Heat-shielding device, heat-shielding film, and heat-shielding composition

Abstract

The present disclosure provides a heat shield device 101 provided with a heat shield film 10 including: particles absorbing infrared rays to generate electrons and holes; and an acceptor receiving the electrons or the holes from the particles, wherein charge carriers selected from the electrons and the holes are discharged from the heat shield film 10 to the outside of the device. The heat shield device 101 can function as a "heat removal" device. The heat shield film 10 may be a single layer or may be a multilayer film.

Description

[Technical Field]

[0001] The present invention relates to a heat-shielding device, a heat-shielding film, and a heat-shielding composition that use infrared-absorbing particles. [Background technology]

[0002] It has been proposed to use infrared-absorbing particles (hereinafter sometimes referred to as "infrared-absorbing particles") for heat-shielding purposes. For example, Patent Document 1 discloses a heat-shielding composition containing tin-doped indium tin oxide (ITO) particles and a transparent resin. Patent Document 2 discloses a heat-shielding composition containing infrared-absorbing particles, silica particles, and polymer emulsion particles. Patent Document 2 also discloses antimony-doped tin oxide (ATO), zinc oxide, and the like, in addition to ITO, as materials constituting the infrared-absorbing particles. Heat-shielding compositions containing infrared-absorbing particles are suitable for suppressing the amount of heat that enters while transmitting a portion of the incident light. The heat-shielding composition is applied to a substrate such as a glass plate or a resin film to form a heat-shielding film, which is used together with the substrate as a heat-shielding device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2016 / 185951 [Patent Document 2] Japanese Patent Application Laid-Open No. 2011-181636 Summary of the Invention [Problem to be solved by the invention]

[0004] Improvements to heat-shielding compositions and heat-shielding materials containing infrared-absorbing particles have been carried out mainly with a focus on improving the transmittance in a predetermined wavelength range, particularly the visible range, while suppressing the inflow of infrared rays. Patent Documents 1 and 2 also attempt to improve the compositions from a basically similar perspective, i.e., from the perspective of improving wavelength selectivity.

[0005] An object of the present invention is to improve a heat-shielding device using infrared-absorbing particles from a new perspective. Another object of the present invention is to provide a heat-shielding film and a heat-shielding composition suitable for this heat-shielding device. [Means for solving the problem]

[0006] In conventional heat shielding devices using infrared absorbing particles, part of the energy absorbed by the particles flows into the side where the infrared radiation should be restricted, for example, the indoor side, due to heat transfer such as radiation.

[0007] The present inventors came up with a new idea of ​​suppressing the energy absorbed by the infrared absorbing particles from being released as heat in the direction where the inflow of energy should be restricted, and based on this idea, they conducted extensive research and completed the present invention.

[0008] The present invention provides A heat-shielding device that blocks at least a portion of irradiated infrared rays, a heat-shielding film including particles that absorb the infrared rays to generate electrons and holes, and acceptors that receive the electrons or the holes from the particles; At least a portion of the charge carriers selected from the electrons and the holes is emitted from the heat-shielding film to the outside of the heat-shielding device. A heat shielding device is provided.

[0009] The present invention also provides A heat-shielding film that blocks at least a portion of irradiated infrared rays, particles that absorb the infrared light to generate electrons and holes; and acceptors that can receive the electrons or the holes from the particles; i) a charge generating layer including the particles and a charge receiving layer including the acceptor, the charge generating layer and the charge receiving layer being in contact with each other; or ii) a monolayer film comprising the particles and the acceptor; A heat-shielding film is provided.

[0010] Furthermore, the present invention provides A heat-shielding composition for forming a heat-shielding film, The present invention includes a particle that absorbs infrared light to generate an electron and a hole, and an acceptor that can receive the electron or the hole from the particle, iii) a first composition comprising the particles and a second composition comprising the acceptor; or iv) a composition comprising the particles and the acceptor; A heat-shielding composition is provided. [Effects of the Invention]

[0011] According to the present invention, a new device suitable for suppressing the release of energy absorbed by infrared absorbing particles as heat is provided. In the present invention, at least a portion of charge carriers generated by absorption of infrared rays are transferred to acceptors and then released outside the device, suppressing recombination and, as a result, suppressing the release of thermal energy. According to the present invention, a film and a composition suitable for producing this device are provided. [Brief explanation of the drawings]

[0012] [Figure 1A] 10 is a schematic diagram for explaining a temperature rise of a heat absorber due to infrared rays when no heat-shielding device is used. FIG. [Figure 1B] FIG. 10 is a schematic diagram for explaining the heat shielding mechanism of a conventional device. [Figure 1C] FIG. 10 is a schematic diagram for explaining the heat shielding mechanism of another conventional device. [Figure 1D] FIG. 2 is a schematic diagram for explaining the heat-shielding mechanism of the device of the present invention. [Figure 2A] 1 is a diagram showing a cross section of one embodiment of a device of the present invention together with an outline of a conductive portion. [Figure 2B] FIG. 2B is a diagram illustrating an example of the emission of charge carriers in the device shown in FIG. 2A. [Figure 3] FIG. 10 is a diagram showing a cross section of another embodiment of the device of the present invention together with an outline of the conductive portion. [Figure 4] FIG. 10 is a diagram showing a cross section of yet another embodiment of the device of the present invention together with an outline of the conductive portion. [Figure 5] FIG. 2 is a diagram showing a cross section of a photoelectric conversion device together with a circuit connected to the device. [Figure 6] FIG. 10 is a diagram showing a cross section of yet another embodiment of the device of the present invention together with an outline of the conductive portion. [Figure 7] FIG. 10 is a diagram showing a cross section of yet another embodiment of the device of the present invention together with an outline of the conductive portion. [Figure 8] 10 is an example of the results of measuring the relaxation time from localized surface plasmon excitation. [Figure 9] The left image shows a composite particle in which an infrared-absorbing particle and an acceptor are bonded, and the right image explains the separation of charges that occurs in the composite particle in response to infrared irradiation. [Figure 10] 1A and 1B are diagrams illustrating application examples of the device of the present invention. [Figure 11] FIG. 10 shows another application example of the device of the present invention. [Figure 12] FIG. 10 shows another application example of the device of the present invention. [Figure 13] FIG. 1 is a diagram showing an example of temperature change in a device of the present invention. [Figure 14] FIG. 10 is a diagram showing an example of change in the intensity of the absorption spectrum as the fading reaction of methylene blue due to charge carriers supplied from the heat-shielding film progresses. [Figure 15] FIG. 1 shows the results of measuring the change over time in the absorption peak intensity of methylene blue using a heat-shielding film that is a laminated film (CuS / CdS) and a heat-shielding film that is a single-layer mixed film (CuS-CdS mixed film). DETAILED DESCRIPTION OF THE INVENTION

[0013] In this specification, "infrared radiation" refers to electromagnetic waves with wavelengths of 0.7 to 1000 μm. The term "semiconductor" is used to encompass not only conventional semiconductors but also semimetals and degenerate semiconductors. Semimetals are materials with a band structure in which the lower part of the conduction band and the upper part of the valence band slightly overlap across the Fermi level due to distortion of the crystal structure or interactions between crystal layers. A "degenerate semiconductor" is a semiconductor material whose Fermi level is located in the conduction band or valence band when doped. A "nanoparticle" refers to a particle with a minimum diameter of less than 1 μm, for example, in the range of 0.1 nm to 1 μm. A nanoparticle typically refers to a particle with a maximum dimension of 5 μm or less, preferably in the range of 3 nm to 2 μm. The "minimum diameter" is determined by the smallest dimension passing through the center of gravity of the particle, and the "maximum dimension" is determined by the longest line segment that can be drawn within the particle. The term "functional group" is used to include halogen atoms. A "charge carrier" refers to an electron and / or a hole. The "principal surface" of a film is the film surface that extends in a direction perpendicular to the thickness direction of the film.

