Perovskite solar cell

Abstract

The invention provides a perovskite solar cell. The perovskite solar cell comprises a conductive substrate; a hole transport layer; a polymer hydrophobic layer; the polymer hydrophobic layer is formed by polymer ionic liquid; a perovskite thin film layer; an electron transport layer; an electrode layer; the polymer ionic liquid comprises a structure as shown in a formula (I). Compared with the prior art, the polymer ionic liquid provided by the invention has hydrophobicity and can effectively block invasion of water vapor to a perovskite layer when being applied; secondly, a monomer in the polymer ionic liquid contains imidazole, C-H in the monomer can form hydrogen bonds with halogen atoms in the perovskite, the interaction between a polymer chain and the perovskite is enhanced, and the phase change of the perovskite is inhibited; in addition,-SO3-at one end of the polymer ionic liquid can be combined with Pb < 2 + > in perovskite through electrostatic interaction, phase change of the polymer ionic liquid is further inhibited, and Pb leakage is reduced.

Description

Technical Field

[0001] This invention belongs to the field of solar cell technology, and particularly relates to a perovskite solar cell. Background Technology

[0002] With the continuous development of human society, the demand for energy is increasing. Traditional energy sources, such as oil, natural gas, and coal, are non-renewable energy sources. Not only are their reserves dwindling, but they also cause significant environmental pollution. Therefore, vigorously developing renewable, green, and clean energy sources is extremely urgent and important. Among them, solar energy stands out, being inexhaustible and environmentally friendly, and its application research has received increasing attention. Developing clean, pollution-free, and abundant solar energy has become a hot topic of research for scientists. Organic-inorganic hybrid perovskite solar cells (PSCs) have significant advantages such as low cost, high conversion efficiency, and suitability for industrial production. Since their introduction in 2009, their photoelectric conversion efficiency has rapidly increased to 26.1%.

[0003] The most challenging issue for perovskite scaffolds (PSS) is their long-term stability, which must be addressed before they can be applied in practical applications. It is well known that the stability of PSSs in harsh environments (such as heat treatment, lighting, and humidity) is a major bottleneck hindering their commercialization. Among these factors, water undoubtedly has the most significant impact on PSS stability. Water molecules can rapidly and easily form hydrogen bonds with non-coordinated I atoms on the perovskite surface, effectively reducing non-radiative recombination. Then, water vapor penetrates the perovskite surface and perovskite structural boundaries, forming reversible intermediates MAPbI3·H2O and MAPbI3·2H2O hydrates. Through strong hydrogen bonds between water and organic cations, the bonding between organic cations and the inorganic PbI6 scaffold can be weakened; this step is considered a key step in water-induced perovskite degradation. Furthermore, water can protonate iodides to form volatile halide acids, resulting in the production of yellow decomposition products of lead halides (PbX2) without photoelectric properties. Although low humidity may be beneficial to the morphology and carrier behavior of perovskites during deposition. However, it has been confirmed that water can severely damage perovskites in high humidity environments or during long-term use. It is particularly noteworthy that wide-bandgap perovskites, such as CsPbI3, used in tandem solar cells are highly sensitive to moisture; atmospheric moisture can also significantly accelerate the black-to-yellow phase transition. Summary of the Invention

[0004] In view of this, the technical problem to be solved by the present invention is to provide a perovskite solar cell, which includes a hydrophobic layer formed by a polymer ionic liquid. The polymer ionic liquid is hydrophobic and can effectively block water vapor from intruding into the perovskite layer.

[0005] This invention provides a perovskite solar cell, comprising:

[0006] Conductive substrate;

[0007] Hole transport layer;

[0008] A polymer hydrophobic layer; the polymer hydrophobic layer is formed of a polymer ionic liquid;

[0009] Perovskite thin film layer;

[0010] Electron transport layer;

[0011] Electrode layer;

[0012] The polymeric ionic liquid comprises the structure shown in formula (I):

[0013]

[0014] Where m is an integer from 2 to 6, p is an integer from 0 to 3, and n is an integer from 200 to 1000.

[0015] Preferably, it includes the structure shown in formula (II):

[0016]

[0017] Preferably, m is an integer from 3 to 5.

[0018] Preferably, the method for preparing the polymer ionic liquid includes the following steps:

[0019] S1) In a protective atmosphere, the 1-alkylenylimidazolium shown in formula (III) is reacted with the compound shown in formula (IV) to obtain the compound shown in formula (V);

[0020] S2) The compound shown in formula (V), the crosslinking agent, and the photoinitiator are mixed and reacted to obtain a polymeric ionic liquid;

[0021]

[0022] Where m is an integer from 2 to 6, and p is an integer from 0 to 3.

