JP2006066707A - Photoelectric conversion apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photoelectric conversion apparatus having structure laminating a plurality of photoelectric conversion units each of which includes a photoelectric conversion layer and having a photoelectric conversion function, capable of selecting an electric connection format between a plurality of photoelectric conversion units, optimizing a material of an electrode brought into contact with each photoelectric conversion layer to the photoelectric conversion layer, and simply and compactly forming lamination structure free from the risk of liquid leakage. <P>SOLUTION: An organic semiconductor solar battery 7 consists of an ITO electrode 2, a light receiving power generation layer 3, and an aluminium electrode 4. An organic semiconductor solar battery 8 consisting of the aluminium electrode 4, a light receiving power generation layer 5, and an ITO electrode 6 is laminated on the organic semiconductor solar battery 7, and these two organic semiconductor solar batteries 7, 8 are connected in parallel with an external load 9. The aluminium electrode 4 is formed by a thin film deposited on the whole surface and having about 10 nm film thickness and a mesh patterned like a mesh and evaporated and has light transmissivity. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a photoelectric conversion device such as a photovoltaic cell that generates an electromotive force by converting light energy into electrical energy, or an organic electroluminescence device that generates light by converting electrical energy into light energy.

  As an energy source to replace fossil fuel, solar cells that convert light energy of sunlight into electric energy have attracted attention and various studies have been conducted.

  Solar cells that use pn junctions of inorganic semiconductor materials such as silicon show relatively high photoelectric conversion efficiency and are currently most popular. However, there are processes for manufacturing high-purity semiconductor materials and processes for forming pn junctions. There is a problem that the energy consumption in the manufacturing process is large and the equipment cost is high.

  As a method of solving this problem, a photochemical cell that generates an electromotive force by bringing a photo-semiconductor that generates a carrier upon irradiation with light into contact with an electrolyte solution, and photoinduced electron transfer that occurs at the interface between the two and a subsequent electrochemical reaction. Has been proposed (A. Fujishima, K. Honda, Nature, 238, 37 (1972)).

  Furthermore, according to Grezel et al., An oxide semiconductor having a photosensitizing dye attached to the surface is brought into contact with an electrolyte solution, and photoinduced electron transfer induced by light absorption of the photosensitizing dye is followed by an electrochemical reaction. Dye-sensitized photochemical cells that generate electromotive force have been proposed (Patent Publication No. 2664194, J. Am. Chem. Soc. (1993), 115, 6382-6390, Nature (1991), 353, 737-). 740 etc.), expected as a new generation solar cell.

  The above-mentioned photochemical battery has an advantage that a photoelectric conversion element can be produced at low cost using an inexpensive oxide semiconductor such as titanium dioxide. In particular, the dye-sensitized photochemical battery absorbs by changing the photosensitizing dye to be used. There is an advantage that the wavelength of light to be selected can be selected, or light in a wide wavelength region can be used by combining a plurality of photosensitizing dyes.

  In addition, with the progress of organic semiconductor technology in recent years, solar cells using organic semiconductors have been proposed. FIG. 12 is a cross-sectional view (a) showing the structure of a general organic semiconductor solar cell and its equivalent circuit (b). In this organic semiconductor solar battery, a transparent electrode 102 made of ITO (Indium Tin Oxide) or the like, a photoelectric conversion layer 103 made of an organic semiconductor polymer material, and a counter electrode 104 made of aluminum or the like are laminated on a transparent substrate 101 to produce photoelectric. The basic structure is a structure in which an organic semiconductor polymer layer 103 as a conversion layer is sandwiched between two types of electrodes having different work functions (Akinori Kuno, Applied Physics, 71, (4), 425-427 (2002) Christoph J. Brabec, N. Serdar Sariciftci, Jan C. Hummelen, Adv. Funct. Mater., 11, 15-26 (2001)).

  As an operating principle model of organic semiconductor solar cells, organic semiconductor molecules absorb light and become excitons, charge separation occurs at the interface with the internal electric field due to transfer of excitation energy, holes move to electrodes with a large work function, A model in which electrons flow to an electrode having a small work function is generally used.

  The organic semiconductor solar cell has features such that it can be manufactured by a low-cost process using an inexpensive organic semiconductor material, can be formed on a flexible plastic substrate, and can easily be increased in area. Further, there is an advantage that the wavelength of light to be absorbed can be selected by changing the organic semiconductor material to be used, or light in a wide wavelength region can be used by combining a plurality of organic semiconductor materials. Furthermore, it is stable against mechanical impact, and the dye-sensitized photochemical cell requires a liquid electrolyte layer, whereas the organic semiconductor solar cell is advantageous in that it is easy to handle because it is solid.

  However, dye-sensitized photochemical cells and organic semiconductor solar cells have a problem that the achieved photoelectric conversion efficiency is lower than that of silicon-based solar cells and is not sufficient. The main cause of this is that the thickness of the light absorption region where photoelectric conversion is effectively performed is not sufficient. That is, in the dye-sensitized photochemical cell, the region where light absorption that leads to photoelectric conversion occurs is limited to the surface of the oxide semiconductor to which the photosensitizing dye is attached, and sufficient light absorption cannot be performed. Moreover, in the organic semiconductor solar cell, the thickness of the organic semiconductor polymer layer 103 must be equal to or less than the diffusion length of excitons, and the thickness of the semiconductor polymer layer 103 is increased in order to suppress an increase in film resistance. For example, it is necessary to suppress to about 100 nm. For this reason, sufficient light absorption cannot be performed.

  In order to solve this problem, a member that reflects light, such as a metal electrode, conventionally used in these batteries is replaced with a member that transmits light, and a plurality of batteries are stacked. A proposal has been made to improve the photoelectric conversion efficiency as a result of increasing the light utilization rate by absorbing the light that could not be absorbed by this battery in the subsequent battery.

  FIG. 13 is a cross-sectional view illustrating a configuration of a photoelectric conversion element disclosed in Patent Document 1 described later. This photoelectric conversion element is mainly composed of electrolyte layers 112a and 112b, semiconductor electrodes 111a and 111b provided on both sides of the electrolyte layer 112, and a counter electrode 114 provided in the center, and a semiconductor electrode on the light incident side. 111a, electrolyte layer 112a, and counter electrode 114 constitute one photovoltaic cell 110a, and the opposite semiconductor electrode 111b, electrolyte layer 112b, and counter electrode 114 constitute another photovoltaic cell 110b. These two photovoltaic cells are diodes. They are connected in parallel via 114a and 114b.

  The photoelectric conversion element is characterized in that the counter electrode 114 is an electrode formed in a mesh shape using, for example, a metal wire and is configured to have sufficient light transmittance. Therefore, not only the semiconductor electrode 111a of the photocell 110a on the light incident side but also the semiconductor electrode 111b of the photocell 110b on the opposite side is irradiated with sufficient light, and photoelectric conversion is also performed in the photocell 110b. Compared with the element provided in (1), the light utilization efficiency is improved.

  FIG. 14 is a cross-sectional view showing a configuration of an organic semiconductor element 120 disclosed in Patent Document 2 described later. In the organic semiconductor element 120, a functional organic thin film layer 123 that exhibits various functions by flowing a space charge limited current (SCLC) between the anode 121 and the cathode 122, and floating conductive The body thin film layers 124 are alternately stacked.

  The conductor thin film layer 124 is light transmissive and has dark conductivity by a method such as doping a metal thin film having a thickness of several nanometers to several tens of nanometers, a thin film of metal oxide, an acceptor, or a donor. It is an organic semiconductor thin film that is expressed and is preferably in ohmic contact with the functional organic thin film layer 123.

