Heterojunction compositions, solar cells and photodetectors and methods of making the same

Abstract

The present application relates to the field of solar cells and light detectors, in particular, to a kind of heterojunction composition and solar cell and light detector based on this heterojunction composition and their preparation method.The heterojunction composition contains organic component and inorganic component, wherein, the inorganic component is selected from metal inorganic compound, the organic component is selected from electron acceptor material and optional electron donor material;Metal element in the metal inorganic compound is selected from one or more of Cu, Mo, Zn and W, and non-metal element in the metal inorganic compound is selected from one or more of S, C, N, O and P.The heterojunction composition provided by the present application has weak visible light absorption and higher photoelectric conversion efficiency, and is suitable for being applied in the preparation of solar cell or light detector as photovoltaic material or light detection material.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of solar cells and photodetectors, in particular, to a heterojunction composition, a solar cell and a photodetector and a preparation method thereof. BACKGROUND

[0002] Organic solar cells have the characteristics of solution processing, flexibility and lightness, and are considered as a method to solve the energy crisis. With the semi-transparent characteristics of organic semiconductors, semi-transparent organic solar cells have wide application prospects in smart windows, agricultural greenhouses and floating photovoltaics and have attracted widespread attention. Photoelectric conversion efficiency and average visible light transmittance are two important and contradictory performance indicators of semi-transparent organic solar cells, and balancing the relationship between the two is the main problem of semi-transparent organic solar cells.

[0003] Active layer engineering is an effective method to solve the balance problem between photoelectric conversion efficiency and average visible light transmittance. People have developed strategies such as reducing donor content, adjusting active layer thickness and introducing a third component to improve the overall performance of semi-transparent organic solar cells. The ideal active layer of semi-transparent organic solar cells should have strong absorption capacity in the ultraviolet or near-infrared region, and no absorption in the visible light region. In addition, suitable energy level arrangement between the donor and the acceptor and carrier mobility are also necessary conditions for high-efficiency devices. Due to the rapid development of electron acceptor materials in recent years, the performance of semi-transparent organic solar cells has improved rapidly. However, as far as electron donor materials are concerned, it is difficult to meet the requirements of weak visible light absorption and high mobility within the framework of organic semiconductors.

[0004] Inorganic semiconductors are generally atomic or ionic crystals with regular molecular structures, high mobility, and energy bands determined by the properties and bonding modes of atoms themselves, which can simultaneously achieve weak visible light absorption and high mobility. Therefore, inorganic semiconductors are potential materials for ideal semi-transparent devices. The most common heterojunction composition containing inorganic components is the combination of metal oxide or metal chalcogenide nanoparticle acceptors and polymer donors, but the photoelectric conversion efficiency of such heterojunction composition is very low, so it is necessary to study the heterojunction composition using inorganic electron donor materials, organic electron donor materials and electron acceptor materials. SUMMARY

[0005] The purpose of the present application is to overcome the problems existing in the prior art, and to provide a new heterojunction composition, solar cell and photodetector with weak visible light absorption and high photoelectric conversion efficiency, and a preparation method thereof.

[0006] To achieve the above objectives, the present invention provides a heterojunction composition, characterized in that the composition contains an organic component and an inorganic component, wherein the inorganic component is selected from inorganic metal compounds, and the organic component is selected from electron acceptor materials and optionally electron donor materials;

[0007] The metallic element in the inorganic metal compound is selected from one or more of Cu, Mo, Zn and W, and the non-metallic element in the inorganic metal compound is selected from one or more of S, C, N, O and P;

[0008] The electron donor material is one or more polymers containing repeating structural units as shown in formula (1):

[0009]

[0010] Wherein, the A group is selected from one of the structures shown in formula (1-a), formula (1-b), and formula (1-c):

[0011]

[0012] The electron acceptor material is one or more of the conjugated macromolecules shown in formula (2):

[0013]

[0014] In this structure, the B group and the C group form a conjugated structure;

[0015] Group B is selected from one of the structures shown in formula (2-a), formula (2-b), and formula (2-c):

[0016]

[0017] The C group is selected from 1-3 conjugated structures shown in formula (2-d) or none:

[0018]

[0019] Group D is selected from the group shown in formula (2-e) or is absent:

[0020]

[0021] The E group is selected from the group shown in formula (2-f):

[0022]

[0023] Each of R1, R2, R3, R4, R5, R6, R7, R8 and R9 is independently selected from H, C1-C30 alkyl groups and C1-C30 alkoxy or alkathioyl groups; each of X1, X2, X3, X4, X5, X6, X7, X8 and X9 is independently selected from O, S and Se; each of Y1, Y2 and Y3 is independently selected from H and halogen atoms.

[0024] A second aspect of the present invention provides a photovoltaic material or a photodetector material comprising the above-described heterojunction composition.

[0025] A third aspect of the present invention provides a solar cell comprising the above-described heterojunction composition; wherein the anode modification layer or cathode modification layer of the solar cell contains the inorganic component of the heterojunction composition, and the active layer of the solar cell contains the organic component and optionally the inorganic component of the heterojunction composition.

[0026] A fourth aspect of the present invention provides a method for preparing the above-mentioned solar cell, the method comprising: configuring the heterojunction composition in the solar cell, wherein, depending on the active layer, the structure of the heterojunction can be further divided into a double-layer heterojunction structure, a layer-by-layer heterojunction structure, and a bulk heterojunction structure.

[0027] A fifth aspect of the present invention provides a photodetector comprising a light-trapping active layer, wherein the light-trapping active layer contains the aforementioned heterojunction composition.

[0028] A sixth aspect of the present invention provides a method for preparing the above-described photodetector, wherein the method includes using the heterojunction composition to form an active layer for light trapping.