[0023] Preferably, the reaction in step S1) is carried out in an organic solvent; under a protective atmosphere, 1-alkylenylimidazolium of formula (III) is mixed with an organic solvent, and then the compound of formula (IV) is added under low temperature conditions, and the temperature is raised to carry out the reaction to obtain the compound of formula (V); the low temperature conditions are 0℃~5℃; the reaction temperature is 10℃~35℃; and the reaction time is 1~4 days.

[0024] Preferably, the crosslinking agent in step S2) is selected from polyethylene glycol diacrylate and / or polyethylene glycol dimethacrylate;

[0025] The photoinitiator is selected from one or more of benzoyl photoinitiators, alkyl benzophenone photoinitiators, and benzophenone photoinitiators;

[0026] The reaction in step S2) is carried out in an alcohol solvent; the mass concentration of the compound represented by formula (V) in the reaction system is 1% to 5%.

[0027] Preferably, the mass ratio of the compound shown in formula (V), the crosslinking agent, and the photoinitiator is (1-5):1:(0.01-0.5).

[0028] Preferably, the hole transport layer comprises one or more of the following: poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene, poly(3,4-ethylenedioxythiophene):polystyrene sulfonate, 4-butyl-N,N-diphenylaniline homopolymer, polyvinylcarbazole, CuI, and CuSCN;

[0029] The perovskite thin film layer comprises ABX3, wherein A is selected from CH3NH3. + CH(NH2)2 + Cs + With Rb + One or more of the following; B is selected from Pb 2+ Sn 2+ With Ge 2+ One or more of them; X is selected from Cl - ,Br - with I - One or more of the following;

[0030] The electron transport layer includes C 60 One or more of the following: PCBM, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, TiO2, SnO2, ZnO, and ZnO-ZnS.

[0031] Preferably, the thickness of the polymer hydrophobic layer is 1–10 nm; and the thickness of the perovskite thin film layer is 300–700 nm.

[0032] This invention provides a perovskite solar cell, comprising, in sequence: a conductive substrate; a hole transport layer; a polymer hydrophobic layer; the polymer hydrophobic layer being formed of a polymer ionic liquid; a perovskite thin film layer; an electron transport layer; and an electrode layer; the polymer ionic liquid comprising the structure shown in formula (I). Compared with the prior art, the polymer ionic liquid provided by this invention is hydrophobic, and when used as a hydrophobic layer in a perovskite solar cell, it can effectively block the intrusion of water vapor into the perovskite layer; secondly, the monomer in the polymer ionic liquid contains imidazole, wherein the CH can form hydrogen bonds with halogen atoms in the perovskite, enhancing the interaction between the polymer chain and the perovskite and suppressing the phase transition of the perovskite; furthermore, the -SO3 group at one end of the polymer ionic liquid... - It can also interact with Pb in perovskite through electrostatic interactions. 2+ Combined, this further suppresses the phase transition and reduces Pb leakage. Attached Figure Description

[0033] Figure 1 A schematic diagram illustrating the interaction between the polymer ionic liquid and perovskite provided by this invention;

[0034] Figure 2 The images show a comparison of the ultraviolet spectra of the perovskite films treated with different polymer ionic liquids in Examples 1, 4 and 5 of this invention with those of the perovskite film obtained in Comparative Example 1.

[0035] Figure 3 The images show the fluorescence spectra of the perovskite films treated with different polymer ionic liquids in Examples 1, 4, and 5 of this invention, and the perovskite films obtained in Comparative Example 1.

[0036] Figure 4 This is a comparison chart of the stability of perovskite solar cells obtained in Examples 1-5 and Comparative Example 1 of the present invention;

[0037] Figure 5 This is a comparison chart of lead concentration in aqueous solution after soaking perovskite solar cells obtained in Examples 1, 4, and 6 of the present invention with those obtained in Comparative Example 1 for 8 hours. Detailed Implementation

[0038] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0039] This invention provides a polymeric ionic liquid comprising the structure shown in formula (I):

[0040]

[0041] Where m is an integer from 2 to 6, preferably an integer from 3 to 5; p is an integer from 0 to 3, preferably an integer from 0 to 2, and even more preferably 0 or 1; n is an integer from 200 to 1000.

[0042] In one specific embodiment of the present invention, the polymeric ionic liquid comprises the structure shown in formula (II):

[0043]

[0044] The polymer ionic liquid provided by this invention is hydrophobic, effectively preventing water vapor from penetrating the perovskite layer. Secondly, the monomer in this polymer ionic liquid contains imidazole, where the CH group can form hydrogen bonds with halogen atoms in the perovskite, enhancing the interaction between the polymer chain and the perovskite and suppressing the phase transition of the perovskite. Furthermore, the -SO3 group at one end of the polymer ionic liquid... - It can also interact with Pb in perovskite through electrostatic interactions. 2+ This combination further suppresses the phase transition and reduces Pb leakage. See also Figure 1 , Figure 1 This is a schematic diagram illustrating the interaction between the polymer ionic liquid and perovskite provided by the present invention.

