Photoelectric conversion element and method for manufacturing the same

Abstract

The present invention relates to a photoelectric conversion element and a method for manufacturing the same. A photoelectric conversion element and a method for manufacturing the same that can improve characteristics are provided. According to an embodiment, the photoelectric conversion element includes a first conductive layer, a second conductive layer, and a photoelectric conversion layer provided between the first conductive layer and the second conductive layer and containing Sn and Pb. The photoelectric conversion layer includes a first partial region, a second partial region between the first partial region and the second conductive layer, and a third partial region between the second partial region and the second conductive layer. The first partial region has a first Sn concentration and a first Pb concentration. The second partial region has at least one of a second Sn concentration lower than the first Sn concentration and a second Pb concentration higher than the first Pb concentration. The third partial region contains Sn, oxygen, and Pb.

Description

[0001] This application is based on Japanese Patent Application No. 2021-035964 (filing date: March 8, 2021), and claims priority therefrom. This application incorporates the entire contents of that application by reference thereto. Technical Field

[0002] Embodiments of the present invention relate to a photoelectric conversion element and a method for manufacturing the same. Background Art

[0003] For example, for a photoelectric conversion element, improvement of characteristics is pursued. Summary of the Invention

[0004] Embodiments of the present invention provide a photoelectric conversion element capable of improving characteristics and a method for manufacturing the same.

[0005] Means for Solving the Problems

[0006] According to an embodiment of the present invention, a photoelectric conversion element includes a first conductive layer, a second conductive layer, and a photoelectric conversion layer provided between the first conductive layer and the second conductive layer and containing Sn and Pb. The photoelectric conversion layer includes a first partial region, a second partial region between the first partial region and the second conductive layer, and a third partial region between the second partial region and the second conductive layer. The first partial region has a first Sn concentration and a first Pb concentration. The second partial region has at least one of a second Sn concentration lower than the first Sn concentration and a second Pb concentration higher than the first Pb concentration. The third partial region contains Sn, oxygen, and Pb.

[0007] According to the photoelectric conversion element configured as described above, a photoelectric conversion element capable of improving characteristics and a method for manufacturing the same can be provided. Description of the Drawings

[0008] Figure 1 FIG. is a schematic cross-sectional view illustrating a photoelectric conversion element according to a first embodiment.

[0009] Figure 2 FIG. is a transmission electron microscope photograph image illustrating a photoelectric conversion element according to a first embodiment.

[0010] Figure 3 (a) to Figure 3 (c) are graphs illustrating a photoelectric conversion element according to a first embodiment.

[0011] Figure 4 (a) and Figure 4 (b) are graphs illustrating a photoelectric conversion element according to a first embodiment.

[0012] Figure 5 (a) andFigure 5 (b) is a coordinate diagram illustrating the photoelectric conversion element according to the first embodiment.

[0013] Figure 6 Is a coordinate diagram illustrating the photoelectric conversion element according to the first embodiment.

[0014] Figure 7 Is a coordinate diagram illustrating the characteristics of the photoelectric conversion element.

[0015] Figure 8 Is a coordinate diagram illustrating the characteristics of the photoelectric conversion element.

[0016] Figure 9 Is a flowchart illustrating the manufacturing method of the photoelectric conversion element according to the second embodiment.

[0017] Figure 10 Is a schematic side view illustrating the coating device used in the manufacturing method of the photoelectric conversion element according to the second embodiment.

[0018] Figure 11 Is a coordinate diagram illustrating the characteristics related to the manufacturing method of the photoelectric conversion element.

[0019] Explanation of reference numerals

[0020] 10… Photoelectric conversion layer, 10G… Crystal grain, 10a, 10b… First and second surfaces, 11~14… First to fourth partial regions, 21, 22… First and second conductive layers, 25… Substrate, 31, 32… Intermediate layers on the first and second conductive layer sides, 50… Coated object, 55… Coating liquid, 55M… Meniscus, 56… Coating film, 61… Support portion, 62… Coating rod, 63… Coating liquid supply portion, 64… Gas, 65… Gas supply portion, 110… Photoelectric conversion element, 310… Coating device, AR1, AR2… Arrows, Ab1… Absorbance, BE1… Binding energy, C(O), C(Pb), C(Sn)… Concentrations, Int… Intensity, J1… Current density, Pb1, Pb2… First and second Pb concentrations, Rt1… Ratio, Sn1, Sn2… First and second Sn concentrations, V1… Applied voltage, dz… Distance, m / z… Mass-to-charge ratio, pZ… Position, t10~t14, t31, t32… Thicknesses, vg1… Flow rate Detailed embodiments

[0021] Hereinafter, for each embodiment of the present invention, while referring to the attached Figure 1 It will be described.

[0022] The accompanying drawings are schematic or conceptual, and the relationships between the thicknesses and widths of the respective parts, the ratios of the sizes between the parts, etc. do not necessarily have to be the same as in reality. Even when representing the same part, the dimensions and ratios may sometimes be represented differently according to the accompanying drawings.

[0023] In the specification of this application and each of the accompanying drawings, for elements that are the same as those already described in the previous figures, the same reference numerals are assigned and the detailed description is appropriately omitted.

[0024] (First Embodiment)

[0025] Figure 1 is a schematic cross-sectional view illustrating a photoelectric conversion element according to the first embodiment.

[0026] As Figure 1 shown, the photoelectric conversion element 110 according to the embodiment includes a first conductive layer 21, a second conductive layer 22, and a photoelectric conversion layer 10. The photoelectric conversion layer 10 is provided between the first conductive layer 21 and the second conductive layer 22. The photoelectric conversion layer 10 contains Sn and Pb. As will be described later, for example, the photoelectric conversion layer 10 has a perovskite-type crystal structure containing Sn and Pb.

[0027] The photoelectric conversion layer 10 includes a first partial region 11, a second partial region 12, and a third partial region 13. The photoelectric conversion layer 10 may further include a fourth partial region 14. The second partial region 12 is provided between the first partial region 11 and the second conductive layer 22. The third partial region 13 is provided between the second partial region 12 and the second conductive layer 22. The fourth partial region 14 is provided between the first partial region 11 and the second partial region 12. The boundaries between these partial regions may be unclear. These partial regions may be continuous with each other.