[0029] This invention provides a heterojunction composition obtained by combining specific metal inorganic compounds with specific organic electron donor and electron acceptor materials. This composition has weak visible light absorption and high photoelectric conversion efficiency, making it very suitable as a photovoltaic material or photodetector material for use in the fabrication of solar cells or photodetectors. Attached Figure Description

[0030] Figure 1 The image shows the IV curve (current-voltage curve) of the solar cell obtained in Example 1.

[0031] Figure 2 The image shows the IV curve of the solar cell obtained in Example 2.

[0032] Figure 3 The image shows the IV curve of the solar cell obtained in Example 3.

[0033] Figure 4The image shows the IV curve of the solar cell obtained in Example 4.

[0034] Figure 5 The image shows the IV curve of the solar cell obtained in Example 5.

[0035] Figure 6 The image shows the IV curve of the solar cell obtained in Example 6.

[0036] Figure 7 The image shows the IV curve of the solar cell obtained in Example 7.

[0037] Figure 8 The image shows the IV curve of the solar cell obtained in Example 8.

[0038] Figure 9 The image shows the IV curve of the solar cell obtained in Example 9.

[0039] Figure 10 The image shows the IV curve of the solar cell obtained in Example 10.

[0040] Figure 11 The visible light transmittance curve is shown for the solar cell obtained in Example 10.

[0041] Figure 12 The image shows the IV curve of the solar cell obtained in Example 11.

[0042] Figure 13 The visible light transmittance curve is shown for the solar cell obtained in Example 11.

[0043] Figure 14 The image shows the IV curve of the solar cell obtained in Example 12.

[0044] Figure 15 The visible light transmittance curve is shown for the solar cell obtained in Example 12.

[0045] Figure 16 The image shows the IV curve of the solar cell obtained in Example 13.

[0046] Figure 17 The visible light transmittance curve is shown for the solar cell obtained in Example 13.

[0047] Figure 18 The image shows the IV curve of the solar cell obtained in Example 14.

[0048] Figure 19 The visible light transmittance curve is shown for the solar cell obtained in Example 14. Detailed Implementation

[0049] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0050] In this invention, each group is independently selected and represented. When each group appears simultaneously and in multiple places in the compound, they are chosen independently and can be the same or different. For example, although... The shown group has 4 R7s, but these 4 R7s can be selected independently; they can be the same or different.

[0051] In this invention, In structures with dashed connecting bonds, the dashed lines indicate the connection points and represent the connecting bonds; Equation (1) In structures with solid connecting bonds, the solid lines outside the brackets that do not connect any groups or atoms also indicate the connection sites, representing connecting bonds.

[0052] In this invention, the C group is selected from 1-3 conjugated structures formed by alternating positive and negative reactions as shown in formula (2-d). The method of connecting these conjugated molecules in an alternating manner is illustrated by example: for instance, when two formulas (2-d) form a conjugated structure, as shown in the structural formula... The two carbon atoms connected by the dashed line share a structure between the two rings. The structure shown; when the three equations (2-d) are connected, as in the structural formula. The carbon atoms connected by the dashed lines share the same structure between the rings. The structure shown.

[0053] In this invention, the compound represented by formula (2) is a conjugated macromolecule, which means that the B group, C group and the compound in formula (2) are conjugated macromolecules. The three are conjugated structures with alternating positive and negative groups. The principle of alternating positive and negative groups is the same as the principle of forming the C group conjugated structure described above. For example, the B group is selected from formula (2-a), the C group is selected from one of formula (2-d), the two ends of the B group are respectively connected to one end of the two C groups, one end of the C group is connected to the B group, and the other end is connected to... Connected, such as in a structural form As shown, the two carbon atoms connected by the dashed line share a structure between the two rings. The structure shown will not be as structural as the formula. The general connection shown is similar to other cases, and will not be explained further here.

[0054] One aspect of the present invention provides a heterojunction composition, wherein the composition contains an organic component and an inorganic component, wherein the inorganic component is selected from metal inorganic compounds, and the organic component is selected from electron acceptor materials and optionally electron donor materials.

[0055] The metallic element in the inorganic metal compound is selected from one or more of Cu, Mo, Zn and W, and the non-metallic element in the inorganic metal compound is selected from one or more of S, C, N, O and P;

[0056] The electron donor material is one or more polymers containing repeating structural units as shown in formula (1):

[0057]

[0058] Wherein, the A group is selected from one of the structures shown in formula (1-a), formula (1-b), and formula (1-c):

[0059]

[0060] The electron acceptor material is one or more of the conjugated macromolecules shown in formula (2):

[0061]

[0062] In this structure, the B group and the C group form a conjugated structure;

[0063] Group B is selected from one of the structures shown in formula (2-a), formula (2-b), and formula (2-c):

[0064]

[0065] The C group is selected from 1-3 conjugated structures shown in formula (2-d) or none:

[0066]

[0067] Group D is selected from the group shown in formula (2-e) or is absent:

[0068]

[0069] The E group is selected from the group shown in formula (2-f):

[0070]

[0071] Each of R1, R2, R3, R4, R5, R6, R7, R8 and R9 is independently selected from H, C1-C30 alkyl groups and C1-C30 alkoxy or alkathioyl groups; each of X1, X2, X3, X4, X5, X6, X7, X8 and X9 is independently selected from O, S and Se; each of Y1, Y2 and Y3 is independently selected from H and halogen atoms.