[0045] The present invention also provides a method for preparing the above-mentioned polymer ionic liquid, comprising the following steps: S1) reacting 1-alkylenylimidazolium shown in formula (III) with the compound shown in formula (IV) in a protective atmosphere to obtain the compound shown in formula (V); S2) mixing and reacting the compound shown in formula (V), a crosslinking agent and a photoinitiator to obtain the polymer ionic liquid;

[0046]

[0047] m is an integer from 2 to 6, preferably an integer from 3 to 5; p is an integer from 0 to 3, preferably an integer from 0 to 2, and even more preferably 0 or 1.

[0048] In this invention, there are no special restrictions on the source of any raw materials; they can be commercially available.

[0049] In a protective atmosphere, the 1-alkylenylimidazole of formula (III) is reacted with the compound of formula (IV) to obtain the compound of formula (V); the protective atmosphere can be any atmosphere known to those skilled in the art and is not particularly limited, but nitrogen is preferred in this invention; the molar ratio of the 1-alkylenylimidazole of formula (III) to the compound of formula (IV) is preferably 1:(0.8-1.2), more preferably 1:1; the reaction is preferably carried out in an organic solvent; the organic solvent can be any organic solvent known to those skilled in the art and is not particularly limited, but acetone is preferred in this invention; in this invention, preferably, the 1-alkylenylimidazole of formula (III) is mixed with an organic solvent in a protective atmosphere, and then the compound of formula (IV) is added under low temperature conditions. The compound shown in formula (IV) is reacted by heating to obtain the compound shown in formula (V); the temperature of the low-temperature condition is preferably 0℃~5℃; the compound shown in formula (IV) is preferably dissolved in an organic solvent and added dropwise to the reaction system; the concentration of 1-alkylenylimidazolium shown in formula (III) in the reaction system is preferably 5%~15%, more preferably 8%~12%, and even more preferably 9%~10%; the reaction temperature is preferably 10℃~35℃, more preferably 15℃~35℃, and even more preferably 20℃~30℃; the reaction time is preferably 1~4 days, more preferably 2~4 days, and even more preferably 3 days; after the reaction is completed, it is preferably filtered, washed, and dried to obtain the compound shown in formula (V); the drying is preferably vacuum drying; the drying is preferably carried out at room temperature.

[0050] The compound shown in formula (V), a crosslinking agent, and a photoinitiator are mixed and reacted to obtain a polymeric ionic liquid; the crosslinking agent is preferably a polyethylene glycol acrylate crosslinking agent, more preferably polyethylene glycol diacrylate and / or polyethylene glycol dimethacrylate; the photoinitiator is preferably one or more of benzoyl photoinitiators, alkyl benzophenone photoinitiators, and benzophenone photoinitiators, more preferably 2-hydroxy-2-methyl-1-phenylpropanone (1173), 1-hydroxycyclohexylphenyl ketone (184), 2-methyl-2-(4-morpholino)-1-[4-(methylthio)phenyl]-1-propanone (907), 2-dimethylamino-2-benzyl-1-[4-(4-morpholino)phenyl]-1-butanone (IHT-PI) 910) and one or more of 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone (659); the mass ratio of the compound shown in formula (V), the crosslinking agent and the photoinitiator is preferably (1-5):1:(0.01-0.5), more preferably (2-4):1:(0.05-0.3), even more preferably (2.5-3.5):1:(0.05-0.2), and most preferably 3:1:0.1; the reaction is preferably carried out in an alcoholic solution. The reaction is carried out in an agent; the alcohol solvent can be any alcohol solvent well known to those skilled in the art, and there are no special restrictions. In this invention, methanol is preferred; the mass concentration of the compound represented by formula (V) in the reaction system is preferably 1% to 5%, more preferably 2% to 4%, and even more preferably 3%; the reaction temperature is preferably 10℃ to 35℃, more preferably 15℃ to 35℃, even more preferably 20℃ to 30℃, and most preferably 25℃; the reaction time is preferably 1 to 4 hours, more preferably 2 to 3 hours.

[0051] In one specific embodiment of the present invention, the polymer ionic liquid is prepared in the following manner:

[0052]

[0053] The present invention also provides a perovskite solar cell, comprising, in sequence: a conductive substrate; a hole transport layer; a polymer hydrophobic layer; the polymer hydrophobic layer being formed of the aforementioned polymer ionic liquid; a perovskite thin film layer; an electron transport layer; and an electrode layer.

