Multi-channel spectrum-sensitive high-speed communication perovskite photovoltaic device and its manufacturing method

Abstract

The present invention relates to a perovskite photodetector that responds to light in a broad light band including the visible light and infrared regions, and has high responsivity and high detection capability, and a method for manufacturing the same. A perovskite photodetector according to the present invention comprises a perovskite thin film; and a charge transfer layer stacked on the perovskite thin film, wherein the charge transfer layer comprises an organic acceptor having one or more conjugated structures, and the band gap of the organic acceptor is 1.3 eV or less.

Description

Technology Field

[0001] The present invention relates to a perovskite photodetector that responds to light in a broad light band including the visible light and infrared regions, and has high responsivity and high detection capability, and a method for manufacturing the same. Background Technology

[0002] Organic-inorganic hybrid perovskite materials are attracting attention as key materials for next-generation optoelectronic devices due to their advantages, such as high light absorption, high external quantum efficiency (EQE), fast charge transfer rates, and solution processability. Over the past decade, extensive research has been conducted on perovskite materials, primarily focusing on solar cells, and they are on the verge of commercialization, with peak photoelectric conversion efficiencies reaching 25%. However, active research is still underway to address numerous challenges that remain for the commercialization of perovskite solar cells, such as improving stability against light, heat, and moisture, enhancing charge transfer efficiency, reducing toxic substances, and developing low-cost, large-area perovskite thin film manufacturing methods.

[0003] Recently, perovskite photodetectors that enable optical communication based on the high photoelectric efficiency of perovskite active layers have been attracting attention. Perovskite active layers possess high photocurrents, resulting in a high On / Off ratio and excellent detection capabilities, as well as the advantage of high light absorption efficiency in the visible light region. However, while recent technologies such as artificial intelligence, machine learning, and the Internet of Things are increasing the demand for photodetectors with high response rates and detection capabilities in the infrared region, the aforementioned perovskite active layers have very low responsiveness in the infrared region, which limits their applicability. The problem to be solved

[0004] The object of the present invention is to provide a perovskite photodetector having high photoresponsivity and high detection capability, and a method for manufacturing the same.

[0005] Another objective of the present invention is to provide a perovskite photodetector that responds to light in a wide range of wavelength bands including visible light and infrared light, and a method for manufacturing the same.

[0006] Another objective of the present invention is to provide a perovskite photodetector suitable for high-speed communication having high photoresponse sensitivity and a method for manufacturing the same. means of solving the problem

[0007] The present invention provides a perovskite photodetector, wherein the perovskite photodetector comprises a perovskite thin film; and a charge transfer layer stacked on the perovskite thin film, wherein the charge transfer layer comprises an organic acceptor having one or more conjugated structures, and the band gap of the organic acceptor is 1.3 eV or less.

[0008] In the perovskite photodetector according to the present invention, the charge transfer layer may further include an organic donor having one or more conjugated structures.

[0009] In the perovskite photodetector according to the present invention, the charge transfer layer may have a bulk heterojunction structure comprising the organic acceptor and the organic donor.

[0010] In the perovskite photodetector according to the present invention, the perovskite thin film may include a perovskite crystal represented by the following chemical formula 1 or chemical formula 2.

[0011] (Chemical Formula 1)

[0012] ABX3

[0013] (Chemical Formula 2)

[0014] A2BX4

[0015] (In the above Chemical Formulas 1 and 2, A is a monovalent alkylammonium cation; a monovalent amidinium cation; Li + ; Na + ; K + ; Rb + ; Cs + ; Fr + ; Cu(I) + ; Ag(I) + and Au(I) + It comprises one or more monovalent cations selected from the group consisting of combinations of, where B is a divalent metal cation, and X is I - , Br - , Cl - Or it is a halogen anion, which is a combination of these.)

[0016] In the perovskite photodetector according to the present invention, the bandgap of the perovskite thin film may be 1.3 eV or higher.

[0017] In the perovskite photodetector according to the present invention, the perovskite photodetector may have a responsivity of 5 mA / W or more to light of any one wavelength in the wavelength range of 750 to 2500 nm.

[0018] In the perovskite photodetector according to the present invention, the organic acceptor may be a non-fullerene acceptor (NFA).

[0019] In the perovskite photodetector according to the present invention, the organic acceptor may be a non-fullerene acceptor satisfying the following chemical formula 3.

[0020] (Chemical Formula 3)

[0021] A-DA'DA

[0022] (In Chemical Formula 3, A and A' are each the same or different electron withdrawing groups, D is each the same or different electron donating group, and DA'D is an electron-deficient core located at the center of the molecule.)