  In the organic semiconductor element 120, for example, when the functional organic thin film layer 123 is a light emitting layer that emits light by injection of electrons and holes, it is in contact with one functional organic thin film layer 123 above and below. Two conductor thin film layers 124 (or electrodes 1 or 2) function as one organic electroluminescent element (hereinafter sometimes referred to as an organic EL element). Therefore, when n functional organic thin film layers 123 are stacked, n organic EL elements are stacked in one organic semiconductor element 120 and connected in series.

  When a voltage is applied to the electrodes 1 and 2, electrons and holes are injected into each functional organic thin film layer 123, and light is emitted. Since the conductor thin film layer 124 is light transmissive, this light passes through the conductor thin film layer 124 and is extracted from the end face of the organic semiconductor element 120.

  FIG. 14 shows an example in which an external power source 125 is connected to the organic semiconductor element 120 and functions as an organic EL element by applying voltage or injecting current. However, the functional organic thin film layer 123 converts light energy into electrical energy. The organic semiconductor element 120 has a function of generating an electromotive force by conversion, and when the organic semiconductor element 120 functions as an organic semiconductor solar cell without applying an external voltage or injecting an electric current, as shown in FIG. Patent Document 2 describes that the structure of the semiconductor element 120 is effective.

  In this case, the functional organic thin film layer 123 and the two conductor thin film layers 124 (or the electrodes 1 or 2) in contact therewith function as one organic semiconductor solar cell. Therefore, when n functional organic thin film layers 123 are stacked, n organic semiconductor solar cells are stacked in one organic semiconductor element 120 and connected in series.

  When light is incident from one end face of the organic semiconductor element 120, a part of the incident light is absorbed and functionally converted by the functional organic thin film layer 123 at the light incident end. Since the body thin film layer 124 is light transmissive, it passes through the conductor thin film layer 124 and enters the adjacent functional organic thin film layer 123. Here, part of the incident light is absorbed and photoelectrically converted by the functional organic thin film layer 123, while the light that has not been absorbed passes through the conductive thin film layer 124 and is further adjacent to the functional organic thin film layer 123. Is incident on.

  Thus, in the organic semiconductor element 120, the light that has not been absorbed by the functional organic thin film layer 123 in the previous stage is sent to the functional organic thin film layer 123 in the subsequent stage, and photoelectric conversion is also performed there. As compared with an element in which the conductive organic thin film layer 123 is provided alone, the light utilization rate is improved.

JP 2000-260492 (4th page, FIG. 1) JP 2003-264085 (7th, 8th and 10-12 pages, FIG. 1)

  However, in the photochemical battery and the dye-sensitized photochemical battery described in Patent Document 1, since an electrolyte solution must be used, the structure becomes complicated, processing takes time, and there is a risk of liquid leakage. . In addition, it is necessary to provide a transparent substrate on both sides of the electrolyte layer, and there is also a problem that when this structural unit is laminated, the thickness becomes too large.

  In the organic semiconductor element described in Patent Document 2, since the organic semiconductor polymer is solid, a laminated structure can be easily formed, and there is no risk of liquid leakage. However, in this organic semiconductor element 120, electrodes are provided only at both ends of a laminate in which the functional organic thin film layers 123 and the conductor thin film layers 124 are alternately laminated, and connection terminals are provided on the intermediate conductor thin film layer 124. The structure is not provided. For this reason, the following problem arises.

  An organic functional element such as an organic EL element or an organic semiconductor solar cell formed by the functional organic thin film layer 123 and the two conductive thin film layers 124 (or the electrodes 1 or 2) in contact with the upper and lower sides is as follows: Connection types other than series connection, for example, parallel connection cannot be taken. In series connection, the current flowing through each connected organic functional element must be the same, so that the performance of other elements is limited by the element with the lowest performance among the organic functional elements connected in series. There is. For example, when the organic semiconductor element 120 is applied as an organic semiconductor solar cell, the output current is limited to the same magnitude as the output current of the organic semiconductor solar cell with the lowest power generation performance included in the organic semiconductor element 120. . Moreover, there is a problem that the internal resistance of the battery is the sum of the internal resistances of the organic semiconductor solar cells and becomes too large.

  In addition, the direction of the current flowing through the laminated body is determined in one direction, in which each conductive thin film layer 124 is sandwiched between the functional organic thin film layers 123 on both sides. For this reason, each conductor thin film layer 124 functions as a positive electrode (or an anode) for one functional organic thin film layer 123 and as a negative electrode (or a cathode) for the other functional organic thin film layer 123. It is extremely difficult and practically impossible to provide each conductive thin film layer 124 having an optimum work function and the like for every functional organic thin film layer 123.

  The present invention has been made in view of the circumstances as described above, and an object of the present invention is to arrange a plurality of photoelectric conversion units including a photoelectric conversion layer and having a photoelectric conversion function. It is possible to select the electrical connection form between the photoelectric conversion units, and the electrode material in contact with the photoelectric conversion layer can be optimized for each photoelectric conversion layer. It is an object of the present invention to provide a photoelectric conversion device that can easily and compactly form a laminated structure that does not have the risk of being damaged.

  That is, the present invention is a photoelectric conversion device having a solid photoelectric conversion layer, which is a light transmissive first electrode, a first photoelectric conversion layer, a light transmissive second electrode, and a second photoelectric conversion. A structure in which a layer and a light-transmitting third electrode are stacked as a structural unit, and among the electrodes including the first electrode, the second electrode, and the third electrode, predetermined electrodes are connected in parallel A photoelectric conversion device having a solid photoelectric conversion layer, the light-transmitting first electrode, the photoelectric conversion layer, and the light-transmitting first photoelectric conversion device. The second photoelectric conversion device has a structure in which two electrodes are stacked in this order as a structural unit, and a plurality of the structural units are stacked and connected in series in the stacking direction of the stacked body. Is.

  According to the photoelectric conversion device of the present invention, since the solid photoelectric conversion layer is provided, there is no risk of liquid leakage, and a simple and compact laminated structure can be formed. In addition, since the first electrode, the second electrode, and the third electrode are light transmissive, light transmission is not blocked by the electrodes. For this reason, when the photoelectric conversion device is configured as a photovoltaic cell, photoelectric conversion is performed in at least one pair of the first photoelectric conversion layer and the second photoelectric conversion layer in the first photoelectric conversion device, In the second photoelectric conversion device, photoelectric conversion is performed by a plurality of the photoelectric conversion layers, so that the light utilization rate can be increased and the photoelectric conversion efficiency can be improved as compared with the case where a single photoelectric conversion layer is used. Moreover, incident light can be taken in from either side of both end surfaces in the stacking direction, and convenience is improved. When the photoelectric conversion device is configured as an electroluminescent device, the first photoelectric conversion device performs photoelectric conversion between at least one pair of the first photoelectric conversion layer and the second photoelectric conversion layer. In the photoelectric conversion device 2, photoelectric conversion is performed by the plurality of photoelectric conversion layers, and light emitted from these photoelectric conversion layers is emitted together, so that the luminance of the light source is improved. Further, the emitted light can be extracted from either side of the both end surfaces in the stacking direction, and convenience is improved.

  In the first photoelectric conversion device of the present invention, a structure in which the first electrode, the first photoelectric conversion layer, the second electrode, the second photoelectric conversion layer, and the third electrode are stacked is a structural unit. Therefore, it is composed of the photoelectric conversion unit composed of the first electrode, the first photoelectric conversion layer, and the second electrode, the second electrode, the second photoelectric conversion layer, and the third electrode. Since a predetermined structure is connected in parallel among the electrodes including the first electrode, the second electrode, and the third electrode, these photoelectric conversion units can be formed. The conversion units can be electrically connected in a predetermined connection form including parallel connection.

