Organic semiconductor compound, organic semiconductor layer comprising same and optoelectronic synaptic device capable of discriminating three primary colors comprising same

Abstract

The present invention relates to: an organic semiconductor compound having a chalcone derivative structure; an organic semiconductor layer comprising same; and an optoelectronic synaptic device capable of discriminating the three primary colors and comprising same. The organic semiconductor compound according to the present invention has large differences in wavelength-specific absorbance in the visible spectrum and exhibits a high dipole moment upon light absorption. Therefore, the conductance induced in a switching medium according to the intensity of applied light can be modulated, and thus an optoelectronic synaptic device capable of discriminating various colors can be achieved by outputting different output signals for red light (R), green light (G), and blue light (B) input signals. In addition, the organic semiconductor compound can exhibit optical synaptic properties regardless of the type of switching medium of a resistive memory device, and the optoelectronic synaptic device using same is a two-terminal memristor-type device and highly integrated.

Description

Organic semiconductor compound, organic semiconductor layer containing the same, and optical synapse element capable of distinguishing three primary colors containing the same

[0001] The present invention relates to an organic semiconductor compound, an organic semiconductor layer including the same, and an optical synapse element including the same capable of distinguishing three primary colors, and more particularly, to an organic semiconductor compound which, when applied to a synapse element as a chalcone derivative, outputs differential output signals for each of red light (R), green light (G), and blue light (B), an organic semiconductor layer including the same, and an optical synapse element including the same capable of distinguishing three primary colors.

[0002] The human visual system is an essential component of the human body, enabling us to perceive complex visual information from the external world. The retina not only uses photoreceptors to convert visual input into electrical signals that are transmitted to the brain, but also performs preprocessing to extract key features from the large-scale input signal.

[0003] Therefore, to implement an efficient artificial vision system mimicking the retina, an optoelectronic device capable of converting optical signals into electrical signals while possessing synaptic plasticity that contributes to local computation of visual information is required. Furthermore, one of the retina's key functions is its ability to perceive diverse information, and implementing an artificial vision system requires multispectral color discrimination.

[0004] An optical synapse device is a device developed to mimic the human visual system, and is a device having synaptic plasticity characteristics that exhibit conductance changes in response to light stimulation. In this regard, Korean Patent Publication No. 10-2023-0095532 discloses an optical synapse device based on a HfO2 / IGZO oxide bilayer, which includes: a substrate; a dielectric layer positioned on the substrate; an IGZO channel layer positioned on the dielectric layer and including IGZO (In-Ga-Zn-O) oxide; source / drain electrodes positioned on the channel layer; and a HfO2 thin film layer positioned on the source / drain electrodes.

[0005] As another example, Korean Patent Publication No. 10-2023-0069026 discloses an optical synapse transistor including a gate electrode portion; a dielectric portion provided on the gate electrode portion; an electron trap portion provided on the dielectric portion; an opto-electrical conversion portion provided on the electron trap portion; a channel portion provided on the opto-electrical conversion portion; a source electrode portion electrically connected to the channel portion; and a drain electrode portion provided to be spaced apart from the source electrode portion and electrically connected to the channel portion.

[0006] However, most conventional optical synapse devices are 3-terminal based field effect transistor devices, which have limitations in that they are difficult to achieve high integration and that it is difficult to distinguish and recognize red light (R), green light (G), and blue light (B) in the visible light range.

[0007] Accordingly, there is a demand for the development of an optical synapse device that can achieve high integration by implementing optical synapse characteristics in a two-terminal memristor structure and outputs differential output signals for each input signal of red light (R), green light (G), and blue light (B), thereby enabling the distinction of various colors.

[0008] One object of the present invention is to provide an organic semiconductor compound having a large difference in absorption by wavelength within the visible light wavelength range and exhibiting a high dipole moment when absorbing light.

[0009] Another object of the present invention is to provide an organic semiconductor layer comprising the organic semiconductor compound.

[0010] Another object of the present invention is to provide an optical synapse device capable of implementing optical synapse characteristics in a two-terminal memristor structure including the organic semiconductor layer and outputting differential output signals for each of red light (R), green light (G), and blue light (B) input signals.

[0011] To achieve the above object, the present invention provides a chalcone derivative having a structure represented by the following chemical formula 1 as an organic semiconductor compound:

[0012] [Chemical Formula 1]

[0013]

[0014] In the above chemical formula 1,

[0015] R0 is -H or is connected to R6 to form a benzene ring,

[0016] R1 and R2 are each independently a proton-donating substituent selected from the group consisting of -H; or -OH, -NH2, -NHR and -NRR',

[0017] R3 is or and,

[0018] R4 and R5 are, each independently, -H, an alkyl group having 1 to 6 carbon atoms, -OC(=O)-R, -OR, -C=O-NRR', -NHR or -NRR',

[0019] If R0 is -H, R6 is -H, -F, -Cl, -Br, -I, -CF3, -C=OR, -SO3R, -CN, -NO2, or -NR3 +and,

[0020] R and R' are each independently an alkyl group having 1 to 6 carbon atoms.

