Fused Aromatic Hydrocarbon Carboxylic Acid Derivatives and Their Applications in Perovskite-Based Solar Cells

Abstract

The present invention provides a polycyclic aromatic hydrocarbon carboxylic acid derivative and its application in a perovskite-based solar cell. Using a polycyclic aromatic hydrocarbon moiety with a rigid large π-conjugated plane as the parent nucleus and an alkyl carboxylic acid as a chemical anchoring group can effectively increase the overlap of π-orbitals between adjacent molecules, enhance the migration ability of its delocalized π electrons. The polycyclic aromatic hydrocarbon without heteroatoms ensures that its planar structure is not affected, thus being more conducive to the formation of a face-to-face conjugate structure between adjacent molecules, enabling selective and stable bonding of the self-assembled hole-selective material on the surface of the conductive oxide, and simultaneously achieving energy level matching between the upper and lower transport layers, promoting efficient carrier transport. When used as a self-assembled hole-selective material in a perovskite-based solar cell, it promotes charge transport and improves the photoelectric conversion efficiency of the perovskite-based device.

Description

Technical Field

[0001] The present invention relates to the field of perovskite-based solar cells, and particularly to a polycyclic aromatic hydrocarbon carboxylic acid derivative and its application in perovskite-based solar cells. Background Art

[0002] Developing photovoltaic technologies for efficient utilization of solar energy resources is widely regarded as an effective measure to solve the energy crisis and ecological environment, and is also a long-term plan of our country in the field of energy security. As the third-generation new solar cells, perovskite-based solar cells have significant advantages such as low cost, high light absorption coefficient, and long carrier lifetime compared with traditional photovoltaic technologies, and have received widespread attention. In particular, inverted perovskite solar cells have lower water and oxygen sensitivity and better structural compatibility in tandem cells, and are expected to be commercialized first in the future. However, due to the lack of efficient hole transport materials, it has been difficult to improve the power conversion efficiency of inverted perovskite solar cells. The strategy to solve this key problem is to find alternative efficient hole-selective materials to reduce the energy loss at the device interface.

[0003] An ideal hole-selective contact layer can not only promote the crystallization and growth of the perovskite light-absorbing layer, but also block the electron transport and achieve efficient hole extraction. The hole-selective contact layer formed by self-assembly of small molecules has significant advantages such as simple synthesis, low cost, high stability, high material utilization rate, and high hole extraction rate. However, the currently commercialized self-assembled small molecule hole-selective materials are mainly carbazole-based phosphonic acid derivatives, and the Chinese patent document with the publication number CN114512613A also discloses the use of 7-butylphosphonic acid-7H-dibenzo[c,g]carbazole self-assembled small molecules as the hole-selective material for inverted perovskite solar cells. However, due to the influence of the π structure, the hole transport performance of carbazole-based phosphonic acid derivatives is low. Therefore, exploring new self-assembled small molecule hole-selective materials has become a hot issue in the research field of photovoltaic perovskites. Summary of the Invention

[0004] The purpose of the present invention is to provide a polycyclic aromatic hydrocarbon carboxylic acid derivative and its application in perovskite-based solar cells. Using the polycyclic aromatic hydrocarbon carboxylic acid derivative as the hole-selective contact layer of the perovskite-based solar cell has the advantages of high hole mobility, good thermal stability, and low cost, and can be used as an efficient and stable self-assembled hole-selective material in inverted perovskite solar cells.

