Thin films and methods for making the same, circularly polarized light detecting elements, devices, and methods

Abstract

The film of the present application is a film for circularly polarized light detection, characterized by comprising: a plurality of inorganic layers forming a layered structure and / or a plurality of inorganic chains forming a chain structure, which are formed of a perovskite substance; and a chiral molecule contained in at least a part of a boundary portion between adjacent inorganic layers and / or between adjacent inorganic chains, wherein only one of an S-type chiral molecule or an R-type chiral molecule is present in the chiral molecule, or the presence ratio of either one of the S-type chiral molecule or the R-type chiral molecule is higher than that of the other, and a crystal structure of the perovskite substance is oriented in a prescribed direction.

Description

Technical Field

[0001] This invention relates to thin films and methods for manufacturing the same, circularly polarized light detection elements, devices, and methods. This application claims priority based on Japanese Patent Application No. 2020-093727, filed on May 28, 2020, the contents of which are incorporated herein by reference. Background Technology

[0002] Polarized light image sensors, which visualize the structure and properties of various objects using the phenomenon of polarized light, are known. A polarized light image sensor comprises an array of polarizing mirrors and an array of photodiodes arranged in opposition to groups of polarizing mirrors. The polarizing mirror array comprises groups of four polarizing mirrors with different polarization directions. The signal of linearly polarized light transmitted through the four polarizing mirrors of the same group is converted into an electrical signal as information of one pixel by the photodiodes and output. Based on the signal output from the linearly polarized light, three Stokes parameters can be calculated by combining the sum and difference of the intensities of the orthogonal polarized light components. These parameters can be used to quantify the state of the transmitted light.

[0003] However, visualizing the birefringence, stress distribution, and other states observed when an object is bent using only the three Stokes parameters obtained from linearly polarized light is difficult. These states are known to be visualized using Stokes parameters calculated from the intensity of circularly polarized light, thus a technique for detecting circularly polarized light is desired. Furthermore, when detecting circularly polarized light using the aforementioned polarized light image sensor, a waveplate is required, resulting in a significant reduction in sensitivity. Therefore, a technique for directly detecting circularly polarized light is desired.

[0004] Non-patent literature 1 discloses (PbI6). 4- (Octahedral structure) One-dimensional arrangement (i.e., by making (PbI6) 4- The structure, which is arranged in a common plane and surrounded by chiral molecules (1-phenylethylamine), serves as a structure for directly detecting circularly polarized light in the wavelength region around 400 nm.

[0005] Existing technical documents

[0006] Non-patent literature

[0007] Non-patent literature 1: Chao Chen et al., Nature Communications, volume 10, article number: 1927 (2019) Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] Currently, there is a demand for novel thin films and their fabrication methods that promote large chiral structures in the overall system for the direct detection of circularly polarized light.

[0010] The present invention was made in view of the above circumstances, and its object is to provide a thin film capable of directly detecting circularly polarized light over a wide wavelength region, a method for manufacturing the same, a circularly polarized light detection element, device, and method having the thin film.

[0011] Methods for solving problems

[0012] To address the aforementioned issues, the present invention employs the following methods.

[0013] (1) One aspect of the present invention is a thin film for circularly polarized light detection, comprising: a plurality of inorganic layers forming a layered structure and / or a plurality of inorganic chains forming a chain structure, formed of a perovskite material; and chiral molecules contained in at least a portion of the boundaries between adjacent inorganic layers and / or between the inorganic chains, wherein the chiral molecules contain only one of S-type chiral molecules or R-type chiral molecules, or the proportion of one of S-type chiral molecules or R-type chiral molecules is higher than the proportion of the other, and the crystal structure of the perovskite material is oriented in a predetermined direction.

[0014] (2) In the thin film described in (1) above, the absorption intensity per unit thickness is preferably 50,000 cm⁻¹. -1 Above 500,000cm -1 the following.

[0015] (3) In any one of (1) or (2) above, the surface roughness Ra is preferably 1 nm or more and 30 nm or less.

[0016] (4) In any one of (1) to (3) above, the film is preferably formed by the aforementioned chiral molecules forming an organic layer at the aforementioned boundary, the aforementioned inorganic layer and the aforementioned organic layer being stacked on each other, and / or the aforementioned chiral molecules surrounding the aforementioned inorganic chain.

[0017] (5) In any one of (1) to (4) above, the chiral molecules are preferably fixed to the inorganic layer and / or the inorganic chain.

[0018] (6) In any one of (1) to (5) above, the chiral molecule is preferably bonded to the inorganic layer and / or the inorganic chain by a functional group covalently bonded to the chiral carbon atom constituting the chiral molecule.

[0019] (7) In the thin film described in (6) above, preferably: the aforementioned functional group is a substituent that can have a charge, and the substituent forms a bond with the aforementioned perovskite-type material through a halide ion, thereby fixing the aforementioned chiral molecule to the aforementioned inorganic layer and / or the aforementioned inorganic chain.

[0020] (8) The thin film of any one of (1) to (7) above is preferably composed of the perovskite-type material and the chiral molecule forming a compound A2BX4 and / or ABX3 composed of three ions A, B and X, wherein the aforementioned ions B and X form a plurality of unit units having an octahedral structure, and the aforementioned octahedral structures containing adjacent aforementioned unit units share a vertex and / or face with each other.

[0021] (9) The thin film described in (8) above has multiple inorganic layers constituting a layered structure, and the perovskite-type material and the chiral molecule constitute a compound A2BX4 composed of three ions A, B and X. The ions B and X form multiple unit units with an octahedral structure, and the octahedral structures containing adjacent unit units share a vertex with each other.

[0022] (10) The thin film described in (8) above has multiple inorganic chains constituting a chain-like structure, and the perovskite-type material and the chiral molecule constitute a compound ABX3 composed of three ions A, B and X. The ions B and X form multiple unit units with an octahedral structure, and the octahedral structures containing adjacent unit units share a common face.

[0023] (11) In any one of (8) to (10) above, preferably: the aforementioned ion A is an aromatic compound containing ethylammonium ions, the aforementioned ion B is lead ions or tin ions, and the aforementioned ion X is a halide ion.

[0024] (12) One aspect of the present invention is a method for manufacturing a thin film according to any one of (1) to (11) above, comprising: a first step of dissolving the precursor of the perovskite-type material, the chiral molecule, and an organohalide that can sublimate by heating and react with a portion of the constituent elements of the perovskite-type material in a solvent; a second step of coating the solution obtained in the first step onto a substrate by spin coating to form a pre-treatment coating film on the substrate; and a third step of heating the pre-treatment coating film to sublimate the organohalide contained in the pre-treatment coating film.

[0025] (13) In the method for manufacturing the thin film described in (12) above, preferably, the precursor of the perovskite-type material is lead halide, and the organic halide is halomethylammonium or formamidinium halide.

[0026] (14) In the method for manufacturing the thin film described in (13) above, it is preferred that the halogen atom contained in the aforementioned lead halide and the aforementioned organic halide is any one of bromine atom, chlorine atom or iodine atom.

[0027] (15) One aspect of the circularly polarized light detection element of the present invention comprises the thin film described in any one of (1) to (11) above.

[0028] (16) In the circularly polarized light detection element described in (15) above, it is preferred that it is formed by stacking a negative electrode layer, the aforementioned thin film, and a positive electrode layer in sequence, and at least one of the aforementioned negative electrode layer and the aforementioned positive electrode layer has light transmittance.

[0029] (17) One aspect of the device of the present invention is formed by incorporating the circularly polarized light detection element described in any one of (15) or (16) above.

[0030] (18) One aspect of the present invention is a method for inducing an R or S configuration chiral structure in a perovskite material comprising a plurality of inorganic layers constituting a layered structure and / or a plurality of inorganic chains constituting a chain structure. The method includes a step of including chiral molecules containing either an S-type chiral molecule or an R-type chiral molecule, or chiral molecules containing either an S-type chiral molecule or an R-type chiral molecule in a higher proportion than the other, in a manner oriented in a predetermined direction according to the crystal structure of the perovskite material, in at least a portion of the boundaries between adjacent inorganic layers and / or inorganic chains contained in the perovskite material.