  At this time, the first electrode is in contact with only the first photoelectric conversion layer, the third electrode is in contact with only the second photoelectric conversion layer, and is in contact with the first photoelectric conversion layer and the second photoelectric conversion layer. Since the second electrode also does not usually serve as a positive electrode and a negative electrode (or an anode and a cathode), a material having an optimum work function for the first photoelectric conversion layer and the second photoelectric conversion layer is used as each electrode material. You can choose. Note that in an apparatus in which photoelectric conversion units are connected in parallel, there is an advantage that even if one photoelectric conversion unit stops functioning in an insulated state, the other units are not affected.

  In the second photoelectric conversion device of the present invention, a structure in which the first electrode, the photoelectric conversion layer, and the second electrode are stacked in this order is a structural unit, and a plurality of the structural units are stacked. Therefore, it is possible to form a stacked structure of photoelectric conversion units including the first electrode, the photoelectric conversion layer, and the second electrode, and these photoelectric conversion units are connected in series. At this time, unlike the conductor thin film layer of Patent Document 2, the first electrode and the second electrode are in contact with only the photoelectric conversion layer, so that the work function and the like are optimal for the photoelectric conversion layer. A material can be selected for each electrode material. Although this structure increases the number of electrodes, there is an advantage that the photoelectric conversion device can be configured by repeating the simplest structure. In addition, in the apparatus which connects a photoelectric conversion unit in series, even if one photoelectric conversion unit stops a function in a short circuit state, there exists an advantage which can keep the influence which affects other units to the minimum.

  In the first photoelectric conversion device of the present invention, a structure in which the first electrode, the first photoelectric conversion layer, the second electrode, the second photoelectric conversion layer, and the third electrode are stacked in this order; It is preferable to have a stacked body with structures stacked in the reverse order. At this time, it is preferable that the first electrode, the second electrode, and the third electrode are connected in parallel. If it does in this way, the said 3rd electrode can be shared by a lower photoelectric conversion unit and an upper photoelectric conversion unit, the said photoelectric conversion apparatus can be comprised with few electrodes, and the said photoelectric conversion layer occupies The ratio can be increased.

  In addition, there is a laminated body in which a plurality of structures in which the first electrode, the first photoelectric conversion layer, the second electrode, the second photoelectric conversion layer, and the third electrode are laminated in this order are laminated. The plurality of structures are preferably insulated from each other. At this time, it is preferable that the first electrode, the second electrode, and the third electrode are connected in parallel. Although this structure has a slightly larger number of parts than the above structure, there is an advantage that the photoelectric conversion device can be configured by repeating a simple structure.

  The first photoelectric conversion layer and the second photoelectric conversion layer, and the first electrode and the third electrode may be made of the same material, and the first electrode and the third electrode may be connected. . When the first photoelectric conversion layer and the second photoelectric conversion layer, and the first electrode and the third electrode are made of the same material, the upper photoelectric conversion unit and the lower photoelectric Since the electrical characteristics of the conversion unit are the same, the first electrode and the third electrode can be directly connected in parallel, and the wiring structure is simplified.

  In the first and second photoelectric conversion devices of the present invention, the first and second photoelectric conversion layers may be light receiving layers made of an organic semiconductor layer, and may be configured as a photovoltaic cell.

  At this time, it is preferable that a light reflection layer is provided on the end surface opposite to the light incident side. If it does in this way, the light which permeate | transmitted can be returned to the said 1st and 2nd photoelectric converting layer once again, and the utilization factor of light can be raised.

  The organic semiconductor layer is preferably made of a mixture in which a photoelectron donor and an acceptor are joined, and in particular, a bulk heterojunction of a donor and an acceptor is formed. Unlike a normal junction where the donor layer and the acceptor layer are in contact with each other, the bulk heterojunction forms a boundary region where the donor layer and the acceptor layer enter each other's layers, and the boundary region is vertically and horizontally inside the boundary region. A complex-shaped joint surface is formed so as to wrap around, and the region where excitons generated by light absorption can reach the joint surface extends to the entire boundary region, so that the photoelectric conversion efficiency is dramatically improved (Peter Peumans, Soichi Uchida and Stephen R. Forrest, Nature, 425, 158-162 (2003)).

  The donor is preferably a p-type semiconductor molecule such as a polymer having a π electron conjugated system or a dye-containing polymer, and the acceptor is preferably an n-type semiconductor polymer or fullerene. Specifically, poly (2-methoxy-5- (2′-ethylhexyloxy) -1,4-phenylenevinylene) (MEH-PPV) which is a donor of an organic polymer compound and 6,6 which is a fullerene derivative. A combination with -phenyl-C61 butyric acid methyl ester (PCBM) may be used. In addition, a combination of MEH-PPV and cyano-PPV (CN-PPV), which are organic polymer compound donors and acceptors, and a copper phthalocyanine complex (CuPc), which is a low molecular weight organic compound donor and acceptor, In combination with 3,4,9,10-perylenetetracarboxylic-bis-benzimidazole (PTCBI), poly (3-hexylthiophene) (P3HT) and cadmium selenide (organic semiconductor donor and inorganic semiconductor acceptor) CdSe) may also be used in combination.

  A plurality of the light receiving layers that absorb light having different wavelengths may be stacked. If it does in this way, the utilization factor of light can be raised.

  Further, it is preferable that the dye introduced into the light receiving layer has a color filter function. In this way, various colors can be formed and used in the design.

  Also, by controlling the film thickness of the laminated structure and suppressing the surface reflection of light of the wavelength used for power generation by multiple reflection interference, or confining the light in the laminated structure, improving the light utilization rate, more Light can contribute to power generation.

  Alternatively, the first and second photoelectric conversion layers may be light emitting layers made of organic semiconductor layers, and may be configured as an organic electroluminescent device.

  At this time, a light reflection layer is preferably provided on one end face. By doing in this way, light can be gathered on one side and an organic electroluminescent apparatus with high brightness | luminance can be comprised.

  In addition, it is preferable that a plurality of the light-emitting layers that emit light having different wavelengths are stacked, and light resulting from a mixed color of the plurality of light emission is emitted. In this way, various colors can be formed and used in the design.

  Next, a preferred embodiment of the present invention will be described specifically and in detail with reference to the drawings.

Embodiment 1
In the first embodiment, the light-transmissive first electrode, the first photoelectric conversion layer, the light-transmissive second electrode, the second photoelectric conversion layer, and It consists of 1 unit of the structural unit laminated | stacked with the light transmissive 3rd electrode, As described in Claim 6, the said 1st photoelectric converting layer and said 2nd photoelectric converting layer which are the said light reception layers, and the said The example which comprised the 1st electrode and the said 3rd electrode with the same material, and comprised the said 1st electrode and the said 3rd electrode as the said photovoltaic cell as described in Claim 8. is there.

  FIG. 1 is an explanatory diagram showing the structure of a photovoltaic cell based on the first embodiment. FIG. 1 (a) is an exploded perspective view of a part of the photovoltaic cell for easy understanding of the structure, FIG. 1 (b) is a sectional view of the photovoltaic cell, and FIG. 1 (c) is an equivalent thereof. It is a circuit diagram. However, in the perspective view of FIG. 1A, the transparent substrate 1 is not shown (the same applies to FIGS. 2 to 4 showing modified examples described later).

  In this photovoltaic cell, one organic layer is formed by a photoelectric conversion unit including an ITO (Indium Tin Oxide) electrode 2 as the first electrode, a light-receiving power generation layer 3 as the first photoelectric conversion layer, and an aluminum electrode 4 as the second electrode. A semiconductor solar cell 7 is formed, and another one is formed by a photoelectric conversion unit comprising the ITO electrode 6 as the third electrode, the light receiving power generation layer 5 as the second photoelectric conversion layer, and the aluminum electrode 4 as the second electrode. Two organic semiconductor solar cells 8 are formed, and these two organic semiconductor solar cells are connected in parallel to the external load 9 as shown in FIG.

