WO2022124283A1

WO2022124283A1 - Photoelectric conversion device, building, and mobile object

Info

Publication number: WO2022124283A1
Application number: PCT/JP2021/044823
Authority: WO
Inventors: 晃石橋; 隆志松岡
Original assignee: 国立大学法人北海道大学
Priority date: 2020-12-10
Filing date: 2021-12-07
Publication date: 2022-06-16

Abstract

This photoelectric conversion device comprises: a light receiving unit (10); a photoelectric conversion unit composed of an intermediate band-type solar cell (20), which is spatially separated from the light receiving unit (10); and a spatially asymmetric waveguide (13) which connects the light receiving unit (10) and the photoelectric conversion unit and has a function of converting the travel direction of light, wherein the photoelectric conversion unit is provided at the end of the waveguide (13) on the light emitting side, and the direction of light emitted from the end of the waveguide (13) on the light emitting side is substantially parallel to a semiconductor layer (21) constituting the intermediate band-type solar cell (20).

Description

Photoelectric converters, buildings and mobiles

The present invention relates to photoelectric conversion devices, buildings and moving objects, for example, windows, walls, roofs and displays of various electronic devices of various buildings such as buildings and houses, small unmanned machines moving in the air and automobiles, and the like. The present invention relates to a photoelectric conversion device suitable for being installed on the outer surface of various moving bodies of the above and used as a solar cell, and a building and a moving body using this photoelectric conversion device.

Solar systems require vast amounts of land. According to estimates, 5 acres (about 20235 m ² ) of land is required per megawatt, and there are concerns about land deterioration and habitat destruction of animals and plants depending on the location. Especially in Japan, where there are many mountainous areas, it is fresh in my memory that the danger of landslides and landslides when there is a lot of rainfall cannot be ignored. Also, unlike wind power, it is almost impossible to use agricultural land for solar power at the same time. Acquisition of business land for solar power generation has become a major issue. Conventionally, when converting light from a light source having a wide spectrum into electrical energy, an intermediate band type solar cell (Intermediate-) that expands the absorption wavelength band by providing another band called an intermediate band in the band gap of the host semiconductor. band Solar Cell (IBSC) is known (see Non-Patent

Documents

1, 2 and 3). In this intermediate band type solar cell, although the effect of the existence of the intermediate band can be seen, the conversion efficiency in the region where the original band gap contributes to power generation is lowered (see Non-Patent Document 4). For this reason, effective results have not always been obtained in actual devices.

In the conventional intermediate band type solar cell, the direction of light incident and the traveling direction of the photocarrier are arranged parallel to each other. It is known that the conversion efficiency of an intermediate band type solar cell largely depends on the intersubband absorption coefficient α _IB . When α _IB = 1000 cm ^-1 , the theoretical conversion efficiency can be 40%, and α _IB = 10000 cm. In the case of ^-1 , the conversion efficiency of 50% is also possible (see Non-Patent Document 5).

In the intermediate band type solar cell, it is necessary to keep the lifetime of electrons and holes remaining in the intermediate gap level above a certain level. Otherwise, the level consumes the photocarriers generated in the wide-gap region and makes only a detrimental contribution, such as a mere non-luminous level. The problem is to suppress recombination via a structure that causes an intermediate bandgap (for example, a quantum dot structure) (see Non-Patent Document 6).

Quantum dots are used as semiconductors that form intermediate bands, but they have a dot-like structure due to distortion, and the thickness of the intermediate bandgap layer must be extremely large due to constraints on growth time and crystal quality. Is not easy.

On the other hand, if the quantum well layer is too thin, light absorption cannot be obtained significantly. Therefore, in an arrangement in which the traveling direction of light and the traveling direction of photocarriers are parallel to each other, the above two requirements become contradictory.

In the intermediate band type solar cell in which the direction of light incident and the traveling direction of the photocarrier are parallel to each other, the feasibility of high photoelectric conversion efficiency originally possessed by the intermediate band type solar cell cannot be fully utilized. Further, in the conventional intermediate band type solar cell, a plurality of intermediate gap values cannot be prepared in the lateral direction of crystal growth.

A waveguide-coupled photoelectric conversion device in which the light harvesting section (light receiving section) and the photoelectric conversion section are separated from each other and the two are coupled by a waveguide, and the light incident direction and the traveling direction of the photocarrier are perpendicular to each other. Although proposed by the present inventor (see Patent Documents 1 and 2), since each power generation unit generates a different output voltage, in order to obtain a constant output voltage, two similar structures are formed and the output voltage is obtained. It was necessary to take measures such as connecting the large ones and the small ones in series.

The waveguide coupled photoelectric conversion device proposed in

Patent Documents

1 and 2 is expected to enable highly efficient photovoltaic power generation, but the light traveling direction conversion for obliquely incident sunlight in the morning and evening is applied to the total incident angle. Therefore, no effective result has been obtained especially for an intermediate incident angle of 30 to 50 °.

Although a line-and-space structure or a parabolic structure with a parabolic cross section is used for the conventional light traveling direction conversion layer, it is not easy to collect the refracted light at the focal point of the parabolic curve (see Patent Document 1). Therefore, after the refracted light is reflected on the parabola surface, it is very difficult to make the light parallel to the parabolic axis. Therefore, it was also difficult to realize vertical incident on the two-dimensional waveguide behind the optical traveling direction conversion layer.

In the photoelectric conversion device proposed in

Patent Documents

1 and 2, the efficiency can be improved by converting the three-dimensional space propagating light (3D light) into a planar waveguide light (2D light), but the structure performs 3D-2D conversion. It was not easy to make the product at low cost.

As described above, conventional solar cells or photoelectric conversion devices have not been able to realize a photovoltaic power generation system having high photoelectric conversion efficiency, easy to manufacture, and inexpensive.

International Publication No. 2017/0614848 International Publication No. 2019/059342

As mentioned above, the conventional intermediate band type solar cell has not been able to fully demonstrate its potential performance.

Therefore, the problem to be solved by the present invention is that the potential of the intermediate band type solar cell capable of improving the efficiency of high photoelectric conversion can be fully exhibited, and the light receiving unit and the photoelectric conversion unit are separated from each other. A photoelectric conversion device capable of realizing the high photoelectric conversion efficiency inherent in the waveguide coupled photoelectric conversion device and efficiently converting light from a light source having a wide spectrum into electric power, and a building having this photoelectric conversion device. And to provide a moving body.

In order to solve the above problems, the present invention
Light receiving part and
A photoelectric conversion unit composed of an intermediate band type solar cell, which is spatially separated from the light receiving unit,
A spatially asymmetric waveguide that connects the light receiving unit and the photoelectric conversion unit and has a function of converting the traveling direction of light.
Have,
The photoelectric conversion unit is provided at the end of the waveguide on the light emitting side.
This is a photoelectric conversion device configured so that the direction of light emitted from the end of the waveguide on the light emitting side is substantially parallel to the semiconductor layer constituting the intermediate band type solar cell.

The intermediate band of the intermediate band type solar cell is formed of, for example, a semiconductor having a single or multiple quantum well structure, a semiconductor having a quantum dot structure, or the like. In particular, when the host semiconductor of the intermediate band type solar cell is a GaN-based semiconductor, a GaInN-based semiconductor is preferably used as the semiconductor forming such an intermediate band.

In this photoelectric conversion device, preferably, the light receiving portion has a light traveling direction conversion layer that converts the traveling direction of the light incident on the light receiving portion into a direction substantially perpendicular to the light receiving portion. The light traveling direction changing layer is preferably a transparent base material having a first refractive index and a transparent base material having a first refractive index provided in a two-dimensional array on one main surface of the transparent base material. It has a plurality of rotating release object-like portions made of a material, and a surface made of a hemisphere provided so as to cover each rotating release object-like portion, and has a second refractive index smaller than the first refractive index. It has a hemispherical portion, and the focal point of the rotating object-shaped portion and the center of the hemispherical portion coincide with each other.

The above-mentioned waveguide is configured so that the direction of the light emitted from the end of the waveguide on the light emitting side is substantially parallel to the semiconductor layer constituting the intermediate band type solar cell. For example, the above-mentioned waveguide is provided between a two-dimensional waveguide having continuous parallel anisotropy with respect to the waveguide direction and the above-mentioned optical traveling direction conversion layer. Refractive index that asymmetrically propagates light whose traveling direction is changed in a direction substantially perpendicular to the light receiving surface of the light receiving portion by the light traveling direction changing layer in only one direction parallel to the light receiving surface when viewed locally. It is composed of a waveguide structure having discrete translational symmetry having an anisotropic layer having at least a part thereof. This waveguide structure contains, for example, a plurality of liquid crystal layers having different coordinating directions (directions of directors) from each other in at least a part thereof, or a plurality of isotropic structures separated by non-parallel interfaces. It includes, but is not limited to, at least a portion of the medium. In general, the overall shape of the waveguide is not particularly limited, and may be a planar shape or a curved surface shape, for example, a cylindrical shape, a semicircular spherical shape (dome shape), a corrugated plate shape, or the like. By forming a cylindrical shape using a two-dimensional waveguide as a waveguide, it is possible to install a photoelectric conversion device on the side surface of the cylinder, for example. Further, by forming the two-dimensional waveguide in a semicircular shape, it is possible to install the photoelectric conversion device on the top of the semicircular spherical shape of a cylinder, for example. A two-dimensional waveguide may be formed in the shape of a corrugated sheet, and a photoelectric conversion device may be installed on the outer wall of the building. When these cylindrical, hemispherical or corrugated two-dimensional waveguides are used, a high-reflectance white paint is applied to the inner surface (the surface facing the installation surface of the photoelectric conversion device) to form a white high-reflectance layer. By forming the above, the light incident on the two-dimensional waveguide can be efficiently waveguideed in the two-dimensional waveguide.

In this photoelectric conversion device, the light receiving portion and the waveguide can be configured as follows, for example (see Patent Document 2). That is, the light receiving part and the waveguide are
A waveguide core layer with continuous translational symmetry with respect to the waveguide direction,
The waveguide core layer is discontinuously covered, and has a clad layer having discrete translational symmetry with respect to the waveguide direction.
The clad layer is separated from the waveguide core layer at the end of the breaking portion that does not cover the waveguide core layer, on the side opposite to the waveguide direction of the waveguide core layer with respect to the cutting portion, and away from the waveguide core layer. It extends between the positions and gradually approaches the waveguide core layer toward the waveguide direction of the waveguide core layer, and the tangent line at the end of the disconnection portion is parallel to or substantially equal to the waveguide core layer. It has a structure provided in parallel as a part of it,
A light-introduced core layer coated with the clad layer is provided at the discontinuity of the clad layer so as to join the waveguide core layer. With this configuration, the waveguide core layer has a structure that is asymmetric with respect to the waveguide direction and the opposite direction of the light inside the waveguide core layer. Typically, the waveguide core layer has continuous translational symmetry with respect to the waveguide direction, and the clad layer has discrete translational symmetry with respect to the waveguide direction. Typically, a plurality of cutout portions of the clad layer are provided at equal intervals in the waveguide direction of the waveguide core layer, and a light introduction core layer is provided in each cutoff portion. The spacing between the breaks is chosen as needed. Preferably, the light-introduced core layer and the clad layer covering the light-introduced core layer are a waveguide core in which the light introduced into the light-introduced core layer is repeatedly totally reflected at the interface between the light-introduced core layer and the clad layer. Provided to reach the layer. Typically, the shape of the cross section of the clad layer extending from the end of the break that is perpendicular to the plane of the waveguide core layer and parallel to the waveguide direction of the waveguide core layer leads to the waveguide of the waveguide core layer. It has a concavely curved shape in the wave direction (more accurately, a part of the concavely curved shape in the waveguide direction of the waveguide core layer). This shape is, for example, a combination curve containing at least a part of an arc or an ellipse, or a part of an ellipse (vertical ellipse) whose major axis is perpendicular to the waveguide direction of the waveguide core layer, and the major axis is derived. It consists of an ellipse (horizontally oblong ellipse) parallel to the waveguide direction of the wave core layer or a combination curve with a part of an arc. More specifically, this shape can be, for example, the shape of a quarter circle arc, the shape of a quarter arc divided by the major and minor axes of an ellipse, or a curve created by combining these. For example, it may be as follows. That is, this shape is the first one consisting of a quarter divided by the major axis and the minor axis of an ellipse (longitudinal ellipse) whose major axis is perpendicular to the waveguide direction of the waveguide core layer on the light incident surface side. The arc and the major axis from a quarter divided by the major axis and the minor axis of an ellipse (horizontally oblong ellipse) whose major axis is parallel to the waveguide direction of the waveguide core layer connected to this first arc. It may be composed of a second arc obtained by cutting a portion having a predetermined length from the intersection, and may be concavely curved in the waveguide direction of the waveguide core layer as a whole. Alternatively, this second arc may be a part cut from a quarter of a circle having a large radius in the same manner as the above ellipse. Here, typically, the semimajor axis of the vertically elongated ellipse (1/2 of the length of the major axis) is about 6 to 100 μm, the semimajor axis of the horizontally elongated ellipse is about 100 μm to 3 mm, or a quarter of the above radius. The radius of one circle is about 300 μm to 10 mm. In this case, preferably, a relatively thick clad layer is periodically included in the repeating structure of the light-introduced core layer and the clad layer. The period in which this relatively thick clad layer appears and the width (thickness in the cross section) of this relatively thick clad layer and the relatively thin clad layer are incident into the light introduction core layer while minimizing the loss as a whole. It is appropriately selected so that light can be propagated and guided to the waveguide core layer.

In this photoelectric conversion device, the light receiving portion and the waveguide can be configured as follows, for example. That is, the light receiving part and the waveguide are
A flat-plate reflector array in which a plurality of reflectors are periodically arranged in one direction via a transparent layer, one main surface constitutes a light incident surface and the other main surface constitutes a light emitting surface.
The incident light is guided in one direction by being provided on the other main surface of the reflector array and incident on the one main surface of the reflector array from the outside and reflected by the reflector. Asymmetric planar optical waveguides configured as
Have. Then, the above-mentioned light traveling direction changing layer is provided on the light incident surface of the reflecting mirror array. As the reflector array, for example, the one described in Patent Document 1 can be used. The cross-sectional shape and arrangement of the reflectors in the reflector array is that the light whose traveling direction is changed in the direction perpendicular to the light traveling direction conversion layer directly hits the asymmetric planar optical waveguide through the light traveling direction conversion layer. It is set so that the light reflected by one reflector is not incident on the adjacent reflector and scattered. Other things are the same as in Patent Document 1. The asymmetrical optical waveguide typically has a wedge-shaped (or tapered) shape in which the cross-sectional area gradually increases toward the end face on the light emitting side. In such a wedge-shaped asymmetrical optical waveguide, the light incident inside from the light incident surface of the asymmetrical planar optical waveguide is alternately reflected by the two main surfaces of the asymmetrical planar optical waveguide to have a cross-sectional area. It is waveguide in a larger direction and finally incident on a photoelectric conversion unit (power generation unit) provided at the end on the light emitting side of the asymmetric planar optical waveguide. The asymmetric plane optical waveguide may be a planar optical waveguide or a curved optical waveguide. Further, the planar shape of the asymmetrical optical waveguide is selected as needed, but typically has a rectangular shape, for example, a rectangular shape or a square shape. In this case, if necessary, the end face of the asymmetric plane optical waveguide excluding the light emitting end face, for example, the asymmetric plane optical waveguide has a quadrangular shape, and at least one of a pair of sides facing each other thereof. When all or part of the end face of the asymmetric planar optical waveguide corresponding to the side is the light emitting end face, it corresponds to at least one side of the pair of sides different from the above-mentioned pair of opposite sides of this quadrangle. A light reflection mechanism is provided at the end of the asymmetric planar optical waveguide. In this case, when the light incident on the main surface of the asymmetric planar optical waveguide is incident on the light reflection mechanism when it is waveguideed in the asymmetric planar optical waveguide, it is reflected and the optical path is bent in the direction toward the light emitting end surface. This increases the amount of light that can be extracted from the light emitting end face. In this light reflection mechanism, for example, a light reflection film provided on the side surface of the asymmetric surface optical waveguide or the side surface of the asymmetric surface optical waveguide is configured as a mirror surface.

