Light emitting / receiving element, electronic device using same, and biosensing device

Abstract

This light reception / emission element (10) comprises a positive electrode (2), a negative electrode (6), and a light reception / emission layer (4) located between the positive electrode (2) and the negative electrode (6) and made from two or more types of organic materials. The light reception / emission layer (4) contains an electron donating material and an electron accepting material that satisfy the following relationships in terms of energy level: the HOMO of the electron donating material is higher than the HOMO of the electron accepting material; and the LUMO of the electron donating material is higher than the LUMO of the electron accepting material. At least one of these materials has a smaller band gap than the maximum light-emission wavelength energy at the time of application of a voltage to the light reception / emission layer (4). The electron donating material is distributed unevenly toward the positive electrode side within the light reception / emission layer (4). A region where the normalized responsivity spectrum and the normalized light-emission spectrum of the light reception / emission element (10) overlap one another occupies at least 50% of the region of the normalized light-emission spectrum.

Description

[Technical field]

[0001] The present invention relates to a light receiving / emitting element having both a function as a light receiving element and a function as a light emitting element, and to an electronic device and a biosensing device using the same. [Background technology]

[0002] In recent years, the Internet of Things (IoT) and big data have been attracting attention, and the importance of sensing technology to acquire various data that supports them is increasing. There are various sensing technologies, but optical sensing is one of the most useful sensing technologies because it can be used for a wide variety of applications, such as changing the target sensing wavelength.

[0003] Optical sensors generally have a light-emitting element and a light-receiving element, and sense an object by irradiating the object with light from the light-emitting element and receiving the light that is transmitted through or reflected by the object with the light-receiving element. Such optical sensors can read biological information, for example, by using near-infrared light as the wavelength. Furthermore, by forming the substrate, light-emitting element, and light-receiving element mainly from organic materials, it is possible to configure a thin and flexible device (for example, see Non-Patent Document 1).

[0004] In addition, by arranging a large number of these light-emitting elements and light-receiving elements on a substrate and forming an array, it is possible to use them as an imaging device. For example, Non-Patent Document 2 discloses a flexible imaging device capable of reading biological information, in which an organic light-receiving element is arranged on a thin transistor array (TFT array) substrate. However, since this device does not incorporate a light-emitting element, a separate light source from the outside is required. In addition, Patent Document 1 discloses an integrated light-emitting and receiving device in which a plurality of light-emitting elements and a plurality of light-receiving elements are arranged independently on a substrate. In the device described in Patent Document 1, by making it an integrated light-receiving and receiving type, an external light source is not required, and a thinner and more flexible device can be configured. However, in this way, it takes a lot of time to separately fabricate a plurality of light-emitting elements and a plurality of light-receiving elements on a substrate in a large number of independent ways, and depending on the manufacturing method, there is a limit to reducing the area of ​​one element. Furthermore, since the light-emitting elements and the light-receiving elements are separately fabricated on the same substrate, the light-receiving area for sensing within the substrate is reduced, and there is a limit to high definition.

[0005] On the other hand, Patent Document 2 discloses an imaging element having both a light receiving function and a light emitting function. By using an element having both a light receiving function and a light emitting function, it is not necessary to separately manufacture a light emitting element and a light receiving element, and manufacturing becomes easier. Furthermore, as elements having such functions, elements in which rubrene and fullerene are laminated, and elements in which a triphenylamine compound and fullerene are laminated have also been proposed (for example, see Non-Patent Documents 3 and 4). Also proposed is an element in which a small amount of rubrene is added to a mixed layer of polythiophene and a fullerene derivative (for example, see Non-Patent Document 5). [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] Science Advances, 2016, Vol. 2, p. e1501856 [Non-Patent Document 2] Nature Electronics, 2020, Vol. 3, pp. 113-121 [Non-Patent Document 3] "Advanced Materials", 2007, Vol. 19, pp. 3613-3617 [Non-Patent Document 4] "Advanced Materials", 2006, Vol. 18, pp. 3033-3037 [Non-Patent Document 5] "Synthetic Metals", 2012, Vol. 162, pp. 281-284 [Patent documents]

[0007] [Patent Document 1] JP 2013-73965 A [Patent Document 2] JP 2009-81297 A Summary of the Invention [Problem to be solved by the invention]

[0008] The inventors of the present invention considered that an element having both a light receiving function and a light emitting function (hereinafter referred to as a light receiving / emitting element) would make it possible to configure a thin and flexible light sensing device without requiring an external light source, and would be applicable to a variety of uses. However, the light receiving / emitting elements proposed so far have had insufficient light receiving sensitivity to light emitted from light receiving / emitting elements of the same configuration.

[0009] The present invention has been made in consideration of the above circumstances, and aims to provide an optical element having good light receiving sensitivity to light emitted from an optical element of the same configuration, and an electronic device and a biosensing device using the same. [Means for solving the problem]

[0010] As a result of repeated investigations, the present inventors have found that the overlap between the light receiving sensitivity spectrum and the emission spectrum of the light receiving / emitting element is particularly important. That is, in order to solve the above-mentioned problems and achieve the object, the light receiving / emitting element according to the present invention includes an anode, a cathode, and an light receiving / emitting layer located between the anode and the cathode and made of two or more organic materials, the light receiving / emitting layer contains an electron donating material and an electron accepting material that satisfy the energy level relationship represented by the following formulas (1) and (2), at least one of the electron donating material and the electron accepting material is a light receiving / emitting layer material having a band gap smaller than the maximum emission wavelength energy when a voltage is applied to the light receiving / emitting layer, the electron donating material is unevenly distributed on the anode side in the light receiving / emitting layer, and the overlapping region between the normalized light receiving sensitivity spectrum and the normalized emission spectrum occupies 50% or more of the region of the normalized emission spectrum. HOMO of electron donor material>HOMO of electron acceptor material···(1) LUMO of electron donor material>LUMO of electron acceptor material···(2)

[0011] In addition, the light receiving / emitting element of the present invention is characterized in that, in the above invention, the overlapping area between the light receiving sensitivity spectrum before normalization and the normalized emission spectrum occupies 5% or more of the area of ​​the normalized emission spectrum.

[0012] In addition, the light-emitting / receiving element according to the present invention is characterized in that, in the above-mentioned invention, the electron-donating material is the light-emitting / receiving layer material having a band gap smaller than the maximum emission wavelength energy when a voltage is applied to the light-emitting / receiving layer.

[0013] Moreover, in the above-mentioned light receiving / emitting device according to the present invention, the light receiving / emitting layer has an absorbance of 0.1 or more at a maximum emission wavelength when a voltage is applied to the light receiving / emitting layer.

[0014] In addition, the light emitting / receiving device according to the present invention is the above-mentioned invention, wherein the absorption coefficient of a single film of the material of the light emitting / receiving layer at the maximum emission wavelength when a voltage is applied to the light emitting / receiving layer is 30000 cm -1 The present invention is characterized in that:

[0015] Moreover, in the above-mentioned invention, the light receiving / emitting device according to the present invention is characterized in that the light receiving / emitting layer has at least one of a light receiving portion and a light emitting portion having a domain size of 40 nm or more.

[0016] In addition, the light emitting / receiving element according to the present invention is characterized in that, in the above-mentioned invention, a maximum emission wavelength when a voltage is applied to the light emitting / receiving layer is 700 nm or more.

[0017] In addition, the light emitting / receiving device according to the present invention is characterized in that, in the above-mentioned invention, the light emitting / receiving layer contains a diketopyrrolopyrrole boron complex compound and a fullerene compound.

[0018] In addition, the light emitting / receiving device according to the present invention is characterized in that, in the above-mentioned invention, the light emitting / receiving layer contains a rubrene compound and a thiophene compound.

[0019] An electronic device according to the present invention is characterized in that it comprises a plurality of light emitting / receiving elements according to any one of the above aspects on a substrate.

[0020] In addition, in the electronic device according to the present invention, the plurality of light emitting / receiving elements have the same configuration.

[0021] In addition, an electronic device according to the present invention comprises a plurality of light-receiving and light-emitting elements according to any one of the above inventions, the plurality of light-receiving and light-emitting elements being identical in configuration to one another, and at least one first light-receiving and light-emitting element among the plurality of light-receiving and light-emitting elements emits light to irradiate an object, and a second light-receiving and light-emitting element other than the first light-receiving and light-emitting element receives light that is transmitted through or reflected by the object.

[0022] Further, an electronic device according to the present invention is characterized in that it comprises the light emitting / receiving element according to any one of the above aspects of the invention on a TFT array substrate.