  The reason why conventional common organic semiconductor solar cells cannot be stacked is that the counter electrode 104 made of a metal such as aluminum is formed on the entire surface as shown in FIG. There is in being. Therefore, in the first embodiment, it is possible to stack the batteries by making the aluminum electrode 4 have a structure that transmits light. In the photovoltaic cell shown in FIG. 1, both sides of an aluminum electrode 4 having light transmittance are sandwiched between light receiving power generation layers 3 and 5, and both outer sides thereof are electrodes having different types of light transmittance, here ITO electrodes 2 and 6. It has a vertically symmetrical structure. Hereinafter, each part of the photovoltaic cell including the manufacturing method will be described.

  The transparent substrate 1 is a transparent substrate such as a glass substrate. In order to reduce the cost of the photovoltaic cell or to provide flexibility so that it can be installed on a curved surface, it is preferable to use a transparent plastic film substrate, for example, a plastic substrate made of polycarbonate or polyethylene terephthalate.

An ITO electrode 2 made of an ITO thin film is formed on the transparent substrate 1 as the light transmissive first electrode. The ITO electrode 2 is formed by sputtering, for example, to a thickness of 100 nm, a film resistance of 10Ω, and a film resistivity of 1 × 10 ⁻⁴ Ω · cm. As the transparent electrode, a transparent conductive film made of tin oxide (ATO or FTO) doped with antimony or fluorine in addition to ITO, zinc oxide, or the like can be used, and can be formed by a sputtering method, a vacuum evaporation method, or the like. .

  On the ITO electrode 2, a light receiving power generation layer 3 is formed as the first photoelectric conversion layer which is the light receiving layer. The light-receiving power generation layer 3 is preferably made of, for example, a mixture in which a donor that receives light and emits photoelectrons and an acceptor that receives the photoelectrons and realizes charge separation are joined. The donor is preferably a p-type semiconductor molecule such as a polymer having a π electron conjugated system or a dye-containing polymer, and the acceptor is preferably an n-type semiconductor polymer or fullerene.

  Specifically, MEH-PPV is used as a donor and PCBM is used as an acceptor. FIG. 2 is an explanatory diagram showing the molecular structure of MEH-PPV and PCBM.

  For example, a mixed solution (2 wt%) in which MEH-PPV and PCBM are dissolved in chlorobenzene at a mass ratio of 1: 4 is applied onto the ITO electrode 2 by spin coating, and the chlorobenzene is evaporated to form a mixture thin film. The light receiving power generation layer 3 is formed. The light receiving power generation layer 3 is preferably formed to a thickness of about 200 nm by spin-coating the above mixed solution at 3000 rpm for 30 seconds.

  On the light receiving power generation layer 3, an aluminum electrode 4 is formed as an electrode having optical transparency. The aluminum electrode 4 is formed by the following two processes.

  First, an aluminum thin film 4a is formed on the entire surface of the light receiving power generation layer 3 by vapor deposition. The aluminum thin film 4a is formed as thin as about 10 nm so that light is sufficiently transmitted.

  Next, an aluminum mesh 4b is vapor-deposited on the aluminum thin film 4a while patterning into a mesh shape using a metal mask. The aluminum mesh 4b has, for example, a film thickness of about 100 nm, a line width of 60 μm, and a pitch of 500 μm. The aluminum mesh 4b has a sufficient thickness and a sufficient thickness and has sufficient conductivity and strength while ensuring light transmission through the gaps in the mesh portion, and also functions as a support for the aluminum thin film 4a. To do.

  The organic semiconductor solar cell 7 is formed by the ITO electrode 2, the light receiving power generation layer 3, and the aluminum electrode 4 described above.

  A light receiving power generation layer 5 is formed on the aluminum electrode 4 in the same manner as the light receiving power generation layer 3, and an ITO electrode 6 is stacked thereon to form another organic semiconductor solar cell 8. When the ITO electrode 6 is formed by sputtering, initially, the sputtering power is set as small as possible so that the ITO fine particles do not penetrate the light receiving power generation layer 5 by sputtering. For example, sputtering is performed at 80 W for the first 30 minutes, and then sputtering is performed at 160 W for 30 minutes.

  When light is incident from one end face of the photovoltaic cell thus formed, part of the incident light is absorbed and photoelectrically converted by the light receiving power generation layer 3 at the light incident end, while the light that has not been absorbed is Since the aluminum electrode 4 is light transmissive, it passes through the aluminum electrode 4 and enters the light receiving power generation layer 5. Again, part of the incident light is absorbed and photoelectrically converted by the light receiving power generation layer 5. In this way, the light that has not been absorbed by the light receiving power generation layer 3 in the previous stage is transmitted to the light receiving power generation layer 5 in the subsequent stage, and is also subjected to photoelectric conversion there. Therefore, in the photovoltaic cell of the present embodiment, the light receiving power generation layer 3 The utilization factor of light is improved as compared with a photovoltaic cell provided alone.

  At this time, in the organic semiconductor solar cell 7 or 8, electrons flow to the aluminum electrode 4 having a low work function, and holes flow to the ITO electrode 2 or 6 having a high work function, so that the ITO electrodes 2 and 6 become positive electrodes. The aluminum electrode 4 becomes a negative electrode. As a result, the current flows downward in the light receiving power generation layer 3, the current flows downward in the light receiving power generation layer 5, and the directions in which the current flows in the two light receiving power generation layers 3 and 5 are reversed. The aluminum electrode 4 is in contact with the two light receiving power generation layers 3 and 5, but functions as a negative electrode for both layers, and the characteristics of aluminum with a small work function are effective for both layers. It is alive.

  Here, an example is shown in which a positive electrode made of ITO and a negative electrode made of aluminum are provided, but the present invention is not limited to this. More generally, according to the structure of the photovoltaic cell of the present embodiment, the positive electrode and the negative electrode can be formed using an electrode material having an appropriate work function or the like in accordance with the characteristics of the light receiving power generation layers 3 and 5. Therefore, the performance of the light receiving power generation layers 3 and 5 can be sufficiently exhibited. As a result, improvement in photoelectric conversion efficiency can be achieved by improving the light utilization rate by stacking the organic semiconductor solar cells.

  On the other hand, in the solar cell using the organic semiconductor element disclosed in Patent Document 2, as described above, the conductive thin film layer 124 is positive with respect to one functional organic thin film layer 123 in contact therewith. As a negative electrode for the other functional organic thin film layer 123. For this reason, it is very difficult to select an appropriate material for the conductive thin film layer 124 for both of the two functional organic thin film layers 123 in contact therewith. As a result, the performance of each functional organic thin film layer 123 cannot be sufficiently exhibited, and it is difficult to achieve improvement in photoelectric conversion efficiency even if the light utilization rate is improved by stacking. In this respect, the photovoltaic cell of the present embodiment is essentially different from the organic semiconductor element disclosed in Patent Document 2.

  As a selection criterion other than the work function to be considered when selecting an electrode material, it is possible to form a light transmissive electrode except for the electrode opposite to the light incident side, and it is stable in the atmosphere. Can be mentioned.

  In the photovoltaic cell based on this Embodiment, since the light receiving power generation layers 3 and 5 and the ITO electrodes 2 and 6 are formed of the same material, the photovoltaic power of the organic semiconductor solar cells 7 and 8 is the same. Therefore, as shown in FIGS. 1B and 1C, the ITO electrodes 2 and 6 can be directly connected, and the organic semiconductor solar cells 7 and 8 can be connected in parallel to the external load 9, and the wiring The structure becomes simple.

  Although FIG. 1 shows the case where light is incident from below, the light may be incident from above. In the photovoltaic cell based on this Embodiment, incident light can be taken in from either side of both end surfaces in the stacking direction, and convenience is improved.

  FIG. 3 is a perspective view showing a modification of the first embodiment. In this photovoltaic cell, a light reflecting layer 11 is provided on one end face. In this way, the transmitted light can be returned again to the light receiving power generation layers 3 and 5, and the light utilization rate can be increased.

