Perovskite light receiving element and its manufacturing method

Abstract

The present disclosure relates to a method for manufacturing a perovskite photodetector and a perovskite photodetector manufactured therefrom, comprising the steps of: forming an electron transport layer by depositing an organic tin precursor on a first electrode by atomic layer deposition; forming a photoactive layer by applying a perovskite precursor solution on the electron transport layer; forming a hole blocking layer on the photoactive layer; and forming a hole transport layer on the hole blocking layer.

Description

Technology Field

[0001] The present disclosure relates to a perovskite photodetector and a method for manufacturing the same. Background Technology

[0002] A photodetector refers to a device that converts light energy into electrical energy, and it is widely used in fields such as cameras, camcorders, optical sensors, and solar cells.

[0003] Although photodiodes (PDs) based on semiconductor compounds containing Group 3 to 5 elements, such as silicon (Si) and gallium nitride (GaN), have been commercialized as conventional light-receiving devices, vertical-structured light-receiving devices based on the aforementioned materials require complex and high-cost processes such as MOCVD (metal-organic chemical vapor deposition) and MBE (molecular-beam epitaxy). Furthermore, to clearly realize RGB colors, the thickness of the light-receiving device must be fabricated to the micrometer level; however, as the device thickness increases, a problem arises where parasitic absorption occurs, in which the light absorption rates of the red, green, and blue regions overlap. In particular, due to low external quantum efficiency (EQE) and low charge capture rate in the blue absorption region, there is a need to develop new materials capable of solving resolution and color reproduction issues.

[0004] Perovskite compound-based photodetectors have been developed as a means to replace conventional photodetectors. Perovskite-based photodetectors are gaining attention for applications such as photovoltaics, light-emitting diodes, and photodetectors due to their spectral tunability, excellent photoelectric properties, and easy solution-based manufacturing processes.

[0005] However, there is a problem in which leakage current occurs due to interfacial defects at the interface between the perovskite compound and the adjacent electron transport and hole transport layers, thereby degrading the performance and lifespan of the photodetector. In particular, there is an urgent need for research on fabrication methods for perovskite compound-based photodetectors to enhance electron extraction and transport capabilities by improving the film quality of the electron transport layer, which plays a crucial role in improving the performance of the photodetector. The problem to be solved

[0006] The purpose of the present disclosure is to solve the problems of the prior art described above by providing a perovskite photodetector comprising an electron transport layer with high crystallinity and minimized surface defects, and a method for manufacturing the same.

[0007] Another object of the present disclosure is to provide a perovskite photodetector capable of improving response speed and suppressing dark current, and a method for manufacturing the same. means of solving the problem

[0008] The present invention provides a method for manufacturing a perovskite photodetector, wherein the method for manufacturing the perovskite photodetector comprises the steps of: forming an electron transport layer by depositing an organic tin precursor on a first electrode by atomic layer deposition; forming a photoactive layer by applying a perovskite precursor solution on the electron transport layer; forming a hole blocking layer on the photoactive layer; and forming a hole transport layer on the hole blocking layer.

[0009] In a method for manufacturing a perovskite photodetector according to the present invention, the step of forming an electron transport layer may comprise: (a) a step of depositing an organic tin precursor on the substrate; (b) a step of purging by injecting an inert gas; (c) a step of injecting an oxygen source; and (d) a step of manufacturing a tin oxide thin film by injecting an inert gas and purging.

[0010] In the method for manufacturing a perovskite photodetector according to the present invention, steps (a) to (d) may be used as unit processes, and the unit processes may be repeated 100 to 500 times.

[0011] In the method for manufacturing a perovskite photodetector according to the present invention, after step (d), (e) a step of heat-treating the tin oxide thin film may be further included.

[0012] In the method for manufacturing a perovskite photodetector according to the present invention, the heat treatment may be performed under a temperature condition of 200 to 400°C.

[0013] In the method for manufacturing a perovskite photodetector according to the present invention, the step of forming the photoactive layer may be performed by further adding an anti-solvent while applying a perovskite precursor solution onto the electron transport layer.

[0014] In the method for manufacturing a perovskite photodetector according to the present invention, the anti-solvent may be introduced 1 to 60 seconds before the coating of the perovskite precursor solution is completed.

[0015] In the method for manufacturing a perovskite photodetector according to the present invention, the step of forming a hole blocking layer may be to apply a polyimide (PI) containing solution onto the photoactive layer.

[0016] In the method for manufacturing a perovskite photodetector according to the present invention, the polyimide-containing solution may contain polyimide in an amount of 0.2 to 1.4 mg / ml.

[0017] In a method for manufacturing a perovskite photodetector according to the present invention, after the step of forming a hole transport layer, the method may further include the step of forming a second electrode on the hole transport layer.

[0018] The present invention provides a perovskite photodetector, wherein the perovskite photodetector comprises: an electron transport layer containing crystalline tin oxide; a photoactive layer located on the electron transport layer and containing a perovskite compound; a hole transport layer located on the photoactive layer; and a hole blocking layer located between the photoactive layer and the hole transport layer.

[0019] In the perovskite photodetector according to the present invention, in the X-ray diffraction (XRD) spectrum of the electron transport layer, the intensity of the peak detected at 2θ=44±0.5˚ may be 70% or more of the maximum peak in the entire diffraction pattern.

[0020] In the perovskite photodetector according to the present invention, the hole blocking layer may contain polyimide (PI).

[0021] In the perovskite photodetector according to the present invention, the dark current value is 20 nA / cm² based on a voltage of -0.3V. 2 It may be less than

[0022] In the perovskite photodetector according to the present invention, the perovskite compound may comprise one or more selected from the following chemical formulas 1 to 3.

