Element, photoelectric conversion element, imaging device, and method for manufacturing element

Abstract

The purpose of the present technology is to suitably suppress detachment of a quantum dot layer from the surface of a base layer when the quantum dot layer is provided during manufacturing an element. As a result of intensive studies, the present inventors have found that, when a quantum dot layer (11) is provided, detachment of the quantum dot layer (11) from the surface of a base layer (14) adjacent to the quantum dot layer (11) can be suitably suppressed by modifying the surface of the base layer (14) with a functional group (15) capable of coordinating with a metal ion or atom that is present on the surface of the quantum dots.

Description

Element, photoelectric conversion element, imaging device, and method for manufacturing the element

[0001] This disclosure relates to an element, a photoelectric conversion element, an imaging device, and a method for manufacturing the element. More specifically, it relates to an element having a quantum dot layer, etc.

[0002] Devices with quantum dot layers have been known for some time.

[0003] For example, Patent Document 1 below discloses a device having a quantum dot layer containing semiconductor nanoparticles to which a specific ligand is coordinated.

[0004] WO2019 / 151530 publication

[0005] When manufacturing the device, if a quantum dot layer is provided, the quantum dot layer may peel off from the interface (surface of the underlying layer) with the adjacent underlying layer.

[0006] Therefore, the objective of this technology is to effectively suppress the peeling of the quantum dot layer from the surface of the underlying layer when a quantum dot layer is provided during the manufacturing of the device.

[0007] As a result of diligent research, the present inventors have found that when providing a quantum dot layer, modifying the surface of the substrate layer adjacent to the quantum dot layer with a functional group that can coordinate to metal ions or atoms present on the surface of the quantum dots can effectively suppress the peeling of the quantum dot layer from the surface of the substrate layer.

[0008] In other words, the present technology provides an element comprising at least a quantum dot layer containing quantum dot particles to which ligands coordinate to metal ions or atoms present on the surface, and a base layer provided adjacent to the quantum dot layer, wherein the surface of the base layer adjacent to the quantum dot layer is modified with a functional group capable of coordinating to metal ions or atoms present on the surface of the quantum dot particles. In the element of the present technology, the functional group may be a substituent represented by the following formula (1): A-(L)- ・・・・・(1) A is an organometallic substituent or an organic substituent, and L is a single bond or a divalent group. In this case, A may have one or more structures selected from a carboxylic acid group, a mercapto group, and a carbazole skeleton, and A may have a mercapto group. Alternatively, A may have a carbazole skeleton represented by the following formula (2). R1 and R2 are each H, a halogen, or a monovalent group, and R1 or R2 may bond to an adjacent benzene ring to form a fused ring structure. In the element of this technology, if A has a carbazole skeleton represented by the above formula (2), the carbazole skeleton may be any of the following skeletons. In the device of this technology, if the functional group is a substituent represented by formula (1) above, the ligand may have the structure of A or a derivative of A. In the device of this technology, the base layer may be composed of an inorganic metal compound. In this case, the inorganic metal compound may consist of particles of 1 nm to 100 nm. Furthermore, the inorganic metal compound may be a nitride or an oxide. Moreover, the inorganic metal compound may be composed of an oxide of at least one element selected from Ti, Zn, Mo, In, Sn, Mg, Al, Cu, Fe, Hf, Co, and Ga, and TiO ２ Moox, In ２ O ３ ZnO, SnO ２ Ga ２ O ３ Al ２ O ３ CuO, HfO２ , Co ２ O ３ , Fe ２ O ３ It may be composed of at least one compound selected from. Further, the inorganic metal compound may be SiO ２ , Al ２ O ３ , SiN. In the element of the present technology, when the underlayer is composed of an inorganic metal compound, the functional group may be a substituent represented by the following formula (3). A-(L)-B - ・・・・・(3) A is an organometallic substituent or an organic substituent, L is a single bond or a divalent group, B contains Si or P. In the element of the present technology, the particles of the quantum dots may contain two or more elements selected from Pb, S, In, As, Sb, N, Se, Cu, Zn, Sn, Al, P, N, Ga, Cd, Zn, Te, Si, Ge, Sn, Ag. In this case, the particles of the quantum dots may be a semiconductor. Also, in the element of the present technology, the average particle diameter of the particles of the quantum dots may be 1 nm to 100 nm. In the present technology, further, a first electrode arranged in a pattern and a second electrode arranged opposite to the first electrode are provided, and an optoelectronic conversion element in which the element of the present technology is arranged between the first electrode and the second electrode is provided. Further, in the present technology, an imaging device including the optoelectronic conversion element of the present technology is provided.

