Organic semiconductor light-receiving device and manufacturing method for the same

Abstract

To provide an organic semiconductor light-receiving device and a manufacturing method for the same, capable of preventing the deterioration of an organic semiconductor element in a manufacturing process and increasing the performance, the reliability, and the definition.SOLUTION: An organic semiconductor light-receiving device 100 includes an organic thin film transistor 10, a trapezoidal electrode support part 18 with a flat top surface, a first substrate 100A provided at the top surface of the electrode support part and having a drain electrode extension part 14A on a main surface thereof, the drain electrode extension part corresponding to a conductive layer electrically connected to a drain electrode of the organic thin film transistor, and a sealing part that defines an internal space where the main surface of the first substrate and a main surface of a second substrate 100B face each other and the organic thin film transistor and an organic photodiode 20 are accommodated, and seals the first substrate and the second substrate together by bonding with the drain electrode extension part 14 in contact with the photodiode.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an organic semiconductor light-receiving device and a method for manufacturing the same. [Background technology]

[0002] 2. Description of the Related Art There is known an optical sensor configured by forming an organic photodiode using an organic semiconductor material and an organic thin film transistor on the same substrate.

[0003] For example, in Patent Document 1, a plurality of photodiodes, each of which uses an organic semiconductor material as an active layer, and transistors provided corresponding to each of the plurality of photodiodes are formed on the same substrate.

[0004] However, organic semiconductor materials are sensitive to heat, and heat during film formation processes and the like can cause a deterioration in the performance of photodiodes and transistors. Another problem is that damage occurs during the photolithography process of the electrode (upper electrode) on the organic semiconductor layer, making high-resolution patterning of organic semiconductor elements difficult. Organic semiconductor elements are also susceptible to deterioration due to moisture and oxygen, and require a surface coating such as a passivation film, but passivation alone is not enough to completely prevent the penetration of moisture and oxygen.

[0005] Furthermore, in photoelectric conversion elements using organic semiconductors, it is believed that employing a bulk heterojunction structure in which a donor material and an acceptor material are mixed as an active layer is promising for improving characteristics.

[0006] However, bulk heterojunction structures have the problem that damage caused by heat or organic solvents can adversely affect the regions (domains) of the donor and acceptor materials with a thickness of a few nanometers, resulting in a deterioration of device characteristics. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2023-30471 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made in view of the above-mentioned problems, and aims to provide an organic semiconductor light-receiving device that prevents deterioration of organic semiconductor elements during the manufacturing process, has high performance and reliability, and allows for high definition, and a manufacturing method thereof. [Means for solving the problem]

[0009] An organic semiconductor light-receiving device according to one embodiment of the present invention comprises: a first substrate having, on a main surface thereof, an organic thin film transistor, a plateau-shaped electrode support portion having a flat top surface, and a drain electrode extension portion which is a conductive layer provided on the top surface of the electrode support portion and electrically connected to a drain electrode of the organic thin film transistor; a second substrate which is a transparent substrate having a photodiode body portion on a main surface thereof, the photodiode body portion including a transparent electrode serving as a lower electrode and an organic semiconductor structure layer formed on the transparent electrode and made of an organic semiconductor including an active layer, corresponding to the organic thin film transistor; The main surface of the first substrate and the main surface of the second substrate face each other, and the main surface defines an internal space for accommodating the organic thin film transistor and the photodiode body, and the drain electrode extension abuts against the photodiode body to bond and seal the first substrate and the second substrate.

[0010] A method for manufacturing an organic semiconductor light-receiving device according to another embodiment of the present invention includes: forming an organic thin film transistor on a main surface of a first substrate, a plateau-shaped electrode support part having a flat top surface, and a drain electrode extension part which is a conductive layer provided on the top surface of the electrode support part and electrically connected to a drain electrode of the organic thin film transistor; a photodiode body portion is formed on a main surface of a second substrate that is a transparent substrate, the photodiode body portion being composed of a transparent electrode that is a lower electrode and an organic semiconductor structure layer that is provided on the transparent electrode and is made of an organic semiconductor including an active layer, in correspondence with the organic thin film transistor; The method includes a step of placing the main surface of the first substrate and the main surface of the second substrate opposite each other, and bonding and sealing the first substrate and the second substrate together so that the drain electrode extension abuts the photodiode body while defining an internal space that accommodates the organic thin film transistor and the photodiode body. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view schematically illustrating an organic semiconductor light-receiving device according to a first embodiment. [Figure 2] 2A to 2C are cross-sectional views schematically illustrating steps of a method for manufacturing the organic semiconductor light-receiving device according to the first embodiment. [Figure 3A] FIG. 2 is a plan view schematically showing step S1 of the manufacturing method. [Figure 3B] FIG. 10 is a plan view schematically showing step S2 of the manufacturing method. [Figure 3C] FIG. 10 is a plan view schematically showing step S3 of the manufacturing method. [Figure 3D] FIG. 10 is a plan view schematically showing step S4 of the manufacturing method. [Figure 4] 1 is a schematic cross-sectional view showing the configuration of an organic photodiode according to a first embodiment. [Figure 5] FIG. 4 is a cross-sectional view schematically showing an organic semiconductor light-receiving device according to a second embodiment. [Figure 6] 5A to 5C are cross-sectional views schematically illustrating steps of a method for manufacturing an organic semiconductor light-receiving device according to a second embodiment. [Figure 7] FIG. 10 is a schematic plan view corresponding to step S14. [Figure 8] FIG. 10 is a schematic cross-sectional view showing the configuration of an organic photodiode according to a second embodiment. [Figure 9]1 is a STEM image showing the results of element analysis of a conventional organic photodiode. [Figure 10] FIG. 2 is a diagram showing the light receiving characteristics of the organic photodiodes (EX1, EX2) of the first and second embodiments and an organic photodiode (CX) of a comparative example. [Figure 11] 11 is a diagram in which the vertical axis of the graph in FIG. 10 is expressed on a logarithmic (Log) scale. DETAILED DESCRIPTION OF THE INVENTION