[0023] A biological sensing device according to the present invention is characterized by comprising the light receiving and emitting element according to any one of the above aspects of the present invention. Effect of the Invention

[0024] According to the present invention, it is possible to provide an optical detector that is easy to manufacture and has good optical sensitivity to light emitted from optical detectors of the same configuration, and an electronic device and a biosensing device using the same. [Brief description of the drawings]

[0025] [Figure 1] FIG. 1 is a diagram showing an example of a normalized light receiving sensitivity spectrum and a normalized light emission spectrum of an optical element according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram showing an example of a light receiving sensitivity spectrum (external quantum yield spectrum) before normalization and a normalized light emission spectrum of the light receiving and light emitting element according to the embodiment of the present invention. [Diagram 3] FIG. 3 is a schematic cross-sectional view showing one aspect of the light emitting / receiving element according to the embodiment of the present invention. [Figure 4] FIG. 4 is a diagram showing an example of a pulse wave measurement result obtained by the biosensing device produced in Example 13. [Diagram 5] FIG. 5 is a diagram showing an example of a pulse wave measurement result obtained by the biosensing device produced in Example 14. [Figure 6] FIG. 6 is a diagram showing an example of a pulse wave measurement result obtained by the biosensing device produced in Comparative Example 6. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] The following is a detailed description of embodiments of the light-receiving and light-emitting element according to the present invention, and an electronic device and a biosensing device using the same, but the present invention is not limited to the following embodiments and can be modified in various ways depending on the purpose and application. It should be noted that the drawings are schematic, and the dimensional relationships between the elements, the ratios between the elements, and the like may differ from the actual ones.

[0027] (Light emitting / receiving element) The light-receiving / emitting device according to the embodiment of the present invention includes an anode and a cathode, and a light-receiving / emitting layer made of two or more organic materials between the anode and the cathode. In this light-receiving / emitting device, the light-receiving / emitting layer is a layer that exhibits a light-emitting function when a positive voltage is applied to the anode, and exhibits a light-receiving function when a zero or negative voltage is applied to the anode. In addition, it is preferable that at least one of the anode and the cathode is optically transparent.

[0028] The light receiving / emitting element according to the embodiment of the present invention satisfies the condition that "the overlapping area between the normalized light receiving sensitivity spectrum and the normalized emission spectrum (hereinafter, appropriately abbreviated as overlapping area) occupies 50% or more of the area of ​​the normalized emission spectrum." FIG. 1 is a diagram showing an example of the normalized light receiving sensitivity spectrum and the normalized emission spectrum of the light receiving / emitting element according to the embodiment of the present invention. For example, as shown in FIG. 1, the normalized light receiving sensitivity spectrum 101 is partially overlapped with the normalized emission spectrum 102. The overlapping area 103 between the normalized light receiving sensitivity spectrum 101 and the normalized emission spectrum 102 occupies 50% or more of the area of ​​the normalized emission spectrum 102. In other words, the ratio of the overlapping area 103 to the entire area of ​​the normalized emission spectrum 102 is 50% or more. By setting the overlap between the two spectra in this way, the light receiving / emitting element can achieve high light receiving sensitivity to light emitted from a light receiving / emitting element having the same configuration as the light receiving / emitting element.

[0029] In the present invention, the photosensitivity spectrum is a spectrum showing the photoelectric conversion response in terms of external quantum yield when the light receiving / emitting element is irradiated with light of each wavelength. The normalized photosensitivity spectrum is the photosensitivity spectrum normalized by a method described below. The normalized emission spectrum is the emission spectrum of the light receiving / emitting element normalized by a method described below. In addition, in FIG. 1, the normalized photosensitivity is the normalized value of the photosensitivity indicated by the normalized photosensitivity spectrum. The normalized emission intensity is the normalized value of the emission intensity indicated by the normalized emission spectrum.

[0030] Further, it is more preferable that the light receiving / emitting element according to the embodiment of the present invention satisfies the condition that "the overlapping area between the light receiving sensitivity spectrum before normalization and the normalized emission spectrum occupies 5% or more of the area of ​​the normalized emission spectrum". FIG. 2 is a diagram showing an example of the light receiving sensitivity spectrum before normalization and the normalized emission spectrum of the light receiving / emitting element according to the embodiment of the present invention. For example, as shown in FIG. 2, the light receiving sensitivity spectrum 101A before normalization is in a state where it is partially overlapped with the normalized emission spectrum 102. It is preferable that the overlapping area 103A between the light receiving sensitivity spectrum 101A before normalization and the normalized emission spectrum 102 occupies 5% or more of the area of ​​the normalized emission spectrum 102. That is, the ratio of the overlapping area 103A to the entire area of ​​the normalized emission spectrum 102 is preferably 5% or more. The ratio of the overlapping area 103A is more preferably 10% or more. This can further increase the light receiving sensitivity of the light receiving / emitting element to the light emitted from the light receiving / emitting element itself. The light receiving sensitivity spectrum before normalization is the light receiving sensitivity spectrum of the light receiving / emitting element before normalization (that is, the light receiving sensitivity spectrum that has not been normalized).

[0031] The light receiving sensitivity spectrum can be measured by a spectral sensitivity measuring device. For example, the current response when monochromatic light is irradiated to the light receiving / emitting element is measured by a spectral sensitivity measuring device, and the photoelectric conversion response is converted into an external quantum yield, so that the desired light receiving sensitivity spectrum can be displayed. The light receiving sensitivity spectrum can be normalized by dividing the external quantum yield of each wavelength by the maximum value of the wavelength dependency of the external quantum yield obtained as described above. The emission spectrum can be obtained by measuring the amount of light emitted at each wavelength using a spectroradiometer. The emission spectrum can be normalized by dividing the amount of light emitted at each wavelength by the maximum value of the wavelength dependency of the amount of light emitted obtained as described above.

[0032] Furthermore, in the light receiving / emitting element according to the embodiment of the present invention, the absorbance of the light receiving / emitting element at the maximum emission wavelength when a voltage is applied to the light receiving / emitting layer is preferably 0.1 or more. By making this absorbance 0.1 or more, the light receiving sensitivity to the light emitted from the light receiving / emitting element itself can be further increased. Here, the absorbance of the light receiving / emitting element is obtained by measuring the reflection / absorption spectrum of the light receiving / emitting element. At this time, the minimum absorbance of the light receiving / emitting element measured in the wavelength range of 300 nm to 1200 nm is used as a baseline for correction, and the difference between the reflection / absorption spectrum of the light receiving / emitting element actually measured and the baseline value (minimum absorbance) is the target absorbance. The maximum emission wavelength is the wavelength at which the amount of light emitted (light emission intensity) in the emission spectrum reaches its maximum peak.

[0033] In this way, by achieving high light receiving sensitivity to light emitted from light receiving and emitting elements of the same configuration, it becomes unnecessary to manufacture separate light receiving elements and light emitting elements, and it becomes possible to realize a light receiving and emitting element that is easy to manufacture and has both a light receiving function and a light emitting function. By using such a light receiving and emitting element, it becomes possible to realize a photosensor that can enjoy the effects of the light receiving and emitting element.

[0034] In addition, in the light receiving / emitting element according to the embodiment of the present invention, the maximum emission wavelength when a voltage is applied to the light receiving / emitting layer is preferably 700 nm or more (i.e., a wavelength in the infrared wavelength region). By having a maximum emission wavelength in such an infrared wavelength region, an optical sensor to which the light receiving / emitting element is applied can operate by receiving and emitting light invisible to the human eye. In addition, the wavelength range of 700 nm to 1400 nm is a region called a biological window. The light receiving / emitting element according to the embodiment of the present invention has light receiving / emitting responsiveness in this wavelength range, and can be suitably applied to biological sensing. The sharper the shape of the emission spectrum, the greater the overlap with the light receiving sensitivity spectrum, which is easily broadened. For this reason, the half width of the emission spectrum is preferably narrower. In addition, in order to select a sensing target according to wavelength, the half width of the emission spectrum is preferably narrower. Specifically, the half width of the emission spectrum is preferably 60 nm or less.

[0035] Fig. 3 is a cross-sectional schematic diagram showing one aspect of a light-receiving / light-emitting element according to an embodiment of the present invention. As shown in Fig. 3, the light-receiving / light-emitting element 10 according to this embodiment includes an anode 2, a cathode 6, and a light-receiving / light-emitting layer 4 located between the anode 2 and the cathode 6 on a substrate 1. The light-receiving / light-emitting element 10 also includes a hole transport layer 3 located between the anode 2 and the light-receiving / light-emitting layer 4, and an electron transport layer 5 located between the cathode 6 and the light-receiving / light-emitting layer 4. For example, the light-receiving / light-emitting element 10 shown in Fig. 3 includes an anode 2, a hole transport layer 3, a light-receiving / light-emitting layer 4, an electron transport layer 5, and a cathode 6 on a substrate 1 in this order.