[0023] In the perovskite photodetector according to the present invention, the organic acceptor may include one or more chemical species selected from the group comprising COTIC-4F, COTCN2, and derivatives thereof.

[0024] The present invention provides a method for manufacturing a perovskite photodetector, wherein the method for manufacturing the perovskite photodetector comprises the step of applying a charge transfer layer solution containing one or more organic acceptor molecules having a conjugated structure onto a perovskite thin film; and wherein the band gap of the organic acceptor molecules is 1.3 eV or less.

[0025] In the method for manufacturing a perovskite photodetector according to the present invention, the charge transfer layer solution may further include one or more organic donors having a conjugated structure.

[0026] In the method for manufacturing a perovskite photodetector according to the present invention, the perovskite thin film may include a perovskite crystal represented by the following chemical formula 1 or chemical formula 2.

[0027] (Chemical Formula 1)

[0028] ABX3

[0029] (Chemical Formula 2)

[0030] A2BX4

[0031] (In the above Chemical Formulas 1 and 2, A is a monovalent alkylammonium cation; a monovalent amidinium cation; Li + ; Na + ; K + ; Rb + ; Cs+ ; Fr + ; Cu(I) + ; Ag(I) + and Au(I) + It comprises one or more monovalent cations selected from the group consisting of combinations of, where B is a divalent metal cation, and X is I - , Br - , Cl - Or it is a halogen anion, which is a combination of these.)

[0032] In the method for manufacturing a perovskite photodetector according to the present invention, the organic acceptor may be a non-fullerene acceptor (NFA).

[0033] In the method for manufacturing a perovskite photodetector according to the present invention, the organic acceptor may be a non-fullerene acceptor satisfying the following chemical formula 3.

[0034] (Chemical Formula 3)

[0035] A-DA'DA

[0036] (In Chemical Formula 3, A and A' are each the same or different electron withdrawing groups, D is each the same or different electron donating group, and DA'D is an electron-deficient core located at the center of the molecule.)

[0037] In the method for manufacturing a perovskite photodetector according to the present invention, the organic acceptor may include one or more chemical species selected from the group comprising COTIC-4F, COTCN2, and derivatives thereof. Effects of the invention

[0038] The perovskite photodetector according to the present invention can have high photoresponsivity and high detection capability.

[0039] The perovskite photodetector according to the present invention can respond to light in a wide range of wavelength bands, including visible light and infrared light.

[0040] The perovskite photodetector according to the present invention has high photoresponse sensitivity and can operate as a photosensor suitable for high-speed communication. Brief explanation of the drawing