[0009] Next, the present technology is a method for manufacturing an element having at least a quantum dot layer in which a ligand coordinates to metal ions or atoms present on the surface and an underlayer provided adjacent to the quantum dot layer. After performing a surface modification treatment of modifying the surface of the underlayer on the side adjacent to the quantum dot layer with a functional group capable of coordinating to metal ions or atoms present on the surface of the quantum dot, the quantum dot layer is formed on the surface of the underlayer. A method for manufacturing an element is provided.

[0010] This is an illustrative diagram showing the element of this technology. This is an illustrative diagram showing a conventional method for depositing a quantum dot layer on the surface of a substrate. This is an illustrative diagram showing a conventional method for depositing a quantum dot layer on the surface of a substrate. This is an illustrative diagram showing a conventional method for depositing a quantum dot layer on the surface of a substrate. This is an illustrative diagram showing a method for depositing a quantum dot layer on the surface of a substrate using this technology. This is an illustrative diagram showing a method for depositing a quantum dot layer on the surface of a substrate using this technology. This is an illustrative diagram showing a method for depositing a quantum dot layer on the surface of a substrate using this technology. This is a photograph of the surface of an element where the quantum dot layer has not peeled off. This is a photograph of the surface of an element where the quantum dot layer has peeled off.

[0011] Preferred embodiments of the present technology are described below. However, the embodiments shown below are merely examples of typical embodiments of the present technology, and the present technology is not limited to these preferred embodiments, but can be freely modified within the scope of the present technology.

[0012] [Element] As shown in Figure 1, the element 10 of this technology comprises at least a quantum dot layer 11 containing quantum dot particles to which ligands coordinate to metal ions or atoms present on the surface, and a base layer 14 provided adjacent to the quantum dot layer 11. In the element 10, the surface of the base layer 14 adjacent to the quantum dot layer 11 is modified with functional groups that can coordinate to metal ions or atoms present on the surface of the quantum dot particles, thereby effectively suppressing the peeling of the quantum dot layer 11 from the surface of the base layer 14. The elements constituting the element of this technology will be described in more detail below.

[0013] <Quantum Dot Layer> The quantum dot layer of the device of this technology contains at least quantum dot particles in which ligands are coordinated to metal ions or atoms present on the surface. For example, it may be an aggregate of quantum dot particles.

[0014] Here, "quantum dot" refers to a semiconductor particle containing a metallic element. In this specification, metallic elements also include metalloid elements such as Si. Furthermore, "a collection of quantum dot particles" refers to a large number (for example, 1 μm). ２It refers to a form in which 100 or more semiconductor quantum dots are arranged in close proximity to each other on all sides.

[0015] The quantum dots included in the quantum dot layer of the device of the present technology are not particularly limited, and any quantum dots can be used according to the purpose of the device to be manufactured. Examples of the metal elements constituting the semiconductor particles related to the quantum dots include, for example, general semiconductor crystals [a) Group IV semiconductors, b) Group IV-IV, III-V, or II-VI compound semiconductors, c) combinations of three or more of Group II, Group III, Group IV, Group V, and Group VI elements]. More specifically, for example, elements selected from Pb, S, In, As, Sb, N, Se, Cu, Zn, Sn, Al, P, N, Ga, Cd, Zn, Te, Si, Ge, Sn, Ag can be mentioned. These may constitute semiconductor particles using one kind of metal element, or may constitute semiconductor particles by combining two or more kinds of metal elements.

[0016] Specific examples of the compounds constituting the semiconductor particles include PbS, PbSe, InN, InAs, InSb, Si, InP, Ag2Te, Ag2Se, InGaAs, CuInS2, CuInSe2, CuInTe ２ , AgInSe ２ , AgInTe ２ , AgBiS ２ , AgBiSe ２ or AgBiTe ２ , semiconductor materials such as CuInGaSe and the like.

[0017] The quantum dots included in the quantum dot layer of the device of the present technology may be composed of, for example, one type of semiconductor material shown above, or may be composed of two or more types of semiconductor materials.

[0018] The average particle diameter of the particles of the quantum dots included in the quantum dot layer of the device of the present technology is, for example, 1 nm or more. Also, the lower limit of the average particle diameter of the particles of the quantum dots is preferably, for example, 100 nm or less, more preferably 10 nm or less. In the present specification, the average particle diameter refers to a state in which 95% or more of the particles of the quantum dots have the target particle diameter.

[0019] The particle surface of the quantum dot may be coordinated by ligands (also called ligands) for purposes such as stabilizing the particle surface or improving the dispersibility of the particles in the dispersion medium. Here, "ligand" refers to a molecule or ion that binds to a metal element or ion to form a coordinate bond. In this technology, "coordinating to the particle surface of the particle dot" means coordinating to a metal element or ion present on the particle surface of the quantum dot.