[0028] As Figure 1 shown, the photoelectric conversion element 110 may further include an intermediate layer 32 on the second conductive layer side. The intermediate layer 32 on the second conductive layer side is provided between the photoelectric conversion layer 10 and the second conductive layer 22. For example, the third partial region 13 may be in contact with the intermediate layer 32 on the second conductive layer side. The intermediate layer 32 on the second conductive layer side may function as an electron transport layer, for example.

[0029] As Figure 1 shown, the photoelectric conversion element 110 may further include an intermediate layer 31 on the first conductive layer side. The intermediate layer 31 on the first conductive layer side is provided between the first conductive layer 21 and the photoelectric conversion layer 10. For example, the first partial region 11 may be in contact with the intermediate layer 31 on the first conductive layer side. The intermediate layer 31 on the first conductive layer side may function as a hole transport layer, for example.

[0030] As Figure 1As shown, the photoelectric conversion layer 10 may include a first surface 10a and a second surface 10b. There is a second surface 10b between the first surface 10a and the second conductive layer 22. The first surface 10a is the surface on the side of the first conductive layer 21. The second surface 10b is the surface on the side of the second conductive layer 22. The first partial region 11 may include the first surface 10a. The third partial region 13 may include the second surface 10b.

[0031] For example, a substrate 25 may be provided. In one example, the substrate 25 includes, for example, an inorganic material. The substrate 25 may be, for example, a glass substrate or the like. In other examples, the substrate 25 includes an organic material. The substrate 25 includes at least one selected from polyethylene, polyethylene terephthalate, and polyethylene naphthalate. The first conductive layer 21, the photoelectric conversion layer 10, and the second conductive layer 22 are provided on the substrate 25.

[0032] The first direction from the first conductive layer 21 to the second conductive layer 22 is set as the Z-axis direction. One direction perpendicular to the Z-axis direction is set as the X-axis direction. The direction perpendicular to the Z-axis direction and the X-axis direction is set as the Y-axis direction. The first conductive layer 21, the second conductive layer 22, the photoelectric conversion layer 10, the intermediate layer 31 on the first conductive layer side, the intermediate layer 32 on the second conductive layer side, and the substrate 25 extend along the X-Y plane.

[0033] For example, light is incident on the photoelectric conversion layer 10 from one side of one of the first conductive layer 21 and the second conductive layer 22. The light is converted into an electric signal in the photoelectric conversion layer 10.

[0034] Figure 2 is an electron microscope photograph image of the photoelectric conversion element according to the first embodiment.

[0035] Figure 2 is an SEM (Scanning Electron Microscope) image of the photoelectric conversion layer 10. As Figure 2 shown, the photoelectric conversion layer 10 may include a plurality of crystal grains 10G. One of the plurality of crystal grains 10G has a perovskite structure. Each of the plurality of crystal grains 10G has a perovskite structure. The perovskite structure contains Sn and Pb. The structure including the plurality of crystal grains 10G can be formed, for example, by a coating method or the like. The size (for example, the length along one direction) of one of the plurality of crystal grains 10G is, for example, about 100 nm or more and 3 μm or less. It is easy to obtain a large-area photoelectric conversion element.

[0036] In the embodiment, the composition (concentration) of the elements in the photoelectric conversion layer 10 changes along the first direction. Ethylene, an example of the change in the concentration of the elements will be described.

[0037] Figure 3 (a) to Figure 3(c) is a coordinate diagram illustrating the photoelectric conversion element according to the first embodiment.

[0038] The horizontal axis of these diagrams is the position pZ in the Z-axis direction. Figure 3 The vertical axis of (a) is the concentration C(Sn) of Sn. Figure 3 The vertical axis of (b) is the concentration C(Pb) of Pb. Figure 3 The vertical axis of (c) is the concentration C(O) of oxygen. These diagrams are based on the analysis results obtained by XPS (X-ray Photoelectron Spectroscopy). In the specimen, the first conductive layer 21 is ITO (Indium-Tin Oxide). The intermediate layer 31 on the first conductive layer side is an organic film.

[0039] As Figure 3 shown in (a), the concentration C(Sn) of Sn varies along the Z-axis direction. As Figure 3 shown in (b), the concentration C(Pb) of Pb varies along the Z-axis direction. As Figure 3 shown in (c), the concentration C(O) of oxygen is locally high in the third partial region 13.

[0040] As Figure 3 (a) and Figure 3 (b) show that, for example, the first partial region 11 has a first Sn concentration Sn1 and a first Pb concentration Pb1. For example, the second partial region 12 has a second Sn concentration Sn2 and a second Pb concentration Pb2. For example, the second Sn concentration Sn2 is lower than the first Sn concentration Sn1. For example, the second Pb concentration Pb2 is higher than the first Pb concentration Pb1. Thus, the second partial region 12 has at least either the second Sn concentration Sn2 lower than the first Sn concentration Sn1 or the second Pb concentration Pb2 higher than the first Pb concentration Pb1.

[0041] As Figure 3 (a) to Figure 3 (c) show that the third partial region 13 contains Sn, oxygen, and Pb.

[0042] Figure 4 (a) and Figure 4 (b) are coordinate diagrams illustrating the photoelectric conversion element according to the first embodiment.

[0043] These diagrams illustrate the XPS analysis results of the third partial region 13. The horizontal axis of these diagrams is the binding energy BE1. The vertical axis is the intensity Int of the signal (e.g., counts / second).

[0044] As Figure 4As shown in (a), peaks are observed in the range above 494.0 eV and below 497.0 eV. This peak corresponds to the bond between Sn and oxygen. Peaks can also be observed in the range above 485.0 eV and below 488.0 eV. The third partial region 13 contains tin oxide (SnO x ).

[0045] As Figure 4 shown in (b), peaks are observed in the range above 137.5 eV and below 139.0 eV and in the range above 142.5 eV and below 144.0 eV. These peaks correspond to Pb. The peak in the range above 142.5 eV and below 144.0 eV corresponds to the bond between Pb and iodine. The third partial region 13 contains Pb. The third partial region 13 contains lead iodide.