The semiconductor layer constituting the intermediate band type solar cell is made of an inorganic semiconductor or an organic semiconductor, and is typically a pn junction composed of a p-type semiconductor layer and an n-type semiconductor layer, and the pn junction surface thereof is a waveguide. It is substantially parallel to the direction of the light emitted from the end of the light emitting side, and has an intermediate band forming layer between the p-type semiconductor layer and the n-type semiconductor layer. The thickness of the semiconductor layer is appropriately selected in consideration of the function of the diffusion length of the carriers in the semiconductor layer, but is preferably 1 μm or more and 500 μm or less. The semiconductor constituting the semiconductor layer may be in any form of amorphous (amorphous), polycrystal, or single crystal.

Examples of the inorganic semiconductor include II-VI group compound semiconductors such as CdSe, PbS, PbSe, and PbTe, III-V compound semiconductors such as GaSb, InAs, InN, AlInN, GaInN, GaN, AlGaN, GaAsN, and GaPN, and Si and SiGe. Group IV semiconductors such as Si _x Gey Sn _1-xy _O , SiN _x , SiO _x , CIS (CuInSe), CIGS (CuInGaSe), CuInGaSeTe and the like can be used. These semiconductors are characterized in that the bandgap can be controlled by, for example, controlling the composition ratio of Group III elements such as In and Ga and mixing sulfur (S). The semiconductor layer can also be composed of fine particles made of these inorganic semiconductors.

As the organic semiconductor, all materials generally reported as materials for organic solar cells can be used, but specifically, polyacetylene such as pentacene, polyacetylene (preferably disubstituted polyacetylene), and poly (p.) -Phenylene vinylene), poly (2,5-thienylene vinylene), polypyrrole, poly (3-methylthiophene), polyaniline, poly (9,9-dialkylfluorene) (PDAF), poly (9,9-dioctylfluorene- co-Bithiophene) (F8T2), Poly (1-hexyl-2-phenylacetylene) (PH _X PA) (light emitting material is blue), Poly (diphenylacetylene) derivative (PDPA-nBu) (Light emitting material) Poly (pyridine) (PPy), poly (pyridylbinylene) (PPyV), cyano-substituted poly (p-phenylene vinylene) (CNPPV), poly (3,9-di-tert- Butyl indeno [1,2-b] fluorene (PIF) and the like can be used. For the dopants of these organic semiconductors, alkali metals (Li, Na, K, Cs) can be used as donors, and as acceptors. Are halogens (Br ₂ , I ₂ , CI ₂ ), Lewis acids (BF ₃ , PF ₅ , AsF ₅ , SbF ₅ , SO ₃ ), transition metal halides (FeCl ₃ , MoCl ₅ , WCl ₅ , SnCl ₄ ). , TCNE and TCNQ can be used as the organic acceptor molecule, and the dopant ions used for electrochemical doping are tetraethylammonium ion (TEA ⁺ ), tetrabutylammonium ion (TBA ⁺ ), and Li ⁺ as cations. , Na ⁺ , K ⁺ , ClO _4- ^, BF _4- ^, PF _6- ^, AsF _6- ^, SbF _6- ^, etc. can be used as the anion. Further, a polymer electrolyte can be used as the organic semiconductor. Specific examples of this polymer electrolyte include polycations such as sulphonate polyaniline, poly (thiophene-3-acetic acid), sulphonate polystyrene, and poly (3-thiophene alkanthulfonate). Examples include polyallylamine, poly (p-phenylene-vinylene) precursor polymer, poly (p-methylpyridinium vinylene), and protonated poly (p-pyridylbinile). , Poloton (2-N-methylpyridinium acetylene) and the like can be used. When an organic semiconductor layer doped with a low impurity concentration is used as the semiconductor layer, the organic semiconductor layer can have a heterojunction type or a bulk heterojunction type structure. In the organic semiconductor layer having a heterojunction structure, the p-type organic semiconductor film and the n-type organic semiconductor film are bonded so as to be in contact with the first electrode and the second electrode. The organic semiconductor layer having a bulk heterojunction structure is composed of a mixture of a p-type organic semiconductor molecule and an n-type organic semiconductor molecule, and has a microstructure in which the p-type organic semiconductor and the n-type organic semiconductor are intertwined with each other and are in contact with each other.

As the semiconductor constituting the semiconductor layer, an organic-inorganic hybrid semiconductor can be used in addition to the inorganic semiconductor and the organic semiconductor. As such an organic-inorganic hybrid semiconductor, for example, a perovskite-based semiconductor can be used.

This photoelectric conversion device can be basically installed in anything, but for example, it is installed in a building, an electronic device, a mobile body, or the like. Here, the building may be basically any building as long as it can be installed with a photoelectric conversion device, but specifically, for example, a building, a condominium, a detached house, or the like. Examples include condominiums, station buildings, school buildings, government buildings, stadiums, stadiums, hospitals, churches, factories, warehouses, huts, bridges, columns (telegraph columns, etc.), towers (advertising towers, etc.). The location where the photoelectric conversion device is installed in these buildings is not particularly limited, and is selected as necessary. Examples of installation locations are glass windows and daylighting sections of these buildings. In this case, the photoelectric conversion device is, for example, a solar cell used as a power source for electric appliances installed in these buildings and the inside thereof. Preferably, the semiconductor layer is arranged in a shadow portion of the building so that the light does not directly enter the semiconductor layer when the light is incident on the main surface of the planar optical waveguide. For example, the planar optical waveguide includes a portion having a gentle curvature, and this portion is arranged, for example, under a roof tile, under a central protruding ridge of a roof, a window frame, or a crosspiece. In addition, the electronic device may be basically any kind, and includes both a portable device and a stationary device. Specific examples include mobile phones, mobile devices, robots, and the like. Personal computers, in-vehicle devices, various home electric appliances, etc. In this case, the photoelectric conversion device is, for example, a solar cell used as a power source for these electronic devices. The moving object may be basically any, but for example, a small unmanned aerial vehicle, an unmanned aerial vehicle, an aircraft, an artificial satellite, an unmanned ship, a ship, an underwater moving object, a rover, or an unmanned vehicle. , Cars, etc. Small unmanned or unmanned aerial vehicles include, for example, drones, radio-controlled aircraft, pesticide spraying helicopters, and the like.

In addition, this invention
It has at least one photoelectric conversion device and has
The above photoelectric conversion device
Light receiving part and
A photoelectric conversion unit composed of an intermediate band type solar cell, which is spatially separated from the light receiving unit,
A spatially asymmetric waveguide that connects the light receiving unit and the photoelectric conversion unit and has a function of converting the traveling direction of light.
Have,
The photoelectric conversion unit is provided at the end of the waveguide on the light emitting side.
It is a building which is a photoelectric conversion device configured so that the direction of the light emitted from the end of the waveguide on the light emitting side is substantially parallel to the semiconductor layer constituting the intermediate band type solar cell.

In the invention of this building, as long as it does not contradict its properties, the above-mentioned invention of the photoelectric conversion device is established.

In addition, this invention
It has at least one photoelectric conversion device and has
The above photoelectric conversion device
Light receiving part and
A photoelectric conversion unit composed of an intermediate band type solar cell, which is spatially separated from the light receiving unit,
A spatially asymmetric waveguide that connects the light receiving unit and the photoelectric conversion unit and has a function of converting the traveling direction of light.
Have,
The photoelectric conversion unit is provided at the end of the waveguide on the light emitting side.
It is a moving body that is a photoelectric conversion device configured so that the direction of light emitted from the end of the waveguide on the light emitting side is substantially parallel to the semiconductor layer constituting the intermediate band type solar cell.

In the invention of this moving body, as long as it does not contradict its properties, the above-mentioned invention of the photoelectric conversion device is established.

According to the present invention, since the entire light receiving unit separated from the photoelectric conversion unit can receive light, the amount of light received can be maximized, and the three-dimensional propagating light thus received can be transmitted in the asymmetric waveguide. Due to the asymmetry of this asymmetric waveguide, it is possible to irreversibly convert it into two-dimensional waveguide light by waveguideing it toward the photoelectric conversion unit (only when going from three-dimensional propagating light to two-dimensional waveguide light). The waveguide light finally emitted from the end of the waveguide can be incidentally incident on the side surface of the semiconductor layer of the intermediate band type solar cell for photoelectric conversion. In this case, the intermediate band type solar cell can widen the absorption wavelength band by having an intermediate band in the band gap of the host semiconductor, so that light from a light source having a wide spectrum such as a solar spectrum is extremely efficient. Can be converted into electrical energy. Then, by applying this photoelectric conversion device to a building such as a house, an energy-saving building can be realized, and by applying it to a moving body such as an automobile, an energy-saving moving body can be realized.

It is sectional drawing which shows the photoelectric conversion apparatus by 1st Embodiment of this invention. It is a top view seen from the light incident side of the photoelectric conversion apparatus by 1st Embodiment of this invention. It is sectional drawing which shows the optical waveguide part of the photoelectric conversion apparatus by 1st Embodiment of this invention. It is sectional drawing which enlarges and shows the vicinity of the cutoff part of the clad layer of the optical waveguide part of the photoelectric conversion apparatus by 1st Embodiment of this invention. It is sectional drawing which enlarges and shows the vicinity of the cutoff part of the clad layer of the optical waveguide part of the photoelectric conversion apparatus by 1st Embodiment of this invention. It is sectional drawing which enlarge | shows a part of the photoelectric conversion apparatus by 1st Embodiment of this invention. It is sectional drawing which shows the specific example of the intermediate band type solar cell of the photoelectric conversion apparatus by 1st Embodiment of this invention. It is a schematic diagram which shows an example of the energy band when the intermediate band of the intermediate band type solar cell of the photoelectric conversion apparatus by 1st Embodiment of this invention is formed by the inclined composition quantum well. It is a schematic diagram which shows the photoluminescence spectrum at the measurement position of the substrate when the inclined composition GaInN layer is grown on the sapphire substrate in order to form the intermediate band shown in FIG. FIG. 3 is a schematic diagram showing a band gap with respect to a position from the center of the substrate when the inclined composition GaInN layer is grown on the sapphire substrate in order to form the intermediate band shown in FIG. It is sectional drawing which shows the optical traveling direction conversion layer used in the photoelectric conversion apparatus by 1st Embodiment of this invention. It is a top view which shows an example of the planar shape of the light traveling direction conversion layer used in the photoelectric conversion apparatus according to 1st Embodiment of this invention. It is a top view which shows the other example of the plane shape of the light traveling direction conversion layer used in the photoelectric conversion apparatus by 1st Embodiment of this invention. It is a schematic diagram which shows the result of the computer simulation of the light field performed on the light traveling direction conversion layer shown in FIGS. 11 and 12. It is a schematic diagram which shows the result of the computer simulation of the light field performed on the light traveling direction conversion layer shown in FIGS. 11 and 12. It is sectional drawing which shows the photoelectric conversion apparatus by the 2nd Embodiment of this invention. It is sectional drawing which shows the optical waveguide part of the photoelectric conversion apparatus by 2nd Embodiment of this invention. It is sectional drawing which enlarges and shows a part of the optical waveguide part of the photoelectric conversion apparatus by 2nd Embodiment of this invention. It is a schematic diagram for demonstrating the cross-sectional shape of the clad layer of the optical waveguide part of the photoelectric conversion apparatus according to the 2nd Embodiment of this invention. It is a schematic diagram which shows the result (optical field) of the simulation performed for verifying the waveguide performance of the optical waveguide part of the photoelectric conversion apparatus by the 2nd Embodiment of this invention. It is a schematic diagram which shows the result (introduction efficiency) of the simulation performed for verifying the waveguide performance of the optical waveguide part of the photoelectric conversion apparatus according to the 2nd Embodiment of this invention. It is sectional drawing which shows the photoelectric conversion apparatus by the 3rd Embodiment of this invention. It is sectional drawing which shows the optical waveguide part of the photoelectric conversion apparatus by the 3rd Embodiment of this invention. It is sectional drawing which shows the part of the optical waveguide part of the photoelectric conversion apparatus according to the 3rd Embodiment of this invention. It is a schematic diagram which shows the result (light field) of the simulation performed for verifying the waveguide performance of the optical waveguide part of the photoelectric conversion apparatus according to the 3rd Embodiment of this invention. It is sectional drawing which shows the waveguide structure used as the optical waveguide part in the photoelectric conversion apparatus according to 4th Embodiment of this invention. It is a schematic diagram which shows the result of the computer simulation of the optical field performed on the waveguide structure shown in FIG. 26. It is sectional drawing which shows the photoelectric conversion apparatus by the 5th Embodiment of this invention. It is sectional drawing which shows the photoelectric conversion apparatus by 6th Embodiment of this invention. It is sectional drawing which shows the photoelectric conversion apparatus by 6th Embodiment of this invention. It is sectional drawing for demonstrating the operation of the photoelectric conversion apparatus according to the 6th Embodiment of this invention. It is sectional drawing which enlarge | shows a part of the optical waveguide part of the photoelectric conversion apparatus by 7th Embodiment of this invention. It is a schematic diagram which shows the result (light field) of the simulation performed for verifying the waveguide performance of the optical waveguide part of the photoelectric conversion apparatus according to the 7th Embodiment of this invention. It is a front view which shows the photoelectric conversion device installation cylinder by the 8th Embodiment of this invention. FIG. 3 is a cross-sectional view of a cylinder in which a photoelectric conversion device is installed according to an eighth embodiment of the present invention. It is a partially enlarged cross-sectional view which shows the detail of the light introduction part of the photoelectric conversion device installation cylinder shown in FIG. 35. FIG. 3 is a partially enlarged cross-sectional view showing an enlarged intermediate band type solar cell of a cylindrical photoelectric conversion device installed according to an eighth embodiment of the present invention and a waveguide core layer in the vicinity thereof. FIG. 3 is a partially enlarged side view showing an enlarged intermediate band type solar cell of a cylindrical photoelectric conversion device installed according to an eighth embodiment of the present invention and a waveguide core layer in the vicinity thereof. FIG. 3 is a partially enlarged vertical sectional view showing an enlarged intermediate band type solar cell of a cylindrical photoelectric conversion device installed according to an eighth embodiment of the present invention and a waveguide core layer in the vicinity thereof. It is a schematic diagram which shows the result (light field) of the simulation of the region shown by the alternate long and short dash line of FIG. 35 of the photoelectric conversion device of a cylindrical photoelectric conversion device installed according to the eighth embodiment of the present invention. FIG. 9 is a partially enlarged cross-sectional view showing an enlarged intermediate band type solar cell of a cylindrical photoelectric conversion device installed according to a ninth embodiment of the present invention and a waveguide core layer in the vicinity thereof. FIG. 9 is a partially enlarged side view showing an enlarged intermediate band type solar cell of a cylindrical photoelectric conversion device installed according to a ninth embodiment of the present invention and a waveguide core layer in the vicinity thereof. FIG. 9 is a partially enlarged vertical sectional view showing an enlarged intermediate band type solar cell of a cylindrical photoelectric conversion device installed according to a ninth embodiment of the present invention and a waveguide core layer in the vicinity thereof. It is a front view which shows the photoelectric conversion device installation cylinder by the tenth embodiment of this invention. FIG. 5 is an enlarged vertical sectional view of a photoelectric conversion device installed on the top of a column for installing a photoelectric conversion device according to a tenth embodiment of the present invention. It is a perspective view which shows the building which installed the photoelectric conversion device by 11th Embodiment of this invention. FIG. 3 is an enlarged cross-sectional view showing details of a photoelectric conversion device installed on an outer wall of a building in which a photoelectric conversion device is installed according to the eleventh embodiment of the present invention. It is a partial cross-sectional view of the photoelectric conversion device installation cylinder according to the twelfth embodiment of this invention. It is a schematic diagram which shows the result (optical field) of the simulation performed for verifying the waveguide performance of the optical waveguide part of the photoelectric conversion device of the photoelectric conversion device installation column according to the twelfth embodiment of the present invention. Photoelectric conversion device installation according to the twelfth embodiment of the present invention A state when the side surface of a cylindrical sample prepared for verifying the waveguide performance of the optical waveguide of a cylindrical photoelectric conversion device is irradiated with green light is shown. It is a drawing substitute photograph shown. When the columnar sample prepared for verifying the waveguide performance of the optical waveguide of the photoelectric conversion device installed in the photoelectric conversion device according to the twelfth embodiment of the present invention is curved and the side surface is irradiated with green light. It is a drawing substitute photograph showing the state of.