[0012] In the following, preferred embodiments of the present invention will be described, but these may be modified and combined as appropriate. In the following description and accompanying drawings, substantially the same or equivalent components are designated by the same reference numerals.

[0013] [First embodiment] (1) Structure and manufacturing method of organic semiconductor photodetector 1 is a cross-sectional view schematically illustrating an organic semiconductor light-receiving device 100 according to a first embodiment. The organic semiconductor light-receiving device 100 includes at least one organic thin-film transistor 10 (first element) and at least one organic photodiode 20 (second element). Here, four organic photodiodes 20 and four organic thin-film transistors 10 corresponding to each organic photodiode 20 are arranged in a matrix, but the number and arrangement of the organic thin-film transistors 10 and organic photodiodes 20 are not limited to this. The number of organic thin-film transistors 10 and organic photodiodes 20 suitable for the application can be appropriately arranged.

[0014] More specifically, the organic thin-film transistor 10 has a gate electrode 11, a gate insulating film 12, a source electrode 13, a drain electrode 14, an organic semiconductor layer 15, and a protective film 16. The organic photodiode 20 has a transparent electrode 22 (first electrode) that is a lower electrode, an organic semiconductor structure layer 23 that is formed on the lower electrode and includes an active layer, and a second electrode 14A that is an upper electrode that is formed on the organic semiconductor structure layer 23. In the following description, the layer consisting of the transparent electrode 22 and the organic semiconductor structure layer 23 will be referred to as a photodiode body 20A.

[0015] At least one organic thin-film transistor 10 and at least one photodiode body 20A are provided on a first substrate 100A and a second substrate 100B facing the first substrate 100A, respectively. The second substrate 100B may be peeled off and removed from the organic semiconductor light-receiving device 100.

[0016] The structure of the organic semiconductor light-receiving device 100 will be described in detail below with reference to a method for manufacturing the organic semiconductor light-receiving device 100.

[0017] In this specification, "transparent" means having translucency for the light to be received. That is, it is preferable that the transparent element component has high transmittance for the wavelength of the light to be received, but for example, the transparent element component may be colored, printed, or provided with an optical filter. 2A to 2D are cross-sectional views schematically showing steps S1 to S4 of the method for manufacturing the organic semiconductor light-receiving device 100 of the first embodiment, and FIGS. 3A to 3D are schematic plan views corresponding to the respective steps.

[0018] (Step S1) At least one organic thin film transistor 10 (OTFT) is formed on a first substrate 100A, which is a substrate for the organic thin film transistor. In this embodiment, four organic thin film transistors 10 are formed. The first substrate 100A is formed using a glass substrate or a film substrate such as a resin substrate.

[0019] The cross-sectional view of step S1 in Figure 2 schematically shows a cross section of the first substrate 100A taken along line AA in Figure 3A. As shown in Figures 2 and 3A, gate electrodes 11 are patterned on one main surface of the first substrate 100A. At the same time, gate wiring 31 is formed to connect the gate electrodes 11 of the multiple organic thin-film transistors 10.

[0020] In addition, when multiple organic thin film transistors 10 are arranged in a matrix and driven by line-sequential scanning or the like, multiple gate wirings 31 are connected to the gate electrodes 11 of the multiple organic thin film transistors 10 for each row (or column) of the matrix.

[0021] The gate electrode 11 is formed of, for example, indium tin oxide (ITO), but is not limited to this. For example, conductive metal oxides such as ZnO and ITO, or conductive polymers such as polyethylenedioxythiophene (PEDOT) can also be used. Alternatively, a metal mesh film and these transparent conductive films can be combined. Metals (Al, Mo, Cu, etc.) can also be used.

