Rhodanine group-introduced heterocyclic compound, and organic semiconductor and photoelectric conversion device comprising same

Abstract

The present invention relates to a novel-structured rhodamine group-introduced heterocyclic compound, and an organic semiconductor and a photoelectric conversion device comprising same. Specifically, the present invention provides a compound represented by chemical formula 1. [Chemical formula 1] (In chemical formula 1, X1 and X2 are each independently -O-, -S-, or -Se-; R1, R2, and R5 are each independently (C1-C12)alkyl or (C1-C12)deuteroalkyl; R1 and R2 may be linked to (C1-C12)alkylene or (C1-C12)deuteroalkylene to form a fused ring; R3 and R4 are each independently hydrogen, deuterium, (C1-C7)alkyl, or (C1-C7)deuteroalkyl, or may be linked to an adjacent substituent to form a ring; and a and b are each independently an integer of 1 to 4.)

Description

Heterocyclic compound with rhodanine group introduced, organic semiconductor and photoelectric conversion device containing the same

[0001] The present disclosure relates to a heterocyclic compound having a novel rhodanine group structure, an organic semiconductor, and a photoelectric conversion device comprising the same.

[0002]

[0003] Organic semiconductors are attracting attention as next-generation materials that can replace conventional inorganic semiconductors due to their various advantages, including flexibility, lightweight properties, and easy film formation. Organic semiconductor materials are being applied to a wide range of electronic devices. In particular, active research is being conducted to utilize the optical properties of organic semiconductor materials to apply them to photoelectric conversion devices such as organic solar cells (OPVs), organic photodiodes (OPDs), and photodetectors.

[0004] Until now, organic semiconductors have had limitations in terms of relatively low energy conversion efficiency and durability, and as the performance requirements for photoelectric conversion devices have become increasingly sophisticated, the development of new organic semiconductor materials that can satisfy these requirements is required.

[0005] In particular, since photodiodes using organic materials do not require separate color filters, their application fields are expanding beyond displays, cameras, and optical communications to iris recognition sensors, heartbeat and pulse detection sensors, and other biosignal detection sensors. Therefore, there is a need to develop an electron acceptor that is easy to apply to the solution process and has excellent photoelectric conversion efficiency and selectivity.

[0006]

[0007] One aspect of the present invention is to provide a compound having a novel structure that can be usefully used as an electron acceptor material for a photoelectric conversion device and a method for producing the same.

[0008] Another aspect of the present invention is to provide a photoelectric conversion device, for example, a green photodiode, which can simultaneously satisfy excellent wavelength selectivity, energy conversion efficiency, and durability by employing an organic semiconductor including the compound.

[0009]

[0010] One aspect of the present invention provides a compound represented by the following chemical formula 1.

[0011] [Chemical Formula 1]

[0012]

[0013] (In the above chemical formula 1,

[0014] X1 and X2 are each independently -O-, -S- or -Se-;

[0015] R1, R2 and R5 are each independently (C1-C12)alkyl or (C1-C12)deuteroalkyl, and R1 and R2 can be connected to (C1-C12)alkylene or (C1-C12)deuteroalkylene to form a fused ring;

[0016] R3 and R4 are each independently hydrogen, deuterium, (C1-C7)alkyl or (C1-C7)deuteroalkyl, or may be connected to an adjacent substituent to form a ring;

[0017] a and b are each independently integers from 1 to 4.)

[0018] According to one aspect, the compound may be represented by the following chemical formula 2 or 3.

[0019] [Chemical Formula 2]

[0020]

[0021] [Chemical Formula 3]

[0022]

[0023] (In the above chemical formulas 2 and 3,

[0024] R1, R2 and R5 are each independently (C1-C7)alkyl or (C1-C7)deuteroalkyl, and R1 and R2 can be connected to (C1-C7)alkylene or (C1-C7)deuteroalkylene to form a fused ring;

[0025] R3, R 4, R6 and R7 are each independently hydrogen, deuterium, (C1-C5)alkyl or (C1-C5)deuteroalkyl;

[0026] a to d are each independently integers from 1 to 4.)

[0027] According to one aspect, the compound may be represented by the following chemical formula 4.