[0036] The light emitting / receiving device 10 is not limited to the laminated structure shown in Fig. 3. Although not particularly shown, for example, as another embodiment of the light emitting / receiving device 10, the light emitting / receiving device may have a cathode 6, an electron transport layer 5, a light emitting / receiving layer 4, a hole transport layer 3, and an anode 2 on a substrate 1 in this order.

[0037] In order for the light receiving / receiving element 10 to emit and receive light, it is preferable that either the anode 2 or the cathode 6 has optical transparency. Of these electrodes, the one having optical transparency may be the electrode on the substrate 1 side (anode 2 in FIG. 3) or the electrode on the opposite side to the substrate 1 (cathode 6 in FIG. 3).

[0038] The substrate 1 is a substrate on which an electrode material or an organic semiconductor layer can be laminated depending on the type and use. For example, a film or plate made of an inorganic or organic material by any method can be used as the substrate 1. Examples of inorganic materials constituting the substrate 1 include non-alkali glass, quartz glass, alloys such as aluminum, iron, copper, and stainless steel. Examples of organic materials constituting the substrate 1 include polyester, polycarbonate, polyolefin, polyamide, polyimide, polyphenylene sulfide, polyparaxylene polymethyl methacrylate, epoxy resin, and fluorine-based resin. In addition, when the light receiving / emitting element 10 emits or receives light from the substrate 1 side, it is preferable that the film or plate used as the substrate 1 has a light transmittance of about 80%. In addition, when a large number of light receiving / emitting elements 10 are arranged and used, it is preferable that the substrate 1 is combined with a TFT array (TFT array substrate). It is also a preferable embodiment to form a TFT array on the substrate 1.

[0039] The anode 2 and the cathode 6 (hereinafter, these are collectively referred to as "electrodes") are made of a conductive material. For example, as the material of the electrodes, in addition to metals such as gold, platinum, silver, copper, iron, zinc, tin, aluminum, indium, chromium, nickel, cobalt, scandium, vanadium, yttrium, cerium, samarium, europium, terbium, ytterbium, molybdenum, tungsten, and titanium, metal oxides, composite metal oxides (indium tin oxide (ITO), indium zinc oxide (IZO), aluminum zinc oxide (AZO), gallium zinc oxide (GZO), etc.), alkali metals, and alkaline earth metals (lithium, magnesium, sodium, potassium, calcium, strontium, barium), etc. are preferably used. Furthermore, electrodes made of alloys of these metals or laminates of these metals are also preferably used. In addition, electrodes containing graphite, graphite intercalation compounds, carbon nanotubes, graphene, polyaniline and its derivatives, and polythiophene and its derivatives are also preferably used. The electrode may be a mixed layer made of two or more materials, or may be a layer having a laminate structure in which a plurality of layers made of two or more compounds are laminated.

[0040] In addition, at least one of the anode 2 and the cathode 6 is preferably light-transmitting. In the present invention, it is sufficient that either the anode 2 or the cathode 6 is light-transmitting, but both the anode 2 and the cathode 6 may be light-transmitting. Here, "light-transmitting" means "transmitting light to such an extent that incident light reaches the light-receiving / emitting layer to generate electromotive force, and that light generated by applying a voltage to the light-receiving / emitting layer is extracted to the outside." That is, when an electrode has a light transmittance value exceeding 0%, the electrode is light-transmitting. The light-transmitting electrode preferably has a light transmittance of 60% to 100% in all wavelength regions from 400 nm to 900 nm. The thickness of the light-transmitting electrode may be a thickness that provides sufficient electrical conductivity, and is preferably 20 nm to 300 nm, depending on the material. In addition, the electrode that does not have light transparency is sufficient as long as it is electrically conductive, and the thickness is not particularly limited.

[0041] The hole transport layer 3 is not an essential component of the light emitting / receiving element of the present invention. However, by providing the hole transport layer 3, an interface state suitable for extracting or injecting carriers can be formed, and short-circuiting between electrodes can be prevented. Therefore, in the present invention, the light emitting / receiving element is preferably provided with the hole transport layer 3. For example, the light emitting / receiving element 10 shown in FIG. 3 includes the hole transport layer 3 between the anode 2 and the light emitting / receiving layer 4.

[0042] For example, the material for forming the hole transport layer 3 may be a conductive polymer such as a polythiophene polymer, a poly-p-phenylene vinylene polymer, a polyfluorene polymer, a polypyrrole polymer, a polyaniline polymer, a polyfuran polymer, a polypyridine polymer, or a polycarbazole polymer; a phthalocyanine derivative (H2Pc, CuPc, ZnPc, or the like); Low-molecular-weight organic compounds that exhibit p-type semiconductor properties, such as phosphorus derivatives, acene compounds (tetracene, pentacene, etc.), carbon compounds such as carbon nanotubes, graphene, and graphene oxide, and molybdenum oxides such as MoO3 (MoO x ), tungsten oxide such as WO3 (WO x ), nickel oxides such as NiO (NiO x ), vanadium oxides such as V2O5 (VO x ), zirconium oxide such as ZrO2 (ZrO x ), copper oxides such as CuO (CuO x ), copper iodide, ruthenium oxide such as RuO4 (RuO x ), ruthenium oxides such as Re2O7 (ReO x ) and other inorganic compounds are preferably used. In particular, polythiophene-based polymers such as polyethylenedioxythiophene (PEDOT) and PEDOT with polystyrene sulfonate (PSS), molybdenum oxide, vanadium oxide, and tungsten oxide are preferably used as materials for the hole transport layer 3. The hole transport layer 3 may be a layer made of a single compound, a mixed layer made of two or more compounds, or a layer with a laminate structure in which multiple layers made of two or more compounds are laminated.

[0043] When a configuration in which the anode 2 adjacent to the hole transport layer 3 has optical transparency is applied to the light receiving / emitting element 10, the hole transport layer 3 preferably has high optical transparency to the emission wavelength when a voltage is applied to the light receiving / emitting element 10 (specifically, the light receiving / emitting layer 4). That is, in this case, it is more preferable that the material of the hole transport layer 3 is a material that does not have optical absorption ability for the above-mentioned emission wavelength. In addition, the thickness of the hole transport layer 3 is not particularly limited, but is preferably 5 nm or more and 600 nm or less, and more preferably 10 nm or more and 200 nm or less.

[0044] The light-receiving / emitting layer 4 is formed between the anode 2 and the cathode 6. For example, in the light-receiving / emitting device 10 shown in FIG. 3, the light-receiving / emitting layer 4 is formed between the hole transport layer 3 on the anode 2 side and the electron transport layer 5 on the cathode 6 side. A voltage is applied to the light-receiving / emitting layer 4 by applying a positive voltage to the anode 2. The light-receiving / emitting layer 4 is a layer that exhibits a light-emitting function when a positive voltage is applied in this manner, and exhibits a light-receiving function when a zero or negative voltage is applied to the anode 2.

[0045] The light-receiving and light-emitting layer 4 has the above-mentioned light-emitting and light-receiving functions, and is made of two or more organic materials. Organic materials refer to polymeric and low-molecular-weight materials, and also include complexes that contain metal atoms as part of their chemical structure. The light-receiving and light-emitting layer 4 also contains an electron-donating material and an electron-accepting material. The inclusion of these materials in the light-receiving and light-emitting layer 4 promotes charge separation when the light-receiving and light-emitting layer 4 receives light, and the light-receiving sensitivity of the light-receiving and light-emitting layer 4 can be increased. These electron-donating and electron-accepting materials satisfy the energy level relationships represented by the following formulas (1) and (2). HOMO of electron donor material>HOMO of electron acceptor material···(1) LUMO of electron donor material>LUMO of electron acceptor material···(2) In formula (1) and formula (2), HOMO is the energy level of the highest occupied molecular orbital, and LUMO is the energy level of the lowest unoccupied molecular orbital.