[0023] [Chemical Formula 1]

[0024] (A a x A b 1-x )B(X a y X b 1-y )3(0≤x≤0.7, 0≤y≤1)

[0025] [Chemical Formula 2]

[0026] (A a x A b 1-x-z M a )B(X ay X b 1-y )3(0≤z≤0.3, 0.3≤x≤0.7, 0≤y≤1)

[0027] [Chemical Formula 3]

[0028] (A a 1-x-z A b x M z )B(X a y X b 1-y )3(0≤x+z≤1, 0≤y≤1)

[0029] (In the above chemical formulas 1 to 3, A a and A b Each is independently a monovalent organic cation, and M is Cs + , Rb + or alkali metal cations comprising a combination thereof, B is a divalent metal cation and X a and X b Each independently represents a halogen anion)

[0030] In a perovskite photodetector according to the present invention, the perovskite compound is (FA x MA 1x )Pb(I 0.3 Br 0.7 )3(0≤x≤0.7), (MA 0.95-x FA x Cs 0.05 )Pb(Br 0.6 Cl 0.4 )3(0.3≤x≤0.8) and (FA 0.95-x MA x Cs 0.05 )Pb(Br 0.6 Cl 0.4 It may contain one or more selected from the group including )3 (0≤x≤0.95).

[0031] A perovskite photodetector according to the present invention may further comprise a first electrode located below the electron transport layer; and a second electrode located above the hole transport layer. Effects of the invention

[0032] The perovskite photodetector of the present disclosure and the method for manufacturing the same provide a perovskite photodetector and a method for manufacturing the same that can significantly improve the performance of the device by improving the response speed of the device and suppressing dark current by including an electron transport layer having high crystallinity and minimized surface defects. Brief explanation of the drawing

[0033] FIG. 1 is a flowchart illustrating a method for manufacturing a perovskite photodetector according to one embodiment of the present disclosure. FIG. 2 is a schematic diagram illustrating a perovskite photodetector according to one embodiment of the present disclosure. FIG. 3 is a graph showing the dark current measurement results of perovskite photodetectors prepared by the methods according to Examples 1 to 3 and Comparative Examples 1 to 3. Figure 4 is a graph showing the measured dark current of a perovskite photodetector prepared by the method according to Example 1, Example 4, and Example 5. Figure 5 is an X-ray reflectometry (XRR) measurement spectrum for the electron transport layer of a perovskite photodetector prepared by the method according to Example 1. Figure 6 is an X-ray diffraction (XRD) analysis spectrum of the electron transport layer of a perovskite photodetector prepared by the method according to Examples 1 and 6 to 8. Figure 7 is a graph showing the measured dark current of a perovskite photodetector prepared by the method according to Examples 9 to 12. Figure 8 is a graph showing the measured dark current of perovskite photodetectors prepared by the methods according to Example 1 and Example 3, respectively. Specific details for implementing the invention

[0034] The terms used in this specification have been selected to be as widely used as possible, taking into account the function of this disclosure; however, these terms may vary depending on the intent of those skilled in the relevant field, case law, the emergence of new technologies, etc. Unless otherwise defined, technical and scientific terms used may have the meaning commonly understood by those skilled in the art to which this invention pertains.

[0035] In this specification and the appended claims, terms such as “comprising” or “having” mean that the features or components described in the specification exist, and unless specifically limited, do not preclude the possibility that one or more other features or components may be added.

[0036] In this specification and the appended claims, terms such as "first," "second," etc. are used not in a limiting sense, but for the purpose of distinguishing one component from another.

[0037] Singular expressions used in this specification and the appended claims include plural expressions unless the context clearly indicates that they are singular. Additionally, plural expressions include singular expressions unless the context clearly indicates that they are plural.

[0038] Additionally, numerical ranges used herein include lower and upper limits and all values ​​within the range, increments logically derived from the form and width of the defined range, all of which are limited values, and all possible combinations of upper and lower limits of numerical ranges defined in different forms. Unless otherwise specifically defined in the specification of this disclosure, values ​​outside the numerical range that may occur due to experimental error or rounding of values ​​are also included in the defined numerical range.

[0039] Terms such as "approximately" used in this specification and the appended claims are used to encompass tolerances when tolerances exist.

[0040] Hereinafter, the perovskite photodetector of the present disclosure and the method for manufacturing the same will be described in detail.

[0041] A method for manufacturing a perovskite photodetector according to the present disclosure comprises, as illustrated in FIG. 1, a step of forming an electron transport layer by depositing an organic tin precursor on a first electrode by atomic layer deposition; a step of forming a photoactive layer by applying a perovskite precursor solution on the electron transport layer; a step of forming a hole blocking layer on the photoactive layer; and a step of forming a hole transport layer on the hole blocking layer.

[0042] When a perovskite photodetector is manufactured using the method described above, the film quality of the electron transport layer is particularly improved, and a highly crystalline electron transport layer with a developed crystal structure on a specific plane can be manufactured. In addition, due to the synergistic effect between the hole blocking layer formed on the photoactive layer and the electron transport layer described above, the perovskite photodetector containing them can effectively suppress the dark current density in a wide wavelength range spanning red light in the 600 to 800 nm wavelength range, green light in the 500 to 600 nm wavelength range, and blue light in the 400 to 500 nm wavelength range, and can have a high response speed.

[0043] The electron transport layer formation step described above can be performed using atomic layer deposition. Atomic layer deposition is a process in which a thin film is deposited through a self-limiting surface reaction in which one atomic layer is deposited per cycle, enabling the production of a very uniform and dense tin oxide thin film. As such, the electron transport layer thin film with significantly improved film quality has minimized surface defects and possesses high crystallinity, thereby improving the interfacial stability with the photoactive layer in contact with the electron transport layer and promoting electron transport. Furthermore, since current flows even when light energy is not applied, it can effectively suppress the dark current phenomenon, which acts as noise in the device.