[0021] Preferably, in the above chemical formula 1, at least one of R1 and R2 may be a proton-donating substituent.

[0022] Preferably, in the above chemical formula 1, R0 is -H or is connected to R6 to form a benzene ring, R1 and R2 are each independently -H or -OH, and at least one of R1 and R2 is -OH,

[0023] R3 is or and,

[0024] R4 and R5 are each independently -H or an alkyl group having 1 to 6 carbon atoms, and when R0 is -H, R6 may be -H.

[0025] In the present invention, the organic semiconductor compound of the above chemical formula 1 may have a structure of the following chemical formula 2 or chemical formula 3:

[0026] [Chemical Formula 2]

[0027]

[0028] [Chemical Formula 3]

[0029]

[0030]

[0031] The present invention also provides an organic semiconductor layer comprising the organic semiconductor compound.

[0032]

[0033] The present invention also provides an optical synapse device including the organic semiconductor layer.

[0034] The optical synapse element of the present invention is an optical synapse element including a lower electrode; a switching medium formed on the lower electrode and having a resistance that changes by a voltage or an electric field; and an upper electrode formed on the switching medium, and may include the organic semiconductor layer laminated on or under the switching medium.

[0035] In the present invention, the switching medium is nickel oxide (NiO x ), aluminum oxide (Al2O3), iron oxide (FeO x ), copper oxide (CuO x ), tin oxide (SnO2), and polymethyl methacrylate (PMMA).

[0036] In the present invention, the switching medium can be formed by coating the switching material using a solution process and then performing a heat treatment.

[0037] In the present invention, the heat treatment during formation of the switching medium can be performed at 400 to 700°C for 30 minutes to 5 hours.

[0038] In the present invention, the switching medium can be formed by depositing the switching material by sputtering, atomic layer deposition (ALD), pulsed laser deposition (PLD), thermal evaporation, electron-beam evaporation, physical vapor deposition (PVD), molecular beam epitaxy (MBE), or chemical vapor deposition (CVD).

[0039] In the present invention, the organic semiconductor layer can be formed by coating the organic semiconductor compound using a solution process and then performing a heat treatment.

[0040] In the present invention, the heat treatment during formation of the organic semiconductor layer can be performed at 90 to 120°C for 1 to 60 minutes.

[0041] In the present invention, the upper electrode and the lower electrode are each independently Al, Ag, Au, Ti, Ni, Mo, Cu, Pt, Fe or an alloy thereof, TiN, WN, SrTiO3, LaNiO3, ITO (indium tin oxide), IZO (indium zinc oxide), GZO (gallium zinc oxide), IGZO (indium gallium-doped zinc oxide), AZO (aluminum zinc oxide), IGTO (indium gallium-doped tin oxide), FTO (fluorine-doped tin oxide), ZnO, SnO2, TiO2, silver nanowire, carbon nanotube (CNT), single-walled carbon nanotube (SWCNT), double-walled carbon nanotube (DWCNT), multi-walled carbon nanotube (MWCNT), graphene, polyethylenedioxythiophene (PEDOT), and It may include one or more conductive materials selected from the group consisting of PEDOT:PSS (poly(3,4-ethylenedioxythiophene):polystyrenesulfonate).

[0042] In the present invention, the upper electrode may include an electrically conductive material having a lower work function than the lower electrode.

[0043] In the present invention, the upper electrode and the lower electrode can be formed independently by sputtering, atomic layer deposition (ALD), pulsed laser deposition (PLD), thermal evaporation, electron-beam evaporation, physical vapor deposition (PVD), molecular beam epitaxy (MBE), chemical vapor deposition (CVD), or solution process.

[0044] The optical synaptic element of the present invention can output differential output signals for each of the input signals of red light (R), green light (G), and blue light (B).

[0045] The organic semiconductor compound of the present invention exhibits a large difference in absorption by wavelength within the visible light wavelength range and a high dipole moment when absorbing light. Therefore, the conductance inside the switching medium induced according to the applied light intensity can be controlled, so that differentiated output signals can be output for red light (R), green light (G), and blue light (B) input signals, thereby enabling the implementation of an optical synapse element capable of distinguishing various colors. In addition, the organic semiconductor compound can exhibit optical synapse characteristics regardless of the type of switching medium of the resistance memory element, and an optical synapse element using the same has excellent integration as a two-terminal memristor-type element.

[0046] FIG. 1 is a drawing illustrating ESIPT characteristics by mutual conversion of enol and keto forms of an organic semiconductor compound according to one embodiment of the present invention.