[0020] Furthermore, as will be described later, the ligands that coordinate to the particle surface of the quantum dots may be substituted with other ligands during the deposition process, depending on the purpose of the quantum dot layer to be deposited. For example, by changing the molecular weight (main chain length, etc.) by substituting ligands, the distance between quantum dot particles contained in the quantum dot layer can be adjusted, thereby controlling the electrical conductivity of the quantum dot layer. More specifically, by substituting with ligands with a smaller molecular weight (main chain length, etc.), the distance between quantum dot particles contained in the quantum dot layer becomes shorter, improving the electrical conductivity of the quantum dot layer.

[0021] Ligands that coordinate to the particle surface of quantum dots can be any compound that has a functional group in its molecule capable of coordinating to metal ions or atoms present on the surface of the quantum dot particles, and any ligand can be used depending on the quantum dot being used. Examples of functional groups that such ligands may have include carboxylic acid groups, mercapto groups, amino groups, substituents with a carbazole skeleton, etc.

[0022] In the device of this technology, the quantum dot layer is formed, for example, by coating a dispersion of quantum dot particles in a dispersion medium onto the surface of a base layer, which will be described later. In this case, polar solvents such as octane, toluene, chlorobenzene, dichlorobenzene, chloroform, methanol, ethanol, N,N-dimethylformamide, dimethyl sulfoxide, N-methylformamide, butylamine, and amines with a short number of carbon atoms can be suitably used as the dispersion medium.

[0023] In the devices of this technology, when a quantum dot layer is formed by coating, one possible method of film formation is a wet coating method. Specifically, examples of wet coating methods include spin coating; immersion coating; casting; various printing methods such as screen printing, inkjet printing, offset printing, and gravure printing; stamping; spraying; and various coating methods such as air doctor coater, blade coater, rod coater, knife coater, squeeze coater, reverse roll coater, transfer roll coater, gravure coater, kiss coater, cast coater, spray coater, slit orifice coater, and calender coater.

[0024] <Underlayment> The underlayment of the element of this technology is provided adjacent to the quantum dot layer described above. Furthermore, in the element of this technology, the surface of the underlayment adjacent to the quantum dot layer is modified with functional groups that can coordinate to metal ions or atoms present on the surface of the quantum dot particles. This allows the functional groups modifying the surface of the underlayment to coordinate bonds with the metal elements or ions present on the surface of the quantum dot particles constituting the quantum dot layer. As a result, the quantum dot layer and the surface of the underlayment are strongly bonded, and the peeling of the quantum dot layer from the surface of the underlayment can be effectively suppressed.

[0025] The functional group that modifies the surface of the underlying layer of the element of this technology adjacent to the quantum dot layer is not particularly limited as long as it can coordinate to metal ions or atoms present on the surface of the quantum dot particles. The functional group is represented, for example, by the following formula (1): A-(L)- ・・・・・(1) A is an organometallic substituent or an organic substituent, and L is a single bond or a divalent group.

[0026] Here, "organic substituent" refers to a substituent containing a carbon atom, whose structure includes a hydrocarbon group or part of a chemical structure based on it. Examples include alkyl groups, aryl groups, heteroalkyl groups, heteroaryl groups, arylalkyl groups, heteroarylalkyl groups, aryloxy groups, ether groups, ester groups, amino groups, etc. This also includes cases where these groups are substituted (e.g., halogenated, nitrated, or hydroxylated).

[0027] An "organometallic substituent" refers to an organic substituent in which a metal atom is directly bonded to a carbon atom. Examples of such metal elements include alkali metals (e.g., lithium, sodium), alkaline earth metals (e.g., calcium, magnesium), transition metals (e.g., iron, palladium), rare earth elements (e.g., lanthanum, cerium), or other metallic elements (e.g., aluminum, zinc, tin).

[0028] A "single bond" refers to a bond in which one pair of electrons are shared between two atoms. In general formula (1), if L is a single bond, general formula (1) can also be represented as "A-".

[0029] Furthermore, a "divalent group" refers to a group that has two bonding sites in its structure, each capable of bonding to other atoms, groups, or molecules. Examples of divalent groups include alkylene groups, arylene groups, heteroalkylene groups, heteroarylene groups, cycloalkylene groups, and carbonyl groups. Divalent groups can also be linear, branched, cyclic, or even conjugated.

[0030] The functional group represented by formula (1) can coordinate to metal ions or atoms present on the surface of the quantum dot particles in portion A. Examples of such A include carboxylic acid groups, mercapto groups, amino groups, and substituents having a carbazole skeleton. In this technology, among the A examples exemplified above, carboxylic acid groups, mercapto groups, and substituents having a carbazole skeleton are preferably used, and substituents having a mercapto group and carbazole skeletons are even more preferably used.