[0044] More specifically, the electron transport layer formation step may include: (a) a step of depositing an organic tin precursor on the substrate; (b) a step of purging by injecting an inert gas; (c) a step of injecting an oxygen source; and (d) a step of manufacturing a tin oxide thin film by purging by injecting an inert gas.

[0045] Steps (a) to (d) above can be used as unit processes, and the unit processes can be repeated 100 to 500 times, 150 to 450 times, 200 to 400 times, or 250 to 350 times. When repeated within the above ranges, the dark current suppression effect can be significantly increased.

[0046] As a more specific example, steps (a) and (c) may each be performed independently for 0.5 to 10 seconds, 1 to 7 seconds, or 2 to 4 seconds, and steps (b) and (d) may each be performed independently for 5 to 30 seconds, 6 to 28 seconds, or 7 to 25 seconds. By performing steps (a) to (d) during the above times, the dark current value of the perovskite photodetector can be effectively lowered.

[0047] The above organotin precursor may include one or more selected from Sn(dmamp)2(bis(1-dimethylamino-2-methyl-2-propoxy) tin(II)), N,N′-tert-butyl-1,1-dimethylethylenediamine stannylene(II)), Sn(edpa)2(bis(N-ethoxy-2,2-dimethylpropanamido) tin), Sn(acetylacetonate)2(Sn(acac)2), Sn(ethylhexanoate)2, Sn(neodecanoate)2, Sn(tert-butoxide)2, and Sn(OCH(CH₃)₂)₂(diisopropoxytin(II)), and preferably, Sn(dmamp)2(bis(1-dimethylamino-2-methyl-2-propoxy) tin(II)) may be included as the organotin precursor.

[0048] The above oxygen source may include H2O, H2O2, and O3, preferably gaseous O3, but the present disclosure is not limited thereto.

[0049] The above inert gas may be used without limitation as long as it is a gas that does not participate in the reaction, and may include, for example, argon (Ar) gas, nitrogen (N2) gas, or a combination thereof, but it goes without saying that the present disclosure is not limited by specific types of inert gases.

[0050] After step (d) above, (e) a step of heat-treating the tin oxide thin film may be further included. A highly crystalline tin oxide thin film can be manufactured by heat-treating a tin oxide thin film after depositing it on the first electrode using atomic layer deposition.

[0051] In one example, the heat treatment may be performed at a temperature of 200 to 400°C, 250 to 350°C, or 280 to 320°C. When heat treatment is performed in the above temperature range, the crystallinity of the tin oxide thin film is improved by converting from amorphous to crystalline, and in particular, as described below, the electron transport capacity can be enhanced as the crystallinity in the (220) plane direction is improved.

[0052] In one example, the first electrode may use a transparent electrode with high light transmittance to facilitate light reception, and may use, for example, ITO (Tin-doped oxide), FTO (F-doped oxide), GZO (Ga-doped Zinc Oxide), ZnO (Zinc Oxide), IZO (Indium Zinc Oxide), AZO (Al-doped Zinc Oxide), graphene, carbon nanotubes, silver nanowires, PEDOT:PSS (poly(3,4-ethylenedioxythiophene):polystyrene sulfonate), etc. without limitation.

[0053] The first electrode may be located on one surface of a transparent substrate, and the transparent substrate may be a glass substrate or a polymer substrate such as PET, but the present disclosure is not limited thereto.

[0054] The photoactive layer formation step may be performed by applying and drying a perovskite precursor solution on the electron transport layer.

[0055] To induce high-purity perovskite crystals, an anti-solvent may be added during the photoactive layer formation step while applying the perovskite precursor solution onto the electron transport layer. The anti-solvent can selectively remove the solvent contained in the perovskite precursor solution applied onto the electron transport layer. By rapidly removing the polar solvent contained in the perovskite precursor solution, crystallization of the perovskite compound can be induced, thereby improving process efficiency.

[0056] In one embodiment, the anti-solvent can be introduced 1 to 60 seconds, 5 to 40 seconds, or 10 to 20 seconds before the coating of the perovskite precursor solution is completed to stably form a photoactive layer.

[0057] The above antisolvent may include a polar aprotic solvent. The polar aprotic solvent can selectively remove the solvent contained in the perovskite precursor solution and minimize the reaction between the perovskite compound and the antisolvent, thereby enabling the formation of high-quality perovskite crystals.

[0058] As an exemplary example, the above antisolvent may comprise one or more selected from the group comprising diethylether (DEE), dipropylether (DPE), cyclohexane, chlorobenzene, toluene, xylene, anisole, and chloroform, and anisole is preferred as the antisolvent when considering combination with the perovskite precursor solution, but the present disclosure is not limited thereto.

[0059] The perovskite precursor is a precursor for forming a perovskite compound, also referred to as an organometal halide having a perovskite structure, comprising an organic cation (A), a metal cation (B), and a halogen anion (X), and may include FABr (formamidinium bromide), FACl (formamidinium chloride), MABr (methyl ammonium bromide), MACl (methyl ammonium chloride), CsBr, and a halide of a metal (B) (e.g., PbBr2, PbCl2). The perovskite precursor powder may be dissolved in a polar solvent to form a perovskite precursor solution.

[0060] As polar solvents, at least one selected from dimethylsulfoxide (DMSO), dimethylformamide (DMF), ethanol, isopropanol, butanol, methanol, benzyl alcohol ethyl acetate, tetrahydrofuran, dichloromethane, acetonitrile, trimethylphosphate, hexamethylphosphoramide, and water may be used, but the present disclosure is not limited by specific types of polar solvents.

[0061] By adjusting the compositional ratio of the components included in the above perovskite precursor solution, a photoactive layer comprising a perovskite compound that selectively absorbs light in a specific wavelength band can be prepared as described below. For instance, perovskite compounds that selectively absorb red light, green light, and blue light, respectively, can be prepared.

