portion 13.
　図２（ａ）に示すように、中間部１３は、ギャップＧ内に設けられている。中間部１３は、図２（ａ）に示すように、第１電極１１（カソードＫ）から放出された電子ｅを、第２電極１２（アノードＡ）へと移動させる部分である。なお、図２（ａ）には、第２電極１２のうち、後述する酸化物１２ａの部分が示されている。中間部１３は、ナノ粒子１４を含む。ナノ粒子１４の仕事関数の値φＮは、第１電極１１の仕事関数の値φＫと第２電極１２の仕事関数の値φＡとの間にある（φＫ＜φＮ＜φＡ）。このような仕事関数の値φＮを有する物質が、ナノ粒子１４として選ばれる。 As shown in FIG. 2A, the intermediate portion 13 is provided in the gap G. As shown in FIG. 2A, the intermediate portion 13 is a portion that moves the electrons e emitted from the first electrode 11 (cathode K) to the second electrode 12 (anode A). Note that FIG. 2A shows a portion of the second electrode 12 where the oxide 12a will be described later. The intermediate portion 13 contains nanoparticles 14. The work function value φN of the nanoparticles 14 is between the work function value φK of the first electrode 11 and the work function value φA of the second electrode 12 (φK <φN <φA). A substance having such a work function value φN is selected as the nanoparticles 14.
　ナノ粒子１４の粒子径は、例えば２ｎｍ以上１０ｎｍ以下である。ナノ粒子１４は、例えば、平均粒径（例えばＤ５０）３ｎｍ以上８ｎｍ以下の粒子径を有してもよい。平均粒径は、例えば粒度分布計測器を用いることで、測定することができる。粒度分布計測器としては、例えば、レーザー回折散乱法を用いた粒度分布計測器（例えばMicrotracBEL製Nanotrac WaveII-EX150等）を用いればよい。 The particle size of the nanoparticles 14 is, for example, 2 nm or more and 10 nm or less. The nanoparticles 14 may have, for example, an average particle size (for example, D50) of 3 nm or more and 8 nm or less. The average particle size can be measured by using, for example, a particle size distribution measuring instrument. As the particle size distribution measuring instrument, for example, a particle size distribution measuring instrument using a laser diffraction / scattering method (for example, Nanotrac Wave II-EX150 manufactured by Microtrac BEL) may be used.
　ナノ粒子１４は、その表面に、例えば絶縁膜１４ａを有する。絶縁膜１４ａの材料の例としては、絶縁性金属化合物及び絶縁性有機化合物の少なくとも１つを選ぶことができる。絶縁性金属化合物の例としては、例えば、シリコン酸化物及びアルミナ等を挙げることができる。絶縁性有機化合物の例としては、アルカンチオール（例えばドデカンチオール）等を挙げることができる。絶縁膜１４ａの厚さは、例えば２０ｎｍ以下の有限値である。このような絶縁膜１４ａをナノ粒子１４の表面に設けておくと、電子ｅは、例えば、第１電極１１（カソードＫ）とナノ粒子１４との間、並びにナノ粒子１４と第２電極１２（アノードＡ）との間を、トンネル効果を利用して移動できる。このため、例えば、発電素子１の発電効率の向上が期待できる。 The nanoparticles 14 have, for example, an insulating film 14a on the surface thereof. As an example of the material of the insulating film 14a, at least one of an insulating metal compound and an insulating organic compound can be selected. Examples of the insulating metal compound include, for example, silicon oxide and alumina. Examples of the insulating organic compound include alkanethiol (for example, dodecanethiol) and the like. The thickness of the insulating film 14a is, for example, a finite value of 20 nm or less. When such an insulating film 14a is provided on the surface of the nanoparticles 14, the electrons e are, for example, between the first electrode 11 (cathode K) and the nanoparticles 14, and the nanoparticles 14 and the second electrode 12 ( It can move to and from the anode A) using the tunnel effect. Therefore, for example, improvement in power generation efficiency of the power generation element 1 can be expected.
　ギャップＧ内は、溶媒１５によって満たされている。例えば、ナノ粒子１４は、溶媒１５中に分散されている。溶媒１５には、例えば、沸点が６０℃以上の液体を用いることができる。このような液体を用いることで、室温（例えば１５℃～３５℃）以上の環境下において、発電素子１を用いた場合であっても、溶媒１５の気化を抑制することができる。これにより、溶媒１５の気化に伴う発電素子１の劣化を抑制することができる。液体の例としては、有機溶媒及び水の少なくとも１つを選ぶことができる。有機溶媒の例としては、メタノール、エタノール、トルエン、キシレン、テトラデカン、アルカンチオール等を挙げることができる。溶媒１５は、電気的抵抗値が高く、絶縁性である液体がよい。また、ナノ粒子１４を、溶媒１５に分散させておくと、図２（ａ）の矢印に示すように、ナノ粒子１４の移動を利用することで、電子ｅの移動を、さらに促すこともできる。 The inside of the gap G is filled with the solvent 15. For example, the nanoparticles 14 are dispersed in the solvent 15. As the solvent 15, for example, a liquid having a boiling point of 60 ° C. or higher can be used. By using such a liquid, it is possible to suppress the vaporization of the solvent 15 even when the power generation element 1 is used in an environment of room temperature (for example, 15 ° C. to 35 ° C.) or higher. As a result, deterioration of the power generation element 1 due to vaporization of the solvent 15 can be suppressed. As an example of a liquid, at least one of an organic solvent and water can be selected. Examples of the organic solvent include methanol, ethanol, toluene, xylene, tetradecane, alkanethiol and the like. The solvent 15 is preferably a liquid having a high electrical resistance value and being insulating. Further, when the nanoparticles 14 are dispersed in the solvent 15, as shown by the arrow in FIG. 2A, the movement of the electrons e can be further promoted by utilizing the movement of the nanoparticles 14. ..
　図２（ｂ）は中間部１３の他の例を示す模式断面図である。 FIG. 2B is a schematic cross-sectional view showing another example of the intermediate portion 13.
　図２（ｂ）に示すように、ナノ粒子１４は、溶媒１５を使用することなく、ギャップＧ内に充填されてもよい。なお、図２（ｂ）には、第２電極１２のうち、後述する酸化物１２ａの部分が示されている。 As shown in FIG. 2B, the nanoparticles 14 may be filled in the gap G without using the solvent 15. Note that FIG. 2B shows the portion of the oxide 12a described later in the second electrode 12.
　発電素子１によれば、第１電極１１と第２電極１２との間に発生する、絶対温度による電子放出現象を利用できる。このため、発電素子１は、第１電極１１と第２電極１２との温度差が小さい場合であっても、熱エネルギーを電気エネルギーに変換できる。さらに、発電素子１は、第１電極１１と第２電極１２との間に温度差がない場合又は単一の熱源を用いる場合であっても、熱エネルギーを電気エネルギーに変換することができる。 According to the power generation element 1, the electron emission phenomenon due to the absolute temperature generated between the first electrode 11 and the second electrode 12 can be used. Therefore, the power generation element 1 can convert thermal energy into electrical energy even when the temperature difference between the first electrode 11 and the second electrode 12 is small. Further, the power generation element 1 can convert thermal energy into electrical energy even when there is no temperature difference between the first electrode 11 and the second electrode 12 or when a single heat source is used.
　発電素子１では、第１電極１１及び第２電極１２のそれぞれは、同じ導電性物質である。しかしながら、第２電極１２のギャップＧに面した表面の状態は、第１電極１１のギャップＧに面した表面の状態と異なる。ギャップＧに面した表面の状態が異なることによって、第１電極１１及び第２電極１２のそれぞれが同じ導電性物質でありながらも、第１電極１１の仕事関数の値φＫ、第２電極１２の仕事関数の値φＡ及びナノ粒子１４の仕事関数の値φＮの関係を、
　　φＫ　＜　φＮ　＜　φＡ
とすることができる。 In the power generation element 1, each of the first electrode 11 and the second electrode 12 is the same conductive substance. However, the state of the surface of the second electrode 12 facing the gap G is different from the state of the surface of the first electrode 11 facing the gap G. Due to the difference in the state of the surface facing the gap G, although the first electrode 11 and the second electrode 12 are the same conductive material, the work function value φK of the first electrode 11 and the second electrode 12 The relationship between the work function value φA and the work function value φN of the nanoparticles 14
φK <φN <φA
Can be.
　ギャップＧに面した表面の状態が異なる例の１つは、例えば、第１電極１１のギャップＧに面した表面には酸化物が無く、第２電極１２のギャップＧに面した表面には、導電性物質の酸化物１２ａが有ることである。酸化物１２ａは、例えば導電性物質の酸化被膜である。ギャップＧに面した表面の状態が異なる別の例は、後述する。 One example in which the state of the surface facing the gap G is different is that, for example, the surface of the first electrode 11 facing the gap G has no oxide, and the surface of the second electrode 12 facing the gap G has no oxide. There is an oxide 12a of the conductive substance. The oxide 12a is, for example, an oxide film of a conductive substance. Another example in which the state of the surface facing the gap G is different will be described later.
　なお、この実施形態では、第２電極１２のギャップＧに面した表面の状態の全てが、第１電極１１のギャップＧに面した表面の状態と異なっている場合を示した。しかし、第２電極１２のギャップＧに面した表面の状態の全てが、第１電極１１のギャップＧに面した表面の状態と異なっている必要はない。例えば、第２電極１２の少なくとも第１電極１１と対向する面の状態が、第１電極１１の少なくとも第２電極１２と対向する面の状態と異なっていれば良い。この事項は、後述する全ての実施形態で共通する。 In this embodiment, the case where all the states of the surface of the second electrode 12 facing the gap G are different from the state of the surface of the first electrode 11 facing the gap G is shown. However, it is not necessary that all the state of the surface of the second electrode 12 facing the gap G is different from the state of the surface of the first electrode 11 facing the gap G. For example, the state of the surface of the second electrode 12 facing at least the first electrode 11 may be different from the state of the surface of the first electrode 11 facing at least the second electrode 12. This matter is common to all the embodiments described later.
　＜発電素子の動作＞
　熱エネルギーが発電素子１に与えられると、第１電極１１（カソードＫ）から中間部１３に向けて電子ｅが放出される。放出された電子ｅは、中間部１３から第２電極１２（アノードＡ）へと移動する（図２（ａ）又は図２（ｂ）参照）。電流は、第２電極１２から第１電極１１に向かって流れる。このようにして、熱エネルギーが電気エネルギーに変換される。 <Operation of power generation element>
When thermal energy is applied to the power generation element 1, electrons e are emitted from the first electrode 11 (cathode K) toward the intermediate portion 13. The emitted electrons e move from the intermediate portion 13 to the second electrode 12 (anode A) (see FIG. 2 (a) or FIG. 2 (b)). The current flows from the second electrode 12 toward the first electrode 11. In this way, thermal energy is converted into electrical energy.
　放出される電子ｅの量は、熱エネルギーに依存するほか、第１電極１１の仕事関数と、第２電極１２の仕事関数との差に依存する。また、放出される電子ｅの量は、第１電極１１の仕事関数が小さい材料ほど、増加する傾向がある。 The amount of emitted electrons e depends not only on the thermal energy but also on the difference between the work function of the first electrode 11 and the work function of the second electrode 12. Further, the amount of emitted electrons e tends to increase as the work function of the first electrode 11 becomes smaller.
　移動する電子ｅの量は、例えば、第１電極１１と第２電極１２との仕事関数の差を大きくすること、又は電極間ギャップＧＥを小さくすることで増やすことができる。例えば、発電素子１が発生させる電気エネルギーの量は、仕事関数の差を大きくすること及び電極間ギャップＧＥを小さくすること、の少なくともいずれか１つを考慮することで増加させることができる。 The amount of moving electrons e can be increased, for example, by increasing the difference in work function between the first electrode 11 and the second electrode 12, or by reducing the gap GE between the electrodes. For example, the amount of electrical energy generated by the power generation element 1 can be increased by considering at least one of increasing the difference in work functions and reducing the gap GE between electrodes.
　＜発電装置＞
　図１（ｂ）に示すように、発電装置１００は、発電素子１と、第１外部端子１０１と、第２外部端子１０２と、を含む。この実施形態では、第１外部端子１０１は、第１電極１１と電気的に接続される。第１外部端子１０１は、カソードＫである。第２外部端子１０２は、第２電極１２と電気的に接続される。第２外部端子１０２は、アノードＡである。発電素子１を含む発電装置１００は、例えば、図示せぬ熱源に搭載又は設置され、熱源の熱エネルギーを元として、発電素子１が発生させた電気エネルギーを、第１外部端子１０１及び第２外部端子１０２を介して負荷Ｒへ出力する。負荷Ｒの一端は、第１外部配線１１１を介して第１外部端子１０１と電気的に接続される。負荷Ｒの他端は、第２外部配線１１２を介して第２外部端子１０２と電気的に接続される。負荷Ｒは、例えば電気的な機器を示している。負荷Ｒは、発電装置１００を主電源又は補助電源に用いて駆動される。 <Power generation device>
As shown in FIG. 1B, the power generation device 100 includes a power generation element 1, a first external terminal 101, and a second external terminal 102. In this embodiment, the first external terminal 101 is electrically connected to the first electrode 11. The first external terminal 101 is a cathode K. The second external terminal 102 is electrically connected to the second electrode 12. The second external terminal 102 is the anode A. The power generation device 100 including the power generation element 1 is mounted or installed on a heat source (not shown), and the electric energy generated by the power generation element 1 based on the heat energy of the heat source is used as the first external terminal 101 and the second outside. Output to the load R via the terminal 102. One end of the load R is electrically connected to the first external terminal 101 via the first external wiring 111. The other end of the load R is electrically connected to the second external terminal 102 via the second external wiring 112. The load R indicates, for example, an electrical device. The load R is driven by using the power generation device 100 as a main power source or an auxiliary power source.