[0046] Figure 5 (a) and Figure 5 (b) are coordinate diagrams of the photoelectric conversion element according to the first embodiment.

[0047] These illustrate the TOF-SIMS (Time-of-Flight Secondary Ion Mass Spectrometry) analysis results of the third partial region 13. The horizontal axis of these diagrams is the mass-to-charge ratio m / z. The vertical axis is the intensity Int of the signal (e.g., count).

[0048] As shown in 5(a), a peak is observed at the position where the mass-to-charge ratio m / z is 152. This peak corresponds to tin oxide (SnO2). A signal can also be observed at the position where the mass-to-charge ratio m / z is 136 (the peak corresponding to SnO). The third partial region 13 contains tin oxide (SnO x ).

[0049] As Figure 5 shown in (b), multiple peaks are observed in the range where the mass-to-charge ratio m / z is above 584 and below 590. These peaks correspond to lead iodide (PbI3). Multiple signals can also be observed in the range where the mass-to-charge ratio m / z is above 457 and below 463 (corresponding to PbI2). Multiple signals can also be observed in the range where the mass-to-charge ratio m / z is above 330 and below 336 (corresponding to PbI).

[0050] Information related to the third partial region 13 can be obtained, for example, by XPS analysis. Information related to the third partial region 13 can be obtained, for example, by TOF-SIMS analysis.

[0051] Thus, the third partial region 13 contains Sn, oxygen, and Pb. It is known that in a photoelectric conversion layer 10 having such a structure, a high conversion efficiency is obtained.

[0052] For example, it is considered that by changing the composition ratio of Sn and Pb, the characteristics of the perovskite compound change. For example, it is considered that by changing the composition ratio of Sn and Pb, at least any one of the band gap, ionization potential, and electron affinity changes. The ionization potential corresponds to the absolute value of the difference between the vacuum energy level and the energy level of the valence band. The electron affinity corresponds to the absolute value of the difference between the vacuum energy level and the energy level of the conduction band. For example, it is considered that as the concentration of Sn becomes higher, the ionization potential and the electron affinity become smaller.

[0053] Due to Figure 3 (a) and Figure 3 the distributions illustrated in (b), for example, it becomes easier to efficiently move the holes generated by photoexcitation to the first conductive layer 21. For example, it is considered that it becomes easier to efficiently move the electrons generated by photoexcitation to the second conductive layer 22. Thereby, the current extraction efficiency is improved. For example, the short-circuit current density is improved. Thereby, the conversion efficiency is improved.

[0054] In the third partial region 13, in addition to the structure containing Pb, tin oxide is also included. Tin oxide can function as an n-type semiconductor. It is considered that since the third partial region 13 contains tin oxide, for example, the electrons generated by photoexcitation become more likely to move to the second conductive layer 22. For example, the short-circuit current density is improved. Thereby, a high conversion efficiency is obtained. According to the embodiment, a photoelectric conversion element capable of improving characteristics can be provided. At least a part of the tin oxide contained in the third partial region 13 can be, for example, amorphous. At least a part of the tin oxide contained in the third partial region 13 can contain, for example, crystals.

[0055] Such a distribution of elements and tin oxide can be formed, for example, by supplying an oxygen-containing gas to the surface when forming the photoelectric conversion layer 10 by coating. As described above, the photoelectric conversion layer 10 includes a plurality of crystal grains 10G. In the third partial region 13, a structure containing oxygen and tin can be formed on the respective surfaces of the plurality of crystal grains 10G. Thereby, for example, it becomes easier to obtain a higher efficiency.

[0056] For example, there is a reference example of a perovskite single-crystal photoelectric conversion layer. In this reference example, it can be considered that after forming the single-crystal photoelectric conversion layer, a tin oxide layer is formed as an electron transport layer. In this case, it is difficult for tin oxide to penetrate into the single-crystal photoelectric conversion layer. Therefore, a region where Pb and tin oxide in the perovskite are detected is not formed.

[0057] The region (the third partial region 13) where tin oxide and Pb are detected is unique to the photoelectric conversion layer 10 including a plurality of crystal grains 10G.

[0058] As Figure 3(As shown in (a), the oxygen-containing region (the third partial region 13) can be locally provided. For example, the first partial region 11 does not contain oxygen. Alternatively, the concentration of oxygen in the first partial region 11 is 1 / 100 or less of the oxygen concentration in the third partial region 13. For example, the second partial region 12 does not contain oxygen. Alternatively, the concentration of oxygen in the second partial region 12 is 1 / 100 or less of the oxygen concentration in the third partial region 13. For example, by the first partial region 11 and the second partial region 12 not containing oxygen, for example, it is easy to maintain a good crystal structure.)

[0059] As Figure 3 (As shown in (c), the thickness t13 of the third partial region 13 along the first direction (Z-axis direction) from the first conductive layer 21 to the second conductive layer 22 is set. The thickness t13 can be thin. The thickness t13 is, for example, 0.1% or more and 5% or less of the thickness t10 of the photoelectric conversion layer 10 along the first direction (refer to Figure 1 ). The thickness t13 of the third partial region 13 is, for example, 1 nm or more and 20 nm or less.)

[0060] The thickness t13 of the third partial region 13 is thinner than the thickness t11 of the first partial region 11 along the first direction (Z-axis direction). The thickness t13 is thinner than the thickness t12 of the second partial region 12 along the first direction (Z-axis direction). As described above, the photoelectric conversion layer 10 may include a fourth partial region 14. The thickness t13 is thinner than the thickness t14 of the fourth partial region 14 along the first direction (Z-axis direction).)

[0061] As Figure 3 (As shown in (a), the rate of change of the concentration C(Sn) of Sn in the fourth partial region 14 with respect to the position change along the first direction (Z-axis direction) is lower than the rate of change of the concentration C(Sn) of Sn in the first partial region 11 with respect to the position change along the first direction (Z-axis direction). The rate of change of the concentration C(Sn) of Sn in the fourth partial region 14 with respect to the position change along the first direction (Z-axis direction) is lower than the rate of change of the concentration C(Sn) of Sn in the second partial region 12 with respect to the position change along the first direction (Z-axis direction).)