Hereinafter, an embodiment for carrying out the invention (hereinafter referred to as “embodiment”) will be described with reference to the drawings.

<First Embodiment>
[Photoelectric converter]
1 and 2 show a photoelectric conversion device according to the first embodiment, FIG. 1 is a cross-sectional view, and FIG. 2 is a plan view seen from the light incident surface side. As shown in FIGS. 1 and 2, this photoelectric conversion device includes an optical waveguide section 10, an intermediate band type solar cell 20 constituting the photoelectric conversion section, and light provided on the light incident surface 10a of the optical waveguide section 10. It has a traveling direction changing layer 30 (not shown in FIG. 2). The optical waveguide 10 and the intermediate band solar cell 20 are provided on the substrate 40. However, the substrate 40 can be omitted if necessary. The planar shape of the photoelectric conversion device is not particularly limited and is selected as needed, but FIG. 2 shows a case where the planar shape of the photoelectric conversion device has a rectangular shape as a typical example.

The details of the optical waveguide 10 are shown in FIG. 3 (see Patent Document 2). As shown in FIG. 3, in the optical waveguide portion 10, the upper and lower sides of the flat plate-shaped waveguide core layer 13 are sandwiched between the clad layer 11 and a plurality of clad layers 12 periodically arranged at intervals δ in the waveguide direction. Has a structure. The side surface of the semiconductor layer 21 of the intermediate band type solar cell 20 is bonded to the light emitting end surface 13a of the waveguide core layer 13. The clad layer 11 continuously covers one main surface (upper surface) of the waveguide core layer 13, and the clad layer 12 discontinuously covers the other main surface (lower surface) of the waveguide core layer 13. The clad layer 11 and the clad layer 12 together form a clad layer that discontinuously covers the waveguide core layer 13. That is, this clad layer has the end portion of the disconnection portion (for example, indicated by E in FIG. 3) that does not cover the waveguide core layer 13 and the waveguide direction of the waveguide core layer 13 with respect to the disconnection portion. The waveguide core layer 13 extends in the direction opposite to the waveguide and away from the waveguide core layer 13 (for example, indicated by P in FIG. 3) and toward the waveguide direction of the waveguide core layer 13. A part of the structure is provided so that the tangent line at the end of the break portion is parallel to or substantially parallel to the waveguide core layer 13, as will be described later. Both side surfaces of the waveguide core layer 13 may be covered with an extension portion of the clad layer 11 or may be configured with a reflective surface. The details of the coupling portion between the clad layer 12 and the waveguide core layer 13 are shown in FIG. 4, and the details of the coupling portion over a wider area are shown in FIG. In FIGS. 4 and 5, the clad layer 12 is represented by clad layers 12-a, 12-b, 12-c, and 12-d. A light introduction core layer 14 is provided between each clad layer 12 and the adjacent clad layer 12. In FIGS. 4 and 5, the light-introduced core layer 14 is represented by the light-introduced core layers 14-a, 14-b, 14-c, and 14-d. The clad layer 12 and the light introduction core layer 14 extend in the vertical direction (depth direction) of FIG. The clad layer 12 has a shape that is concavely curved in the waveguide direction of the waveguide core layer 13, and the shape is selected as necessary. In FIG. 3, the clad layer 12 has a quarter circle as an example. The case with a shape is shown. The tangent at the end of the clad layer 12 on the side of the waveguide core layer 13 coincides with the surface of the waveguide core layer 13, and thus coincides with the waveguide direction in the waveguide core layer 13. In other words, the end of the clad layer 12 on the waveguide core layer 13 side is tangentially connected to the waveguide core layer 13. The refractive index of the

clad layers

11 and 12 and the waveguide core layer 13 is clad with respect to the refractive index of the waveguide core layer 13 so that light can be confined in the waveguide core layer 11 by the

clad layers

11 and 12. The refractive indexes of the

layers

11 and 12 are selected to be small. Further, the refractive index of the clad layer 12 and the light-introduced core layer 14 is such that the light can be confined in the light-introduced core layer 14 by the clad layer 12 with respect to the refractive index of the light-introduced core layer 14. The refractive index of light is selected to be small. The refractive index of the waveguide core layer 13 and the refractive index of the light introduction core layer 14 are preferably and equally selected, but are not limited thereto. The planar shape of the optical waveguide 10 is not particularly limited and is selected as needed, but is, for example, a rectangle or a square, and FIG. 2 shows the case of a rectangle.

The clad layer 12 having the cross-sectional shape of the above-mentioned quarter circle has a light incident surface 10a (bottom surface of the optical waveguide portion 10) and has a vertical tangent line thereof. Correspondingly, at the opposite end of the quarter circle, the clad layer 12 breaks, where it has a horizontal tangent. Since the clad layer 12 is periodically arranged laterally with an interval δ, the waveguide core layer 13 (the portion having a large refractive index) is formed at the upper end of the quarter circle, as shown in FIG. It is characterized by having a geometrically open structure without being completely closed by the clad layer 12. As a result, when the x-axis is taken in the waveguide direction as shown in FIG. 3 (the z-axis is taken in the thickness direction of the optical waveguide 10 and the y-axis is taken in the direction perpendicular to the paper surface of FIG. 3), the clad layer 12 is taken. When x = x _i is described as a point where is discontinuous as shown in FIG. 4, in x <x _i , in the vicinity of the waveguide core layer 13 and its lower portion, as shown in FIG. 4, along the waveguide direction. There are four clad layers 12 (as a cross-sectional shape), that is, clad layers 12-a, 12-b, 12-c, and 12-d. That is, in the region (x ≧ x _i ) after the point where the clad layer 12-a shown in FIG. 4 is cut off, the waveguide core is from the outside world other than the starting point (in FIG. 5, from the lower left side through the light introduction core layer 14a). Light can penetrate the layer 13. As shown in FIGS. 4 and 5, at a point shifted to the right by δ (2δ) from x = x _i , that is, at x = x _i + δ (x = x _i + 2δ), the light introduction core layer 14-b ( The optical introduction core layer 14-c) (tributary) joins the waveguide core layer 13 (main stream) (in FIG. 5, for the sake of simplicity, the optical introduction core layer and the optical introduction core layer existing below the optical introduction core layer 14-c). The clad layer between the light-introduced core layer and the light-introduced core layer 14-c is not shown). As shown in FIG. 5, the tangents (indicated by the broken line in the figure) at the right end (discontinuity) of the clad layers 12-a, 12-b, and 12-c are parallel or substantially parallel to the waveguide light traveling direction. It has become. That is, a tangential connection is formed to the waveguide core layer 13 at the end of the clad layers 12-a, 12-b, and 12-c. In this way, the waveguide core layer 13 is provided with continuous translational symmetry along the traveling method as shown by the thick arrow in FIG. 5, and the clad layer 12 is provided with discrete translational symmetry having a period δ. Give sex. As a result, the waveguide core layer 13 has a quasi-open structure. The clad layer 12-a, which is in close contact with the waveguide core layer 13 at x _i -δ <x <x _i , has a discontinuous structure at the terminal portion x = x _i , but has a smooth and substantially parallel structure from below. Another clad layer 12-b under one layer approaching the waveguide core layer 13 covers the disconnection of the closest clad layer and becomes the closest clad layer by itself, so that the inside of the waveguide core layer 13 is formed. Light is efficiently guided to the right in FIG. 3 without causing loss. Further, at this time, each clad layer 12 is geometrically at the upper end portion thereof (the tangent line thereof is parallel (horizontal) or substantially parallel to the waveguide core layer 13 as shown by a broken line in FIG. 5). Parallel or substantially parallel to the upper cladding layer 11. Since the waveguide direction is parallel to the cladding layer 11 (because it is of course horizontal), the cladding layer 12 is along the waveguide direction at its rearmost end with respect to the waveguide core layer 13 as described above. , Has a structure that merges with the tangential. According to the Huygens principle, the light that has been waveguideed through the waveguide core layer 13 as a minute spherical wave tries to spread from the point where the closest clad layer 12-a is terminated at x = x _i , but the above-mentioned tangential property It is totally reflected by the clad layer 12-b, which is one step lower than the layer that comes close to the bottom. The above-mentioned "parallel or nearly parallel" is defined as being parallel to the extent that total reflection can occur by the above process. Due to this parallelism, the light in the waveguide core layer 13 is not dissipated as described above, and is guided almost 100% efficiently. At x = x _i + δ, exactly the same thing occurs for the clad layer 12-b and the clad layer 12-c. The same applies to all subsequent mainstream and tributary confluences.

The material of the waveguide core layer 13 may be, for example, an inorganic substance having a refractive index of 1.42 or more and 2.0 or less, an inorganic glass, or a refractive index of 1, depending on the materials of the clad layers 11 and 12 (including air itself). Examples thereof include, but are not limited to, a resin having a high refractive index of .55 or more. Examples of the material of the light introduction core layer 14 include, but are limited to, an inorganic substance having a refractive index of 1.48 or more and 2.0 or less, inorganic glass, or a high refractive index resin having a refractive index of 1.55 or more. (As described above, especially when an air layer or the like is used as a clad layer sandwiching the same layer). Further, examples of the

clad layers

11 and 12 include resins having a low refractive index such as 1.34, for example, CYTOP (in addition, an air layer or the like can also be used). To give an example of a combination of the refractive index of the waveguide core layer 13 and the light introduction core layer 14 and the refractive index of the cladding layers 11 and 12, the refractive index of the waveguide core layer 13 and the light introduction core layer 14 is 2.0. , The refractive index of the

clad layers

11 and 12 is 1.35. By setting the refractive index of the waveguide core layer 13 and the optical introduction core layer 14 to, for example, around 1.6, an inexpensive material can be used, so that the area of the optical waveguide can be easily increased, so that the optical waveguide can be used. When it is necessary to increase the area, it is conceivable to set the refractive index of the waveguide core layer 13 and the light introduction core layer 14 to around 1.6 and the refractive index of the

clad layers

11 and 12 to 1.35. Alternatively, the light-introduced core layer 14 is manufactured with a sacrificial spacer layer interposed therebetween, and after the light-introduced core layer 14 is completed, the sacrificial spacer layer is melted, for example, to form an air layer (refractive index = 1) as described above. ) Itself can also be used as a clad layer. In this case, the refractive index of the waveguide core layer 13 and the light introduction core layer 14 can be, for example, about n = 1.5 to 1.7, which is the refractive index of ordinary building material glass. This photoelectric conversion device can be used, for example, by laminating it on a building window material with the clad layer 11 of the optical waveguide portion 10 facing down. In this case, photovoltaic power generation can be easily realized in the building window material.

The thickness of the

clad layers

11 and 12 is, for example, 1 μm or more and several μm or less (for example, 2 μm or less), but is not limited thereto. The thickness of the waveguide core layer 13 is preferably 2 μm or more and 300 μm or less, or 2 μm or more and 300 μm or less, but the clad layer 11 is used as a coating layer (or the air layer itself) and the glass window material itself is used as a waveguide core layer. It is also possible to set it to 13. Evaluating the area S of the portion having a large refractive index in the entire waveguide structure shown in FIG. 1 and the total extension (~ total extension of the cross-sectional length of the clad layer) L of the edge curve surrounding the area, S to cL ² The reciprocal of the defined coefficient c: 1 / c = 200 to 104, which is an amount on the order of one million to ten ^thousand . Generally, the value of 1 / c is one digit or more larger than that of the conventional waveguide of the same size for the waveguide of the optical waveguide section 10. This makes it possible to introduce light from the outside world everywhere between the start point and the end point of the waveguide core layer 13, so that a region having the same refractive index as the waveguide core layer 13, that is, the light introduction core layer 14 Is continuous up to the edge of the waveguide core layer 13, and the total length (line segment of the cross section) of the clad layer 12 that exists at the edge of this region and contributes to the introduction of light from the outside is much longer. ..

The size of each part of the optical waveguide 10 is selected as needed. For example, the width in the x-axis direction of FIG. 3 is 5 cm or more and 100 cm or less, the thickness in the z-axis direction is 1 mm or more and 6 mm or less, and the depth (y-axis). The width in the direction) is 3 cm or more and 50 cm or less, and the curved shape of the clad layer 12 is a quarter circle with a radius of 6 mm.

The semiconductor layer 21 constituting the intermediate band type solar cell 20 is parallel to the extending direction of the waveguide core layer 13. Preferably, the surface of the semiconductor layer 21 facing the light emitting end surface 13a of the waveguide core layer 13 has a low surface reflectance in order to prevent reflection of the two-dimensional propagating light emitted from the light emitting end surface 13a. A functional structure, such as a moth-eye structure, is provided. By using a structure having such a surface low reflectance function, it is possible to make the reflectance of the side surface of the semiconductor layer 21 extremely small (for example, 1 to 3%). The semiconductor layer 21 has a pn junction, and the pn junction surface thereof is parallel to the main surface of the waveguide core layer 13. The semiconductor layer 21 generally has an elongated rectangular planar shape. The first electrode 22 and the second electrode 23 are provided on a pair of surfaces (upper surface and lower surface) facing each other above and below the semiconductor layer 21 (with the light incident side facing up), respectively, and ohmic contact is made with the semiconductor layer 21, respectively. is doing. One of these first electrode 22 and the second electrode 23 is used as an anode electrode, and the other is used as a cathode electrode. For example, the first electrode 22 is used as an anode electrode, and the second electrode 23 is used as a cathode electrode. The semiconductor layer 21 has a structure in which an intermediate band is formed in the band gap of the host semiconductor. FIG. 6 shows an enlarged joint portion between the optical waveguide portion 10 and the semiconductor layer 21. As shown in FIG. 6, the semiconductor layer 21 has a structure in which an intermediate band forming layer 213 is provided between the semiconductor layer 211 forming the pn junction and the semiconductor layer 212. For example, when the first electrode 22 is used as an anode electrode and the second electrode 23 is used as a cathode electrode, the semiconductor layer 211 is p-type and the semiconductor layer 212 is n-type. The intermediate band forming layer 213 is selected as needed, and is composed of, for example, a semiconductor layer having a single or single or multiple quantum well structure, a semiconductor layer having a quantum dot structure, and the like. The spread width of the intermediate band forming layer 213 along the light traveling direction is set to be at least three times or more the reciprocal of the light absorption coefficient α of the semiconductor constituting the intermediate band forming layer 213. By doing so, it is possible to maximize the light absorption by the intermediate band forming layer 213.