[0005] Polycyclic aromatic hydrocarbons (PAHs) refer to organic compounds formed by the fusion of several benzene rings, such as naphthalene, anthracene, pyrene, pentacene, and perylene. This structure has a large π-conjugated rigid planar group and excellent charge migration ability. At the same time, the strong intermolecular forces increase the degree of overlap of π-orbitals between adjacent PAH molecules and are expected to further enhance the carrier migration rate. In addition, the planar rigid structure of the polycyclic group makes these compounds have good thermal stability, which helps to improve the overall stability of the device structure. When PAHs further use alkyl carboxylic acid as an anchoring group, stable bonding of the self-assembled hole-selective material on the surface of the oxide substrate can be achieved. Based on the above mechanism, this solution provides a PAH carboxylic acid derivative that can be used as a hole-selective contact layer for perovskite-based solar cells. This PAH carboxylic acid derivative uses a polycyclic aromatic hydrocarbon unit with a rigid large π-conjugated plane as the mother nucleus (without other heteroaromatic ring structures) and an alkyl carboxylic acid as a chemical anchoring group, and is effectively fixed with -In-O- and -Sn-O- on the ITO surface.

[0006] In the first aspect, the PAH carboxylic acid derivative provided by this solution uses a polycyclic aromatic hydrocarbon unit with a rigid large π-conjugated plane as the mother nucleus and an alkyl carboxylic acid as a chemical anchoring group, and its structural formula is shown in formula (I):

[0007]

[0008] Among them, the polycyclic aromatic hydrocarbon unit does not contain other heteroatoms and is selected from any one of the following structural formulas:

[0009]

[0010] In some embodiments, n in the structural formula (I) is an integer from 1 to 10.

[0011] In some embodiments, the R group is selected from any one of the following groups: independently selected from hydrogen, linear alkyl, linear alkenyl, linear alkynyl, alkoxy, cyclic alkyl, and heteroaryl with or without substituents.

[0012] In some embodiments, the linear alkyl and cyclic alkyl are selected as C1-C40 alkyl. If the R group is a linear alkyl, the linear alkyl is one of methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, octadecyl, eicosyl, tricosyl, or tetracosyl. If the R group is a cyclic alkyl, the cyclic alkyl is one of cyclopentyl, cyclohexyl, or cyclooctyl with or without substituents.

[0013] In some embodiments, the chain alkenyl and cyclic alkenyl are selected as C2-C40 alkenyl. If the R group is a chain alkenyl, the chain alkenyl is one of vinyl, propenyl, butadienyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, dodecenyl, tetradecenyl, hexadecenyl or heptadecenyl; if the R group is a cyclic alkenyl, the cyclic alkenyl is one of cyclopentenyl, cyclooctenyl, cycloheptatrienyl, cyclooctatetraenyl or cyclododecenyl.

[0014] In some embodiments, the chain alkynyl is selected as C3-C40 alkynyl. If the R group is a chain alkynyl, the chain alkynyl is one of propynyl, butadiynyl, pentynyl, hexynyl, heptynyl, octynyl, nonynyl, decynyl, undecynyl, tridecynyl, tetradecynyl, pentadecynyl or hexadecynyl.

[0015] In some embodiments, the chain alkoxy and cyclic alkoxy are selected as C1-C40 alkoxy. If the R group is a chain alkoxy, the chain alkoxy is one of C1-C16 chain alkoxies; if the R group is a cyclic alkoxy, the cyclic alkoxy is one of glycidyl, cyclohexyl oxide, cyclopentyl oxide, dioxolanyl or dioxanyl.

[0016] In some embodiments, the substituents in the R group are one of methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, methoxy, ethoxy, propoxy, methylthio, ethylthio, propylthio, hydroxyl, carboxyl, mercapto, fluorine atom, chlorine atom, bromine atom, iodine atom, methylamino or aldehyde group.

[0017] Preferably, the polycyclic aromatic hydrocarbon carboxylic acid derivative is NaPA, AnPA, JR0, PTPA or JR1, and the structural formula is shown as follows:

[0018]