[0022] The gate insulating film 12 is provided on the one main surface of the first substrate 100A to cover the gate electrode 11. The gate insulating film 12 is made of an organic insulating material. However, it may also be made of an inorganic material such as SiN or SiO2. A source electrode 13 and a drain electrode 14 are formed by patterning using photolithography on the gate insulating film 12. Aluminum (Al) is used for the source electrode 13 and the drain electrode 14, but gold (Au), ITO, or the like can also be used.

[0023] Furthermore, source wiring 32 connecting the source electrodes 13 of the plurality of organic thin-film transistors 10 is formed simultaneously with the source electrodes 13 and the drain electrodes 14. When the plurality of organic thin-film transistors 10 are arranged in a matrix and are driven by line-sequential scanning or the like, the plurality of source wirings 32 are connected to the source electrodes 13 of the plurality of organic thin-film transistors 10 for each column (or row) of the matrix.

[0024] The source electrode 13 and the drain electrode 14 may be reversed depending on the driving method, etc. In other words, it is sufficient that one is the source electrode and the other is the drain electrode.

[0025] Furthermore, the sensor electrode 33A (first sensor electrode) and the sensor wiring 34A connected to the sensor electrode 33A are also formed on the gate insulating film 12 at the same time as the source electrode 13 and the drain electrode 14. An appropriate number of the sensor electrodes 33A (first sensor electrodes) are provided at positions in the organic semiconductor light-receiving device 100 where pressure detection is performed.

[0026] Furthermore, an electrode support portion 18, which is a plateau-shaped protrusion made of a transparent insulator, is formed on the gate insulating film 12. The electrode support portion 18 has a flat top surface (upper surface), and a cross section perpendicular to the first substrate 100A that is trapezoidal, rectangular, or forward tapered (a shape that flares out from the bottom, with the lower surface being wider than the upper surface). The electrode support portion 18 is taller than the organic thin-film transistor 10. That is, the electrode support portion 18 has a flat top surface that is the highest point from the first substrate 100A.

[0027] The drain electrode 14 of the organic thin-film transistor 10 is formed to extend over the flat top surface of the electrode support portion 18, and the extended region is formed as a flat drain electrode extension portion 14A that extends over the top surface of the electrode support portion 18. The drain electrode extension portion 14A may be formed as a conductive layer electrically connected to the drain electrode 14. Each of the formation regions of the drain electrode extensions 14A corresponds to a formation region of the organic photodiode 20 of the organic semiconductor light receiving device 100. It is preferable that the top surface of the electrode support portion 18 and the drain electrode extensions 14A have substantially the same shape and size as the organic semiconductor structure layer 23.

[0028] In this embodiment, the drain electrode 14 is made of aluminum (Al), and the drain electrode extension 14A is formed as a part of the drain electrode 14.

[0029] The electrode support portion 18 is preferably formed of a transparent organic insulating film material, for example, a photosensitive resin such as an acrylic or siloxane resin, etc. The height (thickness) of the electrode support portion 18 is, for example, 1.5 μm, but is preferably 1 to 3 μm.

[0030] Next, the organic semiconductor layer 15 of the organic thin-film transistor 10 is patterned to straddle the source electrode 13 and the drain electrode 14. For example, the organic semiconductor layer 15 can be formed by inkjet printing. As a protective film 16 of the organic thin-film transistor 10, a Cytop film (fluororesin) covering the organic semiconductor layer 15 is formed by, for example, inkjet printing.

[0031] Through the above steps, a transistor substrate 10K is formed in which a plurality of organic thin film transistors 10 are formed on the first substrate 100A.

[0032] (Step S2) The cross-sectional view of step S2 in Fig. 2 schematically shows a cross section of the second substrate 100B taken along line BB in Fig. 3B. The second substrate 100B is an opposing substrate to the first substrate 100A, and is an organic photodiode substrate.

[0033] 2 and 3B, at least one photodiode body 20A is formed on a transparent substrate 21 provided on one main surface of the second substrate 100B. In this embodiment, four photodiode bodies 20A are formed corresponding to the organic thin-film transistors 10, respectively.

[0034] More specifically, the second substrate 100B is formed as a glass substrate or a flexible film substrate made of resin or the like. A transparent substrate 21 is provided on the second substrate 100B. Transparent electrodes 22, which are lower electrodes of the four photodiode bodies 20A, are formed on the transparent substrate 21, and an organic semiconductor structure layer 23 is formed on the transparent electrode 22. The organic semiconductor structure layer 23 is disposed at a position and with a size corresponding to the drain electrode extensions 14A of the first substrate 100A.