[0047] FIG. 2 is a schematic diagram showing the structure of an optical synapse element according to one embodiment of the present invention.

[0048] FIGS. 3a and 3b are drawings each explaining the operating principle (a) and energy band diagram (b) of an optical synapse device according to one embodiment of the present invention.

[0049] Figure 4 shows the results of measuring the absorbance of an organic semiconductor layer according to one embodiment of the present invention.

[0050] FIGS. 5a to 5d are graphs showing the transport characteristics of an OFET using an organic semiconductor compound (CH-M, CM, CH-P, and CP) according to one embodiment of the present invention, respectively.

[0051] Figures 6a to 6c are graphs showing output characteristics confirmed through a single pulse input (a), 50 pulse input (b), and 1 to 20 mW RGB pulse input (c) of an optical synapse element according to one embodiment of the present invention, respectively.

[0052] Figures 7a to 7c each show graphs showing the EPSC characteristics according to the optical pulse amplitude (a), pulse width (b), and pulse interval (c) of an optical synapse element to which CH-M is applied according to one embodiment of the present invention.

[0053] Figures 8a to 8c each show graphs showing the EPSC characteristics according to the optical pulse amplitude (a), pulse width (b), and pulse interval (c) of an optical synapse element to which CH-P is applied according to one embodiment of the present invention.

[0054] Unless otherwise defined, 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. In general, the nomenclature used herein is well known and commonly used in the art.

[0055] In this specification, when a component such as a substrate or layer is said to be "on" another component, this may include not only cases where it is directly on top of the other component, but also cases where there is another component in between.

[0056]

[0057] The present invention relates to an organic semiconductor compound capable of distinguishing various colors by outputting differential output signals for each of red light (R), green light (G), and blue light (B) input signals, an organic semiconductor layer including the compound, and an optical synapse element including the compound.

[0058] The organic semiconductor compound of the present invention exhibits a large difference in absorption by wavelength within the visible light wavelength range and a high dipole moment upon light absorption. Therefore, the conductance inside the switching medium induced according to the applied light intensity can be controlled, thereby outputting differentiated output signals for each input signal of red light (R), green light (G), and blue light (B), thereby enabling implementation of an optical synapse element capable of distinguishing various colors. In addition, the organic semiconductor compound can exhibit optical synapse characteristics regardless of the type of switching medium of the resistance memory element.

[0059] The organic semiconductor compound of the present invention is a chalcone derivative and can be represented by the following chemical formula 1:

[0060] [Chemical Formula 1]

[0061]

[0062] In the above chemical formula 1,

[0063] R0 is hydrogen (-H) or is connected to R6 to form a benzene ring,

[0064] R1 and R2 may each independently be a proton-donating substituent selected from the group consisting of hydrogen (-H); or a hydroxyl group (-OH), an amino group (-NH2), and an amine group (-NHR or -NRR'),

[0065] R3 is or and,

[0066] R4 and R5 are each independently hydrogen (-H), an alkyl group having 1 to 6 carbon atoms, an ester group (-OC(=O)-R), an alkoxy group (-OR), an amide group (-C=O-NRR'), or an amine group (-NHR or -NRR'),

[0067] When R0 is hydrogen (-H), R6 is hydrogen (-H), a halogen group (-F, -Cl, -Br or -I), a fluoroalkyl group (-CF3), a carbonyl group (-C=OR), a sulfonyl group (-SO3R), -CN, -NO2 or -NR3 + and,

[0068] R and R' are each independently an alkyl group having 1 to 6 carbon atoms.

[0069] The organic semiconductor compound of the present invention is sensitive to visible light, and can improve photoreactivity by introducing an electron donor (R3 to R5) and a naphthalene structure formed by forming a benzene ring of R0 and R6 or an electron withdrawing group (R6).

[0070] Preferably, in the above chemical formula 1, at least one of R1 and R2 may be a proton-donating substituent selected from the group consisting of a hydroxyl group (-OH), an amino group (-NH2), and an amine group (-NHR or -NRR'). When a proton-donating substituent is introduced into a chalcone derivative in this way, a strong dipole moment in an excited state can be formed, and the visible light absorbance can be increased and the difference in absorbance between wavelengths can be increased, thereby improving color discrimination ability.

[0071] Preferably, in the above chemical formula 1, R0 is hydrogen (-H) or is connected to R6 to form a benzene ring,

[0072] R1 and R2 can each independently be hydrogen (-H) or a hydroxyl group (-OH), and at least one of R1 and R2 is a hydroxyl group,

[0073] R3 is or and,

[0074] R4 and R5 are each independently hydrogen (-H) or an alkyl group having 1 to 6 carbon atoms,

[0075] If R0 is hydrogen (-H), R6 can be hydrogen (-H).