[0041] FIG. 1 is a diagram illustrating the chemical structure of COTIC-4F according to one embodiment of the present invention. FIG. 2 is a diagram illustrating the chemical structures of PBDT-TT (left side of FIG. 2) and PBDTO-TT (right side of FIG. 2) according to one embodiment of the present invention. FIG. 3 shows the driving current of the perovskite photodetector according to Example 1 as dark current (left) and light of a wavelength of 525 nm (light intensity 17 mW / cm²). 2 )(interrupted) and light of 940 nm wavelength (light intensity 22 mW / cm² 2 This is a drawing that was measured and illustrated under (right). FIG. 4 shows the driving current of the perovskite photodetector according to Example 2 as dark current (left) and light of a wavelength of 525 nm (light intensity 17 mW / cm²). 2 )(interrupted) and light of 940 nm wavelength (light intensity 22 mW / cm² 2 This is a drawing that was measured and illustrated under (right). FIG. 5 shows the driving current of the perovskite photodetector according to Example 3 as dark current (left) and light of a wavelength of 525 nm (light intensity 17 mW / cm²). 2 )(interrupted) and light of 940 nm wavelength (light intensity 22 mW / cm² 2 This is a drawing that was measured and illustrated under (right). Figure 6 is a figure showing the photoresponse profile for each bias at a wavelength of 625 nm of light of a perovskite photodetector according to Example 1. Figure 7 is a figure showing the photoresponse profile for each bias at a wavelength of 625 nm of light of a perovskite photodetector according to Example 2. Figure 8 is a figure showing the photoresponse profile for each bias at a wavelength of 625 nm of light of a perovskite photodetector according to Example 3. FIG. 9 is a figure showing the photoresponse profile for each bias at a wavelength of 940 nm of light of a perovskite photodetector according to Example 1, measured and illustrated. FIG. 10 is a figure showing the photoresponse profile for each bias at a wavelength of 940 nm of light of a perovskite photodetector according to Example 2. FIG. 11 is a figure showing the photoresponse profile for each bias at a wavelength of 940 nm of light of a perovskite photodetector according to Example 3. FIG. 12 is a figure showing the photoresponse profile of a perovskite photodetector according to Comparative Example 1 at a wavelength of 940 nm. FIG. 13 is a diagram showing the measured photoresponse bandwidth of a perovskite photodetector according to Comparative Example 1 at a wavelength of 625 nm. Figure 14 is a diagram showing the measured photoresponse bandwidth of a perovskite photodetector according to Comparative Example 1 at a wavelength of 940 nm. FIG. 15 is a figure showing the measured photoresponse bandwidth for light at a wavelength of 625 nm of a perovskite photodetector (-1 V bias) according to Example 1 (COTIC-4F + PBDT-TT), Example 2 (COTIC-4F + PBDTO-TT), and Example 3 (COTIC-4F). FIG. 16 is a figure showing the measured photoresponse bandwidth for light at a wavelength of 940 nm of a perovskite photodetector (-1 V bias) according to Example 1 (COTIC-4F + PBDT-TT), Example 2 (COTIC-4F + PBDTO-TT), and Example 3 (COTIC-4F). FIG. 17 is a diagram showing the measured photoresponse curves of a perovskite photodetector according to Example 1 for light at wavelengths of 625 nm (outer graph) and 940 nm (inner box graph). FIG. 18 is a diagram showing the measured photoresponse curves of a perovskite photodetector according to Example 2 for light at wavelengths of 625 nm (outer graph) and 940 nm (inner box graph). FIG. 19 is a diagram showing the measured photoresponse curves of a perovskite photodetector according to Example 3 for light at wavelengths of 625 nm (outer graph) and 940 nm (inner box graph). FIG. 20 is a diagram showing the response of a perovskite photodetector according to Example 1. FIG. 21 is a diagram showing the response of a perovskite photodetector according to Example 2. FIG. 22 is a diagram showing the response of a perovskite photodetector according to Example 3. Specific details for implementing the invention

[0042] The embodiments described in this specification may be modified in various different forms, and the technology according to one embodiment is not limited to the embodiments described below. Furthermore, the embodiments of one embodiment are provided to more fully explain the present disclosure to those with average knowledge in the relevant technical field. Unless otherwise defined, technical and scientific terms used herein have the meanings commonly understood by those with ordinary knowledge in the technical field to which this invention pertains, and descriptions of known functions and configurations that may unnecessarily obscure the essence of the present invention are omitted in the following description and accompanying drawings.

[0043] Additionally, the singular form used in this specification and the appended claims may be intended to include the plural form unless specifically indicated otherwise in the context.

[0044] Furthermore, 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.

[0045] Furthermore, in this specification and the appended claims, when a part such as a film (layer), region, or component is described as being located “on,” “on top,” “on the upper,” “under,” “on the lower,” or “on the lower” of another part, this includes not only cases where a part is in contact with another part, but also cases where another part exists between the two parts.

[0046] Furthermore, terms such as “approximately,” “substantially,” etc., as used in this specification and the appended claims, are used to mean at or near the stated value when inherent manufacturing and material tolerances are presented in the said sense, and are used to prevent unscrupulous infringers from unfairly exploiting the disclosure in which precise or absolute values ​​are mentioned to aid in understanding this specification and the appended claims.

[0047] Additionally, numeric ranges used in this specification include lower and upper limits and all values ​​within the range, increments logically derived from the shape and width of the defined range, all of which are limited values, and all possible combinations of upper and lower limits of numeric ranges limited in different forms.

[0048] In addition, the responsiveness in the present invention can be defined as shown in Equation 1 below.

[0049] (Equation 1)

[0050] R(λ) = I ph / P in

[0051] (In Equation 1, R(λ) represents the responsivity at wavelength λ, and I ph represents the photocurrent ([A]), and P in represents the intensity of incident light (incident optical power, [W]).

[0052] In addition, the detectivity in the present invention refers to the specific detectivity (D * It is recognized as ), and can be defined as Equation 2 below.

[0053] (Equation 2)

[0054] D * = [( A x Δf ) (1 / 2) ] / NEP

[0055] (In Equation 2, D* is specific detectivity[Jones = cmHz) 1 / 2 / W] means, and A is the effective detection area [cm² 2 It means ], Δf represents the bandwidth of the incident light [Hz], and NEP stands for noise equivalent power [W], which refers to the minimum light intensity at which the signal-to-noise ratio becomes 1.