[0019] The design concept of the polycyclic aromatic hydrocarbon carboxylic acid derivative in the present invention is to use a polycyclic aromatic hydrocarbon moiety with a large π-conjugated rigid plane as the parent nucleus and an alkyl carboxylic acid as the chemical anchoring group. The delocalized π electrons in the planar polycyclic aromatic hydrocarbons such as naphthalene, anthracene and pyrene are more conducive to the formation of face-to-face π-π conjugate structures between molecules, enhancing the π electron migration ability between molecules; the strong intermolecular force of the planar structure improves the molecular packing stability, so that such compounds have good thermal stability; at the same time, using an alkyl carboxylic acid as the chemical anchoring group can achieve selective and stable bonding of the polycyclic aromatic hydrocarbon carboxylic acid derivative on the surface of the conductive oxide; the introduction of the R group is used to adjust the charge density of the polycyclic aromatic hydrocarbon parent nucleus, thereby adjusting the energy band structure of the polycyclic aromatic hydrocarbon carboxylic acid derivative, so as to have a better energy level matching with the substrate and the perovskite light-absorbing layer.

[0020] In a second aspect, the present solution provides an application of a polycyclic aromatic hydrocarbon carboxylic acid derivative in a perovskite-based solar cell, using the polycyclic aromatic hydrocarbon carboxylic acid derivative as a self-assembled hole-selective material for the perovskite-based solar cell.

[0021] In some embodiments, the structure of the perovskite-based solar cell includes a transparent conductive substrate, a hole-selective contact layer, a perovskite light-absorbing layer, an electron transport layer, a modification layer, and a top electrode, and the hole-selective contact layer is prepared from the polycyclic aromatic hydrocarbon carboxylic acid derivative.

[0022] In some embodiments, the transparent conductive substrate includes, but is not limited to, ITO, FTO, AZO, IZO, graphene conductive substrate, Ag nanowire conductive substrate, Cu nanowire conductive substrate, Si, or CIGS, etc.

[0023] In some embodiments, the self-assembled hole-selective contact layer can be prepared from the polycyclic aromatic hydrocarbon carboxylic acid derivative by methods such as soaking, spin coating, dip coating, LB film deposition, or evaporation.

[0024] In some embodiments, the perovskite light-absorbing layer can be prepared from lead-based perovskite, tin-based perovskite, or tin-lead perovskite, etc. by methods such as spin coating, dip coating, slot die coating, screen printing, spraying, inkjet printing, roll-to-roll process, or evaporation.

[0025] In some embodiments, the electron transport layer can be prepared from C 60 、C 70 、PC 61 BM、PC 71 BM、TiO2, ZnO, or SnO2, etc. by methods such as spin coating, dip coating, evaporation, atomic layer deposition, or magnetron sputtering.

[0026] In some embodiments, the top electrode includes, but is not limited to, Ag, Cu, Au, Al, Cr, ITO, IZO, FTO, AZO, or C electrode, etc., and can be prepared by methods such as dip coating, slot die coating, screen printing, thermal evaporation, atomic layer deposition, or magnetron sputtering.

[0027] In some embodiments, the perovskite-based solar cell can be fabricated into a single-sided or double-sided device.

[0028] In some embodiments, the perovskite-based solar cell can be used as one of the sub-cells of a single-junction device or a four-terminal silicon / perovskite tandem solar cell, CIGS / perovskite tandem solar cell, or organic / perovskite tandem solar cell.

[0029] Compared with the prior art, the present technical solution has the following characteristics and beneficial effects:

[0030] (1) A polycyclic aromatic hydrocarbon carboxylic acid derivative is designed with a polycyclic aromatic hydrocarbon unit having a large π-conjugated rigid plane as the parent nucleus and an alkyl carboxylic acid as the chemical anchoring group. The polycyclic aromatic hydrocarbon molecule with a planar structure can effectively increase the overlap of π-orbitals between adjacent molecules, enhance the migration ability of its delocalized π-electrons, and thus is beneficial to improving the carrier transport kinetics when used as a hole transport layer. The charge delocalization degree within the polycyclic aromatic hydrocarbon parent nucleus molecule is high; the strong intermolecular force improves the molecular packing stability, so that such compounds have good thermal stability. In other words, the polycyclic aromatic hydrocarbon without heteroatoms ensures that its planar structure is not affected, so it is more conducive to the formation of a face-to-face conjugated structure between adjacent molecules, ensuring that the molecular structure rigidity is not affected, making it have good thermal stability as a hole transport layer. At the same time, with an alkyl carboxylic acid as the chemical anchoring group, it can achieve selective stable bonding of the polycyclic aromatic hydrocarbon carboxylic acid derivative on the surface of the conductive oxide, and at the same time achieve energy level matching between the upper and lower transport layers, promoting the efficient transport of carriers. The introduction of the R group is used to adjust the charge density of the polycyclic aromatic hydrocarbon parent nucleus, thereby adjusting the energy band structure of the polycyclic aromatic hydrocarbon carboxylic acid derivative, so as to have better energy level matching with the substrate and the perovskite light-absorbing layer.