[0028] [Chemical Formula 4]

[0029]

[0030] (In the above chemical formula 4,

[0031] R1, R2 and R5 are each independently (C1-C7)alkyl or (C1-C7)deuteroalkyl, and R1 and R2 can be connected to (C1-C7)alkylene or (C1-C7)deuteroalkylene to form a fused ring;

[0032] R3 and R4 are each independently hydrogen, deuterium, (C1-C5)alkyl or (C1-C5)deuteroalkyl.

[0033] The above R1 to R5 can each independently be CH3, CD3, CDH2 or CD2H.

[0034] According to one aspect, the compound may be represented by the following chemical formula 6 or 7.

[0035] [Chemical Formula 6]

[0036]

[0037] [Chemical Formula 7]

[0038]

[0039] The compound according to one aspect may be selected from the following structures.

[0040]

[0041]

[0042]

[0043]

[0044]

[0045] According to one aspect, the compound may absorb light in the green wavelength range.

[0046] According to one aspect, the compound may exhibit a maximum absorption wavelength in the range of 450 to 650 nm.

[0047] Another aspect of the present invention provides an organic semiconductor comprising the compound.

[0048] According to one aspect, the compound may be used as an electron acceptor of the organic semiconductor.

[0049] Another aspect of the present invention provides a photoelectric conversion device comprising the organic semiconductor.

[0050] According to one aspect, the photoelectric conversion element may include a first electrode; a second electrode positioned opposite the first electrode; and a photoactive layer positioned between the first electrode and the second electrode and including the organic semiconductor.

[0051] The above photoelectric conversion element may be an organic photodiode, an organic solar cell, an organic photodetector, an organic photosensor, or an organic light-emitting diode.

[0052] The above photoelectric conversion element may be a green photodiode.

[0053] Another aspect of the present invention provides an image sensor including the photoelectric conversion element.

[0054]

[0055] Compounds according to one aspect have optical properties such as a low energy gap and a high absorption coefficient, enabling them to achieve excellent photoelectric conversion efficiency. Furthermore, compounds according to one aspect have a maximum absorption peak in the green light wavelength range, and a narrow full width at half maximum at the maximum absorption wavelength, resulting in excellent green light selectivity and being useful as electron acceptor materials for photoelectric conversion devices, such as green photodiodes.

[0056] Furthermore, compounds according to one embodiment exhibit excellent solubility in organic solvents, facilitating solution processing, and exhibiting both superior chemical and thermal stability. In other words, photoelectric conversion devices employing compounds according to one embodiment, such as green photodiodes, not only exhibit superior photoelectric conversion efficiency and durability, but also eliminate the need for separate color filters, which can be highly advantageous for improved sensitivity, miniaturization, and high integration.

[0057]

[0058] Figure 1 is a UV absorption spectrum photograph of compound (1) of Example 1.

[0059] Figure 2 is a UV absorption spectrum photograph of compound (2) of Example 2.

[0060]

[0061] Unless otherwise defined herein, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0062] As used herein, the singular forms may be intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0063] Throughout this specification, the terms "comprises," "includes," "contains," or "has" a component, unless specifically stated to the contrary, do not exclude other components, but rather may include other components, and do not exclude additional unrecited elements, materials, or processes.

[0064] The numerical ranges used herein include the lower and upper limits and all values ​​within that range, increments logically derived from the shape and width of the defined range, all doubly defined values, and all possible combinations of the upper and lower limits of numerical ranges defined in different shapes. Unless otherwise specified herein, values ​​outside the defined range that may arise due to experimental error or rounding of values ​​are also included in the defined numerical range.

[0065] Unless otherwise specified herein, “about” may be considered a value within 30%, 25%, 20%, 15%, 10% or 5% of the stated value.

[0066] In this specification, “room temperature” means a temperature of 20±5℃.

[0067] In this specification, “CA-CB” means “having carbon number greater than or equal to A and less than or equal to B.”

[0068] As used herein, "alkyl" means a monovalent straight-chain or branched saturated hydrocarbon radical composed solely of carbon and hydrogen atoms. The alkyl may have 1 to 12 carbon atoms, 1 to 7 carbon atoms, 1 to 4 carbon atoms, or 1 to 4 carbon atoms. The alkyl includes, but is not limited to, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl, hexyl, ethylhexyl, and the like.

[0069] As used herein, “deuteroalkyl” means an alkyl radical in which one or more hydrogen atoms are replaced with deuterium (D), and examples of deuteroalkyl include, but are not limited to, -CH2D, -CHD2, -CD3, -CH2CD3, -CDHCD3, -CD2CD3, -CH(CD3)2, -CD(CHD2)2, and -CH(CH2D)(CD3).