[0056] Furthermore, terms such as "include" or "have" in this specification and the appended claims mean that the features or components described in the specification exist, and unless specifically limited, this does not preclude the possibility that one or more other features or components may be added.

[0057] Hereinafter, the perovskite photodetector of the present invention and the method for manufacturing the perovskite photodetector will be described in detail.

[0058] The present invention provides a perovskite photodetector, wherein the perovskite photodetector comprises a perovskite thin film; and a charge transfer layer stacked on the perovskite thin film, wherein the charge transfer layer comprises one or more organic acceptors having a conjugated structure, and the band gap of the organic acceptors is 1.3 eV or less.

[0059] According to one embodiment, the perovskite thin film may comprise a perovskite crystal represented by the following chemical formula 1 and / or the following chemical formula 2.

[0060] (Chemical Formula 1)

[0061] ABX3

[0062] (Chemical Formula 2)

[0063] A2BX4

[0064] (In the above Chemical Formulas 1 and 2, A is a monovalent alkylammonium cation; a monovalent amidinium cation; Li + ; Na + ; K + ; Rb + ; Cs + ; Fr + ; Cu(I) + ; Ag(I) + and Au(I) + It comprises one or more monovalent cations selected from the group consisting of combinations of, where B is a divalent metal cation, and X is I - , Br- , Cl - Or it is a halogen anion, which is a combination of these.)

[0065] The above perovskite thin film may be a perovskite crystal with a three-dimensional structure satisfying the chemical formula ABX3 and / or a perovskite crystal with a two-dimensional planar structure satisfying the chemical formula A2BX4. The perovskite crystal with the structure and composition described above may exhibit a photoelectric effect when irradiated with light of a specific wavelength band depending on the band gap of the perovskite crystal, and a photodetector can be implemented using this.

[0066] According to one embodiment, the band gap of the organic acceptor molecule may be 1.5 eV or less, 1.4 eV or less, 1.3 eV or less, 1.2 eV or less, or 1.1 eV or less, and as a lower limit, may be 0.5 eV or more, 0.6 eV or more, 0.7 eV or more, 0.8 eV or more, or 0.9 eV or more. Specifically, the band gap of the organic acceptor molecule may be 0.5 to 1.5 eV, 0.6 to 1.4 eV, 0.7 to 1.3 eV, 0.8 to 1.2 eV, or 0.9 to 1.1 eV. The band gap of the organic acceptor molecule may be appropriately selected within the above-described range so that the perovskite photodetector may have high responsivity even to light in the infrared region.

[0067] According to one embodiment, the organic acceptor may be a non-fullerene acceptor (NFA). For example, the organic acceptor may be a non-fullerene acceptor satisfying the following chemical formula 3.

[0068] (Chemical Formula 3)

[0069] A-DA'DA

[0070] (In Chemical Formula 3, A and A' are each the same or different electron withdrawing groups, D is each the same or different electron donating group, and DA'D is an electron-deficient core located at the center of the molecule.)

[0071] As a non-limiting example, the organic acceptor is 2,2'-((2Z,2'Z)-(((4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1-b:3,4-b']dithiophene-2,6-diyl)bis(4-(2-ethylhexyloxy)thiophene-5,2-diyl))bis(methanylylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile(COTIC-4F), It may be an organic acceptor selected from the group comprising 2,2'-((2Z,2'Z)-(((4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1-b:3,4-b']dithiophene-2,6-diyl)bis(5-cyano-4-(2-ethylhexyloxy)thiophene-2,2-diyl))bis(methanylylidene))bis(3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile(COTCN2) and derivatives thereof.

[0072] The above-described non-fullerene acceptor has a narrow bandgap, so the perovskite photodetector can have a high responsiveness to infrared light.

[0073] According to one embodiment, the charge transfer layer may further include an organic donor having one or more conjugated structures. As a non-limiting example, the organic donor may be one or more organic donors selected from the group comprising Poly[[4,8-bis(2-ethylhexyloxy)benzo[1,2-b:4,5-b′thieno[3,2-b]thiophene-2,5-diyl]](PBDT-TT), Poly[[4,8-bis(2-ethylhexyloxy)benzo[1,2-b:4,5-b']dithiophene-2,6-diyl]-alt-[thieno[3,2-b]thiophene-2,5-diyl]](PBDTO-TT), and derivatives thereof.

[0074] According to one embodiment, the charge transfer layer may be a bulk heterojunction structure comprising the organic acceptor and the organic donor. The charge transfer layer may have a sandwich structure comprising a first layer comprising the organic acceptor; and a second layer comprising the organic donor; but advantageously, as a bulk heterojunction structure in which the organic acceptor and the organic donor are randomly dispersed and mixed, it may efficiently separate and / or transport excitons generated from the perovskite thin film and / or excitons generated in the charge transfer layer.