[0031] With respect to the functional group represented by formula (1) above, A may have one or more of the structures exemplified above. It should be noted that A having multiple of the aforementioned structures means that multiple of the aforementioned structures exist within A (including cases where A has multiple types of skeletons, multiple instances of one type of skeleton, or one or more instances of each of multiple types of skeletons).

[0032] The functional group that modifies the surface of the underlying layer of the element of this technology adjacent to the quantum dot layer may be one type or a combination of two or more functional groups.

[0033] In the device of this technology, when the chemical structure of the ligand that coordinates to the particle surface of the quantum dot and the chemical structure of the functional group that modifies the surface of the underlying layer adjacent to the quantum dot layer are similar, fluctuations in the energy level and optical properties of the quantum dot are suppressed before and after coordination of the quantum dot particle surface by the functional group, and the properties of the quantum dot layer become more stable. As a result, for example, when the device of this technology is used as a component of a photoelectric conversion element, it is expected that the increase in dark current will be suppressed.

[0034] More specifically, in the device of this technology, when the functional group that modifies the surface adjacent to the quantum dot layer of the underlying layer is represented by formula (1), the ligand that coordinates to the particle surface of the quantum dot has the structure of A or a derivative of A. This suppresses fluctuations in the energy level and optical properties of the quantum dot before and after coordination to the particle surface of the quantum dot by the functional group, making it easier to stabilize the properties of the quantum dot layer.

[0035] In the device of this technology, if the functional group that modifies the surface adjacent to the quantum dot layer of the underlying layer is represented by formula (1), and A has a substituent having a carbazole skeleton, the carbazole skeleton may be represented by the following formula (2).

[0036] R1 and R2 are each H, a halogen, or a monovalent group, and R1 or R2 may bond to an adjacent benzene ring to form a fused ring structure.

[0037] Here, "R1 or R2 bonds with an adjacent benzene ring to form a fused ring structure" means that R1 or R2 has additional bonding sites in addition to the bonding site shown in formula (2), and these bonding sites directly bond with an adjacent benzene ring, thereby forming a new cyclic structure. As a result, a form in which two or more rings are fused (a fused ring structure) is formed. A "fused ring structure" refers to a shape in which multiple rings are bonded together by sharing at least two or more carbon atoms. Examples of such fused ring structures include the structures of naphthalene, anthracene, and phenanthrene.

[0038] Examples of the carbazole skeleton represented by formula (2) above include the skeleton shown below.

[0039]

[0040] In this case as well, as described above, in the functional group represented by formula (1), A may have one of the carbazole skeletons, but A may have multiple of the aforementioned structures (including cases where there are multiple types of skeletons, cases where there are multiple of the same type of skeleton, and cases where there are one or more of each of the multiple types of skeletons).

[0041] The material constituting the underlying layer of the element in this technology can be any material depending on the purpose of the element. Such materials may be inorganic metal compounds or organic compounds. These materials may be used individually or in combination, as long as the surface adjacent to the quantum dot layer of the underlying layer can be modified with the aforementioned functional groups.

[0042] If the material constituting the base layer of the element of this technology is composed of an organic compound, the organic compound is not particularly limited as long as it is an organic compound that can be used as the base layer of the element. For example, compounds having amino groups, mercapto groups, carboxyl groups, or a carbazole skeleton in their structure can be suitably used. Furthermore, as polymer compounds, those having at least a polythiophene, polyaniline, polypyrrole, polybenzothiophene, polycarbazole, polyimidazole, or polycarboxylic acid skeleton can be suitably used.

[0043] If the underlying layer of the element of this technology is composed of an inorganic metal compound, the inorganic metal compound may be in the form of particles. In this case, the underlying layer can be formed by applying a dispersion of these particles in a dispersion medium to the surface of the target substrate. In this case as well, a dispersion medium capable of suitably dispersing the aforementioned quantum dot particles can be suitably used as the dispersion medium for the inorganic metal compound particles.

[0044] Furthermore, in the device of this technology, when the underlayer is formed by coating, the method for forming the quantum dot layer described above can be suitably used. Specifically, for example, a wet coating method that can be suitably used for forming the quantum dot layer can be suitably used.

[0045] When the underlying layer of the element of this technology is composed of an inorganic metal compound, the average particle size of the inorganic metal compound is, for example, 1 nm or more. Furthermore, the lower limit of the average particle size of the quantum dots is, for example, 100 nm or less, preferably 10 nm or less.

[0046] If the underlying layer of the element of this technology is composed of an inorganic metal compound, the inorganic metal compound may be a nitride or an oxide.