[0035] The transparent electrodes 22 are formed by patterning, for example, indium tin oxide (ITO). In this embodiment, two patterned transparent electrodes 22 are formed for each column of the four photodiode bodies 20A, and the transparent electrodes 22 are electrically connected to a common wiring 25, which is a wiring electrode common to the photodiode bodies 20A. The common wiring 25 is formed by patterning, for example, indium tin oxide (ITO), and can be formed simultaneously with the formation of the transparent electrodes 22. Here, the case of ITO has been described as the transparent electrode, but conductive metal oxides such as ZnO and ZnO, or conductive polymers such as polyethylenedioxythiophene (PEDOT) can also be used. Alternatively, a metal mesh film and these transparent electrodes (transparent conductive films) may be combined.

[0036] In addition, a sensor electrode 33B (second sensor electrode) and a sensor wiring 34B connected to the sensor electrode 33B are formed on the transparent substrate 21. The sensor electrode 33B is disposed at a position and with a size corresponding to the sensor electrode 33A (first sensor electrode). The sensor electrode 33B and the sensor wiring 34B can be formed simultaneously with the formation of the transparent electrode 22.

[0037] The organic semiconductor structure layer 23 is made of an organic semiconductor including an active layer, and a functional layer such as a carrier injection layer or a carrier blocking layer may be provided between the active layer and the transparent electrode 22 (lower electrode) and / or on the active layer.

[0038] Through the above steps, a photodiode substrate 20K is formed in which a plurality of photodiode bodies 20A are formed on the second substrate 100B.

[0039] (Step S3) The cross-sectional view of step S3 in FIG. 2 schematically shows a cross section of the first substrate 100A taken along line AA in FIG. 3C.

[0040] The pressure sensor material 35 is applied in dots onto the sensor electrode 33A of the first substrate 100A using a dispenser or screen printing. The pressure sensor material 35 is flexible and collapses to the height of the electrode support portion 18 or less when pressed. For example, a ferroelectric liquid crystal monomer may be used as the pressure sensor material 35. In this case, the monomer can be polymerized by irradiating it with ultraviolet light after forming the cell.

[0041] The pressure sensor material 35 may be any material that changes some physical value, such as electrical resistance, when the distance between the transistor substrate 10K and the photodiode substrate 20K changes. Specifically, the pressure sensor material 35 may be made of, for example, a pressure-sensitive conductive elastomer or polyvinylidene fluoride having a piezoelectric effect.

[0042] Furthermore, a sealing material 37 (main sealing material) is formed to surround the periphery of the region where the four organic thin film transistors 10 and the electrode support portion 18 (drain electrode extension portion 14A) are formed. It is preferable to use a photo-curable resin such as an ultraviolet curable resin for the sealing material 37, but it is also possible to use a combination of a thermosetting resin and a photo-curable resin. A gap control agent (GC agent) may be added to the sealing material 37 to maintain a predetermined gap between it and the second substrate 100B.

[0043] Although the pressure sensor material 35 and the sealing material 37 are applied to the transistor substrate 10K side in the above description, they may be formed on the photodiode substrate 20K side. That is, the pressure sensor material 35 and the sealing material 37 may be applied to the sensor electrode 33B and the transparent substrate 21 of the photodiode substrate 20K, respectively.

[0044] (Step S4) The cross-sectional view of step S4 in FIG. 2 schematically shows a cross section of the organic semiconductor light-receiving device 100 taken along line AA in FIG. 3C.

[0045] The photodiode substrate 20K was turned upside down, and the one main surface of the photodiode substrate 20K and the one main surface of the transistor substrate 10K were placed opposite each other. The transistor substrate 10K and the photodiode substrate 20K were then bonded together with a sealant 37 and sealed.

[0046] At this time, the drain electrode extension 14A and the organic semiconductor structure layer 23 are aligned and pressed together to seal the photodiode body 20A so that the drain electrode extension 14A abuts against the organic semiconductor structure layer 23. This allows the drain electrode extension 14A to function as a contact electrode (second electrode) for the organic semiconductor structure layer 23.

[0047] The pressure sensor material 35 is aligned between the sensor electrode 33A of the transistor substrate 10K and the sensor electrode 33B of the photodiode substrate 20K. The pressure sensor material 35 is irradiated with ultraviolet light and functions as a pressure sensor.

[0048] The sealing is performed by pressing the transistor substrate 10K and the photodiode substrate 20K together and photo-curing the sealing material 37. The sealing is preferably performed in an inert gas atmosphere such as nitrogen, or in a vacuum. The sealing material 37 provides an airtight seal while defining an internal space for accommodating at least one organic thin-film transistor 10 and at least one organic photodiode 20. Thus, the organic semiconductor light-receiving device 100 having at least one organic thin-film transistor 10 and at least one organic photodiode 20 is assembled into a cell.