[0072] The inorganic and organic components in the heterojunction composition can simultaneously achieve weak visible light absorption and high mobility through mutual cooperation. To further enhance the synergistic effect of the heterojunction composition and obtain optoelectronic materials with better photoelectric performance, preferably, the metal inorganic compound is represented by the formula MN, where M is selected from Cu. + Cu 2+ Mo 6+ and Zn 2+ One of them, where N is selected from SCN - O 2- and [P(W3O] 10 )4] 3- One of the following, wherein M and N satisfy chemical valence balance; more preferably selected from CuSCN, Cu(SCN)2, MoO3, ZnO and Cu3[P(W3O] 10 One or more of CuSCN, Cu(SCN)2, CuSCN with MoO3, ZnO and Cu3[P(W3O]2]2; more preferably selected from CuSCN, Cu(SCN)2, CuSCN with MoO3, ZnO and Cu3[P(W3O]2]2. 10 One or more combinations of Cu(SCN)2 and MoO3, ZnO and Cu3[P(W3O)2] 10 )4]2 and one or more combinations thereof. "CuSCN with MoO3, ZnO and Cu3[P(W3O 10 "One or more combinations of )4]2" can include, for example, combinations of CuSCN and MoO3, CuSCN and ZnO, CuSCN and ZnO and Cu3[P(W3O] 10 The combination of Cu(SCN)2 with MoO3, ZnO and Cu3[P(W3O)2]; 10 "One or more combinations of )4]2" can include, for example, a combination of Cu(SCN)2 and MoO3, Cu(SCN)2 and Cu3[P(W3O 10 Combinations of Cu(SCN)2 with MoO3 and ZnO.

[0073] To further enhance the synergistic effect of the heterojunction composition and obtain optoelectronic materials with better photoelectric performance, preferably, each of R1, R2, R3, R4, R5, R6, R7, R8 and R9 is independently selected from H, C1-C20 alkyl groups and C1-C20 alkoxy or alkylthio groups; each of X1, X2, X3, X4, X5, X6, X7, X8 and X9 is independently selected from O, S and Se; and each of Y1, Y2 and Y3 is independently selected from H, F, Cl and Br. More preferably, each of R1, R2, R3, R4, R5, R6, R7, R8, and R9 is independently selected from H, C6-C12 alkyl groups, and C6-C12 alkoxy or alkylthio groups; each of X1, X2, X3, X4, X5, X6, X7, X8, and X9 is independently selected from O, S, and Se; and each of Y1, Y2, and Y3 is independently selected from H, F, and Cl. Even more preferably, each of R1, R2, R3, R4, R5, R6, R7, R8, and R9 is independently selected from H, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, 2-ethylhexyl, 2-n-butyloctyl, n-hexyloxy, 2-ethylhexyloxy, n-nonyloxy, n-undecyloxy, n-hexylthio, n-nonylthio, and n-undecylthio.

[0074] According to the present invention, preferably, the electron donor material is selected from one or more polymers containing repeating structural units shown in formulas (1-1), (1-2), and (1-3):

[0075]

[0076] More preferably, the electron donor material is selected from one or more polymers containing repeating structural units shown in formula (1-1-1), formula (1-2-1), and formula (1-3-1):

[0077]

[0078] Wherein, -C4H9 is n-butyl; -C6H 13 To establish a sound foundation for oneself.

[0079] To improve the performance of the electron donor material, preferably, the polymer containing the repeating structural unit shown in formula (1) has a weight-average molecular weight of 10,000-200,000 g / mol, more preferably 20,000-180,000 g / mol, and even more preferably 30,000-150,000 g / mol, such as 35,000 g / mol, 40,000 g / mol, 50,000 g / mol, 80,000 g / mol, 100,000 g / mol, 120,000 g / mol, 140,000 g / mol and any other value between these values; preferably, the polymer containing the repeating structural unit shown in formula (1) has a PDI (molecular weight distribution coefficient) of 1-5, preferably 1-4, and more preferably 1-3 (for example, it can be 1.2, 1.7, 2.3, 2.7 and any other value between these values).

[0080] When the electron donor material is preferably a polymer containing repeating structural units as shown in formula (1-1), the polymer containing repeating structural units as shown in formula (1-1) more preferably has a weight-average molecular weight of 10,000-80,000 g / mol, more preferably 20,000-60,000 g / mol, and even more preferably 30,000-50,000 g / mol, such as 26,000 g / mol, 38,000 g / mol, 45,000 g / mol, and any value between these values; preferably, the PDI (molecular weight distribution coefficient) of the polymer containing repeating structural units as shown in formula (1-1) is 1-3, preferably 1-2.8, and more preferably 1-2.5 (for example, it can be 1.2, 1.7, 2.1, 2.4, and any value between these values).

[0081] When the electron donor material is preferably a polymer containing repeating structural units as shown in formula (1-2), the polymer containing repeating structural units as shown in formula (1-2) more preferably has a weight-average molecular weight of 20,000-180,000 g / mol, more preferably 40,000-160,000 g / mol, and even more preferably 60,000-140,000 g / mol, such as 65,000 g / mol, 100,000 g / mol, 120,000 g / mol, and any value between these values; preferably, the PDI (molecular weight distribution coefficient) of the polymer containing repeating structural units as shown in formula (1-2) is 1-3, preferably 1-2.8, and more preferably 1-2.5 (for example, it can be 1.2, 1.7, 2.1, 2.4, and any value between these values).

[0082] When the electron donor material is preferably a polymer containing repeating structural units as shown in formula (1-3), the polymer containing repeating structural units as shown in formula (1-3) is more preferably used in this invention with a weight-average molecular weight of 10,000-80,000 g / mol, more preferably 20,000-60,000 g / mol, and even more preferably 30,000-50,000 g / mol, such as 35,000 g / mol, 38,000 g / mol, 46,000 g / mol, and any value between these values; preferably, the PDI (molecular weight distribution coefficient) of the polymer containing repeating structural units as shown in formula (1-3) is 1-3, preferably 1-2.8, and more preferably 1-2.5 (for example, it can be 1.2, 1.7, 2.1, 2.4, and any value between these values).

[0083] According to the present invention, preferably, the electron acceptor material is one or more of the structures shown in formula (2-1), formula (2-2), formula (2-3), formula (2-4), and formula (2-5):

[0084]

[0085]

[0086] More preferably, the electron acceptor material is one or more of the structures shown in formulas (2-1-1), (2-1-2), (2-1-3), and (2-1-4):

[0087]

[0088]

[0089] Wherein, -C4H9 is n-butyl; -C6H 13 For ortho-hexane; -C9H 19 It is a positive base; -C 11 H 23 It is an undecyl group.