[0062] After the photoactive layer formation step, a hole blocking layer is formed on the photoactive layer to improve interface stability between the photoactive layer and the hole transport layer, and the dark current of the perovskite photodetector can be significantly reduced.

[0063] The step of forming the hole blocking layer above may involve applying a polyimide (PI)-containing solution onto the photoactive layer. When the hole blocking layer contains polyimide as an organic polymer, there is an advantage in that the dark current suppression effect is significantly superior due to the synergistic effect resulting from the combination with the electron transport layer, the photoactive layer, and the hole transport layer. The polyimide-containing solution above may be a solution in which polyimide is dispersed in a solvent, and the solvent may include one or more solvents selected from the group comprising N-methyl-2-pyrrolidone (NMP), γ-butyrolactone (GBL), γ-valerolactone (GVL), dimethylacetamide (DMAc), dimethylformamide (DMF), and tetrahydrofuran (THF), but the present disclosure is not limited by specific types of solvents.

[0064] While conventional solution coating methods may be used for the application of the polyimide-containing solution, it is preferable to form a hole blocking layer by applying the polyimide-containing solution using a spin coating method. Using a spin coating method to form a hole blocking layer is preferred because it allows for the formation of a uniform hole blocking layer without degrading the perovskite compound.

[0065] In a specific example, the polyimide-containing solution may contain polyimide in an amount of 0.2 to 1.4 mg / ml, 0.4 to 1.2 mg / ml, 0.6 to 1.0 mg / ml, or 0.6 to 0.8 mg / ml. A uniform hole-blocking layer can be formed on the photoactive layer within the above range.

[0066] After the step of forming a hole blocking layer, a hole transport layer can be formed on the hole blocking layer. The hole transport layer can be prepared by applying and drying a solution containing an organic hole transport material. The above-mentioned organic hole transport materials may be used without limitation as long as they are commonly used in the industry, specifically Spiro-OMeTAD, PEDOT:PSS(poly(3,4-ethylenedioxythiophene):polystyrene sulfonate), Graphene-PEDOT(graphene-poly(3,4-ethylenedioxythiophene)), PANI:PSS(polyaniline:polystyrene), PANI:CSA(camphorsulfonic acid-doped polyaniline), PDBT(Polydibenzothiophene), P3HT(Poly-3-hexylthiophene), PCPDTBT(Poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta [2,1-b;3,4-b′]dithiophene)-alt-4,7(2,1,3-benzothiadiazole)]), It may include one or more selected from PCDTBT (Poly[N-9′-heptadecanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)]), PTAA (Poly(triaryl amine)), MoO3, V2O5, NiO, WO3, CuI, and CuSCN, preferably Spiro-OMeTAD, but the present disclosure is not limited thereto.

[0067] After the step of forming the hole transport layer, the method may further include the step of forming a second electrode on the hole transport layer. The second electrode may be manufactured by thermal evaporation of a conductive material under vacuum conditions.

[0068] The above conductive material may include one or more selected from the group comprising Au, Ag, Pt, Ni, Cu, In, Ru, Pd, Rh, Mo, Ir, Os, C, and conductive polymers, and preferably may be a metal electrode including Au, but it goes without saying that the present disclosure is not limited by the specific type of the second electrode.

[0069] The present disclosure includes a perovskite photodetector manufactured by the method described above. In describing the perovskite photodetector of the present disclosure, the structure, material, and shape of the first electrode, electron transport layer, photoactive layer, hole blocking layer, hole transport layer, and second electrode described above in the method for manufacturing the perovskite photodetector are identical to those described above; therefore, the perovskite photodetector according to the present disclosure includes all the contents described above.

[0070] A perovskite photodetector according to the present disclosure comprises, as illustrated in FIG. 2, an electron transport layer containing crystalline tin oxide; a photoactive layer located on the electron transport layer and containing a perovskite compound; a hole transport layer located on the photoactive layer; and a hole blocking layer located between the photoactive layer and the hole transport layer.

[0071] As described above, the perovskite photodetector of the present disclosure can improve device performance by significantly lowering the dark current and improving the response speed across a wide wavelength range including red light, green light, and blue light through a synergistic effect between the electron transport layer containing highly crystalline tin oxide, the photoactive layer, the hole blocking layer, and the hole transport layer.

[0072] In particular, by including a highly crystalline electron transport layer with a developed crystal structure on a specific plane, the electron transport path can be improved. In addition, since it includes a dense and uniform electron transport layer, surface defects of the electron transport layer are minimized, thereby increasing the contact area with the photoactive layer and further enhancing the effect of improving device performance.

[0073] Specifically, in the X-ray diffraction (XRD) spectrum of the electron transport layer, the relative intensity of the peak detected at 2θ=44±0.5*, that is, the intensity of the peak detected at 2θ=44±0.5* relative to the maximum peak in the entire diffraction pattern, may be 70% or more and / or the FWHM may be 0.2° or less. The peak intensity indicates the crystallinity of the (220) plane of the tin, which may mean that the crystal structure has developed in the plane direction of the electron transport layer.

[0074] Tin oxide thin films with crystals developed along the plane of the electron transport layer have minimized surface defects, which improves interfacial stability with perovskite compounds and can improve electron transport pathways.

[0075] In addition, in one embodiment, the density of the electron transport layer is 3 to 15 g / cm³ 3 , 4 to 14 g / cm² 3 , 5 to 13 g / cm² 3 or 6 to 12 g / cm³ 3 The surface roughness of the electron transport layer may be 0.1 to 1.5 nm, 0.3 to 1.3 nm, or 0.5 to 1.1 nm, and the thickness of the electron transport layer may be 10 to 50 nm, 15 to 45 nm, 20 to 40 nm, or 25 to 35 nm. Since the electron transport layer is dense, smooth, and uniform within the above ranges, the dark current of the perovskite photodetector containing it can be significantly suppressed to improve device performance.