[0075] According to one embodiment, the band gap of the perovskite thin film may be 1.3 eV or higher. The band gap of the perovskite thin film may be 1.0 eV or higher, 1.1 eV or higher, 1.2 eV or higher, 1.3 eV or higher, or 1.4 eV or higher, and as an upper limit, may be 3.0 eV or lower, 2.0 eV or lower, 1.8 eV or lower, 1.9 eV or lower, or 1.8 eV or lower. Specifically, the band gap of the perovskite thin film may be 1.0 to 3.0 eV, 1.1 to 2.0 eV, 1.2 to 1.8 eV, 1.3 to 1.9 eV, or 1.4 to 1.8 eV. The band gap of the perovskite thin film may be appropriately adjusted within the above-described range to have a high visible light reception rate. In addition, the band gap of the perovskite thin film is selected within the range described above, and at the same time, the valence band maximum (VBM) and conduction band minimum (CBM) are appropriately adjusted considering the energy level of the charge transfer layer so that excitons generated in the perovskite thin film can be easily separated and transferred.

[0076] According to one embodiment, the perovskite photodetector may have a responsivity of 5 mA / W or more to light of any wavelength in the 750 to 2500 nm wavelength range. The perovskite photodetector may have a responsivity of 0.1 mA / W or more, 1 mA / W or more, 5 mA / W or more, or 10 mA / W or more to light of any wavelength in the 750 to 2500 nm wavelength range, and as an upper limit, may be 500 mA / W or less, 200 mA / W or less, 100 mA / W or less, or 50 mA / W or less. Specifically, the perovskite photodetector may have a responsiveness to light of any wavelength in the 750 to 2500 nm wavelength range of 0.1 to 500 mA / W, 1 to 200 mA / W, 5 to 100 mA / W, or 10 to 50 mA / W. The perovskite photodetector may have a high responsiveness in the infrared range of the 750 to 2500 nm wavelength range due to the organic coupling between the perovskite thin film and the charge transfer layer.

[0077] According to one embodiment, the perovskite photodetector may include: a substrate; a first electrode stacked on the substrate; the perovskite thin film stacked on the first electrode; the charge transfer layer stacked on the perovskite thin film; and a second electrode stacked on the charge transfer layer.

[0078] According to one embodiment, the first electrode may be a conductive electrode that is ohmic-bonded with the perovskite thin film. As a non-limiting example, the first electrode may be a transparent conductive electrode, and the transparent conductive electrode may be one or more selected from the group consisting of fluorine-doped tin oxide (FTO), indium-doped tin oxide (ITO), zinc oxide, carbon nanotubes, graphene, and combinations thereof, but the present invention is not limited thereto.

[0079] According to one embodiment, the second electrode may be a conductive electrode that is ohmic-junctioned with the perovskite thin film, and it may be acceptable if the work function is different from that of the first electrode so that electrons and holes generated by the photoelectric effect in the perovskite thin film are transferred to the first electrode and the second electrode, respectively, thereby generating a photocurrent. As a non-limiting example, the second electrode may be one or more selected from the group consisting of gold (Au), silver (Ag), platinum (Pt), palladium (Pd), copper (Cu), aluminum (Al), carbon, cobalt sulfide, copper sulfide, nickel oxide, and combinations thereof, but the present invention is not limited thereto.

[0080] According to one embodiment, it is obvious that the performance of the photodetector can be improved by further stacking an electron transport layer or a hole transport layer on top of each component of the perovskite photodetector described above.

[0081] As a non-limiting example, the electron transport layer may be an electron-conducting organic or inorganic material. Specifically, it may be an electron-conducting organic thin film such as 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) or a metal oxide thin film such as titanium oxide, zinc oxide, indium oxide, tin oxide, tungsten oxide, niobium oxide, molybdenum oxide, magnesium oxide, zirconium oxide, strontium oxide, lanthanum oxide, vanadium oxide, aluminum oxide, yttrium oxide, gallium oxide, or a composite thereof, but is not limited thereto, and it is sufficient if it is a material layer commonly used for electron conduction in conventional perovskite photodetectors.

[0082] In addition, as a non-limiting example, the hole transport layer may be a hole-conducting organic or inorganic material. Specifically, it may be a hole-conducting organic thin film such as poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) or copper phthalocyanine (CuPc), or a metal oxide thin film such as tungsten oxide, molybdenum oxide, vanadium oxide, nickel oxide, or a composite thereof, but is not limited thereto, and it is sufficient if it is a material layer commonly used for hole conduction in conventional perovskite photodetectors.