[0090] According to the present invention, the proportions of the inorganic and organic components can be adjusted within a wide range. To obtain better photoelectric performance, preferably, the content of the electron acceptor material is 10-400 parts by weight (e.g., 20 parts by weight, 30 parts by weight, 40 parts by weight, 100 parts by weight, 300 parts by weight, etc., and a range selected from any combination of the above numerical ranges) relative to 100 parts by weight of the inorganic component, preferably 20-300 parts by weight, and more preferably 20-50 parts by weight; when the electron donor material is present, the content of the electron donor material is 5-30 parts by weight (e.g., 5 parts by weight, 7 parts by weight, 11 parts by weight, 15 parts by weight, 25 parts by weight, etc., and a range selected from any combination of the above numerical ranges) relative to 100 parts by weight of the inorganic component, preferably 5-20 parts by weight, and more preferably 10-20 parts by weight.

[0091] According to a particularly preferred embodiment of the present invention, in the heterojunction composition, the metal inorganic compound is CuSCN or CuSCN combined with MoO3, ZnO and Cu3[P(W3O] 10 One or more combinations of formula (1-1-1) are used; the electron donor material is of formula (1-1-1). Japanese expression (1-2-1) One or a combination of both; the electron acceptor material is of formula (2-1-1). Equation (2-1-2) Japanese expression (2-1-4) One or more of the following, wherein -C4H9 is n-butyl, -C6H 13 For orthohexyl, -C9H 19 For positive Ren base, -C 11 H 23 It is n-undecyl. In the preferred embodiment described above, more preferably, the content of the electron acceptor material is 20-50 parts by weight relative to 100 parts by weight of the inorganic component; when the electron donor material is present, the content of the electron donor material is 10-20 parts by weight relative to 100 parts by weight of the inorganic component.

[0092] According to the present invention, the polymer composed of repeating structural units shown in formula (1-1-1) is also called PM6; the polymer composed of repeating structural units shown in formula (1-2-1) is also called PTB7-Th; the polymer composed of repeating structural units shown in formula (1-3-1) is also called D18; the compound shown in formula (2-1-1) is also called L8-BO; the compound shown in formula (2-1-2) is also called BTP-eC9; the compound shown in formula (2-1-3) is also called Y6; and the compound shown in formula (2-1-4) is also called BO-4Cl.

[0093] The aforementioned organic compounds may be commercially available products or prepared by conventional methods in the art as disclosed in the literature. For example, PM6 can be prepared by the method provided in the literature "Adv. Mater. 2015, 27, 4655-4660"; PTB7-Th can be prepared by the method provided in the literature "Adv. Mater. 2013, 25, 4766-4771"; D18 can be prepared by the method provided in the literature "Sci. Bull. 2020, 65, 272-275"; L8-BO can be prepared by the method provided in the literature "Nat. Energy 2021, 6, 605"; Y6 can be prepared by the method provided in the literature "Joule 2019, 3, 1140-1151"; BTP-eC9 and BO-4Cl can be prepared by the method provided in the literature "Adv. Mater. 2020, 32, 1908205".

[0094] The heterojunction composition formed by the inorganic and organic components used in this invention exhibits virtually no absorption in the visible light region, with only the organic component showing weak absorption in the visible light region, while exhibiting strong absorption in the ultraviolet region, for example, a strong absorption peak in the wavelength range of 280-320 nm. Its preparation cost is relatively low and it has good thermal stability. Ultraviolet photoelectron spectroscopy results show that the HOMO energy levels of the metal-inorganic compound and the optional electron donor material described in this invention are highly compatible with the electron acceptor material described in this invention. Therefore, the heterojunction composition formed by these components has excellent photoelectric conversion efficiency, making it highly suitable for use as a photovoltaic material or photodetector in solar cells and photodetectors.

[0095] A second aspect of the present invention provides a photovoltaic material or a photodetector material comprising the above-described heterojunction composition.

[0096] A third aspect of the present invention provides a solar cell comprising the heterojunction composition described above. The anode modification layer or cathode modification layer of the solar cell contains the inorganic component of the heterojunction composition, and the active layer of the solar cell contains the organic component and optionally the inorganic component of the heterojunction composition.

[0097] Preferably, the solar cell is a reverse-structure solar cell or a forward-structure solar cell. When the solar cell is a reverse-structure solar cell, the cathode is a transparent electrode having the cathode modification layer thereon, the active layer is disposed on the cathode modification layer, and the anode is composed of the anode modification layer disposed on the active layer and a conductive layer disposed on the anode modification layer. When the solar cell is a forward-structure solar cell, the anode is a transparent electrode having the anode modification layer thereon, the active layer is disposed on the anode modification layer, and the cathode is composed of the cathode modification layer disposed on the active layer and a conductive layer disposed on the cathode modification layer.

[0098] According to the present invention, when the cell is an organic solar cell including a light-trapping active layer, the light-trapping active layer contains the heterojunction composition; when the cell is a semi-transparent solar cell including a light-trapping active layer, the light-trapping active layer contains the heterojunction composition. When the solar cell contains the heterojunction composition of the present invention, the photoelectric conversion efficiency and average visible light transmittance of the active layer can be effectively improved.

[0099] A fourth aspect of the present invention provides a method for preparing the above-mentioned solar cell, the method comprising: configuring the heterojunction composition in the solar cell, wherein, depending on the active layer, the structure of the heterojunction can be further divided into a double-layer heterojunction structure, a layer-by-layer heterojunction structure, and a bulk heterojunction structure.

[0100] Preferably, for the fabrication of organic solar cells, the layer containing photovoltaic material is a light-harvesting active layer or an active layer and a modification layer; for the fabrication of semi-transparent solar cells, the layer containing photovoltaic material is a light-harvesting active layer or an active layer and a modification layer.