In this photoelectric conversion device, incident light (three-dimensional space propagating light) incident from the outside on the light traveling direction conversion layer 30 provided on the light incident surface of the optical waveguide section 10 is guided through the light introduction core layer 14. After entering the inside of the wave core layer 13 and being waveguideed as two-dimensional space propagating light, it is emitted from the light emitting end surface 13a of the waveguide core layer 13 and is incident on the entire side surface of the semiconductor layer 21 of the intermediate band type solar cell 20. It is configured to do. Since the two-dimensional space propagating light emitted from the light emitting end surface 13a of the waveguide core layer 13 is incident on the entire side surface of the semiconductor layer 21, the photocarrier is photo-excited through the band gap of the host semiconductor of the semiconductor layer 21. Is generated, and photocarriers are generated by photoexcitation via the intermediate band. In this case, the photocarrier generated in the semiconductor layer 21 by the net traveling direction of the light waved inside the waveguide core layer 13 and the light incident on the semiconductor layer 21 from the end face of the waveguide core layer 13. The angle Θ formed with the net traveling direction (moving direction) (direction connecting the first electrode 22 and the second electrode 23 at the shortest distance) is approximately a right angle. The area (area of the light receiving portion) S of the light incident surface of the optical waveguide portion 10 is such that the length of the light incident surface is L and the width is W (see FIG. 2).
S = L × W (1)
The area s of the side surface of the semiconductor layer 21 is given by, assuming that the thickness of the semiconductor layer 21 is d.
s = L × d (2)
Since it is given by, the light collection ratio R is R = S / s = W / d ~ (10 cm ~ 100 cm) / 100 μm = 1000 ~ 10000.
(3)
Is easily obtained. According to Non-Patent Document 7, under such high-magnification focusing, the quasi-Fermi level is sufficiently separated by the photofilling of the intermediate band, and it is suggested that the voltage is maintained. Including the temperature, this photoelectric conversion device will be the first concrete and practical photoelectric conversion system capable of fully functioning the intermediate band type solar cell 20.

In this photoelectric conversion device, preferably, when light is incident from the outside, the light is not directly incident on the semiconductor layer 21. In other words, when light is incident on the photoelectric conversion device, the light is incident on the light traveling direction conversion layer 30 provided on the light incident surface of the optical waveguide section 10, but the light is directly incident on the surface of the semiconductor layer 21. Try not to. For this purpose, specifically, for example, the following is performed. For example, a light-shielding layer is provided above the semiconductor layer 21 so as to cover the first electrode 22. A conventionally known light-shielding layer can be used and is selected as needed. For example, an aluminum laminated film having a plastic film formed on both sides of an aluminum foil is used. With this light-shielding layer, it is possible to prevent light from directly incident on the semiconductor layer 21. Further, when the substrate 40 constitutes a part of the outer surface of a building or an electronic device, sunlight is incident on the light traveling direction conversion layer 30, but sunlight is not incident on the semiconductor layer 21. In other words, the semiconductor layer 21 is covered with a member or the like so as to be in the shadow. For example, when this photoelectric conversion device is installed in a window of a building, the window glass becomes a substrate 40, and an optical traveling direction conversion layer 30 and an optical waveguide portion 10 are provided on the window glass exposed to the outside, and a semiconductor layer is provided. 21 is hidden inside a window frame made of Al, for example. Further, when this photoelectric conversion device is laid on the roof of a building, the ends of adjacent photoelectric conversion devices are overlapped vertically, and the semiconductor layer 21 at the end of the upper photoelectric conversion device is used to make the lower photoelectric conversion device. The semiconductor layer 21 at the end of the is covered. Further, when the photoelectric conversion device is installed in the display unit of an electronic device, for example, a smartphone, the transparent member on the surface of the display unit becomes the substrate 40, and the light traveling direction conversion layer 30 and the light traveling direction conversion layer 30 are placed on the transparent member exposed to the outside. An optical waveguide 10 is provided, and the semiconductor layer 21 is hidden inside a member provided on the surface of the display.

The semiconductor layer 21 is selected as needed from, for example, those already listed. The semiconductor layer 21 is typically a pn junction composed of a p-type semiconductor layer and an n-type semiconductor layer, and has a structure forming an intermediate band, for example, a quantum dot layer. The first electrode 22 and the second electrode 23 are in ohmic contact with the semiconductor layer 21. The length of one side of the semiconductor layer 21 is typically chosen to be the same as the length of the side of the waveguide core layer 13 on which the semiconductor layer 21 is provided, but the length of the side perpendicular to this side is typical. It is 0.5 μm to 5 mm, preferably 2 μm to 1 mm. Since the size of the optical waveguide 10 is, for example, (5 cm to 100 cm) × (3 cm to 50 cm) as described above, the area of the semiconductor layer 21 is generally much smaller than the area of the optical waveguide 10. I'm done. That is, in this photoelectric conversion device, the optical waveguide portion 10 occupies a large part, and the semiconductor layer 21 occupies only a small part at the end. For example, assuming that the size of the optical waveguide 10 is 10 cm × 10 cm and the size of the semiconductor layer 21 is 1 mm × 10 cm, the ratio of the area of the semiconductor layer 21 to the total area of the optical waveguide 10 and the semiconductor layer 21 is , 0.1 × 10 / 10.1 × 10 = 0.0099 ≈ 1%. In addition to this, since the thickness of the semiconductor layer 21 is generally as small as several tens of μm or less, the volume of the semiconductor layer 21 is also extremely small. That is, the amount of the semiconductor layer 21 used can be extremely small. Therefore, it is possible to reduce the manufacturing cost of the photoelectric conversion device.

The band gap or HOMO-LUMO gap _Eg of the host semiconductor or the intermediate band of the semiconductor layer 21 may be uniform along the traveling direction of the photoelectric conversion light, that is, the light waveguideed in the semiconductor layer 21, but is further photoelectric. In order to increase the conversion efficiency, a measure is taken to reduce the light discretely and stepwise in N steps (N ≧ 2) along the traveling direction of the light in the semiconductor layer 21, or to reduce the light continuously (continuously). Please refer to FIG. 8 below for the case of the reduction.) For example, the host semiconductor of the semiconductor layer 21 is composed of the same semiconductor, and E _g in the intermediate band is gradually reduced in N steps (N ≧ 2) in the traveling direction of light in the semiconductor layer 21, or continuously. It is reduced, or E _g of the host semiconductor and the intermediate band of the semiconductor layer 21 is gradually reduced in N steps (N ≧ 2) in the traveling direction of light in the semiconductor layer 21, or is continuously reduced. In the latter case, the intermediate band forming layer 213 of the semiconductor layer 21 forms an intermediate band in each band gap. When E _g is gradually reduced in N steps in the traveling direction of light, E _g1 , E _g2 , ..., E _gN (E _g1 > E _g2 >...> E _gN ) are used in this order. FIG. 7 shows the case of N = 4 as an example. As shown in FIG. 7, the semiconductor layer 21 includes

regions

21a, 21b, 21c, and 21d in which E _g is composed of host semiconductors of E _g1 , E _g2 , E _g3 , and E _g4 , respectively. Each

region

21a, 21b, 21c, 21d has an elongated striped shape extending in a direction parallel to the side of the waveguide core layer 13 provided with the semiconductor layer 21. The width of each E _gi region constituting the semiconductor layer 21 (the width in the traveling direction of light, the length in the lateral direction in FIG. 7) is the photoelectric conversion target photon of each E _gi region (band gap E of each E _gi region). If the absorption coefficient of this E _gi region for the photon with the lowest energy among the photons having energy of _gi or more is α _i , it is 1 / α _i or more.

E _gi can be set as follows. For example, in the entire wavelength range of the AM1.5 solar spectrum or its main wavelength range (the range including the portion having high incident energy), the wavelength is divided into N sections. Then, these sections are numbered in order from the short wavelength side (high energy side) such as 1, 2, ..., N, and E _gi is selected equal to the minimum photon energy of the i-th section. By doing so, when a photon having photon energy in the kth section is incident on the _Egi region, an electron-hole pair is generated and photoelectric conversion is performed. Further, in this case, the E _gi is obtained from the junction surface between the waveguide core layer 13 and the semiconductor layer 21 so that the photons having the photon energy in the kth section reach each E _gi region and are sufficiently absorbed. Choose the distance to the area. As a result, the sunlight that is waveguideed inside the waveguide core layer 13 and enters the semiconductor layer 21 first enters the E _g1 region, and the photon energy of E _g1 or higher in the spectrum is absorbed, and further. By excitation via the intermediate band, those with smaller photon energies are also absorbed and photoelectrically converted, and then incident on the E _g2 region, and the photon energy of E _g2 or more and smaller than E _g1 in the spectrum is absorbed. Furthermore, those with smaller photon energies are also absorbed and photoelectrically converted by excitation via the intermediate band, and finally enter the E _gN region, and the photon energy of the spectrum is E _gN or more and smaller than E _gN-1 . Is absorbed, and even smaller photon energies are absorbed and photoelectrically converted by excitation via the intermediate band. As a result, light in almost the entire range of the solar spectrum or in the main wavelength range can be used for photoelectric conversion.

Each E _gi can be set by changing the composition of the host semiconductor constituting each E _gi region, the form of the semiconductor (amorphous, polycrystal, single crystal), the intermediate band forming layer 213, or the like. Specifically, for example, the host semiconductor constituting each _Egi region is configured by another type of semiconductor. In this case, the semiconductor has a wide range of choices because a semiconductor having a high carrier mobility μ can be selected regardless of the magnitude of the absorption coefficient α. Some specific examples of the case of using an inorganic semiconductor are as follows. In the case of N = 3, for example, the E _g1 region is Si _x C _1-x (E _g = 1.8 to 2.9 eV), the E _g2 region is Si (E _g = 1.11 eV), and the E _g3 region. Is composed of Ge (E _g = 0.76 eV). When N = 4, for example, the E _g1 region is Si _x C _1-x (E _g = 1.8 to 2.9 eV), and the E _g2 region is amorphous silicon (a-Si) (E _g =). 1.4 to 1.8 eV), the E _g3 region is composed of Silicon Ge _1-y ₍ E _g = 1.11 eV), and the E _g4 region is composed of Silicon Ge _1-y ₍ E _g = ~ 0.76 eV). .. Alternatively, when N = 4, the E _g1 region is IGZO (oxide of In, Ga, Zn) (E _g = ~ 3 eV), and the E _g2 region is Si _x C _1-x (E _g = ~ 1.8 eV). ), The E _g3 region is composed of Si (E _g = 1.11 eV), and the E _g4 region is composed of Si _y Ge _1-y (E _g = ~ 0.76 eV). In addition, it can be configured as follows. In the simplest case of N = 2, for example, the E _g1 region is a-Si (E _g = 1.4 to 1.8 eV), and the E _g2 region is Si _y Ge _1-y (E _g = to 0. 76eV). When N = 3, for example, the E _g1 region is GaP (E _g = 2.25 eV), the E _g2 region is GaAs (E _g = 1.43 eV), and the E _g3 region is InN (E _g = 0). It is composed of .7eV). When N = 4, for example, the E _g1 region is Ga _x In _1-x N (E _g = 2.3 eV), and the E _g2 region is Gay In _1-y _N (E _g = 1.4). ~ 1.8 eV), the E _g3 region is composed of Gaz In _1-z _N (E _g = 1.1 eV), and the E _g4 region is composed of In N (E _g = 0.7 eV). When N = 5, for example, the E _g1 region is CdSe fine particles having a diameter of about 1.9 nm (absorption peak wavelength 445 nm), and the E _g2 region is CdSe fine particles having a diameter of about 4.0 nm (absorption peak wavelength 585 nm). The E _g3 region is PbSe fine particles with a diameter of about 2 nm (absorption peak wavelength 800 nm), the E _g4 region is PbSe fine particles with a diameter of about 4.5 nm (absorption peak wavelength 1100 nm), and the E _g5 region is PbSe fine particles with a diameter of about 90 nm (absorption peak wavelength). 2300 nm). Further, it is also possible to construct an _Egi region in the case of N to 10 only by controlling x using GaInN _x As _1-x or GaInN _x P _1-x . In addition, the E _gi region may be constructed using a II-VI group compound semiconductor, which is known to exhibit large bowing when Te is included. Specific examples of the case where an organic semiconductor and an inorganic semiconductor are used are as follows. For example, when N = 4, the E _g1 region is MDMO-PPV (E _g = 2.2 eV), the E _g2 region is a-Si (E _g = 1.4 to 1.8 eV), and the E _g3 region is used. A polyacene-based (hexacene) semiconductor (E _g = 1 to 1.2 eV) and an E _g4 region are composed of a polyacene-based (heptacene) semiconductor (E _g = 0.6 to 08 eV). Further, when N ≧ 2, the E _g1 region is IGZO (oxide of In, Ga, Zn) (E _g = ~ 3eV), AlInN (E _g = 2.8 to 3eV), or GaInN (E _g =). 2.8 to 3 eV) or one of oxide semiconductors (ZnO, ZnMgO, etc.) having a similar bandgap, and the region following it, for example, the E _g2 region is a-Si (E _g = 1). By setting it to .4 to 1.8 eV), photons that cause the Stebler-Lonsky reaction, which has been shown to be generated by light having a wavelength of 450 nm or less, are photoelectrically converted before entering the a—Si layer in advance. By keeping the reaction, the reaction can be suppressed, and therefore the life of the photoelectric conversion region made of the a—Si layer can be extended. It is also effective to use a halide-based organic-inorganic perovskite semiconductor (CH ₃ NH ₃ PbI ₃ ) solar cell or CZTS made of copper, zinc, tin, or sulfur as raw materials at the end of the waveguide core layer 13. A CIGS (Cu, In, Ga, Se) system or a CZTSe (Cu ₂ ZnSnSe ₄ ) system may be used. Since bulk recombination in the CZTS is considered to be a factor of performance deterioration, the arrangement in which the light traveling direction and the photocarrier traveling direction are orthogonal to each other as shown in FIG. 6 allows the time for the photocarrier to arrive at the electrode to absorb light. It is extremely effective because it can be shortened without sacrifice. On the other hand, CTGS containing copper, tin, germanium, and sulfur as constituent elements has a bandgap of 1.0 eV, has a high light absorption coefficient, and is attracting attention as a material for non-toxic and non-rare elements. The band gap can be adjusted by controlling the Ge / Sn ratio.

The thickness d of each E _gi region is selected as needed, and is, for example, several μm to several tens of μm. The width of each E _gi region (width in the traveling direction of light in the semiconductor layer 21) is also selected as needed, and is, for example, several tens of μm to several hundreds of μm. For example, the thickness _d of each

region

21a, 21b, 21c, 21d is several μm to several tens of μm, and the widths w1 to w4 of _each

region

21a, 21b, 21c, 21d are several tens μm to several hundred μm, for example. Select 100 μm.