[0031] (19) One aspect of the present invention is a chiral thin film formed from a perovskite-type material, the thin film comprising: a plurality of inorganic layers constituting a layered structure and / or a plurality of inorganic chains constituting a chain-like structure; and chiral molecules contained in at least a portion of the boundaries between adjacent inorganic layers and / or between the inorganic chains, wherein the chiral molecules are chiral molecules that contain only one of S-type chiral molecules or R-type chiral molecules, or chiral molecules that are present in a higher proportion than the other, and the crystal structure of the perovskite-type material is oriented in a predetermined direction.

[0032] Invention Effects

[0033] According to the present invention, a thin film capable of directly detecting circularly polarized light over a wide wavelength range, a method for manufacturing the same, a circularly polarized light detection element, a device, and a method comprising the thin film are provided. Attached Figure Description

[0034] [ Figure 1 [This is a cross-sectional view of a thin film according to one embodiment of the present invention.]

[0035] [ Figure 2 [This is a cross-sectional view of a thin film according to another embodiment of the present invention.]

[0036] [ Figure 3 [This is a cross-sectional view of a circularly polarized light detection element according to one embodiment of the present invention.]

[0037] [ Figure 4 [This is a cross-sectional view of a circularly polarized light detection element according to another embodiment of the present invention.]

[0038] [ Figure 5 [Graphs showing the results of XRD analysis of the films of Example 1, Example 2 and Comparative Example 3.]

[0039] [ Figure 6 [Graphs showing the results of XRD analysis of the films of Example 4, Example 5 and Comparative Example 6.]

[0040] [ Figure 7 [Graphs showing the results of XRD analysis of the films of Examples 1 and 4 using a two-dimensional detector.]

[0041] [ Figure 8 [Graphs showing the light absorption spectra and circular polarization dichroism spectra of the thin films of Example 1, Example 2, and Comparative Example 3.]

[0042] [ Figure 9 [Graphs showing the light absorption spectra and circular polarization dichroism spectra of the thin films of Examples 4, 5, and Comparative Example 6.]

[0043] [ Figure 10 The graphs show the light absorption spectrum and circular polarization dichroism spectrum of the thin films of Comparative Examples 8 and 9.

[0044] [ Figure 11 [Graphical representation of the results of measuring the photocurrent and dark current characteristics of the thin film of Example 1.]

[0045] [ Figure 12 [Graphical representation showing the results of measuring the on-off characteristics of the thin film of Example 1.]

[0046] [ Figure 13 [Graphical representation of the results of measuring the photocurrent and dark current characteristics of the thin film of Example 4.]

[0047] [ Figure 14 [A graph showing the results of the measurement of the switching characteristics of the thin film of Example 4.] Detailed Implementation

[0048] (Layered structure)

[0049] The following description, using accompanying drawings, details a thin film and its manufacturing method, a circularly polarized light detection element, a device, and a method to which embodiments of the present invention are applied. It should be noted that, for ease of understanding and convenience, the accompanying drawings used in the following description sometimes show enlarged features, and the dimensional ratios of the constituent elements are not necessarily consistent with reality. Furthermore, the materials, dimensions, etc., illustrated in the following description are merely examples, and the present invention is not limited thereto; appropriate modifications can be made without altering its spirit and scope.

[0050] Figure 1 A cross-sectional view illustrating the structure of a thin film 100 according to one embodiment of the present invention is shown. The thin film 100 is a chiral thin film formed from a perovskite-type material for circularly polarized light detection. The thin film 100 mainly comprises multiple inorganic layers 102 forming a layered structure from a perovskite-type material 101, and chiral molecules 103. It should be noted that... Figure 1 In this paper, amino groups are used as an example of functional groups of chiral molecule 103, but the present invention is not limited to amino groups.

[0051] Each inorganic layer 102 is a sheet approximately 1 nm thick, composed of multiple perovskite-type materials forming a polycrystalline structure, which constitute part of a compound A2BX4 composed of three ions A, B, and X. The crystal structure of the perovskite-type materials exhibits texture and is oriented along a predetermined direction. Specifically, ions B and X form multiple unit cells (BX6) with an octahedral structure. 4- Furthermore, adjacent octahedral structures share a vertex. Ion B is positioned at the center of the octahedron, and ion X is positioned at the vertices of the octahedron. Additionally, ion A is positioned circumscribed to the octahedral structure of each unit. It should be noted that ion A is a chiral molecule 103. That is, the perovskite-type substance and the chiral molecule 103 constitute a compound A2BX4 composed of three ions: A, B, and X.

[0052] The inorganic layer 102 is arranged with octahedral structures sharing vertices, and chiral molecules 103 are incorporated between its layers. Thus, since it becomes a different structure from the structure arranged with octahedral structures sharing faces (which has the ability to directly detect circularly polarized light in the wavelength region around 400 nm), the absorption positions change. As a result, it can impart the ability to directly detect circularly polarized light with a wavelength region extended to 500 nm and above. Furthermore, by having the octahedral structures share vertices, the absorption capacity of circularly polarized light can be increased.

[0053] Examples of ion A include aromatic compounds containing ethylammonium ions. Examples of ion B include lead ions and tin ions. Examples of ion X include halide ions. Examples of halide ions include chloride ions, bromide ions, and iodide ions. Iodide ions are preferred as halide ions.

[0054] Chiral molecule 103 is contained in at least a portion of the boundary 104 between adjacent inorganic layers 102, and is fixed by bonding with a perovskite-type material on the surface of the inorganic layer 102. More specifically, chiral molecule 103 is bonded to the perovskite-type material by a functional group covalently bonded to the chiral carbon atom constituting chiral molecule 103. This functional group is a substituent capable of carrying a charge, and the substituent and the perovskite-type material can form a bond by a halide ion. Preferably, an amino group is used as the functional group. This is achieved by using an amino group (NH3) + (e.g., PbI6) 4- I - Bonding, in (PbI6) 4- Chirality is generated in the formed inorganic layer, which then exhibits the ability to absorb circularly polarized light. Preferably, the chiral molecule 103 has one or more aromatic rings, more preferably two or more. Furthermore, aromatic rings with a shared side of a benzene ring, such as naphthalene or anthracene rings, are preferred as they increase the intensity of circularly polarized light absorption.

[0055] It should be noted that chiral molecule 103 exists in both R-type and S-type forms. R-type or S-type chiral molecule 103 strongly absorbs circularly polarized light, either dextrorotatory or levorotatory. Here, four different bonding groups are bonded to a chiral carbon, with the lowest atomic number placed furthest away. The remaining three bonding groups are arranged clockwise from largest to smallest atomic number, and are called R-type, while those arranged counterclockwise are called S-type. For example, R-(+)-1-(1-naphthyl)ethylamine hydrobromide, as shown in formula (1), can be considered as R-type. For example, S-(-)-1-(1-naphthyl)ethylamine hydrobromide, as shown in formula (2), can be considered as S-type.

[0056] [Chemical Formula 1]

[0057]

[0058] [Chemical Formula 2]

[0059]

[0060] When the chiral molecule 103 reacts with 1.2 or more Pb ions relative to the inorganic layer 102, it typically forms a layered structure (A2BX4). Conversely, when the chiral molecule 103 reacts with 0.75 or less Pb ions relative to the inorganic layer 102, it typically forms a chain structure (ABX3). When the chiral molecule 103 reacts with more than 0.75 but less than 1.2 Pb ions relative to the inorganic layer 102, a structure consisting of a mixture of chain and layered structures is typically formed. In the case of a structure consisting of a mixture of chain and layered structures, the perovskite-type material and the chiral molecule constitute compounds A2BX4 and ABX3, which are composed of three ions A, B, and X. Examples of ion A include aromatic compounds containing ethylammonium ions. Examples of ion B include lead ions and tin ions. Examples of ion X include halide ions. Examples of halide ions include chloride ions, bromide ions, and iodide ions. Iodide ions are preferred as halide ions. The absorption capacity of circularly polarized light can be adjusted by regulating the ratio of chiral molecule 103 to Pb in inorganic layer 102.