[0101] More preferably, the fabrication process of organic solar cells and semi-transparent solar cells may include, for example:

[0102] For a double-layer heterojunction forward device, the inorganic component of the heterojunction composition is coated as the anode modification layer (thickness can be, for example, 10-120 nm) on the conductive glass (which can be cleaned and dried before coating) serving as the anode. Optionally, after drying, the electron acceptor material of the heterojunction composition is coated as the active layer. Optionally, after drying, the cathode interface material is coated as the cathode modification layer (thickness can be, for example, 2-10 nm). Finally, metal (thickness can be, for example, 50-120 nm) is vapor-deposited as the cathode.

[0103] For a layered heterojunction forward device, the inorganic component of the heterojunction composition is coated onto the conductive glass (which can be cleaned and dried before coating) as the anode as the anode modification layer (the thickness can be, for example, 10-120 nm). Optionally, after drying, the electron donor material and the electron acceptor material of the heterojunction composition are coated onto it as the active layer. Optionally, after drying, the cathode interface material is coated onto it as the cathode modification layer (the thickness can be, for example, 2-10 nm). Finally, metal (the thickness can be, for example, 50-120 nm) is vapor-deposited as the cathode.

[0104] For a bulk heterojunction forward device, the inorganic component of the heterojunction composition is coated onto the conductive glass (which can be cleaned and dried before coating) as the anode as the anode modification layer (the thickness can be, for example, 10-120 nm). Optionally, after drying, the inorganic component of the heterojunction composition and the electron acceptor material are coated onto it as the active layer. Optionally, after drying, the cathode interface material is coated onto it as the cathode modification layer (the thickness can be, for example, 2-10 nm). Finally, metal (the thickness can be, for example, 50-120 nm) is vapor-deposited as the cathode.

[0105] For reverse devices, the materials used are the same as those used in the three preparation methods mentioned above, except that the coating sequence is to coat the cathode modification layer, active layer, and anode modification layer on the conductive glass in sequence, and finally evaporate the metal.

[0106] In the fabrication process of the aforementioned organic solar cells and semi-transparent solar cells, the conductive glass can be indium tin oxide (ITO) glass; the cathode interface material can be conventional cathode interface materials in the art such as PDINN and PFNBr; and the metal used as the cathode can be gold, silver, or a combination of both.

[0107] A fifth aspect of the present invention provides a photodetector comprising a light-trapping active layer, wherein the light-trapping active layer contains the aforementioned heterojunction composition.

[0108] A sixth aspect of the present invention provides a method for preparing the above-described photodetector, wherein the method includes using the above-described heterojunction composition to form an active layer for light trapping.

[0109] The present invention will be described in detail below through embodiments.

[0110] In the following examples:

[0111] Using the SS-X50 solar simulator from Guangyan Technology Co., Ltd. and an AM1.5G solar spectral filter, at 100mW / cm²... -2The photovoltaic performance of the device was tested under light intensity. The light intensity was calibrated using a standard polycrystalline silicon solar cell (SRC2020).

[0112] The ultraviolet-visible absorption spectrum and visible light transmission spectrum were measured using a Shimadzu UV-2600i ultraviolet-visible spectrophotometer.

[0113] The IV curve was measured using a Keysight B2901A Source Meter. Parameters such as short-circuit current, open-circuit voltage, fill factor, and photoelectric conversion efficiency can be obtained from the IV curve.

[0114] All materials may be commercially available or prepared by conventional methods in the art as disclosed in the literature. The diethyl sulfide solution of CuSCN was purchased from Sigma-Aldrich, CuSCN from STREM, and diethyl sulfide from Adamas Reagents Ltd. The electron donor materials PM6, PTB7-Th and electron acceptor materials BTP-eC9, Y6, L8-BO, BO-4Cl, and IEICO-4F used in the examples may be commercially available or prepared by conventional methods in the art as disclosed in the literature. PM6 can be prepared by the method provided in the literature "Adv. Mater. 2015, 27, 4655-4660" (weight-average molecular weight 38600 g / mol, PDI = 2); PTB7-Th can be prepared by the method provided in the literature "Adv. Mater. 2013, 25, 4766-4771" (weight-average molecular weight 124000 g / mol, PDI = 1.7); L8-BO can be prepared by the method provided in the literature "Nat. Energy 2021, 6, 605"; Y6 can be prepared by the method provided in the literature "Joule 2019, 3, 1140-1151"; BTP-eC9 and BO-4Cl can be prepared by the method provided in the literature "Adv. Mater. 2020, 32, 1908205"; other materials are not listed here.

[0115] The indium tin oxide (ITO) glass (purchased from Shenzhen Huanan Xiangcheng Technology Co., Ltd.) was first cleaned with detergent, and then ultrasonically cleaned in sequence with deionized water, acetone, and isopropanol. After drying, it was ready for use. The detailed cleaning process will not be described in the following examples.

[0116] Examples 1-9 illustrate the solar cells containing heterojunction compositions of the present invention and their preparation methods; Examples 10-14 illustrate the semi-transparent solar cells containing heterojunction compositions of the present invention and their preparation methods.

[0117] Example 1

[0118] The following embodiments illustrate the bulk heterojunction structure forward device and its fabrication method according to the present invention.

[0119] The indium tin oxide (ITO) glass used as the anode was cleaned and dried. 35 mg of CuSCN was dissolved in 1 mL of diethyl sulfide (DES) to obtain a CuSCN(DES) solution, which was then spin-coated entirely onto the ITO glass. After drying, the anode modification layer (60 nm thick) was obtained. 105 mg of L8-BO was dissolved in 3 mL of chlorobenzene to obtain an L8-BO solution. 0.01 mL of the above CuSCN(DES) solution was mixed thoroughly with 0.03 mL of the above L8-BO solution, and the mixture was spin-coated entirely onto the anode modification layer. After drying, the active layer (70 nm thick) was obtained. PDINN was coated onto the active layer as a cathode modification layer (5 nm thick). Finally, a vacuum (absolute pressure approximately 10) was applied. -5 A 100 nm thick layer of metallic silver was deposited as the cathode of a solar cell.