FIG. 8 shows an example of a case where the band gap or HOMO- _LUMO gap Eg of the host semiconductor or the intermediate band of the semiconductor layer 21 is continuously reduced in the traveling direction of light in the semiconductor layer 21. In FIG. 8, E _c and E _v are the energy at the lower end of the conduction band and the upper end energy of the valence band of the host semiconductor, respectively, and E _cIB and E _vIB are the energy and the valence band at the lower end of the conduction band of the intermediate band, respectively. Indicates the energy at the top. As shown in FIG. 8, the same semiconductor is used as the host semiconductor of the semiconductor layer 21, and an inclined composition quantum well layer whose composition is gradually inclined in the traveling direction of light in the semiconductor layer 21 is used as the intermediate band forming layer 213. Thereby, the band gap of the intermediate band can be gradually reduced in the traveling direction of the light. As the quantum well layer having such an inclined composition, specifically, for example, a GaInN layer having an inclined In composition can be used. FIG. 9 is an insertion view after the GaInN layer is epitaxially grown on a 3-inch sapphire substrate by the MOCVD method after having the temperature distribution of the substrate in the lateral direction so that the temperature decreases as the distance from the center of the substrate decreases. The results of measuring the photoluminescence spectrum of the GaInN layer at

points

0, 1, 2, 3, 4, and 5 in the radial direction shown in (1) are shown. FIG. 10 is a plot of the radial bandgap of the GaInN layer relative to the position from the center of the substrate from the results of the photoluminescence spectrum. As shown in FIG. 10, the band gap linearly decreases as the position from the center of the substrate increases. It can be seen that the bandgap of the GaInN layer is controlled over a distance of 10 mm over about 1 eV. This means that the In composition of the GaInN layer increases as the position from the center of the substrate increases, but the rate of In uptake into the growth layer corresponding to the temperature distribution of the substrate is the center of the substrate. This is the result of the increase as the position from is increased. As described above, a structure in which the bandgap is inclined in the lateral direction can be easily formed by one-time epitaxial growth. Further, as is clear from the above results, it has been demonstrated that when GaN is used as the host semiconductor of the semiconductor layer 21, the GaInN layer can be formed as the intermediate band forming layer 213 in the GaN.

The substrate 40 can also play a role of mechanical support and mechanical protection of the optical waveguide portion 10 and the intermediate band type solar cell 20, and serves as a clad layer for efficiently confining light inside the waveguide core layer 13. In this case, the clad layer 11 can also be used. The substrate 40 is, for example, a glass plate, a transparent plastic plate, or the like. Examples of the transparent plastic constituting the transparent plastic plate include polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polystyrene, polyethylene, polypropylene, polyphenylene sulfide, polyvinylidene fluoride, acetylcellulose, brominated phenoxy, aramids, polyimides, and polystyrene. Classes, polyarylates, polysulfones, polyolefins and the like can be used. Further, the substrate 40 may be flexible, and in this case, the photoelectric conversion device can be easily installed in a state of being bent along a convex or concave surface. The substrate 40 preferably has a sufficiently low refractive index as compared with the waveguide core layer 13 so that the substrate 40 can serve as a clad layer for efficiently confining light inside the waveguide core layer 13. Formed by the material. Further, the substrate 40 may have a multi-layer structure of two or more layers. In this case, the refractive index of the layer of the substrate 40 in contact with the waveguide core layer 13 must satisfy the above conditions and have a required thickness (typically 0.1 μm to several μm). As long as the conditions are satisfied, the physical property values of the remaining layers can be freely selected (for example, substances having light absorption are also acceptable).

11, 12 and 13 show the details of the light traveling direction conversion layer 30, FIG. 11 is a cross-sectional view, and FIGS. 12 and 13 are plan views (bottom views) seen from the light incident surface side. Here, FIG. 12 is an arrangement example in which the arrangement of the rotating release object-shaped portion 32 and the hemispherical portion 33, which will be described later, has a four-fold symmetry, and FIG. 13 is an arrangement example in which the arrangement has the same six-fold symmetry. FIG. 11 is a cross-sectional view taken along the alternate long and short dash line of FIGS. 12 and 13. The light traveling direction changing layer 30 makes the incident light travel in a direction perpendicular to the light incident surface of the light traveling direction changing layer 30 regardless of the incident angle of the incident light incident on the light traveling direction changing layer 30. It is for conversion. As shown in FIGS. 11 and 12 or 13, a large number of optical traveling direction conversion layers 30 are provided vertically and horizontally in a two-dimensional array on one main surface of a flat plate-shaped transparent base material 31 and the transparent base material 31. It has a transparent rotating release object-shaped portion 32, and a transparent hemispherical portion 33 having a surface made of a hemisphere and provided so as to cover these rotating release object-shaped portions 32. The hemispherical portion 33 acts as a hemispherical lens. The focal point of the rotating release object-shaped portion 32 and the center of the hemispherical portion 33 covering the rotating release object-shaped portion 32 coincide with each other. The curvature of the surface of the tip of the rotating object-shaped portion 32 is larger than the curvature of the hemisphere of the hemispherical portion 33, and is sharp. The distance a between the focal point F and the tip of the rotating object-shaped portion 32 and the width D of the rotating object-shaped portion 32 are selected as necessary, but L is 0.5 μm or more and 0.8 μm or less, for example, 0. 625 μm and W are 1.5 μm or more and 2.5 μm or less. The radius of the hemispherical portion 33 is W / 2. The refractive index of the air outside the light traveling direction conversion layer 30 is n ₁ , the refractive index of the hemispherical portion 33 is n ₂ , the rotating object-shaped portion 32 excluding the overlapping portion with the hemispherical portion 33, and the transparent substrate. Assuming that the refractive index of 31 is n ₃ , n ₃ > n ₂ > n ₁ is established. Typically, n ₁ = 1.0, n ₂ = 1.35 to 1.5 (for example, 1.35), and n ₃ = 1.9 to 2.1 (for example, 2.0). In this case, light incident on the light incident surface of the light traveling direction conversion layer 30 at an incident angle of 0 to 80 degrees is incident on the hemispherical portion 33, travels straight inside the hemispherical portion 33, and is therefore the center of the hemispherical portion 33. The height (length) or a of the rotating release object-shaped portion 32 so as to be incident on the focal point F of the rotating release object-shaped portion 32 and to intersect the rotating release surface of the rotating release object-shaped portion 32 after passing through the focal point F. Is set. The light incident on the focal point F of the rotating object-shaped portion 32 thus travels parallel to the axis of the rotating project-shaped portion 32, and thus travels in a direction perpendicular to the light incident surface of the light traveling direction conversion layer 30. That is, even if the incident light is incident on the light incident surface of the light traveling direction conversion layer 30 from various directions, the traveling direction of the light is converted to the direction perpendicular to the light incident surface, and as a result, the light is introduced. Light can be introduced into the waveguide core layer 13 while repeating total reflection in the core layer 14. As can be seen from the above, according to the light traveling direction changing layer 30, the traveling direction of the incident light is changed with respect to the angle of sunlight from morning to evening, and the light traveling direction changing layer 30 is used. It is possible to make the light incident substantially perpendicular to the light incident surface of the optical waveguide portion 10 behind.

A simulation was performed to verify the effect of the light traveling direction changing layer 30. It is assumed that n ₁ = 1.0, n ₂ = 1.35, and n ₃ = 2.0 of the optical traveling direction conversion layer 30, and the distance D between the focal point F and the tip of the rotating object-shaped portion 32 is 0.625 μm. , W was set to 4 μm, and the radius of the hemispherical portion 33 was set to 2 μm. 14 and 15 show the results of simulation when light is incident on the light traveling direction changing layer 30 at incident angles of 40 degrees and 20 degrees, respectively. 14 and 15 show the X-axis in the direction parallel to the plane of the optical traveling direction conversion layer 30, the Z-axis in the thickness direction of the optical traveling direction conversion layer 30, and the Y-axis in the directions perpendicular to these X-axis and Z-axis. The distribution of the magnitude (intensity) of the amplitude E _y in the Y-axis direction of the electric field of the light wave in the XZ plane is shown. From FIGS. 14 and 15, the light obliquely incident on the light traveling direction changing layer 30 passes through the light traveling direction changing layer 30 and then emits in a direction substantially perpendicular to the light traveling direction changing layer 30. You can see that it does. That is, it can be seen that the light traveling direction conversion layer 30 can convert the traveling direction of the obliquely incident light into a direction substantially perpendicular to the surface of the light traveling direction conversion layer 30. In particular, from FIG. 14, which shows the case of an incident angle of 40 degrees, even for light having an intermediate incident angle (30 to 50 degrees), which was difficult in the conventional example, the light traveling direction conversion layer 30 effectively changes the traveling direction. It was shown that light could be incident substantially perpendicular to the surface of the waveguide core layer 13 (flat waveguide (two-dimensional waveguide)) behind the light traveling direction conversion layer 30.

[Operation of photoelectric conversion device]
The operation of this photoelectric conversion device will be described. As shown in FIG. 1, three-dimensional space propagating light, for example, sunlight is incident on the light incident surface of the optical traveling direction conversion layer 30 of the optical waveguide section 10 of this photoelectric conversion device. As shown in the lower part of FIG. 1, sunlight is incident on the light incident surface of the light traveling direction conversion layer 30 from an oblique direction depending on the time, but especially in the 6-fold symmetrical arrangement example shown in FIG. 13, this oblique direction. It is effective to take the plane projection of the vector so that it is parallel to the direction of the broken line shown in FIG. At this time, mutual obstruction between the hemispherical portions 33 shown in FIG. 11 can be minimized. That is, the hemispherical portion 33 shown by A in FIG. 13 is minimized to be obstructed by the hemispherical portion 33 shown by B and C, and the solid angle Ω of the sun with respect to the hemispherical portion 33 shown by A is maximized. Become. Light does not directly enter the main surface of the semiconductor layer 21 of the intermediate band type solar cell 20. The three-dimensional space propagating light incident on the light incident surface of the light traveling direction conversion layer 30 is converted in the traveling direction in the direction perpendicular to the light incident surface, and then passes through the light introduction core layer 14 to the waveguide core. It enters the inside of the layer 13, is efficiently waveguideed inside the waveguide core layer 13, exits from the light emitting end surface 13a of the waveguide core layer 13, is incident on the side surface of the semiconductor layer 21, and then advances in the semiconductor layer 21. In the process, electron-hole pairs are generated in the semiconductor layer 21. Then, the electrons and holes thus generated move in the semiconductor layer 21 by drift or diffusion, and are collected on one and the other of the first electrode 22 and the second electrode 23. In this way, photoelectric conversion is performed in the semiconductor layer 21, and a current (photocurrent) is taken out from the first electrode 22 and the second electrode 23 to the outside.

In this photoelectric conversion device, since Θ is almost a right angle as described above, unlike a conventional general solar cell, the number of absorbed photons and the photocarrier acquisition efficiency are not in a trade-off relationship. Most preferably, Θ = 90 ° can be set. In other words, the inside of the waveguide core layer 13 is waveguideed from the direction perpendicular to the straight line connecting the first electrode 22 and the second electrode 23 at the shortest, and the light is emitted from the light emitting end surface 13a of the waveguide core layer 13. The light emitted can be incident on the side surface of the semiconductor layer 21. In this case, the number of absorbed photons of the semiconductor layer 21 is the width in the incident direction of light (for example, when the semiconductor layer 21 is composed of the

regions

21a, 21b, 21c, 21d, the widths w ₁ to the

regions

21a, 21b, 21c, 21d). It is dominated by w ₄ ), and the photoelectric conversion efficiency is not dominated by the thickness d of the semiconductor layer 21 in the light absorption rate-determining region. That is, the extremely advantageous point of this photoelectric conversion device is the optimization of light absorption and the optimization of carrier collection efficiency by, for example, making the waveguide direction inside the waveguide core layer 13 and the carrier moving direction orthogonal to each other. It is possible to completely achieve both. Further, the small absorption coefficient α of the semiconductor layer 21 is the width of the semiconductor layer 21 in the incident direction of light (when the semiconductor layer 21 is composed of, for example, the

regions

21a, 21b, 21c, 21d, the region regions 21a, 21b, 21c. , 21d can be compensated by increasing the widths _w1 to _w4 ). Therefore, as the material of the semiconductor layer 21, it is possible to use a material having a large μ, which is the only dominant parameter, regardless of the size of α. can. By doing so, it becomes possible to obtain a high photoelectric conversion efficiency, and it is also possible to obtain a photoelectric conversion efficiency approaching the thermodynamic limit.

According to this first embodiment, various advantages such as the following can be obtained. That is, in this photoelectric conversion device, a three-dimensional space having a wide wavelength band that includes morning and evening sunlight or diffused light in rainy or cloudy weather and is incident on the light incident surface of the light traveling direction conversion layer 30 from various directions. The traveling direction of the propagating light is converted to a direction perpendicular to the light incident surface and incident on the optical waveguide section 10, and the inside of the waveguide core layer 13 is efficiently waveguideed to obtain two-dimensional space propagating light. Since the two-dimensional space propagating light in a wide wavelength band can be incident on the semiconductor layer 21 to perform photoelectric conversion, extremely high photoelectric conversion efficiency can be obtained. Further, since the photoelectric conversion unit is composed of the intermediate band type solar cell 20 and has an intermediate band in the band gap of the host semiconductor, the absorption wavelength band can be widened, so that it has a wide spectrum like a solar spectrum. The light from the light source can be converted into electrical energy very efficiently. Further, in this photoelectric conversion device, the optical waveguide portion 10 and the optical traveling direction conversion layer 30 occupy most of the area, and the incident light can be received by the entire light incident surface of the optical traveling direction conversion layer 30. , There is virtually no insensitive area to incident light. Further, in the conventional solar cell, since it is necessary to provide a semiconductor for photoelectric conversion on the entire light incident surface, the amount of semiconductor used is large, whereas in this photoelectric conversion device, the semiconductor layer 21 is only a part. Since it occupies only the area of the semiconductor and its volume is extremely small, the amount of semiconductor used can be small and the manufacturing cost can be reduced. Further, when the semiconductor layer 21 is composed of a plurality of regions in which the band gap or the HOMO-LUMO gap gradually decreases in the traveling direction of light in the semiconductor layer 21, the high-energy ultraviolet component of sunlight is formed. For example, can be absorbed in the region of the first stage, so that the ultraviolet component can be prevented from incident on the region of the latter stage. Therefore, even if the latter region is made of amorphous silicon or an organic semiconductor, there is no problem of the Stebler-Wronskian effect or deterioration of the organic semiconductor. Therefore, it is possible to improve the photoelectric conversion efficiency and the reliability of the photoelectric conversion device. Further, this photoelectric conversion device can easily increase the area simply by increasing the area of the optical waveguide section 10. Further, the semiconductor layer 21 is provided on the light emitting end surface 13a of the waveguide core layer 13, and the light waveguideed in the waveguide core layer 13 is emitted from the light emitting end surface 13a of the waveguide core layer 13 to form the semiconductor layer 21. Since it is configured to be incident on the side surface, it does not require a lens for condensing light, it is extremely simple to configure, and it does not require optical axis alignment, so it is not only easy to manufacture. It is also possible to reduce the manufacturing cost and prevent aging and aging. Further, in this photoelectric conversion device, the light receiving unit and the intermediate band type solar cell 20 which is the photoelectric conversion unit are separated from each other, and the space between them is not three-dimensional but two-dimensional by the waveguide core layer 13. By connecting to, it is possible to install this photoelectric conversion device not only on moving objects such as automobiles but also on all sides of buildings in the metropolitan area, for example, without spoiling the landscape. Problems such as lack of business land required for installation can be easily solved.