  FIG. 4 is a perspective view showing another modification of the first embodiment. In this photovoltaic cell, instead of the ITO electrodes 2 and 6, it is made of a metal having a work function larger than that of aluminum, and, like the aluminum electrode 4, is composed of a metal thin film and a metal mesh and has light transmissivity. And are used. As the metal having a large work function, for example, gold or platinum is preferable.

  FIG. 5 is a perspective view showing still another modification of the first embodiment. In this photovoltaic cell, instead of the aluminum electrode 4, an electrode 14 made of a metal oxide having a work function smaller than that of ITO, for example, zinc oxide ZnO is used. As a method for forming the metal oxide electrode 14, a sputtering method with little thermal damage is preferable.

Embodiment 2
In the second embodiment, the first electrode, the first photoelectric conversion layer, the second electrode, the second photoelectric conversion layer, and the third electrode described in claims 2 and 3 are stacked in this order. The smallest of the photoelectric conversion devices having a stacked body of a structure and a structure stacked in the reverse order, in which the first electrode, the second electrode, and the third electrode are respectively connected in parallel. It is the example which comprised the apparatus of the structure as a photovoltaic cell.

  FIG. 6A is a cross-sectional view showing the structure of the photovoltaic cell based on the present embodiment, and FIG. 6B is an equivalent circuit diagram thereof.

  In this photovoltaic cell, a first electrode 21 such as ITO, a first photoelectric conversion layer 22 that is a light receiving power generation layer, a second electrode 23 such as an aluminum electrode, a second photoelectric conversion layer 24 that is a light receiving power generation layer, and a second photoelectric conversion layer 24 such as ITO. On the structure in which the three electrodes 25 are laminated in this order, the third electrode 25, the second photoelectric conversion layer 26, the second electrode 27, the first photoelectric conversion layer 28, and the first electrode 29 in the reverse order described above. Are stacked in the reverse order. Here, the modifiers of “first”, “second”, and “third” are, for example, that the electrodes given “first” have the same material and the layer structure formed above and below them. It shall be used as a word indicating that it has an equivalent function (the same applies hereinafter).

  The structure includes a first photoelectric conversion unit 31 including a first electrode 21, a first photoelectric conversion layer 22, and a second electrode 23, a second electrode 23, a second photoelectric conversion layer 24, and a third electrode. The second photoelectric conversion unit 32 composed of the second photoelectric conversion unit 25 is included, and the structure stacked in the reverse order includes a third electrode 25, a second photoelectric conversion layer 26, and a second electrode 27. The first photoelectric conversion unit 33 includes the first photoelectric conversion unit 33 including the second photoelectric conversion unit 33, the second electrode 27, the first photoelectric conversion layer 28, and the first electrode 29. The unit 32 shares the second electrode 23, the second photoelectric conversion unit 32 and the second photoelectric conversion unit 33 share the third electrode 25, and the second photoelectric conversion unit 33 and the first photoelectric conversion unit 34 The second electrode 27 is shared. The first and second photoelectric conversion units 31, 34, 32, and 33 function as organic semiconductor solar cells.

  Thus, in the photovoltaic cell based on this Embodiment, since it considers that the electrode can be shared between the two photoelectric conversion units located up and down of one electrode, when a photoelectric conversion unit is laminated | stacked, an electrode The number can be minimized, and light loss due to reflection and scattering at the electrode can be minimized. Further, if the thickness of the stacked body is suppressed from increasing with the thickness of the electrode and the thickness of the stacked body is made the same, more photoelectric conversion units can be included.

  The first electrodes 21 and 29 and the third electrode 25 are made of a material having a high work function, and the second electrodes 23 and 27 are made of a material having a low work function. The electrodes are arranged alternately in the stacking direction. Conversely, the first electrode and the third electrode can be formed of a material having a low work function, and the second electrode can be formed of a material having a high work function.

  When light is incident from one end face of the thus formed photovoltaic cell, a part of the incident light is absorbed and photoelectrically converted by the first photoelectric conversion layer 22 at the light incident end, but the light that has not been absorbed. Since the second electrode 23 is light-transmitting, it passes through the second electrode 23 and enters the second photoelectric conversion layer 24. Also here, a part of the incident light is absorbed and photoelectrically converted by the second photoelectric conversion layer 24. As described above, the light that has not been absorbed by the first photoelectric conversion layer 22 in the previous stage is transmitted to the second photoelectric conversion layers 24 and 26 or the first photoelectric conversion layer 28 in the subsequent stage, and photoelectric conversion is also performed there. In the photovoltaic cell of the present embodiment, the light utilization rate is improved as compared with the photovoltaic cell in which the first photoelectric conversion layer 22 is provided alone.

  At this time, in each of the photoelectric conversion units 31 to 34, electrons flow to the second electrode having a low work function, and holes flow to the first electrode or the third electrode having a high work function. The third electrode 25 functions as a positive electrode in any photoelectric conversion unit, and the second electrodes 23 and 27 function as a negative electrode in any photoelectric conversion unit, and one electrode never serves as a positive electrode and a negative electrode. As described above, in any photoelectric conversion unit, an electrode having a large work function functions as a positive electrode, and an electrode having a small work function functions as a negative electrode, and the characteristics of each electrode are effectively utilized.

  In such a case, since the positive electrode and the negative electrode can be formed by selecting an electrode material having an appropriate work function or the like in accordance with the characteristics of the photoelectric conversion layer, as in Embodiment 1, the performance of the photoelectric conversion layer Can be fully exhibited. As a result, improvement in photoelectric conversion efficiency can be achieved by improving the light utilization rate by stacking the organic semiconductor solar cells.

  On the other hand, as described above, in the solar cell based on the organic semiconductor element disclosed in Patent Document 2, since there are electrodes only at both ends in the stacking direction, there is no other way for current to flow in the stack in one direction. The conductive thin film layer 124 must function as a positive electrode for one functional organic thin film layer 123 in contact with the conductive thin film layer 124 and function as a negative electrode for the other functional organic thin film layer 123. For this reason, it is very difficult to select an appropriate material for the conductive thin film layer 124 for both of the two functional organic thin film layers 123 in contact therewith. As a result, the performance of each functional organic thin film layer 123 cannot be sufficiently exhibited, and it is difficult to achieve improvement in photoelectric conversion efficiency even if the light utilization rate is improved by stacking. In this respect, the photovoltaic cell of the present embodiment is essentially different from the organic semiconductor element disclosed in Patent Document 2.

  In the photovoltaic cell of this embodiment, the photoelectric conversion units 31 and 34 and the photoelectric conversion units 32 and 33 are formed equally, so that the photovoltaic power of each set is the same. Therefore, as shown in FIGS. 6A and 6B, the first electrode 21 and the first electrode 29, the second electrode 23 and the second electrode 27 are directly connected, and the photoelectric conversion units 31 and 34 are connected. It is preferable to connect in parallel to the external load 35 and connect the photoelectric conversion units 32 and 33 in parallel to the external load 36.

  Although FIG. 6 shows the case where light is incident from below, the light may be incident from above. In the photovoltaic cell based on this Embodiment, incident light can be taken in from either side of both end surfaces in the stacking direction, and convenience is improved.

Embodiment 3
In the third embodiment, the first electrode, the first photoelectric conversion layer, the second electrode, the second photoelectric conversion layer, and the third electrode are stacked in this order. A photoelectric conversion device having a stacked body in which a plurality of structures are stacked, wherein the structures are insulated, and the first electrode, the second electrode, and the third electrode are connected in parallel. Of these, the minimum configuration is an example of a photovoltaic cell.

  FIG. 7A is a cross-sectional view showing the structure of the photovoltaic cell based on Embodiment 3, and FIG. 7B is an equivalent circuit diagram thereof.