[0054] The conductive substrate can be any conductive substrate known to those skilled in the art, and there are no special restrictions. In this invention, transparent conductive glass is preferred.

[0055] A hole transport layer is disposed on the surface of the conductive substrate; the thickness of the hole transport layer is preferably 10-50 nm, more preferably 20-40 nm, and even more preferably 30 nm; the hole transport layer preferably includes one or more of poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (Spiro-OMeTAD), poly(3,4-ethylenedioxythiophene:polystyrene sulfonate (PEDOT:PSS), 4-butyl-N,N-diphenylaniline homopolymer (Ploy-TPD), polyvinylcarbazole (PVK), CuI, and CuSCN.

[0056] A polymer hydrophobic layer is disposed on the surface of the hole transport layer away from the conductive substrate; the thickness of the polymer hydrophobic layer is preferably 1-10 nm, more preferably 1-8 nm, even more preferably 1-6 nm, and most preferably 2-5 nm.

[0057] A perovskite thin film layer is disposed on the surface of the polymer hydrophobic layer away from the hole transport layer; the thickness of the perovskite thin film layer is preferably 300-700 nm, more preferably 400-600 nm, and even more preferably 500 nm; the perovskite thin film layer preferably comprises ABX3, wherein A is preferably CH3NH3. + (MA + CH(NH2)2 + (FA + ), Cs + With Rb + One or more of the following; B is preferably Pb. 2+ Sn 2+ With Ge 2+ One or more of them; X is preferably Cl - ,Br - with I - One or more of them.

[0058] An electron transport layer is disposed on the surface of the perovskite thin film away from the polymer hydrophobic layer; the thickness of the electron transport layer is preferably 10-50 nm, more preferably 10-40 nm, and even more preferably 20-30 nm; the electron transport layer preferably includes C 60 One or more of the following: PCBM, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, TiO2, SnO2, ZnO, and ZnO-ZnS.

[0059] An electrode layer, i.e., a back electrode, is disposed on the surface of the electron transport layer away from the perovskite thin film layer; the thickness of the electrode layer is preferably 50-150 nm, more preferably 80-100 nm; the electrode layer can be any electrode layer known to those skilled in the art, and there are no special limitations. In this invention, it is preferably any one of Al, Au, Ag or low-temperature carbon electrode.

[0060] The present invention also provides a method for preparing the above-mentioned perovskite solar cell, comprising the following steps: A1) coating a solution containing a hole transport material onto the surface of a conductive substrate and annealing to form a hole transport layer; A2) coating a solution containing a polymer ionic liquid onto the surface of the hole transport layer and annealing to form a polymer hydrophobic layer; A3) coating a perovskite precursor solution onto the surface of the polymer hydrophobic layer and annealing to form a perovskite thin film layer; A4) forming an electron transport layer on the surface of the perovskite thin film layer; A5) forming an electrode layer on the surface of the electron transport layer to obtain a perovskite solar cell.

[0061] In this invention, there are no special restrictions on the source of any raw materials; they can be commercially available.

[0062] A solution containing a hole transport material is coated onto the surface of a conductive substrate and annealed to form a hole transport layer. The concentration of the hole transport material in the solution is preferably 30–100 mg / mL, more preferably 40–80 mg / mL, even more preferably 60–70 mg / mL, and most preferably 75 mg / mL. The coating method can be any method well-known to those skilled in the art and is not particularly limited; spin coating is preferred in this invention. The spin coating speed is preferably 2000–8000 rpm, more preferably 4000–6000 rpm, and even more preferably 5000 rpm. The spin coating time is preferably 30–80 s, more preferably 40–60 s, and even more preferably 50 s. The annealing temperature is preferably 110℃–150℃, more preferably 120℃–130℃. The annealing time is preferably 10–40 min, more preferably 20–30 min, and even more preferably 25 min.

[0063] A solution containing a polymer ionic liquid is coated onto the surface of the hole transport layer, followed by annealing to form a polymer hydrophobic layer. The concentration of the polymer ionic liquid in the solution is preferably 0.5–3.5 mg / mL, more preferably 1–3 mg / mL, and even more preferably 1–2 mg / mL. The solvent in the solution is preferably an alcohol solvent and / or a ketone solvent, more preferably one or more of methanol, ethanol, and acetone. The coating method can be any method well-known to those skilled in the art and is not particularly limited; however, in this invention, the preferred method is... Spin coating; the spin coating speed is preferably 2000-8000 rpm, more preferably 4000-6000 rpm, and even more preferably 5000 rpm; the spin coating time is preferably 30-80 s, more preferably 40-60 s, and even more preferably 45-50 s; the annealing temperature is preferably 80℃-150℃, more preferably 80℃-120℃, even more preferably 90℃-110℃, and most preferably 100℃; the annealing time is preferably 5-30 min, more preferably 10-30 min, and even more preferably 15-20 min.