<Second embodiment>
[Photoelectric converter]
FIG. 16 is a cross-sectional view showing a photoelectric conversion device according to the second embodiment. The plan view (bottom view) of this photoelectric conversion device as seen from the light incident surface side is, for example, the same as in FIG. This photoelectric conversion device differs from the photoelectric conversion device according to the first embodiment in the configuration of the optical waveguide section 10. FIG. 17 shows the optical waveguide section 10 in this photoelectric conversion device. Further, FIG. 18 shows an enlarged part of the optical waveguide section 10. As shown in FIGS. 16 to 18, in the optical waveguide section 10, the cross-sectional shapes of the clad layer 12 and the optical introduction core layer 14 are different from those of the photoelectric conversion device according to the first embodiment. Specifically, in the optical waveguide portion 10, the cross-sectional shape of the clad layer 12 is continuously connected to the first arc-shaped portion 121 on the light incident surface side and the first arc-shaped portion 121. It is composed of an arc-shaped portion 122 of. The end of the second arc-shaped portion 122 on the waveguide core layer 13 side is tangentially connected to the waveguide core layer 13. The cross-sectional shape of the clad layer 12 including the first arc-shaped portion 121 and the second arc-shaped portion 122 will be described in detail with reference to FIG. FIG. 19 shows the shape of the center line (indicated by a thick solid line) of the clad layer 12 including the first arc-shaped portion 121 and the second arc-shaped portion 122. As shown in FIG. 19, the first arcuate portion 121 corresponds to a quarter portion of a vertically elongated ellipse in the waveguide core layer 13 having a short axis in the waveguide direction and a long axis in the direction perpendicular to the waveguide direction. Has a shape to be The second arc-shaped portion 122 is defined from the intersection of a quarter portion of a horizontally long ellipse having a long axis in the waveguide direction and a short axis in the direction perpendicular to the waveguide direction in the waveguide core layer 13 with the long axis. It has a shape in which a length portion is cut off, and the end point of the cut portion coincides with the intersection with the long axis of the first arcuate portion 121. The semimajor axis of the vertically elongated ellipse (1/2 of the length of the major axis) is about 6 to 100 μm, and the semimajor axis of the horizontally elongated ellipse is about 100 to 500 μm. In the example shown in FIGS. 16 to 18, the short radius (1/2 of the length of the short axis) of the vertically long ellipse is 18 μm, the long radius is 36 μm, the short radius of the horizontally long ellipse is 30 μm, and the long radius is 180 μm. In this case, when the x-axis is taken in the waveguide direction in the waveguide core layer 13, the width of the clad layer 12 in the x-axis direction is 18 μm in the vertically elongated elliptical portion and 122 μm in the horizontally elongated elliptical portion. 18 + 122 = 140 μm. As shown in FIGS. 16 to 18, in the clad layer 12, a relatively thick clad layer 12 is repeatedly present with a period Δ larger than the period δ in the x direction (horizontal direction) of the clad layer 12. The z-direction (longitudinal) distance between the relatively thick clad layers 12 at their endpoints, that is, the z-direction opening width at the point of connection to the waveguide core layer 13, which is the main two-dimensional waveguide. Typically, it is 1.8 to 6.8 μm, preferably about 3.4 μm. δ is typically 1.1 to 4.5 μm, preferably about 2.3 μm. In this case, the width of the relatively thick clad layer 12 is, for example, 1 to 2 μm, and the width of the relatively thin clad layer 12 is on the order of the wavelength of the incident light in consideration of light penetration, typically 0.4. It is about 1 μm. Assuming that the relatively thin clad layer 12 and the adjacent light introduction core layer 14 are one unit, the number of units included in the period Δ of the relatively thick clad layer 12 is determined by Δ / δ. In the examples shown in FIGS. 16 to 18, Δ = 85 μm, the number of units is 32, and δ = 2.66 μm. In this case, assuming that the width of the relatively thin clad layer 12 is 0.4 μm, the width of the light introduction core layer 14 is 2.66-0.4 = 2.26 μm. Depending on the structure of the vertically elongated ellipse and the horizontally elongated ellipse (or a circle having a relatively large radius), Δ can be about 100 μm to a maximum of about 1000 μm.

A simulation of light propagation in this photoelectric conversion device was performed. The simulation results are shown in FIGS. 20 and 21. FIG. 20 shows the whole image of the light field, and FIG. 21 shows the conversion efficiency of the three-dimensional propagating light into the two-dimensional propagating light. 66.5% by tangentially coupling to the optical waveguide core layer 13 by the contribution of the small (large radius of curvature) end of the second arcuate part 122 of the quadrant of the oblong ellipse of the clad layer 12. We were able to achieve a high conversion efficiency of 3D propagating light → 2D propagating light. Further, the relatively thick clad layer 12 supports the long-distance propagation of the waveguide light in the optical waveguide core layer 13, while the relatively thin clad layer 12 is the light introduction core of sunlight going upward from the lower part of FIG. It enables smooth propagation from the vertically elongated ellipse portion of the layer 14 to the horizontally elongated elliptical portion. Since the relatively thin clad layer 12 becomes extremely thin in the horizontally elongated elliptical portion, the role of the effective waveguide clad layer is played by the relatively thick clad layer 12. By coupling the first arcuate portion 121 and the second arcuate portion 122, the three-dimensional propagating light can be converted into two-dimensional waveguide light while reducing the loss.

Other than the above, this photoelectric conversion device is the same as the photoelectric conversion device according to the first embodiment.

According to this second embodiment, the same advantages as those of the first embodiment can be obtained.

<Third embodiment>
[Photoelectric converter]
FIG. 22 is a cross-sectional view showing a photoelectric conversion device according to the third embodiment. The plan view (bottom view) of this photoelectric conversion device as seen from the light incident surface side is, for example, the same as in FIG. This photoelectric conversion device differs from the photoelectric conversion device according to the first and second embodiments in the configuration of the optical waveguide section 10. FIG. 23 shows the optical waveguide section 10 in this photoelectric conversion device. Further, FIG. 24 shows an enlarged part of the optical waveguide section 10. As shown in FIGS. 22 to 24, in the optical waveguide section 10, the oblong elliptical portion of the clad layer 12 and the optical introduction core layer 14 of the optical waveguide section 10 of the photoelectric conversion device according to the second embodiment is formed. It is different from the photoelectric conversion device according to the second embodiment that the occupied portion is composed of the refractive index anisotropic layer 50. However, only the relatively thick clad layer 12 of the optical waveguide portion 10 of the photoelectric conversion device according to the second embodiment is provided so as to intersect with the refractive index anisotropy layer 50. The refractive index anisotropic layer 50 plays a role similar to that of the horizontally elongated elliptical portion of the clad layer 12 and the light introduction core layer 14. That is, the light emitted from the end of the first arcuate portion 121 of the clad layer 12 and the optical introduction core layer 14 of the optical waveguide portion 10 follows the same path as the second arcuate portion 122, and the waveguide core layer 13 It is configured to be tangentially incident. The refractive index anisotropy layer 50 can be composed of, for example, a liquid crystal layer of N layers (N is an integer of N ≧ 1) controlled so that the orientation of the director changes stepwise. In FIGS. 22 to 24, as an example, 10 liquid crystal layers 501 to 510 when N = 10 are shown.

A simulation of light propagation in this photoelectric conversion device was performed. As the refractive index anisotropy layer 50, the directors of the 10 liquid crystal layers 501 to 510 are oriented at -22 degrees, -20 degrees, -18 degrees, -16 degrees, -14 degrees, -12 degrees, and -10, respectively. The ones changed to -8 degrees, -6 degrees, and -4 degrees were used. As the liquid crystal layers 501 to 510, 5CB (4-Cyano-4'-pentylbiphenyl), which is a liquid crystal having a refractive index anisotropy of (1.71, 1.53, 1.53), was used. When the director's orientation is 0 degrees, 5CB is in a state of lying down, which is tilted clockwise in stages from -22 degrees to -4 degrees. The simulation results are shown in FIG. FIG. 25 shows the whole image of the light field. From FIG. 25, an optical field confined in the two-dimensional waveguide was confirmed, and it was shown that the two-dimensional waveguide light conversion of the three-dimensional propagating light is feasible by this structure as well.

According to this third embodiment, the same advantages as those of the first embodiment can be obtained.

<Fourth Embodiment>
[Photoelectric converter]
In the photoelectric conversion device according to the fourth embodiment, unlike the photoelectric conversion device according to the first embodiment, the waveguide structure 100 having a refractive index anisotropy shown in FIG. 26 is used as the optical waveguide section 10. .. Although not shown, the light incident surface of the waveguide structure 100 is provided with the light traveling direction conversion layer 30 as in the first embodiment. The semiconductor layer 21 of the intermediate band type solar cell 20 is bonded to the light emitting end surface of the waveguide structure 100.

As shown in FIG. 26, the waveguide structure 100 is incident on the light incident surface of the light traveling direction conversion layer 30 and has the traveling direction changed in the direction perpendicular to the light incident surface, and is finally directed. The purpose is to convert the traveling direction of the light into a direction perpendicular to the traveling direction (horizontal direction in FIG. 26). Since the waveguide direction is one direction (right side in FIG. 26), the waveguide structure 100 is an asymmetric waveguide. The waveguide structure 100 is composed of a plurality of layers 101 to 108 having different refractive indexes from each other (the layer 107 has a wedge-shaped shape). The layers 101 to 108 are formed by, for example, a plurality of liquid crystal layers having different coordination directions from each other, or a plurality of isotropic media partitioned by a non-parallel interface (for example, an interface having a jagged cross section). The refractive index distribution of layers 101 to 108 in the direction perpendicular to FIG. 26 has translational symmetry.

A simulation was performed to verify the effect of the waveguide structure 100. In FIG. 26, the horizontal axis is the x-axis, the vertical axis is the z-axis, and the paper depth direction is the y-axis. The layers 101 to 108 of the waveguide structure 100 were set as follows. That is, the

layers

101 and 102 are composed of an isotropic substance having a refractive index n = 1.01, and the layer 103 has a refractive index of light traveling in the (x, y, z) direction of (2,2,1). The layer 104 is composed of an anisotropic substance having anisotropy, the layer 104 is composed of the anisotropic substance rotated clockwise by 15 degrees in the xz plane, and the layer 105 is composed of the anisotropic substance rotated clockwise in the xz plane. The layer 106 is composed of the anisotropic substance rotated 32 degrees in the direction and rotated 45 degrees clockwise in the xz plane, and the layer 107 is composed of the anisotropic substance rotated 45 degrees clockwise in the xz plane. The layer 108 was composed of an isotropic material having a refractive index of n = 1.01. The result of the simulation is shown in FIG. 27. FIG. 27 shows the distribution of the magnitude (intensity) of the amplitude E _y in the y-axis direction of the electric field of the light wave in the xz plane. From FIG. 27, the light incident on the waveguide structure 100 from the vertical direction is gradually bent in the traveling direction to the right side in the figure while passing through the waveguide structure 100, and finally emitted in the substantially horizontal direction. You can see that. That is, it can be seen that the waveguide structure 100 can convert the traveling direction of the light incident on the waveguide structure 100 in the vertical direction into a direction substantially perpendicular to the traveling direction.

Other than the above, it is the same as the first embodiment.

According to the fourth embodiment, the same advantages as those of the first embodiment can be obtained.

<Fifth Embodiment>
[Photoelectric converter]
In the photoelectric conversion device according to the fifth embodiment, unlike the photoelectric conversion device according to the first embodiment, the optical waveguide unit 300 shown in FIG. 28 is used instead of the optical waveguide unit 10. As shown in FIG. 28, the optical waveguide 300 includes a planar optical waveguide 310 and a layer having a transparent refractive index anisotropy provided on the main surface of the planar optical waveguide 310 (hereinafter, “refraction”). It has a (referred to as a rate anisotropic medium layer) 320 and a reflector array 330 provided on the refractive index anisotropic medium layer 320.

The substance constituting the planar optical waveguide 310 is for light having a wavelength in the range targeted by this photoelectric conversion device, for example, light in a main wavelength band of the solar spectrum (ultraviolet light, visible light, infrared light). It is desirable that the substance is as transparent as possible. The substance constituting the planar optical waveguide 310 is generally transparent glass, high refractive index glass, transparent plastic or the like. Examples of the transparent plastic include polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polystyrene, polyethylene, polypropylene, polyphenylene sulfide, polyvinylidene fluoride, acetylcellulose, brominated phenoxy, aramids, polyimides, polystyrenes, polyarylates, etc. Examples thereof include polysulfones and polyolefins. As the substance constituting the planar optical waveguide 10, a fluorine-based material used for plastic optical fiber (POF) or the like is particularly suitable due to its low light loss property. The thickness of the planar optical waveguide 310 is selected as needed, and is, for example, 1 to 1000 μm. The size (length and width) of the planar optical waveguide 310 is appropriately selected depending on the location where the photoelectric conversion device is installed, but is generally (1 cm to 1 m) × (1 cm to 1 m). be.

The planar shape of the planar optical waveguide 310 is not particularly limited and is appropriately selected depending on the application of the photoelectric conversion device and the like, but is, for example, a rectangle or a square.

The reflecting mirror array 330 has a structure in which the reflecting mirror 331 and the transparent layer 332 are alternately and repeatedly provided in one direction parallel to the refractive index anisotropic medium layer 320. The details of the reflector array 330 are described in Patent Document 1, but the outline is as follows. The reflector 331 is made of a metal such as silver (Ag), a silver alloy (Ag-Pd or the like), or aluminum (Al). The transparent layer 332 is preferably made of a transparent substance (transparent glass, transparent resin, etc.) having a refractive index substantially equal to that of the transparent substance constituting the planar optical waveguide 310. The thickness of the transparent layer 332 in one direction parallel to the refractive index anisotropic medium layer 320 is selected as necessary, and is, for example, several μm to several tens of μm. Further, the period of repetition of the reflecting mirror 331 and the transparent layer 332, that is, the total thickness of one reflecting mirror 331 and the transparent layer 332 adjacent thereto in one direction parallel to the refractive index anisotropic medium layer 320. The ratio of the thickness of the reflector 331 to the sword is preferably small, and is selected to be at least 5% or less, preferably 1% or less, and 1 nm or more. The reflector 331 is typically provided periodically so that the spacing of the reflectors 331 may be changed regularly or irregularly in some or all of the reflector array 330, but of incident light. In order to prevent omission (incident light is not reflected by the reflector 331 and directly hits the planar optical waveguide 310), and when two reflectors 331 adjacent to each other are focused on in FIG. 28, the left side is facing. The structure and arrangement are set so that the light reflected by the reflector 331 is not reflected (scattered) by the back surface of the reflector 331 on the right side. The spacing between the reflectors 331 and the number of iterations between the reflectors 331 and the transparent layer 332 are selected as needed. The reflecting mirror 331 is configured to be able to reflect the three-dimensional space propagating light incident from the outside through the light traveling direction changing layer 30 and make it incident on the refractive index anisotropic medium layer 320. Preferably, the reflecting mirror 331 reflects the three-dimensional space propagating light transmitted through the light traveling direction conversion layer 30 and is incident on the refractive index anisotropic medium layer 320 at an incident angle within a certain range. The cross-sectional shape is selected so that it can be done. FIG. 28 shows, as a typical example, the case where the shape of the reflector 331 in the cross section perpendicular to the main surface of the planar optical waveguide 310 of the reflector array 330 forms a part of one side of the axis of the parabola. Has been done. When three-dimensional space propagating light is incident on the reflector array 330 from almost perpendicular direction, the axis of this parabolic line is set so that as much light as possible is finally incident on the planar optical waveguide 310. , It is preferably set within ± 10 ° with respect to the normal line erected on the main surface of the planar optical waveguide 310, and most preferably near 0 °, that is, set perpendicular to the main surface of the planar optical waveguide 310. Will be done. Since light incident parallel to the axis of the parabola has the property of concentrating at the focal point of the parabola, by setting the axis of the parabola perpendicular to the main surface of the planar optical waveguide 310, it is almost perpendicular to the reflector array 330. When the three-dimensional space propagating light is incident, the directions of the light reflected by the reflector 331 are almost the same. In order to allow as much incident light incident on the optical waveguide 310 to enter the planar optical waveguide 310 as much as possible, the reflector 331 is preferably provided extending from end to end of the planar optical waveguide 310. However, it is not limited to this. The planar shape of each reflecting mirror 331 is not particularly limited and is selected as necessary, but typically, it is reflected by the reflecting mirror 331 and passes through the refractive index anisotropic medium layer 320 to pass through the refractive index anisotropic medium layer 320, and the planar optical waveguide 310. At least most of the two-dimensional spatially propagating light incident on the interior of the is selected to be directed in a certain direction.