[0061] Figure 1 The illustration shows a case where chiral molecules 103 form an organic layer 105 at the boundary portion 104, and inorganic layers 102 are stacked on top of each other. The number of stacked inorganic layers 102 is not particularly limited, but when the thin film 100 is used in circularly polarized light detection elements, etc., from the viewpoint of facilitating current flow along the thickness direction D, the thickness of the thin film 100 is preferably in the range of 100 to 500 nm. Furthermore, from the viewpoint of protecting the chiral molecules 103, it is preferable to stack them such that the uppermost and lowermost layers are inorganic layers 102.

[0062] From the viewpoint of efficiently transmitting irradiated light so that the perovskite-type material absorbs the irradiated light, the surface roughness Ra (arithmetic mean roughness) of each thin film 100 is preferably 1 nm or more and 30 nm or less. As long as the arithmetic mean roughness Ra of the thin film 100 is 30 nm or less, leakage of the circularly polarized light detection element 110 can be suppressed. The arithmetic mean roughness Ra can be measured, for example, using an atomic force microscope (AFM). When measuring with an atomic force microscope, the arithmetic mean roughness Ra can be obtained, for example, from an observation image obtained by measuring using an atomic force microscope manufactured by Shimadzu Corporation, with the scanning range and scanning mode set to appropriate values ​​(specifically, for example, scanning mode: dynamic mode).

[0063] Furthermore, since the perovskite material needs to absorb irradiated light efficiently, the absorption intensity per unit thickness of the thin film 100 is expected to be 50,000 cm⁻¹. -1 Above 500,000cm -1The following should be noted: the absorption intensity per unit thickness is set as the value of the absorption intensity per unit thickness at the peak wavelength of the highest absorption intensity peak. The absorption intensity of the thin film 100 is measured using the transmission method.

[0064] Figure 3 This is a cross-sectional view of a circularly polarized light detection element 110 including a thin film 100. The circularly polarized light detection element 110 is mainly formed by sequentially stacking a negative electrode layer 106, a thin film 100, and a positive electrode layer 107. In order for the perovskite material in the thin film 100 to absorb light (circularly polarized light), at least one of the negative electrode layer 106 and the positive electrode layer 107 is transparent. The negative electrode layer 106 is bonded to one side of the thin film 100 in the thickness direction by a negative electrode side bonding layer 108 (electron transport layer) formed of, for example, SnO2, TiO2, etc. The positive electrode layer 107 is bonded to the other side of the thin film 100 in the thickness direction by a positive electrode side bonding layer 109 (hole transport layer) formed of, for example, BCP (Bathocuproine (registered trademark)), spiro-MeOTAD, TPD, etc. When the negative electrode layer 106 is transparent, the negative electrode side bonding layer 108 is also transparent. Furthermore, when the positive electrode layer 107 is transparent, the positive electrode side adhesive layer 109 is also transparent.

[0065] In the circularly polarized light detection element 110, the inorganic layer 102 constituting the thin film 100 has a polycrystalline structure, therefore the thin film 100 has high light absorption (absorption intensity at wavelength 488 nm: approximately 50,000 cm⁻¹). -1 The light irradiating the thin film 100 is circularly polarized, or contains circularly polarized light, and the current caused by the absorbed circularly polarized light can be detected. It should be noted that by using only R-type or S-type chiral molecules, R- or S-type chiral structures can be induced in the perovskite structure, enabling selective absorption of right-handed or left-handed circularly polarized light and detection of the current. Furthermore, if the proportion of either R-type or S-type is higher than that of the other, R- or S-type chiral structures can also be induced in the perovskite structure, enabling selective absorption of right-handed or left-handed circularly polarized light and detection of the current.

[0066] (Manufacturing method of layered structures)

[0067] The shape of the perovskite-type material can be controlled by adjusting the ratio of the precursor, chiral molecule, and organohalide. For example, in the case of forming a layered structure, the thin film 100 can be manufactured mainly according to the following steps. First, a perovskite-type material precursor, which is the raw material of the thin film 100, is dissolved in a solvent at a ratio of 0.5 mol / L to 2 mol / L, a chiral molecule at a ratio of 0.5 mol / L to 2 mol / L, and an organohalide that can sublimate by heat and react with a portion of the constituent elements of the perovskite-type material at a ratio of less than 1 mol / L (preferably 0.4 mol / L to 0.8 mol / L) (first step). As a solvent, dimethylformamide (DMF), dimethyl sulfoxide (DMSO), γ-butyrolactone, etc., can be used, for example. It should be noted that in order to substantially form a layered structure, the ratio is calculated and coordinated such that the chiral molecule is 1.2 or more molecules relative to the Pb ion molecule of the inorganic layer 102.

[0068] Examples of precursors for perovskite-type substances include lead halides. Examples of organohalides include halomethylammonium or formamidinium halide. Examples of halogen atoms contained in lead halides and organohalides include, for example, any one of bromine, chlorine, or iodine atoms.

[0069] Next, the solution (mixture) obtained in the first step is dropped onto a separately prepared substrate using a spin coating method, and the substrate is rotated at 1000 rpm to 5000 rpm to form a pre-treatment coating film on the substrate (second step). The material of the substrate is not limited.

[0070] Next, the pre-treatment coating is heated using a heating device to sublimate the organic halides contained in the pre-treatment coating (third step), thereby obtaining a thin film composed of a polycrystalline inorganic layer and chiral molecules distributed therebetween. Here, the heating temperature is preferably set to 70°C to 120°C and the heating time is set to 15 minutes to 60 minutes.

[0071] By performing the second and third processes without crystallizing the solution obtained in the first process, the inorganic layer 102 of the thin film 100 obtained after the third process has texture and becomes a polycrystalline material that is preferentially oriented in a specific direction rather than randomly.

[0072] For the thin film 100 obtained after the third process, a positive electrode layer 107 is formed on one side of the thickness direction and a negative electrode layer 106 is formed on the other side using known film deposition methods such as vacuum evaporation and sputtering, thereby obtaining a circularly polarized light detection element 110 that can output circularly polarized light information as an electrical signal. It should be noted that known film deposition methods such as vacuum evaporation, spin coating, and sputtering can be used to form a positive electrode side bonding layer 109 and a negative electrode side bonding layer 108 between the thin film 100 and the positive electrode layer 107, and between the thin film 100 and the negative electrode layer 106, respectively.

[0073] As described above, the thin film 100 of this embodiment is a layered structure with multiple inorganic layers 102 stacked together. Chiral molecules 103 with absorbance for circularly polarized light are immobilized in the two-dimensionally extended nanospace sandwiched between adjacent inorganic layers 102. The chiral molecules 103 induce chirality in the arrangement of the inorganic layers 102, thus extending the absorption wavelength region of circularly polarized light based on the inorganic layers 102 to a wide range of 350 to 800 nm.

[0074] Furthermore, the inorganic layer 102 has a polycrystalline structure and high conductivity. Therefore, by connecting electrodes at both ends in the thickness direction, it is possible to detect the current caused by circularly polarized light absorbed by the inorganic layer 102, whether the light irradiating the thin film 100 is circularly polarized or contains circularly polarized light. That is, the inorganic layer 102, formed using only R-configuration chiral molecules or S-configuration chiral molecules, can selectively absorb right-handed or left-handed circularly polarized light and detect its current.

[0075] Furthermore, the thin film 100 of this embodiment eliminates the need for polarizing mirrors and waveplates when detecting circularly polarized light, thus achieving a high extinction ratio. It enables direct detection of circularly polarized light, which cannot be directly detected by conventional photodetectors, with high sensitivity and high resolution.