[0047] Furthermore, if the underlying layer of the element of this technology is composed of an inorganic metal compound, examples of such inorganic metal compounds include elements selected from Ti, Zn, Mo, In, Sn, Mg, Al, Cu, Fe, Hf, Co, and Ga. These may be a single metal element or a combination of two or more metal elements. The underlying layer may be composed of oxides of at least one of the elements exemplified above, for example. Alternatively, the underlying layer of the element of this technology may be composed of a composite oxide, for example.

[0048] Here, "complex oxide" refers to a compound formed by the bonding of two or more metal elements with oxygen. Examples include IGZO (Indium Gallium Zinc Oxide), which contains indium (In), gallium (Ga), and zinc (Zn), and YSZ (Yttria-Stabled Zirconia), which contains zirconium (Zr) and yttrium (Y).

[0049] Examples of inorganic metal compound oxides that can constitute the underlying layer of the element in this technology include TiO ２ Moox, In ２ O ３ ZnO, SnO ２ Ga ２ O ３ Al ２ O ３ CuO, HfO ２ Co ２ O ３ Fe ２ O ３ By using these, the underlying layer can be made into an insulating film. In this case, one of these compounds may be used, or two or more may be used in combination. Note that for the above MoOx, X > 0. An example of MoOx is MoO ３ These are some examples.

[0050] Furthermore, an inorganic metal compound that can constitute the underlying layer of the element of this technology is, for example, SiO ２ Al ２ O ３ SiN and other elements can be used. These compounds are mainly used as insulating materials, but by doping them with elements that have different numbers of outermost electrons, electrons and holes can be supplied to the conduction band or valence band, allowing them to exhibit semiconductor properties, and thus it is also possible to form the underlying layer as a semiconductor film. In this case, one of these compounds may be used, or two or more may be used in combination.

[0051] When the underlying layer of the element of this technology is composed of an inorganic metal compound, the functional group may be a substituent represented by the following formula (3): A-(L)-B- ・・・・・(3) A is an organometallic substituent or an organic substituent, L is a single bond or a divalent group, and B contains Si or P.

[0052] In formula (3), A and L are defined in the same way as in formula (1) described above. B is a linking group that contains Si or P in its structure and has two or more bonding sites to link the chemical structures. In the device of this technology, the functional group represented by formula (3) is bonded to the atom or ion present on the surface adjacent to the quantum dot layer of the underlying layer via B. The valency of B is not particularly limited and can take on a valency of two or more.

[0053] <Other Layers> The elements of this technology may include other layers besides those described above, as necessary, as long as they do not significantly impair the desired physical properties.

[0054] [Photoelectric Conversion Element] The element of this technology can be applied as a component of a device or apparatus that can utilize a quantum dot layer. For example, the element of this technology can be applied as a component of a photoelectric conversion element, which is a component of an imaging device equipped with an image sensor, a solar cell, a display, etc.

[0055] When the element of this technology is used in a photoelectric conversion element, the photoelectric conversion element may be configured to include, for example, a first electrode arranged in a pattern and a second electrode positioned opposite the first electrode, with the element of this technology placed between the first electrode and the second electrode.

[0056] Furthermore, the patterns of the first and second electrodes in the above configuration can be designed and adopted as any pattern to suit the intended photoelectric conversion element.

[0057] The photoelectric conversion element, including the element of the present technology described above, can be suitably applied to applications such as imaging devices, solar cells, and displays.

[0058] [Method of Manufacturing the Element] Next, the method of manufacturing the element of this technology will be explained in detail using diagrams, highlighting the differences from conventional technology.

[0059] Figures 2 to 4 are illustrative diagrams showing a conventional method for forming a quantum dot layer on the surface of a substrate. Figure 2 shows a state in which a dispersion of quantum dot particles 12 dispersed in a dispersion medium is applied to the surface of a substrate 14 by a wet coating method including spin coating. In this case, it can be confirmed that the surface of the quantum dot particles 12 is coordinated by ligand 13-1. Ligand 13-1 can suitably coordinate to the surface of the quantum dot particles 12 by having substituents listed above.

[0060] Figure 3 is an illustrative diagram showing the process of replacing ligand 13-1 on the surface of quantum dot particles 12 with ligand 13-2, which has a smaller molecular weight (shorter main chain length), in order to shorten the distance between quantum dot particles 12 and improve the electrical conductivity of the quantum dot layer. Specifically, by dropping a solution containing ligand 13-2 onto the surface of an element coated with a dispersion containing the quantum dot particles 12, ligand 13-1, which was coordinated to the surface of the quantum dot particles 12, is replaced by ligand 13-2. On the other hand, as shown in Figure 3, the quantum dot particles 12 and the surface of the underlying layer 14 are not chemically bonded.