[0064] A perovskite precursor solution is coated onto the surface of the polymer hydrophobic layer, followed by annealing to form a perovskite thin film layer. The perovskite precursor solution is preferably a solution containing AX and BX. The concentration of BX in the solution containing AX and BX is preferably 0.5–3 mol / L, more preferably 1–2 mol / L, and even more preferably 1.5 mol / L. The solvent of the solution containing AX and BX is preferably a mixed solvent of dimethyl sulfoxide and dimethylformamide. The volume ratio of dimethyl sulfoxide to dimethylformamide is preferably 1:(5–15), more preferably 1:(8–12), and even more preferably 1:9. The coating method is as follows: Any method familiar to those skilled in the art is acceptable and there are no special limitations. Spin coating is preferred in this invention. The spin coating speed is preferably 2000-8000 rpm, more preferably 4000-6000 rpm, and even more preferably 5000 rpm. The spin coating time is preferably 30-80 s, more preferably 40-60 s, and even more preferably 45-50 s. The annealing temperature is preferably 100℃-150℃, more preferably 100℃-130℃, and even more preferably 110℃-120℃. The annealing time is preferably 5-30 min, more preferably 10-30 min, and even more preferably 15-20 min.

[0065] An electron transport layer is formed on the surface of the perovskite thin film layer; the method for forming the electron transport layer is any method well known to those skilled in the art and is not particularly limited. In this invention, vapor deposition is preferred, and vacuum vapor deposition is more preferred; the vacuum degree of the vapor deposition is preferably 4 × 10⁻⁶. -4 ~6×10 -4 Pa, more preferably 5 × 10 Pa-4 Pa; the evaporation rate of the vapor deposition is preferably 0.1 to 0.2 A / s, more preferably 0.15 to 0.2 A / s.

[0066] An electrode layer is formed on the surface of the electron transport layer to obtain a perovskite solar cell. The method for forming the electrode layer can be any method well-known to those skilled in the art and is not particularly limited. In this invention, vapor deposition is preferred, and vacuum vapor deposition is more preferred. The vacuum degree of the vapor deposition is preferably 4 × 10⁻⁶. -4 ~6×10 -4 Pa, more preferably 5 × 10 Pa -4 Pa; the evaporation rate of the vapor deposition is preferably 0.1 to 0.2 A / s, more preferably 0.15 to 0.2 A / s.

[0067] To further illustrate the present invention, the following describes in detail, with reference to embodiments, a polymer ionic liquid provided by the present invention, its preparation method, and its application in perovskite solar cells.

[0068] All reagents used in the following examples are commercially available.

[0069] Example 1

[0070] Step 1: Clean the transparent conductive glass, specifically by ultrasonic cleaning with detergent, deionized water, acetone and anhydrous ethanol respectively, and then drying it with a nitrogen gun; the ultrasonic cleaning power is 100Hz and the ultrasonic cleaning time is 15min.

[0071] Step 2: Deposit a hole transport layer on the conductive glass surface by spin coating. Specifically, a hole transport layer solution with a concentration of 65 mg / mL prepared by PEDOT:PSS is dropped onto the conductive glass in Step 1 and spin-coated at 5000 rpm for 50 s. Then, it is annealed at 120°C for 25 min to obtain a hole transport layer with a thickness of approximately 30 nm.

[0072] Step 3: Prepare the polymer ionic liquid layer by spin-coating a methanol solution (2 mg / mL) containing substance A onto the hole transport layer at a speed of 5000 rpm for 45 s, followed by annealing at 100 °C for 15 min. The thickness is approximately 2-5 nm.

[0073] Step 4: Prepare the perovskite light-absorbing layer, specifically including:

[0074] MAI, FAI, MACl, and PbI2 were dissolved in a mixed solvent composed of dimethyl sulfoxide (DMSO) and dimethylformamide (DMF). The solution was heated at 70°C and stirred continuously for 1 hour until completely dissolved, thus obtaining a perovskite precursor solution. The concentration ratio of FAI:MAI:MACl was 0.95:0.05:0.14, the concentrations of FAI and PbI2 were both 1.5M (M is the molar concentration, i.e., mol / L), and the volume ratio of dimethyl sulfoxide (DMSO) to dimethylformamide (DMF) in the mixed solvent was 1:9.

[0075] Perovskite films were prepared by spin coating at 5000 rpm for 50 seconds, followed by annealing at 120°C for 15 minutes to crystallize and form a FA film with a thickness of approximately 500 nm. 0.95 MA 0.05 PbI3 perovskite light-absorbing layer.