[0076] Specifically, the perovskite photodetector has a dark current value of 20 nA / cm² in the wavelength range of 400 to 800 nm and under an applied voltage of -0.3 V. 2 It may be less than, less than 19 nA / cm2, or less than 18 nA / cm2, and, without limitation, the lower limit of the dark current value is 0.1 nA / cm 2 Above, 0.2 nA / cm2 Above or 0.3 nA / cm 2 It could be more than that.

[0077] By including an electron transport layer having the above-described characteristics and a hole blocking layer containing polyimide, a perovskite photodetector having a significantly low dark current value in wavelength bands corresponding to red light, green light, and blue light can be realized.

[0078] The above photoactive layer may be an organometallic halide having an ABX3, ABX4, A2BX4, or A3BX5 structure containing a monovalent organic cation (A), a divalent metal cation (B), and a halogen anion (X) as a perovskite compound.

[0079] The above monovalent organic cation (A) may include amidinium group ions, organic ammonium ions, or a combination thereof. More specifically, amidinium group ions may include formamidinium (FA) ions, acetamidinium, or guamidinium, and organic ammonium ions may include methylammonium (MA) ions, ethylammonium (Ethylammonium) ions, etc.

[0080] The above monovalent organic cation (A) is, to a limited extent, a monovalent organic cation and a cesium ion (Cs + ), rubidium ion (Rb + It may also be an organic-inorganic complex monovalent cation containing an alkali metal cation including ) or a combination thereof.

[0081] The divalent metal cation (B) is Cr, for example. 2+ , Pd 2+ , Cd 2+ , Ge 2+ , Sn 2+ , Pb 2+ , Cu 2+ , Ni 2+ , Co 2+ , Fe2+ , Mn 2+ and Yb 2+ It may include one or more types selected from among, and the halogen anion (X) is F - , Cl - , Br - and I - It may include one or more types selected from among.

[0082] In a more specific example, the perovskite compound may include one or more selected from the following chemical formulas 1 to 3.

[0083] [Chemical Formula 1]

[0084] (A a x A b 1-x )B(X a y X b 1-y )3(0≤x≤0.7, 0≤y≤1)

[0085] [Chemical Formula 2]

[0086] (A a x A b 1-x-z M a )B(X a y X b 1-y )3(0≤z≤0.3, 0.3≤x≤0.7, 0≤y≤1)

[0087] [Chemical Formula 3]

[0088] (A a 1-x-z A b x M z )B(X a y X b 1-y )3(0≤x+z≤1, 0≤y≤1)

[0089] In the above chemical formulas 1 to 3, A a and A b Each is independently a monovalent organic cation, and M is Cs +, Rb + or alkali metal cations comprising a combination thereof, B is a divalent metal cation and X a and X b Each independently represents a halogen anion, and the monovalent organic cation, divalent metal cation, and halogen anion are the same as those described above.

[0090] The chemical formulas 1 to 3 above are perovskite compounds that selectively absorb red light, green light, and blue light, respectively. By stacking perovskite photodetectors containing perovskite compounds that selectively absorb light of a specific wavelength band, pixels can be integrated without a color filter and quantum efficiency can be maximized.

[0091] As a more specific example, a perovskite compound that selectively absorbs red light as shown in Chemical Formula 1 above is (FA x MA 1x )Pb(I 0.3 Br 0.7 It can be represented as )3(0≤x≤0.7), and a perovskite compound that selectively absorbs green light as in Chemical Formula 2 above is (MA 0.95-x FA x Cs 0.05 )Pb(Br 0.6 Cl 0.4 It can be represented as )3(0.3≤x≤0.8), and a perovskite compound that selectively absorbs blue light as in the above chemical formula 3 is (FA 0.95-x MA x Cs 0.05 )Pb(Br 0.6 Cl 0.4 It can be expressed as )3(0≤x≤0.95).

[0092] Additionally, it may further include a first electrode located below the electron transport layer; and a second electrode located above the hole transport layer.

[0093] The perovskite photodetector according to the present disclosure can be used in various fields such as perovskite solar cells, memory devices, light-emitting devices, memristors, photodiodes, and phototransistors, and preferably provides the best performance when used as a photodiode, but the present disclosure is not limited by the use of the perovskite photodetector.

[0094] The present disclosure will be explained in more detail below through examples.

[0095] (Example 1)

[0096] Substrate preparation: A glass substrate (ITO / Glass) with an ITO (Indium Tin Oxide) deposited thereon measuring 2 cm × 2 cm was prepared. The substrate was immersed in a 2 vol% Hellmanex cleaning solution for 10 minutes, and then sequentially placed into ultrasonic cleaners filled with acetone, distilled water, and isopropyl alcohol, respectively, to perform ultrasonic cleaning for 10 minutes per solvent. Afterward, the substrate was dried using nitrogen gas, and the surface of the substrate was improved and residual organic matter removed through UV / ozone plasma treatment.

[0097] Preparation of electron transport layer: The above substrate was placed in a reaction chamber to prepare a tin oxide thin film by atomic layer deposition. The atomic layer deposition conditions are shown in Table 1 below. During deposition, Sn(dmamp)2 (bis(1-dimethylamino-2-methyl-2-propoxide)Sn) was supplied to the reaction chamber in a pulse form for 3 seconds, after which the supply of Sn(dmamp)2 was stopped, and nitrogen gas was supplied for 7 seconds to purge the substrate to remove residual precursors. Subsequently, ozone (O3) was injected in a pulse for 3 seconds, after which the supply of ozone (O3) was stopped, and nitrogen gas was supplied for 7 seconds to purge the substrate. Using the above process as a unit process (cycle), the unit process was repeated for 300 cycles to deposit a tin oxide thin film on the substrate. Subsequently, the deposited tin oxide thin film was heat-treated at 300°C to prepare an electron transport layer.