[0070] Below, the present disclosure will be described in detail. However, this is merely exemplary and the present disclosure is not limited to the specific embodiments described as examples.

[0071] One aspect of the present invention provides a novel structural compound that can be usefully used as an electron acceptor material for a photoelectric conversion device and that satisfies wavelength selectivity, energy conversion efficiency, and durability. Specifically, the compound according to one aspect can be represented by the following chemical formula 1.

[0072] [Chemical Formula 1]

[0073]

[0074] In the above chemical formula 1,

[0075] X1 and X2 are each independently -O-, -S- or -Se-;

[0076] R1, R2 and R5 are each independently (C1-C12)alkyl or (C1-C12)deuteroalkyl, and R1 and R2 can be connected to (C1-C12)alkylene or (C1-C12)deuteroalkylene to form a fused ring;

[0077] R3 and R4 are each independently hydrogen, deuterium, (C1-C7)alkyl or (C1-C7)deuteroalkyl, or may be connected to an adjacent substituent to form a ring;

[0078] a and b are each independently an integer from 1 to 4.

[0079] Specifically, the compound according to one aspect can be represented by the following chemical formula 1-1 and can enable better electron transport.

[0080] [Chemical Formula 1-1]

[0081]

[0082] In the above chemical formula 1-1,

[0083] R1, R2 and R5 are each independently (C1-C12)alkyl or (C1-C12)deuteroalkyl, and R1 and R2 can be connected to (C1-C12)alkylene or (C1-C12)deuteroalkylene to form a fused ring;

[0084] R3 and R4 are each independently hydrogen, deuterium, (C1-C7)alkyl or (C1-C7)deuteroalkyl, or may be connected to an adjacent substituent to form a ring;

[0085] a and b are each independently an integer from 1 to 4.

[0086] The compound according to one aspect of the present invention not only exhibits improved charge mobility within the molecule by having an indeno-heteroarylene central structure, but also introduces an amine group including a rhodanine group and an aromatic ring simultaneously to control the energy levels of HOMO and LUMO, so that an organic semiconductor including this as an electron acceptor can realize excellent photoelectric conversion efficiency.

[0087] Specifically, the compound according to one aspect can be represented by the following chemical formula 2 or 3, and a higher light absorption effect can be expected due to the appropriate electron donor role of the amine group.

[0088] [Chemical Formula 2]

[0089]

[0090] [Chemical Formula 3]

[0091]

[0092] In the above chemical formulas 2 and 3,

[0093] R1, R2 and R5 are each independently (C1-C7)alkyl or (C1-C7)deuteroalkyl, and R1 and R2 can be connected to (C1-C7)alkylene or (C1-C7)deuteroalkylene to form a fused ring;

[0094] R3, R 4, R6 and R7 are each independently hydrogen, deuterium, (C1-C5)alkyl or (C1-C5)deuteroalkyl;

[0095] a to d are each independently integers from 1 to 4.

[0096] For example, R1, R2 and R5 may each independently be (C1-C3)alkyl or (C1-C3)deuteroalkyl.

[0097] For example, R1 and R2 are the same and may be (C1-C3)alkyl or (C1-C3)deuteroalkyl.

[0098] For example, R1 and R2 may be linked to (C1-C5)alkylene or (C1-C5)deuteroalkylene to form a fused ring.

[0099] For example, the above R3, R 4, R6 and R7 can each independently be hydrogen, deuterium, (C1-C3)alkyl or (C1-C3)deuteroalkyl.

[0100] For example, the above R3, R 4, R6 and R7 are each the same and may be hydrogen, deuterium, (C1-C3)alkyl or (C1-C3)deuteroalkyl.

[0101] For example, a to d may each independently be an integer from 1 to 3, or 1 or 2.

[0102] For example, a and b may be equal to each other and may be integers from 1 to 3, or may be 1 or 2.

[0103] For example, c and d are equal to each other and may be integers from 1 to 3, or 1 or 2.

[0104] Specifically, the compound according to one aspect can be represented by the following chemical formula 4.