[0076] In a preferred embodiment of the present invention, the organic semiconductor compound may be a compound represented by the following chemical formula 2. The nomenclature of the compound represented by the following chemical formula 2 is (E)-3-(4-(dimethylamino)phenyl)-1-(1-hydroxynaphthalen-2-yl)prop-2-en-1-one, which may be abbreviated as "CH-M" in describing the present invention.

[0077] [Chemical Formula 2]

[0078]

[0079] In a preferred embodiment of the present invention, the organic semiconductor compound may be a compound represented by the following chemical formula 3. The nomenclature of the compound represented by the following chemical formula 3 is (E)-3-(4-(diphenylamino)phenyl)-1-(1-hydroxynaphthalen-2-yl)prop-2-en-1-one, which may be abbreviated as "CH-P" in describing the present invention.

[0080] [Chemical Formula 3]

[0081]

[0082] In the case of the above CH-P, the dimethyl group in CH-M is replaced with a diphenyl group, thereby reducing the optical band gap and increasing the difference in absorption between wavelengths, thereby enabling visible light sensitivity and improving color reactivity. In this regard, in the embodiment of the present invention, it was confirmed that the optical synaptic characteristics and color discrimination ability of the device were superior when CH-P was used compared to CH-M.

[0083] The organic semiconductor compound of the present invention exhibits excited-state intramolecular proton transfer (ESIPT) characteristics, which are phototautomerization characteristics in which protons move within an excited molecule. This maximizes the energy difference between absorption and emission, thereby minimizing fluorescence reduction and providing advantageous properties for implementing stimulated luminescence.

[0084] Specifically, referring to FIG. 1, the organic semiconductor compound of the present invention has a tautomeric molecular structure capable of changing between a stable enol form in the ground state and a stable keto form in the excited state through proton transfer. This interconversion between the enol form and the keto form involves the movement of hydrogen atoms and the subsequent rearrangement of bonding electrons.

[0085] In the molecular structure of the above organic semiconductor compound, the keto form may include a carbonyl group (-C=O), and the enol form may include a hydroxyl group (C=C-OH) bonded to one of the double-bonded carbon atoms.

[0086] The organic semiconductor compound used in the present invention has ESIPT characteristics, has no self-absorption, and can have long-wavelength fluorescence, so it can be applied to various purposes such as an organic light-emitting device (OLED), a fluorescent sensor, a chemosensor, a gain media for an organic laser, and a hole transport material.

[0087] In particular, when an optical synapse device is manufactured by forming a semiconductor layer using the organic semiconductor compound of the present invention and positioning the semiconductor layer on a switching medium, multiple wavelengths in the visible light region can be easily detected and identified. In the present invention, the optical synapse device can be implemented as a highly integrated two-terminal memristor type device, and in this case, it is possible to distinguish various colors by outputting differentiated output signals for each input signal of red light (R), green light (G), and blue light (B).

[0088]

[0089] Accordingly, the present invention also provides an organic semiconductor layer including the organic semiconductor compound and an optical synapse element including the same.

[0090] The most crucial element that manifests the optical synaptic properties of a device is an organic semiconductor layer, and the optical synaptic device of the present invention includes an organic semiconductor layer formed of the organic semiconductor compound. The organic semiconductor layer absorbs light, inducing a high dipole moment when the molecule is in an excited state (an excited state), and can delay the time in the excited state due to the ESIPT characteristic.

[0091] The optical synapse element of the present invention is implemented with a highly integrated two-terminal memristor-type structure, and can be integrated into a three-dimensional (3D) crossbar array structure, and can detect multiple colors without a color filter and peripheral circuits, so that it can be applied to a high-sensitivity image sensor.

[0092] The optical synapse element of the present invention is an optical synapse element including a lower electrode; a switching medium formed on the lower electrode and having a resistance that changes by a voltage or an electric field; and an upper electrode formed on the switching medium, and may include an organic semiconductor layer laminated on or under the switching medium.

[0093] Specifically, in one embodiment of the present invention, the optical synapse element may include a lower electrode, a switching medium formed on the lower electrode, an organic semiconductor layer formed on the switching medium, and an upper electrode formed on the organic semiconductor layer, and in another embodiment, the optical synapse element may include a lower electrode, an organic semiconductor layer formed on the lower electrode, a switching medium formed on the organic semiconductor layer, and an upper electrode formed on the switching medium.

[0094] FIG. 2 illustrates the structure of an optical synapse element according to one embodiment of the present invention, wherein the optical synapse element may include a lower electrode (10); a switching medium (20) formed on the lower electrode; an organic semiconductor layer (30) formed on the switching medium; and an upper electrode (40) formed on the organic semiconductor layer.