　発電素子１の熱源としては、例えば、ＣＰＵ（Central Processing Unit）等の電子デバイス又は電子部品、ＬＥＤ（Light Emitting Diode）等の発光素子、自動車等のエンジン、工場の生産設備、人体、太陽光、環境温度等を利用することができる。例えば、電子デバイス、電子部品、発光素子、エンジン、生産設備等は人工熱源である。人体、太陽光、環境温度等は自然熱源である。発電装置１００は、例えばＩｏＴ（Internet of Things）デバイス及びウェアラブル機器等のモバイル機器や自立型センサ端末の内部に設けることができ、電池の代替又は補助として用いることができる。さらに、発電装置１００は、太陽光発電等のような、より大型の発電装置への応用も可能である。 Examples of the heat source of the power generation element 1 include electronic devices or electronic components such as a CPU (Central Processing Unit), light emitting elements such as LEDs (Light Emitting Diodes), engines such as automobiles, factory production equipment, human bodies, sunlight, and the like. Environmental temperature etc. can be used. For example, electronic devices, electronic components, light emitting elements, engines, production equipment, and the like are artificial heat sources. The human body, sunlight, environmental temperature, etc. are natural heat sources. The power generation device 100 can be provided inside a mobile device such as an IoT (Internet of Things) device and a wearable device, or a self-supporting sensor terminal, and can be used as a substitute or an auxiliary for a battery. Further, the power generation device 100 can also be applied to a larger power generation device such as solar power generation.
（電極の仕事関数の制御方法）
　図３は、第１電極１１、第２電極１２及びナノ粒子１４の仕事関数の関係を示す図である。 (Control method of electrode work function)
FIG. 3 is a diagram showing the relationship between the work functions of the first electrode 11, the second electrode 12, and the nanoparticles 14.
　図３に示すように、第１電極１１と第２電極１２とを同じ物質で形成した場合、第１電極１１の仕事関数は、第２電極１２の仕事関数と等しくなる。この状態では、第１電極１１の仕事関数の値φＫと第２電極１２の仕事関数の値φＡとの間に差がない。このため、発電素子として機能させることは難しい。図３では、第１電極１１及び第２電極１２それぞれの仕事関数が、ナノ粒子の仕事関数よりも小さい場合が示されている。このような関係は、例えば、第１電極１１及び第２電極１２のそれぞれをＴｉ（チタン）とし、ナノ粒子１４をＡｕ（金）とした例に見ることができる。 As shown in FIG. 3, when the first electrode 11 and the second electrode 12 are formed of the same substance, the work function of the first electrode 11 is equal to the work function of the second electrode 12. In this state, there is no difference between the work function value φK of the first electrode 11 and the work function value φA of the second electrode 12. Therefore, it is difficult to make it function as a power generation element. FIG. 3 shows a case where the work function of each of the first electrode 11 and the second electrode 12 is smaller than the work function of the nanoparticles. Such a relationship can be seen in, for example, an example in which each of the first electrode 11 and the second electrode 12 is Ti (titanium) and the nanoparticles 14 are Au (gold).
　本件の発明者らは、第１電極１１と第２電極１２とが同じ導電性物質からなる場合でも、第１電極１１の仕事関数と第２電極１２の仕事関数とを異ならせることができるか否かについて考察した。実現可能であれば、第１電極１１及び第２電極１２のそれぞれが異なる導電性物質で形成される現状を打破できる。例えば、第１電極１１の導電性物質としてＴｉを選び、第２電極１２の導電性物質としてＰｔ（白金）を選ぶなどである。このような現状を打破できれば、少なくとも
　・異なった導電性物質ごとに、原料を購入する必要があること
　・異なった導電性物質ごとに、高価な成膜装置又は高価な製造ラインを用意する必要があること
という事情を解消でき、発電素子の製造コストを抑制することが可能になる。 Can the inventors of the present case make the work function of the first electrode 11 different from the work function of the second electrode 12 even when the first electrode 11 and the second electrode 12 are made of the same conductive substance? I considered whether or not. If feasible, it is possible to break through the current situation in which the first electrode 11 and the second electrode 12 are each made of different conductive substances. For example, Ti is selected as the conductive substance of the first electrode 11, and Pt (platinum) is selected as the conductive substance of the second electrode 12. If this situation can be overcome, at least: -It is necessary to purchase raw materials for each different conductive substance-It is necessary to prepare an expensive film forming equipment or an expensive production line for each different conductive substance. It is possible to eliminate the situation that there is, and to suppress the manufacturing cost of the power generation element.
　＜アニール特性＞
　図４は、電極の仕事関数とアニール温度との関係を示す図である。 <Annealing characteristics>
FIG. 4 is a diagram showing the relationship between the work function of the electrode and the annealing temperature.
　現状を打破するために、第１電極１１及び第２電極１２を模した複数の試験片が用意された。試験片は、ガラス基板上に、第１電極１１及び第２電極１２として、Ｔｉ膜を形成したものである。試験片は、６つが用意された（第１試験片ＴＰ１～第６試験片ＴＰ６）。第２試験片ＴＰ２～第６試験片ＴＰ６のそれぞれには、１００℃、１５０℃、２００℃、２５０℃、３００℃の熱アニールが実施された。第１試験片ＴＰ１は、室温（この実施形態では２５℃）のままとされた。 In order to break through the current situation, a plurality of test pieces imitating the first electrode 11 and the second electrode 12 were prepared. The test piece has a Ti film formed on a glass substrate as the first electrode 11 and the second electrode 12. Six test pieces were prepared (first test piece TP1 to sixth test piece TP6). The second test piece TP2 to the sixth test piece TP6 were subjected to thermal annealing at 100 ° C., 150 ° C., 200 ° C., 250 ° C., and 300 ° C., respectively. The first test piece TP1 was left at room temperature (25 ° C. in this embodiment).
　熱アニールの条件の一例を、以下に示す。
　　雰囲気　　　：大気
　　アニール時間：１分
　　圧力　　　　：大気圧（約１０１３００Ｐａ）
　　加熱後の冷却：無し（室温に戻すのみ） An example of thermal annealing conditions is shown below.
Atmosphere: Atmosphere Annealing time: 1 minute Pressure: Atmospheric pressure (approx. 101300 Pa)
Cooling after heating: None (return to room temperature only)
　図４には、ナノ粒子１４の仕事関数を基準（０）とし、Ｔｉ膜の仕事関数と、ナノ粒子１４の仕事関数との差が示されている。ナノ粒子１４には、Ａｕを仮定した。Ａｕの仕事関数は、例えば５．４ｅＶとした。 FIG. 4 shows the difference between the work function of the Ti film and the work function of the nanoparticles 14 with the work function of the nanoparticles 14 as the reference (0). Au was assumed for the nanoparticles 14. The work function of Au was set to, for example, 5.4 eV.
　図４に示すように、試験後のＴｉ膜の仕事関数と、ナノ粒子１４の仕事関数との差は、以下の通りである。
　　第１試験片ＴＰ１：約－０．５８ｅＶ　（アニール無し：２５℃）
　　第２試験片ＴＰ２：約－０．５ｅＶ　　（アニール有り：１００℃）
　　第３試験片ＴＰ３：約－０．３ｅＶ　　（アニール有り：１５０℃）
　　第４試験片ＴＰ４：約＋０．０７ｅＶ　（アニール有り：２００℃）
　　第５試験片ＴＰ５：約＋０．１３ｅＶ　（アニール有り：２５０℃）
　　第６試験片ＴＰ６：約＋０．２５ｅＶ　（アニール有り：３００℃） As shown in FIG. 4, the difference between the work function of the Ti film after the test and the work function of the nanoparticles 14 is as follows.
First test piece TP1: Approximately -0.58 eV (without annealing: 25 ° C)
Second test piece TP2: Approximately -0.5 eV (with annealing: 100 ° C)
Third test piece TP3: Approximately -0.3 eV (with annealing: 150 ° C)
Fourth test piece TP4: Approximately +0.07 eV (with annealing: 200 ° C)
Fifth test piece TP5: Approximately +0.13 eV (with annealing: 250 ° C)
6th test piece TP6: Approximately +0.25 eV (with annealing: 300 ° C)
　この試験結果から、第１電極１１と第２電極１２とが同じ導電性物質からなる場合でも、第１電極１１の仕事関数と第２電極１２の仕事関数とを異ならせることができること、が確認された。 From this test result, it was confirmed that the work function of the first electrode 11 and the work function of the second electrode 12 can be different even when the first electrode 11 and the second electrode 12 are made of the same conductive substance. Was done.
　第１試験片ＴＰ１～第３試験片ＴＰ３の仕事関数の値は、ナノ粒子１４の仕事関数よりも低い。しかし、第４試験片ＴＰ４～第６試験片ＴＰ６の仕事関数の値は、ナノ粒子１４の仕事関数よりも高い。即ち、アニールすることによって、仕事関数の値は、ナノ粒子１４の仕事関数の値を超えて変化する。この知見から、例えば、第２電極１２をアニールすることによって、第２電極１２の仕事関数の値を、第１電極１１の仕事関数の値から、ナノ粒子１４の仕事関数の値を超えて変化させることが可能であることが確認された。 The value of the work function of the first test piece TP1 to the third test piece TP3 is lower than the work function of the nanoparticles 14. However, the value of the work function of the fourth test piece TP4 to the sixth test piece TP6 is higher than the work function of the nanoparticles 14. That is, by annealing, the value of the work function changes beyond the value of the work function of the nanoparticles 14. From this finding, for example, by annealing the second electrode 12, the value of the work function of the second electrode 12 is changed from the value of the work function of the first electrode 11 beyond the value of the work function of the nanoparticles 14. It was confirmed that it was possible to make it.
　また、Ｔｉのアニール特性から、導電性物質として第４族元素を用いた場合には、アニール温度は、３００℃以上第４族元素の融点以下であることが良い。 Further, from the annealing characteristics of Ti, when a Group 4 element is used as the conductive substance, the annealing temperature is preferably 300 ° C. or higher and lower than the melting point of the Group 4 element.
　図５は、第１電極１１、第２電極１２及びナノ粒子１４の仕事関数の関係を示す図である。 FIG. 5 is a diagram showing the relationship between the work functions of the first electrode 11, the second electrode 12, and the nanoparticles 14.
　図５に示すように、第２電極１２をアニールすれば、第２電極１２の仕事関数の値を、ナノ粒子１４の仕事関数の値よりも大きくできる。例えば、第１電極１１及び第２電極１２のそれぞれをＴｉとし、ナノ粒子１４をＡｕとした例では、第１電極１１及び第２電極１２のそれぞれが同じ導電性物質でありながらも、第１電極１１の仕事関数の値φＫ、第２電極１２の仕事関数の値φＡ及びナノ粒子１４の仕事関数の値φＮの関係を、
　　φＫ　＜　φＮ　＜　φＡ
とすることができる。つまり、発電素子１では、第１電極１１及び第２電極１２のそれぞれが同じ導電性物質でありながらも、第１電極１１をカソードＫとし、第２電極１２をアノードＡとして使用可能であることが確認された。 As shown in FIG. 5, if the second electrode 12 is annealed, the work function value of the second electrode 12 can be made larger than the work function value of the nanoparticles 14. For example, in an example in which each of the first electrode 11 and the second electrode 12 is Ti and the nanoparticles 14 are Au, the first electrode 11 and the second electrode 12 are the same conductive material, but the first electrode is the first. The relationship between the work function value φK of the electrode 11, the work function value φA of the second electrode 12, and the work function value φN of the nanoparticles 14.
φK <φN <φA
Can be. That is, in the power generation element 1, although the first electrode 11 and the second electrode 12 are each the same conductive material, the first electrode 11 can be used as the cathode K and the second electrode 12 can be used as the anode A. Was confirmed.
　発電素子１のような発電素子においては、カソードＫにＡｌ（アルミニウム）を用い、アノードＡにＰｔを用い、そして、ナノ粒子１４にＡｕを用いることが検討されている。Ａｌの仕事関数とＡｕの仕事関数の差は、約－０．８８ｅＶである。Ｐｔの仕事関数とＡｕの仕事関数の差は、約＋０．２２ｅＶである。仕事関数の差の絶対値は、約１．１ｅＶである。 In a power generation element such as the power generation element 1, it has been studied to use Al (aluminum) for the cathode K, Pt for the anode A, and Au for the nanoparticles 14. The difference between the work function of Al and the work function of Au is about −0.88 eV. The difference between the work function of Pt and the work function of Au is about +0.22 eV. The absolute value of the work function difference is about 1.1 eV.