[0098] Reactor pressure 0.7 Torr RF power 100 W Sn(dmamp)2 flow rate 20 sccm Nitrogen gas flow rate 150 sccm Ozone flow rate 100 sccm Substrate temperature 150 ℃ deposition rate 1.2 Å / cycle

[0099] Preparation of photoactive layer: Using a perovskite precursor with a red light absorption composition (FA x MA 1x )Pb(I 0.3 Br 0.7 )3 (0≤x≤0.7) was dissolved at a concentration of 1.5 M in a mixed solvent containing 0.5 mL of dimethylformamide (DMF) and 0.5 mL of dimethylsulfoxide (DMSO). Before use, all solutions were filtered through a 0.2 μm PTFE membrane. Subsequently, the perovskite precursor solution was spin-coated onto the electron transport layer at 4000 rpm for 25 seconds. Anisole was added 15 seconds before the spin-coating was completed. Afterward, the perovskite photoactive layer was prepared by heat treatment at 100°C for 10 minutes.

[0100] Preparation of hole blocking layer: Polyimide (manufacturer: Sigma-Aldrich, product name: PI-2545), a dispersion stabilizer (polyvinylpyrrolidone, PVP), and a surface modifier (3-aminopropyltriethoxysilane, APTES) were added to chlorobenzene, and a homogeneous mixed solution was prepared by stirring at 500 rpm for 12 hours.

[0101] The above-described mixed solution was spin-coated at 2,000 rpm for 60 seconds, and then heat-treated at 100°C for 10 minutes to form a hole-blocking layer on the photoactive layer.

[0102] At this time, if necessary, the polymer structure of the hole blocking layer can be stabilized and the interfacial adhesion characteristics improved through additional post-heat treatment at 180°C for 30 minutes.

[0103] Preparation of hole transport layer: A solution for preparing a hole transport layer was prepared by mixing a Spiro-OMeTAD solution (90 mg / mL) dissolved in chlorobenzene, 39 µL of 4-tert-butylpyridine, 23 µL of a Li-TFSI solution (520 mg / mL) dissolved in acetonitrile, and 10 µL of tris[2-(1H-pyrazol1-yl)-4-tert-butylpyridine]-cobalt(III)-tris[bis-(trifluoromethylsulfonyl)imide](FK209). A hole transport layer was prepared by spin-coating the solution onto a hole blocking layer at 3000 rpm for 30 seconds.

[0104] Second electrode manufacturing: thereafter, 4 × 10 6 A perovskite photodetector in the form of a photodiode was fabricated by depositing a 100 nm thick gold electrode by thermal evaporation at a pressure of Torr.

[0105] (Example 2)

[0106] When manufacturing the photoactive layer, instead of a perovskite precursor with a red light absorption composition, a perovskite precursor with a green light absorption composition is used (MA 0.95-x FA x Cs 0.05 )Pb(Br 0.6 Cl 0.4 A perovskite photodetector was prepared by performing the same method as in Example 1, except that )3 (0.3≤x≤0.8) was used.

[0107] (Example 3)

[0108] When manufacturing the photoactive layer, instead of a perovskite precursor with a red light absorption composition, a perovskite precursor with a blue light absorption composition is used (FA 0.95-x MA x Cs 0.05 )Pb(Br 0.6 Cl 0.4 A perovskite photodetector was prepared by performing the same method as in Example 1, except that )3 (0≤x≤0.95) was used.

[0109] (Example 4)

[0110] A perovskite photodetector was manufactured in the same manner as in Example 1, except that the unit process was repeated for 100 cycles when manufacturing the electron transport layer.

[0111] (Example 5)

[0112] A perovskite photodetector was manufactured in the same manner as in Example 1, except that the unit process was repeated for 200 cycles when manufacturing the electron transport layer.

[0113] (Example 6)

[0114] A perovskite photodetector was manufactured in the same manner as in Example 1, except that the tin oxide was heat-treated at 80°C when manufacturing the electron transport layer.

[0115] (Example 7)

[0116] A perovskite photodetector was manufactured in the same manner as in Example 1, except that the tin oxide was heat-treated at 180°C when manufacturing the electron transport layer.

[0117] (Example 8)

[0118] A perovskite photodetector was manufactured in the same manner as in Example 1, except that the tin oxide was heat-treated at 500°C when manufacturing the electron transport layer.

[0119] (Example 9)

[0120] A perovskite photodetector was prepared in the same manner as in Example 3, except that oleylamine (product name: Oleylamine technical grade 70%, manufacturer: Sigma-Aldrich) was used instead of polyimide when preparing the hole blocking layer.

[0121] (Example 10)

[0122] A perovskite photodetector was manufactured in the same manner as in Example 3, except that oleic acid (product name: Oleic acid technical grade 90%, manufacturer: Sigma-Aldrich) was used instead of polyimide when manufacturing the hole blocking layer.

[0123] (Example 11)

[0124] A perovskite photodetector was prepared in the same manner as in Example 2, except that phenylethylamine (PEA, product name: 2-Phenylethylamine 99%, manufacturer: TCI) was used instead of polyimide when preparing the hole blocking layer.

[0125] (Example 12)

[0126] A perovskite photodetector was manufactured in the same manner as in Example 2, except that polymethyl methacrylate (PMMA, product name: PMMA average Mw ~120,000, manufacturer: Sigma-Aldrich) was used instead of polyimide when manufacturing the hole blocking layer.

[0127] (Comparative Example 1)

[0128] A perovskite photodetector was prepared by performing the same method as in Example 1, except that the SnO2 colloidal solution was diluted to 2.5 wt% in distilled water, the SnO2 colloidal solution was applied to a substrate by spin coating at 3000 rpm for 30 seconds, and then heat-treated at 150°C for 10 minutes to prepare an electron transport layer.