[0061] As described above, the interaction between the quantum dot particles 12 and the surface of the underlying layer 14 is weak. Therefore, during subsequent cleaning of the device, the quantum dot particles 12 easily peel off from the surface of the underlying layer 14, as shown in Figure 4. As a result, delamination of the quantum dot layer from the surface of the underlying layer 14 may occur.

[0062] In contrast, Figures 5 to 7 are conceptual diagrams illustrating a method for forming a quantum dot layer on the surface of a substrate using this technology. Figure 5 corresponds to Figure 2, which represents a conventional method, and shows a state in which a dispersion of quantum dot particles 12 dispersed in a dispersion medium is applied to the surface of a substrate 14 by a wet coating method including spin coating. A difference from the conventional method shown in Figure 2 is that a surface modification treatment is performed on the surface of the substrate 14, which involves modifying it with functional groups 15 that can coordinate to the particle surface of the quantum dot particles 12.

[0063] Figure 6 corresponds to Figure 3, which represents a conventional method, and is an illustrative diagram of the process in which ligand 13-1 on the surface of quantum dot particles 12 is replaced with ligand 13-2, which has a shorter main chain length. In the device manufacturing method of this technology, as shown in Figure 6, functional groups 15 present on the surface of the substrate layer 14 can form coordinate bonds with metal ions or atoms on the particle surface of the quantum dot particles 12. That is, the quantum dot particles 12 are anchored to the surface of the substrate layer 14 by these coordinate bonds.

[0064] Figure 7 corresponds to Figure 4, which represents a conventional method. In the device manufacturing method of this technology, as described above, the surface of the base layer 14 is modified with functional groups 15, so that the quantum dot particles 12 are anchored to the surface of the base layer 14 by coordination bonds. As a result, even if washing or other processing is performed in the device manufacturing process thereafter, the quantum dot particles 12 are less likely to float away from the surface of the base layer 14, as shown in Figure 7. As a result, peeling of the quantum dot layer from the surface of the base layer 14 can be effectively suppressed.

[0065] Furthermore, this technology can take the following configurations: [1] An element having at least a quantum dot layer containing quantum dot particles in which ligands coordinate to metal ions or atoms present on the surface, and a base layer provided adjacent to the quantum dot layer, wherein the surface of the base layer adjacent to the quantum dot layer is modified with a functional group that can coordinate to metal ions or atoms present on the surface of the quantum dot particles. [2] The element according to [1], wherein the functional group is a substituent represented by the following formula (1): A-(L)- ・・・・・(1) A is an organometallic substituent or an organic substituent, and L is a single bond or a divalent group. [3] The element according to [2], wherein A has one or more structures selected from a carboxylic acid group, a mercapto group, and a carbazole skeleton. [4] The element according to [2] or [3], wherein A has a mercapto group. [5] The element according to [2] or [3], wherein A has a carbazole skeleton represented by the following formula (2). R1 and R2 are each H, a halogen, or a monovalent group, and R1 or R2 may bond to an adjacent benzene ring to form a fused ring structure. [6] The element according to [5], wherein the carbazole skeleton is one of the skeletons selected from the following. [7] The element according to any one of [2] to [6], wherein the ligand has the structure of A or a derivative of A. [8] The element according to any one of [1] to [7], wherein the underlayer is composed of an inorganic metal compound. [9] The element according to [8], wherein the inorganic metal compound consists of particles of 1 nm to 100 nm.

[10] The element according to [8] or [9], wherein the inorganic metal compound is a nitride or an oxide.

[11] The element according to any one of [8] to

[10] , wherein the inorganic metal compound is composed of an oxide of at least one element selected from Ti, Zn, Mo, In, Sn, Mg, Al, Cu, Fe, Hf, Co, Ga.

[12] The element according to any one of [8] to

[10] , wherein the inorganic metal compound is TiO ２ Moox, In ２ O ３ ZnO, SnO ２ Ga ２ O ３ Al ２ O ３ CuO, HfO ２ Co ２ O ３ Fe ２ O ３ The element according to

[10] or

[11] , comprising at least one compound selected from [1].

[13] The inorganic metal compound is SiO ２ Al ２ O ３

[14] The element according to any one of [8] to

[13] , selected from SiN.

[14] The element according to any one of [8] to

[13] , wherein the functional group is a substituent represented by the following formula (3): A-(L)-B- ・・・・・(3) A is an organometallic substituent or an organic substituent, L is a single bond or a divalent group, and B contains Si or P.

[15] The element according to any one of [1] to

[14] , wherein the quantum dot particles contain two or more elements selected from Pb, S, In, As, Sb, N, Se, Cu, Zn, Sn, Al, P, N, Ga, Cd, Zn, Te, Si, Ge, Sn, Ag.