　この実施形態においては、第１試験片ＴＰ１の仕事関数とＡｕの仕事関数との差は、約－０．５８ｅＶである。第６試験片ＴＰ６の仕事関数とＡｕの仕事関数との差は、約＋０．２５ｅＶである。仕事関数の差の絶対値は、約０．８３ｅＶである。この絶対値は、検討されている発電素子における仕事関数の差の絶対値とは異なる。しかし、仕事関数の差の絶対値が、約０．８３ｅＶであれば、発電素子として機能することができる。 In this embodiment, the difference between the work function of the first test piece TP1 and the work function of Au is about -0.58 eV. The difference between the work function of the sixth test piece TP6 and the work function of Au is about +0.25 eV. The absolute value of the work function difference is about 0.83 eV. This absolute value is different from the absolute value of the difference in work functions in the power generation element under consideration. However, if the absolute value of the difference between the work functions is about 0.83 eV, it can function as a power generation element.
　ここで、第１電極１１及び第２電極１２のそれぞれが同じ導電性物質でありながらも、仕事関数が異なることが可能な理由の１つを述べる。 Here, one of the reasons why the work functions can be different even though the first electrode 11 and the second electrode 12 are the same conductive substance will be described.
　この実施形態では、熱アニールの条件において、雰囲気を大気とした。大気は、Ｏ2（酸素分子）を含む。大気は、酸化性雰囲気の１つである。つまり、第２電極１２を模したＴｉ膜がアニールされることによって、このＴｉ膜が酸化された又はＴｉ膜の酸化が更に進んだことが考えられる。第２電極１２をアニールすれば、少なくとも第２電極１２の表面の状態を、第１電極１１の表面の状態と異ならせることができる。第２電極１２の表面の状態が、第１電極１１の表面の状態と異なれば、第１電極１１及び第２電極１２のそれぞれが同じ導電性物質でありながらも、第１電極１１（カソードＫ）の仕事関数の値φＫ、第２電極１２（アノードＡ）の仕事関数の値φＡ及びナノ粒子１４の仕事関数の値φＮの関係を、
　　φＫ　＜　φＮ　＜　φＡ
とすることができる。 In this embodiment, the atmosphere was the atmosphere under the conditions of thermal annealing. The atmosphere contains O 2 (oxygen molecules). The atmosphere is one of the oxidizing atmospheres. That is, it is considered that the Ti film imitating the second electrode 12 is annealed, so that the Ti film is oxidized or the Ti film is further oxidized. By annealing the second electrode 12, at least the state of the surface of the second electrode 12 can be made different from the state of the surface of the first electrode 11. If the surface condition of the second electrode 12 is different from the surface condition of the first electrode 11, the first electrode 11 (cathode K) is different from the surface condition of the first electrode 11 even though the first electrode 11 and the second electrode 12 are the same conductive material. ), The work function value φK, the work function value φA of the second electrode 12 (anode A), and the work function value φN of the nanoparticles 14.
φK <φN <φA
Can be.
　したがって、第１実施形態によれば、発電素子の製造コストを抑制することが可能な電極の仕事関数の制御方法及び発電素子及び発電素子の製造方法を提供できる。 Therefore, according to the first embodiment, it is possible to provide a method of controlling the work function of the electrode and a method of manufacturing the power generation element and the power generation element, which can suppress the manufacturing cost of the power generation element.
　なお、導電性物質は、Ｔｉに限られるものではない。アニールによって、少なくとも表面の状態を異ならせることが可能な導電性物質であれば良い。導電性物質は、第４族元素から選ばれることが良い。なぜならば、第４族元素は融点が高く、熱膨張率及びヤング率も比較的小さい。このため、アニールに耐えやすい導電性物質である。また、第４族元素は入手しやすい。第４族元素の中でも、例えばＴｉは入手しやすく、かつ、安価である。第４族元素は、この発明の実施形態の実施に有用な導電性物質の１つである。この事項は、後述する全ての実施形態で共通する。 The conductive substance is not limited to Ti. Any conductive substance that can at least change the surface condition by annealing may be used. The conductive substance is preferably selected from Group 4 elements. This is because Group 4 elements have a high melting point and a relatively small coefficient of thermal expansion and Young's modulus. Therefore, it is a conductive substance that can easily withstand annealing. In addition, Group 4 elements are easily available. Among the Group 4 elements, for example, Ti is easily available and inexpensive. Group 4 elements are one of the conductive substances useful in carrying out the embodiments of the present invention. This matter is common to all the embodiments described later.
　また、アニールの方法は、熱アニールに限られるものではない。少なくとも電極の表面の状態が異ならせることが可能なアニールの方法であれば、用いることができる。そのようなアニールとしては、熱アニールのほか、レーザアニール、光アニール等を挙げることができる。アニールの方法は、熱アニール、レーザアニール及び光アニールの１つを選ぶことが可能である。さらに、これらのアニール方法を、様々に組み合わせることも可能である。即ち、第１実施形態では、アニールは、熱アニール、レーザアニール及び光アニールの少なくとも１つを含めば良い。この事項は、後述する全ての実施形態で共通する。 Also, the annealing method is not limited to thermal annealing. At least, any annealing method that can make the surface condition of the electrode different can be used. Examples of such annealing include thermal annealing, laser annealing, optical annealing, and the like. As the annealing method, one of thermal annealing, laser annealing and optical annealing can be selected. Furthermore, these annealing methods can be combined in various ways. That is, in the first embodiment, the annealing may include at least one of thermal annealing, laser annealing, and optical annealing. This matter is common to all the embodiments described later.
　また、この明細書では、アニールは「圧力の印加」を含むものとする。導電性物質の中には、高い圧力を印加することによって、少なくとも電極の表面の状態が変化するものがあるためである。この事項は、後述する全ての実施形態で共通する。 Also, in this specification, annealing shall include "applying pressure". This is because some conductive substances change at least the state of the surface of the electrode by applying a high pressure. This matter is common to all the embodiments described later.
　また、アニールの条件は、雰囲気を大気とした。大気は酸化性雰囲気の１つである。雰囲気が大気であれば酸化剤が不要である。このため、アニールを安価に行うことができる。しかし、酸化性雰囲気は、大気に限られることはない。酸化性雰囲気は、例えば、
　　・大気よりも多くの酸素分子（Ｏ2）を含む雰囲気
　　・大気よりも多くの水蒸気を含む雰囲気
　　・酸素同素体（Ｏ3（オゾン）、酸素クラスター等）を含む雰囲気
　　・酸素化合物を含む雰囲気
　　・ヒドロキシ基（－ＯＨ）を有する化合物を含む雰囲気
であっても良い。この事項は、後述する全ての実施形態で共通する。 The annealing condition was that the atmosphere was the atmosphere. The atmosphere is one of the oxidizing atmospheres. If the atmosphere is atmospheric, no oxidizer is required. Therefore, annealing can be performed at low cost. However, the oxidizing atmosphere is not limited to the atmosphere. Oxidizing atmosphere, for example
・ Atmosphere containing more oxygen molecules (O 2 ) than the atmosphere ・ Atmosphere containing more water vapor than the atmosphere ・ Atmosphere containing oxygen allotropes (O 3 (ozone), oxygen clusters, etc.) ・ Atmosphere containing oxygen compounds ・ Hydroxy The atmosphere may contain a compound having a group (−OH). This matter is common to all the embodiments described later.
　また、この実施形態では、第１電極１１は、アニールしなかった。しかし、第１電極１１は、アニールしないことに限られることはない。第１電極１１をアニールしても良い。第１電極１１をアニールする場合には、
　　・第１電極１１のアニール温度は、第２電極１２よりも低いこと
　　・第１電極１１のアニール時間は、第２電極１２よりも短いこと
　　・第１電極１１のアニールエネルギーは、第２電極１２よりも低いこと
の少なくともいずれか１つを満足することが良い。これにより、第１電極１１の仕事関数の値と第２電極１２の仕事関数の値との差を、大きく保つことができる。 Further, in this embodiment, the first electrode 11 was not annealed. However, the first electrode 11 is not limited to not being annealed. The first electrode 11 may be annealed. When annealing the first electrode 11,
-The annealing temperature of the first electrode 11 is lower than that of the second electrode 12.-The annealing time of the first electrode 11 is shorter than that of the second electrode 12.-The annealing energy of the first electrode 11 is the second electrode 12. It is better to satisfy at least one of the lower than. As a result, the difference between the value of the work function of the first electrode 11 and the value of the work function of the second electrode 12 can be kept large.
　また、この実施形態では、第２電極１２をアニールすることにより、第２電極１２の仕事関数の値を第１電極１１の仕事関数の値よりも大きくしたが、反対に第２電極１２の仕事関数の値を第１電極１１の仕事関数の値よりも小さくすることも可能である。この事項は、後述する全ての実施形態で共通する。 Further, in this embodiment, the work function value of the second electrode 12 is made larger than the work function value of the first electrode 11 by annealing the second electrode 12, but on the contrary, the work function of the second electrode 12 is increased. It is also possible to make the value of the function smaller than the value of the work function of the first electrode 11. This matter is common to all the embodiments described later.
　また、この実施形態では、第２電極１２をアニールしたが、第２電極１２に代えて第１電極１１をアニールすることも可能である。 Further, in this embodiment, the second electrode 12 is annealed, but the first electrode 11 can be annealed instead of the second electrode 12.
第２実施形態
（発電素子：第２例）
　導電性材料の中には、大気に暴露されると、その表面に自然酸化被膜を形成してしまうものがある。例えば、Ｔｉである。Ｔｉは、大気に暴露されると、その表面に自然酸化被膜が形成される。なお、この事項は、第１実施形態を否定するものではない。なぜならば、Ｔｉ膜を基板上に形成した後、例えばロードロックにより、Ｔｉ膜を、大気等の酸化性雰囲気に曝さなければ、自然酸化被膜の形成を抑制できるためである。 2nd Embodiment (Power generation element: 2nd example)
Some conductive materials form a natural oxide film on their surface when exposed to the atmosphere. For example, Ti. When Ti is exposed to the atmosphere, a natural oxide film is formed on its surface. It should be noted that this matter does not deny the first embodiment. This is because the formation of the natural oxide film can be suppressed unless the Ti film is exposed to an oxidizing atmosphere such as the atmosphere after the Ti film is formed on the substrate, for example, by load locking.
　以下、第２実施形態として、第１電極１１及び第２電極１２それぞれに、大気に暴露された際に表面に自然酸化被膜を形成する導電性物質が用いられた場合の例を説明する。 Hereinafter, as the second embodiment, an example in which a conductive substance that forms a natural oxide film on the surface of each of the first electrode 11 and the second electrode 12 is used will be described.
　図６は、この発明の第２実施形態に係る発電素子の一例を示す模式断面図である。図６に示す模式断面は、図１（ａ）に示す模式断面に相当する。 FIG. 6 is a schematic cross-sectional view showing an example of a power generation element according to the second embodiment of the present invention. The schematic cross section shown in FIG. 6 corresponds to the schematic cross section shown in FIG. 1 (a).
　図６に示すように、第２実施形態に係る発電素子１ｂが、第１実施形態に係る発電素子１と異なるところは、第１電極１１の少なくとも第２電極１２と対向する面上には導電性物質の第１酸化被膜１１ｂが有り、第２電極１２の少なくとも第１電極１１と対向する面上には導電性物質の第２酸化被膜１２ｂが有ることである。 As shown in FIG. 6, the power generation element 1b according to the second embodiment is different from the power generation element 1 according to the first embodiment in that it is conductive on at least the surface of the first electrode 11 facing the second electrode 12. The first oxide film 11b of the sex substance is present, and the second oxide film 12b of the conductive substance is present on the surface of the second electrode 12 facing at least the first electrode 11.
　第２酸化被膜１２ｂは、以下の少なくとも１つの状態を取る。
　　ケースＡ：第２酸化被膜１２ｂの酸化数は、第１酸化被膜１１ｂの酸化数よりも大きい。
　　ケースＢ：第２酸化被膜１２ｂの厚さは、第１酸化被膜１１ｂの厚さよりも厚い。　
　　ケースＣ：第２酸化被膜１２ｂは、第１酸化被膜１１ｂの同素変態物を含む。 The second oxide film 12b takes at least one of the following states.
Case A: The oxidation number of the second oxide film 12b is larger than the oxidation number of the first oxide film 11b.
Case B: The thickness of the second oxide film 12b is thicker than the thickness of the first oxide film 11b.
Case C: The second oxide film 12b contains an allotropic transformation of the first oxide film 11b.
　なお、図６には、図面上、最も視認しやすいケースＢが示されている。 Note that FIG. 6 shows the case B, which is the easiest to see in the drawing.