[0062] The rate of change of the concentration C(Pb) of Pb in the fourth partial region 14 with respect to the position change along the first direction (Z-axis direction) is lower than the rate of change of the concentration C(Pb) of Pb in the second partial region 12 with respect to the position change along the first direction (Z-axis direction).)

[0063] Figure 6 is a coordinate diagram illustrating the photoelectric conversion element according to the first embodiment.)

[0064] Figure 6 The horizontal axis ofFigure 6 The vertical axis of the graph is the ratio Rt1. The ratio of the average Sn concentration in the photoelectric conversion layer 10 to the average Pb concentration in the photoelectric conversion layer is defined as the average composition ratio Xave. The ratio of the concentration C(Sn) of Sn at the position pZ to the concentration C(Pb) of Pb is defined as the ratio X(pZ). The ratio Rt1 is the ratio of the ratio X(pZ) to the average composition ratio Xave. In this example, the average composition ratio Xave is 0.431.

[0065] As Figure 6 shown, Rt1 in the first partial region 11 is higher than 1. Rt1 in the second partial region 12 is lower than 1.

[0066] In the embodiment, the ratio Rt1 of the concentration of Sn to the concentration of Pb in at least a part of the first partial region 11 is 1.2 times or more the average composition ratio Xave of the average Sn concentration in the photoelectric conversion layer 10 to the average Pb concentration in the photoelectric conversion layer 10.

[0067] The ratio Rt1 of the concentration of Sn to the concentration of Pb in at least a part of the second partial region 12 is 0.8 times or less the average composition ratio Xave of the average Sn concentration in the photoelectric conversion layer 10 to the average Pb concentration in the photoelectric conversion layer 10.

[0068] By setting such a distribution of the composition ratio, it is easy to obtain a high conversion efficiency.

[0069] Figure 7 And Figure 8 is a coordinate graph illustrating the characteristics of the photoelectric conversion element.

[0070] Figure 7 Corresponds to the first sample. Figure 8 Corresponds to the second sample. In the first sample, the photoelectric conversion layer 10 has Figure 3 (a) to Figure 3 (c) The structures exemplified. In the first sample, the photoelectric conversion layer 10 includes the above-described first to fourth partial regions 11 to 14. The third partial region 13 includes Sn, oxygen, and Pb. The third partial region 13 includes tin oxide. The first sample is formed by supplying an oxygen-containing gas to the liquid film after forming the liquid film that becomes the photoelectric conversion layer 10 by coating and then solidifying it.

[0071] In the second sample, the photoelectric conversion layer 10 does not include the third partial region 13 containing Sn, oxygen, and Pb. The second sample is formed by supplying a gas substantially free of oxygen to the liquid film after forming the liquid film that becomes the photoelectric conversion layer 10 by coating and then solidifying it. In the first sample and the second sample, the Sn concentration and the Pb concentration have Figure 3 (a) and Figure 3(b) The distribution illustrated. Figure 7 and Figure 8 For the horizontal axis, the applied voltage is V1. For the vertical axis, the current density is J1.

[0072] Figure 7 In the first sample shown, the conversion efficiency η is 17.8%. The short-circuit current density Isc is 26.8 mA / cm 2 . The open-circuit voltage Voc is 0.87 V. The fill factor FF is 0.76.

[0073] Figure 8 In the second sample shown, the conversion efficiency η is 16.6%. The short-circuit current density Isc is 25.6 mA / cm 2 . The open-circuit voltage Voc is 0.87 V. The fill factor FF is 0.75.

[0074] As can be seen from the comparison between the first sample and the second sample, by providing the third partial region 13 containing Sn, oxygen, and Pb, a high conversion efficiency is obtained.

[0075] In the embodiment, the photoelectric conversion layer 10 contains at least any one of the compound represented by A 1 BX 1 3 and the compound represented by A 2 2A 1 m-1 B m X 1 3m+1 The above “A 1 ” is a monovalent cation containing at least one selected from Cs + , Rb + , K + , Na + , R 1 NH3 + , R 1 2NH2 + and HC(NH2)2 + . The “R 1 ” in “A 1 ” is a monovalent group selected from at least one of hydrogen, a linear alkyl group having 1 or more and 18 or less carbon atoms, a branched alkyl group having 1 or more and 18 or less carbon atoms, a cyclic alkyl group having 1 or more and 18 or less carbon atoms, a substituted aryl group, an unsubstituted aryl group, a substituted heteroaryl group, and an unsubstituted heteroaryl group. The above “A 2 ” contains at least one selected from R 1 NH3 + , R 1 2NH2 + , C(NH2)3 + and R 2 C2H4NH3+ A monovalent cation of at least one of " 2 " in "A 2 " is a monovalent group selected from at least one of a substituted aryl group, an unsubstituted aryl group, a substituted heteroaryl group, and an unsubstituted heteroaryl group. The above-mentioned "B" is a divalent cation containing at least one selected from Pb 2+ and Sn 2+ . The above-mentioned "B" may further contain Ge 2+ . The above-mentioned "X 1 " is a monovalent anion selected from at least one of F - , Cl - , Br - , I - , SCN - and CH3COO - . The above-mentioned "m" is an integer of 1 or more and 20 or less.

[0076] In an embodiment, the photoelectric conversion layer 10 may further contain the following first compound. The first compound contains, for example, at least one selected from pyrrolidone derivatives, urea derivatives, imidazole derivatives, pyridine derivatives, and diamine derivatives. The first compound is, for example, contained in the solution when the photoelectric conversion layer 10 is formed by coating. Due to the first compound, the gaps between the multiple grains 10G of the perovskite-type compound become smaller or substantially disappear, and a dense crystal region is easily obtained. It becomes easy to obtain a high conversion efficiency.

[0077] In an embodiment, the thickness t10 of the photoelectric conversion layer 10 (refer to Figure 1 ) is, for example, 30 nm or more and 1000 nm or less. When the thickness t11 is 30 nm or more, for example, light can be efficiently absorbed, and a high short-circuit current density can be obtained. When the thickness t11 is 1000 nm or less, for example, the carrier transport distance is suppressed from becoming too long. For example, a decrease in conversion efficiency can be suppressed.