[16] The element according to any one of [1] to

[15] , wherein the quantum dot particles are semiconductors.

[17] The element according to any one of [1] to

[16] , wherein the average particle size of the quantum dot particles is 1 nm to 100 nm.

[18] A photoelectric conversion element further comprising a first electrode arranged in a pattern and a second electrode arranged opposite to the first electrode, wherein the element described in any of [1] to

[17] is placed between the first electrode and the second electrode.

[19] An imaging device comprising the photoelectric conversion element described in

[18] .

[20] A method for manufacturing an element having at least a quantum dot layer containing quantum dots on which ligands are coordinated to metal ions or atoms present on the surface, and a base layer provided adjacent to the quantum dot layer, wherein the surface of the base layer adjacent to the quantum dot layer is modified with a functional group that can coordinate to metal ions or atoms present on the surface of the quantum dots, and then the quantum dot layer is formed on the surface of the base layer.

[0066] The technology will be described in detail below based on specific examples. However, this technology is not limited in any way to the examples shown below.

[0067] <Compounds for modifying the surface of the underlying layer> As compounds for modifying the surface of the underlying layer, silane coupling agents or phosphonic acid compounds having the functional groups shown in Table 1 were used.

[0068] <Substrate Pretreatment> The Si substrate surface is modified using TEOS (Tetraethyl Orthosilicate) and SiO ２ A substrate with a layer (corresponding to the base layer) is subjected to UV-O at 80°C for 5 min. ３ The process was executed.

[0069] <Surface Modification Treatment of Substrate Layer> A silane coupling agent having the functional groups shown in Table 1 was dissolved in IPA solvent at a concentration of 0.25 wt% to prepare a surface treatment agent. A phosphonic acid compound having the functional groups shown in Table 1 was dissolved in IPA solvent at a concentration of 1.0 wt% to prepare a surface treatment agent.

[0070] After the aforementioned pretreatment, each surface treatment agent was dropped onto the substrate in an arbitrary amount and spin-dried at 3000 rpm. Then, it was heated on a hot plate at 120°C for 5 minutes. Following this, washing was performed by dropping 3 mL of acetonitrile solution three times while rotating at 1000 rpm.

[0071] <Quantum Dot Layer Formation Process> PbS was used as the quantum dot. First, PbS particles were dispersed in an octane solution at a solid content concentration of 50 mg / mL, and the resulting dispersion was filtered through a 0.2 μm PTFE filter to prepare a dispersion of quantum dot particles. In addition, a ligand exchange solution was prepared by dissolving 1,2-ethanedithiol (EDT) in acetonitrile at a concentration of 6.5 μL / 50 mL.

[0072] To each substrate that had undergone the aforementioned surface modification treatment of the underlying layer, a dispersion of quantum dot particles was dropped in an arbitrary amount and spin-dried at 2000 rpm (coating of quantum dots to the underlying layer surface).

[0073] Subsequently, while rotating at 300 rpm, 5 mL of the ligand exchange solution containing the aforementioned EDT was added dropwise to replace the ligands. After that, 5 mL of acetonitrile was added dropwise, and the substrate was spin-dried at 1500 rpm. For each substrate having a quantum dot layer formed on the surface of the resulting underlayer, the presence or absence of film peeling after coating by the above procedure was checked. The results are shown in Table 1. In Table 1, "A" indicates that no film peeling occurred, and "B" indicates that film peeling occurred, where the quantum dot layer peeled off from at least a portion of the surface of the underlayer. Figure 8 is a photograph of the surface of an element where no film peeling occurred ("A"), and Figure 9 is a photograph of the surface of an element where film peeling occurred ("B"). Compared with the surface of the element where no film peeling occurred shown in Figure 8, the surface of the element where film peeling occurred shown in Figure 9 is non-uniform, confirming that the quantum dot layer was deposited non-uniformly.

[0074]

[0075] The results shown in Table 1 confirm that film peeling can be suppressed when the surface of the underlying layer is modified with mercapto groups, substituents having a carbazole skeleton, or carboxylic acid groups that can coordinate to the particle surface of quantum dots.

[0076] Next, elements of Examples 1 to 6 relating to the elements of this technology were formed on a Si substrate patterned with TEOS and ITO (lower electrode) in the same manner as described above. Furthermore, a ZnO layer and an upper ITO transparent electrode were sequentially deposited on the surface of the elements relating to the respective examples to create evaluation elements. Using the obtained evaluation elements, the dark current, external quantum efficiency (EQE), and photoresponse were evaluated under the following conditions. The results are shown in Table 2. Note that the results shown in Table 2 are presented with the measurement result of the evaluation element relating to Example 1 set to 1.00, and the measurement results of each element are converted to relative values ​​with respect to the measurement result of the evaluation element relating to Example 1.