[0076] Therefore, the thin film 100 of this embodiment can be used as a circularly polarized light detection element, enabling the development of various devices such as polarization cameras incorporating a circularly polarized light detection element (which incorporates the thin film 100 of this embodiment). By directly detecting circularly polarized light, information such as the intensity distribution of birefringence, which cannot be obtained from linearly polarized light, can be obtained.

[0077] (Chain-like structure)

[0078] Next, the case of chain-like structures will be explained. Figure 2A cross-sectional view illustrating the structure of a thin film 200 according to one embodiment of the present invention is shown. The thin film 200 is a chiral thin film formed from a perovskite-type material. The thin film 200 mainly comprises multiple inorganic chains 202 forming a chain-like structure from a perovskite-type material 201, and chiral molecules 203. The chain-like structure is preferred because it increases the anisotropy factor compared to a layered structure. It should be noted that... Figure 2 In this paper, amino groups are used as an example of functional groups of chiral molecule 203, but the present invention is not limited to amino groups.

[0079] Each inorganic chain 202 is a chain-like structure with a diameter of approximately 1 nm, composed of multiple perovskite-type substances forming a polycrystalline structure, which constitute part of the compound ABX3 composed of three ions A, B, and X. The crystal structure of the perovskite-type substances exhibits texture and is oriented along a prescribed direction. Specifically, ions B and X form multiple unit cells (BX6) with an octahedral structure. 4- Furthermore, adjacent unit cells share a common face. Ion B is positioned at the center of the octahedron, and ion X is positioned at the vertices of the octahedron. Additionally, ion A is positioned circumscribed to the octahedron structure of each unit cell. It should be noted that ion A is a chiral molecule 203. That is, the aforementioned perovskite-type substance and the aforementioned chiral molecule constitute a compound ABX3 composed of three ions, A, B, and X.

[0080] The inorganic chain 202 is arranged such that octahedral structures share faces, and chiral molecules 203 surround the inorganic chain 202. Thus, since it becomes a different structure from the structure arranged by sharing vertices (which has the ability to directly detect circularly polarized light in the wavelength region around 500 nm), the absorption position changes. As a result, the ability to directly detect circularly polarized light in the wavelength region around 400 nm can be acquired. Furthermore, by sharing faces among the octahedral structures, the absorption capacity for circularly polarized light can be increased.

[0081] Examples of ion A include aromatic compounds containing ethylammonium ions. Examples of ion B include lead ions and tin ions. Examples of ion X include halide ions. Examples of halide ions include F. - Cl - ,Br - and I - etc. As a halide ion, I is preferred. - .

[0082] Chiral molecule 203 is contained in at least a portion of the boundary 204 between adjacent inorganic chains 202 and is fixed by bonding with a perovskite-type material on the surface of the inorganic chain 202. More specifically, chiral molecule 203 is bonded to the perovskite-type material by a functional group covalently bonded to the chiral carbon atom constituting chiral molecule 203. This functional group is a substituent capable of carrying a charge, and the substituent and the perovskite-type material can form a bond by a halide ion. Preferably, an amino group is used as the functional group. This is achieved by using an amino group (NH3) + (e.g., PbI6) 4- I - Bonding, in (PbI6) 4- The formed inorganic chain exhibits chirality, thus displaying the ability to absorb circularly polarized light. Preferably, the chiral molecule 203 has one or more aromatic rings. Furthermore, aromatic rings with a shared side of a benzene ring, such as naphthalene or anthracene rings, are preferred as they increase the intensity of circularly polarized light absorption.

[0083] It should be noted that chiral molecule 203 exists in both R-type and S-type forms. R-type or S-type chiral molecule 203 strongly absorbs circularly polarized light, whether dextrorotatory or levorotatory. For example, R-(+)-1-(1-naphthyl)ethylamine hydrobromide as shown in formula (1) above can be considered as an R-type. For example, S-(-)-1-(1-naphthyl)ethylamine hydrobromide as shown in formula (2) above can be considered as an S-type.

[0084] Figure 2 The illustration shows a chiral molecule 203 forming an organic layer 205 at the boundary 204, with the organic layer 205 covering the surrounding area of ​​the inorganic chain 202. The inorganic chain 202 is sometimes linked to other inorganic chains 202 in the b-axis direction via the organic layer 205. Furthermore, in the c-axis direction, the aromatic rings of the organic molecules bonded to the inorganic chains are stacked together. The number of linked inorganic chains 202 is not limited. When the thin film 200 is used in circularly polarized light detection elements, etc., from the viewpoint of facilitating current flow along the thickness direction D, the thickness of the thin film 200 is preferably in the range of 100 to 500 nm.

[0085] From the viewpoint of efficiently transmitting irradiated light so that the perovskite-type material absorbs the irradiated light, the surface roughness Ra (arithmetic mean roughness) of each thin film 200 is preferably 1 nm or more and 30 nm or less. Furthermore, when the arithmetic mean roughness Ra of the thin film 200 is 30 nm or less, leakage of the circularly polarized light detection element 220 can be suppressed. The arithmetic mean roughness Ra can be measured, for example, using an atomic force microscope (AFM). When measuring using an atomic force microscope, the arithmetic mean roughness Ra can be obtained, for example, from an observation image obtained by measuring using an atomic force microscope manufactured by Shimadzu Corporation, with the scanning range and scanning mode set to appropriate values ​​(specifically, for example, scanning mode: dynamic mode).

[0086] Furthermore, since the perovskite material needs to absorb irradiated light efficiently, the absorption intensity per unit thickness of the thin film 200 is expected to be 50,000 cm⁻¹. -1 Above 500,000cm -1 The following should be noted: the absorption intensity per unit thickness is set to the peak wavelength of the highest absorption intensity peak. The absorption intensity of thin film 200 was measured using the transmission method.

[0087] Figure 4 This is a cross-sectional view of a circularly polarized light detection element 220 including a thin film 200. The circularly polarized light detection element 220 is mainly formed by sequentially stacking a negative electrode layer 206, a thin film 200, and a positive electrode layer 207. To allow the perovskite material within the thin film 200 to absorb light (circularly polarized light), at least one of the negative electrode layer 206 and the positive electrode layer 207 is transparent. The negative electrode layer 206 is bonded to one side of the thin film 200 in the thickness direction via a negative electrode-side adhesive layer 208 (electron transport layer) formed of, for example, SnO2 or TiO2. The positive electrode layer 207 is bonded to the other side of the thin film 200 in the thickness direction via a positive electrode-side adhesive layer 209 (hole transport layer) formed of, for example, BCP (Bathocuproine, a registered trademark), spiro-MeOTAD, or TPD. Since the negative electrode layer 206 is transparent, the negative electrode-side adhesive layer 208 is also designed to be transparent. Furthermore, if the positive electrode layer 207 is transparent, the positive electrode side adhesive layer 209 is also designed to be transparent.

[0088] In the circularly polarized light detection element 220, the inorganic chain 202 constituting the thin film 200 has a polycrystalline structure, therefore the thin film 200 has high light absorption (absorption intensity at wavelength 375nm: approximately 50,000 cm⁻¹). -1The light irradiated onto the thin film 200 is circularly polarized, or contains circularly polarized light, and the current induced by the absorbed circularly polarized light can be detected. It should be noted that by using only R-type or S-type chiral molecules, R- or S-type chiral structures can be induced in the perovskite structure, enabling the selective absorption of right-handed or left-handed circularly polarized light and the detection of its current.