[0078] The thickness t31 of the intermediate layer 31 on the first conductive layer side (refer to Figure 1 ) is, for example, 1 nm or more and 200 nm or less. The thickness t32 of the intermediate layer 32 on the second conductive layer side (refer to Figure 1 ) is, for example, 1 nm or more and 200 nm or less. The thickness t11, the thickness t31, and the thickness t32 are lengths along the Z-axis direction.

[0079] The intermediate layer 32 on the second conductive layer side contains at least one selected from, for example, polyaniline, polyaniline derivatives, polythiophene, polythiophene derivatives, polyethylenedioxythiophene: polystyrenesulfonic acid (PEDOT:PSS), polyethyleneimine, polyethyleneimine derivatives, fullerenes, fullerene derivatives, titanium oxide, zinc oxide, molybdenum oxide, tungsten oxide, aluminum oxide, copper oxide, vanadium oxide, nickel oxide, lithium oxide, calcium oxide, cesium oxide, copper iodide, copper thiocyanate, lithium fluoride (LiF), and metallic calcium.

[0080] The intermediate layer 31 on the first conductive layer side contains at least one selected from, for example, polyaniline, polyaniline derivatives, polythiophene, polythiophene derivatives, and polyethylenedioxythiophene: polystyrenesulfonic acid (PEDOT:PSS). The intermediate layer 31 on the first conductive layer side may contain, for example, fullerenes. The intermediate layer 31 on the first conductive layer side may contain at least one selected from, for example, polyethyleneimine, polyethyleneimine derivatives, fullerene derivatives, titanium oxide, zinc oxide, molybdenum oxide, tungsten oxide, aluminum oxide, copper oxide, vanadium oxide, nickel oxide, lithium oxide, calcium oxide, cesium oxide, copper iodide, copper thiocyanate, lithium fluoride (LiF), and metallic calcium.

[0081] The intermediate layer 31 on the first conductive layer side and the intermediate layer 32 on the second conductive layer side can be formed by, for example, at least any one of evaporation coating and printing.

[0082] The first conductive layer 21 contains, for example, a metal oxide. The metal oxide contains, for example, oxygen and at least one selected from indium, zinc, and tin. The first conductive layer 21 may contain at least one selected from, for example, gold, platinum, silver, copper, cobalt, nickel, indium, and aluminum. In one example, the light transmittance of the first conductive layer 21 is higher than that of the second conductive layer 22. The light transmittance can be, for example, the transmittance for visible light.

[0083] The second conductive layer 22 contains at least one selected from, for example, silver, gold, aluminum, copper, titanium, platinum, nickel, tin, zinc, chromium, and lithium. The second conductive layer 22 may contain, for example, a metal oxide. The second conductive layer 22 may contain at least one selected from, for example, conductive polymers, graphene, and carbon nanotubes.

[0084] The substrate 25 can be, for example, light-transmissive. The substrate 25 may contain at least one selected from, for example, resin and glass. The surface of the substrate 25 may contain irregularities. It can enable light from the outside to be incident efficiently.

[0085] (Second Embodiment)

[0086] Figure 9 is a flowchart exemplifying the manufacturing method of the photoelectric conversion element according to the second embodiment.

[0087] Figure 10Schematic side view of a coating apparatus used in the method for manufacturing a photoelectric conversion element according to the second embodiment.

[0088] As Figure 10 shown, the coating apparatus 310 includes, for example, a support portion 61, a coating bar 62, a coating liquid supply portion 63, and a gas supply portion 65. The support portion 61 can support the object to be coated 50. The object to be coated 50 includes, for example, a substrate 25 and a first conductive layer 21. The object to be coated 50 may further include an intermediate layer 31 on the side of the first conductive layer. Coating is performed on the surface of the object to be coated 50. The support portion 61 can be, for example, a stage or the like. In this example, the coating bar 62 is provided above the support portion 61.

[0089] The coating liquid supply portion 63 supplies the coating liquid 55 to at least one of the coating bar 62 and the object to be coated 50. The coating liquid supply portion 63 can form a meniscus 55M containing the coating liquid 55 between the coating bar 62 and the object to be coated 50 to coat the coating liquid 55 on the object to be coated 50. The coating liquid supply portion 63 can include, for example, a syringe or the like.

[0090] For example, the coating bar 62 can move relative to the support portion 61 (i.e., the object to be coated 50) along the arrow AR1. The support portion 61 (i.e., the object to be coated 50) can move relative to the coating bar 62 along the arrow AR2. Along with the movement, the coating liquid 55 of the meniscus 55M is coated on the object to be coated 50. Thus, a coating film 56 based on the coating liquid 55 is formed on the surface of the object to be coated 50.

[0091] The gas supply portion 65 can supply gas 64 to the coating liquid 55 (i.e., the coating film 56) coated on the object to be coated 50. Due to the gas 64, the solvent in the coating film 56 vaporizes and the coating film 56 solidifies. Thereafter, if necessary, heat treatment or the like can also be performed. Thus, a layer based on the coating liquid 55 (for example, the photoelectric conversion layer 10) is obtained.

[0092] As Figure 9 shown, in the method for manufacturing a photoelectric conversion element according to the embodiment, the coating liquid 55 is coated on the object to be coated 50 (step S110). The coating liquid 55 contains a perovskite precursor and a solvent for forming the photoelectric conversion layer 10. The coating liquid 55 preferably contains the above-mentioned first compound. At the time of coating, a meniscus 55M containing such a coating liquid 55 is formed between the coating bar 62 and the object to be coated 50, and the coating liquid 55 is coated on the object to be coated 50.

[0093] In the method for manufacturing a photoelectric conversion element according to the embodiment, gas 64 is supplied to the coating liquid 55 (i.e., the coating film 56) coated on the object to be coated 50 (step S120). The photoelectric conversion layer 10 is formed from the coating liquid 55.

[0094] By supplying an oxygen-containing gas 64 to the coating film 56, a third partial region 13 containing Sn, oxygen, and Pb can be formed.

[0095] In addition to oxygen, the gas 64 contains at least one selected from nitrogen, helium, neon, argon, and air.