[0076] Step 5: Deposit an electron transport layer C on the surface of the perovskite layer using vacuum evaporation. 60 The evaporation is carried out under a vacuum of 5×10⁻⁶. -4 The process was carried out under Pa conditions, with an evaporation rate of 0.15 A / s and a thickness of approximately 20 nm.

[0077] Step 6: Deposit another electron transport layer BCP on the surface of the electron transport layer using vacuum evaporation, wherein the evaporation is performed at a vacuum degree of 5×10⁻⁶. -4 The process was carried out under Pa conditions, with an evaporation rate of 0.2 A / s and a thickness of approximately 8 nm.

[0078] Step 7: Fabricate a metal electrode on the upper surface of the BCP using PVD. In a metal evaporation chamber, a silver electrode with a thickness of 80 nm to 100 nm is formed on the surface of the electron transport layer opposite to the perovskite light-absorbing layer using a thermal evaporation process, serving as the metal cathode; wherein the vacuum degree of the evaporation chamber is 5 × 10⁻⁶. -4 Pa, evaporation rate is 2A / s.

[0079] Example 2

[0080] The difference between this embodiment and Embodiment 1 is that substance A in step 3 is replaced with an equal amount of substance B, while the rest of the preparation methods and parameters remain the same as in Embodiment 1.

[0081] Example 3

[0082] The difference between this embodiment and Embodiment 1 is that substance A in step 3 is replaced with an equal amount of substance C, while the rest of the preparation methods and parameters remain the same as in Embodiment 1.

[0083] Example 4

[0084] The difference between this embodiment and Embodiment 1 is that substance A in step 3 is replaced with an equal amount of substance D, while the rest of the preparation methods and parameters remain the same as in Embodiment 1.

[0085] Example 5

[0086] The difference between this embodiment and Embodiment 1 is that substance A in step 3 is replaced with an equal amount of substance E, while the rest of the preparation methods and parameters remain the same as in Embodiment 1.

[0087] The general formulas for substances A, B, C, D, and E are as follows: m = 3 for substance A, m = 4 for substance B, m = 5 for substance C, m = 2 for substance D, and m = 6 for substance E.

[0088]

[0089] The preparation method of substance A is as follows:

[0090] Step 1: Dissolve 9.41 g of 1-vinylimidazole in 60 mL of acetone. Then, under a nitrogen atmosphere at 0 °C, add an equimolar amount (0.1 mol) of 1,3-propanesulfonyl lactone dissolved in 40 mL of acetone dropwise to the above solution. After stirring at room temperature for 3 days, filter the resulting solid and wash it with acetone at least three times. Finally, dry the obtained product under vacuum at room temperature to obtain the intermediate product.

[0091] Step 2: Dissolve 3 wt% intermediate product (i.e. monomer), 1 wt% crosslinking agent poly(ethylene glycol) diacrylate (PEGDA) and 0.1 wt% photoinitiator E1173 in methanol solution, and react at 25°C for 2 hours to obtain final product A.

[0092] The preparation of substance B is the same as that of substance A, except that the 1,3-propanesulfonate lactone in the first step is replaced with an equal amount of 1,4-butanesulfonate lactone, while the rest of the preparation methods and parameters remain the same.

[0093] The preparation of substance C is the same as that of substance A, except that the 1,3-propanesulfonate lactone in the first step is replaced with an equal amount of 1,5-pentanesulfonate lactone, while the rest of the preparation methods and parameters remain the same.

[0094] The preparation of substance D is the same as that of substance A, except that the 1,3-propanesulfonate lactone in the first step is replaced with an equal amount of 1,2-ethanesulfonate lactone, while the rest of the preparation methods and parameters remain the same.

[0095] The preparation of substance E is the same as that of substance A, except that the 1,3-propanesulfonate lactone in the first step is replaced with an equal amount of 1,6-hexanesulfonate lactone, while the rest of the preparation methods and parameters remain the same.

[0096] Example 6

[0097] The difference between this embodiment and Example 1 is that the concentration of substance A in step 3 is changed to 1 mg / mL, while the rest of the preparation methods and parameters remain the same as in Example 1.

[0098] Example 7

[0099] The difference between this embodiment and Example 1 is that the concentration of substance A in step 3 is changed to 3 mg / mL, while the rest of the preparation methods and parameters remain the same as in Example 1.

[0100] Example 8

[0101] The difference between this embodiment and Example 1 is that the concentration of substance A in step 3 is changed to 0.5 mg / mL, while the rest of the preparation methods and parameters remain the same as in Example 1.

[0102] Example 9

[0103] The difference between this embodiment and Example 1 is that the concentration of substance A in step 3 is changed to 3.5 mg / mL, while the rest of the preparation methods and parameters remain the same as in Example 1.