[0120] The resulting IV curve is as follows Figure 1 As shown. (Through) Figure 1 The open-circuit voltage V of the solar cell can be obtained from the IV curve shown. OC The voltage is 0.769V, and the short-circuit current J is... SC 12.7 mA·cm -2 The fill factor (FF) is 61.3%, and the photoelectric conversion efficiency (PCE) is 6.0%.

[0121] Example 2

[0122] The following embodiments illustrate the layered heterojunction structure forward device and its fabrication method according to the present invention.

[0123] The indium tin oxide (ITO) glass, used as the anode, was cleaned and dried. 35 mg of CuSCN was dissolved in 1 mL of diethyl sulfide (DES) to obtain a CuSCN(DES) solution, which was then spin-coated entirely onto the ITO glass. After drying, an anode modification layer (60 nm thick) was obtained. A solution of 4 mg PM6 dissolved in 1 mL of chloroform and a solution of 10 mg BTP-eC9 dissolved in 1 mL of chloroform were sequentially spin-coated onto the anode modification layer. After drying, an active layer (135 nm thick) was obtained. PDINN was coated onto the active layer as a cathode modification layer (5 nm thick). Finally, a vacuum (absolute pressure approximately 10) was applied. -5 A 100 nm thick layer of metallic silver was deposited as the cathode of a solar cell.

[0124] The resulting IV curve is as follows Figure 2 As shown. (Through) Figure 2 The open-circuit voltage V of the solar cell can be obtained from the IV curve shown. OCThe voltage is 0.866V, and the short-circuit current is J. SC 22.2 mA·cm -2 The fill factor (FF) is 74.3%, and the photoelectric conversion efficiency (PCE) is 14.3%.

[0125] Example 3

[0126] The following embodiments illustrate the double-layer heterojunction structure forward device and its fabrication method according to the present invention.

[0127] The indium tin oxide (ITO) glass, used as the anode, was cleaned and dried. 35 mg of CuSCN was dissolved in 1 mL of diethyl sulfide (DES) to obtain a CuSCN(DES) solution, which was then spin-coated onto the ITO glass. After drying, an anode modification layer (60 nm thick) was obtained. A solution of 15 mg Y6 dissolved in 1 mL of chloroform was spin-coated onto the anode modification layer, and after drying, an active layer (125 nm thick) was obtained. PDINN was coated onto the active layer as a cathode modification layer (5 nm thick), and finally, a vacuum (absolute pressure approximately 10) was applied. -5 A 100 nm thick layer of metallic silver was deposited as the cathode of a solar cell.

[0128] The resulting IV curve is as follows Figure 3 As shown. (Through) Figure 3 The open-circuit voltage V of the solar cell can be obtained from the IV curve shown. OC The voltage is 0.756V, and the short-circuit current J is... SC 9.4 mA·cm -2 The fill factor (FF) is 62.3%, and the photoelectric conversion efficiency (PCE) is 4.4%.

[0129] Example 4

[0130] The following embodiments illustrate the double-layer heterojunction structure forward device and its fabrication method according to the present invention.

[0131] The method described in Example 3 differs in that 10 mg of BTP-eC9 is used instead of Y6 to finally produce a solar cell, which is then tested.

[0132] The resulting IV curve is as follows Figure 4 As shown. (Through) Figure 4 The open-circuit voltage V of the solar cell can be obtained from the IV curve shown. OC The voltage is 0.716V, and the short-circuit current J is... SC 7.0 mA·cm -2 The fill factor (FF) is 55.4%, and the photoelectric conversion efficiency (PCE) is 2.8%.

[0133] Example 5

[0134] The following embodiments illustrate the double-layer heterojunction structure forward device and its fabrication method according to the present invention.

[0135] The method described in Example 3 differs in that 15 mg of L8-BO is used instead of Y6 to finally produce and test a solar cell.

[0136] The resulting IV curve is as follows Figure 5 As shown. (Through) Figure 5 The open-circuit voltage V of the solar cell can be obtained from the IV curve shown. OC The voltage is 0.772V, and the short-circuit current J is... SC 8.1 mA·cm -2 The fill factor (FF) is 46.0%, and the photoelectric conversion efficiency (PCE) is 2.9%.

[0137] Example 6

[0138] The following embodiments illustrate the layered heterojunction structure forward device and its fabrication method according to the present invention.

[0139] The method described in Example 2 differs in that 4 mg of PTB7-Th is used instead of PM6 to finally produce a solar cell, which is then tested.

[0140] The resulting IV curve is as follows Figure 6 As shown. (Through) Figure 6 The open-circuit voltage V of the solar cell can be obtained from the IV curve shown. OC The voltage is 0.708V, and the short-circuit current J is... SC 21.1 mA·cm -2 The fill factor (FF) is 71.0%, and the photoelectric conversion efficiency (PCE) is 10.6%.

[0141] Example 7

[0142] The following embodiments illustrate the double-layer heterojunction structure forward device and its fabrication method according to the present invention.

[0143] The method described in Example 3 differs from that in that 2 mg of Cu3[P(W3O] is used. 10 [4]2 The solution prepared by dissolving in 1 mL of methanol was used to replace the CuSCN (DES) solution. The solution of Y6 was prepared by dissolving 10 mg of IEICO-4F in 1 mL of chlorobenzene solvent. PFNBr was used to replace PDINN. Finally, 100 nm of metallic silver was deposited as the cathode. The solar cell was finally prepared and tested.