  In this photovoltaic cell, the structure stacked in the reverse order used in the photovoltaic cell according to the second embodiment is not used, the first electrode 41 such as ITO, the first photoelectric conversion layer 42 that is a light receiving power generation layer, aluminum A photovoltaic cell is configured by repeating only the structure in which the second electrode 43 such as an electrode, the second photoelectric conversion layer 44 that is a light receiving power generation layer, and the third electrode 45 such as ITO are laminated in this order. The body is insulated by an insulating layer 46. Although this structure has a slightly larger number of electrodes than the structure of the photovoltaic cell based on Embodiment 2, there is an advantage that a photovoltaic cell can be configured by repeating a simple structure.

  The photovoltaic cell according to the present embodiment is essentially the same as the photovoltaic cell according to the second embodiment except for the points described above. Therefore, as described below, the same features and effects as described in the second embodiment are provided. Have

  The structure includes a first photoelectric conversion unit 47 including a first electrode 41, a first photoelectric conversion layer 42, and a second electrode 43, a second electrode 43, a second photoelectric conversion layer 44, and a third electrode 45. The 2nd photoelectric conversion unit 48 comprised by these, and these function as an organic-semiconductor solar cell.

  As described above, in the photovoltaic cell of the present embodiment, the first electrode 41 and the third electrode 45 are not shared between the photoelectric conversion units, but the second electrode 43 includes the first photoelectric conversion unit 47 and the second photoelectric conversion unit 48. Therefore, the number of electrodes can be reduced and light loss due to reflection and scattering at the electrodes can be minimized. Further, if the thickness of the stacked body is suppressed from increasing with the thickness of the electrode and the thickness of the stacked body is made the same, more photoelectric conversion units can be included.

  The first electrode 21 and the third electrode 25 are formed of a material having a high work function, and the second electrode 23 is formed of a material having a low work function. Conversely, the first electrode and the third electrode can be formed of a material having a low work function, and the second electrode can be formed of a material having a high work function.

  When light is incident from one end face of the photovoltaic cell formed in this manner, a part of the incident light is absorbed and photoelectrically converted by the first photoelectric conversion layer 42 at the light incident end, but not absorbed. Since the second electrode 43 is light-transmitting, it passes through the second electrode 43 and enters the second photoelectric conversion layer 44. Again, part of the incident light is absorbed and photoelectrically converted by the second photoelectric conversion layer 44. In this way, the light that has not been absorbed by the first photoelectric conversion layer 42 in the front stage is transmitted to the second photoelectric conversion layer 44 in the rear stage or the stacked body in the rear stage, and photoelectric conversion is also performed there. In the photovoltaic cell of the embodiment, the light utilization rate is improved as compared with the photovoltaic cell in which the first photoelectric conversion layer 42 is provided alone.

  At this time, in the photoelectric conversion units 47 and 48, electrons flow to the second electrode having a low work function, and holes flow to the first electrode or the third electrode having a high work function. Functions as a positive electrode, the second electrode 43 functions as a negative electrode, and one electrode does not serve as both a positive electrode and a negative electrode. As described above, in any photoelectric conversion unit, an electrode having a large work function functions as a positive electrode, and an electrode having a small work function functions as a negative electrode, and the characteristics of each electrode are effectively utilized.

  In such a case, as in the first and second embodiments, the positive electrode and the negative electrode can be formed by selecting an electrode material having an appropriate work function in accordance with the characteristics of the photoelectric conversion layer. The performance of can be fully exhibited. As a result, improvement in photoelectric conversion efficiency can be achieved by improving the light utilization rate by stacking the organic semiconductor solar cells.

  In the photovoltaic cell of the present embodiment, the two stacked structures are the same, so the photovoltaic power of the photoelectric conversion units 47 and the photoelectric conversion units 48 are the same. Accordingly, as shown in FIGS. 7A and 7B, the first electrodes 41, the second electrodes 43, and the third electrodes 45 are directly connected to each other, and the photoelectric conversion units 47 are connected to the external load 49. It is preferable to connect the photoelectric conversion units 48 in parallel to the external load 50 by connecting them in parallel.

  Although FIG. 7 shows the case where light is incident from below, the light may be incident from above. In the photovoltaic cell based on this Embodiment, incident light can be taken in from either side of both end surfaces in the stacking direction, and convenience is improved.

Embodiment 4
In the fourth embodiment, the structure in which the light transmissive first electrode, the photoelectric conversion layer, and the light transmissive second electrode are stacked in this order as described in claim 7 is used as a structural unit. It is an example in which a plurality of the structural units are stacked and the photoelectric conversion device connected in series in the stacking direction of the stacked body is configured as a photovoltaic cell.

  FIG. 8A is a cross-sectional view showing the structure of the photovoltaic cell based on Embodiment 4, and FIG. 8B is an equivalent circuit diagram thereof.

  In this photovoltaic cell, a structure in which a first electrode 51 such as ITO, a photoelectric conversion layer 52 that is a light receiving power generation layer, and a second electrode 53 such as an aluminum electrode are laminated in this order is used as a structural unit, and the photovoltaic cell is obtained by repeating this structural unit. Configure. The photoelectric conversion unit including the first electrode 51, the photoelectric conversion layer 52, and the second electrode 53 functions as an organic semiconductor solar cell.

  The first electrode 51 is formed of a material having a high work function, and the second electrode 53 is formed of a material having a low work function. Conversely, the first electrode may be formed of a material having a low work function, and the second electrode may be formed of a material having a high work function. In any case, since the first electrode 51 and the second electrode 53 are in contact with only the photoelectric conversion layer 52, a material having an optimum work function or the like for the photoelectric conversion layer 52 can be selected as each electrode material. it can.

  When light is incident from one end face of the thus formed photovoltaic cell, a part of the incident light is absorbed and photoelectrically converted by the photoelectric conversion layer 52 of the photoelectric conversion unit 54 at the light incident end. Since the second electrode 53 and the first electrode 51 are light transmissive, the light that has not passed is transmitted through the photoelectric conversion layer 52 of the photoelectric conversion unit 55 in the next stage. Again, part of the incident light is absorbed and photoelectrically converted by the photoelectric conversion layer 52. In this way, the light that has not been absorbed by the preceding photoelectric conversion layer 52 is transmitted to the subsequent photoelectric conversion layer 52 and undergoes photoelectric conversion there, so in the photovoltaic cell according to the present embodiment, the photoelectric conversion layer 52 As compared with a photovoltaic cell in which the light source is provided alone, the light utilization rate can be improved and the photoelectric conversion efficiency can be improved.

  The structure of the photovoltaic cell based on this embodiment has a merit that the photoelectric conversion device can be configured by repeating the simplest structure, although the number of electrodes is larger than that of the photovoltaic cell based on Embodiments 1 to 3. is there. Note that since the photoelectric conversion units are connected in series, even if one photoelectric conversion unit stops functioning in a short-circuit state, there is an advantage that the influence on other units can be minimized.

  Although FIG. 8 shows the case where light is incident from below, the light may be incident from above. In the photovoltaic cell based on this Embodiment, incident light can be taken in from either side of both end surfaces in the stacking direction, and convenience is improved.

Embodiment 5
Embodiment 5 is the light transmissive first electrode according to claim 1, the first photoelectric conversion layer, the light transmissive second electrode, the second photoelectric conversion layer, and the It consists of 1 unit of the structural unit laminated | stacked with the light transmissive 3rd electrode, As described in Claim 6, the said 1st photoelectric converting layer and said 2nd photoelectric converting layer which are the said light reception layers, and the said A photoelectric conversion device in which the first electrode and the third electrode are formed of the same material and the first electrode and the third electrode are connected is configured as the organic electroluminescent device as described in claim 13. This is an example.