[0089] (Manufacturing method of chain-like structures)

[0090] The shape of the perovskite-type material can be controlled by adjusting the ratio of the precursor, chiral molecule, and organohalide. For example, when a chain structure is formed, the thin film 200 can be manufactured mainly by the following steps. First, a perovskite-type material precursor, which is the raw material for the thin film 200, is dissolved in a solvent at a ratio of 0.5 mol / L to 2 mol / L, a chiral molecule at a ratio of 0.5 mol / L to 2 mol / L, and an organohalide that can sublimate upon heating and react with a portion of the constituent elements of the perovskite-type material at a ratio of 1 mol / L or less (preferably 0.4 mol / L to 0.8 mol / L) (first step). As a solvent, dimethylformamide (DMF), dimethyl sulfoxide (DMSO), γ-butyrolactone, etc., can be used, for example. It should be noted that when multiple inorganic chains are to substantially form a chain structure, the ratio is calculated and coordinated such that the chiral molecule is 0.75 molecules or less relative to 1 molecule of Pb ion in the inorganic chain 202.

[0091] Examples of precursors for perovskite-type substances include lead halides. Examples of organohalides include halomethylammonium or formamidinium halide. Examples of halogen atoms contained in lead halides and organohalides include, for example, any one of bromine, chlorine, or iodine atoms.

[0092] Next, the solution (mixture) obtained in the first step is dropped onto a separately prepared substrate using a spin coating method, and the substrate is rotated at 1000 rpm to 5000 rpm to form a pre-treatment coating film on the substrate (second step). The material of the substrate is not limited.

[0093] Next, the pre-treatment coating is heated using a heating device to sublimate the organic halides contained in the pre-treatment coating (third step), thereby obtaining a thin film composed of a polycrystalline inorganic layer and chiral molecules distributed therebetween. Here, the heating temperature is preferably set to 70°C to 120°C and the heating time is set to 15 minutes to 60 minutes.

[0094] By performing the second and third processes without crystallizing the solution obtained in the first process, the inorganic chains 202 of the thin film 200 obtained after the third process have texture and become a polycrystalline material that is not random but preferentially oriented in a specific direction.

[0095] For the thin film 200 obtained after the third process, a positive electrode layer 207 is formed on one side in the thickness direction and a negative electrode layer 206 is formed on the other side using known film deposition methods such as vacuum evaporation and sputtering, thereby obtaining a circularly polarized light detection element 220 that can output circularly polarized light information as an electrical signal. It should be noted that known film deposition methods such as vacuum evaporation, spin coating, and sputtering can be used to form a positive electrode side bonding layer 209 and a negative electrode side bonding layer 208 between the thin film 200 and the positive electrode layer 207, and between the thin film 200 and the negative electrode layer 206, respectively.

[0096] As described above, the thin film 200 of this embodiment is a chain-like structure with inorganic chains 202 arranged thereon. Chiral molecules 203 with absorbance for circularly polarized light are immobilized in a one-dimensional nanospace sandwiched between adjacent inorganic chains 202. The chiral molecules 203 induce chirality in the arrangement of the inorganic chains 202, thus extending the absorption wavelength region of circularly polarized light based on the inorganic chains 202 to a wide range of 350 nm to 800 nm.

[0097] Furthermore, the inorganic chain 202 has a polycrystalline structure and high conductivity. Therefore, by connecting electrodes at both ends in the thickness direction, it is possible to detect the current caused by circularly polarized light absorbed by the inorganic chain 202, whether the light irradiating the thin film 200 is circularly polarized or contains circularly polarized light. That is, the inorganic chain 202, formed using only R-configured chiral molecules or S-configured chiral molecules, can selectively absorb right-handed or left-handed circularly polarized light and detect its current. In addition, when the proportion of either R-type or S-type is higher than that of the other, an R- or S-configured chiral structure can be induced in the perovskite structure, enabling the selective absorption of right-handed or left-handed circularly polarized light and detection of its current.

[0098] Furthermore, the thin film 200 of this embodiment eliminates the need for polarizers and waveplates when detecting circularly polarized light, thus achieving a high extinction ratio. It enables direct detection of circularly polarized light, which cannot be directly detected by conventional photodetectors, with high sensitivity and high resolution.

[0099] Therefore, the thin film 200 of this embodiment can be used as a circularly polarized light detection element, enabling the development of various devices such as polarization cameras incorporating a circularly polarized light detection element (which incorporates the thin film 200 of this embodiment). By directly detecting circularly polarized light, information such as the intensity distribution of birefringence, which cannot be obtained from linearly polarized light, can be obtained.

[0100] As explained above, by incorporating chiral molecules 103, 203, which contain only one of the S-type chiral molecules 103, 203 or R-type chiral molecules 103, 203, or chiral molecules 103, 203 of the same type but in a higher proportion than the other, into at least a portion of the boundaries between adjacent inorganic layers 102 and / or inorganic chains 202 contained in a perovskite-type material in a manner that aligns them in a predetermined direction according to the crystal structure of the perovskite-type material, it is possible to induce an R or S-type chiral structure in the perovskite structure of the perovskite-type material containing multiple inorganic layers 102 constituting a layered structure and / or multiple inorganic chains 202 constituting a chain-like structure, thereby enabling direct detection of circularly polarized light.

[0101] Example

[0102] The effects of the present invention are further illustrated below with reference to specific embodiments. It should be noted that the present invention is not limited to the following embodiments and can be implemented with appropriate modifications without altering its spirit.

[0103] (Example 1)

[0104] The thin film manufacturing method of the above embodiment is carried out according to the following steps to prepare a thin film. 1 g of R-(+)-1-(1-naphthyl)ethylamine (R-1-NEA) and 500 μL of hydrogen iodide (HI) are mixed, and the resulting mixture is stirred at 0°C for 2 hours to obtain 2.8 g of R-(+)-1-(1-naphthyl)ethylamine hydrobromide ((R-1-NEA)I). Next, 500 μL of dimethylformamide (DMF) is used as a solvent, and 230 mg of lead iodide (PbI2), 299 mg of ((R-1-NEA)I), and 60 mg of methylamine hydroiodide (MAI) are mixed therein. The resulting mixture is stirred at 70°C for 1 hour to prepare a solution containing the thin film raw materials. The prepared solution is coated onto a separately prepared substrate, and a pre-treatment coating is formed by spin coating (1000 rpm, 10 s / 5000 rpm, 60 s). The pre-treatment coating was heated at 100°C for 30 minutes to obtain a thin film of (R-1-NEA)2PbI4.

[0105] (Example 2)

[0106] 1 g of S-(-)-1-(1-naphthyl)ethylamine (S-1-NEA) and 500 μL of hydrogen iodide (HI) were mixed, and the resulting mixture was stirred at 0°C for 2 hours to obtain 2.9 g of S-(+)-1-(1-naphthyl)ethylamine hydrobromide ((S-1-NEA)I). Next, 500 μL of dimethylformamide (DMF) was used as a solvent to mix 230 mg of lead iodide (PbI2), 299 mg of ((S-1-NEA)I), and 60 mg of methylamine hydroiodide (MAI). The resulting mixture was stirred at 70°C for 1 hour to prepare a solution containing the film raw materials. Then, spin coating was performed using the same procedure as in Example 1, followed by heating (100°C, 30 minutes) to obtain a film of (S-1-NEA)2PbI4.

[0107] (Comparative Example 3)

[0108] 1 g of racemic DL-1-(1-naphthyl)ethylamine (rac-1-NEA) and 500 μL of hydrogen iodide (HI) were mixed and stirred at 0°C for 2 hours to obtain 2.8 g of DL-1-(1-naphthyl)ethylamine hydrobromide ((rac-1-NEA)I). Next, 230 mg of lead iodide (PbI2), 299 mg of ((rac-1-NEA)I), and 60 mg of methylamine hydroiodide (MAI) were mixed into 500 μL of dimethylformamide (DMF) as a solvent. The resulting mixture was stirred at 70°C for 1 hour to prepare a solution containing the film raw material. Then, spin coating was performed using the same procedure as in Example 1, followed by heating (100°C, 30 minutes) to obtain a film of (rac-NEA)2PbI4.