[0105] [Chemical Formula 4]

[0106]

[0107] In the above chemical formula 4,

[0108] R1, R2 and R5 are each independently (C1-C7)alkyl or (C1-C7)deuteroalkyl, and R1 and R2 can be connected to (C1-C7)alkylene or (C1-C7)deuteroalkylene to form a fused ring;

[0109] R3 and R4 are each independently hydrogen, deuterium, (C1-C5)alkyl or (C1-C5)deuteroalkyl.

[0110] For example, R3 and R4 can each independently be hydrogen, deuterium, (C1-C3)alkyl, (C1-C3)deuteroalkyl or halogen.

[0111] For example, R1, R2 and R5 can independently be (C1-C3)alkyl or (C1-C3)deuteroalkyl, specifically CH3, CD3, CDH2 or CD2H.

[0112] For example, R1, R2 and R5 can be each independently (C1-C3)alkyl or (C1-C3)deuteroalkyl, specifically CH3, CD3, CDH2 or CD2H.

[0113] In the compound according to one aspect, R1 to R5 may each independently be CH3, CD3, CDH2 or CD2H.

[0114] Specifically, the compound according to one aspect may be represented by the following chemical formula 6 or 7.

[0115] [Chemical Formula 6]

[0116]

[0117] [Chemical Formula 7]

[0118]

[0119] Compounds according to one aspect may be selected from, but are not limited to, the structures below.

[0120]

[0121]

[0122]

[0123]

[0124]

[0125] According to one aspect, the compound can selectively absorb light in the green wavelength range due to its structural characteristics as described above. For example, the maximum absorption wavelength of the compound may be in the range of 450 to 650 nm, more specifically, in the range of 500 to 600 nm.

[0126] In addition, the compound according to one aspect can realize excellent photoelectric conversion efficiency because it has a low energy gap and a high absorption coefficient due to the structural features as described above.

[0127] That is, the compound according to one aspect can be usefully used as an organic semiconductor, especially an electron acceptor, of a photoelectric conversion device, and the photoelectric device employing the compound according to one aspect not only has excellent energy efficiency but also has excellent wavelength selectivity, does not require a separate color filter, and has the advantages of being advantageous in miniaturization and high integration.

[0128] Another aspect of the present invention provides an organic semiconductor and photoelectric conversion device comprising the compound.

[0129] Hereinafter, a photoelectric conversion device according to one embodiment will be described. However, it is to be understood that the photoelectric conversion device can be manufactured in a structure known in the art using a manufacturing method and materials common in the art, except that the photoactive layer includes a compound according to one embodiment.

[0130] The photoelectric conversion device according to one aspect is not limited to any device in which the compound of the present invention can be used, and may be, for example, an organic photodiode, an organic solar cell, an organic photodetector, an organic photosensor, or an organic light-emitting diode, preferably an organic photodiode, and more preferably a green photodiode.

[0131] The photoelectric conversion device according to one aspect may include the compound of the present invention in the photoactive layer.

[0132] The photoelectric conversion element according to one aspect may include a substrate; a first electrode; a photoactive layer; and a second electrode, and may further include a hole transport layer, an electron transport layer, etc.

[0133] Specifically, a photoelectric conversion element according to one aspect may include a substrate; a first electrode; a second electrode positioned opposite the first electrode; and an organic layer positioned between the first electrode and the second electrode. The organic layer includes a photoactive layer and may have a single-layer structure or a multilayer structure of two or more layers. When the organic layer has a multilayer structure, for example, it may have a structure in which a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, etc. are laminated.

[0134] The above organic layer includes a photoactive layer, and the photoactive layer may include an electron acceptor and an electron donor, and a compound according to one embodiment may be included as an electron acceptor, and a photoelectric conversion device employing the same may have improved photoelectric conversion efficiency.

[0135] The substrate may be made of a flexible and transparent material such as glass, a quartz plate, or a plastic including PET (polyethylene terephthalate), PEN (polyethylene naphthelate), PP (polyperopylene), PI (polyimide), PC (polycarbornate), PS (polystylene), POM (polyoxyethlene), AS resin (acrylonitrile styrene copolymer), ABS resin (acrylonitrile butadiene styrene copolymer), and TAC (Triacetyl cellulose).