[0046] Moreover, it is preferable that the energy level difference between the electron donor material and the electron acceptor material satisfies the following formulas (3) and (4). HOMO of electron donor material - HOMO of electron acceptor material>0.5 eV (3) LUMO of electron donor material−LUMO of electron acceptor material>0.5 eV (4) In order to obtain a high open circuit voltage, it is preferable that the energy level difference between the electron donor material and the electron acceptor material satisfies the following formula (5). HOMO of electron donor material - LUMO of electron acceptor material>1.0 eV (5)

[0047] At least one of the electron donating material and the electron accepting material contained in the light emitting and receiving layer 4 is a material (hereinafter referred to as the light emitting and receiving layer material) having a band gap smaller than the maximum light emission wavelength energy when a voltage is applied to the light emitting and receiving layer 4. When the light emitting and receiving layer 4 contains such a material, the proportion of the overlapping region between the above-mentioned normalized light receiving sensitivity spectrum and the normalized emission spectrum to the entire region of the normalized emission spectrum can be easily increased to 50% or more.

[0048] Furthermore, within the light-receiving and light-emitting layer 4, the above-mentioned electron-donating material is unevenly distributed on the anode 2 side. When the light-receiving and light-emitting layer 4 has an asymmetric configuration as described above with respect to the electron-donating material, the light-receiving and light-emitting layer 4 can improve the charge transportability and the light-receiving sensitivity, and can also improve the recombination property and the light-emitting intensity by the charge blocking. Here, "unevenly distributed on the anode side" means that the concentration is higher on the anode side than on the cathode side in the distribution in the thickness direction of the light-receiving and light-emitting layer. Specifically, the concentration (e.g., the concentration of the electron-donating material) in the region on the anode 2 side of the center position in the thickness direction of the light-receiving and light-emitting layer 4 is higher than the region on the cathode 6 side of the center position in the thickness direction of the light-receiving and light-emitting layer 4. Examples of such a configuration include a laminated structure of an electron-donating material and an electron-accepting material, and a laminated structure including a mixed layer of the electron-donating material and the electron-accepting material. Conversely, if the electron-donating material is unevenly distributed on the cathode 6 side inside the light-receiving and light-emitting layer 4, charge injection into the light-receiving and light-emitting layer 4 becomes difficult, and furthermore, the charge blocking effect cannot be obtained, resulting in a decrease in luminescence intensity. Furthermore, when attempting to use the light-receiving function, uneven distribution of the electron-donating material on the cathode 6 side also causes a decrease in light-receiving sensitivity, since electrons generated inside the light-receiving and light-emitting layer 4 are difficult to move through the electron-donating material.

[0049] Of the electron donating material and electron accepting material contained in the light emitting / receiving layer 4, the electron donating material is preferably a light emitting / receiving layer material having a band gap smaller than the maximum light emission wavelength energy when a voltage is applied to the light emitting / receiving layer 4. Organic materials tend to exhibit p-type semiconducting properties due to the influence of various external factors (oxygen, etc.), that is, they are suitable as electron donating materials. Therefore, it is easier to obtain higher light receiving sensitivity when an electron donating material is used as the light emitting / receiving layer material than when an electron accepting material is used as the light emitting / receiving layer material.

[0050] The light-receiving and light-emitting layer 4 may contain materials other than those mentioned above. The materials may form a single material layer or a mixed layer inside the light-receiving and light-emitting layer 4. An example of a single material layer or a mixed layer made of the materials is a light-emitting layer in which a host material is mixed with a light-emitting dopant material. The thickness of the light-receiving and light-emitting layer 4 is not particularly limited, but is preferably 30 nm or more and 1000 nm or less, and more preferably 40 nm or more and 1000 nm or less.

[0051] Furthermore, the light-receiving and light-emitting layer 4 preferably has at least one of a light-receiving portion and a light-emitting portion with a domain size of 40 nm or more. When the light-receiving and light-emitting layer 4 is a single-material layer, if the thickness is sufficiently smaller than the length (width or depth, etc.) in the planar direction of the light-receiving and light-emitting layer 4, the average thickness of the light-receiving and light-emitting layer 4 is the average domain size of the single-composition portion in the light-receiving and light-emitting layer 4. The reason why the above configuration enhances the light-emitting function of the light-receiving and light-emitting layer 4 is not clear, but it is thought that the light-emitting function of the light-receiving and light-emitting layer 4 is enhanced because the excitons of the light-emitting material can be trapped and non-radiative deactivation can be suppressed.

[0052] From the viewpoints of controllability of the emission wavelength and reception wavelength of the light receiving / emitting layer 4, adaptability to flexible light receiving / emitting device 10, and charge transportability, it is preferable that 90% or more of the light receiving / emitting layer 4 is an organic semiconductor.

[0053] Furthermore, the light-emitting / receiving layer 4 contains a light-emitting material in any of its layers, regardless of its configuration. The light-emitting material may form a single material layer in the light-emitting / receiving layer 4, or may form a mixed layer in which a host material is mixed with a light-emitting dopant material, as described above, in the light-emitting / receiving layer 4. If the light-emitting material corresponds to the above-mentioned electron-donating material, it may form a mixed layer with an electron-accepting material in the light-emitting / receiving layer 4. If the light-emitting material corresponds to the above-mentioned electron-accepting material, it may form a mixed layer with an electron-donating material in the light-emitting / receiving layer 4.

[0054] The material for the light receiving and emitting layer having a band gap smaller than the maximum light emission wavelength energy has an absorption coefficient of 30000 cm at the maximum light emission wavelength when a voltage is applied to the light receiving and emitting layer 4. -1 The absorption coefficient is preferably 50000 cm or more. -1 More preferably, 90,000 cm -1 That is all. By using such a material for the light receiving and emitting layers, the light receiving sensitivity of the light receiving and emitting element 10 can be further increased. The material for the light receiving and emitting layers may be a light emitting material or a material other than the light emitting material. When the material for the light receiving and emitting layers is a light emitting material, the light emitting material is preferably a material with a small Stokes shift. By using a material with a sufficiently small Stokes shift as the material for the light receiving and emitting layers, it is possible to easily provide the light receiving and emitting layer 4 with both light emitting and light receiving functions. Note that the maximum light emitting wavelength energy is the light emitting energy at the maximum light emitting wavelength, and the maximum light emitting wavelength energy is defined as E max and The maximum emission wavelength is λ max Then, using the Planck constant h and the speed of light c, do. E max =h×c / λ max

[0055] Examples of materials for forming the light emitting and receiving layer 4 include conductive polymers such as polythiophene polymers, poly-p-phenylenevinylene polymers, polyfluorene polymers, polypyrrole polymers, polyaniline polymers, polyfuran polymers, polypyridine polymers, and polycarbazole polymers; low molecular weight organic compounds exhibiting p-type semiconductor properties, such as phthalocyanine derivatives (H2Pc, CuPc, ZnPc, etc.), porphyrin derivatives, and acene compounds (tetracene, pentacene, etc.); and electron accepting organic materials ( Examples of the material include organic materials exhibiting n-type semiconductor properties such as NTCDA, PTCDA, PTCDI-CH, oxazole derivatives, triazole derivatives, phenanthroline derivatives, phosphine oxide derivatives, phosphine sulfide derivatives, quinoline derivatives, fullerene compounds, CNT, CN-PPV, IEICO, ITIC, Y6, etc., and light-emitting materials such as rubrene, quinacridone compounds, coumarin compounds, pyrromethene compounds, diketopyrrolopyrrole compounds, and diketopyrrolopyrrole boron complex compounds. The material for forming the light-receiving and light-emitting layer 4 is not limited to these examples, and may be appropriately selected and combined from organic semiconductors and light-emitting materials according to the desired light-emitting wavelength and light-receiving wavelength.

[0056] Among them, a diketopyrrolopyrrole boron complex compound has a small Stokes shift and is an effective material for imparting both light emitting and light receiving functions to the light receiving and emitting layer 4. Furthermore, since a diketopyrrolopyrrole boron complex compound has an emission wavelength of 700 nm or more, it is one of the preferable materials to be contained in the light receiving and emitting layer 4 in order to make the maximum emission wavelength 700 nm or more when a voltage is applied to the light receiving and emitting layer 4. Furthermore, in order to make the diketopyrrolopyrrole boron complex compound function as an electron donating material, a combination of a diketopyrrolopyrrole boron complex compound and a fullerene compound is also one of the preferable embodiments of the material to be contained in the light receiving and emitting layer 4.

[0057] In addition to the combination of the diketopyrrolopyrrole boron complex compound and the fullerene compound, a combination of a rubrene compound that emits light in the visible light region and a thiophene compound that has high light absorption in the visible light region is also one of the preferred embodiments of the materials contained in the light-receiving and light-emitting layer 4.

[0058] Specific examples of the structure of the diketopyrrolopyrrole boron complex compound include the following compound described in the non-patent document "SCIENTIFIC REPOTS", 2016, Vol. 6, p. 34096.