As shown in FIG. 28, in the refractive index anisotropic medium layer 320, the incident light (three-dimensional space propagating light) from the outside is reflected by the reflector 331 of the reflector array 330 to reflect the refractive index anisotropic medium layer 320. The refractive index in the direction toward (A direction) and the refractive index in the direction perpendicular to this direction (B direction) are different from each other, and the refractive index in the A direction is larger than the refractive index in the B direction. The refractive index in the A direction is substantially the same as the refractive index of the planar optical waveguide 310 and the transparent layer 332, so that the light reflected by the reflector 331 is the planar optical waveguide 310 from the refractive index anisotropic medium layer 320. It is allowed to enter the inside of the planar optical waveguide 310. On the other hand, the direction in which the light reflected on the back surface of the planar optical waveguide 310 after passing through the refractive index anisotropic medium layer 320 and entering the inside of the planar optical waveguide 310 is approximately the B direction, is B. The refractive index in the direction is sufficiently smaller than the refractive index of the planar optical waveguide 310, so that the main surface of the planar optical waveguide 310 is reflected by the back surface of the planar optical waveguide 310 by satisfying the condition of total internal reflection. The light obliquely crossing the planar optical waveguide 310 and incident on the main surface thereof is totally reflected at the interface between the planar optical waveguide 310 and the refractive index anisotropic medium layer 320. The medium having the refractive index anisotropy constituting the refractive index anisotropy medium layer 320 is not particularly limited, but is most typically made of a liquid crystal display, for example. Now, for the sake of simplicity, the liquid crystal molecule is approximated to a uniaxial permittivity ellipse, and its permittivity in the major axis direction is described as ε // and its permittivity in the minor axis direction is described as ε⊥, which is typical anisotropy. As an example, consider the case where ε // −ε⊥> 0. In this case, if the refractive index of the liquid crystal molecule in the major axis direction is n // and the refractive index in the minor axis direction is n⊥, then n //> n⊥ is established. However, (n //) ² to ε // and (n⊥) ² to ε⊥. In the opposite case, that is, when ε // −ε⊥ <0, the orientation of the liquid crystal molecules is set so that the light incident on the planar optical waveguide 310 feels a relatively large refractive index. The liquid crystal can be used by controlling the above.

According to this fifth embodiment, the same advantages as those of the first embodiment can be obtained.

<Sixth Embodiment>
[Photoelectric converter]
In the photoelectric conversion device according to the sixth embodiment, unlike the photoelectric conversion device according to the first embodiment, the optical waveguide section 400 shown in FIG. 29 is used instead of the optical waveguide section 10. As shown in FIG. 29, in this photoelectric conversion device, a flat plate-shaped reflector array 330 and a reflector array 330 in which one main surface constitutes an optical incident surface and the other main surface constitutes a light emitting surface. The optical waveguide portion 400 is composed of an asymmetric planar optical waveguide 410 having a wedge-shaped shape provided on the other main surface of the above. The reflector array 330 is the same as in the third embodiment. The angle of inclination of the slope with respect to the bottom surface of the asymmetric surface optical waveguide 410 is selected as necessary, but is typically 10 ° or less, for example, 7 °. The planar shape of the reflector array 330 and the asymmetrical optical waveguide 410 is not particularly limited and may be appropriately selected depending on the photoelectric conversion device or the like, and is, for example, a rectangle or a square. An optical traveling direction conversion layer 30 is provided on the light incident surface of the optical waveguide portion 400, and an intermediate band type solar cell 20 is provided on the light emission end surface of the asymmetric planar optical waveguide 20.

The wedge-shaped asymmetric planar optical waveguide 410 has an elongated right-angled triangular cross-sectional shape, the long side (bottom side) sandwiching the right-angled corner coincides with the light emitting surface of the reflector array 330, and the short side is asymmetric. It coincides with the light emitting end face of the planar optical waveguide 410.

The substance constituting the asymmetric planar optical waveguide 410 is the same as that of the planar optical waveguide 310 of the third embodiment.

The configuration of the photoelectric conversion unit including the intermediate band type solar cell 20 may be as shown in FIG. That is, as shown in FIG. 30, the photoelectric conversion unit is composed of N intermediate band type solar cells 20 connected in series. By doing so, it is possible to bring about an increase in the output voltage of the photoelectric conversion device, which is very effective in practical use.

Other than the above, it is the same as the first embodiment.

[Operation of photoelectric conversion device]
The operation of the photoelectric conversion device will be described. As shown in FIG. 31, the light incident on the light traveling direction conversion layer 30 from the outside is incident on the reflector array 330 after the traveling direction is changed in the direction perpendicular to the light traveling direction conversion layer 30. The light thus incident on the reflector array 330 from the vertical direction is reflected by each reflector 331 of the reflector array 330 and then enters the inside of the asymmetrical optical waveguide 410. The light that has entered the inside of the asymmetrical planar optical waveguide 410 is repeatedly totally reflected at the interface between the bottom surface of the asymmetrical planar optical waveguide 410, the asymmetrical planar optical waveguide 410, and the air layer, and the asymmetrical planar optical waveguide 410 has a tapered shape. Since the cross-sectional area gradually increases toward the intermediate band type solar cell 20, the inside of the asymmetrical optical waveguide 410 is waveguideed in the direction of the arrow, and the light is emitted from the light emission end surface of the asymmetrical optical waveguide 410. Finally, it is incident on the side surface of the semiconductor layer 21 of the intermediate band type solar cell 20 to perform optical conversion. Electron-hole pairs are generated in the semiconductor layer 21 in the process of the waveguide light traveling in the semiconductor layer 21. Then, the electrons and holes thus generated move in the semiconductor layer 21 by drift or diffusion, and are collected on one and the other of the first electrode 22 and the second electrode 23. In this way, photoelectric conversion is performed in the semiconductor layer 21, and a current (photocurrent) is taken out from the first electrode 22 and the second electrode 23 to the outside.

According to this sixth embodiment, the same advantages as those of the first embodiment can be obtained.

<7th embodiment>
[Photoelectric converter]
The photoelectric conversion device according to the seventh embodiment is different from the photoelectric conversion device according to the second embodiment in that the optical waveguide 10 shown in FIG. 32 is used instead of the optical waveguide 10 shown in FIG. The composition of is the same. FIG. 32 is a cross-sectional view showing a part of the optical waveguide section 10 showing higher waveguide efficiency. In the optical waveguide section 10, a plurality of optical introduction core layers 14 in the transverse direction (x-axis direction) are used as subunits (in FIG. 32, four optical introduction core layers 14 included in one subsystem (4 slots)). (Is shown an example of), the direction orthogonal to the light traveling direction in the second arcuate portion 122 (part of the oblong ellipse portion) of the clad layer 12 at the end of the subsystem (that is, substantially perpendicular to the tangential direction of the oblong ellipse). The thickness of the second arcuate portion 122 in the direction) is expanded to 0.4 to 0.5 μm. The thickness of the other portion of the second arcuate portion 122 is the same as that shown in FIG. That is, the thickness thereof is an effective clad layer width obtained from the average tangential angle of the second arc-shaped portion 122: about 0.4 × sin (5 °) to 0.035 μm. In the optical waveguide portion 10 shown in FIG. 17, both the second arc-shaped portion 122 (part of the horizontally elongated elliptical portion) and the first arc-shaped portion 121 (part of the vertically elongated elliptical portion) of the clad layer 12 are in the x-axis direction. The width of the light introduction core layer 14 is constant. On the other hand, as shown in FIG. 32, in the optical waveguide section 10, the optical introduction core is divided into subunits composed of a plurality of optical introduction core layers 14 (four in FIG. 32) in the x-axis direction. The thickness of the layer 14 is set large. For example, assuming that the width of the relatively thin clad layer 12 is 0.4 μm, the width of the light-introduced core layer 14 with the increased thickness is 3.4 μm, and the width of the other light-introduced core layer 14 is 2. It is 26 μm.

A simulation of light propagation in this photoelectric conversion device was performed. The simulation result is shown in FIG. 33. FIG. 33 shows the whole image of the light field. In FIG. 33, the 16th, 17th, 18th, and 19th are the 16th, 17th, 18th, and 19th optical introduction cores to the right, with the optical introduction core layer 14 at the left end of FIG. 32 as the 0th. The layer 14 is shown. From FIG. 33, it can be seen that higher waveguide efficiency is obtained.

According to this seventh embodiment, the same advantages as those of the second embodiment can be obtained.

<8th embodiment>
[Cylinder installed with photoelectric conversion device]
FIG. 34 shows a photoelectric conversion device installation cylinder according to the eighth embodiment. The photoelectric conversion device installation cylinder is typically installed with its lower end embedded in the ground, but is not limited thereto.

As shown in FIG. 34, in this photoelectric conversion device installation cylinder, a cylindrical photoelectric conversion device 600 is installed as a whole so as to surround the outer circumference of the cylinder 500. As shown in FIG. 2, the overall shape of the photoelectric conversion device 600 when developed in a plane in a direction perpendicular to the central axis of the cylinder 500 is a rectangle.

FIG. 35 shows a cross section of the portion including the photoelectric conversion device 600 of the cylinder in which the photoelectric conversion device is installed. As shown in FIG. 35, a cylindrical waveguide core layer 13 is provided so as to surround the outer periphery of the cylinder 500, and both sides of the intermediate band type solar cell 20 are sandwiched between the waveguide core layers 13. An optical waveguide portion 10 and an optical traveling direction conversion layer 30 are provided on the waveguide core layer 13. FIG. 36 shows an enlarged part of the optical waveguide portion 10 and the optical traveling direction conversion layer 30 shown in FIG. 35. As shown in FIG. 36, in this case, in the optical waveguide section 10, one half on the left side in FIG. 36 is configured in the same manner as the optical waveguide section 10 shown in FIG. 1, and one half on the right side in FIG. 36 is one half on the left side. It is configured symmetrically with. That is, the one-sided half on the right side and the one-sided half on the left side of FIG. 36 of the optical waveguide portion 10 are symmetrically configured.

FIG. 37A is an enlarged plan view of the intermediate band type solar cell 20 and the waveguide core layer 13 on both sides thereof, FIG. 37B is a side view of this portion, and FIG. 37C is a cross-sectional view of this portion. As shown in FIGS. 37B and 37C, the intermediate band type solar cells 20 are M (M is an integer of 2 or more) intermediate band type solar cells 20-1 stacked in a direction parallel to the central axis of the cylinder. It consists of 20-2, ..., 20-k, ..., 20-M. Each intermediate band type solar cell 20-k has the same configuration as the intermediate band type solar cell 20 of the first embodiment. The pn junction surface of the semiconductor layer constituting each intermediate band type solar cell 20-k is schematically shown by a broken line. A first electrode 22 and a second electrode 23 are provided above and below each intermediate band type solar cell 20-k, but are not shown in FIGS. 37B and 37C. The host semiconductor of each intermediate band type solar cell 20-k is selected as necessary as in the first embodiment, and may be, for example, a single composition of Si alone, as shown in FIG. 7. It may be composed of a plurality of host semiconductors whose band gap gradually decreases in the traveling direction of light.

The operation of the photoelectric conversion device 600 of the cylindrical photoelectric conversion device installation column will be described. As shown in FIG. 35, when the photoelectric conversion device installation cylinder is installed on the ground, the optical waveguide portion 10 and the optical traveling direction conversion layer 30 are oriented toward the south side. At this time, sunlight, which is three-dimensional propagating light, is incident on the light traveling direction conversion layer 30 from the south surface. The traveling direction of the sun incident on the south surface is converted into a direction perpendicular to the light incident surface 10a by the light traveling direction conversion layer 30, and the sunlight is incident on the optical waveguide section 10. In this case, the light incident on one half of the left side of FIG. 36 of the optical waveguide portion 10 is converted into two-dimensional propagating light and travels in the waveguide core layer 13 in one direction on the left side of FIG. It becomes light and is incident on one end surface of each intermediate band type solar cell 20-k parallel to the pn junction surface. On the other hand, the light incident on one half of the right side of FIG. 36 of the optical waveguide 10 is converted into two-dimensional propagating light and travels in the waveguide core layer 13 in one direction on the right side of FIG. Then, it is incident on the other end surface of each intermediate band type solar cell 20-k in parallel with the pn junction surface. In this way, photoelectric conversion is performed by the light incident on both end faces of each intermediate band type solar cell 20-k.

In order to verify the waveguide performance of the optical waveguide of the photoelectric conversion device 600 of the cylindrical photoelectric conversion device installed, the region shown by the alternate long and short dash line in FIG. 37A was simulated. FIG. 38 shows the result (light field) of the simulation. However, the diameter of the cylinder 500 was 50 mm, and the refractive index of the waveguide core layer 13 was the refractive index of polydimethylsiloxane (PDMS). From FIG. 38, it can be seen that light is efficiently guided in the cylindrical waveguide core layer 13.

According to this eighth embodiment, it is possible to realize a photoelectric conversion device installation cylinder capable of high-efficiency power generation by the photoelectric conversion device 600, and it is inexpensively configured by using the existing telegraph pole as the utility pole 500. can do.

<9th embodiment>
[Cylinder installed with photoelectric conversion device]
In the photoelectric conversion device installation cylinder according to the ninth embodiment, the intermediate band type solar cell 20 of the photoelectric conversion device 600 is different from the photoelectric conversion device installation cylinder according to the eighth embodiment. 39A is an enlarged plan view of the intermediate band type solar cell 20 of the photoelectric conversion device 600 and the waveguide core layer 13 of the portions on both sides thereof, FIG. 39B is a side view of this portion, and FIG. 39C is a side view of this portion. It is a cross-sectional view and corresponds to FIGS. 37A, 37B and 37C, respectively. As shown in FIGS. 39A, 39B and 39C, in this photoelectric conversion device 600, two vertically long intermediate band type solar cells 20 elongated in the central axis direction of the cylinder 500 are stacked in the diameter direction of the cylinder 500, and these are laminated. Both ends of the two intermediate band type solar cells 20 are sandwiched between the waveguide core layer 13. The pn junction surface of the intermediate band type solar cell 20 is schematically shown by a broken line. The pn junction surface of the intermediate band type solar cell 20 is parallel to the waveguide core layer 13.

The operation of the photoelectric conversion device 600 of the cylindrical photoelectric conversion device installation column is the same as that of the eighth embodiment.

According to this ninth embodiment, the same advantages as those of the eighth embodiment can be obtained.

<10th embodiment>
[Cylinder installed with photoelectric conversion device]
FIG. 40 shows a photoelectric conversion device installation cylinder according to the tenth embodiment. As shown in FIG. 40, in this photoelectric conversion device installation cylinder, in addition to the cylindrical photoelectric conversion device 600 being installed on the outer circumference of the cylinder 500 as in the eighth embodiment, the top of the cylinder 500 It is different from the photoelectric conversion device installation cylinder according to the eighth embodiment that the photoelectric conversion device 700 is installed in the.

FIG. 41 shows the top of the cylinder 500 and the vertical cross section of the photoelectric conversion device 700. As shown in FIG. 41, in the photoelectric conversion device 700, the waveguide core layer 13 is provided so as to cover the top of the cylinder 500. FIG. 41 shows a case where the top of the cylinder 500 is hemispherical and the waveguide core layer 13 is hemispherical, but the present invention is not limited to this, and the shape of the top of the cylinder 500 is other than the hemisphere. The waveguide core layer 13 may also have a shape other than the hemisphere. An optical waveguide portion 10 and an optical traveling direction conversion layer 30 are provided on the waveguide core layer 13. In this case, the clad layer 12 and the optical introduction core layer 14 of the optical waveguide 10 are configured rotationally symmetrically around the central axis of the photoelectric conversion device 700. An intermediate band type solar cell 20 is provided at the lowermost end of the waveguide core layer 13 (a portion corresponding to the equator of the hemisphere).