[0136] In addition, the first electrode may be formed by applying a transparent electrode material to one surface of the substrate or coating it in the form of a film using sputtering, E-Beam, thermal deposition, spin coating, screen printing, inkjet printing, doctor blade, or gravure printing. The first electrode is a portion that functions as an anode, and any material having transparency and conductivity and a higher work function than the second electrode described later may be used. For example, there are ITO (indium tin oxide), gold, silver, fluorine doped tin oxide (FTO), aluminum doped zinc oxide (AZO), IZO (indium zinc oxide), ZnO-Ga2O3, ZnO-Al2O3, and ATO (antimony tin oxide, SnO2-Sb2O3), and it is preferably good to use ITO.

[0137] The photoactive layer is composed of a mixture of an electron acceptor and an electron donor, and can provide a photovoltaic effect through very fast charge transfer and separation phenomena. The compound of the present invention can be included as an electron acceptor, and the mixing amount thereof can be appropriately adjusted depending on the application. In addition, the compound of the present invention can be dissolved in an organic solvent and used as an electron acceptor material of the photoactive layer with a thickness of 60 mm or more, preferably 60 to 120 nm. Also, examples of the electron donor include PBDB-T (poly[(2,6-(4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)-benzo[1,2-b:4,5-b']dithiophene))-alt-(5,5-(1',3'-di-2-thienyl-5',7'-bis(2-ethylhexyl)benzo[1',2'-c:4',5'-c']dithiophene-4,8-dione))]), PBDB-TS (poly[(2,6-(4,8-bis(5-(2-ethylhexylthio)thiophen-2-yl)-benzo[1,2-b:4,5-b']dithiophene))-alt-(5,5- (1',3'-di-2-thienyl-5',7'-bis(2-ethylhexyl)benzo[1',2'-c:4',5'-c']dithiophene-4,8-dione))]), PBDB-T-SF (Poly[(2,6-(4,8-bis(5-(2-ethylhexylthio)-4-fluorothiophen-2-yl)-benzo[1,2-b:4,5-b']-dithiophene))-a lt-(5,5-(1',3'-di-2-thienyl-5',7'-bis(2-ethylhexyl)benzo[1',2'-c:4',5'-c']dithiophene-4,8-dione)]), PBDB-T-2F (poly[(2,6-(4,8-bis(5-(2-ethylhexyl)-4-fluorothiophen-2-yl)-benzo[1,2-b:4,5-b']dithiophene))-alt- (5,5-(1',3'-di-2-thienyl-5',7'-bis(2-ethylhexyl)benzo[1',2'-c:4',5'-c']dithiophene-4,8-dione)]), PBDTTT-CT (poly[(4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)-benzo[1,2-b;4,5-b']dithiophene)-2,6-diyl-alt-(4-(2-ethylhexanoyl)-thieno[3,4-b]thiophene))-2,6-diyl]), PBDTTT-CF (poly[1-(6-{4,8-bis[(2-ethylhexyl)oxy]-6-methylbenzo[1,2-b:4,5-b']dithiophen-2-yl}-3-fluoro-4-methylthieno[3,4-b]thiophen-2-yl)-1-octanone]), J51 (Poly[(5,6-difluoro-2-octyl-2H-benzotriazole-4,7-diyl)-2,5-thiophenediyl[4,8-bis[5-(2-hexyldecyl)-2-thienyl]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl]-2,5-thiophenediyl]), PBDTT-DPP (poly{2,6'-4,8-di(5-ethylhexylthienyl)benzo[1,2-b;3,4-b]dithiophene-alt-5-dibutyloctyl-3,6-bis(5-bromothiophen-2-yl)pyrrolo[3,4-c]pyrrole-1,4-dione}, P3HT (poly(3-hexylthiophene)), PCDTBT (poly[N-9'-heptadecanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)]), etc. The electron donor and the compound of the present invention are mixed in a weight ratio of 1:0.1 to 1:1 and the solution dissolved in an organic solvent is spin-coated, spray-coated, screen-printed, etc.A photoactive layer can be formed by a method such as a doctor blade method. The organic solvent may be a single organic solvent or two or more organic solvents having different boiling points, and specifically, may be at least one organic solvent selected from the group consisting of chlorobenzene, acetone, methanol, tetrahydrofuran, toluene, xylene, tetralin, 1,2-dichlorobenzene, and chloroform.

[0138] The photoactive layer uses the compound according to the present invention as an electron acceptor, and no change in its state is observed even under a wide range of temperature conditions, so that it can have excellent performance and morphology. In addition, in order to control the morphology and crystallinity of the photoactive layer, additional additives may be further included. Examples of the additives include 1,8-diiodooctane (DIO:1,8- diiodooctane), 1-chloronaphthalene (1-CN:1-chloronaphthalene), diphenylether (DPE:diphenylether), octane dithiol, tetrabromothiophene, etc., and they can be appropriately mixed and used depending on the intended use.