[0059] [ka]

[0060] As a specific example of a fullerene compound, 60 Fullerene, C 70 Fullerene, C 76 Fullerene, C 78 Fullerene, C 82 Fullerene, C 84 Fullerene, C 90 Fullerene, C 94 These include unsubstituted derivatives such as fullerene, [6,6]-phenyl-C61-butyric acid methyl ester ([6,6]-C61-PCBM, or

[60] PCBM), [5,6]-phenyl-C61-butyric acid methyl ester, [6,6]-phenyl-C61-butyric acid hexyl ester, [6,6]-phenyl-C61-butyric acid dodecyl ester, and phenyl-C71-butyric acid methyl ester (

[70] PCBM). 60 Fullerenes are more preferred.

[0061] Examples of the rubrene compound include unsubstituted rubrene and rubrene substituted with an alkyl group or a halogen group.

[0062] Examples of the thiophene compound include unsubstituted oligothiophenes (terthiophene, quarterthiophene, sexithiophene, octithiophene, etc.), oligothiophenes substituted with an alkyl group or a halogen group, oligothiophenes substituted with a dicyanovinylene group, and oligothiophenes substituted with an alkyl group, a halogen group, and a dicyanovinylene group. When substituted with a dicyanovinylene group, it is preferable that the dicyanovinylene group is substituted at both ends of the oligothiophene. Examples of such compounds include 3',4'-dibutyl-5,5"-bis(dicyanovinyl)-2,2'-5',2"-terthiophene (DCV3T).

[0063] The electron transport layer 5 is not an essential component of the light-emitting / receiving element of the present invention. However, by providing the electron transport layer 5, an interface state suitable for extracting or injecting carriers can be formed, and short-circuiting between electrodes can be prevented. Therefore, in the present invention, the light-emitting / receiving element is preferably provided with the electron transport layer 5. For example, the light-emitting / receiving element 10 shown in FIG. 3 includes the electron transport layer 5 between the cathode 6 and the light-emitting / receiving layer 4.

[0064] For example, as a material for forming the electron transport layer 5, an organic material exhibiting n-type semiconductor characteristics, such as the above-mentioned electron accepting organic materials (NTCDA, PTCDA, PTCDI-CH, oxazole derivatives, triazole derivatives, phenanthroline derivatives, phosphine oxide derivatives, phosphine sulfide derivatives, quinoline derivatives, fullerene compounds, CNT, CN-PPV, etc.) is preferably used. In addition, ionic compounds such as ionic substituted fluorene-based polymers (Advanced Materials, 2011, Vol. 23, pp. 4636-4643; Organic Electronics, 2009, Vol. 10, pp. 496-500) and combinations of ionic substituted fluorene-based polymers and substituted thiophene-based polymers (Journal of American Chemical Society, 2011, Vol. 133, pp. 8416-8419), and polyethylene oxide (Advanced Materials, 2007, Vol. 19, pp. 1835-1838) can also be used as materials for the electron transport layer 5.

[0065] In addition, as the material for the electron transport layer 5, a compound having an ionic group, such as an ammonium salt, an amine salt, a pyridinium salt, an imidazolium salt, a phosphonium salt, a carboxylate salt, a sulfonate salt, a phosphate salt, a sulfate ester salt, a phosphoric acid ester salt, a sulfate salt, a nitrate salt, an acetonate salt, an oxoacid salt, or a metal complex can be used.

[0066] Specifically, examples of the compound having an ionic group include ammonium chloride, ammonium acetate, ammonium phosphate, hexyltrimethylammonium bromide, tetrabutylammonium bromide, octadecyltrimethylammonium bromide, hexadecylpyridinium bromide, 1-butyl-3-methylimidazolium bromide, tributylhexadecylphosphonium bromide, zinc formate, zinc acetate, zinc propionate, zinc butyrate, zinc oxalate, sodium heptadecafluorononanoate, sodium myristate, and sodium benzoate. Examples of such an organic compound include lithium, sodium 1-hexadecanesulfonate, sodium dodecyl sulfate, sodium monododecyl phosphate, zinc acetylacetonate, ammonium chromate, ammonium metavanadate, ammonium molybdate, ammonium hexafluorozirconate, sodium tungstate, ammonium tetrachlorozincate, tetraisopropyl orthotitanate, lithium nickelate, potassium permanganate, silver-phenanthroline complex, AgTCNQ, and compounds used in the electron transport layer described in JP-A-2013-58714.

[0067] The material of the electron transport layer 5 is, for example, titanium oxide such as TiO2 (TiO x ), zinc oxide such as ZnO (ZnO x ), silicon oxides such as SiO2 (SiO x ), tin oxide such as SnO2 (SnO x ), tungsten oxide such as WO3 (WO x ), Ta2O3 and other tantalum oxides TaO x ), barium titanate such as BaTiO3 (BaTi x O y ), barium zirconate such as BaZrO3 (BaZr x O y ), zirconium oxide such as ZrO2 (ZrO x ), hafnium oxide such as HfO2 (HfO x ), aluminum oxide such as Al2O3 (A lO x ), yttrium oxide such as Y2O3 (YO x), zirconium silicate such as ZrSiO4 ZrSi x O y ), silicon nitrides such as Si3N4 (SiN x ) Nitrides such as CdS, cadmium sulfides such as CdS x ), zinc selenides such as ZnSe ( ZnSe x ), zinc sulfide such as ZnS (ZnS x ), cadmium tellurides such as CdTe (CdTe x Inorganic materials such as semiconductors such as .

[0068] Examples of methods for forming the electron transport layer 5 using the inorganic material include a method of applying a precursor solution of a metal salt or metal alkoxide of the inorganic material to a substrate and then heating to form a layer, and a method of applying a nanoparticle dispersion to a substrate to form a layer. At this time, depending on the heating temperature, heating time, and nanoparticle synthesis conditions, the reaction may not proceed completely, and may be partially hydrolyzed or partially condensed to form an intermediate product, a mixture of the precursor and the intermediate product, or a mixture of the precursor and the final product.

[0069] When a configuration in which the cathode 6 adjacent to the electron transport layer 5 has optical transparency is applied to the light receiving / emitting device 10, the electron transport layer 5 preferably has high optical transparency to the emission wavelength when a voltage is applied to the light receiving / emitting device 10 (specifically, the light receiving / emitting layer 4). That is, in this case, it is more preferable that the material of the electron transport layer 5 is a material that does not have optical absorption ability for the above-mentioned emission wavelength.

[0070] (Method of manufacturing light emitting / receiving element) Next, a method for manufacturing the light emitting / receiving element according to the embodiment of the present invention will be described with reference to the light emitting / receiving element 10 shown in FIG.

[0071] When manufacturing the light emitting / receiving element 10, first, a transparent electrode such as ITO is formed by a sputtering method or the like on the substrate 1. In this embodiment, this transparent electrode corresponds to the anode 2 shown in FIG.

[0072] Next, a mixture of PEDOT and PSS is applied onto the transparent electrode and dried, thereby forming a PEDOT:PSS layer on the transparent electrode. This PEDOT:PSS layer corresponds to the hole transport layer 3 shown in FIG. 3. Any method may be used to form the hole transport layer 3, such as spin coat application, blade coat application, slit die coat application, screen printing application, bar coater application, mold application, print transfer method, immersion pull-up method, inkjet method, spray method, vacuum deposition method, etc. The method for forming the hole transport layer 3 may be selected according to the photoelectric conversion layer characteristics to be obtained, such as film thickness control and orientation control.

[0073] Next, for example, a diketopyrrolopyrrole boron complex compound is dissolved in a solvent to prepare a solution, and the solution is applied onto the hole transport layer 3 and dried. As a result, a layer of the light-emitting portion is formed on the hole transport layer 3. At this time, the diketopyrrolopyrrole boron complex compound functions as an electron donor material and a light-emitting material. In addition, the solvent used at this time is preferably an organic solvent, and examples of the solvent include methanol, ethanol, butanol, toluene, xylene, o-chlorophenol, acetone, ethyl acetate, ethylene glycol, tetrahydrofuran, dichloromethane, chloroform, dichloroethane, chlorobenzene, dichlorobenzene, trichlorobenzene, chloronaphthalene, dimethylformamide, dimethylsulfoxide, N-methylpyrrolidone, and γ-butyrolactone. The above solvent may be a mixture of two or more of these organic solvents. The same formation method as that for the hole transport layer 3 can be used to form the layer of the light-emitting portion.