[0014] In a photoelectric conversion device, at least a portion of the charge carriers generated in the photoelectric conversion unit are supplied to a conductive unit that, together with the device, constitutes a circuit including at least one of an inverter, a power storage device, a voltmeter, and an ammeter. In contrast, in the present invention, the outside to which at least a portion of the charge carriers generated in the film are released does not have to correspond to the conductive unit that, together with the heat-shielding device, constitutes the above-mentioned circuit. The outside to which the charge carriers are released may be other than the circuit including at least one of an inverter, a power storage device, a voltmeter, and an ammeter. In one embodiment of the present invention, the heat-shielding device is connected to a conductive unit other than the circuit including at least one of an inverter, a power storage device, a voltmeter, and an ammeter, and releases at least a portion of the charge carriers to this conductive unit.

[0015] The outside from which the charge carriers are released is not limited to a solid. The outside may contain a gas or a liquid. The heat-shielding film may have a main surface exposed to the gas or liquid. In contrast, both main surfaces of the photoelectric conversion film that performs the power generation function in the photoelectric conversion device are in contact with a layer that transports charge carriers.

[0016] One way in which charge carriers are released to the outside of the device is, but is not limited to, conduction to the outside. At least a portion of the charge carriers can be released by oxidizing or reducing chemical species outside the device at the surface of the device. In other words, the process of releasing charge carriers may be a process in which the amount of charge carriers decreases as chemical species outside the device are oxidized or reduced. This reaction typically occurs at the interface between the thermal shielding device and the outside, for example, at the main surface, which is the exposed surface of the thermal shielding film.

[0017] Charge carriers can be released by conduction alone, by oxidation or reduction alone, or by a combination of reaction and conduction. In one embodiment of the present invention, the exterior from which charge carriers are released includes a first exterior that is a gas or liquid and a second exterior that is a solid, and at least a portion of either electrons or holes is released by oxidizing or reducing chemical species in the first exterior, and at least a portion of the other selected from electrons and holes is released by conduction to the second exterior.

[0018] The external part may be a solid conductive part that may have a ground (GND) potential. The ground potential may be earth potential. The external part may be a circuit that converts the energy of emitted charge carriers into Joule heat only. The circuit does not need to include active elements such as transistors. The circuit may have only resistors as passive elements. The resistor may be a resistive element designed to have a predetermined resistance value, or may be any other resistive element. The resistor may be a component designed for a purpose other than providing electrical resistance. An example of this type of component is a component designed to support a device. The circuit may have only resistive elements as elements, excluding switch elements.

[0019] At least a part of the charge carriers emitted from the film are emitted to the outside, which has, for example, a ground potential, in particular an earth potential, and the energy they have is converted, for example, only into Joule heat in the resistor.

[0020] The heat-shielding device may further include a conductive part for discharging charge carriers to the outside. The conductive part inside the device may include, for example, at least one selected from a conductive wire and a connection terminal for connecting to an external conductive part. The conductive part included in the heat-shielding device may be electrically connected to an external circuit other than at least one of an inverter, a power storage device, a voltmeter, and an ammeter.

[0021] The conductive portion may have a switch element. The switch element may be a manual element or an element configured to be controllable by an external input signal. The switch element may be an element that controls the electrical connection between the heat-shielding device and the outside of the device. The switch element may, for example, start, stop, or adjust the amount of charge carrier emission from the heat-shielding device by controlling the conduction of charge carriers. Adjusting the amount of charge carriers emitted from the heat-shielding device may also control the recombination of charge carriers, thereby controlling the infrared rays re-emitted from the heat-shielding device.

[0022] The heat-shielding device may include an electrode connected to a conductive part or for connection to an external conductive part. The electrode may be a light-transmitting electrode called a transparent electrode, or a light-non-transmitting electrode such as a metal electrode.

[0023] The heat-shielding device may further include a non-transparent electrode. The area where the non-transparent electrode is formed may be less than 50% of the light-receiving area where infrared light is incident on the device. This ratio may be 1% or more but less than 50%, or even 5% or more but less than 50%.

[0024] In the heat-shielding device, the conductive portion may include an electrode that receives charge carriers from the heat-shielding film. The conductive portion may also include first and second electrodes arranged to sandwich the heat-shielding film. The first and second electrodes may be a combination of a light-transmitting electrode and a non-light-transmitting electrode, a combination of light-transmitting electrodes, or a combination of non-light-transmitting electrodes. However, the conductive portion may include only the first electrode or the second electrode, i.e., a single electrode or multiple electrodes formed to contact only one of the film surfaces of the shielding film.

[0025] The heat-shielding device may further include a resistive element. In the resistive element, at least a portion of the energy of the charge carriers emitted from the film is converted into Joule heat. For example, the conductive portion of the heat-shielding device may include a resistive element designed to have a predetermined resistance value. In this case, the charge carriers can be emitted to the outside of the device via the resistive element in the device.

[0026] In the heat-shielding device, the light transmittance of the heat-shielding film at a wavelength of 700 nm may be 24% or more, 25% or more, or even 30% or more, or in some cases 40% or more. The light transmittance of the heat-shielding film at a wavelength of 600 nm may be 18% or more, 20% or more, or even 30% or more, or in some cases 40% or more.

[0027] The heat-shielding device may have a light-transmitting region that is 50% or more of the light-receiving region where infrared rays are incident. At least a portion of visible light is transmitted through the light-transmitting region. The proportion of the light-transmitting region may be 50% or more, further 70% or more, and particularly 95% or more. The light-transmitting region may be a region that transmits at least a portion of visible light that is incident together with infrared rays. A heat-shielding film may be disposed in the light-transmitting region. Metal members such as connection terminals, non-light-transmitting electrodes, etc. may be disposed in the non-light-transmitting region other than the light-transmitting region.

[0028] In the heat-shielding device, the heat-shielding film may include a charge-generating layer containing particles that absorb infrared light to generate electrons and holes, and a charge-receiving layer containing an acceptor, and the charge-generating layer and the charge-receiving layer may be in contact with each other. In the heat-shielding device according to the present invention, the heat-shielding film may be a single-layer film containing the particles and the acceptor. The heat-shielding film may be formed on the substrate directly or via another film. One example of the other film is an electrode, particularly a transparent electrode.

[0029] The heat-shielding device may further include an adhesive layer for fixing the heat-shielding device.The heat-shielding device may further include a first light-transmissive substrate and a second light-transmissive substrate spaced apart from each other, and a heat-shielding film may be disposed on a surface of the first light-transmissive substrate facing the second light-transmissive substrate and / or a surface of the second light-transmissive substrate facing the first light-transmissive substrate.

[0030] The particles that absorb infrared radiation to generate electrons and holes may include a material that can absorb infrared radiation through localized surface plasmon resonance. The particles may be inorganic particles.

[0031] Hereinafter, the present invention will be further described with reference to the drawings as appropriate, but the following description is not intended to limit the present invention to a specific embodiment. The same members and components in each drawing are designated by the same reference numerals, and duplicated descriptions will be omitted. Matters described with reference to one drawing can also be applied to embodiments shown in other drawings unless an obvious contradiction occurs.

[0032] [Heat shielding by devices] As shown in FIG. 1A, infrared rays 400 emitted from a heat source 200 reach a heat absorber 300, causing a temperature rise ΔT O In FIG. 1B, a heat-shielding device 500 having infrared absorbing properties is disposed between the heat source 200 and the heat absorber 300. The heat-shielding device 500 transmits a portion of the infrared rays 400 and absorbs a portion of the infrared rays. The heat-shielding device 500 reduces the temperature rise ΔT of the heat absorber 300. A can be suppressed to some extent (ΔT A <ΔT O1B. However, the infrared rays 400 absorbed by the heat-shielding device 500 are re-radiated as infrared rays 410 by radiation or the like from the heat-shielding device 500, and a part of these rays reaches the heat absorber 300. Note that the infrared rays are also re-radiated from the heat-shielding device 500 in a direction toward the heat source 200, but the infrared rays toward the heat source 200 are not shown in FIG. 1B. This also applies to FIGS. 1C and 1D.