[0129] (Comparative Example 2)

[0130] When manufacturing the photoactive layer, instead of a perovskite precursor with a red light absorption composition, a perovskite precursor with a green light absorption composition is used (MA 0.95-x FA x Cs 0.05 )Pb(Br 0.6 Cl 0.4 A perovskite photodetector was prepared by performing the same method as Comparative Example 1, except that )3 (0.3≤x≤0.8) was used.

[0131] (Comparative Example 3)

[0132] When manufacturing the photoactive layer, instead of a perovskite precursor with a red light absorption composition, a perovskite precursor with a blue light absorption composition is used (FA 0.95-x MA x Cs 0.05 )Pb(Br 0.6 Cl 0.4 A perovskite photodetector was prepared by performing the same method as Comparative Example 1, except that )3 (0≤x≤0.95) was used.

[0133] (Comparative Example 4)

[0134] A perovskite photodetector was manufactured in the same manner as in Example 1, except that a hole blocking layer was not formed.

[0135] Physical Property Evaluation Methods

[0136] 1. Dark current measurement

[0137] Dark current was measured to evaluate the leakage current characteristics of the device in a dark room environment without an external light source. Measurements were performed using a Keithley 4200-SCS semiconductor parameter analyzer, which was coupled with a precision mechanical probe station. Current density (J)-voltage (V) curves were measured by applying voltage in a dark condition. For quantitative analysis, the dark region of the device was defined as 0.364 cm², which was measured separately from the photoresponsive region (0.14 cm²). During dark current measurement, forward and reverse biases were sequentially applied to the device within the range of -1 V to +1 V, and the corresponding current values ​​were recorded. Additionally, the dark current measurements were utilized to evaluate the device's signal-to-noise ratio (SNR) and leakage current suppression characteristics by comparing them with photocurrent measurements performed under the same conditions.

[0138] 2. X-ray Reflectometry (XRR) Measurement

[0139] When fabricating a perovskite photodetector, the X-ray reflectometry (XRR) of a sample having an electron transport layer formed on a substrate was measured and is shown in Fig. 5 below. The XRR measurement was performed using a Bruker D8 Discover model under the following conditions.

[0140] - Wavelength: 1.540593 Å

[0141] - Divergence: 0.01 deg

[0142] - 2-theta offset: 0.0 deg

[0143] - scale factor: 1.0

[0144] - background parameter: 1 X e -10

[0145] 3. X-ray Diffraction (XRD) Analysis

[0146] During the fabrication of perovskite photodetectors, XRD analysis was performed on samples in which an electron transport layer was formed on a substrate to confirm the surface crystal structure of the electron transport layer. Specifically, XRD analysis was performed using the Bruker D8 Advance model under the following conditions.

[0147] - Light Source (X-ray Source): Cu-Kα radiation

[0148] - Power: 40 KV x 30mA

[0149] - Mode: Continuous Scan Mode

[0150] - Scan angle range: 10°~50°

[0151] - Scan speed: 5° / min

[0153] Figure 3 is a graph showing the dark current measurement results of perovskite photodetectors prepared by the methods according to Examples 1 to 3 and Comparative Examples 1 to 3, respectively. As shown in Figure 3, the perovskite photodetectors of Examples 1 to 3, in which the electron transport layer was prepared using atomic layer deposition, showed a dark current value that was more than 10 times lower than that of the perovskite photodetectors of Comparative Examples 1 to 3, in which the electron transport layer was prepared by spin coating a tin oxide-containing solution, in all red, green, and blue light wavelength bands.

[0154] Figure 4 is a graph showing the measured dark current of perovskite photodetectors prepared by the methods according to Examples 1, 4, and 5, respectively. The dark current was measured in the red light wavelength band of ?? to ?? nm. When preparing the electron transport layer, the perovskite photodetector of Example 1, in which the unit process was repeated 300 times to prepare the electron transport layer, exhibited a significantly lower dark current value compared to Examples 4 and 5, in which the unit process was performed 100 and 200 times, respectively. Specifically, compared to Example 4, approximately 10 at -0.3V 2 It was confirmed that the dark current suppression effect was most excellent when the unit process was repeated 300 times, exhibiting a dark current value that was about twice as low.

[0155] FIG. 5 is the X-ray reflectometry (XRR) measurement spectrum of the electron transport layer prepared by the method according to Example 1. Referring to FIG. 5, the density of the electron transport layer is 6.474 g / cm³. 3 It was confirmed that a dense and uniform highly crystalline tin oxide thin film was formed, with a surface roughness of 1.071 nm and a thickness of 28 nm.

[0156] FIG. 6 is the XRD analysis spectrum of the electron transport layer of the perovskite photodetector prepared by different methods in Examples 1 and 6 to 8. Examples 6 and 7, which contain electron transport layers prepared by heat-treating tin oxide thin films at 80°C and 180°C, respectively, were confirmed to have low crystallinity as signals related to amorphous Sn were detected. On the other hand, as the heat treatment temperature increased above 300°C, the crystallinity of the thin film was significantly improved, and in particular, in the case of Example 1, which was heat-treated at 300°C, the diffraction peak intensity corresponding to the (220) plane was higher than that of Example 8, which was heat-treated at 500°C. This suggests that under the intermediate temperature condition of 300°C, the tin oxide thin film induces preferential crystal growth in a specific plane direction. Accordingly, tin oxide thin films with improved crystallinity exhibit enhanced interfacial stability with the perovskite active layer as surface defect density decreases, and the development of specific crystal planes induces alignment of electron transport pathways, contributing to improved electron extraction efficiency of the device. Consequently, a highly crystallin electron transport layer can contribute to the improvement of performance and reliability of perovskite photodetectors.