[0049] Furthermore, the second substrate 100B may be peeled off from the organic semiconductor light-receiving device 100. When the first substrate 100A and the transparent substrate 21 are formed as flexible film substrates, the organic semiconductor light-receiving device 100 is configured as a flexible light-receiving device. Note that, in the case of the first substrate 100A, a transparent substrate may be provided as in the case of the second substrate 100B, and then peeled off from the organic semiconductor light-receiving device 100. In this case, when the transparent substrate on 100A is formed as a flexible film substrate, the organic semiconductor light-receiving device 100 is configured as a flexible light-receiving device.

[0050] (2) Structure of organic photodiode 4 is a schematic cross-sectional view showing the configuration of an organic photodiode 20 according to this embodiment. The organic semiconductor structure layer 23 includes a hole injection layer 231 as a carrier injection layer formed on a transparent electrode 22, and an active layer 232 formed on the hole injection layer 231.

[0051] Poly(3,4-ethylenedioxythiophene):polystyrenesulfonic acid (PEDOT:PSS) was used for the hole injection layer 231. The active layer 232 has a bulk heterojunction structure formed by mixing a donor material and an acceptor material.

[0052] More specifically, the active layer 232 uses an alkoxyphthalocyanine derivative (8OH2Pc), which is a low molecular weight material, as the donor material. Also, a fullerene derivative (PC), which is a low molecular weight material, as the acceptor material. 61BM) was used.

[0053] 4, the active layer 232 is formed in contact with the drain electrode extension 14 A. In this embodiment, the drain electrode 14 and the drain electrode extension 14 A are made of aluminum (Al).

[0054] The organic photodiode 20 of this embodiment is configured as a forward structure organic photodiode. Briefly, the organic photodiode 20 is configured as an ITO anode / PEDOT:PSS hole injection layer / 8OH2Pc·PC 61 The structure is a bulk heterojunction (BM) / / Al cathode (where " / / " indicates contact).

[0055] As described above, the drain electrode extension 14A of the organic thin-film transistor 10 formed on the transistor substrate 10K is abutted and pressed (arrow in the figure) against the organic semiconductor structure layer 23 formed on the photodiode substrate 20K to be electrically connected, and the drain electrode extension 14A functions as a contact electrode (second electrode) of the organic photodiode 20.

[0056] That is, since the electrodes are not formed on the organic semiconductor layer by a process such as photolithography, the organic semiconductor layer is prevented from being damaged by heat or organic solvents. This is particularly beneficial for bulk heterojunction structures that are easily damaged by heat or organic solvents, and prevents deterioration of characteristics. Furthermore, in the past, it was difficult to apply electrode processes such as photolithography to the manufacture of organic semiconductor elements, and it was not possible to manufacture electrodes with high-resolution patterns. However, according to this embodiment, the manufacture of organic semiconductor devices becomes easy.

[0057] (3) Operation of organic semiconductor photodetector 1, external light LI is incident from the photodiode substrate 20K side (second substrate 100B side) and is received by the organic photodiode 20. The generated photocurrent is transmitted to an external circuit (not shown) via the organic thin-film transistor 10.

[0058] In this embodiment, a plurality of organic photodiodes 20 and a plurality of organic thin film transistors 10 corresponding to the organic photodiodes 20 are arranged in a matrix.

[0059] In the case of a matrix arrangement, it is preferable to arrange a plurality of gate wirings and a plurality of data wirings connected to a plurality of organic thin-film transistors 10 and a plurality of organic photodiodes 20, respectively, orthogonally, and arrange and connect each organic thin-film transistor 10 and each organic photodiode 20 corresponding to each intersection of these wirings to drive each organic thin-film transistor 10 (active matrix drive).

[0060] As described above, according to this embodiment, when the upper electrode of the organic photodiode 20 is formed, the organic semiconductor layer is prevented from being damaged by heat or an organic solvent, and therefore deterioration of the organic semiconductor element during the manufacturing process is prevented, and an organic semiconductor light-receiving device having high performance, high reliability, and high definition, and a manufacturing method thereof can be provided.

[0061] [Second embodiment] (1) Structure and manufacturing method of organic semiconductor photodetector Fig. 5 is a cross-sectional view schematically showing an organic semiconductor light-receiving device 200 according to the second embodiment. Fig. 6 is a cross-sectional view schematically showing steps S11 to S14 of a method for manufacturing the organic semiconductor light-receiving device 200. Fig. 7 is a schematic plan view corresponding to step S14.

[0062] In the organic semiconductor light-receiving device 200 of the second embodiment, the organic photodiode 20 is configured as an organic photodiode with an inverted structure. The configuration of the organic semiconductor light-receiving device 200 will be described in detail below with reference to a manufacturing method for the organic semiconductor light-receiving device 200. Note that only steps and components different from those of the organic semiconductor light-receiving device 100 of the first embodiment will be described, and descriptions of steps and components that are the same as those of the first embodiment will be omitted.