[0109] (Example 4)

[0110] The thin film manufacturing method of the above embodiment is carried out according to the following steps to prepare a thin film. 1 g of R-(+)-1-(1-naphthyl)ethylamine (R-1-NEA) and 500 μL of hydrogen iodide (HI) are mixed, and the resulting mixture is stirred at 0°C for 2 hours to obtain 2.8 g of R-(+)-1-(1-naphthyl)ethylamine hydrobromide ((R-1-NEA)I). Next, 500 μL of dimethylformamide (DMF) is used as a solvent, and 230 mg of lead iodide (PbI2), 112 mg of ((R-1-NEA)I), and 60 mg of methylamine hydrogen iodide (MAI) are mixed therein. The resulting mixture is stirred at 70°C for 1 hour to prepare a solution containing the thin film raw materials. The prepared solution is coated onto a separately prepared substrate, and a pre-treatment coating is formed by spin coating. The pre-treatment coating was heated at 100°C for 30 minutes to obtain a thin film of (R-1-NEA)PbI3.

[0111] (Example 5)

[0112] 1 g of S-(-)-1-(1-naphthyl)ethylamine (S-1-NEA) and 500 μL of hydrogen iodide (HI) were mixed, and the resulting mixture was stirred at 0°C for 2 hours to obtain 2.9 g of S-(+)-1-(1-naphthyl)ethylamine hydrobromide ((S-1-NEA)I). Next, 500 μL of dimethylformamide (DMF) was used as a solvent to mix 230 mg of lead iodide (PbI2), 112 mg of ((S-1-NEA)I), and 60 mg of methylamine hydroiodide (MAI). The resulting mixture was stirred at 70°C for 1 hour to prepare a solution containing the film raw materials. Then, spin coating was performed using the same procedure as in Example 1, followed by heating (100°C, 30 minutes) to obtain a (S-1-NEA)PbI3 film.

[0113] (Comparative Example 6)

[0114] By mixing 1 g of racemic DL-1-(1-naphthyl)ethylamine (rac-1-NEA) and 500 μL of hydrogen iodide (HI) and stirring at 0°C for 2 hours, 2.8 g of DL-1-(1-naphthyl)ethylamine hydrobromide ((rac-1-NEA)I) was obtained. Next, using 500 μL of dimethylformamide (DMF) as a solvent, 230 mg of lead iodide (PbI2), 112 mg of ((rac-1-NEA)I), and 60 mg of methylamine hydroiodide (MAI) were mixed, and the resulting mixture was stirred at 70°C for 1 hour to prepare a solution containing the film raw material. Then, spin-coating and subsequent heating (100°C, 30 minutes) were performed as in Example 1 to obtain a film of (rac-1-NEA)PbI3.

[0115] (Comparative Example 7)

[0116] The film was prepared in the same manner as in Example 1, except that methylaminohydroiodic acid was not used.

[0117] (Comparative Example 8)

[0118] The film was prepared in the same manner as in Example 4, except that methylaminohydroiodic acid was not used.

[0119] (Comparative Example 9)

[0120] The film was prepared in the same manner as in Example 5, except that methylaminohydroiodic acid was not used.

[0121] (Surface roughness measurement)

[0122] Atomic force microscopy (AFM) measurements were performed on Examples 1, 2, 4, and 5, and Comparative Examples 3, 6, to 9. The AFM was performed using a Shimadzu SPM-9700 (Si-made dynamic mode cantilever) in dynamic mode. The arithmetic mean roughness Ra was obtained from the observed images.

[0123] (XRD measurement)

[0124] For Examples 1, 2, 4, and 5, and Comparative Examples 3, 6, to 9, an X-ray diffraction apparatus (Bruker AXS D8 DISCOVER) was used to measure the X-ray diffraction patterns of each thin film at room temperature. During this measurement, a CuKα X-ray source was used, and an X-ray collimator was used. The detector used was a two-dimensional detector (VANTEC-500). The tube voltage and tube current were set to 40kV and 40mA, respectively. For the measurement conditions, ω was set to 1°, 2θ to 10°, and the cumulative time to 300 seconds.

[0125] (Optical Absorption Spectroscopy Measurement)

[0126] For Examples 1, 2, 4 and 5, and Comparative Examples 3, 6 to 9, the light absorption spectra of each thin film were measured using a UV-Vis spectrophotometer (J-1500 manufactured by Japan Spectrophotometer Co., Ltd.).

[0127] (Circular polarization dichroism spectroscopy determination)

[0128] For Examples 1, 2, 4 and 5, and Comparative Examples 3, 6 to 9, circular dichroism spectra of each thin film were measured using a circular dichroism spectrometer (J-1500 manufactured by Japan Spectrophotometer Co., Ltd.).

[0129] (Measurement of photocurrent and dark current characteristics)

[0130] Under the same conditions as in Examples 1 and 4, a thin film was formed on a substrate (Geomatec high-durability glass with a transparent conductive film) with a negative electrode layer deposited by sputtering or vacuum evaporation. Then, a positive electrode layer (silver, 80-100 nm thick) was formed on the opposite side in the thickness direction by sputtering or vacuum evaporation. The current flowing through the thin film was measured using a Keithley Digital Source Gauge 2450 when a voltage was applied between the positive and negative electrode layers and light (right-hand circularly polarized light and left-hand circularly polarized light) was irradiated onto the film. During irradiation, light obtained by spectroscopy using a Max350 xenon light source manufactured by Asahi Spectrophotometer (CMS-100) was used. The irradiation intensity was set to 1 mW / cm². 2The irradiated light is made into circularly polarized light using a linear polarizer and a quarter-wave plate (manufactured by THORLABS, Japan).

[0131] (Switch characteristic measurement)

[0132] For the samples with positive and negative electrode layers formed above, light (right-hand circularly polarized light and left-hand circularly polarized light) was irradiated at certain intervals to measure the switching characteristics.

[0133] The XRD analysis results of the thin films obtained in Examples 1, 2, and 3 are shown below. Figure 5 . Figure 5 The horizontal axis represents the diffraction angle. Figure 5 The vertical axis represents the diffraction intensity. Figure 5 (a) shows the measurement results of the thin film in Example 1. Figure 5 (b) shows the results of the film in Example 2. Figure 5 (c) shows the results for the thin film of Comparative Example 3. Any thin film from Examples 1, 2, and 3 exhibits periodic diffraction patterns corresponding to the (002), (004), (006), (008), and (0010) planes at 5.83, 11.7, 17.6, 23.5, and 29.5°. The space group of this thin film crystal, under Bragg reflection conditions (2dsinθ = nλ), has a crystal plane spacing of... That is, it can be known that in the state where there are chiral molecules between the inorganic layers formed by perovskite-type materials, with The spacing forms layered compounds.

[0134] The XRD results of the films obtained in Examples 4, 5, and Comparative Example 6 are shown below. Figure 6 . Figure 6 The horizontal axis represents the diffraction angle. Figure 6 The vertical axis represents the diffraction intensity. Figure 6 (a) shows the measurement results of the thin film in Example 4. Figure 6 (b) shows the results of the film in Example 5. Figure 6 (c) shows the results for the thin film of Comparative Example 6. Any thin film from Examples 4, 5, and 6 exhibits diffraction patterns at 6.84, 10.2, 11.3, 13.2, 13.7, and 24.3° corresponding to the (002), (011), (102), (110), (004), and (013) planes, indicating a crystal structure belonging to the chiral space group (P212121). Within the crystal, adjacent octahedral structures (PbI6) 4- There is a common surface, forming a one-dimensional chain. It can be seen that by enclosing this one-dimensional chain with 1-NEA, a helical structure is induced in the chain.

[0135] The XRD results of the films of Example 1 and Example 4 obtained using a two-dimensional detector are shown below. Figure 7 .insert Figure 7 (a) and Figure 7 Figure (b) shows the orientation distribution of the (002) facet. It can be seen that the (002) facet of the film of Example 1 is strongly oriented in the out-of-plane direction. Figure 7 (a)). That is, it means that the inorganic layer formed by perovskite is stacked parallel to the substrate. The film of Example 4 shows a peak of the (002) plane at the exact midpoint between the out-of-plane and in-plane directions. Figure 7 (b)). This means that the chains formed by perovskite are tilted in orientation.