[0074] Next, a fullerene compound (e.g., C 60A layer of fullerene, i.e., a fullerene layer, is formed by vacuum deposition. This fullerene layer corresponds to the layer of the light receiving section. The light receiving and emitting layer 4 shown in FIG. 3 is composed of a mixed layer of the above-mentioned light emitting section layer (layer made of diketopyrrolopyrrole boron complex compound) and the light receiving section layer (fullerene layer), or a layer having a laminated structure in which these layers are laminated.

[0075] Next, an electron extraction layer is formed on the fullerene layer in the light-receiving and light-emitting layer 4 by vacuum deposition or sputtering. This electron extraction layer corresponds to the electron transport layer 5 shown in FIG. 3. Next, a metal electrode made of Al, Ag, or the like is formed on the electron extraction layer by vacuum deposition or sputtering. If this electron extraction layer is formed by vacuum deposition, it is preferable to continue forming this metal electrode while maintaining the vacuum. This metal electrode corresponds to the cathode 6 shown in FIG. 3.

[0076] (Application example of light emitting / receiving element) The light-receiving / emitting element of the present invention (for example, the light-receiving / emitting element 10 shown in FIG. 3) can be applied to various electronic devices and light-sensing devices that utilize light-receiving and emitting functions. For example, it is useful for electronic devices that capture biometric information such as fingerprints and veins, biosensing devices that monitor pulse waves and blood oxygen levels, optical sensors that detect changes in the shape and movement of objects, optical switches, and the like. Although not particularly shown, the electronic device includes a plurality of the light-receiving / emitting elements described above on a substrate. Alternatively, the electronic device includes the light-receiving / emitting elements described above on a TFT array substrate. The biosensing device, optical sensor, and optical switch each include the light-receiving / emitting elements described above on a substrate, in the substrate, or in a housing. When the electronic device, biosensing device, optical sensor, and optical switch each include a plurality of the light-receiving / emitting elements described above, the plurality of light-receiving / emitting elements may be light-receiving / emitting elements having the same configuration as each other, or may be light-receiving / emitting elements having different configurations.

[0077] Furthermore, when the electronic device according to the present invention includes a plurality of the above-mentioned light-receiving and light-emitting elements on or in a substrate or in a housing, it is preferable that the plurality of light-receiving and light-emitting elements are of the same configuration. In this case, at least one first light-receiving and light-emitting element among the plurality of light-receiving and light-emitting elements can emit light to irradiate an object, and a second light-receiving and light-emitting element other than the first light-receiving and light-emitting element can receive light that has passed through or been reflected by the object. In this way, an electronic device including a plurality of light-receiving and light-emitting elements of the same configuration can perform optical sensing in which "light emitted from at least one of the first light-receiving and light-emitting elements is irradiated onto an object, and the light that has passed through or been reflected by the object is received by the second light-receiving and light-emitting element (i.e., another light-receiving and light-emitting element that is not emitting light)." EXAMPLES

[0078] The present invention will be described in more detail below based on examples. Note that the present invention is not limited to the following examples. In addition, among the compounds used in the examples, those using abbreviations are defined as shown below. ITO: Indium Tin Oxide LiF: Lithium fluoride Eg: Band gap DPPcy: An example of a diketopyrrolopyrrole boron complex compound DPPcy is a compound represented by the following chemical formula: TDCV-TPA: Tris[4-(5-dicyanomethylidenemethyl-2-thienyl)phenyl]amine TDCV-TPA is a compound represented by the following chemical formula. Alq3: Tris(8-quinolinolato)aluminum 60PCBM:Phenyl C 61 Butyric acid methyl ester DCV3T: 3',4'-dibutyl-5,5"-bis(dicyanovinyl)-2,2'-5',2"-terthiophene

[0079] [ka]

[0080] DPPcy was synthesized by the method described in a non-patent document (Scientific Reports, 2016, Vol. 6, p. 34096) and a patent document (International Publication No. WO 2019 / 151121).

[0081] Example 1 In Example 1, an evaluation sample of the light emitting / receiving element was produced by the method described below, and the produced light emitting / receiving element was evaluated.

[0082] In the manufacturing method of the light-receiving element of Example 1, first, chloroform (0.2 mL) was added to a sample bottle containing DPPcy (0.2 mg), and then ultrasonically irradiated in an ultrasonic cleaner for 30 minutes to obtain solution A. In addition, a PEDOT:PSS solution (6.0 mL) and isopropyl alcohol (4.0 mL) were added to a sample bottle and stirred to obtain solution B for forming a hole transport layer. As the PEDOT:PSS solution, "CLEVIOS P VP AI4083" manufactured by HC Starck was used.

[0083] Next, a 125 nm thick ITO transparent conductive layer (hereafter referred to as ITO layer) was deposited on the glass substrate by sputtering, and the glass substrate was cut to a size of 38 mm x 46 mm, after which the ITO layer was patterned into a rectangular shape of 38 mm x 13 mm by photolithography. The glass substrate was then ultrasonically cleaned for 10 minutes with an alkaline cleaning solution (Furuuchi Chemical Co., Ltd., "Semicoclean" EL56), and then washed with ultrapure water.

[0084] Next, after the glass substrate was subjected to UV / ozone treatment for 30 minutes, the above solution B was dropped onto the ITO layer of the glass substrate, applied at 3000 rpm by spin coating, and heat-treated on a hot plate for 30 minutes at 100° C. As a result, a PEDOT:PSS layer (hole transport layer) with a thickness of about 30 nm was formed on the ITO layer.

[0085] Next, the above solution A was dropped onto the PEDOT:PSS layer and applied by spin coating. As a result, a DPPcy layer with a thickness of 8 nm was formed on the hole transport layer. Thereafter, the glass substrate on which the above DPPcy layer was formed and a deposition mask were placed in a vacuum deposition apparatus, and the degree of vacuum in the apparatus was set to 1×10 -3 The vacuum was then pumped down to a pressure of 0.01 Pa or less, and a 25 nm thick C 60 Fullerene was evaporated onto the DPPcy layer. 60 A light emitting / receiving layer having a laminated structure with a fullerene layer (hereinafter abbreviated as a C60 layer) was formed.

[0086] Next, the glass substrate on which the C60 layer had been formed was taken out into the atmosphere, and the deposition mask was replaced with an electrode deposition mask. The glass substrate and the electrode deposition mask were then placed in a vacuum deposition apparatus, and the degree of vacuum in the apparatus was adjusted to 1×10 -3 The chamber was again evacuated until the pressure reached or below Pa. Next, a LiF layer having a thickness of 0.5 nm and an aluminum layer having a thickness of 100 nm to serve as an electrode (anode) were evaporated onto the C60 layer of the glass substrate by resistance heating.

[0087] In Example 1, a light-receiving / light-emitting device was produced by the above-mentioned manufacturing method, in which the area of ​​the intersection between the striped ITO layer and the silver layer was 5 mm x 5 mm. Thereafter, the glass substrate of this light-receiving / light-emitting device was transferred to a glove box under a nitrogen atmosphere, and a photocurable resin (XNR5570 manufactured by Nagase ChemteX Corporation) was applied to a glass (gas barrier layer substrate) measuring 20 mm x 20 mm, which was then attached to the center of the above-mentioned glass substrate. Next, ultraviolet light (wavelength 365 nm, intensity 100 mWcm) was applied to the glass substrate. -2 ) for 1 minute to cure the photocurable resin.

[0088] In Example 1, the external quantum yield spectrum (light-receiving sensitivity spectrum) of the anode and cathode of the light-receiving / light-emitting element fabricated as described above was measured using a spectral sensitivity measurement device when the applied voltage was 0 V. Next, the emission spectrum was measured using a spectral irradiance measurement device when a current of 50 mA was applied to the light-receiving / light-emitting element. The obtained external quantum yield spectrum and emission spectrum were normalized by their respective maximum values, and the overlapping region (overlapping region) of these normalized spectra was estimated, and the ratio of the overlapping region to the entire region of the normalized emission spectrum was estimated. The overlapping region between the obtained external quantum yield spectrum (light-receiving sensitivity spectrum before normalization) and the normalized emission spectrum was also estimated in the same manner.

[0089] Next, a current of 50 mA was applied to the light emitting / receiving element of Example 1, and the light emitted was irradiated onto a silicon photodiode. The current value of this silicon photodiode was measured, thereby measuring the amount of light emitted by this light emitting / receiving element.

[0090] Next, a spectrophotometer was used to measure the reflection / absorption spectrum of the light receiving / emitting element of Example 1 when the element received light that was specularly reflected at an angle of 5°. The absorbance of the light receiving / emitting element was estimated by correcting the baseline by taking the difference between the reflection / absorption spectrum and the minimum value in the wavelength range of 300 nm to 1200 nm.