[0033] 1C, a heat shielding device 600 is provided in place of the thermal device 500, which has enhanced infrared reflectance characteristics of the device 500. In this case, the temperature rise ΔT R It is possible to further suppress (ΔT R <ΔT A ). However, the infrared rays 420 reflected by the heat-shielding device 600 may hinder the temperature reduction in the heat source 200 or in a highly enclosed space containing the heat source 200. The heat source 200, which may be placed in a highly enclosed space, is an artificial heat source, typically an industrial furnace. Even in a space with a low degree of enclosure, the strong reflected infrared rays 420 may have an undesirable effect on the surrounding environment. An example of such infrared rays 420 is the reflected sunlight that is reflected by the exterior wall of a building and reaches an adjacent building.

[0034] The heat shielding device 100 according to this embodiment shown in FIG. 1D discharges part of the energy of the absorbed infrared rays to the outside as charge carriers. Therefore, the temperature rise of the heat absorber 300 due to the re-radiated infrared rays 410 is suppressed (ΔT I <ΔT A ) By using the heat-shielding device 100, the re-radiation of infrared rays is suppressed without relying on an increase in the amount of infrared rays reflected from the device 100. At least a portion of the charge carriers generated by absorbing part of the energy of the infrared rays 400 are released, for example, by conduction to an external conductive part. Unlike release of energy as charge carriers due to reflected light, the release destination can be easily controlled. As described above, the charge carriers can also be released by, for example, being involved in a chemical reaction on the surface of the heat-shielding device 100.

[0035] [Device configuration] In the embodiment shown in FIG. 2A , a heat-shielding device 101 includes a substrate 5 and a heat-shielding film 10 formed on the substrate 5. One of the main surfaces of the heat-shielding film 10 is exposed and in contact with external gas. The heat-shielding film 10 includes infrared-absorbing particles that absorb incident infrared rays and generate electrons and holes, and acceptors that can accept charge carriers, such as electrons or holes, from the infrared-absorbing particles. The heat-shielding device 101 also includes an electrode 8 arranged to be in contact with a portion of the heat-shielding film 10. The electrode 8 is formed on the peripheral portion of the surface of the heat-shielding film 10. The electrode 8 is, for example, a metal film that is substantially opaque, but may also be a light-transmitting film. One end of a conductive portion 11 is connected to the electrode 8. The other end of the conductive portion 11 is connected to a destination 19 for discharging charge carriers. The destination 19 is a charge-receiving portion located outside the device. The conductive portion 11 has a switch element 12 between the electrode 8 and the destination 19.

[0036] Referring to FIG. 2B, an example of the emission of charge carriers in the embodiment of FIG. 2A will be described. In this example, electrons generated in the heat-shielding film 10 reduce external chemical species 70 on the main surface of the heat-shielding film 10, and as a result, are emitted from the heat-shielding device 101. In this example, the heat-shielding film 10 functions as a photocatalyst, promoting the reaction of the chemical species 70. Meanwhile, holes pass through the electrode 8 and the conductive portion 11 and are guided to the emission destination 19. However, the emission of charge carriers shown in FIG. 2B is merely one example of various emission modes. The emission of charge carriers may proceed by a chemical reaction involving oxidation-reduction of external chemical species by the charge carriers, the extraction of charge carriers to the outside, or a combination thereof. The reaction, such as oxidation of the external chemical species, may involve decomposition or modification of the chemical species.

[0037] The discharge destination 19 may be ground, particularly earth, but may also be anything other than earth as long as it can provide the predetermined potential. The predetermined potential may be ground potential or earth potential. The discharge destination 19 may be, for example, a window frame or the body of a car. These can sufficiently function as ground even if they are not grounded. Depending on whether the switch element 12 is opened or closed, the electrode 8 is connected or disconnected from the discharge destination 19, which is, for example, ground. The switch element 12 may be a manual element, or an element whose opening and closing is controlled by a switching control unit (controller) not shown. Note that the switch element 12 is not essential. If the switch element 12 is not present, the electrode 8 is directly connected to the discharge destination 19 via the conductive part 11, and its potential is fixed, for example, to earth potential.

[0038] The conductive portion 11 may be, for example, a conductive wire, but is not limited thereto. It may also be a conductive adhesive, solder, a conductive member, or a combination of these. The conductive adhesive and solder are used, for example, to secure the conductive wire to an electrode. The conductive member may be, for example, a connection terminal that connects the conductive wire to the electrode, or a member for securing the entire device. The connection terminal that joins the conductive wire to the electrode may be, for example, a known terminal for supplying power to an antenna wire on a vehicle glass. Such connection terminals are disclosed in, for example, Japanese Patent Application Laid-Open No. 2001-313513 and Japanese Patent Application Laid-Open No. 2000-151247. The connection terminal allows, for example, an external conductive wire to be electrically connected to the heat shielding device 101 simply by physically inserting it. An example of a member for securing the entire device is a member that supports the periphery of the device so that the device can be installed in a window frame.

[0039] The conductive portion 11 may be provided in advance in the heat-shielding device 101, or may be provided outside the heat-shielding device 101. The conductive portion provided in advance in the heat-shielding device 101 may be connected to an external conductive portion to form the entire conductive portion 11.

[0040] The heat-shielding device 101 has a light-receiving region capable of receiving incident light 50 including infrared rays. The light source of the incident light 50 may be the sun or an artificial light source. Artificial light sources include high-temperature heat sources, such as high-temperature furnaces. The light-receiving region includes a light-transmitting region 41 through which at least a portion of the visible light contained in the incident light 50 passes, and a light-non-transmitting region 42 through which the visible light contained in the incident light 50 is substantially not transmitted. In the light-non-transmitting region 42 of the heat-shielding device 101, an electrode 8 made of metal blocks the transmission of the incident light 50. The proportion of the light-transmitting region 41 in the entire light-receiving region may be 50% or more, 70% or more, or even 90% or more. The visible light transmittance of the light-transmitting region 41 is, for example, 20% or more, or even 30% or more.

[0041] In the heat-shielding device 101, the substrate 5 is light-transmitting, and therefore the light-transmitting region 41 is present. If the substrate 5 were non-light-transmitting, the entire light-receiving region would be a non-light-transmitting region 42. In this case, the device 101 is arranged so that the heat-shielding film 10 is located closer to the incident light side than the substrate 5. However, even in this case, it is desirable that the non-light-transmitting electrode 8 arranged on the light-incident side is formed only in a limited range of the light-receiving region, specifically, in an area less than 50%, less than 30%, or even less than 10% of the light-receiving region. The area where the non-light-transmitting electrode 8 is formed may be 1% or more, 3% or more, or even 5% or more of the light-receiving region.

[0042] As shown in FIGS. 3 and 4 , the heat-shielding devices 102 and 103 may include a transparent electrode 3 instead of or in addition to the electrode 8. In the heat-shielding device 102 shown in FIG. 3 , the transparent electrode 3 is formed between the heat-shielding film 10 and a light-transmitting substrate 5. A part of the surface of the transparent electrode 3 is an exposed region 31 that is not covered by the heat-shielding film 10. The exposed region 31 is used as a connection region with the conductive portion 11. The connection between the transparent electrode 3 and the conductive portion 11 may be performed in the same manner as the connection between the electrode 8 and the conductive portion 11.

[0043] The heat-shielding devices 101 and 102 are connected to a discharge destination 19 via a switch element 12. In contrast, the heat-shielding device 103 constitutes part of a circuit 20 having a resistor 13. From another perspective, a conductive part constituting part of the circuit 20 is present outside the heat-shielding device 103. The resistor 13 may be a passive element designed to exhibit a predetermined resistance value, or it may be a resistive element that is not designed as a passive element. When the resistor 13 is present outside the device, the two conductive parts 11 of the heat-shielding device 103 are connected to the ends of the resistor 13, respectively, to form the circuit 20.

[0044] As shown in the figure, neither an inverter nor a power storage device may be connected to circuit 20. A measuring device functioning as an ammeter and / or a voltmeter may not be connected to circuit 20. Circuit 20 may also not include a power source. The same applies to conductive portion 11. In other words, the charge carriers are released to destination 19 or converted into thermal energy in resistor 13 without passing through any of an inverter, a power storage device, an ammeter, and a voltmeter.

[0045] In the heat shielding devices 101, 102, and 103, the heat shielding film 101 has a main surface exposed to the outside. 50% or more, or even 70% or more of the area of ​​the exposed main surface may be exposed to the outside. The outside that the exposed main surface contacts may be in a gas phase or a liquid phase.