　＜ケースＡ＞
　ケースＡの一例は、第１酸化被膜１１ｂは酸化数（Ｉ）～酸化数（ＩＩ）の酸化物が酸化数（ＩＩＩ）～酸化数（ＩＶ）の酸化物をより多く含み、第２酸化被膜１２ｂは酸化数（ｉｉｉ）～酸化数（ＩＶ）の酸化物が酸化数（Ｉ）～酸化数（ＩＩ）の酸化物をより多く含む場合などの状態が該当する。 <Case A>
In an example of Case A, in the first oxide film 11b, the oxides of the oxidation number (I) to the oxidation number (II) contain more oxides of the oxidation number (III) to the oxidation number (IV), and the second oxide film 12b corresponds to a state in which the oxides of the oxidation number (iii) to the oxidation number (IV) contain more oxides of the oxidation number (I) to the oxidation number (II).
　例えば、導電性物質がＴｉの場合を例に挙げると、第１酸化被膜１１ｂは、Ｔｉ2Ｏ（酸化数（Ｉ））及びＴｉＯ（酸化数（ＩＩ））が、Ｔｉ2Ｏ3（酸化数（ＩＩＩ））及びＴｉＯ2（酸化数（ＩＶ））より多く含み、第２酸化被膜１２ｂは、Ｔｉ2Ｏ3及びＴｉＯ2が、Ｔｉ2Ｏ及びＴｉＯより多く含む、となる。 For example, in the case where the conductive substance is Ti, the first oxide film 11b has Ti 2 O (oxidation number (I)) and TiO (oxidation number (II)) as Ti 2 O 3 (oxidation number (II)). (III)) and TiO 2 (oxidation number (IV)) are contained in a larger amount, and the second oxide film 12b contains more Ti 2 O 3 and TIO 2 than Ti 2 O and TIO.
　Ｔｉは、大気に暴露されると自然酸化被膜を形成するが、Ｔｉの自然酸化被膜の主たる酸化物は、酸化数が低いＴｉ2Ｏ及びＴｉＯと考えることができる。酸化数が低いＴｉ2Ｏ及びＴｉＯに対して、第１実施形態に従ったアニールをすると、アニール温度等の条件にはよるが、第２酸化被膜１２ｂの膜質は、第１酸化被膜１１ｂの膜質よりも、例えば緻密にできる。これは、自然酸化被膜の状態よりも、酸化数が増加したものと考えることができる。 Ti forms a natural oxide film when exposed to the atmosphere, and the main oxides of the natural oxide film of Ti can be considered to be Ti 2 O and Ti O having a low oxidation number. When Ti 2 O and TiO having a low oxidation number are annealed according to the first embodiment, the film quality of the second oxide film 12b is the film quality of the first oxide film 11b, although it depends on the conditions such as the annealing temperature. For example, it can be made more precise. It can be considered that this is because the oxidation number is increased as compared with the state of the natural oxide film.
　例えば、表面に、酸化数が低いＴｉ2Ｏ及びＴｉＯを主たる酸化物として有するＴｉ膜の仕事関数は、Ｔｉそのものの仕事関数に近い。これに対して、表面に、酸化数が高いＴｉ2Ｏ3及びＴｉＯ2を主たる酸化物として有するＴｉ膜の仕事関数は、ＴｉＯ2の仕事関数に近い。これは、例えば、自然酸化被膜であった第２酸化被膜１２ｂのフェルミ準位を、自然酸化被膜のままである第１酸化被膜１１ｂのフェルミ準位から変えることができる、ということである。このことから、第１電極１１と第２電極１２とに、仕事関数の差を持たせることができる。例えば、Ｔｉの仕事関数は、約４．２～４．４ｅＶであり、ＴｉＯ2の仕事関数は、約６．１～６．３ｅＶである。ナノ粒子１４にＡｕに用いたとすると、Ａｕの仕事関数は、約５．４～約５．６ｅＶである。第２電極１２の仕事関数の値は、第１電極１１の仕事関数の値から、ナノ粒子１４の仕事関数の値を超えて変化させることができる。したがって、ケースＡに係る発電素子１ｂは、発電素子として、十分に機能させることができる。 For example, the work function of a Ti film having Ti 2 O having a low oxidation number as a main oxide on the surface is close to the work function of Ti itself. In contrast, the surface, the work function of Ti film having oxidation number higher Ti 2 O 3 and TiO 2 as the main oxides, close to the work function of the TiO 2. This means that, for example, the Fermi level of the second oxide film 12b, which was a natural oxide film, can be changed from the Fermi level of the first oxide film 11b, which remains the natural oxide film. From this, it is possible to give a difference in work function between the first electrode 11 and the second electrode 12. For example, the work function of Ti is about 4.2 to 4.4 eV, and the work function of TiO 2 is about 6.1 to 6.3 eV. Assuming that the nanoparticles 14 are used for Au, the work function of Au is about 5.4 to about 5.6 eV. The value of the work function of the second electrode 12 can be changed from the value of the work function of the first electrode 11 beyond the value of the work function of the nanoparticles 14. Therefore, the power generation element 1b according to the case A can sufficiently function as a power generation element.
　＜ケースＢ＞
　ケースＢは、第１電極１１及び第２電極１２の厚さが実質的に同じならば、酸化被膜が厚ければ厚いほど、導電性物質に占める導電性物質の酸化物の割合が増え、電極の仕事関数は、導電性物質の酸化物の仕事関数に近づく、というものである。自然酸化被膜を、第１実施形態に従ったアニールをすると、アニール温度等の条件及び導電性物質の種類にはよるが、酸化被膜の厚さを、酸化数は同じままで厚くすることもできる。第１酸化被膜１１ｂの酸化数と第２酸化被膜１２ｂの酸化数とが同じであったとしても、例えば第２酸化被膜１２ｂの厚さが第１酸化被膜１１ｂの厚さよりも厚ければ、第２電極１２の仕事関数は、導電性物質の仕事関数に近づく。このことから、第２電極１２の仕事関数の値は、第１電極１１の仕事関数の値から、ナノ粒子１４の仕事関数の値を超えて変化させることができる。したがって、ケースＢに係る発電素子１ｂも、発電素子として、十分に機能させることができる。 <Case B>
In case B, if the thicknesses of the first electrode 11 and the second electrode 12 are substantially the same, the thicker the oxide film, the larger the ratio of the oxide of the conductive substance to the conductive substance, and the electrode. The work function of is close to the work function of oxides of conductive materials. When the natural oxide film is annealed according to the first embodiment, the thickness of the oxide film can be increased with the same oxidation number, although it depends on the conditions such as the annealing temperature and the type of the conductive substance. .. Even if the oxidation number of the first oxide film 11b and the oxidation number of the second oxide film 12b are the same, for example, if the thickness of the second oxide film 12b is thicker than the thickness of the first oxide film 11b, the first oxide film The work function of the two electrodes 12 approaches the work function of the conductive material. From this, the value of the work function of the second electrode 12 can be changed from the value of the work function of the first electrode 11 beyond the value of the work function of the nanoparticles 14. Therefore, the power generation element 1b according to the case B can also be sufficiently functioned as a power generation element.
　＜ケースＣ＞
　ケースＣは、第１酸化被膜１１ｂと第２酸化被膜１２ｂとが同じ酸化物であっても、第２酸化被膜１２ｂが同素変態していれば、第２酸化被膜１２ｂの仕事関数を、第１酸化被膜１１ｂの仕事関数から変えることができる、というものである。第２酸化被膜１２ｂをアニールすることで、第２酸化被膜１２ｂを、第１酸化被膜１１ｂから同素変態させることもできる。同素変態の一例は、「結晶構造の違い」である。ＴｉＯ2の場合を例に挙げると、ＴｉＯ2には、ルチル型、ブルッカイト型及びアナターゼ型の結晶型がある。これらは、ＴｉＯ2の同素変態物である。ＴｉＯ2は、アニール温度が、例えば６５０～７５０℃であるとアナターゼ型となり、アニール温度が、例えば７５０℃を超えるとルチル型となる。第２酸化被膜１２ｂを、第１酸化被膜１１ｂの同素変態物とすることで、第２電極１２の仕事関数の値は、第１電極１１の仕事関数の値から、ナノ粒子１４の仕事関数の値を超えて変化させることができる。 <Case C>
In case C, even if the first oxide film 11b and the second oxide film 12b are the same oxide, if the second oxide film 12b is allotropically transformed, the work function of the second oxide film 12b can be determined. It can be changed from the work function of the monooxide film 11b. By annealing the second oxide film 12b, the second oxide film 12b can be allotropically transformed from the first oxide film 11b. An example of allotropic transformation is "difference in crystal structure". Taking the case of TiO 2 as an example, TiO 2 has a rutile type, a brookite type, and an anatase type crystal type. These are allotropic transformations of TiO 2. TiO 2 becomes anatase type when the annealing temperature is, for example, 650 to 750 ° C., and becomes rutile type when the annealing temperature exceeds, for example, 750 ° C. By making the second oxide film 12b an allotropic transformation of the first oxide film 11b, the value of the work function of the second electrode 12 is the work function of the nanoparticles 14 from the value of the work function of the first electrode 11. Can be varied beyond the value of.
　また、Ｔｉも同素変態する。Ｔｉの結晶構造は、室温（２５℃）では細密立方格子（ｈｃｐ）であるが、例えばアニール温度８７０～８９０℃でアニールすると、体心立方格子（ｂｃｃ）へと同素変態する。 Also, Ti also undergoes allotropic transformation. The crystal structure of Ti is a fine cubic lattice (hcp) at room temperature (25 ° C.), but when it is annealed at an annealing temperature of 870 to 890 ° C., it undergoes an allotropic transformation into a body-centered cubic lattice (bcc).
　また、Ｚｒ（ジルコニウム）も同素変態する。Ｚｒの結晶構造は、Ｔｉ同様に室温（２５℃）では細密立方格子（ｈｃｐ）であるが、例えばアニール温度８５０～８７０℃でアニールすると、体心立方格子（ｂｃｃ）へと同素変態する。 Zr (zirconium) also undergoes allotropic transformation. The crystal structure of Zr is a fine cubic lattice (hcp) at room temperature (25 ° C.) like Ti, but when it is annealed at an annealing temperature of 850 to 870 ° C., it is allotropically transformed into a body-centered cubic lattice (bcc).
　また、例えば、アナターゼ型ＴｉＯ2は、約３．１～３．３ｅＶのバンドギャップを有するｎ型半導体である。これゆえ、アナターゼ型ＴｉＯ2は、例えば、紫外線照射による光触媒活性を示す。 Further, for example, anatase-type TiO 2 is an n-type semiconductor having a bandgap of about 3.1 to 3.3 eV. Therefore, anatase-type TiO 2 exhibits photocatalytic activity by irradiation with ultraviolet rays, for example.
　図７は、第１電極、第２電極及びナノ粒子の仕事関数の関係を示す図である。 FIG. 7 is a diagram showing the relationship between the work functions of the first electrode, the second electrode, and the nanoparticles.
　図７に示すように、アニールにより、導電体を半導体とすると、第２電極１２の仕事関数を、大きく第１電極１１の仕事関数から異ならせることが可能である。 As shown in FIG. 7, when the conductor is a semiconductor by annealing, the work function of the second electrode 12 can be largely different from the work function of the first electrode 11.
　なお、この実施形態では、第１酸化被膜１１ｂ及びアニールする前の第２酸化被膜１２ｂは、自然酸化被膜としたが、自然酸化被膜に限られることはない。第１酸化被膜１１ｂ及びアニールする前の第２酸化被膜１２ｂは、化学的に酸化した酸化被膜であっても良い。このことは、後述する全ての実施形態で共通する。 In this embodiment, the first oxide film 11b and the second oxide film 12b before annealing are natural oxide films, but the present invention is not limited to the natural oxide film. The first oxide film 11b and the second oxide film 12b before annealing may be a chemically oxidized oxide film. This is common to all embodiments described below.
　また、ケースＡ～ケースＣは重複することが可能であり、アニールを酸化性雰囲気中で行い、このアニールにより、
　（１）第２酸化被膜１２ｂの酸化数を、第１酸化被膜１１ｂの酸化数よりも増加させること
　（２）第２酸化被膜１２ｂの厚さを、第１酸化被膜１１ｂの厚さよりも厚くすること
　（３）第２酸化被膜１２ｂを、第１酸化被膜１１ｂから同素変態させること
　上記（１）～（３）の少なくとも１つが行われれば良い。 In addition, cases A to C can overlap, and annealing is performed in an oxidizing atmosphere, and by this annealing,
(1) Increase the oxidation number of the second oxide film 12b from the oxidation number of the first oxide film 11b (2) Make the thickness of the second oxide film 12b thicker than the thickness of the first oxide film 11b. (3) Passivation of the second oxide film 12b from the first oxide film 11b At least one of the above (1) to (3) may be performed.
　また、この実施形態では、同素変態の一例として、「結晶構造の違い」を説明した。同素変態の別の例としては、「結晶方位の違い」を挙げることができる。金属及び半導体では、結晶面によって電子密度が異なる。結晶面によって電子密度が異なる結果、金属及び半導体では、結晶方位によって仕事関数が変化する。したがって、同素変態の例としては、「結晶構造の違い」のほか、「結晶方位の違い」であっても良い。 Further, in this embodiment, "difference in crystal structure" was explained as an example of allotropic transformation. Another example of allotropic transformation is "difference in crystal orientation". In metals and semiconductors, the electron density differs depending on the crystal plane. As a result of the difference in electron density depending on the crystal plane, the work function of metals and semiconductors changes depending on the crystal orientation. Therefore, as an example of allotropic transformation, in addition to "difference in crystal structure", "difference in crystal orientation" may be used.