[0095] The optical synaptic device of the present invention may include a substrate that can serve as a support for the device under the lower electrode. For example, the substrate may be at least one substrate selected from the group consisting of glass, polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polystyrene (PS), polycarbonate (PC), polyimide (PI), polyvinyl chloride (PVC), polyvinylpyrrolidone (PVP), polyethylene (PE), stainless steel, wool, silicon (Si), and SiO2.

[0096] The lower electrode is selected from the group consisting of Al, Ag, Au, Ti, Ni, Mo, Cu, Pt, Fe or alloys thereof, TiN, WN, SrTiO3, LaNiO3, ITO (indium tin oxide), IZO (indium zinc oxide), GZO (gallium zinc oxide), IGZO (indium gallium-doped zinc oxide), AZO (aluminum zinc oxide), IGTO (indium gallium-doped tin oxide), FTO (fluorine-doped tin oxide), ZnO, SnO2, TiO2, silver nanowire, carbon nanotube (CNT, carbon nanotube), SWCNT (single-walled carbon nanotube), DWCNT (double-walled carbon nanotube), MWCNT (multi-walled carbon nanotube), graphene, PEDOT (polyethylenedioxythiophene) and PEDOT:PSS (poly(3,4-ethylenedioxythiophene):polystyrenesulfonate). It may contain one or more challenging substances.

[0097] The above switching medium (resistance change layer) exhibits the characteristic of changing resistance by voltage or electric field, and is nickel oxide (NiO x ), aluminum oxide (Al2O3), iron oxide (FeO x ), copper oxide (CuO x ), tin oxide (SnO2), and polymethyl methacrylate (PMMA).

[0098] The above switching medium can be formed by coating a switching material using a solution process and then heat treating it, and the coating process can be performed using a coating technique such as spin coating, spray coating, bar coating, dip coating, curtain coating, slot coating, roll coating, or gravure coating. The heat treatment after coating can be performed at 400 to 700°C for 30 minutes to 5 hours.

[0099] Additionally, the switching medium may be formed by depositing a switching material by sputtering, atomic layer deposition (ALD), pulsed laser deposition (PLD), thermal evaporation, electron-beam evaporation, physical vapor deposition (PVD), molecular beam epitaxy (MBE), or chemical vapor deposition (CVD).

[0100] The organic semiconductor layer in contact with the above switching medium has a high induced dipole moment in an excited state due to light absorption, and exhibits tautomerism (excited-state intramolecular proton transfer, ESIPT) characteristics that can change between a stable enol form (C=C-OH) in the ground state and a stable keto form (-C=O) in the excited state through proton transfer for excited state delay, and may include the organic semiconductor compound of the present invention described above.

[0101] Figures 3a and 3b respectively illustrate the operating principle (a) and the energy band diagram (b) of the optical synapse device according to the present invention. In a device in which an organic semiconductor material is laminated, a built-in potential is generated due to the difference in work functions between the lower electrode and the upper electrode, which causes an induced dipole moment. When light is applied to the optical synapse device, the organic semiconductor layer has a high dipole moment, which further increases the built-in potential, resulting in an effect equivalent to applying an external electric field to a device in a stable state. This increases the conductance within the switching medium, thereby exhibiting optical synapse characteristics.

[0102] That is, the optical synapse element of the present invention can exhibit optical synapse characteristics by enhancing the dipole moment of the organic semiconductor layer according to the application of light, thereby increasing the conductance of the switching medium. Such characteristics of the present invention can be applied regardless of the type of switching medium, thereby providing a wide range of material selectivity when developing an image sensor module to which the optical synapse element is applied.

[0103] The above organic semiconductor layer can be formed by coating an organic semiconductor compound using a solution process and then heat treating, and the coating process can be performed using a coating technique such as spin coating, spray coating, bar coating, dip coating, curtain coating, slot coating, roll coating, or gravure coating. The heat treatment after coating can be performed at 90 to 120°C for 1 to 60 minutes.

[0104] The upper electrode may be the same as or different from the lower electrode, and is preferably formed of an electrically conductive material having a lower work function than the lower electrode. Examples of the conductive material forming the upper electrode are the same as those described in the description of the lower electrode, so they are omitted.

[0105] The lower electrode and the upper electrode can be formed independently by any one of sputtering, atomic layer deposition (ALD), pulsed laser deposition (PLD), thermal evaporation, electron-beam evaporation, physical vapor deposition (PVD), molecular beam epitaxy (MBE), chemical vapor deposition (CVD), and solution process.

[0106] The shapes of the upper and lower electrodes can be appropriately modified and manufactured according to the structure of the device. For example, the lower electrode may be formed in the form of a substrate, and the upper electrode may be formed in the form of a pattern including a plurality of electrode units spaced apart from each other. Alternatively, the lower and upper electrodes may be formed in the form of a cross-bar array in which they intersect in a cross (+) shape.