[0046] In the heat shielding devices 101 and 102, charge carriers generated in the heat shielding film 10 are released to the outside through chemical reactions, or can be released to an external release destination 19 via the electrode 3 or 8 and the conductive portion 11. This release significantly reduces the amount of electrons and holes that recombine within the device. Suppressing recombination reduces the amount of heat re-radiated from the device, in other words, suppresses the rise in temperature of the device itself. In the heat shielding device 103, charges generated in the heat shielding film 10 recombine at a resistor 13 outside the device, generating Joule heat. However, even in this case, the amount of electrons and holes that recombine within the device is significantly reduced, and the amount of heat released from the device 103 itself is suppressed.

[0047] Therefore, compared to conventional heat-shielding films that directly absorb infrared rays, the heat-shielding devices 101, 102, and 103 suppress heat re-radiated as infrared rays. For example, by using the heat-shielding devices as building materials, heating of buildings, roads, etc. can be suppressed, contributing to the reduction of the so-called heat island effect. The heat-shielding devices can also be used to suppress heating of electronic devices that emit infrared rays, such as LED displays, and light sources that emit infrared rays, such as headlights. It is also possible to suppress a decrease in the luminous efficiency of these light emitters. The heat-shielding devices may further include a light source that emits light including the infrared range.

[0048] 2A to 4 are simplified for the purpose of explaining the manner of charge release, the heat shielding devices 101 to 103 may further include components not shown. For example, the heat shielding devices 101 and 102 may include two or more electrodes 8 spaced apart from each other and arranged on the heat shielding film 10, and may be connected to two or more discharge destinations 19 via two or more conductive parts 11. The same applies to the heat shielding device 103.

[0049] A typical photovoltaic conversion device will now be described with reference to FIG. 5. A circuit 120 connected to a photovoltaic conversion device 110 includes a charge / discharge controller 115, an inverter 118, and a load 113, all interconnected via conductive wires 111. The controller 115 is further connected to a storage battery 116. In the circuit 120, the wiring between the devices 113, 115, 116, and 118 is shown as a single line for simplification. If the load 113 is a DC load, the inverter 118 is not required, but the storage battery 116 is still required. If the circuit 120 is connected to a power grid of a power company, the storage battery 116 can be omitted, but a power conditioner with inverter functionality is required between the photovoltaic conversion device 110 and the power grid. Unlike the circuit 20 illustrated above, the circuit 120 includes at least one of an inverter and a storage device. Even in a laboratory, a measuring instrument such as a voltmeter is connected to the photovoltaic conversion device to determine its characteristics. Unlike the heat shielding devices exemplified above, the photovoltaic conversion device is connected to at least one of an inverter, a power storage device, a voltmeter, and an ammeter.

[0050] The photovoltaic device 110 includes a transparent electrode 153, an electron transport layer 157, a power generation layer 151, a hole transport layer 159, and a back electrode 158, arranged in this order on a light-transmitting substrate 155. The back electrode 158 extracts current and also functions as a reflective layer for confining a portion of incident light 150 within the device. Therefore, unlike the heat-shielding devices 101 to 103, the photovoltaic device 110 typically includes two electrodes 155 and 158 over substantially the entire device, with no light-transmitting region, or only a very limited region, for improved photovoltaic conversion efficiency. Furthermore, unlike the heat-shielding devices that may include only a single electrode 3 or 8 (see FIGS. 2A and 3), the photovoltaic device 110 requires electrodes 153 and 158, which are separated into multiple layers and sandwich the power generation layer 151.

[0051] In the photovoltaic device 110, the two main surfaces of the power generation layer 151 are entirely covered by adjacent layers 157 and 159 and are not exposed to the outside.

[0052] As described above, it can be understood that the heat-shielding devices 101 to 103 have a heat-shielding film 10 which is an infrared absorbing film, and may be connected to the outside of the device so that at least one selected from the group consisting of v) and vi) below is satisfied. From these embodiments, a method for using an infrared absorbing device as a heat shielding device, the method comprising: providing an infrared absorbing film including particles that absorb infrared light to generate electrons and holes, and acceptors that accept the electrons or holes from the particles; It is possible to grasp a method of using the infrared absorbing device as a heat shielding device, in which the infrared absorbing device is arranged so that at least one selected from the following v) to vii) is established. v) At least a part of the charge carriers selected from the electrons and the holes generated in the infrared absorbing film by irradiation with infrared rays is released by oxidizing or reducing a chemical species that is in contact with a main surface of the infrared absorbing film and is in a gas phase or a liquid phase outside the infrared absorbing device. vi) At least a portion of the electrons and holes generated in the infrared absorbing film by irradiation with infrared rays recombine outside the infrared device, other than a circuit including at least one of an inverter, a power storage device, a voltmeter, and an ammeter. vii) At least a portion of the charge carriers selected from the electrons and holes generated in the infrared absorbing film by irradiation with infrared rays is emitted to the outside of the infrared device having a ground potential.

[0053] However, as described above, the device itself may include a resistive element. In this case, in vi), electrons and holes recombine not only outside the device but also inside the device, generating Joule heat. In vi), the device does not include an inverter, a power storage device, a voltmeter, or an ammeter outside the device.

[0054] Returning to Figures 2A, 2B, 3, and 4, the relationship between the opening and closing of the switch element 12 and re-radiation will be described. Closing the switch element 12 significantly reduces the number of electrons and holes recombining within the devices 101-103, thereby suppressing the amount of heat re-radiated from the devices 101-103. Opening the switch element 12 reduces the amount of charge released to the outside, which increases the temperature of the heat-shielding film 10 and the amount of heat released from the heat-shielding film 10. When the heat-shielding device is used as a window, there may be situations in summer where the amount of heat entering from outside needs to be suppressed. In such situations, closing the switch element 102 is appropriate. On the other hand, in winter, it may be desirable to prevent heat from escaping from inside the room to outside. In such situations, it is appropriate to keep the switch element 102 open. The switch element 102 may be operated manually, or its opening and closing may be automatically controlled by a controller. For example, the controller may receive inputs such as temperatures detected by indoor and outdoor temperature sensors and light intensity detected by an outdoor light sensor.

[0055] The heat-shielding film 10 may be a single-layer film or a multilayer film composed of multiple layers. FIGS. 6 and 7 show examples of heat-shielding devices equipped with a multilayer heat-shielding film. In heat-shielding devices 105 and 106, the heat-shielding film 10 has a charge generation layer 1 and a charge receiving layer 2. The charge generation layer 1 contains particles that absorb infrared light and generate electrons and holes. The charge receiving layer 2 contains acceptors that can receive electrons or holes from the particles. The positions of the charge generation layer 1 and the charge receiving layer 2 may be reversed from those shown in the figure. Note that FIG. 6 shows an example in which the discharge destination 19 is ground.

[0056] As shown in Figures 6 and 7, the heat-shielding device may include only a single charge-receiving layer, or may include two or more charge-receiving layers. In the latter case, a charge-receiving layer that receives electrons may be disposed on one side of a charge-generating layer, and a charge-receiving layer that receives holes may be disposed on the other side. However, a heat-shielding device may function sufficiently even if it includes only a single charge-receiving layer that receives electrons or holes. Furthermore, although not shown, the heat-shielding device may have the configuration shown in Figure 2A in which the conductive portion 11 is connected directly to the heat-shielding film 10 without including the electrode 8. Furthermore, the heat-shielding device may include an electron-transport layer or a hole-transport layer between the heat-shielding film and the electrode. The electron- or hole-transport layer may be disposed, for example, between the charge-receiving layer and an electrode such as a transparent electrode or a metal electrode.

[0057] [Heat-shielding film] The materials and layers that can form the heat shielding film will be described below. (infrared absorbing particles) The infrared absorbing particles are not particularly limited as long as they absorb infrared rays and generate electrons and holes. The infrared absorbing particles can generate carriers with higher energy than the Fermi level carriers as the base. The infrared absorbing particles can contain the following infrared absorbing materials.