[0083] The present invention provides a method for manufacturing a perovskite photodetector, wherein the method for manufacturing the perovskite photodetector comprises the step of applying a charge transfer layer solution containing one or more organic acceptor molecules having a conjugated structure onto a perovskite thin film; and wherein the band gap of the organic acceptor molecules is 1.3 eV or less.

[0084] In describing the method for manufacturing a perovskite photodetector according to the present invention, since the perovskite photodetector described above may be manufactured by the method for manufacturing a perovskite photodetector, the method for manufacturing a perovskite photodetector according to the present invention includes all the contents described above regarding the perovskite photodetector.

[0085] Examples and experimental examples are described below with specific examples. However, the examples and experimental examples described below are merely illustrative of some aspects, and the technology described in this specification is not limited thereto.

[0087] (Example 1)

[0088] A glass substrate with laminated indium tin oxide (ITO) electrodes was used as the substrate. The substrate was cleaned with acetone and isopropyl alcohol, and the surface was treated for 15 minutes using a UV-ozone surface cleaner.

[0089] A tin oxide electron transport layer was deposited by coating a 70 μl volume of a solution of SnO2 nanoparticles dissolved in non-ionized water at a concentration of 15 wt% onto the surface-treated indium tin oxide electrode using a spin coating method, followed by heat treatment at 100°C for 1 hour.

[0090] A perovskite precursor solution was applied to the above tin oxide electron transport layer using a spin coating method, comprising 1.264 mmol of PbI2 and formamidinium iodide (FAI, Greatsolar) at 1.277 M (TCI), 1.391 mmol of formamidinium iodide (FAI, Greatsolar), 0.063 mmol of methylammonium bromide (MABr, Greatsolar), and lead(II) bromide (PbBr2, Greatsolar) at 0.063 M, 40 mol% of methylammonium chloride (MACI, Sigma Aldrich) dissolved in 0.11 ml of dimethyl sulfoxide and 0.88 ml of dimethylformamide. The spin coating was performed sequentially at 500 rpm for 3 seconds, at 1000 rpm for 5 seconds, and at 5000 rpm for 30 seconds. At this time, 1 ml of dichloroether was dropped onto the rotating substrate 9 seconds after the spin coating began. Subsequently, the substrate on which the spin coating was completed was heat-treated at 100°C for 60 minutes to deposit a perovskite thin film.

[0091] COTIC-4F (acceptor) and PBDTTT-CT (M n =35.4 kDa, PDI=1.16) or PBDTO-TT [M n A charge transfer layer solution was prepared by mixing [=66.3 kDa, PDI=1.33] (donor) in a weight ratio of 1:1.5 and dissolving it in chlorobenzene solvent at a concentration of 22.5 mg / mL.

[0092] The charge transfer layer solution was applied to the perovskite substrate by spin-coating at 550 rpm and dynamic-coating at 2,000 rpm for 30 seconds, and then waited for 30 seconds to complete the stacking of the charge transfer layer.

[0093] A perovskite photodetector was fabricated by depositing an 80 nm gold (Au) electrode on the charge transfer layer using physical vapor deposition (PVD).

[0095] (Example 2)

[0096] In Example 1, a perovskite photodetector was prepared in the same manner as in Example 1, except that PBDTO-TT was used instead of PBDT-TT.

[0098] (Example 3)

[0099] In Example 1, a perovskite photodetector was prepared in the same manner as in Example 1, except that a charge transfer layer solution was prepared by dissolving COTIC-4F in chlorobenzene solvent at a concentration of 10 mg / mL.

[0101] (Comparative Example 1)

[0102] In Example 1, a charge transport layer solution was prepared by mixing spiro-OMeTAD 45.0 mg, 4-tert-butylpyridine (t-BP) 17.55 μl, Li-TFSI (520 mg / ml in ACN) 10.35 μl, FK209 4.5 μl, and ChloroBenzene 495 μl, and a hole transport layer was deposited by spin-coating the hole transport layer solution onto the perovskite thin film at 3,000 rpm for 30 seconds, except that a hole transport layer was deposited. A perovskite photodetector was prepared in the same manner as in Example 1.

[0104] (Experimental Example 1)

[0105] The chemical structures of COTIC-4F (Fig. 1), PBDT-TT (Fig. 2 left), and PBDTO-TT (Fig. 2 right) are shown in Figs. 1 and 2.