[0031] (2) Using the polycyclic aromatic hydrocarbon carboxylic acid derivative as a self-assembled hole-selective material to prepare a perovskite-based solar cell, a photoelectric conversion efficiency of >15% can be obtained. The polycyclic aromatic hydrocarbon carboxylic acid derivative promotes charge transport, reduces the overall series resistance of the device, and improves the photoelectric conversion efficiency of the perovskite-based device. Brief Description of the Drawings

[0032] Figure 1 It is a schematic diagram of the structure of an inverted perovskite solar cell.

[0033] Figure 2 It is the XPS of naphthylpropyl carboxylic acid (NaPA), anthracenylpropyl carboxylic acid (AnPA), and pyrenylpropyl carboxylic acid (JR1) chemically adsorbed on the ITO surface.

[0034] Figure 3 It is the J-V curve of the perovskite-based solar cell based on naphthylpropyl carboxylic acid (NaPA) in Application Example 1.

[0035] Figure 4 It is the J-V curve of the perovskite-based solar cell based on anthracenylpropyl carboxylic acid (AnPA) in Application Example 2.

[0036] Figure 5 It is the J-V curve of the perovskite-based solar cell based on pyrenylpropyl carboxylic acid (JR1) in Application Example 3.

[0037] Figure 6 It is the J-V curve of the perovskite-based solar cell based on pyrenylpropyl carboxylic acid (JR0) in Application Example 4.

[0038] Figure 7 This is the JV curve of the perovskite-based solar cell based on anthracenepropylcarboxylic acid (PTPA) in Application Example 5. DETAILED DESCRIPTION

[0039] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0040] Those skilled in the art should understand that, in the disclosure of the present invention, the orientation or position relationship indicated by the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. are based on the orientation or position relationship shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the above terms should not be understood as limiting the present invention.

[0041] It is to be understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the element may be multiple, and the term "one" should not be understood as a limitation on the quantity.

[0042] Application Example 1:

[0043] Naphthylpropylcarboxylic acid (NaPA) was used as a self-assembled hole-selective material to prepare perovskite-based solar cells, such as Figure 1 As shown, the structure of the perovskite-based solar cell is ITO / SAM / perovskite / PC61BM / BCP / Ag.

[0044] The preparation method of the perovskite-based solar cell comprises the following steps: ultrasonically cleaning the ITO conductive glass with a glass cleaning agent, acetone and isopropanol for 30 minutes in sequence. After the ITO glass is cleaned with an N2 air gun, plasma cleaning is performed for 30 minutes. The naphthyl propyl carboxylic acid (NaPA) prepared in Example 1 is used as a hole selective contact layer, and the naphthyl propyl carboxylic acid (NaPA) is prepared into a solution with a concentration of 0.6 mg mL -1 ethanol solution, 70 μL of naphthylpropylcarboxylic acid (NaPA) solution was pipetted onto the ITO glass, and the glass was rotated at 1000 rpm for 10 seconds, 3000 rpm for 30 seconds, and thermally annealed at 120°C for 20 minutes. 0.05 MA 0.05FA 0.9 PbI 2.95 Br 0.05 The perovskite solution was spin-coated onto the surface of naphthylpropyl carboxylic acid (NaPA) and thermally annealed at 120 °C for 25 minutes. After cooling, 30 nm PC 61 BM and 3 nm of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) were spin-coated onto the perovskite film surface. Finally, 120 nm of Ag was thermally evaporated in vacuum as the top electrode, thus completing the preparation of the perovskite-based solar cell device, and the effective area of the device was 0.1 cm 2 .