[0058] The infrared absorbing material may contain at least one selected from the group consisting of oxides, phosphides, sulfides, selenides, and tellurides, or may contain at least one selected from the group consisting of sulfides, selenides, and tellurides. However, for applications requiring durability such as heat resistance, materials containing oxides are generally suitable. The infrared absorbing material may be a semiconductor or may be doped. Examples of doping include doping with a different element, self-doping, and defect doping.

[0059] The infrared absorption material is preferably an inorganic material as described above. Such infrared absorption particles are suitable for use in applications where a large amount of infrared rays are absorbed and the heat insulating film reaches a high temperature. The infrared absorption particles are not particularly limited as long as they are particles that absorb infrared rays and generate electrons and holes, and are not limited to inorganic particles.

[0060] The infrared absorption material may contain a transparent conductive oxide. Examples of the transparent conductive oxide include tin-doped indium oxide (ITO), aluminum-doped indium oxide, cerium-doped indium oxide, aluminum-doped zinc oxide, gallium-doped zinc oxide, indium-doped zinc oxide, indium-doped cadmium oxide, fluorine indium-doped cadmium oxide, fluorine-doped cadmium oxide, chlorine-doped cadmium oxide, bromine-doped cadmium oxide, cesium-doped molybdenum oxide, antimony-doped tin oxide (ATO), fluorine-doped tin oxide (FTO), titanium oxide, gallium oxide, and vanadium oxide.

[0061] The infrared absorption material may contain at least one selected from the group consisting of copper sulfide, copper phosphide, copper telluride, copper selenide, ruthenium oxide, rhenium oxide, molybdenum oxide, tungsten oxide, tungsten bronzes, and delafossite-type copper oxides, and may contain copper sulfide and / or tungsten oxide.

[0062] Examples of copper sulfide include those represented by CuS or Cu 2-x S(0 < x < 1), examples of copper phosphide include those represented by Cu 3-x P(0 < x < 1) or CuP, examples of copper telluride include those represented by CuTe or Cu 2-x Te(0 < x < 1), examples of copper selenide include those represented by CuSe or Cu 2-x Se(0 < x < 1), respectively.

[0063] Examples of ruthenium oxide include RuO2 or RuO 2-xThose represented by (0 < x < 1) are, as rhenium oxides, ReO2 or ReO 2-x Those represented by (0 < x < 1) are, as molybdenum oxides, MoO3 or MoO 3-x Those represented by (0 < x < 1) are, as tungsten oxides, WO3 or WO 3-x Those represented by (0 < x < 1) can be exemplified respectively.

[0064] Tungsten bronzes are non-stoichiometric compounds in which alkali metals and other metal atoms penetrate into tungsten oxides in a non-stoichiometric ratio. Specifically, CsxWO3 (0 < x < 1; CWO), LiWO3, LiCsWO3, LiRbWO3, and LiKWO3 can be exemplified. As delafossite-type copper oxides, CuAlO2, CuGaO2, and CuCrO2 can be exemplified.

[0065] The infrared absorption particles may contain a material that can absorb infrared rays by local surface plasmon resonance (hereinafter sometimes referred to as "LSPR-IR absorption material"). The presence of LSPR in the LSPR-IR absorption material can be confirmed by, for example, a method that clarifies that there is linearity in the wavelength change of the absorption peak when the refractive index of the surrounding medium is changed. The LSPR-IR absorption material may be a semiconductor. However, the LSPR-IR material is not essential in the infrared absorption particles.

[0066] The LSPR-IR absorption material may be a material in which the relaxation time from local surface plasmon excitation can be 1 ns or more. The material having this property is, for example, at least one selected from the group consisting of copper sulfide, copper selenide, and cesium tungsten oxide (CWO). However, it is not limited to these materials, and the relaxation time from local surface plasmon excitation can be measured by the time-resolved transient absorption spectrum method, and appropriate materials can be selected.

[0067] Figure 8 shows an example of the results of measuring the relaxation time from localized surface plasmon excitation using time-resolved transient absorption spectroscopy. Figure 8 shows absorption spectra 2.5 nanoseconds (ns), 6 ns, and 12.5 ns after localized surface plasmon excitation. The absorption spectrum shown in Figure 8 confirms bleach (negative signal) due to localized surface plasmon excitation in the near-infrared region. In the example shown in Figure 8, the negative signal does not disappear even after 2.5 ns, 6 ns, or even 12.5 ns, indicating a relaxation time of at least 10 ns. Regardless of the wavelength and intensity of the pump light, materials that can exhibit such a long relaxation time of active carriers after LSPR excitation are suitable as LSPR-IR absorbing materials. Time-resolved transient absorption spectroscopy can be performed by directly measuring the entire time period of the phenomenon.

[0068] Figure 8 shows the measurement results for copper sulfide. This measurement was performed using the pump-probe method, which uses a chloroform solution of copper sulfide as the sample, a picosecond laser with a wavelength of 1064 nm as the pump light, and a supercontinuum light source as the probe light. Details of the laser light and probe light are as follows: Picosecond laser (EKSPLA PL2210A, repetition rate 1 kHz, pulse width 25 ps, pulse energy 0.9 mJ (wavelength 1064 nm)) Supercontinuum light source (Fianium "SC450", repetition rate 20MHz, pulse width 50-100ps) However, these conditions are merely an example, and appropriate conditions can be set depending on the material being measured for measuring the relaxation time from localized surface plasmon excitation.

[0069] (Acceptor) The type of acceptor is not particularly limited as long as it can accept electrons or holes from the infrared-absorbing particles. The acceptor material contained in the acceptor is appropriately selected depending on the infrared-absorbing material contained in the infrared-absorbing particles. When the infrared-absorbing material is copper sulfide, the acceptor may contain cadmium sulfide. When the infrared-absorbing material is cesium-doped tungsten oxide, the acceptor may contain, for example, at least one selected from zinc oxide, titanium oxide, tin oxide, and gallium oxide. When the infrared material is ITO, the acceptor may contain tin oxide. The acceptor may be contained as particles or in a layer-forming form. The acceptor may be contained in the same layer as the infrared-absorbing particles or in an adjacent layer. The acceptor may also be a conductive organic material, such as graphene, carbon nanotubes, graphite, or diamond-like carbon.

[0070] (composite particles) The infrared-absorbing particles and the acceptor may be combined together to form a composite particle. An example of a composite particle is shown in Figure 9. This composite particle is composed of ITO particles with tin oxide (SnO2) particles attached to the periphery. The two particles may be physically or chemically combined. As shown in the right diagram of Figure 9, holes and electrons generated by infrared radiation (labeled "radiant heat" in the figure) are separated from the holes remaining in the ITO particles as the electrons move to the acceptor SnO2 particles. Charge separation using composite particles is advantageous for suppressing recombination and efficiently releasing charge carriers.

[0071] (binder) The barrier film may include a binder, which may impart desirable properties such as flexibility, or may be interposed between particles, such as infrared absorbing particles, to impart desirable properties to the film or layer.

[0072] The binder may contain at least one functional group capable of bonding to the particles, such as fluorine (F), chlorine (Cl), bromine (Br), iodine (I), cyanide (CN), thiocyanato (SCN), isothiocyanato (NCS), hydroxide (OH), mercapto (SH), carbonyl (CO), amino (NR), nitrosyl (NO), nitrite (NO), phosphane (PR), carbene (RC), and pyridine (NCH). The functional group may be present as an anion, i.e., for example, F - or the like. Here, each R is independently any organic group or a hydrogen atom. As can be understood from the above examples, the functional group that can be bound to the particle may be any other functional group that can function as a ligand to a metal atom or an anion.

[0073] The binder may be an inorganic or organic compound. The binder may be an ion containing or consisting of the functional group exemplified above, or a salt composed of the ion and its counterion. The binder may also be a compound having multiple of the above functional groups, such as hydrazine (H2NNH2), ethylenediamine (H2NCH2CH2NH2), 1,2-ethanedithiol (HSCH2CH2SH, EDT), mercaptopropionic acid (HSCH2CH2COOH), acetylacetonate (HCCOCHCOCH3), or aminobenzonitrile (NH2C6H4CN).