[0063] (Step S11) In step S1 of the organic semiconductor light-receiving device 100 of the first embodiment, aluminum (Al) was used as the conductive film for the drain electrode 14 and the drain electrode extension 14A, but in this embodiment, gold (Au) is used. Note that a transparent conductive film such as ITO can also be used.

[0064] When the drain electrode extension 14A is a transparent film, an Au film may be formed as an ultra-thin film that can be regarded as a transparent conductive film. In this case, the thickness of the Au film is preferably within the range of 10-40 nm. This allows detection of light incident from the second substrate 100B side (rear side), and allows light to be received from either direction on both sides of the organic photodiode 20.

[0065] In this embodiment, hydrogenated phthalocyanine (H2Pc) was formed as a carrier blocking layer 41 (electron blocking layer) made of an organic semiconductor material on the electrode support portion 18. Here, H2Pc was formed by vacuum deposition.

[0066] (Step S12) Similar to step S2 in the first embodiment, a transparent electrode 22 made of indium tin oxide (ITO) was formed. On the transparent electrode 22, an organic semiconductor structure layer 23 corresponding to the four photodiode bodies 20A was formed.

[0067] The configuration of the organic semiconductor structure layer 23 of this embodiment is different from that of the organic semiconductor light-receiving device 100 of the first embodiment. Specifically, as the organic semiconductor structure layer 23, a PEIE (polyethyleneimine ethoxylate) layer 235 serving as a carrier injection layer (electron injection layer) is formed on the transparent electrode 22, and an active layer 232 having a bulk heterojunction structure is formed on the PEIE layer 235 (see FIG. 8).

[0068] The active layer 232 is made of 8OH2Pc as a donor material and PC as an acceptor material. 61 The point of having a bulk heterojunction structure with BM mixed in is the same as in the first embodiment. The thickness of the PEIE layer 235 is preferably about 5 to 10 nm.

[0069] (Step S13) The pressure sensor material 35 and the sealing material 37 were formed in the same manner as in step S3 of the first embodiment.

[0070] (Step S14) Similar to step S4 in the first embodiment, the photodiode substrate 20K was turned upside down, and the main surfaces of the transistor substrate 10K and the photodiode substrate 20K were placed opposite each other using a sealing material 37, and the transistor substrate 10K and the photodiode substrate 20K were bonded together and sealed.

[0071] At this time, sealing was performed by aligning and pressing the drain electrode extension 14A made of Au so that it abutted against the organic semiconductor structure layer 23. As a result, the drain electrode extension 14A functions as a contact electrode (second electrode) of the organic semiconductor structure layer 23.

[0072] 6 and 7, in the organic semiconductor light-receiving device 200 of this embodiment, a carrier-blocking layer 41 having substantially the same shape and size as the organic semiconductor structure layer 23 is provided between the organic semiconductor structure layer 23 and the drain electrode extension 14A, and the organic photodiode 20 functions as an organic photodiode with an inverted structure. Note that in the plan view of Fig. 7, the carrier-blocking layer 41 is shown hatched for ease of understanding.

[0073] To briefly describe the organic photodiode 20 of the second embodiment, the organic photodiode 20 is composed of an ITO cathode, a PEIE cathode, and an 8OH2Pc / PC 61 The structure is a bulk heterojunction (BM) / / H2Pc / Au anode (" / / " indicates contact).

[0074] (2) Structure of organic photodiode 8 is a schematic cross-sectional view showing the configuration of an organic photodiode 20 according to the second embodiment. The organic semiconductor structure layer 23 includes a PEIE layer 235 as a carrier injection layer formed on a transparent electrode 22, and an active layer 232 formed on the PEIE layer 235.

[0075] As described above, the active layer 232 has a bulk heterojunction structure. The drain electrode extension 14A is made of Au, and a carrier blocking layer 41 (H2Pc) is formed on the drain electrode extension 14A.

[0076] By bonding the transistor substrate 10K and the photodiode substrate 20K together, the carrier blocking layer 41 made of an organic semiconductor material formed on the drain electrode extension 14A comes into contact with and presses (indicated by the arrow in the figure) against the organic semiconductor structure layer 23, thereby electrically connecting the carrier blocking layer 41 and the drain electrode extension 14A to function as a contact electrode (second electrode) of the organic photodiode 20.

[0077] As described above, according to this embodiment, when forming the upper electrode on the organic semiconductor layer, the organic semiconductor layer is prevented from being damaged by heat or an organic solvent, and therefore deterioration of the organic semiconductor element during the manufacturing process is prevented, making it possible to provide an organic semiconductor light-receiving device that has high performance, high reliability, and allows for high definition, and a manufacturing method thereof.

[0078] [Evaluation of organic photodiodes] (1) Damage caused by the process Figure 9 shows a microscopic image of a conventional organic photodiode, showing the results of element analysis. Specifically, a cross section of an active layer with a bulk heterojunction structure, on which an Al film was deposited, was observed using a scanning transmission electron microscope and energy dispersive X-ray fluorescence detector (STEM-EDX, STEM: Scanning Transmission Electron Microscope, EDX: Energy Dispersive X-ray Spectrometer).