[0136] The results of circularly polarized dichroic spectra (CD spectra) measurements of the thin films of Examples 1, 2, and 3 are shown below. Figure 8 (a) in the middle. Figure 8 In (a), the horizontal axis represents the wavelength. Figure 8 In (a), the vertical axis represents the CD signal intensity (CD[mdeg] = 32980 × Δ absorbance (the difference in absorption intensity between left and right circularly polarized light)). Figure 8 In (a), the dashed line represents the CD spectrum of Example 1, the dotted line represents the CD spectrum of Example 2, and the solid line represents the CD spectrum of Comparative Example 3. The thin film of Example 1 exhibits a CD signal of -56 mdeg at 488 nm. That is, the thin film of Example 1 shows strong absorption of right-circularly polarized light compared to left-circularly polarized light. The thin film of Example 2 shows a CD signal in the opposite direction, indicating strong absorption of left-circularly polarized light. Since the racemic thin film of Comparative Example 3 does not show a CD signal, circularly polarized light cannot be identified. The anisotropy factor (g) for identifying the circularly polarized light of a thin film with a two-dimensional structure is... CD The value of g is 0.003. CD The value is an order of magnitude larger than the gCD of typical organic chiral molecules.

[0137] The light absorption spectra of the thin films from Examples 1, 2, and 3 are shown below. Figure 8 (b) in the middle. Figure 8 In (b), the horizontal axis represents the wavelength. Figure 8 In (b), the vertical axis represents absorbance. Figure 8 In (b), the dashed line represents the light absorption spectrum of Example 1, and the dotted line represents the light absorption spectrum of Example 2. The films of Examples 1 and 2 exhibit a peak at 488 nm. The absorption intensity per unit thickness of the film of Example 1 is 89,286 cm⁻¹. -1 The absorption intensity per unit thickness of the film in Example 2 is 96,7517 cm⁻¹. -1It should be noted that the light absorption spectrum of Comparative Example 3 is the same as that of Examples 1 and 2.

[0138] The light absorption and circular polarization dichroism (CD) spectra of the thin films of Examples 4, 5, and Comparative Example 6 are shown below. Figure 9 (a) in the middle. Figure 9 In (a), the horizontal axis represents the wavelength. Figure 9 In (a), the vertical axis represents the CD signal intensity (CD[mdeg] = 32980 × Δ absorbance (the difference in absorption intensity between left and right circularly polarized light)). Figure 9 In (a), the dashed line represents the CD spectrum of Example 4, the dotted line represents the CD spectrum of Example 5, and the solid line represents the CD spectrum of Comparative Example 6. The film of Example 4 exhibits a CD signal of +3200 mdeg at 395 nm. That is, the film of Example 4 shows strong absorption of left-circularly polarized light compared to right-circularly polarized light. The film of Example 5 shows a CD signal in the opposite direction and strong absorption of left-circularly polarized light. Since the racemic film of Comparative Example 6 does not show a CD signal, circularly polarized light cannot be identified. Incidentally, the anisotropy factor (g) for identifying circularly polarized light... CD The naphthalene skeleton with two aromatic rings is larger than that of a two-dimensional structure and larger than that of a one-dimensional structure using phenylethylamine. This means that the naphthalene skeleton with two aromatic rings can induce the helicity of the one-dimensional structure more strongly than that of the benzene ring.

[0139] Furthermore, due to the g-structures of known layered structures described, for example, in J. Am. Chem. Soc. 2020, 142, 4206-4212, etc. CD The value is below 0.002, therefore it can be confirmed that the film of the present invention has excellent g-value. CD value.

[0140] The light absorption spectra of the thin films from Examples 4, 5, and Comparative Example 6 are shown below. Figure 9 (b) in the middle. Figure 9 In (b), the horizontal axis represents the wavelength. Figure 9 In (b), the vertical axis represents absorbance. Figure 9 In (b), the dashed line represents the light absorption spectrum of Example 4, and the dotted line represents the light absorption spectrum of Example 5. The films of Examples 4 and 5 exhibit a peak at 395 nm. The absorption intensity per unit thickness of the film of Example 4 is 127,273 cm⁻¹. -1 The absorption intensity per unit thickness of the film in Example 5 is 120,780 cm⁻¹. -1 It should be noted that the light absorption spectrum of Comparative Example 6 is the same as that of Examples 4 and 5.

[0141] The results of circularly polarized dichroic spectra (CD spectra) measurements of the thin films of Comparative Examples 8 and 9 are shown below. Figure 10 (a) in the middle. Figure 10 In (a), the horizontal axis represents the wavelength. Figure 10 In (b), the vertical axis represents the CD signal intensity (CD[mdeg] = 32980 × Δ absorbance (the difference in absorption intensity between left and right circularly polarized light)). Figure 10 In (a), the dashed line represents the CD spectrum of Comparative Example 8, and the dotted line represents the CD spectrum of Comparative Example 9. The CD signals of the films of Comparative Examples 8 and 9 are an order of magnitude smaller than those of Examples 4 and 5. This result implies that organohalides strongly influence the formation of one-dimensional helical structures.

[0142] The light absorption spectra of the thin films of Comparative Examples 8 and 9 are shown below. Figure 9 (b) in the middle. Figure 9 In (b), the horizontal axis represents the wavelength. Figure 9 In (b), the vertical axis represents absorbance. Figure 9 In (b), the dashed line represents the light absorption spectrum of Comparative Example 8, and the dotted line represents the light absorption spectrum of Comparative Example 9. The films of Examples 4 and 5 exhibit a peak at 395 nm. The absorption intensity per unit thickness of the film of Comparative Example 8 is 95,586 cm⁻¹. -1 The absorbance per unit thickness of the film in Comparative Example 9 is 96,086 cm⁻¹. -1 .

[0143] Figure 11 , 12 A graph is provided to illustrate the results of the photocurrent, dark current characteristics, and switching characteristics of the thin film obtained in Example 1.

[0144] Figure 11 The dashed line represents the current-voltage characteristics under right-handed circularly polarized light (RCP), the dotted line represents the current-voltage characteristics under left-handed circularly polarized light (LCP), and the solid line represents the current-voltage characteristics of the thin film under no light (darkness). Figure 11 The horizontal axis represents the applied voltage (V). Figure 11 The vertical axis represents the generated current density (A / cm). 2 ).

[0145] When any circularly polarized light is irradiated, a higher current (dark current) is generated compared to the case without irradiation. Furthermore, in Example 1, strong absorption of right-hand circularly polarized light is observed, therefore, irradiation with right-hand circularly polarized light generates a higher current than irradiation with left-hand circularly polarized light. It should be noted that in Example 2, strong absorption of left-hand circularly polarized light is observed, resulting in a higher current being generated when irradiated with left-hand circularly polarized light compared to irradiation with right-hand circularly polarized light. The extinction ratio of the two-dimensional structure (the sensitivity ratio of left-hand circularly polarized light to right-hand circularly polarized light, R) L / R R The value is 1.2. From the above results, it can be seen that the thin film of the present invention has sufficient sensitivity to circularly polarized light and can be used as a circularly polarized light detection element.

[0146] Figure 12 The dashed line represents the current switching characteristics of the thin film under the condition of applying a voltage of 0.5V and irradiating with right-hand circularly polarized light (RCP), while the dotted line represents the current switching characteristics of the thin film under the condition of irradiating with left-hand circularly polarized light (LCP). Figure 12 The horizontal axis represents the elapsed time (s). Figure 12 The vertical axis represents the generated current density (A / cm). 2 ).