　また、導電性物質を同素変態させる場合には、熱アニール、レーザアニール、光アニールのほか、導電性物質に対して高い圧力を印加することも有効である。同素変態のうち、例えば「結晶構造の変化」及び「結晶方位の変化」は、「圧力の印加」でも起こるためである。 In addition, when transforming a conductive substance into allotropics, it is effective to apply a high pressure to the conductive substance in addition to thermal annealing, laser annealing, and photoannealation. This is because, among allotropic transformations, for example, "change in crystal structure" and "change in crystal orientation" also occur in "application of pressure".
　また、導電性物質を、「圧力の印加」によって同素変態させる場合には、アニールとして、別途、熱等を印加したりせず、「圧力の印加」を単独で行うことも可能である。 Further, when the conductive substance is allotropically transformed by "applying pressure", it is also possible to perform "applying pressure" alone as annealing without separately applying heat or the like.
第３実施形態
（電極の仕事関数の制御方法）
　第１実施形態及び第２実施形態は、第２電極１２を、アニールにより酸化する例を示した。アニールは、酸化する例に限られることはない。例えば、第１電極１１又は第２電極１２の一方をアニールにより還元することで、第２電極１２の仕事関数の値を、第１電極１１の仕事関数からナノ粒子１４の仕事関数の値を超えて変化させる、又は第１電極１１の仕事関数の値を第２電極１２からナノ粒子１４の仕事関数の値を超えて変化させることもできる。この場合のアニールは、還元性雰囲気中で行われる。 Third Embodiment (Method of controlling work function of electrodes)
The first embodiment and the second embodiment showed an example in which the second electrode 12 is oxidized by annealing. Annealing is not limited to the case of oxidation. For example, by reducing one of the first electrode 11 and the second electrode 12 by annealing, the value of the work function of the second electrode 12 exceeds the value of the work function of the nanoparticles 14 from the work function of the first electrode 11. Or the value of the work function of the first electrode 11 can be changed from the second electrode 12 beyond the value of the work function of the nanoparticles 14. Annealing in this case is performed in a reducing atmosphere.
（発電素子：第３例）
　図８は、この発明の第３実施形態に係る発電素子の一例を示す模式断面図である。図８に示す模式断面は、図１（ａ）に示す模式断面に相当する。 (Power generation element: 3rd example)
FIG. 8 is a schematic cross-sectional view showing an example of the power generation element according to the third embodiment of the present invention. The schematic cross section shown in FIG. 8 corresponds to the schematic cross section shown in FIG. 1 (a).
　図８に示すように、第３実施形態に係る発電素子１ｃが、第１実施形態に係る発電素子１と異なるところは、第１電極１１の少なくとも第２電極１２と対向する面上には導電性物質の還元層１１ｃが有ることである。この実施形態では、第２電極１２の少なくとも第１電極１１と対向する面上には導電性物質が有る。導電性物質の一例は、チタン酸化物である。還元層１１ｃの一例は、Ｔｉである。 As shown in FIG. 8, the power generation element 1c according to the third embodiment is different from the power generation element 1 according to the first embodiment in that the first electrode 11 is conductive on at least the surface facing the second electrode 12. There is a reducing layer 11c of the sex substance. In this embodiment, there is a conductive substance on the surface of the second electrode 12 facing at least the first electrode 11. An example of a conductive substance is titanium oxide. An example of the reduction layer 11c is Ti.
　図９は、第１電極、第２電極及びナノ粒子の仕事関数の関係を示す図である。 FIG. 9 is a diagram showing the relationship between the work functions of the first electrode, the second electrode, and the nanoparticles.
　チタン酸化物を還元すると、Ｔｉとなる。このため、図９に示すように、仕事関数を小さくすることができる。 When titanium oxide is reduced, it becomes Ti. Therefore, as shown in FIG. 9, the work function can be made small.
第４実施形態
（発電素子：第４例）
　図１０は、この発明の第４実施形態に係る発電素子の一例を示す模式断面図である。図１０に示す模式断面は、図１（ａ）に示す模式断面に相当する。 Fourth Embodiment (Power generation element: Fourth example)
FIG. 10 is a schematic cross-sectional view showing an example of a power generation element according to a fourth embodiment of the present invention. The schematic cross section shown in FIG. 10 corresponds to the schematic cross section shown in FIG. 1 (a).
　第４実施形態は、第２実施形態に準ずる例であり、第１電極１１の少なくとも第２電極１２と対向する面上に第１酸化被膜１１ｂを有し、第２電極１２の少なくとも第１電極１１と対向する面上に第２酸化被膜１２ｂを有する例である。 The fourth embodiment is an example according to the second embodiment, in which the first oxide film 11b is provided on the surface of the first electrode 11 facing at least the second electrode 12, and at least the first electrode of the second electrode 12 is provided. This is an example in which the second oxide film 12b is provided on the surface facing the 11.
　第４実施形態に係る発電素子１ｄが、第２実施形態に係る発電素子１ｂと異なるところは、第１酸化被膜１１ｂがアニールにより還元され、第１酸化被膜１１ｂの表面領域に還元層１１ｃが有ることである。また、第２酸化被膜１２ｂは、自然酸化被膜又は化学的に酸化した酸化被膜である。 The difference between the power generation element 1d according to the fourth embodiment and the power generation element 1b according to the second embodiment is that the first oxide film 11b is reduced by annealing, and the reduction layer 11c is present in the surface region of the first oxide film 11b. That is. The second oxide film 12b is a natural oxide film or a chemically oxidized oxide film.
　第１酸化被膜１１ｂは、以下の少なくとも１つの状態を取る。
　　ケースＤ：第１酸化被膜１１ｂの酸化数は、第２酸化被膜１２ｂの酸化数よりも小さい。
　　ケースＥ：第１酸化被膜１１ｂの厚さは、第２酸化被膜１２ｂの厚さよりも薄い。　
　　ケースＦ：第１酸化被膜１１ｂは、第２酸化被膜１２ｂの同素変態物を含む。 The first oxide film 11b takes at least one of the following states.
Case D: The oxidation number of the first oxide film 11b is smaller than the oxidation number of the second oxide film 12b.
Case E: The thickness of the first oxide film 11b is thinner than the thickness of the second oxide film 12b.
Case F: The first oxide film 11b contains an allotropic transformation of the second oxide film 12b.
　なお、図１０には、図面上、最も視認しやすいケースＥが示されている。図１０に示す例では、第１酸化被膜１１ｂの表面領域に還元層１１ｃが形成されており、還元層１１ｃにより、第１酸化被膜１１ｂの厚さが減じられている。第１酸化被膜１１ｂが還元層１１ｃにより消失することもある。消失した場合は、第１酸化被膜１１ｂは無くなるということであり、構造的には図１（ａ）に示した構造と、同様の構造となる。 Note that FIG. 10 shows the case E, which is the easiest to see in the drawing. In the example shown in FIG. 10, the reducing layer 11c is formed in the surface region of the first oxide film 11b, and the thickness of the first oxide film 11b is reduced by the reducing layer 11c. The first oxide film 11b may disappear due to the reducing layer 11c. When it disappears, the first oxide film 11b disappears, and the structure is structurally similar to that shown in FIG. 1A.
　ケースＤ～ケースＦは重複することが可能であり、アニールを還元性雰囲気中で行い、このアニールにより、
　（４）第１酸化被膜１１ｂの酸化数を、第２酸化被膜１２ｂの酸化数よりも減少させる
　（５）第１酸化被膜１１ｂの厚さを、第２酸化被膜１２ｂの厚さよりも薄くする
　（６）第１酸化被膜１１ｂ、第２酸化被膜１２ｂから同素変態させる
　上記（４）～（６）の少なくとも１つが行われれば良い。 Cases D to F can overlap, and annealing is performed in a reducing atmosphere, and by this annealing,
(4) Decrease the oxidation number of the first oxide film 11b from the oxidation number of the second oxide film 12b (5) Make the thickness of the first oxide film 11b thinner than the thickness of the second oxide film 12b (5) 6) Passivation transformation from the first oxide film 11b and the second oxide film 12b At least one of the above (4) to (6) may be performed.
　還元は、酸化の反対である、と考えて良い。このため、ケースＤ～ケースＦは、以下のように読み替えることが可能である。
　ケースＤ１：第２酸化被膜１２ｂの酸化数は、第１酸化被膜１１ｂの酸化数よりも大きい。
　ケースＥ１：第２酸化被膜１２ｂの厚さは、第１酸化被膜１１ｂの厚さよりも厚い。　
　ケースＦ１：第２酸化被膜１２ｂは、第１酸化被膜１１ｂの同素変態物を含む。 Reduction can be thought of as the opposite of oxidation. Therefore, Case D to Case F can be read as follows.
Case D1: The oxidation number of the second oxide film 12b is larger than the oxidation number of the first oxide film 11b.
Case E1: The thickness of the second oxide film 12b is thicker than the thickness of the first oxide film 11b.
Case F1: The second oxide film 12b contains an allotropic transformation of the first oxide film 11b.
　ケースＤ１～ケースＦ１は、第２実施形態のケースＡ～ケースＣと同じ関係である。したがって、第４実施形態においては、第２実施形態の説明を引用し、その具体的な説明は省略する。 Cases D1 to F1 have the same relationship as cases A to C of the second embodiment. Therefore, in the fourth embodiment, the description of the second embodiment will be quoted, and the specific description thereof will be omitted.
第５実施形態
（電極の仕事関数の制御方法）
　アニールは、酸化性雰囲気中又は還元性雰囲気中で行うことに限られることはなく、減圧下又は不活性雰囲気中で行うこともできる。アニールを減圧下又は不活性雰囲気中で行うことにより、第２電極１２は、例えば、第１電極１１から同素変態する。同素変態は、第２電極１２の全体で生じなくても、第２電極１２の一部に生じれば良い。 Fifth Embodiment (Method of controlling work function of electrode)
Annealing is not limited to being carried out in an oxidizing atmosphere or a reducing atmosphere, but can also be carried out under reduced pressure or in an inert atmosphere. By performing the annealing under reduced pressure or in an inert atmosphere, the second electrode 12 undergoes allotropic transformation from, for example, the first electrode 11. The allotropic transformation does not have to occur in the entire second electrode 12, but may occur in a part of the second electrode 12.
（発電素子：第５例）
　図１１は、この発明の第５実施形態に係る発電素子の一例を示す模式断面図である。図１１に示す模式断面は、図１（ａ）に示す模式断面に相当する。 (Power generation element: 5th example)
FIG. 11 is a schematic cross-sectional view showing an example of the power generation element according to the fifth embodiment of the present invention. The schematic cross section shown in FIG. 11 corresponds to the schematic cross section shown in FIG. 1 (a).
　図１１に示すように、第５実施形態に係る発電素子１ｅが、第１実施形態に係る発電素子１と異なるところは、第２電極１２は、例えば、第１電極１１から同素変態していることである。 As shown in FIG. 11, the power generation element 1e according to the fifth embodiment is different from the power generation element 1 according to the first embodiment in that the second electrode 12 is, for example, allotropically transformed from the first electrode 11. It is that you are.
　同素変態の例は、例えば第２実施形態で説明したように、「結晶構造の違い」、「結晶方位の違い」等である。１つの例として、図１１には、第１電極１１の結晶構造と、第２電極１２の結晶構造との違いを、模式的に示している。発電素子１ｅでは、第２電極１２自体が、第１電極１１から同素変態している。発電素子１ｅのように、第２電極１２自体が、第１電極１１から同素変態していても良い。 Examples of allotropic transformation are, for example, "difference in crystal structure", "difference in crystal orientation", etc., as described in the second embodiment. As one example, FIG. 11 schematically shows the difference between the crystal structure of the first electrode 11 and the crystal structure of the second electrode 12. In the power generation element 1e, the second electrode 12 itself is allotropically transformed from the first electrode 11. Like the power generation element 1e, the second electrode 12 itself may be allotropically transformed from the first electrode 11.
　なお、第２電極１２の全体が、第１電極１１から同素変態していなくても、第２電極１２の一部が、第１電極１１から同素変態していれば良い。即ち、第２電極１２は、前記第１電極の同素変態物を含んでいれば良い。 Even if the entire second electrode 12 is not allotropically transformed from the first electrode 11, a part of the second electrode 12 may be allotropically transformed from the first electrode 11. That is, the second electrode 12 may contain an allotropic transformation product of the first electrode.
第６実施形態
（電極の仕事関数の制御方法）
　アニールは、活性雰囲気中で行うことできる。アニールを活性雰囲気中で行うことにより、第２電極１２の少なくとも第１電極１１と対向する面は、表面改質される。 Sixth Embodiment (Method of controlling work function of electrode)
Annealing can be performed in an active atmosphere. By performing the annealing in an active atmosphere, at least the surface of the second electrode 12 facing the first electrode 11 is surface-modified.