[0091] Next, a chloroform solution of DPPcy adjusted to a concentration of 5 g / L was applied to a glass substrate by spin coating to form a DPPcy layer with a thickness of 50 nm. 60 Fullerene was evaporated to a thickness of 50 nm to form a C60 layer. A spectrophotometer was used to obtain the transmission and absorption spectrum of each of these single material films. The absorption coefficient was estimated from the obtained transmission and absorption spectrum using the following equation. Extinction coefficient (cm -1 ) = absorbance / 0.434 / film thickness (cm -1 )

[0092] In addition, the band gap (Eg) of each of the single material films was estimated from the absorption edge wavelength of the transmission absorption spectrum by the following formula. Eg(eV)=1240 / absorption edge wavelength(nm)

[0093] Furthermore, for each of the single material films, the HOMO was measured using atmospheric photoelectron spectroscopy (RIKEN AC-2), and the LUMO was estimated using the following equation. LUMO(eV)=HOMO(eV)-Eg(eV)

[0094] Next, in Example 1, the two light-receiving and light-emitting elements prepared as described above were placed in a dark room at a distance of 5 mm apart, and the glass substrate surfaces of the ITO layers of these light-receiving and light-emitting elements were placed opposite each other. Then, a current of 50 mA was passed through one of the light-receiving and light-emitting elements to cause it to emit light, and a Keithley 2400 series source meter was connected to the other light-receiving and light-emitting element to measure the current value when the applied voltage was changed from -1 V to +1 V. In addition, the current value was measured when the applied voltage was changed from -1 V to +1 V in the dark without causing it to emit light. The light-receiving sensitivity to the light emitted from the light-receiving and light-emitting element of the same configuration was measured by subtracting the current value in the dark from the current value when the light was emitted at 0 V, and this was used as an index of the light-receiving sensitivity to the light emitted from the light-receiving and light-emitting element itself. In addition, the open circuit voltage (the voltage at which the current becomes 0) for the light emitted from the light-receiving and light-emitting element of the same configuration was read from the current-voltage characteristics measured during light emission.

[0095] Example 2 In Example 2, chloroform (0.2 mL) was added to a sample bottle containing DPPcy (0.4 mg), and the solution was subjected to ultrasonic irradiation for 30 minutes in an ultrasonic cleaner to obtain solution C. In Example 2, a light-receiving and light-emitting device was produced and measured in exactly the same manner as in Example 1, except that solution A in Example 1 was replaced with solution C and the film thickness of the DPPcy layer was set to 15 nm.

[0096] Example 3 In Example 3, chloroform (0.2 mL) was added to a sample bottle containing DPPcy (1.0 mg), and the solution was subjected to ultrasonic irradiation for 30 minutes in an ultrasonic cleaner to obtain solution D. In Example 3, a light-receiving and light-emitting device was produced and measured in the same manner as in Example 1, except that solution A in Example 1 was replaced with solution D and the film thickness of the DPPcy layer was set to 40 nm.

[0097] Example 4 In Example 4, chloroform (0.2 mL) was added to a sample bottle containing DPPcy (2.0 mg), and the solution was subjected to ultrasonic irradiation for 30 minutes in an ultrasonic cleaner to obtain solution E. In Example 4, a light-receiving and light-emitting device was produced and measured in exactly the same manner as in Example 1, except that solution A in the above-mentioned Example 1 was replaced with solution E and the film thickness of the DPPcy layer was set to 70 nm.

[0098] Example 5 In Example 5, a light emitting / receiving device was produced and measured in exactly the same manner as in Example 1, except that the thickness of the C60 layer was 40 nm.

[0099] Example 6 In Example 6, a light emitting / receiving device was produced and measured in exactly the same manner as in Example 2, except that the thickness of the C60 layer was set to 40 nm.

[0100] Example 7 In Example 7, a light emitting / receiving device was produced and measured in exactly the same manner as in Example 3, except that the thickness of the C60 layer was 40 nm.

[0101] Example 8 In Example 8, a light emitting / receiving device was produced and measured in exactly the same manner as in Example 4, except that the thickness of the C60 layer was 40 nm.

[0102] Example 9 In Example 9, a light emitting / receiving device was produced and measured in exactly the same manner as in Example 2, except that the thickness of the C60 layer was set to 75 nm.

[0103] Example 10 In Example 10, a light emitting / receiving device was produced and measured in exactly the same manner as in Example 3, except that the thickness of the C60 layer was 75 nm.

[0104] Example 11 In Example 11, a light emitting / receiving device was produced and measured in exactly the same manner as in Example 4, except that the thickness of the C60 layer was set to 75 nm.

[0105] Example 12 In Example 12, chloroform (0.2 mL) was added to a sample bottle containing 1.0 mg of rubrene, and the solution was subjected to ultrasonic irradiation for 30 minutes in an ultrasonic cleaner to obtain solution I. In Example 12, solution A in the above-mentioned Example 1 was replaced with solution I, the DPPcy layer was a rubrene layer with a thickness of 40 nm, and a DCV3T layer was formed with a thickness of 25 nm by vacuum deposition instead of the C60 layer, and other than these, a light-receiving and light-emitting device was produced and measured in the same manner as in Example 1.

[0106] Comparative Example 1 In Comparative Example 1, chloroform (0.2 mL) was added to a sample bottle containing 1.0 mg of rubrene (manufactured by Tokyo Chemical Industry Co., Ltd.), and the solution was subjected to ultrasonic irradiation for 30 minutes in an ultrasonic cleaner to obtain solution F. In Comparative Example 1, a light-receiving and light-emitting element was produced and measured in exactly the same manner as in Example 1, except that solution A in the above-mentioned Example 1 was replaced with solution F and a rubrene layer with a film thickness of 40 nm was formed.

[0107] Comparative Example 2 In Comparative Example 2, chloroform (0.2 mL) was added to a sample bottle containing 1.0 mg of TDCV-TPA (manufactured by Aldrich), and the bottle was subjected to ultrasonic irradiation for 30 minutes in an ultrasonic cleaner to obtain solution G. In Comparative Example 2, a light-receiving and light-emitting element was produced and measured in exactly the same manner as in Example 1, except that solution A in Example 1 was replaced with solution G and a TDCV-TPA layer with a thickness of 40 nm was formed.

[0108] Comparative Example 3 In Comparative Example 3, an Alq3 layer having a thickness of 40 nm was deposited on an ITO substrate, a quinacridone layer having a thickness of 40 nm was then deposited on the Alq3 layer, and an aluminum layer serving as an electrode was then deposited on the quinacridone layer to a thickness of 100 nm. In this manner, the light-receiving / emitting device of Comparative Example 3 was produced. In Comparative Example 3, the light-receiving / emitting device was measured in the same manner as in Example 1, except that the current condition for causing the light-receiving / emitting device to emit light was changed from 50 mA to 3 mA. The light-emitting condition of Comparative Example 3 was changed because the light-receiving / emitting device deteriorates and no longer emits light when a current larger than 3 mA is applied.

[0109] Comparative Example 4 In Comparative Example 4, chloroform (0.2 mL) was added to a sample bottle containing 1.0 mg of DPPcy and 1.0 mg of 60PCBM, and the sample bottle was subjected to ultrasonic irradiation for 30 minutes in an ultrasonic cleaner to obtain solution H. In Comparative Example 4, solution H was used instead of solution A in the above-mentioned Example 1 to form a uniform mixed layer (film thickness 100 nm) of DPPcy and 60PCBM. 60 A light emitting / receiving device was produced and measured in the same manner as in Example 1, except that fullerene was not vapor-deposited.

[0110] Comparative Example 5 In Comparative Example 5, ethyl acetate (0.2 mL) was added to a sample bottle containing 1.0 mg of DPPcy, and the solution was ultrasonically irradiated for 30 minutes in an ultrasonic cleaner to obtain a solution J. In Comparative Example 5, instead of the DPPcy layer in Example 1, a C60 layer having a thickness of 40 nm was formed by vacuum deposition, and instead of the C60 layer in Example 1, a DPPcy layer having a thickness of 40 nm was formed by applying solution J by spin coating. In Comparative Example 5, the light receiving and emitting device was produced and measured in the same manner as in Example 1, except for the formation of the C60 layer and the DPPcy layer. In Comparative Example 5, the light emission measurement showed no light emission, and the maximum light emission wavelength and the light emission spectrum could not be specified, so that the light absorption characteristics and light receiving and emitting characteristics could not be evaluated.