[0139] In addition, the second electrode can be deposited using a thermal evaporator in a state where the electron transport layer is introduced. At this time, usable electrode materials may be selected from lithium fluoride / aluminum, lithium fluoride / calcium / aluminum, aluminum / calcium, barium fluoride / aluminum, barium fluoride / barium / aluminum, barium / aluminum, aluminum, gold, silver, magnesium:silver, and lithium:aluminum, and it is preferable to use an electrode manufactured with a silver, aluminum, aluminum / calcium, or barium fluoride / barium / aluminum structure.

[0140] In addition, materials for the electron transport layer and hole transport layer may be used differently from the general types of electron transport layer and hole transport layer. An example of an electron transport layer material is TiO x, ZnO, TiO2, ZrO2, MgO, HfO2, etc., and examples of hole transport layer materials include metal oxides such as NiO, Ta2O3, MoO3, Ru2O3, etc. In addition, in addition to the above-described metal oxides, it goes without saying that an organic conjugated polymer electrolyte having a cation or an anion can be used as an electron transport layer or hole transport layer material.

[0141] Another aspect of the present invention provides an image sensor including the photoelectric conversion element, for example, a green photodiode.

[0142] Photodiodes are a key component of image sensors, and must have high sensitivity to red, green, and blue colors individually to reproduce high-resolution images. Conventional silicon-based semiconductors lack wavelength selectivity, requiring separate color filters. This makes it difficult to absorb light over a wide range of wavelengths, leading to high production costs and difficulties in miniaturization. The compound according to the present invention exhibits excellent selectivity for green light, enabling it to simultaneously replace both photodiodes and color filters. Furthermore, it exhibits a low energy gap and high absorption coefficient, enabling it to achieve excellent photoelectric conversion efficiency.

[0143]

[0144] Hereinafter, the above-described implementation examples will be described in more detail through examples. However, the following examples are for illustrative purposes only and do not limit the scope of the rights.

[0145] [Example 1] Preparation of Compound 1

[0146]

[0147] Step 1: Preparation of compound (1)-B

[0148] Compound (1)-A 9.10 g (32.59 mmol) synthesized with reference to the known literature (J. Phys. Chem. C 2011, 115, 45, 22640-22646), di-p-tolylamine 7.68 g (39.11 mmol) and sodium tert-butoxide (Na(Ot-bu)) 6.49 g (48.89 mmol) were dissolved in 180 mL of toluene under nitrogen. After nitrogen purging for 10 minutes, 1.5 g (1.15 mmol) of Pd2(dba)3 and 1.6 ml (2 M in toluene) of tri-tert-butylphosphine (P(t-bu)3) were added. After heating at 120°C for more than 4 hours, the mixture was poured into water, extracted with dichloromethane (DCM), and the organic layer was dried over MgSO4, filtered, and purified by silica gel column chromatography using dichloromethane / hexane as a mobile phase to obtain compound 1-(B) as a white solid (9.78 g, 76% yield).

[0149] 1 H-NMR (300 MHz, CD2Cl2): δ 7.29 - 7.26 (m, 2H), 7.15 - 6.99 (m, 10H), 6.91 - 6.88 (m, 1H), 2.34 (s, 6H), 1.41 (s, 6H).

[0150] Step 2: Preparation of compound (1)-C

[0151] 4.13 ml (44.25 mmol) of dimethylformamide (DMF) was added dropwise under nitrogen in a 3-neck round bottom flask, and then 4.13 ml (44.25 mmol) of POCl3 was dropped at 0°C. 7 g (17.7 mmol) of the compound 1-(B) obtained above was dissolved in 210 ml of 1,2-dichloroethane and added. The mixture was heated at 80°C for more than 4 hours, poured into 500 ml (1 M) of sodium acetate, stirred at room temperature for 1 hour, extracted with DCM, and the organic layer was dried over MgSO4, filtered, and purified by silica gel column chromatography using ethyl acetate / hexane as a mobile phase to obtain compound (1)-C as a yellow solid (6.75 g, 90%). yield).