  FIG. 9 is a cross-sectional view showing the structure of an organic electroluminescent device based on the fifth embodiment. In this apparatus, one organic EL is formed by a photoelectric conversion unit including an ITO (Indium Tin Oxide) electrode 62 as the first electrode, a light emitting layer 63 as the first photoelectric conversion layer, and an aluminum electrode 64 as the second electrode. The element 67 is formed, and another organic EL is formed by a photoelectric conversion unit including the ITO electrode 66 as the third electrode, the light emitting layer 65 as the second photoelectric conversion layer, and the aluminum electrode 64 as the second electrode. An element 68 is formed, and these two organic EL elements are connected in parallel to the external power source 69.

  The reason why conventional conventional organic EL elements cannot be stacked and disposed is that an electrode made of a metal such as aluminum is formed on the entire surface and the light is reflected. Therefore, in the fifth embodiment, it is possible to stack the batteries by making the aluminum electrode 64 have a structure that transmits the light shown in the fifth embodiment.

  The structure of the organic electroluminescent device based on the fifth embodiment is a photovoltaic cell based on the first embodiment shown in FIG. 1 except that the material of the photoelectric conversion layer is different and an external power source 69 is connected instead of the external load 9. Since this is the same as above, we will focus on the differences.

  The transparent substrate 61 is a glass substrate or a transparent plastic film substrate, for example, a plastic substrate made of polycarbonate, polyethylene terephthalate, or the like. On the transparent substrate 61, an ITO electrode 62 made of an ITO thin film is formed as the light transmissive first electrode.

  On the ITO electrode 2, a light emitting layer 63 is formed as the first photoelectric conversion layer. The material for forming the light emitting layer 63 may be any material that forms the light emitting layer of the organic EL element, and the light emitting layer 63 is formed by a vapor deposition method or a coating method.

  On the light emitting layer 63, an aluminum electrode 64 is formed as a light transmissive electrode. The aluminum electrode 64 was deposited to a thickness of, for example, about 100 nm, a line width of 60 μm, and a pitch of 500 μm while patterning in a mesh shape using an aluminum thin film deposited on the entire surface with a thickness of about 10 nm and a metal mask on the aluminum thin film. It is formed with aluminum mesh.

  The organic EL element 67 is formed by the ITO electrode 62, the light emitting layer 63, and the aluminum electrode 64 described above. Further, a light emitting layer 65 and an ITO electrode 66 similar to the light emitting layer 63 are laminated on the aluminum electrode 64, and another organic EL element 68 is formed by the ITO electrode 66, the light emitting layer 65, and the aluminum electrode 64. Is formed.

  An external power source 69 is connected to the organic electroluminescent device formed in this way. At this time, the positive electrode of the external power supply 69 is connected to the ITO electrodes 62 and 66 having a high work function, and the positive electrode of the external power supply 69 is connected to the aluminum electrode 64 having a low work function. In this way, holes are injected from the ITO electrode 62 or 66 into the light emitting layer 63 or 65, and electrons are injected from the aluminum electrode 64 into the light emitting layer 63 or 65, thereby emitting light by the combination of holes and electrons. Occurs in the light emitting layer 63 or 65. Since the emitted light from the light emitting layer 63 or 65 is emitted together, the luminance as a light source is improved as compared with the organic electroluminescent device in which the light emitting layer is provided alone. Further, the emitted light can be extracted from either side of the both end surfaces in the stacking direction, and convenience is improved. In addition, if a light reflecting layer is provided on one end face, and a light reflecting layer is provided on the other end face, light can be collected and emitted on the other end face to constitute an organic electroluminescent device having high luminance. Can do.

  The aluminum electrode 64 is in contact with the two light-emitting layers 63 and 65, but functions as a cathode for both layers, and the characteristics of aluminum having a small work function are effective for both layers. It is alive.

  Here, an example in which an anode made of ITO and a cathode made of aluminum are provided is shown, but the present invention is not limited to this. In general, according to the structure of the organic electroluminescent device of the present embodiment, the anode and the cathode can be formed using an electrode material having an appropriate work function in accordance with the characteristics of the light emitting layers 63 and 65. Therefore, the performance of the light emitting layers 63 and 65 can be sufficiently exhibited. As a result, the luminance can be improved by stacking the organic EL elements.

  On the other hand, in the organic electroluminescence element based on the organic semiconductor element disclosed in Patent Document 2, as described above, the conductive thin film layer 124 is in contact with the one functional organic thin film layer 123 in contact therewith. Functions as an anode and must function as a cathode for the other functional organic thin film layer 123. For this reason, it is very difficult to select an appropriate material for the conductive thin film layer 124 for both of the two functional organic thin film layers 123 in contact therewith. As a result, the performance of each functional organic thin film layer 123 cannot be sufficiently exhibited, and the effect obtained by stacking is small. In this respect, the organic electroluminescence device of the present embodiment is essentially different from the organic semiconductor element disclosed in Patent Document 2.

  In addition, the organic electroluminescent device of the present embodiment can be a multi-color light source by mixing two emitted lights by using light emitting materials having different emission wavelength characteristics for the light emitting layers 63 and 65. Further, the light emitting layer may be three or more layers, and red (R), green (G), and blue (B) light may be emitted from each light emitting layer to form a full color light source by RGB color mixture.

Embodiment 6
In the sixth embodiment, the light transmissive first electrode, the first photoelectric conversion layer, the light transmissive second electrode, the second photoelectric conversion layer, and the method described in claim 1, The wavelength different from each other according to claim 11, wherein a third photoelectric conversion layer and the second light-transmissive electrode are additionally provided in one unit of a structural unit in which the third light-transmissive electrode is laminated. This is an example in which a photovoltaic cell in which a plurality of the light receiving layers that absorb the light is stacked is formed.

  FIG. 10 is an explanatory diagram showing the structure of a photovoltaic cell based on the sixth embodiment. In this photovoltaic cell, an organic semiconductor solar cell 81 is formed by a photoelectric conversion unit comprising an ITO electrode 72, a light receiving power generation layer 73 and an aluminum electrode 74, and a photoelectric conversion comprising an aluminum electrode 74, a light receiving power generation layer 75 and an ITO electrode 76. An organic semiconductor solar cell 82 is formed by being laminated by a unit, and a light receiving power generation layer 77 and an aluminum electrode 78 are additionally formed, and a photoelectric sensor comprising the ITO electrode 76, the light receiving power generation layer 77, and the aluminum electrode 78 is formed. An organic semiconductor solar cell 83 is provided by the conversion unit. The light-receiving power generation layers 73, 75, and 77 are made to have different light absorption characteristics by selecting a polymer having a π-electron conjugated system that absorbs light or a dye-containing polymer.

  If it does in this way, the light of the wavelength which was not able to be absorbed in the preceding light reception power generation layer can be absorbed in the latter light reception power generation layer, the light absorption rate can be raised, and the photoelectric conversion efficiency can be raised. In order to photoelectrically convert light in a wide wavelength range with high conversion efficiency, the wavelengths absorbed by the respective light receiving power generation layers are different from each other. It is desirable to absorb.

  For example, the light receiving power generation layer 77 absorbs light near blue, the light receiving power generation layer 75 absorbs light near green, the light receiving power generation layer 73 absorbs light near red, and so on.

Embodiment 7
In the seventh embodiment, the light transmissive first electrode, the first photoelectric conversion layer, the light transmissive second electrode, the second photoelectric conversion layer, and This is an example in which a photovoltaic cell configured to have a color filter function is formed by a dye introduced into the light receiving layer according to claim 12 in a structural unit in which a light transmissive third electrode is laminated.

  As shown in FIGS. 11A and 11B, the photovoltaic cell of the present embodiment includes a transparent substrate 91, an ITO electrode 92, a light receiving power generation layer 93, an aluminum electrode 94, a light receiving power generation layer 95, and an ITO electrode 96. The shape of the light incident surface is, for example, a square.