[0077] <Dark Current> In a dark place with external light blocked, at room temperature (25°C), a bias voltage of 1.0V was applied to each element, and the amount of current per unit area was measured.

[0078] <External Quantum Efficiency (EQE)> The EQE was calculated from the relationship between the intensity of the incident light and the measured current when a bias voltage of 1.0 V was applied to each element and light of a single wavelength of 940 nm was irradiated onto it.

[0079] <Photoresponse> A bias voltage of 0.3V was applied to each element, and after irradiating it with light of a single wavelength of 940 nm, the time (fall time) until the photocurrent decayed from 90% to 10% was measured after the light was cut off.

[0080]

[0081] The results shown in Table 2 confirm that surface treatment can also suppress the impact on the sensitivity and response speed of the device. In particular, it can be confirmed that when the chemical structure of the ligands that coordinate to the particle surface of the quantum dots is similar to the chemical structure of the functional groups that modify the surface of the underlying layer adjacent to the quantum dot layer, the properties of the quantum dot layer become stable and the increase in dark current can be suppressed.

[0082] 10 Element 11 Quantum dot layer 12 Quantum dot particles 13-1, 13-2 Ligands 14 Underlayer 15 Functional groups

Claims

1. An element comprising at least a quantum dot layer containing quantum dot particles in which ligands coordinate to metal ions or atoms present on the surface, and a base layer provided adjacent to the quantum dot layer, wherein the surface of the base layer adjacent to the quantum dot layer is modified with a functional group capable of coordinating to metal ions or atoms present on the surface of the quantum dot particles.

2. The device according to claim 1, wherein the functional group is a substituent represented by the following formula (1): A-(L)- .....(1) A is an organometallic substituent or an organic substituent, and L is a single bond or a divalent group.

3. The device according to claim 2, wherein A has one or more structures selected from a carboxylic acid group, a mercapto group, and a carbazole skeleton.

4. The element according to claim 2, wherein A has a mercapto group.

5. The element according to claim 2, wherein A has a carbazole skeleton represented by the following formula (2). R1 and R2 are each H, a halogen, or a monovalent group, and R1 or R2 may bond to an adjacent benzene ring to form a fused ring structure.

6. The element according to claim 5, wherein the carbazole skeleton is one of the skeletons selected from the following.

7. The element according to claim 2, wherein the ligand has the structure of A or a derivative thereof.

8. The element according to claim 1, wherein the underlying layer is composed of an inorganic metal compound.

9. The device according to claim 8, wherein the inorganic metal compound consists of particles ranging from 1 nm to 100 nm in size.

10. The element according to claim 8, wherein the inorganic metal compound is a nitride or an oxide.

11. The device according to claim 8, wherein the inorganic metal compound is composed of an oxide of at least one element selected from Ti, Zn, Mo, In, Sn, Mg, Al, Cu, Fe, Hf, Co, and Ga.

12. The inorganic metal compound is TiO ２ , MoOx, In ２ O ３ , ZnO, SnO ２ , Ga ２ O ３ , Al ２ O ３ , CuO, HfO ２ , Co ２ O ３ , Fe ２ O ３ The device according to claim 10, which is composed of at least one compound selected from the above.

13. The inorganic metal compound is SiO ２ Al ２ O ３ The element according to claim 8, selected from SiN.

14. The device according to claim 8, wherein the functional group is a substituent represented by the following formula (3): A-(L)-B- .....(3) A is an organometallic substituent or an organic substituent, L is a single bond or a divalent group, and B contains Si or P.

15. The device according to claim 1, wherein the quantum dot particles contain two or more elements selected from Pb, S, In, As, Sb, N, Se, Cu, Zn, Sn, Al, P, N, Ga, Cd, Zn, Te, Si, Ge, Sn, and Ag.

16. The device according to claim 15, wherein the quantum dot particles are semiconductors.

17. The device according to claim 1, wherein the average particle size of the quantum dots is 1 nm to 100 nm.

18. A photoelectric conversion element further comprising a first electrode arranged in a pattern and a second electrode positioned opposite the first electrode, wherein the element described in claim 1 is positioned between the first electrode and the second electrode.

19. An imaging device comprising the photoelectric conversion element described in claim 18.

20. A method for manufacturing an element having at least a quantum dot layer containing quantum dots on which ligands are coordinated to metal ions or atoms present on the surface, and a base layer provided adjacent to the quantum dot layer, wherein the surface of the base layer adjacent to the quantum dot layer is modified with a functional group that can coordinate to metal ions or atoms present on the surface of the quantum dots, and then the quantum dot layer is formed on the surface of the base layer.

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