[0157] FIG. 7 is a graph showing the measured dark current of perovskite photodetectors prepared by the methods according to Examples 9 to 12, respectively, and FIG. 8 is a graph showing the measured dark current of perovskite photodetectors prepared by the methods according to Examples 1 and 3. The dark current of the perovskite photodetectors of Examples 9 to 12 is 332 nA / cm² at -0.3V, respectively. 2 , 162 µA / cm 2 , 156 µA / cm 2 and 34.7 nA / cm 2 Although measured as such, the perovskite photodetectors of Examples 1 and 3 were 13.76 nA / cm², respectively, at -0.3V. 2 and 17.32 nA / cm 2It exhibited a low dark current. It was confirmed that the dark current suppression effect varied significantly depending on the specific type of hole blocking layer, and among them, the most excellent dark current suppression effect was observed when polyimide was used. Although not shown in Figs. 7 and 8, the perovskite photodetector of Comparative Example 4, which does not include a hole blocking layer, had a dark current of 546 μA / cm² at -0.3V. 2 It was significantly high.

[0158] As described above, the present invention has been explained by specific details, limited embodiments, and drawings; however, this is provided merely to aid in a more comprehensive understanding of the invention and is not limited to the above embodiments. Those skilled in the art can make various modifications and variations from this description.

[0159] Accordingly, the scope of the present invention is not limited to the described embodiments, and all things equivalent to or having equivalent variations to the claims set forth below, as well as the claims set forth below, shall be considered to fall within the scope of the concept of the present invention.

Claims

Claim 1 A method for manufacturing a perovskite photodetector, comprising: a step of forming an electron transport layer by depositing an organic tin precursor on a first electrode by atomic layer deposition; a step of forming a photoactive layer by applying a perovskite precursor solution on the electron transport layer; a step of forming a hole blocking layer on the photoactive layer; and a step of forming a hole transport layer on the hole blocking layer; wherein the step of forming the photoactive layer is performed by further adding an anti-solvent while applying the perovskite precursor solution on the electron transport layer. Claim 2 A method for manufacturing a perovskite photodetector according to claim 1, wherein the step of forming the electron transport layer comprises: (a) a step of depositing an organic tin precursor on a substrate; (b) a step of purging by injecting an inert gas; (c) a step of injecting an oxygen source; and (d) a step of manufacturing a tin oxide thin film by injecting an inert gas and purging. Claim 3 A method for manufacturing a perovskite photodetector according to claim 2, wherein steps (a) to (d) are used as unit processes, and the unit processes are repeated 100 to 500 times. Claim 4 A method for manufacturing a perovskite photodetector according to claim 2, further comprising, after step (d), (e) a step of heat-treating the tin oxide thin film. Claim 5 A method for manufacturing a perovskite photodetector according to claim 4, wherein the heat treatment is performed under temperature conditions of 200 to 400°C. Claim 6 delete Claim 7 A method for manufacturing a perovskite photodetector according to claim 1, wherein the anti-solvent is introduced 1 to 60 seconds before the coating of the perovskite precursor solution is completed. Claim 8 A method for manufacturing a perovskite photodetector, wherein, in claim 1, the step of forming a hole blocking layer is to apply a polyimide (PI) containing solution onto the photoactive layer. Claim 9 A method for manufacturing a perovskite photodetector according to claim 8, wherein the polyimide-containing solution contains 0.2 to 1.4 mg / ml of polyimide. Claim 10 A method for manufacturing a perovskite photodetector, wherein, in claim 1, after the step of forming the hole transport layer, a second electrode is formed on the hole transport layer. Claim 11 A perovskite photodetector comprising: an electron transport layer containing crystalline tin oxide; a photoactive layer located on the electron transport layer and containing a perovskite compound; a hole transport layer located on the photoactive layer; and a hole blocking layer located between the photoactive layer and the hole transport layer; wherein, in the X-ray diffraction (XRD) spectrum of the electron transport layer, the intensity of the peak detected at 2θ±0.5˚ is 70% or more relative to the maximum peak of the entire diffraction pattern. Claim 12 delete Claim 13 A perovskite photodetector according to claim 11, wherein the hole blocking layer contains polyimide (PI). Claim 14 In claim 11, the perovskite photodetector has a dark current density of 20 nA / cm² under an applied voltage of -0.3 V. 2 Perovskite photodetector less than Claim 15 A perovskite photodetector according to claim 11, wherein the perovskite compound comprises one or more selected from the following chemical formulas 1 to 3. [Chemical Formula 1] (A a x A b 1-x )B(X a y X b 1-y )3(0≤x≤0.7, 0≤y≤1)[Chemical Formula 2](A a x A b 1-x-z M a )B(X a y X b 1-y )3(0≤z≤0.3, 0.3≤x≤0.7, 0≤y≤1)[Chemical Formula 3](A a 1-x-z A b x M z )B(X a y X b 1-y )3(0≤x+z≤1, 0≤y≤1)(in the above chemical formulas 1 to 3, A a and A b Each is independently a monovalent organic cation, and M is Cs + , Rb + or alkali metal cations comprising a combination thereof, B is a divalent metal cation and X a and X b Each independently represents a halogen anion) Claim 16 In paragraph 15, the above perovskite compound is (FA x MA 1x )Pb(I 0.3 Br 0.7 )3(0≤x≤0.7), (MA 0.95-x FA x Cs 0.05 )Pb(Br 0.6 Cl 0.4 )3(0.3≤x≤0.8) and (FA 0.95-x MA x Cs 0.05 )Pb(Br 0.6 Cl 0.4 A perovskite photodetector containing one or more selected from the group including )3 (0≤x≤0.95). Claim 17 A perovskite photodetector according to claim 11, further comprising: a first electrode located below the electron transport layer; and a second electrode located above the hole transport layer.

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