[0096] In an embodiment, the flow rate of the gas 64 is, for example, 4 m / s or more. The "flow rate of the gas 64" is defined as the maximum wind speed of the gas 64 supplied to the coating film 56. For example, the maximum wind speed of the gas 64 near the surface of the coating liquid 55 is 4 m / s or more. By using the manufacturing method of the photoelectric conversion element according to the embodiment, the photoelectric conversion layer 10 is formed from the coating liquid 55.

[0097] By using a flow rate of 4 m / s or more, for example, the generation of gaps between multiple crystal regions can be suppressed. For example, a dense photoelectric conversion layer 10 can be easily obtained.

[0098] Figure 11 is a coordinate diagram exemplifying characteristics related to the manufacturing method of the photoelectric conversion element.

[0099] Figure 11 The horizontal axis of is the flow rate vg1 of the gas 64. The vertical axis is the absorbance Ab1 of the photoelectric conversion layer 10 at a wavelength of 700 nm. A high absorbance Ab1 corresponds to small gaps between multiple crystal regions in the photoelectric conversion layer 10. As Figure 11 shown, when the flow rate vg1 is less than 4 m / s, the absorbance Ab1 is low. When the flow rate vg1 is 4 m / s or more, a high absorbance Ab1 is obtained. In an embodiment, for example, the flow rate vg1 is preferably 4 m / s or more, more preferably 6 m / s or more, and further preferably 8 m / s or more. The flow rate vg1 is, for example, 40 m / s or less. The flow rate vg1 is more preferably 30 m / s or less, and further preferably 25 m / s or less. By the flow rate vg1 being 40 m / s or less, for example, the scattering of the coating liquid 55 can be suppressed.

[0100] The boiling point of the solvent is, for example, 200 °C or less. The boiling point can be 165 °C or less. The boiling point can be 140 °C or less. Thereby, for example, the generation of gaps between multiple crystal regions can be suppressed. For example, a dense photoelectric conversion layer 10 can be easily obtained.

[0101] In an embodiment, applying the coating liquid 55 to the coated body 50 includes relatively moving the coated body 50 and the coating bar 62. The relative moving speed is, for example, 20 mm / s or more. By the relative moving speed being 20 mm / s or more, for example, a high productivity is obtained. The relative moving speed can be 200 mm / s or less. Thereby, the excessive supply of the coating liquid 55 onto the coated body 50 is suppressed, and for example, the delay in drying of the solvent can be suppressed. For example, when the relative moving speed exceeds 200 mm / s, the flatness is low and the gaps between the crystal regions are obvious.

[0102] As Figure 10 shown, the supply direction of the gas 64 is along the relative moving direction of the coated body 50. For example, a uniform coating film 56 is easily obtained.

[0103] In an embodiment, the first compound includes, for example, at least one selected from pyrrolidone derivatives, urea derivatives, imidazole derivatives, pyridine derivatives, and diamine derivatives. Thereby, a uniform and stable coating liquid 55 is obtained. For example, in the photoelectric conversion layer 10 formed from the coating liquid 55, a high conversion efficiency is obtained. According to the embodiment, a manufacturing method of a photoelectric conversion element for a photoelectric conversion element capable of improving characteristics can be provided.

[0104] As Figure 10 shown, the distance (for example, the shortest distance) between the support portion 61 and the coating bar 62 is set as the distance dz. The distance dz can be changed according to the relative movement of the coating bar 62 and the coated body 50. For example, the distance dz can be changed at the end portion and the central portion of the coating region. Thereby, the thickness of the coating film 56 can be made more uniform.

[0105] For example, the direction from the support portion 61 toward the coating bar 62 is set as the Za direction. One direction perpendicular to the Za direction is set as the Xa direction. The direction perpendicular to the Za direction and the Xa direction is set as the Ya direction. The distance dz is the length along the Za direction. The relative moving direction (for example, arrow AR1 or arrow AR2) is along the Xa direction.

[0106] In an embodiment, the coating liquid 55 includes, for example, lead iodide (PbI2) (231 mg), tin iodide (SnI2) (186 mg), methylammonium iodide (CH3NH3I: MAI) (152 mg), N-methylpyrrolidone (20 mg), acetone (0.63 mL), and N,N-dimethylformamide (0.42 mL). Lead iodide (PbI2), tin iodide (SnI2), and methylammonium iodide (CH3NH3I: MAI) are examples of perovskite precursors for forming the photoelectric conversion layer 10.

[0107] The optoelectronic conversion element according to the embodiment can be applied to, for example, a solar cell, a light-emitting element, or a light sensor. As the optoelectronic conversion material of the optoelectronic conversion element, a perovskite compound is used, for example. By forming the optoelectronic conversion layer by coating, an optoelectronic conversion layer with a large area can be obtained at low cost, for example. According to the embodiment, a solution of a perovskite compound can be coated in one stage.

[0108] The embodiment may include the following technical solutions.

[0109] (Technical solution 1)

[0110] An optoelectronic conversion element, which includes a first conductive layer, a second conductive layer, and an optoelectronic conversion layer provided between the first conductive layer and the second conductive layer and containing Sn and Pb.

[0111] The optoelectronic conversion layer includes a first partial region, a second partial region between the first partial region and the second conductive layer, and a third partial region between the second partial region and the second conductive layer.

[0112] The first partial region has a first Sn concentration and a first Pb concentration.

[0113] The second partial region has at least one of a second Sn concentration lower than the first Sn concentration and a second Pb concentration higher than the first Pb concentration.

[0114] The third partial region contains Sn, oxygen, and Pb.

[0115] (Technical solution 2)

[0116] The optoelectronic conversion element according to Technical solution 1, wherein the third partial region contains a bond between Sn and oxygen.

[0117] (Technical solution 3)

[0118] The optoelectronic conversion element according to Technical solution 1 or 2, wherein the third partial region contains a bond between Pb and iodine.

[0119] (Technical solution 4)

[0120] The optoelectronic conversion element according to any one of Technical solutions 1 to 3, wherein the optoelectronic conversion layer includes a plurality of crystal grains.

[0121] (Technical solution 5)

[0122] The optoelectronic conversion element according to Technical solution 4, wherein one of the plurality of crystal grains has a perovskite crystal structure.