（発電素子：第６例）
　図１２は、この発明の第６実施形態に係る発電素子の一例を示す模式断面図である。図１２に示す模式断面は、図１（ａ）に示す模式断面に相当する。 (Power generation element: 6th example)
FIG. 12 is a schematic cross-sectional view showing an example of the power generation element according to the sixth embodiment of the present invention. The schematic cross section shown in FIG. 12 corresponds to the schematic cross section shown in FIG. 1 (a).
　図１２に示すように、第６実施形態に係る発電素子１ｆが、第１実施形態に係る発電素子１と異なるところは、第２電極１２が表面改質され、第２電極１２の少なくとも第１電極１１と対向する面に、表面改質層１２ｄが設けられていることである。 As shown in FIG. 12, the power generation element 1f according to the sixth embodiment is different from the power generation element 1 according to the first embodiment in that the second electrode 12 is surface-modified and at least the first of the second electrodes 12 is formed. The surface modification layer 12d is provided on the surface facing the electrode 11.
　この明細書で述べる表面改質は、第２電極１２の導電性物質に、表面改質物質を拡散又は付着させることである。表面改質の例は、窒化、ホウ化、浸炭等である。 The surface modification described in this specification is to diffuse or adhere the surface modification substance to the conductive substance of the second electrode 12. Examples of surface modification are nitriding, boring, carburizing and the like.
　このように、第２電極１２を表面改質することでも、第２電極１２の少なくとも第１電極１１と対向する面の状態を、第１電極１１の少なくとも第２電極１２と対向する面の状態と異ならせることができる。したがって、第１実施形態と同様に、第１電極１１及び第２電極１２のそれぞれが同じ導電性物質でありながらも、第１電極１１の仕事関数の値φＫ、第２電極１２の仕事関数の値φＡ及びナノ粒子１４の仕事関数の値φＮの関係を、
　　φＫ　＜　φＮ　＜　φＡ
とすることができる。 By surface-modifying the second electrode 12 in this way, the state of the surface of the second electrode 12 facing at least the first electrode 11 can be changed to the state of the surface of the first electrode 11 facing at least the second electrode 12. Can be different from. Therefore, as in the first embodiment, although the first electrode 11 and the second electrode 12 are each the same conductive substance, the work function value φK of the first electrode 11 and the work function of the second electrode 12 The relationship between the value φA and the work function value φN of the nanoparticles 14
φK <φN <φA
Can be.
　また、導電性物質の表面改質と、導電性物質の同素変態とを一緒に生じさせることも可能である。 It is also possible to cause surface modification of the conductive substance and allotropic transformation of the conductive substance together.
第７実施形態
（発電素子：第７例）
　図１３は、この発明の第７実施形態に係る発電素子の一例を示す模式断面図である。図１３に示す模式断面は、図１（ａ）に示す模式断面に相当する。 Seventh Embodiment (Power generation element: Seventh example)
FIG. 13 is a schematic cross-sectional view showing an example of the power generation element according to the seventh embodiment of the present invention. The schematic cross section shown in FIG. 13 corresponds to the schematic cross section shown in FIG. 1 (a).
　図１３に示すように、第７実施形態に係る発電素子１ｇが、第１実施形態に係る発電素子１と異なるところは、支持部２３が無く、第１フレキシブル基板２１ａと第２フレキシブル基板２２ａとが、第１電極１１及び第２電極１２の周囲近傍において、結合されていることである。結合は、例えば、接着剤を用いた接着で良い。発電素子１ｇのように、支持部２３を、発電素子の構造から省略することも可能である。 As shown in FIG. 13, the difference between the power generation element 1g according to the seventh embodiment and the power generation element 1 according to the first embodiment is that there is no support portion 23, and the first flexible substrate 21a and the second flexible substrate 22a Is coupled in the vicinity of the periphery of the first electrode 11 and the second electrode 12. The bonding may be, for example, bonding using an adhesive. It is also possible to omit the support portion 23 from the structure of the power generation element, as in the case of the power generation element 1g.
　発電素子１ｇによれば、支持部２３が無いので、発電素子の部品点数を削減でき、発電素子の製造コストの、更なる抑制に有用である。 According to the power generation element 1g, since there is no support portion 23, the number of parts of the power generation element can be reduced, which is useful for further suppressing the manufacturing cost of the power generation element.
　また、支持部２３が無いので、支持部２３に起因した電極間ギャップＧＥの「発電素子間ばらつき」を抑制でき、発電素子の特性ばらつきの低減にも貢献できる。 Further, since there is no support portion 23, it is possible to suppress "variation between power generation elements" of the gap GE between electrodes caused by the support portion 23, and it is possible to contribute to reduction of characteristic variation of power generation elements.
　なお、この実施形態では、基板を、第１フレキシブル基板２１ａと第２フレキシブル基板２２ａとしたが、基板はフレキシブルな基板に限られるものではない。例えば、発電素子１ｇは、窪みを有した強固な基板に、第１電極１１及び第２電極１２の少なくとも１つを形成し、２つの基板を結合させた構造であっても良い。 In this embodiment, the substrates are the first flexible substrate 21a and the second flexible substrate 22a, but the substrate is not limited to the flexible substrate. For example, the power generation element 1g may have a structure in which at least one of the first electrode 11 and the second electrode 12 is formed on a strong substrate having a recess, and the two substrates are bonded to each other.
　なお、発電素子１ｇは、上述した全ての実施形態において、適用可能である。 Note that 1 g of the power generation element can be applied in all the above-described embodiments.
第８実施形態
（発電素子の製造方法）
　図１４は、この発明の第８実施形態に係る発電素子の製造方法の一例を示す流れ図である。 Eighth Embodiment (Manufacturing method of power generation element)
FIG. 14 is a flow chart showing an example of a method for manufacturing a power generation element according to an eighth embodiment of the present invention.
　図１４に示すように、まず、第１基板２１上に第１電極１１を形成する（ＳＴ．１）。次に、第２基板２２上に、第１電極１１と同じ導電性物質である第２電極１２を形成する（ＳＴ．２）。ＳＴ．１及びＳＴ．２は、２つの工程に分ける必要はない。例えば、基板上に導電性物質の膜を形成し、導電性物質の膜を形成した基板を２つ以上に分割して、第１電極１１を有した第１基板２１と第２電極１２を有した第２基板２２とを形成することも可能である。この明細書では、ＳＴ．１及びＳＴ．２は、２つの工程に分ける場合と、１つの工程とする場合との双方を包含する、と定義する。 As shown in FIG. 14, first, the first electrode 11 is formed on the first substrate 21 (ST.1). Next, the second electrode 12, which is the same conductive substance as the first electrode 11, is formed on the second substrate 22 (ST.2). ST. 1 and ST. 2 does not need to be divided into two steps. For example, a film of a conductive substance is formed on the substrate, and the substrate on which the film of the conductive substance is formed is divided into two or more to have a first substrate 21 having a first electrode 11 and a second electrode 12. It is also possible to form the second substrate 22. In this specification, ST. 1 and ST. 2 is defined to include both the case of dividing into two steps and the case of making one step.
　次に、第２電極１２をアニールし、第２電極１２の仕事関数を、第１電極１１の仕事関数から変化させる（ＳＴ．３）。このアニールは、上述した実施形態で説明したアニールが用いられる。アニール方法は、熱アニール、レーザアニール及び光アニールの少なくとも１つを選ぶことができ、これらのアニール方法を、様々に組み合わせることも可能である。 Next, the second electrode 12 is annealed, and the work function of the second electrode 12 is changed from the work function of the first electrode 11 (ST.3). For this annealing, the annealing described in the above-described embodiment is used. The annealing method can be selected from at least one of thermal annealing, laser annealing and optical annealing, and these annealing methods can be combined in various ways.
　次に、第１電極１１と第２電極１２とを、ギャップＧを介して対向させる（ＳＴ．４）。 Next, the first electrode 11 and the second electrode 12 are opposed to each other via the gap G (ST.4).
　次に、ナノ粒子１４をギャップＧ内に導入する（ＳＴ．５）。これにより、ナノ粒子１４を含む中間部１３が、ギャップＧ内に形成される。ナノ粒子１４は、第１電極１１の仕事関数と第２電極１２の変化された仕事関数との間の仕事関数を有するものが選ばれる。ナノ粒子１４のギャップＧ内への導入方法は、例えば、孔を介した孔導入法、毛細管現象を利用したスリット導入法等を用いることができる。孔導入法の一例は、第１電極１１又は第２電極１２又は支持部２３に注入孔を形成し、形成した注入孔を介して、例えば、溶媒１５に分散されたナノ粒子１４を、ギャップＧ内へ導入する。導入後、注入孔は封止される。スリット導入法の一例は、支持部２３間にギャップＧに通じる細いスリットを形成しておき、形成したスリットを介し、毛細管現象を利用して、例えば、溶媒１５に分散されたナノ粒子１４を、ギャップＧ内へ導入する。導入後、スリットは封止される。 Next, the nanoparticles 14 are introduced into the gap G (ST.5). As a result, the intermediate portion 13 containing the nanoparticles 14 is formed in the gap G. The nanoparticles 14 are selected to have a work function between the work function of the first electrode 11 and the changed work function of the second electrode 12. As a method for introducing the nanoparticles 14 into the gap G, for example, a hole introduction method through holes, a slit introduction method utilizing a capillary phenomenon, or the like can be used. As an example of the hole introduction method, an injection hole is formed in the first electrode 11, the second electrode 12, or the support portion 23, and the nanoparticles 14 dispersed in the solvent 15 are formed through the formed injection hole, for example, in the gap G. Introduce inside. After introduction, the injection holes are sealed. As an example of the slit introduction method, a thin slit leading to the gap G is formed between the support portions 23, and the nanoparticles 14 dispersed in the solvent 15 are used, for example, by utilizing the capillary phenomenon through the formed slit. Introduce into gap G. After introduction, the slits are sealed.
　この発明の上述した実施形態に係る発電素子１、１ｂ～１ｇは、図１４に示すような流れで製造することができる。 The power generation elements 1, 1b to 1 g according to the above-described embodiment of the present invention can be manufactured in the flow as shown in FIG.
　また、この実施形態に係る発電素子の製造方法は、第２電極１２の表面上に、メッキ被膜、堆積膜等のような別の導電性物質膜を形成するのではなく、第２電極１２の少なくとも第１電極１１と対向する面の状態を、第１電極１１の少なくとも第２電極１２と対向する面の状態を異ならせるものである。例えば、この実施形態に係る発電素子の製造方法は、第２電極１２の少なくとも第１電極１１と対向する面を、
　　・酸化する
　　・還元する
　　・同素変態させる
　　・表面改質する
ものである。即ち、別の導電性物質の膜を付着させるのではなくて、第２電極１２自身が持つ導電性物質を利用して、第２電極１２の仕事関数を、第１電極１１の仕事関数から変化させる。このため、例えば、別の導電性物質の膜を付着させる場合と比較して、第２電極１２の厚さのばらつきを小さくでき、発電素子の特性ばらつきの低減にも有効である。 Further, in the method for manufacturing a power generation element according to this embodiment, instead of forming another conductive substance film such as a plating film, a deposited film, etc. on the surface of the second electrode 12, the second electrode 12 is used. At least the state of the surface facing the first electrode 11 is different from the state of the surface of the first electrode 11 facing at least the second electrode 12. For example, in the method for manufacturing a power generation element according to this embodiment, a surface of the second electrode 12 facing at least the first electrode 11 is formed.
・ Oxidizes ・ Reduces ・ Allotropic transformation ・ Surface modification. That is, the work function of the second electrode 12 is changed from the work function of the first electrode 11 by using the conductive substance of the second electrode 12 itself, instead of adhering a film of another conductive substance. Let me. Therefore, for example, the variation in the thickness of the second electrode 12 can be reduced as compared with the case where a film of another conductive substance is attached, which is also effective in reducing the variation in the characteristics of the power generation element.
第９実施形態
（電子機器）
　上述した実施形態のそれぞれにおいて説明した発電素子は、例えば電子機器に搭載することが可能である。以下、電子機器の実施形態のいくつかを説明する。 Ninth Embodiment (electronic device)
The power generation element described in each of the above-described embodiments can be mounted on, for example, an electronic device. Hereinafter, some embodiments of the electronic device will be described.
　図１５（ａ）～図１５（ｄ）は、発電素子を備えた電子機器の例を示す模式ブロック図である。図１５（ｅ）～図１５（ｈ）は、発電素子を含む発電装置を備えた電子機器の例を示す模式ブロック図である。 15 (a) to 15 (d) are schematic block diagrams showing an example of an electronic device provided with a power generation element. 15 (e) to 15 (h) are schematic block diagrams showing an example of an electronic device including a power generation device including a power generation element.
　図１５（ａ）に示すように、電子機器（エレクトリックプロダクト）５００は、電子部品（エレクトロニックコンポーネント）５０１と、主電源５０２と、補助電源５０３と、を備えている。電子機器５００及び電子部品５０１のそれぞれは、電気的な機器(エレクトリカルデバイス)である。 As shown in FIG. 15A, the electronic device (electric product) 500 includes an electronic component (electronic component) 501, a main power source 502, and an auxiliary power source 503. Each of the electronic device 500 and the electronic component 501 is an electrical device (electrical device).