[0107] In the present invention, by introducing an organic semiconductor compound with a high difference in absorbance by wavelength to generate a differentiated output signal for an optical input signal by wavelength, an effect capable of recognizing and identifying multiple colors in the visible light range can be realized. Accordingly, visible light identification is possible with a single device itself, without a color filter or peripheral circuit configuration. In addition, since the optical synapse device of the present invention is a 2-terminal-based memristor-type device that can be 3D-stacked, the circuit integration can be increased compared to a 3-terminal transistor-type optical synapse device.

[0108] The optical synapse element of the present invention can be applied to a device to which a machine vision system is applied, and due to the characteristics of the optical synapse element, it can receive data from external visual information and perform data preprocessing before transmitting the data to a processing and storage device, so that when applied to an image sensor module, it can efficiently process a large amount of image data.

[0109] Therefore, the optical synapse device of the present invention can be applied to various fields such as MRI and CT scan technology in the medical field requiring real-time visual information recognition and analysis, autonomous driving system technology in the automotive industry, and drone and aerial photography (terrain mapping, object detection technology) in the military field.

[0110]

[0111] Example

[0112]

[0113] The present invention is described in more detail through the following examples. However, these examples are provided to illustrate some experimental methods and compositions for the purpose of illustratively explaining the present invention, and the scope of the present invention is not limited to these examples.

[0114]

[0115] Synthesis Example 1: Synthesis of organic semiconductor compound CH-M

[0116]

[0117] (E)-3-(4-(dimethylamino)phenyl)-1-(1-hydroxynaphthalen-2-yl)prop-2-en-1-one (CH-M) was synthesized as a chalcone-based organic semiconductor compound.

[0118] 1.5 g (8.06 mmol) of 2-acetyl-1-naphthol and 1.2 g (8.06 mmol) of (dimethylamino)benzaldehyde were placed in a 100 mL round-bottom flask and dissolved in 30 mL of ethanol. 0.662 mL of pyrrolidine was then added to the solution in the round-bottom flask and stirred overnight at room temperature. Upon addition of pyrrolidine, the color of the solution changed from yellow to red, indicating completion of the reaction. The mixture was filtered and washed with cold ethanol.

[0119] After drying the filtrate using MgSO4, column purification was performed using silica gel column chromatography using ethyl acetate (EA) and n-hexane in a weight ratio of 25:75. The purified powder was approximately 1.93 g, and the yield was confirmed to be approximately 64.5%.

[0120]

[0121] Synthesis Example 2: Synthesis of organic semiconductor compound CH-P

[0122]

[0123] (E)-3-(4-(diphenylamino)phenyl)-1-(1-hydroxynaphthalen-2-yl)prop-2-en-1-one (CH-P) was synthesized to improve color recognition ability by improving the donor-acceptor (DA) ability of the molecule through substitution of the electron donating group by replacing the dimethyl group of CH-M.

[0124] 1.5 g (8.06 mmol) of 2-acetyl-1-naphthol and 2.2 g (8.06 mmol) of (diphenylamino)benzaldehyde were placed in a 100 mL round-bottom flask and dissolved in 30 mL of ethanol. 0.662 mL of pyrrolidone was then added to the solution in the round-bottom flask and stirred overnight at room temperature. Upon addition of pyrrolidine, the reaction was completed when the color of the solution changed from yellow to red, and the mixture was filtered and washed with cold ethanol.

[0125] After drying the filtrate using MgSO4, column purification was performed using silica gel column chromatography using ethyl acetate (EA) and n-hexane in a weight ratio of 20:80. The purified powder was approximately 1.34 g, and the yield was confirmed to be approximately 37.7%.

[0126]

[0127] Manufacturing Example 1: Fabrication of an optical synapse device

[0128]

[0129] An optical synapse device having a two-terminal memristor-type structure was fabricated using the organic semiconductor compound of the present invention.

[0130] First, fluorine-doped tin oxide (FTO) was coated as a lower electrode on a glass substrate. Nickel oxide (NiO) as a switching medium was coated on the lower electrode. x) was coated through a solution spin process (2,000 rpm, 30 s). Water was used as the solvent for the nickel oxide solution, and the concentration was adjusted to 50 mg / mL.

[0131] The substrate coated with a nickel oxide thin film was heated to 550°C for 10 minutes in an oven-type furnace, then heat treated at 550°C for 2 hours and then taken out.

[0132] Thereafter, the organic semiconductor compound of Synthesis Example 1 or 2 was ionized on a magnetic stirrer for 30 minutes using chlorobenzene (CB) as a solvent. The ionized organic semiconductor compound was spin-coated (2,000 rpm, 30 s) on a nickel oxide-coated substrate, and then heat-treated on a hot plate at 100°C for 10 minutes. Thereafter, silver (Ag) was deposited as an upper electrode using a thermal evaporator to fabricate an optical synapse device.