[0074] It is desirable that the binder contains a compound having a molecular weight of, for example, 280 or less, further 250 or less, preferably 200 or less, more preferably 100 or less, even more preferably 80 or less, and in some cases less than 65. The lower limit of the molecular weight is not particularly limited, but is, for example, 20 or more, further 30 or more. The use of a binder with a molecular weight that is not too large is suitable for narrowly controlling the spacing between nanoparticles and controlling the electrical resistance, infrared absorption characteristics, and other properties of the resistance variable portion within appropriate ranges.

[0075] The amount of binder may be adjusted appropriately depending on the type of binder, and may be, for example, 1% or more, more preferably 2% or more, particularly 3% or more, and in some cases 5% or more, preferably 8% or more, expressed as the ratio of the mass of binder to the total amount of particles and binder. The upper limit of this content is not particularly limited, but is 30% or less, and more preferably 20% or less.

[0076] The binders described above are suitable for coordination or adhesion to particles. The binder may be a material other than such adhesive compounds. Examples of such compounds include various resins, specifically polyvinyl alcohol, polyvinyl acetal, polyvinyl pyrrolidone, carboxymethyl cellulose, acrylic resin, polyvinyl acetate, polyethylene terephthalate, polystyrene, polyethylene, etc. In addition, organic solvents, conductive polymers, conductive particles, pH adjusters, colorants, thickeners, surfactants, etc. may also be used depending on the needs of film formation, applications, etc.

[0077] A film or layer containing infrared-absorbing particles and a binder can be formed by spraying, dipping, or the like using a heat-shielding composition. In this case, the binder may be coordinated to the particles by ligand exchange. This liquid-phase film-forming method is suitable for increasing the efficiency and size of device production. This method is also well suited to the fabrication of flexible devices using flexible resin substrates. However, the method is not limited to this, and the heat-shielding film and its constituent layers may also be formed by sputtering or other vapor-phase film-forming methods.

[0078] The binder may also be configured to function as an acceptor by being subjected to a modification treatment such as laser treatment.

[0079] (heat-shielding film) As described above, the heat-shielding film includes, for example, infrared-absorbing particles that absorb infrared rays to generate electrons and holes, and acceptors that can accept the electrons or holes from the particles. The heat-shielding film includes i) a charge-generation layer that includes the particles and a charge-receiving layer that includes the acceptor, where the charge-generation layer and the charge-receiving layer are in contact with each other, or ii) a monolayer film that includes the particles and the acceptor. As described above, the heat-shielding film is formed as a monolayer film or a multilayer film that includes infrared-absorbing particles, an acceptor, and a binder. Furthermore, ii) the monolayer film that includes the particles and the acceptor is formed as iia) a mixed film formed by simply mixing the particles and the acceptor, or iib) a film that includes the particles and the acceptor that are bonded to each other, more specifically, that are integrated by being chemically or physically bonded to each other.

[0080] The heat-shielding film may have a light transmittance at a wavelength of 700 nm of 25% or more, more preferably 30% or more, and particularly preferably 50% or more.

[0081] (Heat-shielding composition) The heat-shielding composition for forming the heat-shielding film can be prepared as a one-component or multi-component type depending on the configuration and material of the heat-shielding film. The heat-shielding composition includes, for example, infrared-absorbing particles that absorb infrared rays to generate electrons and holes, and an acceptor that can accept the electrons or holes from the particles. The heat-shielding composition has iii) a first composition including the particles and a second composition including the acceptor, or iv) a composition including the particles and the acceptor. Furthermore, iv) the composition including the particles and the acceptor is iva) a mixture in which the particles and the acceptor are simply mixed, or ivb) a composition in which the particles and the acceptor are bonded to each other, more specifically, integrated by chemical or physical bonding. In either case, the binder can also be prepared as a separate composition, i.e., as a third composition, for example.

[0082] [Base material] There are no limitations on the shape and material of the substrate as long as it can support the shielding film. The shielding film may be either light-transmitting or non-light-transmitting. The light-transmitting substrate may be a glass plate, a resin plate, or a resin film.

[0083] [Application example] Examples of application to actual products will be described with reference to Figures 10 to 12. The double glazing shown in Figure 10 comprises a pair of glass plates 15 and 25 arranged at a distance from each other, and a heat shielding film 10 is formed on the surface of one of the glass plates 15 facing the interlayer 40. The interlayer 40 is, for example, an air layer that is shielded from the outside. The interlayer 40 may be a reduced pressure layer or a layer filled with an inert gas. The glass plates 15 and 25 may be resin plates.

[0084] The heat shielding sheet shown in FIG. 11 comprises a translucent resin sheet 35 and a heat shielding film 10, and further comprises an adhesive layer 30 that covers the heat shielding film 10. The resin sheet 35 may be a flexible sheet. The adhesive layer 30 is formed to attach the heat shielding sheet to another substrate. FIG. 12 shows the adhesive layer 30 attached to a glass plate 15. This application example has the advantage that the heat shielding film can be easily fixed at a desired position.

[0085] 10 to 12 show examples in which a light-transmitting substrate is used, but the present invention can also be applied to a non-light-transmitting substrate. Furthermore, the location in which the present invention is used is not limited to an opening in which double-glazed glass is placed. For example, a partition wall around an industrial furnace that is heated to a high temperature of about 1000°C or more and emits a large amount of infrared radiation is one location in which it is desirable to place the above-mentioned heat-shielding film. The formation of a heat-shielding film in such a location that reaches high temperatures may be carried out by applying the above-mentioned heat-shielding composition.

[0086] The present invention will be further described below with reference to examples, but the following description is not intended to limit the present invention to specific examples.

[0087] Example 1 A tin oxide film was formed by the sol-gel method on an ITO substrate, which was a glass plate on which an ITO film had previously been formed as a transparent electrode, and a CdS layer with a thickness of 500 nm was formed on top of that by RF sputtering.

[0088] Next, a solution for forming a charge-generation layer containing CuS nanoparticles was prepared. 0.246 g of copper acetate and 20 ml of oleylamine were placed in three-way flask A and evacuated while stirring. Flask A was then heated using an oil bath to raise the liquid temperature to 160°C and maintained at that temperature for 1 hour. The temperature increase rate was 8°C / min. Meanwhile, 0.096 g of sulfur and 30 ml of 1-octadecene were placed in another three-way flask B. While stirring, the solution was repeatedly evacuated and replaced with nitrogen gas, after which nitrogen gas was introduced to maintain a nitrogen gas atmosphere. Flask B was then heated using an oil bath to raise the liquid temperature to 160°C, dissolving the sulfur. The temperature increase rate was 5°C / min. Flask B was then left for 1 hour, after which nitrogen gas was introduced to maintain a nitrogen gas atmosphere.

[0089] The contents of Flask A were transferred to a centrifuge tube, and the contents of Flask B were added to the centrifuge tube using a syringe and held for 10 minutes. The heater was then turned off, and after the liquid temperature had dropped to 40°C, approximately 30 ml of hexane was added to the centrifuge tube. After visually confirming that the solids had dissolved, 30 ml of ethanol was added and the tube was centrifuged at 2000 rpm for 5 minutes to collect the precipitate. The precipitate was then dissolved in 5 ml of octane, and 30 ml of ethanol was added again. The tube was centrifuged again at 2000 rpm for 5 minutes to collect the precipitate. The mass of the precipitate was measured, and based on this, octane was added to a concentration of 200 mg / ml, and copper sulfide nanoparticles were dispersed to obtain a first ink.

[0090] The first ink contains copper sulfide nanoparticles and oleylamine, a compound capable of coordinating with the copper sulfide nanoparticles. Thermogravimetric analysis (TGA) of the precipitate revealed that the mass ratio of oleylamine to the total mass of the copper sulfide nanoparticles and oleylamine was 10%.

[0091] Then, 50 μl of the first ink was applied onto the CdS layer using a spin coater to obtain a coating film. Note that the concentration of the first ink was adjusted to 50 mg / ml when applied.