  When different dyes are introduced into the light receiving power generation layer 93 and the light receiving power generation layer 95 of the photovoltaic cell, various halftone colors can be formed by changing the ratio. For example, when a yellow dye is introduced into the light receiving power generation layer 93 and a red dye is introduced into the light receiving power generation layer 95, various ratios such as yellow to orange to red orange to red are obtained by changing the ratio. A color can be formed. If such a color panel is laid like a tile, a full color image can be expressed. On the other hand, in the conventional photovoltaic cell having only one conventional light receiving power generation layer, such an effect cannot be expected.

  As mentioned above, although this invention was demonstrated based on embodiment, it cannot be overemphasized that this invention is not limited to these examples at all, and can be suitably changed in the range which does not deviate from the main point of invention.

  For example, the parallel connection described in the first to third embodiments and the series connection described in the fourth embodiment can be mixed and used together.

  The photoelectric conversion device of the present invention is applied to a solar cell that converts light energy of sunlight into electric energy, an organic EL element that generates light by converting electric energy into light energy, etc. It can contribute to performance improvement such as functionalization.

They are the perspective view (a) and sectional drawing (b) which show the structure of the photovoltaic cell based on Embodiment 1 of this invention, and an equivalent circuit schematic (c). It is explanatory drawing which shows the molecular structure of MEH-PPV and PCBM which form the light reception electric power generation layer 3 equally. It is a perspective view which shows the modification of a photovoltaic cell similarly. It is a perspective view which shows the other modification of a photovoltaic cell equally. It is a perspective view which shows the further another modification of a photovoltaic cell. It is sectional drawing (a) which shows the structure of the photovoltaic cell based on Embodiment 2 of this invention, and an equivalent circuit schematic. It is sectional drawing (a) which shows the structure of the photovoltaic cell based on Embodiment 3 of this invention, and an equivalent circuit schematic. It is sectional drawing (a) which shows the structure of the photovoltaic cell based on Embodiment 4 of this invention, and an equivalent circuit schematic. It is sectional drawing (a) which shows the structure of the organic electroluminescent apparatus based on Embodiment 5 of this invention, and an equivalent circuit schematic. It is sectional drawing which shows the structure of the photovoltaic cell based on Embodiment 6 of this invention. It is explanatory drawing which shows the structure of the photovoltaic cell based on Embodiment 7 of this invention. It is sectional drawing (a) which shows the structure of a general organic-semiconductor solar cell, and its equivalent circuit (b). It is sectional drawing which shows the structure of the photoelectric conversion element currently disclosed by patent document 1. FIG. It is sectional drawing which shows the structure of the organic-semiconductor element currently disclosed by patent document 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Transparent substrate, 2, 6 ... ITO electrode, 3, 5 ... Light receiving power generation layer, 4 ... Aluminum electrode,
7, 8 ... Organic semiconductor solar cell, 9 ... External load, 11 ... Light reflecting layer, 12, 13 ... Metal electrode,
14 ... Metal oxide electrode (such as zinc oxide ZnO),
21, 29 ... 1st electrode (ITO electrode etc.), 22, 28 ... 1st photoelectric conversion layer (light receiving power generation layer), 23, 27 ... 2nd electrode (aluminum electrode etc.),
24, 26 ... 2nd photoelectric conversion layer (light receiving power generation layer), 25 ... 3rd electrode (ITO electrode etc.),
31, 34 ... first photoelectric conversion unit, 32, 33 ... second photoelectric conversion unit,
35, 36 ... external load, 41 ... first electrode (ITO electrode etc.),
42 ... 1st photoelectric conversion layer (light reception electric power generation layer), 43 ... 2nd electrode (aluminum electrode etc.),
44 ... 2nd photoelectric conversion layer (light reception electric power generation layer), 45 ... 3rd electrode (ITO electrode etc.),
46 ... insulating layer, 47 ... first photoelectric conversion unit, 48 ... second photoelectric conversion unit,
49, 50 ... external load, 51 ... first electrode (ITO electrode, etc.), 54 ... photoelectric conversion unit,
55 ... External load, 61 ... Transparent substrate, 62, 66 ... ITO electrode, 63, 65 ... Light emitting layer,
64 ... Aluminum electrode, 67, 68 ... Organic EL element, 69 ... External power supply,
71 ... Transparent substrate, 72, 76 ... ITO electrode, 73, 75, 77 ... Light receiving power generation layer,
74, 78 ... Aluminum electrode, 101 ... Transparent substrate, 102 ... Transparent electrode,
103 ... Photoelectric conversion layer (organic semiconductor polymer layer), 104 ... Counter electrode, 105 ... External load,
110a, 110b ... photovoltaic cells, 111a, 111b ... semiconductor electrodes,
112a, 112b ... electrolyte layer, 113 ... counter electrode, 114a, 114b ... diode,
115a, 115b ... transparent conductive layer, 116a, 116b ... transparent substrate,
121 ... anode, 122 ... cathode, 123 ... functional organic thin film layer, 124 ... conductor thin film layer

Claims (16)

  A photoelectric conversion device having a solid photoelectric conversion layer, wherein the light transmissive first electrode, the first photoelectric conversion layer, the light transmissive second electrode, the second photoelectric conversion layer, and the light transmissive Photoelectric conversion, in which a third electrode is stacked as a structural unit, and among the electrodes including the first electrode, the second electrode, and the third electrode, predetermined electrodes are connected in parallel apparatus.   Lamination of a structure in which the first electrode, the first photoelectric conversion layer, the second electrode, the second photoelectric conversion layer, and the third electrode are laminated in this order, and a structure in which the reverse order is laminated The photoelectric conversion device according to claim 1, having a body.   The photoelectric conversion device according to claim 2, wherein the first electrode, the second electrode, and the third electrode are connected in parallel.   A stack in which a plurality of structures in which the first electrode, the first photoelectric conversion layer, the second electrode, the second photoelectric conversion layer, and the third electrode are stacked in this order are stacked; The photoelectric conversion device according to claim 1, wherein the plurality of structures are insulated.   The photoelectric conversion device according to claim 4, wherein the first electrode, the second electrode, and the third electrode are connected in parallel.   The first photoelectric conversion layer, the second photoelectric conversion layer, the first electrode, and the third electrode are made of the same material, and the first electrode and the third electrode are connected to each other. 1. The photoelectric conversion device described in 1.   A photoelectric conversion device having a solid photoelectric conversion layer, in which a light transmissive first electrode, the photoelectric conversion layer, and a light transmissive second electrode are stacked in this order as a structural unit A photoelectric conversion device having a plurality of the structural units stacked and connected in series in the stacking direction of the stacked body.   The photoelectric conversion device according to claim 1, wherein the first and second photoelectric conversion layers are light receiving layers made of an organic semiconductor layer and configured as a photovoltaic cell.   The photoelectric conversion device according to claim 8, wherein a light reflection layer is provided on an end surface opposite to the light incident side.   The photoelectric conversion device according to claim 8, wherein the organic semiconductor layer is made of a mixture in which a photoelectron donor and an acceptor are joined.   The photoelectric conversion device according to claim 10, wherein a bulk heterojunction is formed between the donor and the acceptor in the organic semiconductor layer.   The photoelectric conversion device according to claim 8, wherein a plurality of the light receiving layers that absorb light having different wavelengths are stacked.   The photoelectric conversion device according to claim 8, wherein the photoelectric conversion device is configured to have a color filter function by a dye introduced into the light receiving layer.   The photoelectric conversion device according to claim 1, wherein each of the first and second photoelectric conversion layers is a light emitting layer made of an organic semiconductor layer, and is configured as an organic electroluminescence device.   The photoelectric conversion device according to claim 14, wherein a light reflection layer is provided on one end face.   The photoelectric conversion device according to claim 14, wherein a plurality of the light-emitting layers that emit light having different wavelengths are stacked, and light having a mixed color of the plurality of light emission is emitted.

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