[0133]

[0134] Experimental Example 1: Analysis of Device Characteristics According to Organic Semiconductor Compounds

[0135]

[0136] The absorbance of organic semiconductor thin films formed by casting the CH-M and CH-P compounds of Synthetic Examples 1 and 2 onto quartz glass was measured. For comparison, the same experiment was performed for (E)-3-(4-(dimethylamino)phenyl)-1-(naphthalen-2-yl)prop-2-en-1-one (CM) and (E)-3-(4-(diphenylamino)phenyl)-1-(naphthalen-2-yl)prop-2-en-1-one (CP) compounds in which the hydroxyl group was excluded from CH-M and CH-P.

[0137] Figure 4 shows the results of the absorbance measurement, and CH-M and CH-P had higher absorbance in the visible light range than CM and CP, respectively. In particular, CH-P had higher absorbance at 450 nm and a large difference in absorbance between wavelengths of 450 and 650 nm.

[0138] Accordingly, it was found that a device with excellent optical synaptic properties and color discrimination ability can be manufactured by using the organic semiconductor compound of the present invention, particularly CH-P.

[0139]

[0140] Experimental Example 2: Analysis of the dipole moment induced in an organic semiconductor layer

[0141]

[0142] An organic field-effect transistor (OFET) with a SiO2 / dielectric layer / Al2O3 structure was fabricated using the organic semiconductor compounds of Synthesis Examples 1 and 2 as the gate dielectric layer, and the generation of a dipole moment induced in the organic semiconductor layer under electric field and light irradiation was confirmed using this. For comparison, the same experiments as in Experimental Example 1 were also performed for CM and CP.

[0143] Figures 5a to 5d show V for cases where CH-M, CM, CH-P and CP are applied, respectively. DS Transport characteristics of OFET under -15 V conditions (I DS vs. V GS ) is shown, and V of OFET having CH-M and CH-P having absorbance in the visible light region T The figures are for visible light irradiation (blue light, 450 nm, 5 mW / cm 2 ) was significantly reduced, but no significant change was observed under the same conditions when CM and CP were used.

[0144] Accordingly, it was confirmed that when the organic semiconductor compound according to the present invention is applied, a strong dipole moment in the excited state is formed.

[0145]

[0146] Experimental Example 3: Analysis of the electrical output characteristics of an optical synapse device according to visible light input.

[0147]

[0148] In order to confirm the electrical output characteristics of the organic semiconductor compound of the present invention, an optical synapse element using CH-P was manufactured using the method of Manufacturing Example 1, and the electrical output characteristics for visible light (RGB) input were confirmed.

[0149] Fig. 6a shows the output characteristics of the optical synapse element for each single pulse input of red light (R), green light (G), and blue light (B), and Fig. 6b shows the output characteristics confirmed through 50 pulse inputs of each of RGB. In addition, Fig. 6c shows the output characteristics confirmed through RGB pulse inputs of 1 to 20 mW.

[0150] The above output measurement results showed a difference of approximately 100 times between RGB wavelength signals, and accordingly, it was confirmed that the optical synapse element using CH-P had a clear signal discrimination characteristic between RGB.

[0151]

[0152] Experimental Example 4: Analysis of EPSC Characteristics of Optical Synapse Devices

[0153]

[0154] Figures 7a to 7c and 8a to 8c show the excitatory postsynaptic current (EPSC) response characteristics of a memristor to which CH-M (Figures 7a to 7c) and CH-P (Figures 8a to 8c) are applied, respectively.

[0155] Figures 7a and 8a show the results of analyzing the characteristics according to the amplitude of the light pulse for a blue light pulse (450 nm, width 1 s), and Figures 7b and 8b show the results for a blue light pulse (450 nm, 5 mW / cm 2 ) is the result of analyzing the characteristics according to the pulse width. In addition, Figs. 7c and 8c show the paired-pulse facilitation (PPF) index (Read voltage 0.05 V) according to the interval (△t) between two consecutive pulses.

[0156] Experimental results confirmed that the memristor using the organic semiconductor compounds CH-M and CH-P of the present invention can efficiently respond to blue light (450 nm) and exhibit EPSC and PPF behavior. The PPF behavior of the memristor signifies short-term synaptic memory, and as a non-volatile memory, it is accompanied by an increase in conductance even after a pulse.

[0157] According to these non-volatile characteristics, it was confirmed that a memristor using the organic semiconductor compound of the present invention can exhibit long-term plasticity that converts short-term memory into long-term memory.

[0158]

[0159] While specific aspects of the present invention have been described in detail above, it will be apparent to those skilled in the art that these specific descriptions merely represent preferred embodiments and do not limit the scope of the present invention. Therefore, the substantial scope of the present invention is defined by the appended claims and their equivalents.