[0092] A 200 μl solution (second ink) containing EDT (ethylenedithiol) was applied onto the coating using a spin coater to obtain a thin film that functions as a heat-shielding film. The solvent for this solution was octane, and the concentration of EDT (ethylenedithiol) was 0.3% by mass. Upon contact with the second ink, at least a portion of the compound coordinated to the copper sulfide nanoparticles was replaced from oleylamine (first compound) to EDT (ethylenedithiol) (second compound, binder).

[0093] An additional coating was formed on this coating in the same manner as above using Ink 1, and then the compound was replaced in the same manner as above using Ink 2. This resulted in a thicker charge generating layer.

[0094] Next, gold was vapor-deposited onto a portion of the surface of the charge generation layer to form a metal electrode. The metal electrode was formed with a thickness of approximately 300 nm and covered less than 5% of the surface of the charge generation layer. One conductive wire was fixed to each of the ITO (transparent electrode) and metal electrode of the heat-shielding device using a conductive adhesive, and a 1 kΩ resistor was connected between the two conductive wires to form an external circuit.

[0095] An experiment was conducted in which the heat-shielding device was irradiated with infrared light while connected to an external circuit. Light from an AM1.5 simulated solar light source (100 mW) was passed through a bandpass filter, and only light with wavelengths of 600 nm or longer was irradiated onto the heat-shielding device. A black body was placed at a position where the light transmitted through the heat-shielding device was absorbed, and the temperature change between the heat-shielding device and the black body was measured. Temperature change measurements were conducted with the heat-shielding device connected to an external circuit, with the heat-shielding device not connected to an external circuit, and with the black body irradiated directly with light without the heat-shielding device. Table 1 shows the temperature rise over 10 minutes from the start of irradiation.

[0096] [Table 1]

[0097] It was confirmed that releasing electric charge from the heat-shielding device to the outside effectively blocks incoming infrared rays and also suppresses the temperature rise of the heat-shielding device itself.

[0098] Example 2 A heat-shielding device was prepared in the same manner as in Example 1, except that hydrazine was used instead of EDT to replace at least a portion of the compounds coordinated to the copper sulfide nanoparticles with hydrazine (second compound, binder) instead of oleylamine (first compound), and measurements were performed under the same conditions as in Example 1. In Example 2, measurements were also performed with the heat-shielding device connected to earth instead of an external circuit. This measurement was performed with both the ITO and metal electrodes connected to earth. The results are shown in Table 2.

[0099] [Table 2]

[0100] In Example 2 as well, it was confirmed that discharging electric charges from the heat shielding device to the outside effectively shields the incoming infrared rays and also suppresses the temperature rise of the heat shielding device itself.

[0101] (Example 3) (Comparative Example 1) Ga2O3 nanoparticles were prepared using a method similar to that previously reported (J. AM. CHEM. SOC. 2010, 132, 9250-9252). An octane solution (50 mg / mL) of Ga2O3 nanoparticles was spin-coated onto an FTO substrate, a glass plate with a pre-formed FTO film as a transparent electrode, and the substrate was washed with acetonitrile. This process was repeated twice, and then an octane solution (50 mg / mL) of CWO nanoparticles was spin-coated onto the Ga2O3 nanoparticle film and washed with acetonitrile. This process was repeated five times to prepare a CWO nanoparticle and Ga2O3 nanoparticle laminated film. The resulting laminated film was heated at 450°C for 30 minutes in air to remove the ligands. The baked laminated film was baked at 450°C for 2 hours in a reducing atmosphere (4% hydrogen-containing argon atmosphere) to obtain the heat-shielding device of Example 3. A heat-shielding device of Comparative Example 1 was also prepared in the same manner as Example 3, except that the Ga2O3 nanoparticle film was not applied.

[0102] Using the above two heat-shielding devices, the temperature change 5 minutes after the start of irradiation was measured for the blackbody and the heat-shielding device in the same manner as in Example 2. However, in Example 3, only earth connection was selected, and in Comparative Example 1, measurement when connected to an external circuit was omitted. The results are shown in Table 3. Note that, as in Examples 1 and 2, in Example 3, the temperature rise was further suppressed by connecting to an external circuit.

[0103] [Table 3]

[0104] (Example 4) (Comparative Example 2) Next, a solution for forming a charge generation layer containing Cu7S4 nanoparticles was prepared. First, 1.891 g of copper acetate, 1.13 g of 1,3-dibutyl-2-thiourea, and 10 ml of oleylamine were added to a three-necked flask and the atmosphere was purged with nitrogen while stirring. Next, the liquid temperature was raised to 80°C using a mantle heater and maintained for 1 hour. After the liquid temperature had dropped to 40°C, 40 ml of chloroform was gradually added to the three-necked flask to dissolve the solids.

[0105] The contents of the three-way flask were transferred to a centrifuge tube. After confirming that the solids were fully dissolved in the centrifuge tube, 40 mL of ethanol was added. The tube was then centrifuged at 2000 rpm (revolutions per minute) for 10 minutes, and the supernatant was immediately discarded. The precipitate was then dissolved in 5 mL of octane, after which 30 mL of ethanol was added again and the tube was centrifuged again at 2000 rpm for 5 minutes to collect the precipitate. The mass of the precipitate was measured, and based on this, octane was added to make the concentration 200 mg / mL. The copper sulfide nanoparticles were dispersed in the tube, and the first ink was obtained.

[0106] The first ink contains copper sulfide nanoparticles and oleylamine, a compound capable of coordinating with the copper sulfide nanoparticles. Thermogravimetric analysis (TGA) of the precipitate revealed that the mass ratio of oleylamine to the total mass of the copper sulfide nanoparticles and oleylamine was 10%.

[0107] As in Example 1, a coating film was formed by spin-coating the first ink onto a CdS layer formed on an ITO substrate previously laminated with zinc oxide using a high-frequency sputtering method using a CdS target. Then, 200 μL of a solution (second ink) containing EDT (ethylenedithiol) was applied onto the coating film using a spin coater to obtain a thin film functioning as a heat-shielding film. An additional coating film was formed on this coating film using the same film formation method as above using the first ink, and then compound substitution was performed using the second ink in the same manner as above. A thick charge generation layer was thus formed, yielding the heat-shielding device of Example 4. A heat-shielding device of Comparative Example 2 was also obtained in the same manner as Example 4, except that the CdS layer was not provided.

[0108] Using the above two heat-shielding devices, the temperature change 5 minutes after the start of irradiation was measured for the blackbody and the heat-shielding device in the same manner as in Example 2. However, in Example 4 and Comparative Example 2, measurements when connected to an external circuit were omitted. The results are shown in Table 4. Note that, as in Example 1, in Example 4, the temperature rise was further suppressed by connecting to an external circuit.

[0109] [Table 4]

[0110] It was confirmed that, compared with Comparative Examples 1 and 2, which consisted only of infrared absorbing particles and did not contain acceptors, in Examples 3 and 4, the temperature rise of the device was effectively suppressed.

[0111] Example 5 A heat-shielding device was prepared in the same manner as in Example 4, except that hydrazine was used instead of EDT, and measurements were carried out under the same conditions as in Example 2. In Example 5, measurements were also carried out with the heat-shielding device connected to an external circuit or earth. The results are shown in Table 5.

[0112] [Table 5]

[0113] In Example 5 as well, it was confirmed that when electric charges are released from the heat shielding device to the outside, the incoming infrared rays are effectively shielded and the temperature rise of the heat shielding device itself can also be suppressed.

[0114] Example 6 A mixture of copper sulfide (CuS) nanoparticles dissolved in octane at a concentration of 100 mg / mL and CdS nanoparticles dissolved in octane at a concentration of 100 mg / mL (third ink) was prepared and used as the third ink. Similar to the first ink in Example 1, the third ink also contains oleylamine.

[0115] As in Example 1, a coating film was formed by spin-coating the third ink onto a CdS layer formed on an ITO substrate previously coated with zinc oxide using a high-frequency sputtering method using a CdS target. A 200 μL solution (fourth ink) containing hydrazine was applied onto the coating film using a spin coater to obtain a thin film that functions as an infrared-responsive sensor. The solvent for this solution was octane, and the hydrazine concentration was 0.3 mass%. Upon contact with hydrazine, at least a portion of the compound coordinated to the copper sulfide nanoparticles was replaced from oleylamine (first compound) coordinated during nanoparticle synthesis with hydrazine (second compound, binder). Thereafter, a heat-shielding device was fabricated in the same manner as in Example 1, and similar measurements were performed. In Example 6, measurements were also performed with the heat-shielding device connected to an external circuit or ground. The results are shown in Table 6.