　電子部品５０１は、主電源５０２を電源に用いて駆動される。電子部品５０１の例としては、例えば、ＣＰＵ、モーター、センサ端末、及び照明等を挙げることができる。電子部品５０１が、例えばＣＰＵである場合、電子機器５００には、内蔵されたマスター（ＣＰＵ）によって制御可能な電子機器が含まれる。電子部品５０１が、例えば、モーター、センサ端末、及び照明等の少なくとも１つを含む場合、電子機器５００には、外部にあるマスター、あるいは人によって制御可能な電子機器が含まれる。 The electronic component 501 is driven by using the main power supply 502 as a power source. Examples of the electronic component 501 include a CPU, a motor, a sensor terminal, lighting, and the like. When the electronic component 501 is, for example, a CPU, the electronic device 500 includes an electronic device that can be controlled by a built-in master (CPU). When the electronic component 501 includes, for example, at least one of a motor, a sensor terminal, a lighting, and the like, the electronic device 500 includes an external master, or an electronic device that can be controlled by a person.
　主電源５０２は、例えば電池である。電池には、充電可能な電池も含まれる。主電源５０２のプラス端子（＋）は、電子部品５０１のＶｃｃ端子（Ｖｃｃ）と電気的に接続される。主電源５０２のマイナス端子（－）は、電子部品５０１のＧＮＤ端子（ＧＮＤ）と電気的に接続される。 The main power source 502 is, for example, a battery. Batteries also include rechargeable batteries. The positive terminal (+) of the main power supply 502 is electrically connected to the Vcc terminal (Vcc) of the electronic component 501. The negative terminal (-) of the main power supply 502 is electrically connected to the GND terminal (GND) of the electronic component 501.
　補助電源５０３は、発電素子である。発電素子は、例えば、実施形態のそれぞれにおいて説明した発電素子１、１ｂ～１ｇの少なくとも１つを含む。以下、発電素子１、１ｂ～１ｇを総称して、発電素子１という。発電素子１のアノード（例えば第１電極１１）は、電子部品５０１のＧＮＤ端子（ＧＮＤ）、又は主電源５０２のマイナス端子（－）、又はＧＮＤ端子（ＧＮＤ）とマイナス端子（－）とを接続する配線と、電気的に接続される。発電素子１のカソード（例えば第２電極１２）は、電子部品５０１のＶｃｃ端子（Ｖｃｃ）、又は主電源５０２のプラス端子（＋）、又はＶｃｃ端子（Ｖｃｃ）とプラス端子（＋）とを接続する配線と、電気的に接続される。電子機器５００において、補助電源５０３は、例えば主電源５０２と併用され、主電源５０２をアシストするための電源や、主電源５０２の容量が切れた場合、主電源５０２をバックアップするための電源として使うことができる。主電源５０２が充電可能な電池である場合には、補助電源５０３は、さらに、電池を充電するための電源としても使うことができる。 The auxiliary power supply 503 is a power generation element. The power generation element includes, for example, at least one of the power generation elements 1, 1b to 1 g described in each of the embodiments. Hereinafter, the power generation elements 1, 1b to 1 g are collectively referred to as a power generation element 1. The anode of the power generation element 1 (for example, the first electrode 11) connects the GND terminal (GND) of the electronic component 501, the negative terminal (-) of the main power supply 502, or the GND terminal (GND) and the negative terminal (-). It is electrically connected to the wiring to be used. The cathode of the power generation element 1 (for example, the second electrode 12) connects the Vcc terminal (Vcc) of the electronic component 501, the positive terminal (+) of the main power supply 502, or the Vcc terminal (Vcc) and the positive terminal (+). It is electrically connected to the wiring to be used. In the electronic device 500, the auxiliary power supply 503 is used in combination with the main power supply 502, for example, as a power source for assisting the main power supply 502 or as a power source for backing up the main power supply 502 when the capacity of the main power supply 502 is exhausted. be able to. When the main power source 502 is a rechargeable battery, the auxiliary power source 503 can also be used as a power source for charging the battery.
　図１５（ｂ）に示すように、主電源５０２は、発電素子１とされてもよい。発電素子１のアノードは、電子部品５０１のＧＮＤ端子（ＧＮＤ）と電気的に接続される。発電素子１のカソードは、電子部品５０１のＶｃｃ端子（Ｖｃｃ）と電気的に接続される。図１５（ｂ）に示す電子機器５００は、主電源５０２として使用される発電素子１と、発電素子１を用いて駆動されることが可能な電子部品５０１と、を備えている。発電素子１は、独立した電源（例えばオフグリッド電源）である。このため、電子機器５００は、例えば自立型（スタンドアローン型）にできる。しかも、発電素子１は、環境発電型（エナジーハーベスト型）である。図１５（ｂ）に示す電子機器５００は、電池の交換が不要である。 As shown in FIG. 15B, the main power source 502 may be the power generation element 1. The anode of the power generation element 1 is electrically connected to the GND terminal (GND) of the electronic component 501. The cathode of the power generation element 1 is electrically connected to the Vcc terminal (Vcc) of the electronic component 501. The electronic device 500 shown in FIG. 15B includes a power generation element 1 used as a main power source 502 and an electronic component 501 that can be driven by the power generation element 1. The power generation element 1 is an independent power source (for example, an off-grid power source). Therefore, the electronic device 500 can be made, for example, a self-supporting type (stand-alone type). Moreover, the power generation element 1 is an energy harvesting type (energy harvesting type). In the electronic device 500 shown in FIG. 15B, it is not necessary to replace the battery.
　図１５（ｃ）に示すように、電子部品５０１が発電素子１を備えていてもよい。発電素子１のアノードは、例えば、回路基板（図示は省略する）のＧＮＤ配線と電気的に接続される。発電素子１のカソードは、例えば、回路基板（図示は省略する）のＶｃｃ配線と電気的に接続される。この場合、発電素子１は、電子部品５０１の、例えば補助電源５０３として使うことができる。 As shown in FIG. 15C, the electronic component 501 may include the power generation element 1. The anode of the power generation element 1 is electrically connected to, for example, the GND wiring of a circuit board (not shown). The cathode of the power generation element 1 is electrically connected to, for example, the Vcc wiring of a circuit board (not shown). In this case, the power generation element 1 can be used as an electronic component 501, for example, an auxiliary power supply 503.
　図１５（ｄ）に示すように、電子部品５０１が発電素子１を備えている場合、発電素子１は、電子部品５０１の、例えば主電源５０２として使うことができる。 As shown in FIG. 15D, when the electronic component 501 includes the power generation element 1, the power generation element 1 can be used as, for example, the main power source 502 of the electronic component 501.
　図１５（ｅ）～図１５（ｈ）のそれぞれに示すように、電子機器５００は、発電装置１００を備えていてもよい。発電装置１００は、電気エネルギーの源として発電素子１を含む。 As shown in each of FIGS. 15 (e) to 15 (h), the electronic device 500 may include a power generation device 100. The power generation device 100 includes a power generation element 1 as a source of electric energy.
　図１５（ｄ）に示した実施形態は、電子部品５０１が主電源５０２として使用される発電素子１を備えている。同様に、図１５（ｈ）に示した実施形態は、電子部品５０１が主電源として使用される発電装置１００を備えている。これらの実施形態では、電子部品５０１が、独立した電源を持つ。このため、電子部品５０１を、例えば自立型とすることができる。自立型の電子部品５０１は、例えば、複数の電子部品を含み、かつ、少なくとも１つの電子部品が別の電子部品と離れているような電子機器に有効に用いることができる。そのような電子機器５００の例は、センサである。センサは、センサ端末（スレーブ）と、センサ端末から離れたコントローラ（マスター）と、を備えている。センサ端末及びコントローラのそれぞれは、電子部品５０１である。センサ端末が、発電素子１又は発電装置１００を備えていれば、自立型のセンサ端末となり、有線での電力供給の必要がない。発電素子１又は発電装置１００は環境発電型であるので、電池の交換も不要である。センサ端末は、電子機器５００の１つと見なすこともできる。電子機器５００と見なされるセンサ端末には、センサのセンサ端末に加えて、例えば、ＩｏＴワイヤレスタグ等が、さらに含まれる。 The embodiment shown in FIG. 15D includes a power generation element 1 in which the electronic component 501 is used as the main power source 502. Similarly, the embodiment shown in FIG. 15H includes a power generation device 100 in which the electronic component 501 is used as the main power source. In these embodiments, the electronic component 501 has an independent power source. Therefore, the electronic component 501 can be made, for example, a self-standing type. The self-supporting electronic component 501 can be effectively used, for example, in an electronic device including a plurality of electronic components and in which at least one electronic component is separated from another electronic component. An example of such an electronic device 500 is a sensor. The sensor includes a sensor terminal (slave) and a controller (master) away from the sensor terminal. Each of the sensor terminal and the controller is an electronic component 501. If the sensor terminal includes the power generation element 1 or the power generation device 100, it becomes a self-supporting sensor terminal, and there is no need to supply electric power by wire. Since the power generation element 1 or the power generation device 100 is an energy harvesting type, it is not necessary to replace the battery. The sensor terminal can also be regarded as one of the electronic devices 500. In addition to the sensor terminal of the sensor, the sensor terminal regarded as the electronic device 500 further includes, for example, an IoT wireless tag and the like.
　図１５（ａ）～図１５（ｈ）のそれぞれに示した実施形態において共通することは、電子機器５００は、熱エネルギーを電気エネルギーに変換する発電素子１と、発電素子１を電源に用いて駆動されることが可能な電子部品５０１と、を含むことである。 What is common to the embodiments shown in FIGS. 15A to 15H is that the electronic device 500 uses a power generation element 1 that converts thermal energy into electrical energy and a power generation element 1 as a power source. It includes an electronic component 501 that can be driven.
　電子機器５００は、独立した電源を備えた自律型（オートノマス型）であってもよい。自律型の電子機器の例は、例えばロボット等を挙げることができる。さらに、発電素子１又は発電装置１００を備えた電子部品５０１は、独立した電源を備えた自律型であってもよい。自律型の電子部品の例は、例えば可動センサ端末等を挙げることができる。 The electronic device 500 may be an autonomous type (autonomous type) having an independent power supply. Examples of autonomous electronic devices include robots and the like. Further, the electronic component 501 including the power generation element 1 or the power generation device 100 may be an autonomous type having an independent power source. Examples of autonomous electronic components include movable sensor terminals and the like.
　以上、この発明の実施形態のいくつかを説明したが、これらの実施形態は例として提示したものであり、発明の範囲を限定することは意図していない。例えば、これらの実施形態は、適宜組み合わせて実施することが可能である。また、この発明は、上記いくつかの実施形態の他、様々な新規な形態で実施することができる。したがって、上記いくつかの実施形態のそれぞれは、この発明の要旨を逸脱しない範囲で、種々の省略、置き換え、変更が可能である。このような新規な形態や変形は、この発明の範囲や要旨に含まれるとともに、特許請求の範囲に記載された発明、及び特許請求の範囲に記載された発明の均等物の範囲に含まれる。 Although some of the embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. For example, these embodiments can be implemented in appropriate combinations. In addition to the above-mentioned several embodiments, the present invention can be implemented in various novel embodiments. Therefore, each of the above-mentioned several embodiments can be omitted, replaced, or changed in various ways without departing from the gist of the present invention. Such novel forms and modifications are included in the scope and gist of the present invention, as well as in the scope of the invention described in the claims and the equivalent of the invention described in the claims.