[0106] The driving current of the perovskite photodetector according to Example 1 (Fig. 3), Example 2 (Fig. 4), and Example 3 (Fig. 5) is the dark current (left side of Figs. 3 to 5), light of a wavelength of 525 nm (light intensity 17 mW / cm²). 2 )(middle of FIGS. 3 to 5) and light of a wavelength of 940 nm (light intensity 22 mW / cm² 2 Measured under (right side of FIGS. 3 to 5) and illustrated in FIGS. 3 to 5.

[0107] Referring to FIGS. 3 to 5, it was confirmed that the perovskite photodetectors according to Examples 1 to 3 exhibit high detection capability under reverse bias.

[0109] (Experimental Example 2)

[0110] The photoresponse profiles for each bias at a wavelength of 625 nm for the perovskite photodetectors according to Example 1 (Fig. 6), Example 2 (Fig. 7), and Example 3 (Fig. 8) were measured and are shown in FIGS. 6 to 8. Referring to FIGS. 6 to 8, the perovskite photodetectors according to Examples 1 to 3 have a bias of 10 μA / cm² 2 It was confirmed that it exhibits a high photocurrent.

[0111] The photoresponse profiles for each bias at a wavelength of 940 nm for perovskite photodetectors according to Example 1 (Fig. 9), Example 2 (Fig. 10), and Example 3 (Fig. 11) were measured and are shown in Figs. 9 to 11. Referring to Figs. 9 to 11, it was confirmed that the perovskite photodetectors according to Examples 1 to 3 exhibit high photocurrents in long-wavelength light. In addition, the photoresponse profile of the perovskite photodetector according to Comparative Example 1 at a wavelength of 940 nm was measured and is shown in Fig. 12. In particular, referring to Fig. 12, it was confirmed that the device using the conventional hole transport layer Spiro-OMeTAD exhibited a very low response in long-wavelength light, while the perovskite photodetectors according to Examples 1, 2, and 3 exhibited high responses.

[0113] (Experimental Example 3)

[0114] The photoresponse bandwidth of a perovskite photodetector (-1 V bias) for light at a wavelength of 625 nm according to Example 1 (COTIC-4F + PBDT-TT), Example 2 (COTIC-4F + PBDTO-TT), and Example 3 (COTIC-4F) was measured and is shown in Fig. 15.

[0115] The photoresponse bandwidths of the perovskite photodetectors according to Examples 1, 2, and 3 for light at a wavelength of 625 nm were measured to be 200.58 kHz; 442.01 kHz; and 500 kHz or higher, respectively. This is a higher bandwidth than the bandwidth (100 to 150 kHz) of the perovskite photodetector according to Comparative Example 1 (Fig. 13, spiro-OMeTAD), and it is believed that this is because the charge extraction efficiency increased as the charge transfer layer according to the present invention is aligned with the energy level of the perovskite thin film.

[0116] The photoresponse bandwidth of a perovskite photodetector (-1 V bias) for light at a wavelength of 940 nm according to Example 1 (COTIC-4F + PBDT-TT), Example 2 (COTIC-4F + PBDTO-TT), and Example 3 (COTIC-4F) was measured and is shown in Fig. 16.

[0117] The photoresponse bandwidths of the perovskite photodetectors according to Examples 1, 2, and 3 for light at a wavelength of 940 nm were measured to be 24.80 kHz, 33.56 kHz, and 13.35 kHz, respectively.

[0118] The perovskite photodetectors according to Examples 1, 2, and 3 are considered to have secured a sufficient bandwidth for light in the infrared wavelength band. In particular, this value is greater than the photoresponse bandwidth for light at a wavelength of 940 nm of Comparative Example 1 (Fig. 14, spiro-OMeTAD).

[0120] (Experimental Example 4)

[0121] The photoresponse curves of perovskite photodetectors according to Example 1 (Fig. 17), Example 2 (Fig. 18), and Example 3 (Fig. 19) for light at wavelengths of 625 nm (Figs. 17 to 19) and 940 nm (graphs within the boxes of Figs. 17 to 19) were measured and are shown in Figs. 17 to 19.

[0122] Referring to FIGS. 17 to 19, it was confirmed that the perovskite photodetectors according to Example 1, Example 2 and Example 3 have a fast photoresponse speed of 50 μs or less for light of each wavelength.

[0124] (Experimental Example 5)

[0125] The responsivity of perovskite photodetectors according to Example 1 (Fig. 20), Example 2 (Fig. 21), and Example 3 (Fig. 22) is shown in Figs. 20 to 22.