[0152] 1 H-NMR (300 MHz, CD2Cl2): δ 9.73 (s, 1H), 7.56 (s, 1H), 7.29 - 7.26 (d, J = 8.3 Hz, 1H), 7.03 - 6.91 (m, 9H), 6.81 - 6.78 (m, 2H), 2.24 (s, 6H), 1.31 (s, 6H).

[0153] Step 3: Preparation of compound (1)

[0154] Compound (1)-C 1.5 g (3.53 mmol) obtained above and 1H-indene-1,3(2H)-dione 0.77 g (5.29 mmol) were dissolved in 75 ml of ethanol under a nitrogen stream. Piperidine was added dropwise 3 times, and the mixture was heated at 70°C overnight. After cooling the mixture to room temperature, it was filtered with ethanol to filter the solid material, and the obtained solid material was purified by silica gel column chromatography using dichloromethane / hexane as a mobile phase, and diethyl ether was added dropwise, followed by filtration to obtain compound (1) (0.9 g, 46% yield).

[0155] 1 H NMR (300 MHz, CD2Cl2): δ 7.923 (s, 1H), 7.38 - 7.36 (d, J = 7.6 Hz, 2H), 7.06 - 7.03 (m, 4H), 6.93 - 6.89 (m, 1H), 4.24 - 4.17 (m, 2H), 2.36 (s, 6H), 1.43 (s, 6H), 1.33 - 1.28 (m, 3H).

[0156]

[0157] [Example 2] Preparation of compound (2)

[0158]

[0159] Compound (2) was obtained (70% yield) by performing the same procedure as in step 1 of Example 1 except that 2-(A) was used instead of (1)-A.

[0160] 1H NMR (300 MHz, CD2Cl2): δ = 7.84-7.81 (d, 2H), 7.72 (s, 1H) 7.52-7.49 (d, 1H), 7.44-7.39 (t, 2H), 7.24-7.18 (t, 2H). 6.99-6.82 (m,11H), 6.75 (s, 1H), 6.39-6.38 (d, 1H), 4.19-4.12 (m, 2H), 2.27 (s, 6H), 1.29-1.24 (t, 3H).

[0161]

[0162] <Organic photodiode manufacturing>

[0163] [Example 3]

[0164] A glass substrate coated with ITO (Indium Tin Oxide), which is a positive transparent electrode (first electrode), was immersed in deionized water containing a cleaning solution, washed in an ultrasonic cleaner for 15 minutes, and then washed three times each with deionized water, acetone, and isopropyl alcohol (IPA), and dried in an oven at 80°C for 5 hours. The ITO glass substrate washed as described above was treated with UV / ozone for 15 minutes, and then spin-coated with PEDOT:PSS (Poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate)), and heat-treated on a hot plate at 150°C for 15 minutes to form a 30 nm thick PEDOT:PSS layer.

[0165] After transferring the device to an argon-filled glove box, the compound (1) obtained in Example 1 as an electron acceptor and PM6 as an electron donor were dissolved in chloroform (CF) at a weight ratio of 1:1 to a concentration of 17 mg / mL. Thereafter, 1-CN (1-chloronaphthalene) was added at 0.5 v / v% and stirred to prepare an organic semiconductor solution.

[0166] The organic semiconductor solution was filtered through a 0.45 μm (PTFE) syringe filter, spin-coated on the PEDOT:PSS layer, and annealed at 120°C for 10 minutes to produce a 100 nm thick photoactive layer. Afterwards, PNDITF3N-Br was dissolved in methanol (MeOH) at a concentration of 1 mg / mL as an electron transport layer and spin-coated to a thickness of 3 nm on the photoactive layer. Subsequently, a 3×10 -6 An organic photodiode having a conventional structure of [Glass / ITO / PEDOT:PSS / photoactive layer (compound of the present invention: PM6) / PDNITF3B-Br / Ag] was fabricated by depositing a 100 nm thick Ag electrode as the top electrode under a vacuum of 10 torr.

[0167] [Example 4]

[0168] The same procedure was followed as in Example 3 above, except that compound (2) was used instead of compound (1) as an electron acceptor.

[0169]

[0170] <Evaluation example>

[0171] Evaluation 1. Evaluation of optical and electrochemical properties

[0172] The optical absorption regions of compounds (1) and (2) prepared in the above Examples 1 and 2 were measured in a solution state (CHCl3) and a film state, and the respective results are shown in Figures 1 and 2. In addition, the optical properties of compounds (1) and (2) are shown in Table 1 below, and the band gap (Eg) and full width at half maximum (FWHM) were obtained from the UV absorption wavelength in the film state.