[0045] Application Example 2:

[0046] The difference between the perovskite-based solar cell in this application example and that in Application Example 1 is only that an ethanol solution with a solution concentration of 0.6 mg mL -1 was prepared from anthracenylpropyl carboxylic acid (AnPA) and spin-coated to prepare the hole-selective contact layer.

[0047] Application Example 3:

[0048] The difference between the perovskite-based solar cell in this application example and that in Application Example 1 is only that an ethanol solution with a solution concentration of 0.6 mg mL -1 was prepared from pyrenylpropyl carboxylic acid (JR1) and spin-coated to prepare the hole-selective contact layer.

[0049] Application Example 4:

[0050] The difference between the perovskite-based solar cell in this comparative example and that in Application Example 1 is only that an ethanol solution with a solution concentration of 0.6 mg mL -1 was prepared from pyrenylpropyl carboxylic acid (JR0) and spin-coated to prepare the hole-selective contact layer.

[0051] Application Example 5:

[0052] The difference between the perovskite-based solar cell in this comparative example and that in Application Example 1 is only that an ethanol solution with a solution concentration of 0.6 mg mL -1 was prepared from anthracenylpropyl carboxylic acid (PTPA) and spin-coated to prepare the hole-selective contact layer.

[0053] Sample Analysis

[0054] First, a monolayer (SAM) of polycyclic aromatic hydrocarbon carboxylic acid derivatives of Application Examples 1-5 was prepared on ITO glass by spin coating. After XPS testing, it was proved that the alkyl carboxylic acids on naphthylpropyl carboxylic acid (NaPA), anthracenylpropyl carboxylic acid (AnPA), pyrenylpropyl carboxylic acid (JR0), anthracenylpropyl carboxylic acid (PTPA), and pyrenylpropyl carboxylic acid (JR1) had strong chemisorption with indium oxide on the ITO surface.

[0055] Then, after the devices in Application Examples 1-5 were fabricated, a xenon lamp solar simulator was used to test the light source intensity at AM1.5G (100 mW cm -2 ), and the open-circuit voltage (V oc ), short-circuit current density (J sc ), fill factor (FF), and power conversion efficiency (PCE) of the perovskite solar cells based on polycyclic aromatic hydrocarbon carboxylic acid derivatives were tested.

[0056] The current-voltage (J-V) characteristic curve of the perovskite-based solar cell device prepared in Application Example 1 is shown in Figure 3 . Among them, the open-circuit voltage (V oc ) of the perovskite-based solar cell device based on naphthylpropyl carboxylic acid (NaPA) is 0.963 V, and the short-circuit current density J sc is 21.83 mA cm -2 , the fill factor FF is 0.749, and the power conversion efficiency can reach 15.74%.

[0057] The current-voltage (J-V) characteristic curve of the perovskite-based solar cell device prepared in Application Example 2 is shown in Figure 4 . Among them, the open-circuit voltage (V oc ) of the perovskite-based solar cell device based on anthracenylpropyl carboxylic acid (AnPA) is 1.027 V, and the short-circuit current density J sc is 24.62 mA cm -2 , the fill factor FF is 0.769, and the power conversion efficiency is 19.44%.

[0058] The current-voltage (J-V) characteristic curve of the perovskite-based solar cell device prepared in Application Example 3 is shown in Figure 5 . Among them, the open-circuit voltage (V oc ) of the perovskite-based solar cell device based on pyrenylpropyl carboxylic acid (JR1) is 1.073 V, and the short-circuit current density J sc is 25.33 mA cm -2 , the fill factor FF is 0.788, and the power conversion efficiency is 21.41%.