[0147] Since the current increase becomes rapid when irradiated with any circularly polarized light, the thin film of the present invention exhibits excellent responsiveness when used as a circularly polarized light detection element. It should be noted that the same experiment was performed using the thin film of Comparative Example 7, and current leakage occurred. This is believed to be due to the large surface roughness (>30 nm) of the thin film prepared in Comparative Example 7, resulting in partial conduction between the positive and negative electrode layers. In other words, by preparing the thin film in the presence of an organic halide (methylamine), the surface roughness required for element fabrication can be suppressed, thereby suppressing current leakage.

[0148] The results of the photocurrent and switching characteristics measurements of the thin film in Example 4 are shown below. Figure 13 and Figure 14 .

[0149] Figure 13 The dashed line represents the current-voltage characteristics of the thin film when it is exposed to right-hand circularly polarized light (RCP), the dotted line represents the current-voltage characteristics of the thin film when it is exposed to left-hand circularly polarized light (LCP), and the solid line represents the current-voltage characteristics of the thin film when it is not exposed to light (darkness). Figure 13 The horizontal axis represents the applied voltage (V). Figure 14 The vertical axis represents the generated current density (A / cm). 2 ).

[0150] When any circularly polarized light is irradiated, a higher current (dark current) is generated compared to the case without irradiation. Furthermore, in Example 4, strong absorption is observed for left-handed circularly polarized light, therefore, irradiation with left-handed circularly polarized light results in a higher current than irradiation with right-handed circularly polarized light. It should be noted that in Example 5, strong absorption is observed for right-handed circularly polarized light, resulting in a higher current being generated when irradiated with right-handed circularly polarized light. The extinction ratio of a one-dimensional structure (the sensitivity ratio of left-handed circularly polarized light to right-handed circularly polarized light, R) L / R R The value is 25.4. From the above results, it can be seen that the thin film of the present invention has sufficient sensitivity to circularly polarized light and can be used as a circularly polarized light detection element.

[0151] Figure 14 The dashed line represents the current switching characteristics of the thin film when the applied voltage is set to 0.5V and it is irradiated with right-hand circularly polarized light (RCP), while the dotted line represents the current switching characteristics of the thin film when it is irradiated with left-hand circularly polarized light (LCP). Figure 14 The horizontal axis represents the elapsed time (s). Figure 14 The vertical axis represents the generated current density (A / cm). 2 ).

[0152] Since the current increases sharply when irradiated with any circularly polarized light, the thin film of the present invention exhibits excellent responsiveness when used as a circularly polarized light detection element.

[0153] Explanation of reference numerals in the attached figures

[0154] 100, 200···Film

[0155] 101, 201... Perovskite-type substances

[0156] 102······Inorganic layer

[0157] 103, 203... chiral molecules

[0158] 104, 204...Boundary section

[0159] 105, 205... Organic layer

[0160] 106, 206... Negative electrode layer

[0161] 107, 207... Positive electrode layer

[0162] 108, 208... Negative electrode side adhesive layer

[0163] 109, 209... Positive electrode side bonding layer

[0164] 110, 220... Circularly polarized light detection elements

[0165] 202·······Inorganic Chain

Claims

1. A thin film, characterized in that, It is a thin film for circularly polarized light detection, the thin film comprising: Multiple inorganic chains forming a chain-like structure from perovskite-type materials; and A chiral molecule, which is contained in at least a portion of the boundary between adjacent inorganic chains. The chiral molecule contains either an S-type chiral molecule or an R-type chiral molecule, or the proportion of either an S-type chiral molecule or an R-type chiral molecule is higher than the proportion of the other. The crystal structure of the perovskite-type material is oriented in a specified direction. The absorption intensity per unit thickness of the film is 50,000 cm⁻¹. -1 Above 500,000cm -1 the following, The perovskite-type substance and the chiral molecule together form a compound ABX3 composed of three ions, A, B, and X. The ions B and X form multiple unit cells with octahedral structures, and the octahedral structures of adjacent unit cells share a common face. The chiral molecule is an aromatic compound that is bonded to the perovskite-type material by functional groups covalently bonded to the chiral carbon atoms constituting the chiral molecule, and has two or more benzene rings forming the rings of the aromatic compound, wherein the aromatic compound has an aromatic ring structure that shares one side of the benzene ring.

2. The thin film as described in claim 1, characterized in that, The aromatic compound has a naphthalene ring or an anthracene ring.

3. The thin film as described in claim 1, characterized in that, The surface roughness Ra is between 1 nm and 30 nm.

4. The film according to any one of claims 1 to 3, characterized in that, It is formed by the chiral molecules forming an organic layer at the boundary and the chiral molecules surrounding the inorganic chain.

5. The film according to any one of claims 1 to 3, characterized in that, It is formed by the chiral molecules forming an organic layer at the boundary and the chiral molecules surrounding the inorganic chain. The functional group is a substituent that can carry an electric charge. This substituent forms a bond with the perovskite-type substance through a halide ion, thereby fixing the chiral molecule to the inorganic chain.

6. The film according to any one of claims 1 to 3, characterized in that, Ion A is an aromatic compound containing ethylammonium ions, ion B is a lead ion or a tin ion, and ion X is a halide ion.

7. The film according to any one of claims 1 to 3, characterized in that, Ion A is an aromatic compound containing ethylammonium ions, ion B is a lead ion, ion X is an iodide ion, and the chiral molecule is less than 0.75 molecules relative to 1 molecule of lead ion.

8. A method for manufacturing a thin film, as described in any one of claims 1 to 7, comprising: The first step involves dissolving the precursor of the perovskite-type material, the chiral molecule, and the organohalide that can sublimate upon heating and react with a portion of the constituent elements of the perovskite-type material, in a solvent. In the second step, the solution obtained in the first step is coated onto a substrate using a spin coating method to form a pre-treatment coating film on the substrate; and The third step involves heating the pre-treatment coating to sublimate the organic halides contained in it, thereby obtaining the thin film composed of a polycrystalline inorganic layer and chiral molecules distributed therebetween.

9. The method for manufacturing a thin film as described in claim 8, characterized in that, The precursor of the perovskite-type material is lead halide. The organohalide is a halomethylammonium or a formamidinium halide.

10. The method for manufacturing a thin film as described in claim 9, characterized in that, The halogen atoms contained in the lead halide and the organohalides are any one of bromine, chlorine, or iodine atoms.

11. The method for manufacturing a thin film as described in claim 9, characterized in that, The halogen atoms contained in the lead halide and the organohalides are iodine atoms.

12. A circularly polarized light detection element, characterized in that, The thin film comprising any one of claims 1 to 7.

13. The circularly polarized light detection element as described in claim 12, characterized in that, It is formed by stacking a negative electrode layer, the thin film, and a positive electrode layer in sequence, wherein at least one of the negative electrode layer and the positive electrode layer is transparent.

14. A device, characterized in that, It is composed of the circularly polarized light detection element as described in claim 12.

15. A thin film, characterized in that, It is a chiral thin film formed from perovskite-type materials. The thin film comprises: a plurality of inorganic chains constituting a chain-like structure; and chiral molecules contained in at least a portion of the boundaries between adjacent inorganic chains, wherein the chiral molecules are chiral molecules containing only one of S-type or R-type chiral molecules, or chiral molecules containing one of S-type or R-type chiral molecules in a higher proportion than the other, and the crystal structure of the perovskite material is oriented along a predetermined direction. The absorption intensity per unit thickness of the film is 50,000 cm⁻¹. -1 Above 500,000cm -1 the following, The perovskite-type substance and the chiral molecule together form a compound ABX3 composed of three ions, A, B, and X. The ions B and X form multiple unit cells with octahedral structures, and the octahedral structures of adjacent unit cells share a common face. The chiral molecule is an aromatic compound that is bonded to the perovskite-type material by functional groups covalently bonded to the chiral carbon atoms constituting the chiral molecule, and has two or more benzene rings forming the rings of the aromatic compound, wherein the aromatic compound has an aromatic ring structure that shares one side of the benzene ring.

16. The thin film as claimed in claim 15, characterized in that, The aromatic compound has a naphthalene ring or an anthracene ring.

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