[0111] The materials and measurement results of the above-mentioned Examples 1 to 12 and Comparative Examples 1 to 5 are summarized in the following Tables 1-1 to 1-3. In Tables 1-1 and 1-2, "C60" in the "Light receiving and emitting layer material" and "Light absorption characteristics" columns is C 60 It means fullerene. In Table 1-2, "Em" in the "Emission characteristics" column means the maximum emission wavelength energy, and "Current value" means the current value of a silicon photodiode. "Absorbance" in the "Light absorption characteristics" column means the absorbance of the light receiving / emitting element at the maximum emission wavelength. "Specific material" means the light receiving / emitting layer material with Eg smaller than the maximum emission wavelength energy. "Absorption coefficient" means the single-film absorption coefficient at the maximum emission wavelength of the light receiving / emitting layer material with Eg smaller than the maximum emission wavelength energy. In Table 1-3, "Light receiving sensitivity" in the "Light receiving characteristics" column means the light receiving sensitivity (external quantum yield) of the light receiving / emitting element at the maximum emission wavelength. "Proportion of overlapping area (1)" in the "Light receiving / emitting characteristics" column means the proportion of the overlapping area between the normalized light receiving sensitivity spectrum and the normalized emission spectrum to the entire area of ​​the normalized emission spectrum. "Proportion of overlapping area (2)" means the proportion of the overlapping area between the light receiving sensitivity spectrum before normalization and the normalized emission spectrum to the entire area of ​​the normalized emission spectrum. In the "Light receiving / emitting characteristics" column, "Light receiving sensitivity" means the light receiving sensitivity to light emitted from a light receiving / emitting element of the same configuration. "Open circuit voltage" means the open circuit voltage to light emitted from a light receiving / emitting element of the same configuration.

[0112] [Table 1-1]

[0113] [Table 1-2]

[0114] [Table 1-3]

[0115] Example 13 In Example 13, two independent light receiving / emitting elements each having a size of 5 mm×5 mm were formed on the same glass substrate by the same method of manufacturing light receiving / emitting elements as in Example 7, with the distance between them being 3 mm, and a biosensing device having these two light receiving / emitting elements on the glass substrate was manufactured. In Example 13, the manufactured biosensing device was used to measure the pulse wave of a human body. In detail, first, the subject's middle finger was brought into contact with the glass substrate surface of the biosensing device. Next, of these two independent light receiving / emitting elements, a current of 50 mA was passed through one light receiving / emitting element to cause it to emit light, and a Keithley 2400 series source meter was connected to the other light receiving / emitting element, and the current value (light receiving current) when the applied voltage was set to 0 V was measured every 0.1 seconds to perform pulse wave measurement. In Example 13, for example, as shown in FIG. 4, a measurement result of the pulse wave represented by the light receiving current for each measurement time was obtained.

[0116] Example 14 In Example 14, two independent light receiving / emitting elements each having a size of 5 mm×5 mm were formed on the same glass substrate by the same method of manufacturing light receiving / emitting elements as in Example 12, with the distance between them being 3 mm, and a biosensing device having these two light receiving / emitting elements on the glass substrate was manufactured. In Example 14, the manufactured biosensing device was used to measure the pulse wave of a human body. In detail, first, the subject's middle finger was brought into contact with the glass substrate surface of the biosensing device. Next, of these two independent light receiving / emitting elements, a current of 50 mA was passed through one light receiving / emitting element to cause it to emit light, and a Keithley 2400 series source meter was connected to the other light receiving / emitting element, and the current value (light receiving current) when the applied voltage was set to 0 V was measured every 0.1 seconds to perform pulse wave measurement. In Example 14, for example, as shown in FIG. 5, a measurement result of the pulse wave represented by the light receiving current for each measurement time was obtained.

[0117] Comparative Example 6 In Comparative Example 6, two independent light receiving / emitting elements each having a size of 5 mm×5 mm were formed on the same glass substrate by the same method of manufacturing light receiving / emitting elements as in Comparative Example 1, with the distance between them being 3 mm, and a biosensing device including these two light receiving / emitting elements on the glass substrate was manufactured. In Comparative Example 6, the manufactured biosensing device was used to measure the pulse wave of a human body. In detail, first, the subject's middle finger was brought into contact with the glass substrate surface of the manufactured biosensing device. Next, of these two independent light receiving / emitting elements, a current of 50 mA was passed through one light receiving / emitting element to cause it to emit light, and a Keithley 2400 series source meter was connected to the other light receiving / emitting element, and the current value (light receiving current) when the applied voltage was set to 0 V was measured every 0.1 seconds to perform pulse wave measurement. In Comparative Example 6, as shown in FIG. 6, for example, a clear measurement result of the pulse wave could not be obtained. [Industrial Applicability]

[0118] As described above, the light-receiving element of the present invention, and the electronic device and biosensing device using the same are suitable for light-receiving elements having good light-receiving sensitivity to light emitted from light-receiving elements of the same configuration, and for electronic devices and biosensing devices using the same. [Explanation of symbols]

[0119] 1 Board 2 Anode 3. Hole transport layer 4. Light receiving and emitting layer 5 Electron transport layer 6 cathode 10 Light emitting / receiving element 101 Normalized photosensitivity spectrum 101A Photosensitivity Spectrum 102 Normalized Emission Spectrum 103, 103A overlapping area

Claims

1. An anode; A cathode; a light-receiving and light-emitting layer located between the anode and the cathode and made of two or more organic materials; Equipped with The light-receiving and light-emitting layer contains an electron-donating material and an electron-accepting material that satisfy the energy level relationship represented by the following formulas (1) and (2): at least one of the electron donor material and the electron acceptor material is a light emitting / receiving layer material having a band gap smaller than a maximum light emission wavelength energy when a voltage is applied to the light emitting / receiving layer, the electron donating material is unevenly distributed on the anode side in the light emitting and receiving layer, an overlapping area between the normalized light receiving sensitivity spectrum and the normalized emission spectrum occupies 50% or more of the area of ​​the normalized emission spectrum; A light emitting / receiving element. HOMO of electron donor material>HOMO of electron acceptor material (1) LUMO of electron donating material>LUMO of electron accepting material (2)

2. an overlapping area between the light receiving sensitivity spectrum before normalization and the normalized emission spectrum occupies 5% or more of an area of ​​the normalized emission spectrum; The light emitting / receiving device according to claim 1 .

3. the electron donating material is a material of the light emitting and receiving layer having a band gap smaller than the maximum light emission wavelength energy when a voltage is applied to the light emitting and receiving layer; The light emitting / receiving device according to claim 1 .

4. The absorbance at the maximum emission wavelength when a voltage is applied to the light emitting and receiving layer is 0.1 or more.

4. The light emitting / receiving device according to claim 1,

5. The absorption coefficient of a single film of the material of the light emitting and receiving layer at the maximum emission wavelength when a voltage is applied to the light emitting and receiving layer is 30000 cm －１ That's all.

5. The light emitting / receiving device according to claim 1,

6. the light-receiving and light-emitting layer has at least one of a light-receiving portion and a light-emitting portion having a domain size of 40 nm or more; 6. The light emitting / receiving device according to claim 1,

7. The maximum emission wavelength when a voltage is applied to the light emitting and receiving layer is 700 nm or more.

7. The light emitting / receiving device according to claim 1,

8. the light-receiving and light-emitting layer contains a diketopyrrolopyrrole boron complex compound and a fullerene compound, The light emitting / receiving device according to any one of claims 1 to 7.

9. the light emitting and receiving layer contains a rubrene compound and a thiophene compound, The light emitting / receiving device according to any one of claims 1 to 7.

10. A light emitting element according to any one of claims 1 to 9, comprising a plurality of light emitting / receiving elements on a substrate.

1. An electronic device comprising:

11. The plurality of light emitting / receiving elements are light emitting / receiving elements having the same configuration.

11. The electronic device according to claim 10.

12. A light emitting / receiving element according to any one of claims 1 to 9 is provided, The plurality of light emitting / receiving elements are light emitting / receiving elements having the same configuration, At least one first light receiving / emitting element among the plurality of light receiving / emitting elements emits light to irradiate an object, and a second light receiving / emitting element other than the first light receiving / emitting element receives light transmitted through or reflected by the object.

1. An electronic device comprising:

13. A light emitting element according to any one of claims 1 to 9 is provided on a TFT array substrate.

1. An electronic device comprising:

14. A light emitting / receiving element according to any one of claims 1 to 9, A biological sensing device comprising:

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