[0173] UV-Sol.λ max (nm)UV-filmλ max (nm)UV-Filmλ edge (nm)E g (eV)FWHM-Film(nm)ε(mol-1 cm -1 L) Example 15525616551.89161ε 699 =104,600ε 707 =26,300 Example 25505726551.89162ε 550 =51,369ε 572 =14,437

[0174] Referring to Table 1, it can be seen that the compounds according to the embodiments of the present invention not only facilitate solution processing, but also exhibit excellent photoelectric conversion efficiency and green light selectivity. Specifically, the compounds according to the embodiments have a low energy gap and a high molar extinction coefficient (ε), so that they can achieve excellent photoelectric efficiency even with a thin photoactive layer thickness. In addition, the compounds according to the embodiments have a maximum absorption peak in the green light-producing region of 550 to 600 nm in wavelength, and the full width at half maximum at the maximum absorption wavelength is narrow, so that they exhibit excellent green light selectivity.

[0175] That is, compounds according to one aspect have the advantages of being solution processable, having excellent photoelectric efficiency, and selectively absorbing green light, thus not requiring a separate color filter, and are expected to be easy to commercialize.

Claims

1. A compound represented by the following chemical formula 1: [Chemical Formula 1] In the above chemical formula 1, X1 and X2 are each independently -O-, -S- or -Se-; R1, R2 and R5 are each independently (C1-C12)alkyl or (C1-C12)deuteroalkyl, and R1 and R2 can be connected to (C1-C12)alkylene or (C1-C12)deuteroalkylene to form a fused ring; R3 and R4 are each independently hydrogen, deuterium, (C1-C7)alkyl or (C1-C7)deuteroalkyl, or may be connected to an adjacent substituent to form a ring; a and b are each independently an integer from 1 to 4.

2. In paragraph 1, The compound is a compound represented by the following chemical formula 2 or 3: [Chemical Formula 2] [Chemical Formula 3] In the above chemical formulas 2 and 3, R1, R2 and R5 are each independently (C1-C7)alkyl or (C1-C7)deuteroalkyl, and R1 and R2 can be connected to (C1-C7)alkylene or (C1-C7)deuteroalkylene to form a fused ring; R3, R 4, R6 and R7 are each independently hydrogen, deuterium, (C1-C5)alkyl or (C1-C5)deuteroalkyl; a to d are each independently integers from 1 to 4.

3. In paragraph 2, The compound is represented by the following chemical formula 4: [Chemical Formula 4] In the above chemical formula 4, R1, R2 and R5 are each independently (C1-C7)alkyl or (C1-C7)deuteroalkyl, and R1 and R2 can be connected to (C1-C7)alkylene or (C1-C7)deuteroalkylene to form a fused ring; R3 and R4 are each independently hydrogen, deuterium, (C1-C5)alkyl or (C1-C5)deuteroalkyl.

4. In paragraph 3, A compound wherein the above R1 to R5 are each independently CH3, CD3, CDH2 or CD2H.

5. In paragraph 3, The compound is a compound represented by the following chemical formula 6 or 7: [Chemical Formula 6] [Chemical Formula 7] .

6. In paragraph 1, The compound is selected from the following structures: .

7. In paragraph 1, The above compound is a compound that absorbs light in the green wavelength range.

8. In paragraph 7, A compound having a maximum absorption wavelength in the range of 450 to 650 nm.

9. An organic semiconductor comprising the compound of paragraph 1.

10. In paragraph 9, The above compound is an organic semiconductor used as an electron acceptor.

11. A photoelectric conversion device comprising the organic semiconductor of clause 10.

12. In paragraph 11, A photoelectric conversion element comprising: a first electrode; a second electrode positioned opposite the first electrode; and a photoactive layer positioned between the first electrode and the second electrode and including the organic semiconductor.

13. In paragraph 12, The photoelectric conversion element is an organic photodiode, an organic solar cell, an organic photodetector, an organic photosensor or an organic light-emitting diode.

14. In paragraph 13, The above photoelectric conversion element is a green photodiode, a photoelectric conversion element.

15. An image sensor comprising the photoelectric conversion element of clause 14.

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