[0059] The current-voltage (J-V) characteristic curve of the perovskite-based solar cell device prepared in Application Example 4 is shown in Figure 6 . Among them, the open-circuit voltage (V oc ) of the perovskite-based solar cell device based on pyrenylpropyl carboxylic acid (JR0) is 1.0249 V, and the short-circuit current density J sc is 25.91 mA cm -2 , the fill factor FF is 0.741, and the power conversion efficiency is 19.70%.

[0060] The current-voltage (J-V) characteristic curve of the device performance of the perovskite-based solar cell prepared in Application Example 5 is shown in Figure 7 . Among them, the open-circuit voltage (V oc ) of the perovskite-based solar cell device based on anthracenepropylcarboxylic acid (PTPA) is 1.045 V, and the short-circuit current density J sc is 25.85 mA cm -2 , the fill factor FF is 0.757, and the photoelectric conversion efficiency is 20.46%.

[0061] In summary, when the polycyclic aromatic hydrocarbon carboxylic acid derivative is used as a self-assembled hole-selective material to prepare a perovskite-based solar cell, a photoelectric conversion efficiency of >15% can be obtained. The polycyclic aromatic hydrocarbon carboxylic acid derivative promotes charge transport, reduces the overall series resistance of the device, and improves the photoelectric conversion efficiency of the perovskite-based device.

[0062] The present invention is not limited to the above best implementation manner. Any person can obtain other various forms of products under the inspiration of the present invention. However, no matter what changes are made in its shape or structure, as long as it has the same or similar technical solutions as the present application, it falls within the protection scope of the present invention.

Claims

1. A perovskite-based solar cell, characterized in that, It includes a transparent conductive substrate, a hole-selective contact layer, a perovskite light absorption layer, an electron transport layer, a modification layer and a top electrode. The hole-selective contact layer is prepared from a polycyclic aromatic hydrocarbon carboxylic acid derivative, wherein the polycyclic aromatic hydrocarbon carboxylic acid derivative uses a polycyclic aromatic hydrocarbon unit with a rigid large π-conjugated plane as the parent nucleus and an alkyl carboxylic acid as the chemical anchoring group, and the structural formula is shown in formula (I): ； Wherein the polycyclic aromatic hydrocarbon unit does not contain other heteroatoms and is selected from any one of the following structural formulas: Wherein n in the structural formula (I) is an integer from 1 to 10; The R groups are independently selected from hydrogen, linear alkyl, linear alkenyl, linear alkynyl, alkoxy and cyclic alkyl with or without substituents. Among them, the linear alkyl and cyclic alkyl are selected as C1-C40 alkyl; the linear alkenyl and cyclic alkenyl are selected as C2-C40 alkenyl; the linear alkynyl is selected as C3-C40 alkynyl; the linear alkoxy and cyclic alkoxy are selected as C1-C40 alkoxy.

2. The perovskite-based solar cell according to claim 1, characterized in that, The substituents in the R group are one of methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, methoxy, ethoxy, propoxy, methylthio, ethylthio, propylthio, hydroxyl, carboxyl, mercapto, fluorine atom, chlorine atom, bromine atom, iodine atom, methylamino or aldehyde group.

3. The perovskite-based solar cell according to claim 1, wherein The polycyclic aromatic hydrocarbon carboxylic acid derivatives are NaPA, PTPA, and the structural formulas are shown as follows: 。 4. The perovskite-based solar cell according to claim 1, characterized in that, The self-assembled hole-selective contact layer is prepared by using the polycyclic aromatic hydrocarbon carboxylic acid derivative through methods such as soaking, blade coating, spin coating, LB film pulling or evaporation.

5. The perovskite-based solar cell according to claim 1, wherein The photoelectric conversion efficiency of the perovskite-based solar cell > 15%.

6. The perovskite-based solar cell according to claim 1, wherein, The perovskite-based solar cell is used as one of the sub-cells of a single-junction device or a four-terminal silicon / perovskite tandem solar cell, CIGS / perovskite tandem solar cell or organic / perovskite tandem solar cell.

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