[0160]

[0161] [Explanation of symbols]

[0162] 10: Lower electrode

[0163] 20: Switching Medium

[0164] 30: Organic semiconductor layer

[0165] 40: Upper electrode

Claims

1. An organic semiconductor compound having a structure represented by the following chemical formula 1: [Chemical Formula 1] In the above chemical formula 1, R0 is -H or is connected to R6 to form a benzene ring, R1 and R2 are each independently a proton-donating substituent selected from the group consisting of -H; or -OH, -NH2, -NHR and -NRR', R3 is or and, R4 and R5 are, each independently, -H, an alkyl group having 1 to 6 carbon atoms, -OC(=O)-R, -OR, -C=O-NRR', -NHR or -NRR', If R0 is -H, R6 is -H, -F, -Cl, -Br, -I, -CF3, -C=OR, -SO3R, -CN, -NO2, or -NR3 + and, R and R' are each independently an alkyl group having 1 to 6 carbon atoms.

2. In paragraph 1, In the above chemical formula 1, An organic semiconductor compound, wherein at least one of R1 and R2 is a proton-donating substituent.

3. In paragraph 1, In the above chemical formula 1, R0 is -H or is connected to R6 to form a benzene ring, R1 and R2 are each independently -H or -OH, and at least one of R1 and R2 is -OH, R3 is or and, R4 and R5 are each independently -H or an alkyl group having 1 to 6 carbon atoms, An organic semiconductor compound in which R0 is -H and R6 is -H.

4. In paragraph 1, An organic semiconductor compound having the structure of the above chemical formula 1, wherein the organic semiconductor compound has the structure of the following chemical formula 2 or chemical formula 3: [Chemical Formula 2] [Chemical Formula 3] .

5. An organic semiconductor layer comprising an organic semiconductor compound according to any one of claims 1 to 4.

6. An optical synaptic element comprising a lower electrode; a switching medium formed on the lower electrode and having a resistance that changes by a voltage or an electric field; and an upper electrode formed on the switching medium, An optical synapse device comprising an organic semiconductor layer of claim 5 laminated on the upper or lower portion of the switching medium.

7. In paragraph 6, The above switching medium is nickel oxide (NiO x ), aluminum oxide (Al2O3), iron oxide (FeO x ), copper oxide (CuO x ), tin oxide (SnO2), and polymethyl methacrylate (PMMA), comprising at least one switching material selected from the group consisting of:

8. In paragraph 7, An optical synapse element, wherein the switching medium is formed by coating the switching material using a solution process and then heat-treating it.

9. In paragraph 8, An optical synapse device, wherein the above heat treatment is performed at 400 to 700°C for 30 minutes to 5 hours.

10. In paragraph 7, An optical synapse device in which the switching medium is formed by depositing the switching material by sputtering, atomic layer deposition (ALD), pulsed laser deposition (PLD), thermal evaporation, electron-beam evaporation, physical vapor deposition (PVD), molecular beam epitaxy (MBE), or chemical vapor deposition (CVD).

11. In paragraph 6, An optical synapse element, wherein the organic semiconductor layer is formed by coating the organic semiconductor compound using a solution process and then heat-treating it.

12. In paragraph 11, An optical synaptic device, wherein the above heat treatment is performed at 90 to 120°C for 1 to 60 minutes.

13. In paragraph 6, The upper electrode and the lower electrode are each independently Al, Ag, Au, Ti, Ni, Mo, Cu, Pt, Fe or an alloy thereof, TiN, WN, SrTiO3, LaNiO3, ITO (indium tin oxide), IZO (indium zinc oxide), GZO (gallium zinc oxide), IGZO (indium gallium-doped zinc oxide), AZO (aluminum zinc oxide), IGTO (indium gallium-doped tin oxide), FTO (fluorine-doped tin oxide), ZnO, SnO2, TiO2, silver nanowire, carbon nanotube (CNT), single-walled carbon nanotube (SWCNT), double-walled carbon nanotube (DWCNT), multi-walled carbon nanotube (MWCNT), graphene, polyethylenedioxythiophene (PEDOT), and An optical synaptic device comprising at least one conductive material selected from the group consisting of PEDOT:PSS (poly(3,4-ethylenedioxythiophene):polystyrenesulfonate).

14. In paragraph 6, An optical synaptic device, wherein the upper electrode comprises an electrically conductive material having a lower work function than the lower electrode.

15. In paragraph 6, An optical synapse device in which the upper electrode and the lower electrode are each independently formed by sputtering, atomic layer deposition (ALD), pulsed laser deposition (PLD), thermal evaporation, electron-beam evaporation, physical vapor deposition (PVD), molecular beam epitaxy (MBE), chemical vapor deposition (CVD), or solution process.

16. In paragraph 6, An optical synapse element, wherein the optical synapse element outputs a differential output signal for each of the input signals of red light (R), green light (G), and blue light (B).

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