[0079] As shown in Figure 9, the O (oxygen) concentration is high in the interface region between the active layer and Al (microscope image on the left), and a small amount of Al (electrode metal) has penetrated into the active layer (microscope image on the right). Thus, when an Al film is vapor-deposited on the active layer, it is thought that the active layer is damaged, causing deterioration of the device.

[0080] (2) Characteristics of organic photodiodes Fig. 10 is a diagram showing the light receiving characteristics of the organic photodiode 20 (EX1) according to the first embodiment, the organic photodiode 20 (EX2) according to the second embodiment, and the organic photodiode (CX) of the comparative example. Fig. 11 shows the vertical axis of the graph in Fig. 10 on a logarithmic (Log) scale. Specifically, light with a wavelength of 760 nm was irradiated using a xenon lamp and a monochromator, and the output current (A) was plotted against the light intensity. The light intensity is shown as a percentage of the set output of the xenon lamp light source. When the set output of the xenon lamp light source was 100%, the incident light on each organic photodiode was 10.9 mW / cm2.

[0081] The organic photodiode (CX) of the comparative example was an organic photodiode in which an Al electrode was vapor-deposited on an active layer having a bulk heterojunction structure. The other configurations were the same as those of the organic photodiode 20 (EX1) of the first embodiment. As shown in FIG. 10, the photocurrent characteristics of the organic photodiode 20 (EX1) of the first embodiment, in which Al was used as an electrode and was in contact with the active layer 232, and the organic photodiode 20 (EX2) of the second embodiment, in which a carrier blocking layer 41 (H2Pc) was formed on an Au electrode and the carrier blocking layer 41 was in contact with the active layer 232, were almost equivalent to those of the organic photodiode (CX) of the comparative example.

[0082] Furthermore, as shown in FIG. 11, the organic photodiode 20 (EX1) of the first embodiment and the organic photodiode 20 (EX2) of the second embodiment both exhibited dark currents that were approximately one order of magnitude lower than that of the organic photodiode (CX) of the comparative example. As described above in detail, according to the above-described embodiment, when forming the upper electrode on the organic semiconductor layer, the organic semiconductor layer is prevented from being damaged by heat or an organic solvent, and therefore deterioration of the organic semiconductor element during the manufacturing process is prevented, and an organic semiconductor light-receiving device having high performance, high reliability, and capable of being made highly precise, and a manufacturing method thereof can be provided.

[0083] The present invention is not limited to the above-described embodiments, and modifications can be made without departing from the scope of the present disclosure. For example, in the above-described embodiments and modifications, an organic photodiode (OPD) is used as an example of an organic semiconductor light-receiving device, but the organic semiconductor light-receiving device to which the present disclosure can be applied is not limited to this. The present disclosure can be applied to various photoelectric conversion devices that convert received light into electricity.

[0084] For example, the present disclosure can be applied to organic solar cells (OPVs). Furthermore, as described above, when an ultra-thin film that can be considered transparent is used as the second electrode, power generation can be achieved by using light from both sides of the organic semiconductor light-receiving device, improving power generation efficiency. Alternatively, the present invention can be applied to various sensors and displays using organic thin film transistors and organic semiconductor light receiving elements, as well as active matrix type sensors and displays. Furthermore, according to the present invention, it is possible to provide a flexible organic semiconductor light receiving device, for example, a flexible wearable device, a biometric information sensor such as a heart rate monitor or a pulse oximeter, and the like. [Explanation of symbols]

[0085] 10: Organic thin film transistor 11: Gate electrode 12: Gate insulating film 13: Source electrode 14: Drain electrode 14A: Drain electrode extension 15: Organic semiconductor layer 18: Electrode support part 20: Organic photodiode 20A: Photodiode body 21: Transparent substrate 22: Transparent electrode 23: Organic semiconductor structural layer 25: Common wiring 31: Gate wiring 32: Source wiring 33A, 33B: sensor electrodes 34A, 34B: Sensor wiring 35: Pressure sensor material 37: Encapsulating material 41: Carrier blocking layer 100, 200: Organic semiconductor photodetector 100A: First board 100B: Second board 231: Hole injection layer 232:Active layer 235: PEIE layer

Claims

1. a first substrate having, on a main surface thereof, an organic thin film transistor, a plateau-shaped electrode support portion having a flat top surface, and a drain electrode extension portion which is a conductive layer provided on the top surface of the electrode support portion and electrically connected to a drain electrode of the organic thin film transistor; a second substrate which is a transparent substrate having a photodiode body portion on a main surface thereof, the photodiode body portion including a transparent electrode serving as a lower electrode corresponding to the organic thin film transistor, and an organic semiconductor structure layer which is provided on the transparent electrode and is made of an organic semiconductor including an active layer; a sealing portion, in which the main surface of the first substrate and the main surface of the second substrate face each other, the sealing portion defining an internal space for accommodating the organic thin film transistor and the photodiode body, and the drain electrode extension portion abutting against the photodiode body portion to bond and seal the first substrate and the second substrate; An organic semiconductor light-receiving device comprising:

2. 2. The organic semiconductor photodetector according to claim 1, wherein the active layer has a bulk heterojunction structure.