[0123] (Technical solution 6)

[0124] The photoelectric conversion element according to any one of Technical Solutions 1 to 5, wherein the ratio of the concentration of Sn to the concentration of Pb in at least a part of the above-mentioned first partial region is 1.2 times or more of the average composition ratio of the average Sn concentration in the above-mentioned photoelectric conversion layer to the average Pb concentration in the above-mentioned photoelectric conversion layer.

[0125] (Technical Solution 7)

[0126] The photoelectric conversion element according to any one of Technical Solutions 1 to 5, wherein the ratio of the concentration of Sn to the concentration of Pb in at least a part of the above-mentioned second partial region is 0.8 times or less of the average composition ratio of the average Sn concentration in the above-mentioned photoelectric conversion layer to the average Pb concentration in the above-mentioned photoelectric conversion layer.

[0127] (Technical Solution 8)

[0128] The photoelectric conversion element according to any one of Technical Solutions 1 to 7, wherein the above-mentioned photoelectric conversion layer further includes a fourth partial region between the above-mentioned first partial region and the above-mentioned second partial region,

[0129] The change rate of the concentration of Sn in the above-mentioned fourth partial region with respect to the change in the position in the first direction from the above-mentioned first conductive layer to the above-mentioned second conductive layer is lower than the change rate of the concentration of Sn in the above-mentioned first partial region with respect to the change in the position in the above-mentioned first direction,

[0130] The above-mentioned change rate of the concentration of Sn in the above-mentioned fourth partial region with respect to the change in the position in the above-mentioned first direction is lower than the change rate of the concentration of Sn in the above-mentioned second partial region with respect to the change in the position in the above-mentioned first direction.

[0131] (Technical Solution 9)

[0132] The photoelectric conversion element according to any one of Technical Solutions 1 to 5, wherein the above-mentioned first partial region does not contain oxygen, or the oxygen concentration in the above-mentioned first partial region is 1 / 100 or less of the oxygen concentration in the above-mentioned third partial region,

[0133] The above-mentioned second partial region does not contain oxygen, or the oxygen concentration in the above-mentioned second partial region is 1 / 100 or less of the above-mentioned oxygen concentration in the above-mentioned third partial region.

[0134] (Technical Solution 10)

[0135] The photoelectric conversion element according to any one of Technical Solutions 1 to 9, wherein the thickness of the above-mentioned third partial region along the first direction from the above-mentioned first conductive layer to the above-mentioned second conductive layer is 0.1% or more and 5% or less of the thickness of the above-mentioned photoelectric conversion layer along the above-mentioned first direction.

[0136] (Technical Solution 11)

[0137] The photoelectric conversion element according to any one of Technical Solutions 1 to 9, wherein the thickness of the third partial region along the first direction from the first conductive layer to the second conductive layer is 1 nm or more and 20 nm or less.

[0138] (Technical Solution 12)

[0139] The photoelectric conversion element according to any one of Technical Solutions 1 to 9, wherein the thickness of the third partial region along the first direction from the first conductive layer to the second conductive layer is thinner than the thickness of the first partial region along the first direction and thinner than the thickness of the second partial region along the first direction.

[0140] (Technical Solution 13)

[0141] The photoelectric conversion element according to any one of Technical Solutions 1 to 12, further comprising an intermediate layer on the second conductive layer side provided between the photoelectric conversion layer and the second conductive layer,

[0142] The third partial region is in contact with the intermediate layer on the second conductive layer side.

[0143] (Technical Solution 14)

[0144] The photoelectric conversion element according to Technical Solution 13, wherein the intermediate layer on the second conductive layer side contains at least one selected from the group consisting of polyaniline, polyaniline derivatives, polythiophene, polythiophene derivatives, polyethylenedioxythiophene: polystyrenesulfonic acid (PEDOT:PSS), polyethyleneimine, polyethyleneimine derivatives, fullerenes, fullerene derivatives, titanium oxide, zinc oxide, molybdenum oxide, tungsten oxide, aluminum oxide, copper oxide, vanadium oxide, nickel oxide, lithium oxide, calcium oxide, cesium oxide, copper iodide, copper thiocyanate, lithium fluoride (LiF), and metallic calcium.

[0145] (Technical Solution 15)

[0146] The photoelectric conversion element according to any one of Technical Solutions 1 to 14, wherein the photoelectric conversion layer contains at least any one of the compound represented by A 1 BX 1 3 and the compound represented by A 2 2A 1 m-1 B m X 1 3m+1 1

[0147] The above A 1 is selected from the group consisting of Cs + 、Rb + 、K+ , Na + , R 1 NH3 + , R 1 2NH2 + and HC(NH2)2 + and at least one monovalent cation selected from the group consisting of

[0148] The above-mentioned A 1 The above-mentioned R in 1 is a monovalent group selected from at least one of hydrogen, linear alkyl groups having 1 to 18 carbon atoms, branched alkyl groups having 1 to 18 carbon atoms, cyclic alkyl groups having 1 to 18 carbon atoms, substituted aryl groups, unsubstituted aryl groups, substituted heteroaryl groups, and unsubstituted heteroaryl groups.

[0149] The above-mentioned A 2 contains a monovalent cation selected from at least one of 1 NH3 + , R 1 2NH2 + , C(NH2)3 + and R 2 C2H4NH3 + and at least one monovalent cation selected from the group consisting of

[0150] The above-mentioned A 2 The above-mentioned R in 2 is a monovalent group selected from at least one of substituted aryl groups, unsubstituted aryl groups, substituted heteroaryl groups, and unsubstituted heteroaryl groups.

[0151] The above-mentioned B contains a divalent cation selected from at least one of 2+ Pb 2+ and Sn

[0152] The above-mentioned X 1 is a monovalent anion selected from at least one of - F - Cl - Br - I - SCN - and CH3COO

[0153] The above-mentioned m is an integer of 1 or more and 20 or less.