The operation of the photoelectric conversion device 700 of the cylinder on which the photoelectric conversion device is installed will be described. The operation of the photoelectric conversion device 600 is the same as that of the eighth embodiment. This photoelectric conversion device installation cylinder is installed in the same manner as in the eighth embodiment. As shown in FIG. 41, the sunlight incident on the light traveling direction conversion layer 30 from above the photoelectric conversion device 700 is converted into a direction in which the traveling direction is perpendicular to the light incident surface 10a and is incident on the optical waveguide section 10. The light incident on the optical waveguide portion 10 propagates radially downward in the waveguide core layer 13 and finally incidents on the intermediate band type solar cell 20 at the lowermost end of the waveguide core layer 13 to perform photoelectric conversion. Is done.

According to the tenth embodiment, in addition to the same advantages as those of the eighth embodiment, the photoelectric conversion device 600 and the photoelectric conversion device 700 have an advantage that the power generation capacity can be improved. Can be done.

<11th embodiment>
[Building with photoelectric conversion device]
FIG. 42 shows a building in which a photoelectric conversion device is installed according to the eleventh embodiment.

As shown in FIG. 42, in this photoelectric conversion device-installed building, the surface of the photoelectric conversion device-installed portion of the outer wall 800a of the building 800 is configured in a corrugated sheet shape having unevenness in the horizontal direction. A rectangular photoelectric conversion device 900 that is curved in a corrugated plate shape is installed on the surface of the shape. The overall shape of the photoelectric conversion device 900 when unfolded on a plane is a rectangle as shown in FIG.

FIG. 43 shows a cross section of the outer wall 800a of the building 800 of the building where the photoelectric conversion device is installed. As shown in FIG. 43, the waveguide core layer 13 is provided on the corrugated surface of the outer wall 800a, and both sides of the intermediate band type solar cell 20 are sandwiched between the waveguide core layers 13. The cross-sectional shape of the waveguide core layer 13 may be a continuous curved shape and may be selected as necessary, and the convex portions and the concave portions may have any shape, but in FIG. 43, the radii are mutual as an example. The case where it has a waveform in which the same upper semicircle and the lower semicircle are smoothly and alternately connected is shown. The intermediate band type solar cell 20 is the same as that of the first embodiment. The optical waveguide portion 10 and the optical traveling direction conversion layer 30 are provided on the waveguide core layer 13 curved in a corrugated shape. In this case, the optical waveguide 10 of each convex portion of the waveguide core layer 13 has one two-dimensional propagating light in the waveguide core layer 13 toward the intermediate band type solar cell 20 as in the eighth embodiment. It is configured to travel in a direction.

The operation of the photoelectric conversion device 900 in the building where the photoelectric conversion device is installed will be described. As shown in FIG. 43, in this photoelectric conversion device installation building, the photoelectric conversion device 900 is installed so as to face the south side. At this time, sunlight, which is three-dimensional propagating light, is incident on the light traveling direction conversion layer 30, the traveling direction is converted to a direction perpendicular to the light incident surface 10a by the light traveling direction conversion layer 30, and the light is incident on the optical waveguide section 10. do. In this case, the light incident on one half of the left side of FIG. 43 of the optical waveguide portion 10 of each convex portion of the waveguide core layer 13 is converted into two-dimensional propagating light, and the inside of the waveguide core layer 13 is the left side in FIG. 43. As it travels in the direction, the light incident on one half of the right side of FIG. 43 of the optical waveguide section 10 is converted into two-dimensional propagating light and travels in the waveguide core layer 13 in one direction on the right side of FIG. 43, and finally. It is collected in the intermediate band type solar cell 20 and incident on both end faces in parallel with the pn junction surface. In this way, photoelectric conversion is performed by the light incident on both end faces of the intermediate band type solar cell 20.

According to the eleventh embodiment, it is possible to realize a building with a photoelectric conversion device capable of high-efficiency power generation by the photoelectric conversion device 900 installed on the outer wall 800a.

<12th embodiment>
[Cylinder installed with photoelectric conversion device]
As shown in FIG. 44, the photoelectric conversion device installation cylinder according to the twelfth embodiment has high white reflection between the clad layer 11 inside the cylindrical waveguide core layer 13 of the photoelectric conversion device 600 and the cylinder 500. The reflectance layer 1000 is provided, the optical traveling direction conversion layer 30 and the optical waveguide portion 10 are not provided, and the clad layer 15 is provided on the surface of the waveguide core layer 13 opposite to the clad layer 11. It is different from the photoelectric conversion device installation cylinder according to the eighth embodiment. Other things are the same as those of the eighth embodiment. The white high reflectance layer 1000 can be formed, for example, by using fine particles of barium sulfate as a main raw material and applying a white paint having an extremely high solar reflectance of 98.1% (see Non-Patent Document 9). ..

In this case, since the white high reflectance layer 1000 is provided between the clad layer 11 of the waveguide core layer 13 and the cylinder 500, the incident angle φ ₂ of light on the inner clad layer 11 is set.
φ ₂ = φ ₁ + ξ (4)
With the establishment of, the angle ξ of the light incident on the outer clad layer 15 is larger _than the angle φ1. Therefore, it becomes easier to satisfy the total reflection condition in the inner clad layer 11, and the white color existing under the clad layer 11 due to the shallow penetration of the two-dimensional propagating light that waveguides through the waveguide core layer 13. Invasion into the high reflectance layer 1000 is also suppressed, and scattering by the white high reflectance layer 1000 is eliminated, so that the waveguide efficiency of the waveguide core layer 13, which is a two-dimensional waveguide on the side surface of the cylinder 500, is improved. You can get a big advantage.

FIG. 45 shows the results of measuring the waveguide efficiency and the reflected light intensity from the white high reflectance layer 1000 with respect to the reflection angle θ by the white high reflectance layer 1000 of the south surface incident sunlight shown in FIG. 44. In FIG. 45, the curve A shows the direction (θ) dependence of the reflected light intensity from the white high reflectance layer 1000, and the curve B shows the direction (θ) dependence of the waveguide efficiency of the cylindrical waveguide core layer 13. .. As shown in FIG. 45, among the light scattered in various directions (indicated by the curve A) by the white high-reflectivity layer 1000, the light in a certain direction (indicated by the curve B) is waveguideed. The curve C (after standardization), which is the product, is the amount of light reaching the intermediate band type solar cell 20 existing on the north surface (not shown in FIG. 44). From this result, it is expected that 10 to 20% of the total incident light will be guided.

FIG. 46A shows a sample in which a high-reflectivity blank paper is wound as a white high-reflection layer 1000 on the outer peripheral surface of a cylinder 500 having a diameter of 50 mm, and a cylindrical waveguide core layer 13 is provided through the high-reflection blank paper. It is a photograph (actual photograph of a light field) of the state when green light (corresponding to the south surface incident sunlight of FIG. 44) is incident from the direction perpendicular to the cylinder 500. From FIG. 46A, it is clear that the entire sample is green and green light is guided to the entire waveguide core layer 13. FIG. 46B is a photograph (actual photograph of the light field) taken when the sample is curved in an arc shape in a state where green light is incident from a direction perpendicular to the cylinder 500. From FIG. 46B, it is clear that the entire sample exhibits green color even in the curved state, and green light is guided to the entire waveguide core layer 13. This result is consistent with the result shown in FIG.

According to the twelfth embodiment, the same advantages as those of the eighth embodiment can be obtained.

Although the embodiments of the present invention have been specifically described above, the present invention is not limited to the above-described embodiments, and various modifications based on the technical idea of the present invention are possible.

For example, in the twelfth embodiment, the outer clad layer 15 and the inner clad layer 11 of the waveguide core layer 13 provided on the side surface of the cylinder 500 are provided concentrically, but they are centered. It is also effective to give the same effect as the case where the waveguide core layer 13 has a locally tapered structure by forming the shape including a part of the shifted circle. That is, the effect of the local taper angle is added to the ξ of the above equation (4), and a further effect can be obtained. Further, the intermediate band type solar cell 20 having an edge light incident arrangement installed at the end of the waveguide core layer 13 can also use a pn junction made of a single semiconductor. Examples of such an element include, for example, a silicon-based Mountain Chip manufactured by MHGoPower of Taiwan. Furthermore, by incorporating an intermediate band type solar cell 20 or a general solar cell in an arrangement in which light is incident perpendicularly to the pn junction surface at the end of the waveguide core layer 13, the voltage that is a feature of the condensing system can be further incorporated. You can benefit from the improvement in conversion efficiency that accompanies the rise. Further, the photoelectric conversion device 900 having the corrugated plate-shaped waveguide core layer 13 used in the eleventh embodiment can be installed on the bonnet or the roof portion of various automobiles such as electric vehicles (EVs). Further, by combining the photoelectric conversion device 900 having the corrugated board-shaped waveguide core layer 13 and the photoelectric conversion device 900 having the hemispherical waveguide core layer 13 used in the tenth embodiment, for example, in the past years. Almost the entire surface of a car with a unique roundness, such as a famous car, can be covered with a photoelectric conversion device.

Further, the numerical values, materials, shapes, arrangements, etc. given in the above-described embodiment are merely examples, and different numerical values, materials, shapes, arrangements, etc. may be used as necessary.

10, 300, 400

Optical waveguide

11, 12 Clad layer 13 waveguide core layer 14 Optical introduction core layer 20 Intermediate band type solar cell 21 Semiconductor layer 22 First electrode 23 Second electrode 30 Optical traveling direction conversion layer 31 Transparent Substrate 32 Rotating release object-like part 33 Hemispherical part 40 Substrate 213 Intermediate band forming layer 213 Intermediate band forming layer 500

Cylindrical

600, 700, 900 Photoelectric converter 800 Building

Claims

Light receiving part and
A photoelectric conversion unit composed of an intermediate band type solar cell, which is spatially separated from the light receiving unit,
A spatially asymmetric waveguide that connects the light receiving unit and the photoelectric conversion unit and has a function of converting the traveling direction of light.
Have,
The photoelectric conversion unit is provided at the end of the waveguide on the light emitting side.
A photoelectric conversion device configured so that the direction of light emitted from the end of the waveguide on the light emitting side is substantially parallel to the semiconductor layer constituting the intermediate band type solar cell.
The photoelectric conversion device according to claim 1, wherein the intermediate band of the intermediate band type solar cell is formed of a semiconductor having a single or multiple quantum well structure.
The photoelectric conversion device according to claim 1, wherein the intermediate band of the intermediate band type solar cell is formed of a semiconductor having a quantum dot structure.
The photoelectric conversion device according to claim 2, wherein the semiconductor forming the intermediate band of the intermediate band type solar cell is a GaInN-based semiconductor.
The photoelectric conversion device according to claim 1, wherein the light receiving portion has a light traveling direction conversion layer that converts the traveling direction of light incident on the light receiving portion into a direction substantially perpendicular to the light receiving portion.
The light traveling direction changing layer is
A transparent substrate having a first refractive index and
A plurality of rotating object-like portions made of the transparent material having the first refractive index provided in a two-dimensional array on one main surface of the transparent substrate, and
It has a surface made of a hemisphere provided so as to cover each of the rotating release objects, and has a hemispherical portion having a second refractive index smaller than that of the first refractive index.
The photoelectric conversion device according to claim 5, wherein the focal point of the rotating object-shaped portion and the center of the hemispherical portion coincide with each other.
The above waveguide
A two-dimensional waveguide with continuous translational symmetry with respect to the waveguide direction,
Light whose traveling direction is converted in a direction substantially perpendicular to the light receiving surface of the light receiving portion by the light traveling direction conversion layer provided between the two-dimensional waveguide and the light traveling direction conversion layer is received. The photoelectric conversion device according to claim 5, wherein the photoelectric conversion device comprises a waveguide structure having discrete translational symmetry having a refractive index anisotropy layer at least a part thereof, which propagates asymmetrically in only one direction parallel to a plane. ..
The photoelectric conversion device according to claim 7, wherein the waveguide structure includes at least a plurality of liquid crystal layers having different director directions from each other.
The photoelectric conversion device according to claim 7, wherein the waveguide structure includes a plurality of isotropic media partitioned by non-parallel interfaces from each other at least in a part thereof.
The light receiving part and the waveguide
A waveguide core layer with continuous translational symmetry with respect to the waveguide direction,
The waveguide core layer is discontinuously covered, and a clad layer having discrete translational symmetry with respect to the waveguide direction is provided.
The clad layer is separated from the waveguide core layer at the end of the breaking portion that does not cover the waveguide core layer, on the side opposite to the waveguide direction of the waveguide core layer with respect to the cutting portion, and away from the waveguide core layer. It extends between the positions and gradually approaches the waveguide core layer toward the waveguide direction of the waveguide core layer, and the tangent line at the end of the disconnection portion is parallel to or substantially equal to the waveguide core layer. It has a structure provided in parallel as a part of it,
The photoelectric conversion device according to claim 1, wherein a light-introducing core layer coated with the cladding layer is provided at the disconnection portion of the cladding layer so as to merge with the waveguide core layer.
The shape of the cross section of the clad layer perpendicular to the plane of the waveguide core layer and parallel to the waveguide direction of the waveguide core layer consists of a combination curve including a part of an arc or an ellipse in at least a part thereof. The photoelectric conversion device according to claim 10.
The shape of the cross section of the clad layer perpendicular to the surface of the waveguide core layer and parallel to the waveguide direction of the waveguide core layer is an ellipse whose long axis is perpendicular to the waveguide direction of the waveguide core layer. The photoelectric conversion device according to claim 10, further comprising a combination curve of a part and a part of an ellipse or an arc whose major axis is parallel to the waveguide direction of the waveguide core layer.
The photoelectric conversion device according to claim 1, wherein the waveguide has a wedge-shaped shape in which the cross-sectional area gradually increases toward the end face on the light emitting side.
The photoelectric conversion device according to claim 1, wherein the waveguide is a two-dimensional waveguide having a planar or curved overall shape.
The photoelectric conversion device according to claim 14, wherein the two-dimensional waveguide has a cylindrical, semicircular, or corrugated shape.
The photoelectric conversion device according to claim 1, which has a white high reflectance layer on the inner surface of the two-dimensional waveguide having a cylindrical, semicircular or corrugated shape.
The photoelectric conversion device according to claim 1, wherein the photoelectric conversion device is an optical wireless power supply device.
It has at least one photoelectric conversion device and has
The above photoelectric conversion device
Light receiving part and
A photoelectric conversion unit composed of an intermediate band type solar cell, which is spatially separated from the light receiving unit,
A spatially asymmetric waveguide that connects the light receiving unit and the photoelectric conversion unit and has a function of converting the traveling direction of light.
Have,
The photoelectric conversion unit is provided at the end of the waveguide on the light emitting side.
A building that is a photoelectric conversion device configured so that the direction of light emitted from the end of the waveguide on the light emitting side is substantially parallel to the semiconductor layer constituting the intermediate band type solar cell.
It has at least one photoelectric conversion device and has
The above photoelectric conversion device
Light receiving part and
A photoelectric conversion unit composed of an intermediate band type solar cell, which is spatially separated from the light receiving unit,
A spatially asymmetric waveguide that connects the light receiving unit and the photoelectric conversion unit and has a function of converting the traveling direction of light.
Have,
The photoelectric conversion unit is provided at the end of the waveguide on the light emitting side.
A moving body that is a photoelectric conversion device configured so that the direction of light emitted from the end of the waveguide on the light emitting side is substantially parallel to the semiconductor layer constituting the intermediate band type solar cell.