[0126] Referring to FIGS. 20 to 22, the perovskite photodetectors according to Example 1, Example 2 and Example 3 showed a photoresponse of 5 mA / W or more for light of 800 nm or more.

[0128] As described above, the present invention has been explained in this specification by specific details and limited embodiments, but this is provided only to aid in a more comprehensive understanding of the invention, and the invention is not limited to the above embodiments. A person skilled in the art to which the invention pertains can make various modifications and variations from this description. Accordingly, the concept described in this specification should not be 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 themselves, shall be considered to fall within the scope of the concept described in this specification.

Claims

Claim 1 A perovskite photodetector comprising: a perovskite thin film; and a charge transfer layer stacked on the perovskite thin film, wherein the charge transfer layer comprises an organic acceptor having one or more conjugated structures and an organic donor having one or more conjugated structures, wherein the band gap of the organic acceptor is 1.3 eV or less, and the charge transfer layer has a bulk heterojunction structure comprising the organic acceptor and the organic donor. Claim 2 delete Claim 3 delete Claim 4 A perovskite photodetector according to claim 1, wherein the perovskite thin film comprises a perovskite crystal represented by the following chemical formula 1 or chemical formula 2. (Chemical formula 1) ABX3 (Chemical formula 2) A2BX4 (in the above chemical formulas 1 and 2, A is a monovalent alkylammonium cation; a monovalent amidinium cation; Li + ; Na + ; K + ; Rb + ; Cs + ; Fr + ; Cu(I) + ; Ag(I) + and Au(I) + It comprises one or more monovalent cations selected from the group consisting of combinations of, where B is a divalent metal cation, and X is I - , Br - , Cl - Or it is a halogen anion, which is a combination of these.) Claim 5 A perovskite photodetector according to claim 1, wherein the bandgap of the perovskite thin film is 1.3 eV or greater. Claim 6 A perovskite photodetector according to claim 1, having a responsivity to light of any one wavelength in the 750 to 2500 nm wavelength band of 5 mA / W or more. Claim 7 A perovskite photodetector according to claim 1, wherein the organic acceptor is a non-fullerene acceptor (NFA). Claim 8 A perovskite photodetector according to claim 1, wherein the organic acceptor is a non-fullerene acceptor satisfying the following chemical formula 3. (Chemical Formula 3) A-DA'DA (in Chemical Formula 3, A and A' are each the same or different electron withdrawing groups, D is each the same or different electron donating group, and DA'D is an electron-deficient core located at the center of the molecule.) Claim 9 A perovskite photodetector according to claim 1, wherein the organic acceptor comprises one or more chemical species selected from the group comprising COTIC-4F, COTCN2 and derivatives thereof. Claim 10 A method for manufacturing a perovskite photodetector, comprising the step of applying a charge transfer layer solution containing one or more organic acceptor molecules having a conjugated structure and one or more organic donor molecules having a conjugated structure onto a perovskite thin film; wherein the band gap of the organic acceptor molecules is 1.3 eV or less, and the organic acceptor and organic donor are randomly dispersed to form a bulk heterojunction structure. Claim 11 delete Claim 12 A method for manufacturing a perovskite photodetector according to claim 10, wherein the perovskite thin film comprises a perovskite crystal represented by the following chemical formula 1 or chemical formula 2. (Chemical formula 1) ABX3 (Chemical formula 2) A2BX4 (in the above chemical formulas 1 and 2, A is a monovalent alkylammonium-based cation; a monovalent amidinium-based cation; Li + ; Na + ; K + ; Rb + ; Cs + ; Fr + ; Cu(I) + ; Ag(I) + and Au(I) + It comprises one or more monovalent cations selected from the group consisting of combinations of, where B is a divalent metal cation, and X is I - , Br - , Cl - Or it is a halogen anion, which is a combination of these.) Claim 13 A method for manufacturing a perovskite photodetector, wherein, in claim 10, the organic acceptor is a non-fullerene acceptor (NFA). Claim 14 A method for manufacturing a perovskite photodetector according to claim 10, wherein the organic acceptor is a non-fullerene acceptor satisfying the following chemical formula 3. (Chemical Formula 3) A-DA'DA (in Chemical Formula 3, A and A' are each the same or different electron withdrawing groups, D is each the same or different electron donating group, and DA'D is an electron-deficient core located at the center of the molecule.) Claim 15 A method for manufacturing a perovskite photodetector according to claim 10, wherein the organic acceptor comprises one or more chemical species selected from the group including COTIC-4F, COTCN2 and derivatives thereof.

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