[0104] Comparative Example 1

[0105] The difference between this comparative example and Example 1 is that step 3 was omitted, i.e., the polymer ionic liquid was not spin-coated. The remaining preparation methods and parameters are consistent with those of Example 1.

[0106] Optical characterization (UV spectroscopy and fluorescence spectroscopy) was performed on the perovskite films treated with different polymer ionic liquids in Examples 1, 4, and 5, as well as the perovskite film obtained in Comparative Example 1. The testing methods were as follows: UV spectroscopy: the UV measurement range was 400-900 nm; Fluorescence spectroscopy: the steady-state fluorescence spectrum of the perovskite layer was measured using a xenon lamp (Xe 900) with a wavelength of 500 nm; the obtained UV spectra are shown below. Figure 2 As shown, the fluorescence spectrum was obtained as follows. Figure 3 As shown. From Figure 2 The ultraviolet spectrum shows that FA after treatment with ionic liquid... 0.95 MA 0.05 The absorption peak of the PbI3 perovskite film shows a slight red shift, mainly because the monomer in the polymer ionic liquid contains imidazole, where the CH group can form hydrogen bonds with halogen atoms in the perovskite, enhancing the interaction between the polymer chain and the perovskite. Simultaneously, the -SO3 group at one end of the polymer ionic liquid... - It can also interact with Pb in perovskite through electrostatic interactions. 2+ This combination not only suppresses the phase transition but also effectively promotes the crystallization of perovskite films, resulting in larger final perovskite sizes. Simultaneously, from... Figure 3 The fluorescence spectrum shows that after treatment, FA 0.95 MA 0.05 The emission peak of the fluorescence spectrum of the PbI3 film was significantly improved, further demonstrating that the perovskite film formation quality was higher.

[0107] The performance of the perovskite solar cells provided in Examples 1 to 9 and the comparative examples was tested, and the results are shown in Table 1.

[0108] The JV performance of solar cell devices is mainly measured by the following four parameters: power conversion efficiency (PCE), short-circuit current density (Jsc), open-circuit voltage (Voc), and fill factor (FF).

[0109] This invention uses a solar energy simulation testing system for measurement. The light source is a 500W xenon lamp solar spectrum simulator, calibrated with a standard silicon cell KG-5, and measurements are taken under a solar intensity (AM 1.5G: 100mW / cm2). By applying a continuously varying voltage (-0.5V-1.2V) across the battery terminals and measuring the battery's output current (using a Keithley 2400 power supply), the product of these two measurements yields the JV test curve, displaying the device's photoelectric conversion efficiency under different conditions.

[0110] The battery stability test conditions are as follows: the test is conducted in a glove box without encapsulation.

[0111] Table 1 Performance parameters of perovskite solar cells after different polymer ionic liquid treatments.

[0112] Serial Number Voc(V) Jsc(mA / cm2) FF (%) PCE (%) Example 1 1.21 25.0 78.3 23.7 Example 2 1.21 25.1 78.0 23.7 Example 3 1.20 25.2 77.9 23.5 Example 4 1.15 24.3 76.6 21.4 Example 5 1.15 24.5 77.0 21.7 Example 6 1.19 25.5 77.7 23.6 Example 7 1.21 24.8 77.9 23.4 Example 8 1.18 24.6 76.4 22.2 Example 9 1.17 24.8 76.7 22.3 Comparative Example 1 1.13 23.9 75.9 20.5

[0113] As shown in Table 1, the FA formed after the above polymer ionic liquid treatment 0.95 MA 0.05The PbI3 perovskite thin-film solar cell exhibits significant improvements in open-circuit voltage, short-circuit current, fill factor, and photoelectric conversion efficiency. Compared to carbon chain numbers of 3–5 (Examples 1–3), excessively small carbon chain numbers (Example 4) or excessively large carbon chain numbers (Example 5) significantly impact cell efficiency. Excessively large carbon chain numbers severely impair carrier transport, leading to decreased device efficiency; excessively small carbon chain numbers result in weak hydrophobicity, failing to effectively prevent moisture intrusion and indirectly affecting the perovskite film quality. Furthermore, when the concentration of the polymer ionic liquid is too low (Example 8), the number of hydrogen bonds formed between the CH atoms in the polymer ionic liquid and the halogen atoms in the perovskite decreases, and the -SO3 group at one end of the polymer ionic liquid... - The effect of electrostatic interaction and the combination of Pb2+ in the perovskite is also weakened, which cannot effectively suppress its phase transition. At the same time, it cannot effectively block water vapor intrusion, resulting in poor film stability and decreased battery efficiency. When the concentration of the above polymer ionic liquid is too high (Example 9), it may form a stack on the surface of the perovskite film, hindering carrier transport and affecting battery efficiency.