１　　　：発電素子（第１実施形態）
１ｂ　　：発電素子（第２実施形態）
１ｃ　　：発電素子（第３実施形態）
１ｄ　　：発電素子（第４実施形態）
１ｅ　　：発電素子（第５実施形態）
１ｆ　　：発電素子（第６実施形態）
１ｇ　　：発電素子（第７実施形態）
１１　　：第１電極
　１１ｂ：第１酸化被膜
　１１ｃ：還元層
１２　　：第２電極
　１２ａ：酸化物
　１２ｂ：第２酸化被膜
　１２ｄ：表面改質層
１３　　：中間部
１４　　：ナノ粒子
　１４ａ：絶縁膜
１５　　：溶媒
２１　　：第１基板
２１ａ　：第１フレキシブル基板
２２　　：第２基板
２２ａ　：第２フレキシブル基板
２３　　：支持部
１００　：発電装置
１０１　：第１外部端子
１０２　：第２外部端子
１１１　：第１外部配線
１１２　：第２外部配線
Ｇ　　　：ギャップ
ＧＥ　　：電極間ギャップ
Ｋ　　　：カソード
Ａ　　　：アノード
Ｈ２３　：支持部２３の高さ
Ｒ　　　：負荷
ｅ　　　：電子
φＫ　　：第１電極１１の仕事関数の値
φＡ　　：第２電極１２の仕事関数の値
φＮ　　：ナノ粒子１４の仕事関数の値
ＴＰ１　：第１試験片
ＴＰ２　：第２試験片
ＴＰ３　：第３試験片
ＴＰ４　：第４試験片
ＴＰ５　：第５試験片
ＴＰ６　：第６試験片 1: Power generation element (first embodiment)
1b: Power generation element (second embodiment)
1c: Power generation element (third embodiment)
1d: Power generation element (fourth embodiment)
1e: Power generation element (fifth embodiment)
1f: Power generation element (sixth embodiment)
1g: Power generation element (7th embodiment)
11: First electrode 11b: First oxide film 11c: Reduction layer 12: Second electrode 12a: Oxide 12b: Second oxide film 12d: Surface modification layer 13: Intermediate portion 14: Nanoparticles 14a: Insulation film 15: Solvent 21: First substrate 21a: First flexible substrate 22: Second substrate 22a: Second flexible substrate 23: Support portion 100: Power generation device 101: First external terminal 102: Second external terminal 111: First external wiring 112 : Second external wiring G: Gap GE: Gap between electrodes K: Cathode A: Anode H23: Height of support portion 23 R: Load e: Electron φK: Work function value of first electrode 11 φA: Second electrode 12 Work function value φN: Work function value of nanoparticles 14 TP1: 1st test piece TP2: 2nd test piece TP3: 3rd test piece TP4: 4th test piece TP5: 5th test piece TP6: 6th test One piece

Claims (20)

  1. 　熱エネルギーを電気エネルギーに変換する発電素子の電極の仕事関数の制御方法であって、
    　前記発電素子は、
    　　第１電極と、
    　　第１電極とギャップを介して対向した第２電極と、
    　　前記ギャップ内に設けられた、前記第１電極の仕事関数と前記第２電極の仕事関数との間の仕事関数を有するナノ粒子を含む中間部と、
    　を有し、
    　前記第１電極及び前記第２電極のそれぞれは、同じ導電性物質であり、
    　前記第２電極をアニールし、前記第２電極の仕事関数の値を、前記第１電極の仕事関数の値から、前記ナノ粒子の仕事関数の値を超えて変化させること
    　を特徴とする電極の仕事関数の制御方法。     It is a method of controlling the work function of the electrodes of a power generation element that converts thermal energy into electrical energy.
    The power generation element is
    With the first electrode
    With the second electrode facing the first electrode via a gap,
    An intermediate portion provided in the gap containing nanoparticles having a work function between the work function of the first electrode and the work function of the second electrode.
    Have,
    Each of the first electrode and the second electrode is the same conductive substance, and is
    An electrode characterized by annealing the second electrode and changing the value of the work function of the second electrode from the value of the work function of the first electrode beyond the value of the work function of the nanoparticles. How to control work functions.
  2. 　前記アニールは、酸化性雰囲気中で行い、
    　前記第２電極の少なくとも前記第１電極と対向する面を、酸化すること
    　を特徴とする請求項１記載の電極の仕事関数の制御方法。     The annealing is performed in an oxidizing atmosphere.
    The method for controlling a work function of an electrode according to claim 1, wherein at least a surface of the second electrode facing the first electrode is oxidized.
  3. 　前記第１電極の少なくとも前記第２電極と対向する面上には、前記導電性物質の第１酸化被膜が有り、
    　前記第２電極の少なくとも前記第１電極と対向する面上には、前記導電性物質の第２酸化被膜が有り、
    　前記アニールは、酸化性雰囲気中で行い、
    　前記アニールにより、
    　（１）前記第２酸化被膜の酸化数を、前記第１酸化被膜の酸化数よりも増加させること
    　（２）前記第２酸化被膜の厚さを、前記第１酸化被膜の厚さよりも厚くすること
    　（３）前記第２酸化被膜を、前記第１酸化被膜から同素変態させること
    　前記（１）～（３）の少なくとも１つを行うこと
    　を特徴とする請求項１記載の電極の仕事関数の制御方法。     At least on the surface of the first electrode facing the second electrode, there is a first oxide film of the conductive substance.
    At least on the surface of the second electrode facing the first electrode, there is a second oxide film of the conductive substance.
    The annealing is performed in an oxidizing atmosphere.
    By the annealing
    (1) The oxidation number of the second oxide film is increased from the oxidation number of the first oxide film. (2) The thickness of the second oxide film is made thicker than the thickness of the first oxide film. (3) The work function of the electrode according to claim 1, wherein the second oxide film is passivated from the first oxide film by performing at least one of the above (1) to (3). Control method.
  4. 　前記酸化性雰囲気は、大気であること
    　を特徴とする請求項３記載の電極の仕事関数の制御方法。     The method for controlling the work function of an electrode according to claim 3, wherein the oxidizing atmosphere is an atmosphere.
  5. 　前記アニールは、還元性雰囲気中で行い、
    　前記第２電極の少なくとも前記第１電極と対向する面を、還元すること
    　を特徴とする請求項１記載の電極の仕事関数の制御方法。     The annealing is performed in a reducing atmosphere.
    The method for controlling a work function of an electrode according to claim 1, wherein at least a surface of the second electrode facing the first electrode is reduced.
  6. 　前記第１電極の少なくとも前記第２電極と対向する面上には、前記導電性物質の第１酸化被膜が有り、
    　前記第２電極の少なくとも前記第１電極と対向する面上には、前記導電性物質の第２酸化被膜が有り、
    　前記アニールは、還元性雰囲気中で行い、
    　前記アニールにより、
    　（４）前記第２酸化被膜の酸化数を、前記第１酸化被膜の酸化数よりも減少させる
    　（５）前記第２酸化被膜の厚さを、前記第１酸化被膜の厚さよりも薄くする
    　（６）前記第２酸化被膜を、前記第１酸化被膜から同素変態させる
    　前記（４）～（６）の少なくとも１つを行うこと
    　を特徴とする請求項１記載の電極の仕事関数の制御方法。     At least on the surface of the first electrode facing the second electrode, there is a first oxide film of the conductive substance.
    At least on the surface of the second electrode facing the first electrode, there is a second oxide film of the conductive substance.
    The annealing is performed in a reducing atmosphere.
    By the annealing
    (4) Decrease the oxidation number of the second oxide film from the oxidation number of the first oxide film (5) Make the thickness of the second oxide film thinner than the thickness of the first oxide film (5) 6) The method for controlling the work function of an electrode according to claim 1, wherein at least one of the above (4) to (6) is performed to passivate the second oxide film from the first oxide film. ..
  7. 　前記第１酸化被膜及び前記アニールされる前の第２酸化被膜のそれぞれは、前記導電性物質の自然酸化被膜であること
    　を特徴とする請求項３～６のいずれか１つに記載の電極の仕事関数の制御方法。     The electrode according to any one of claims 3 to 6, wherein each of the first oxide film and the second oxide film before being annealed is a natural oxide film of the conductive substance. How to control work functions.
  8. 　前記アニールは、減圧下又は不活性雰囲気中で行い、
    　前記第２電極を、前記第１電極から同素変態させること
    　を特徴とする請求項１記載の電極の仕事関数の制御方法。     The annealing is performed under reduced pressure or in an inert atmosphere.
    The method for controlling the work function of an electrode according to claim 1, wherein the second electrode is allotropically transformed from the first electrode.
  9. 　前記アニールは、活性雰囲気中で行い、
    　前記第２電極の少なくとも前記第１電極と対向する面を、表面改質すること
    　を特徴とする請求項１記載の電極の仕事関数の制御方法。     The annealing is performed in an active atmosphere.
    The method for controlling a work function of an electrode according to claim 1, wherein at least a surface of the second electrode facing the first electrode is surface-modified.
  10. 　前記導電性物質は、第４族元素を含むこと
    　を特徴とする請求項１～９のいずれか１つに記載の電極の仕事関数の制御方法。     The method for controlling the work function of an electrode according to any one of claims 1 to 9, wherein the conductive substance contains a Group 4 element.
  11. 　前記第１電極はアニールしないこと、前記第１電極のアニール温度は前記第２電極よりも低いこと、前記第１電極のアニール時間は前記第２電極よりも短いこと又は前記第１電極のアニールエネルギーは前記第２電極よりも低いこと
    　を特徴とする請求項１～１０のいずれか１つに記載の電極の仕事関数の制御方法。     The first electrode is not annealed, the annealing temperature of the first electrode is lower than that of the second electrode, the annealing time of the first electrode is shorter than that of the second electrode, or the annealing energy of the first electrode. Is a method for controlling the work function of an electrode according to any one of claims 1 to 10, wherein is lower than the second electrode.
  12. 　前記アニールは、熱アニール、レーザアニール及び光アニールの少なくとも１つを含むこと
    　を特徴とする請求項１～１１のいずれか１つに記載の電極の仕事関数の制御方法。     The method for controlling a work function of an electrode according to any one of claims 1 to 11, wherein the annealing includes at least one of thermal annealing, laser annealing, and optical annealing.
  13. 　第１電極と、
    　第１電極とギャップを介して対向した第２電極と、
    　前記ギャップ内に設けられた、前記第１電極の仕事関数と前記第２電極の仕事関数との間の仕事関数を有するナノ粒子を含む中間部と、
    　を有し、
    　前記第１電極及び前記第２電極のそれぞれは、同じ導電性物質であり、
    　前記第２電極の少なくとも前記第１電極と対向する面の状態は、前記第１電極の少なくとも前記第２電極と対向する面の状態と異なること
    　を特徴とする発電素子。     With the first electrode
    With the second electrode facing the first electrode via a gap,
    An intermediate portion provided in the gap containing nanoparticles having a work function between the work function of the first electrode and the work function of the second electrode.
    Have,
    Each of the first electrode and the second electrode is the same conductive substance, and is
    A power generation element characterized in that the state of at least the surface of the second electrode facing the first electrode is different from the state of the surface of the first electrode facing at least the second electrode.
  14. 　前記第２電極の少なくとも前記第１電極と対向する面は、酸化されていること
    　を特徴とする請求項１３記載の発電素子。     The power generation element according to claim 13, wherein at least a surface of the second electrode facing the first electrode is oxidized.
  15. 　前記第２電極の少なくとも前記第１電極と対向する面は、還元されていること
    　を特徴とする請求項１３記載の発電素子。     The power generation element according to claim 13, wherein at least a surface of the second electrode facing the first electrode is reduced.
  16. 　前記第１電極の少なくとも前記第２電極と対向する面上には、前記導電性物質の第１酸化被膜が有り、
    　前記第２電極の少なくとも前記第１電極と対向する面上には、前記導電性物質の第２酸化被膜が有り、
    　前記第２酸化被膜は、
    　（７）前記第２酸化被膜の酸化数は、前記第１酸化被膜の酸化数よりも大きい
    　（８）前記第２酸化被膜の厚さは、前記第１酸化被膜の厚さよりも厚い
    　（９）前記第２酸化被膜は、前記第１酸化被膜の同素変態物を含む
    　前記（７）～（９）に記載された少なくとも１つの状態を取ること
    　を特徴とする請求項１３記載の発電素子。     At least on the surface of the first electrode facing the second electrode, there is a first oxide film of the conductive substance.
    At least on the surface of the second electrode facing the first electrode, there is a second oxide film of the conductive substance.
    The second oxide film is
    (7) The oxidation number of the second oxide film is larger than the oxidation number of the first oxide film. (8) The thickness of the second oxide film is thicker than the thickness of the first oxide film (9). The power generation element according to claim 13, wherein the second oxide film takes at least one state according to the above (7) to (9), which contains a homogenous transformation of the first oxide film.
  17. 　前記第２電極は、前記第１電極の同素変態物を含むこと
    　を特徴とする請求項１３記載の発電素子。     The power generation element according to claim 13, wherein the second electrode contains an allotropic transformation product of the first electrode.
  18. 　前記第２電極の少なくとも前記第１電極と対向する面は、表面改質されていること
    　を特徴とする請求項１３記載の発電素子。     The power generation element according to claim 13, wherein at least a surface of the second electrode facing the first electrode is surface-modified.
  19. 　前記導電性物質は、第４族元素を含むこと
    　を特徴とする請求項１３～１８のいずれか１つに記載の発電素子。     The power generation element according to any one of claims 13 to 18, wherein the conductive substance contains a Group 4 element.
  20. 　第１基板上に、第１電極を形成する工程と、
    　第２基板上に、前記第１電極と同じ導電性物質である第２電極を形成する工程と、
    　前記第２電極をアニールし、前記第２電極の仕事関数を、前記第１電極の仕事関数から変化させる工程と、
    　前記第１電極と前記第２電極とを、ギャップを介して対向させる工程と、
    　前記第１電極の仕事関数と前記第２電極の前記変化された仕事関数との間の仕事関数を有するナノ粒子を、前記ギャップ内に導入する工程と、
    　を備えたことを特徴とする発電素子の製造方法。     The process of forming the first electrode on the first substrate and
    A step of forming a second electrode, which is the same conductive substance as the first electrode, on the second substrate, and
    A step of annealing the second electrode and changing the work function of the second electrode from the work function of the first electrode.
    A step of making the first electrode and the second electrode face each other through a gap,
    A step of introducing nanoparticles having a work function between the work function of the first electrode and the changed work function of the second electrode into the gap.
    A method of manufacturing a power generation element, which is characterized by being provided with.
PCT/JP2020/037950 2019-11-12 2020-10-07 Method for controlling work function of electrode, power generation element, and method for producing power generation element WO2021095403A1 (en)

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