3. 3. The organic semiconductor light-receiving device according to claim 2, wherein the drain electrode extension and the photodiode body are in contact with each other to form a forward-structure organic photodiode.

4. 3. The organic semiconductor light-receiving device according to claim 2, wherein the drain electrode extension and the photodiode body are in contact with each other to form an inverted organic photodiode.

5. 5. The organic semiconductor light-receiving device according to claim 4, wherein the drain electrode extension comprises a conductive film and an electron blocking layer made of an organic semiconductor material formed on the conductive film.

6. The conductive film of the drain electrode extension is made of gold (Au), and the electron blocking layer is made of H ２ 6. The organic semiconductor light-receiving device according to claim 5, wherein the organic semiconductor light-receiving device is made of Pc.

7. 4. The organic semiconductor light-receiving device according to claim 3, wherein the electrode support portion is made of a transparent organic insulating film material, and the drain electrode extension portion is made of Au with a film thickness in the range of 10 to 40 nm.

8. the first substrate has a first sensor electrode, and the second substrate has a second sensor electrode corresponding to the first sensor electrode; The organic semiconductor light-receiving device according to claim 1 , further comprising a pressure sensor material provided between the first sensor electrode and the second sensor electrode.

9. a plurality of the organic thin film transistors and a plurality of the drain electrode extensions are provided on the main surface of the first substrate, and gate wiring is provided to connect gate electrodes of the plurality of the organic thin film transistors; 2. The organic semiconductor light-receiving device according to claim 1, wherein a plurality of said photodiode bodies and a wiring electrode common to said transparent electrodes of said plurality of said photodiode bodies are provided on said main surface of said second substrate.

10. a plurality of the organic thin film transistors and a plurality of the drain electrode extensions are provided in a matrix arrangement on the main surface of the first substrate; a plurality of the photodiode bodies are provided on the main surface of the second substrate in a matrix arrangement corresponding to the plurality of the organic thin film transistors; The organic semiconductor light-receiving device according to claim 1 , further comprising a plurality of gate wirings and a plurality of data wirings that are orthogonally arranged and connected to the plurality of organic thin-film transistors and the plurality of photodiode bodies, respectively.

11. forming an organic thin film transistor on a main surface of a first substrate, a plateau-shaped electrode support part having a flat top surface, and a drain electrode extension part which is a conductive layer provided on the top surface of the electrode support part and electrically connected to a drain electrode of the organic thin film transistor; a photodiode body portion is formed on a main surface of a second substrate that is a transparent substrate, the photodiode body portion being composed of a transparent electrode that is a lower electrode and an organic semiconductor structure layer that is provided on the transparent electrode and is made of an organic semiconductor including an active layer, in correspondence with the organic thin film transistor; the main surface of the first substrate and the main surface of the second substrate are placed opposite each other, and the first substrate and the second substrate are bonded and sealed together such that the drain electrode extension abuts on the photodiode body while defining an internal space for accommodating the organic thin film transistor and the photodiode body. A method for manufacturing an organic semiconductor light-receiving device.

12. The method for manufacturing an organic semiconductor light-receiving device according to claim 11 , wherein the active layer has a bulk heterojunction structure.

13. The method for manufacturing an organic semiconductor light-receiving device according to claim 12 , wherein the drain electrode extension and the photodiode body are in contact with each other to form a forward-structured organic photodiode.

14. The method for manufacturing an organic semiconductor light-receiving device according to claim 12, wherein the drain electrode extension and the photodiode body are abutted to form an inverted organic photodiode.

15. The method for manufacturing an organic semiconductor light-receiving device according to claim 14, wherein the drain electrode extension comprises a conductive film and an electron blocking layer made of an organic semiconductor material formed on the conductive film.

16. The conductive film of the drain electrode extension is made of gold (Au), and the electron blocking layer is made of H ２ The method for producing an organic semiconductor light-receiving device according to claim 15, wherein the organic semiconductor light-receiving device is made of Pc.

17. forming a first sensor electrode on the first substrate and a second sensor electrode corresponding to the first sensor electrode on the second substrate; 12. The method for manufacturing an organic semiconductor light-receiving device according to claim 11, wherein the step of bonding and sealing the first substrate and the second substrate includes the step of providing a pressure sensor material between the first sensor electrode and the second sensor electrode and curing the pressure sensor material.

Images