[0154] (Technical Solution 16)

[0155] A method for manufacturing a photoelectric conversion element, wherein a meniscus containing a coating liquid is formed between a coating rod and a coated body to coat the coating liquid on the coated body, and the coating liquid contains a perovskite precursor and a solvent for forming a photoelectric conversion layer;

[0156] Supply an oxygen-containing gas to the coating liquid coated on the coated body;

[0157] Form a photoelectric conversion layer from the coating liquid.

[0158] (Technical solution 17)

[0159] The method for manufacturing a photoelectric conversion element according to Technical solution 16, wherein the gas contains at least one selected from nitrogen, helium, neon, argon, and air.

[0160] (Technical solution 18)

[0161] The method for manufacturing a photoelectric conversion element according to Technical solution 16 or 17, wherein the boiling point of the solvent is 200°C or lower.

[0162] (Technical solution 19)

[0163] The method for manufacturing a photoelectric conversion element according to any one of Technical solutions 16 to 18, wherein coating the coating liquid on the coated body includes moving the coated body relative to the coating rod,

[0164] The speed of the relative movement is 20 mm / s or more.

[0165] (Technical solution 20)

[0166] The method for manufacturing a photoelectric conversion element according to any one of Technical solutions 16 to 19, wherein the supply direction of the gas is along the relative movement direction of the coated body.

[0167] According to the embodiment, a photoelectric conversion element capable of improving characteristics and a manufacturing method thereof can be provided.

[0168] Above, the embodiments of the present invention have been described while referring to specific examples. However, the present invention is not limited to these specific examples. For example, regarding the specific configurations of each element such as the conductive layer and the photoelectric conversion layer included in the photoelectric conversion element, as long as those skilled in the art can appropriately select from the publicly known range and can implement the present invention in the same way and obtain the same effects, they are included in the scope of the present invention.

[0169] In addition, a configuration obtained by combining any two or more elements of each specific example within the technically possible range, as long as it includes the gist of the present invention, is also included in the scope of the present invention.

[0170] In addition, all of the photoelectric conversion elements, coating liquids, coating methods, and coating apparatuses that can be appropriately designed and modified by those skilled in the art based on the photoelectric conversion elements, coating liquids, coating methods, and coating apparatuses described as embodiments of the present invention also belong to the scope of the present invention as long as they include the gist of the present invention.

[0171] In addition, within the scope of the idea of the present invention, various modifications and corrections that can be conceived by those skilled in the art are understood to also belong to the scope of the present invention.

[0172] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the present invention. These novel embodiments can be implemented in various other ways, and various omissions, substitutions, and changes can be made without departing from the gist of the present invention. These embodiments or their modifications are included in the scope and gist of the present invention, and are included in the invention described in the claims and its equivalents.

Claims

1. A photoelectric conversion element comprising a first conductive layer, a second conductive layer, and a photoelectric conversion layer provided between the first conductive layer and the second conductive layer and containing Sn and Pb. The photoelectric conversion layer includes a first partial region, a second partial region between the first partial region and the second conductive layer, and a third partial region between the second partial region and the second conductive layer. The first partial region has a first Sn concentration and a first Pb concentration. The second partial region has at least one of a second Sn concentration lower than the first Sn concentration and a second Pb concentration higher than the first Pb concentration. The third partial region contains Sn, oxygen, and Pb. The photoelectric conversion layer includes a plurality of crystal grains.

2. The optoelectronic conversion element according to claim 1, wherein, The third partial region contains a bond between Sn and oxygen.

3. The photoelectric conversion element according to claim 1, wherein, The third partial region contains a bond between Pb and iodine.

4. The photoelectric conversion element according to claim 1, wherein, One of the plurality of crystal grains has a perovskite crystal structure.

5. The photoelectric conversion element according to claim 1, wherein, The first partial region does not contain oxygen, or the oxygen concentration in the first partial region is 1 / 100 or less of the oxygen concentration in the third partial region. The second partial region does not contain oxygen, or the oxygen concentration in the second partial region is 1 / 100 or less of the oxygen concentration in the third partial region.

6. The photoelectric conversion element according to claim 1, further comprising a second conductive layer side intermediate layer provided between the photoelectric conversion layer and the second conductive layer. The third partial region is in contact with the second conductive layer side intermediate layer.

7. The photoelectric conversion element according to claim 1, wherein, The above-mentioned optoelectronic conversion layer contains a compound represented by A 1 BX 1 3 and at least any one of the compounds represented by A 2 2A 1 m-1 B m X 1 3m+1 indicated. The above-mentioned A 1 is a monovalent cation containing at least one selected from Cs + , Rb + , K + , Na + , R 1 NH3 + , R 1 2NH2 + and HC(NH2)2 + . The above-mentioned A 1 The above-mentioned R in 1 is a monovalent group selected from at least one of hydrogen, a linear alkyl group having 1 or more and 18 or less carbon atoms, a branched alkyl group having 1 or more and 18 or less carbon atoms, a cyclic alkyl group having 1 or more and 18 or less carbon atoms, a substituted aryl group, an unsubstituted aryl group, a substituted heteroaryl group, and an unsubstituted heteroaryl group. The above A 2 is a monovalent cation containing at least one selected from R 1 NH3 + , R 1 2NH2 + , C(NH2)3 + and R 2 C2H4NH3 + . The above-mentioned A 2 The above-mentioned R in 2 is a monovalent group selected from at least one of a substituted aryl group, an unsubstituted aryl group, a substituted heteroaryl group, and an unsubstituted heteroaryl group. B above is a divalent cation containing at least one selected from Pb 2+ and Sn 2+ in it, The above-mentioned X 1 is a monovalent anion selected from at least one of F - , Cl - , Br - , I - , SCN - and CH3COO - . The m is an integer of 1 or more and 20 or less.

8. The manufacturing method of the photoelectric conversion element according to any one of claims 1 to 7, wherein, A meniscus containing a coating liquid is formed between a coating rod and a coated body to coat the coating liquid on the coated body, and the coating liquid contains a perovskite precursor and a solvent for forming a photoelectric conversion layer. An oxygen-containing gas is supplied to the coating liquid coated on the coated body. A photoelectric conversion layer is formed from the coating liquid.

9. The manufacturing method of the photoelectric conversion element according to claim 8, wherein, The gas contains at least one selected from nitrogen, helium, neon, argon, and air.

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