[0144] The resulting IV curve is as follows Figure 7 As shown. (Through) Figure 7 The open-circuit voltage V of the solar cell can be obtained from the IV curve shown. OCThe voltage is 0.503V, and the short-circuit current J is... SC 0.3 mA·cm -2 The fill factor (FF) is 30.5%, and the photoelectric conversion efficiency (PCE) is 0.04%.

[0145] Example 8

[0146] The following embodiments illustrate the double-layer heterojunction structure forward device and its fabrication method according to the present invention.

[0147] According to the method described in Example 3, except that a 10nm MoO3 layer was deposited in vacuum instead of the CuSCN layer, and PFNBr was used instead of PDINN to finally obtain a solar cell and test it.

[0148] The resulting IV curve is as follows Figure 8 As shown. (Through) Figure 8 The open-circuit voltage V of the solar cell can be obtained from the IV curve shown. OC The voltage is 0.700V, and the short-circuit current is J. SC 0.6 mA·cm -2 The fill factor (FF) is 29.0%, and the photoelectric conversion efficiency (PCE) is 0.12%.

[0149] Example 9

[0150] The following embodiments illustrate the bilayer heterojunction structure reverse device and its fabrication method according to the present invention.

[0151] The indium tin oxide (ITO) glass, used as the cathode, was cleaned and dried. ZnO was then spin-coated onto the ITO glass using a sol-gel method, and after drying, a cathode modification layer (30 nm thick) was obtained. A solution of 8 mg BTP-eC9 dissolved in 1 mL of chlorobenzene was spin-coated onto the cathode modification layer, and after drying, an active layer (135 nm thick) was obtained. Finally, MoO3 (10 nm thick) was deposited as the anode modification layer using vacuum thermal deposition, while a 100 nm thick layer of metallic silver was vacuum-deposited as the anode of the solar cell. The solar cell was then fabricated and tested.

[0152] The resulting IV curve is as follows Figure 9 As shown. (Through) Figure 9 The open-circuit voltage V of the solar cell can be obtained from the IV curve shown. OC The voltage is 0.642V, and the short-circuit current J is... SC 0.3 mA·cm -2 The fill factor (FF) is 26.5%, and the photoelectric conversion efficiency (PCE) is 0.05%.

[0153] Example 10

[0154] The following embodiments illustrate the bulk heterojunction structure forward device and its fabrication method according to the present invention.

[0155] The method described in Example 1 differs in that the cathode of the device is coated with gold with a thickness of about 2 nm and metallic silver with a thickness of about 10 nm, and a semi-transparent solar cell is finally obtained and tested.

[0156] The resulting IV curve is as follows Figure 10 As shown. (Through) Figure 10 The open-circuit voltage V of the semi-transparent solar cell can be obtained from the IV curve shown. OC The voltage is 0.782V, and the short-circuit current J is... SC 10.1 mA·cm -2 The fill factor (FF) is 58.7%, and the photoelectric conversion efficiency (PCE) is 4.6%.

[0157] The visible light transmittance curve of the device is as follows: Figure 11 As shown, through Figure 11 The transmittance curve shown indicates that the average visible light transmittance of the semi-transparent solar cell is 33.7%.

[0158] Example 11

[0159] The following embodiments illustrate the layered heterojunction structure forward device and its fabrication method according to the present invention.

[0160] The method described in Example 2 differs in that the cathode of the device is coated with gold with a thickness of about 2 nm and metallic silver with a thickness of about 10 nm, and a semi-transparent solar cell is finally obtained and tested.

[0161] The resulting IV curve is as follows Figure 12 As shown. (Through) Figure 12 The open-circuit voltage V of the semi-transparent solar cell can be obtained from the IV curve shown. OC The voltage is 0.846V, and the short-circuit current is J. SC 17.8 mA·cm -2 The fill factor (FF) is 72.0%, and the photoelectric conversion efficiency (PCE) is 10.8%.

[0162] The visible light transmittance curve of the device is as follows: Figure 13 As shown, through Figure 13 The transmittance curve shown indicates that the average visible light transmittance of the semi-transparent solar cell is 30.9%.

[0163] Example 12

[0164] The following embodiments illustrate the layered heterojunction structure forward device and its fabrication method according to the present invention.

[0165] The method described in Example 11 differs in that 8 mg of L8-BO is used instead of BTP-eC9 to finally produce a semi-transparent solar cell, which is then tested.

[0166] The resulting IV curve is as follows Figure 14 As shown. (Through) Figure 14 The open-circuit voltage V of the semi-transparent solar cell can be obtained from the IV curve shown. OC The voltage is 0.890V, and the short-circuit current is J. SC 17.2 mA·cm -2 The fill factor (FF) is 70.4%, and the photoelectric conversion efficiency (PCE) is 10.8%.

[0167] The visible light transmittance curve of the device is as follows: Figure 15 As shown, through Figure 15 The transmittance curve shown indicates that the average visible light transmittance of the semi-transparent solar cell is 30.8%.

[0168] Example 13

[0169] The following embodiments illustrate the layered heterojunction structure forward device and its fabrication method according to the present invention.

[0170] The method described in Example 11 differs in that 8 mg of BO-4Cl is used instead of BTP-eC9 to finally produce a semi-transparent solar cell, which is then tested.

[0171] The resulting IV curve is as follows Figure 16 As shown. (Through) Figure 16 The open-circuit voltage V of the semi-transparent solar cell can be obtained from the IV curve shown. OC The voltage is 0.853V, and the short-circuit current J is... SC 17.9 mA·cm -2 The fill factor (FF) is 70.8%, and the photoelectric conversion efficiency (PCE) is 10.8%.

[0172] The visible light transmittance curve of the device is as follows: Figure 17 As shown, through Figure 17 The transmittance curve shown indicates that the average visible light transmittance of the semi-transparent solar cell is 31.1%.

[0173] Example 14

[0174] The following embodiments illustrate the double-layer heterojunction structure forward device and its fabrication method according to the present invention.