[0114] Figure 4 This is a comparison of the stability of perovskite solar cells after treatment with different organic ionic compounds. From... Figure 4 It can be seen that the stability of perovskite solar cells treated with polymer ionic liquids is significantly enhanced, while the efficiency of untreated cells is only 50% of the initial value after 1000 hours. The figure also shows that when the number of carbon chains is large (Example 5), the stability of the cell is greatly improved. However, when the number of carbon chains is small (Example 4), although the stability is improved to some extent, it is still not as good as that of ionic compounds with a large number of carbon chains. This is because long-chain ionic compounds have better hydrophobicity and a more significant effect on isolating water vapor, thus resulting in better stability.

[0115] Figure 5 A comparison of lead concentration in aqueous solution after immersion for 8 hours in perovskite solar cells prepared without treatment and after treatment with different polymer ionic liquids. Figure 5 It can be seen from the aqueous solution of Comparative Example 1 that Pb 2+ The concentration was 0.3774 ppm, while the Pb concentration after polymer ionic liquid treatment was... 2+ The concentrations were 0.1559, 0.1743, and 0.1235 ppm, respectively, further demonstrating the presence of the -SO4 group at one end of the polymer ionic liquid. 3- It can interact with Pb in perovskite through electrostatic interactions. 2+ This combination significantly reduces lead leakage from the device. It further demonstrates that the hydrophobicity of the polymer ionic liquid increases with increasing carbon chain length, leading to a reduction in Pb content. 2+ The amount of leakage is decreasing.

[0116] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A perovskite solar cell, characterized in that, Including the following settings in sequence: Conductive substrate; Hole transport layer; A polymer hydrophobic layer; the polymer hydrophobic layer is formed of a polymer ionic liquid; Perovskite thin film layer; Electron transport layer; Electrode layer; The polymeric ionic liquid comprises the structure shown in formula (I): Where m is an integer from 2 to 6, p is an integer from 0 to 3, and n is an integer from 200 to 1000.

2. The perovskite solar cell according to claim 1, characterized in that, The polymeric ionic liquid comprises the structure shown in formula (II):

3. The perovskite solar cell according to claim 1, characterized in that, The value of m is an integer from 3 to 5.

4. The perovskite solar cell according to claim 1 is characterized in that, The preparation method of the polymer ionic liquid includes the following steps: S1) In a protective atmosphere, the 1-alkylenylimidazolium shown in formula (III) is reacted with the compound shown in formula (IV) to obtain the compound shown in formula (V); S2) The compound shown in formula (V), the crosslinking agent, and the photoinitiator are mixed and reacted to obtain a polymeric ionic liquid; Where m is an integer from 2 to 6, and p is an integer from 0 to 3.

5. The perovskite solar cell according to claim 4, characterized in that, The reaction in step S1) is carried out in an organic solvent; under a protective atmosphere, 1-alkylenylimidazolium of formula (III) is mixed with an organic solvent, and then the compound of formula (IV) is added under low temperature conditions, and the temperature is raised to carry out the reaction to obtain the compound of formula (V); the temperature of the low temperature conditions is 0℃~5℃; the temperature of the reaction is 10℃~35℃; and the reaction time is 1~4 days.

6. The perovskite solar cell according to claim 4, characterized in that, The crosslinking agent in step S2) is selected from polyethylene glycol diacrylate and / or polyethylene glycol dimethacrylate; The photoinitiator is selected from one or more of benzoyl photoinitiators, alkyl benzophenone photoinitiators, and benzophenone photoinitiators; The reaction in step S2) is carried out in an alcohol solvent; the mass concentration of the compound represented by formula (V) in the reaction system is 1% to 5%.

7. The perovskite solar cell according to claim 4, characterized in that, The mass ratio of the compound shown in formula (V), the crosslinking agent, and the photoinitiator is (1-5):1:(0.01-0.5).

8. The perovskite solar cell according to claim 1, characterized in that, The hole transport layer comprises one or more of the following: poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene, poly(3,4-ethylenedioxythiophene):polystyrene sulfonate, 4-butyl-N,N-diphenylaniline homopolymer, polyvinylcarbazole, CuI, and CuSCN.

9. The perovskite solar cell according to claim 1, characterized in that, The perovskite thin film layer comprises ABX3, wherein A is selected from CH3NH3. + CH(NH2)2 + Cs + With Rb + One or more of the following; B is selected from Pb 2+ Sn 2+ With Ge 2+ One or more of them; X is selected from Cl - ,Br - with I - One or more of the following; The electron transport layer includes C 60 One or more of the following: PCBM, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, TiO2, SnO2, ZnO, and ZnO-ZnS.

10. The perovskite solar cell according to claim 8, characterized in that, The thickness of the polymer hydrophobic layer is 1–10 nm; the thickness of the perovskite thin film layer is 300–700 nm.

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