[0116] [Table 6]

[0117] In Example 6, which used a single-layer film containing infrared absorbing particles and acceptor particles, it was also confirmed that releasing charges from the heat-shielding device to the outside effectively blocks incoming infrared rays and also suppresses the temperature rise of the heat-shielding device itself.

[0118] Example 7 ITO nanoparticles were synthesized using the same method as previously reported (Nano Letters, 2019, 19, 11, 8149-8154). Subsequently, tin oxide was grown on the surface of the ITO nanoparticles using the seed-mediated growth method to obtain composite particles of ITO and tin oxide. The composite was achieved by growing a SnO layer on the ITO nanoparticles using a previously reported method (Materials Chemistry and Physics Volume 166, September 15, 2015, Pages 87-94). Subsequently, an ITO / SnO film was spin-coated on a substrate using the same ink-based film-forming method as in Example 1, but with hydrazine instead of EDT, as in Example 2. A heat-shielding device was then fabricated and similar measurements were performed as in Example 1. The results are shown in Table 7.

[0119] [Table 7]

[0120] Example 8 The temperature change over time when irradiated with infrared rays was investigated for a heat-shielding device obtained in the same manner as in Example 1. However, the distance from the filter to the heat-shielding device was greater than in Example 1. The results are shown in Figure 13. When not connected to an external circuit (Figure 13 "Not connected"), the temperature of the device stabilized in about 4 minutes, with the temperature rise being 0.7 to 0.8°C. In contrast, when the device was connected to an external circuit (resistance 1 kΩ), the temperature rose more slowly. With this device, it took about 8 minutes for the temperature to stabilize, and the temperature rise was limited to 0.5°C.

[0121] The light transmittance at a wavelength of 700 nm of each heat-shielding film was measured, and was found to be at least 24% in all of the examples. Specifically, the light transmittance at a wavelength of 700 nm of the heat-shielding film of Example 1(8) was 52%. The light transmittance at a wavelength of 700 nm of the heat-shielding films of the other examples was 50% for Example 2, 45% for Example 3, 25% for Example 4, 83% for Example 5, 50% for Example 6, and 90% for Example 7. The light transmittance at a wavelength of 600 nm of the heat-shielding film of Example 1(8) was 67%. The light transmittance at a wavelength of 600 nm of the heat-shielding films of the other examples was 65% for Example 2, 57% for Example 3, 20% for Example 4, 82% for Example 5, 65% for Example 6, and 90% for Example 7.

[0122] Example 9 The degree of promotion of the methylene blue fading reaction by charge carriers was evaluated using a shielding device with a CuS / CdS laminated shielding film according to Example 2 and a shielding device containing a CuS-CdS mixed monolayer film according to Example 6. This evaluation was performed by immersing the shielding device in a cell containing an aqueous solution of methylene blue, irradiating it with infrared light, and measuring the change in absorbance due to methylene blue. However, this measurement was performed without connecting the electrodes to an external circuit. As described above, the cell was irradiated with infrared light with a wavelength of 600 nm or greater, obtained by passing light from an AM1.5 simulated solar light source (100 mW) through a bandpass filter. Figure 14 shows the change over time in the absorption spectrum of the shielding device containing the CuS-CdS mixed monolayer film over 5 hours. Figure 15 also shows the change over time in the absorption peak intensity using both shielding devices. These figures suggest that holes (positive holes) generated in the shielding film by infrared irradiation generated active species such as hydroxyl radicals, which decomposed methylene blue. [Industrial Applicability]

[0123] The device according to the present invention can be used in a wide range of fields as a heat-shielding device, or a so-called "heat-dissipating" device, which emits a portion of the absorbed infrared energy as an electric charge to the outside of the device. The direction and amount of the emitted electric charge can be controlled much more easily than heat. The present invention is useful, but is not particularly limited to, for example, as a "heat-dissipating" technology for placement in openings in buildings and vehicles, around melting furnaces heated to high temperatures, etc., or for mitigating temperature increases in electronic devices.

Claims

1. A heat-shielding device that blocks at least a portion of irradiated infrared rays, a heat-shielding film including particles that absorb the infrared rays to generate electrons and holes, and acceptors that receive the electrons or the holes from the particles; At least a portion of the charge carriers selected from the electrons and the holes is emitted from the heat-shielding film to the outside of the heat-shielding device, The exterior includes a first exterior that is a gas or a liquid and a second exterior that is a solid, At least a portion of the electrons and the holes are released by oxidizing or reducing the first external chemical species; At least a portion of the other selected from the electrons and the holes is released by conduction to the second outside. Heat shielding device.

2. A heat-shielding device that blocks at least a portion of irradiated infrared rays, a heat-shielding film including particles that absorb the infrared rays to generate electrons and holes, and acceptors that receive the electrons or the holes from the particles; At least a portion of the charge carriers selected from the electrons and the holes is emitted from the heat-shielding film to the outside of the heat-shielding device, the external part is other than a circuit including at least one of an inverter, an electricity storage device, a voltmeter, and an ammeter; a conductive portion for discharging the charge carriers to the outside, the conductive portion is electrically connected to the outside other than the circuit; Heat shielding device.

3. A heat-shielding device that blocks at least a portion of irradiated infrared rays, a heat-shielding film including particles that absorb the infrared rays to generate electrons and holes, and acceptors that receive the electrons or the holes from the particles; At least a portion of the charge carriers selected from the electrons and the holes is emitted from the heat-shielding film to the outside of the heat-shielding device, Further provided with a non-transparent electrode, the area where the electrode is formed is less than 50% of the light receiving area where the infrared light is incident on the device; Heat shielding device.

4. A heat-shielding device that blocks at least a portion of irradiated infrared rays, a heat-shielding film including particles that absorb the infrared rays to generate electrons and holes, and acceptors that receive the electrons or the holes from the particles; At least a portion of the charge carriers selected from the electrons and the holes is emitted from the heat-shielding film to the outside of the heat-shielding device, the heat-shielding film includes a charge generating layer containing the particles and a charge receiving layer containing the acceptor, the charge generating layer and the charge receiving layer being in contact with each other; Heat shielding device.

5. A heat-shielding device that blocks at least a portion of irradiated infrared rays, a heat-shielding film including particles that absorb the infrared rays to generate electrons and holes, and acceptors that receive the electrons or the holes from the particles; At least a portion of the charge carriers selected from the electrons and the holes is emitted from the heat-shielding film to the outside of the heat-shielding device, the heat shielding film is a single layer film including the particles and the acceptor, the particle and the acceptor are bound to each other; Heat shielding device.

6. The heat shielding device according to any one of claims 1 to 5, wherein the heat shielding film has a light transmittance of 24% or more at a wavelength of 700 nm.

7. 4. The heat shielding device according to claim 1, wherein the heat shielding film comprises a charge generation layer containing the particles and a charge acceptance layer containing the acceptor, the charge generation layer and the charge acceptance layer being in contact with each other.

8. 4. The heat shielding device according to claim 1, wherein the heat shielding film is a single layer film containing the particles and the acceptor.

9. The heat shielding device of claim 8 , wherein the particles and the acceptors are bonded to each other.

10. The heat shielding device according to any one of claims 1 to 5, wherein the particles comprise a material capable of absorbing infrared radiation through localized surface plasmon resonance.

11. The heat shielding device of claim 10 , wherein the particles are inorganic particles.

12. A heat-shielding film that blocks at least a portion of irradiated infrared rays, particles that absorb the infrared light to generate electrons and holes; and acceptors that can receive the electrons or the holes from the particles; i) a charge generating layer comprising the particles and a charge receiving layer comprising the acceptor, the charge generating layer and the charge receiving layer being in contact with each other; or ii) a monolayer film comprising the particle and the acceptor, wherein the particle and the acceptor are bound to each other; Heat-shielding film.

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