[0175] The method described in Example 4 differs in that the cathode of the device is coated with gold with a thickness of about 2 nm and metallic silver with a thickness of about 10 nm, and a semi-transparent solar cell is finally obtained and tested.

[0176] The resulting IV curve is as follows Figure 18 As shown. (Through) Figure 18 The open-circuit voltage V of the semi-transparent solar cell can be obtained from the IV curve shown. OC The voltage is 0.819V, and the short-circuit current J is... SC 4.8 mA·cm -2 The fill factor (FF) is 47.0%, and the photoelectric conversion efficiency (PCE) is 1.9%.

[0177] The visible light transmittance curve of the device is as follows: Figure 19 As shown, through Figure 19 The transmittance curve shown indicates that the average visible light transmittance of the semi-transparent solar cell is 38.9%.

[0178] Specific data from the above embodiments can be found in Table 1:

[0179] Table 1

[0180]

[0181] As can be seen from the results in Table 1, the solar cells containing the heterojunction composition prepared by the present invention have excellent photoelectric conversion efficiency, with Example 2 reaching as high as 14.3%; the semi-transparent solar cells containing the heterojunction composition prepared by the present invention have excellent photoelectric conversion efficiency and high average visible light transmittance, with Examples 11, 12 and 13 achieving a photoelectric conversion efficiency of 10.8% and an average visible light transmittance of over 30%.

[0182] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A heterojunction composition, characterized in that, The composition contains organic components and inorganic components, wherein the inorganic components are metallic inorganic compounds, and the organic components include electron acceptor materials and electron donor materials; The inorganic metal compound is CuSCN; The electron donor material is selected from one or more polymers containing repeating structural units as shown in formulas (1-1) and (1-2): Equation (1-1) , Equation (1-2) ; The electron acceptor material is one or more of the structures shown in formula (2-1): Equation (2-1) ; Each of R1, R2, R3, R5 and R6 is independently selected from one or more of H and C6-C12 alkyl groups; each of X1, X2, X3, X5, X6 and X8 is S; each of Y1, Y2 and Y3 is independently selected from H and halogen atoms.

2. The heterojunction composition according to claim 1, wherein, Each of R1, R2, R3, R5 and R6 is independently selected from one or more of H, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, 2-ethylhexyl and 2-butyloctyl; each of X1, X2, X3, X5, X6 and X8 is S; each of Y1, Y2 and Y3 is independently selected from one or more of H, F and Cl.

3. The heterojunction composition according to claim 1, wherein, The polymer containing the repeating structural unit shown in formula (1-1) has a weight-average molecular weight of 10,000-80,000 g / mol and a PDI of 1-3; the polymer containing the repeating structural unit shown in formula (1-2) has a weight-average molecular weight of 20,000-180,000 g / mol and a PDI of 1-3.

4. The heterojunction composition according to claim 1, wherein, The electron donor material is selected from one or more polymers containing repeating structural units as shown in formulas (1-1-1) and (1-2-1): Equation (1-1-1) , Equation (1-2-1) ; Among them, -C4H9 is n-butyl.

5. The heterojunction composition according to claim 1, wherein, The electron acceptor material is one or more of the structures shown in formulas (2-1-1), (2-1-2), (2-1-3), and (2-1-4): Equation (2-1-1) , Equation (2-1-2) , Equation (2-1-3) , Equation (2-1-4) ; Wherein, -C4H9 is n-butyl; -C6H 13 For ortho-hexane; -C9H 19 It is a positive base; -C 11 H 23 It is an undecyl group.

6. The heterojunction composition according to claim 1, wherein, The content of the electron acceptor material is 10-400 parts by weight relative to 100 parts by weight of the inorganic component; And / or, relative to 100 parts by weight of the inorganic component, the content of the electron donor material is 5-30 parts by weight.

7. The heterojunction composition according to claim 6, wherein, The content of the electron acceptor material is 20-300 parts by weight relative to 100 parts by weight of the inorganic component; And / or, relative to 100 parts by weight of the inorganic component, the content of the electron donor material is 5-20 parts by weight.

8. A photovoltaic material or photodetector material comprising the heterojunction composition according to any one of claims 1-7.

9. A solar cell comprising the heterojunction composition according to any one of claims 1-7; wherein the anode modification layer or cathode modification layer of the solar cell contains the inorganic component of the heterojunction composition, and the active layer of the solar cell contains the organic component and optionally the inorganic component of the heterojunction composition.

10. The solar cell according to claim 9, wherein, The solar cell is either a reverse-structure solar cell or a forward-structure solar cell. When the solar cell is a reverse-structure solar cell, the cathode is a transparent electrode with the cathode modification layer thereon, the active layer is disposed on the cathode modification layer, and the anode is composed of the anode modification layer disposed on the active layer and a conductive layer disposed on the anode modification layer. When the solar cell is a forward-structure solar cell, the anode is a transparent electrode with the anode modification layer thereon, the active layer is disposed on the anode modification layer, and the cathode is composed of the cathode modification layer disposed on the active layer and a conductive layer disposed on the cathode modification layer.

11. A method for preparing the solar cell of claim 9 or 10, the method comprising: The heterojunction composition according to any one of claims 1-7 is configured in a solar cell, wherein, depending on the active layer, the structure of the heterojunction can be further divided into a double-layer heterojunction structure, a layer-by-layer heterojunction structure, and a bulk heterojunction structure.

12. The method according to claim 11, wherein, For the fabrication of organic solar cells, the layer containing photovoltaic materials is either a light-harvesting active layer or an active layer and a modification layer; for the fabrication of semi-transparent solar cells, the layer containing photovoltaic materials is either a light-harvesting active layer or an active layer and a modification layer.

13. A photodetector comprising a light-trapping active layer, said light-trapping active layer containing the heterojunction composition of any one of claims 1-7.

14. A method for preparing the photodetector of claim 13, the method comprising using the heterojunction composition of any one of claims 1-7 to form a light-trapping active layer.

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