A halide ammonium salt for passivating perovskite defects, perovskite solar cell, and manufacturing method and application

Abstract

The application provides a halide ammonium salt which can be used in a perovskite solar cell (PSC) to passivate perovskite Pb-I halide defects and a perovskite solar cell thereof. After the halide ammonium salt is applied to interface regulation of perovskite, defects of the perovskite are reduced, and photoelectric conversion efficiency and stability of the device are improved, and the application belongs to the field of sustainable green energy. The PSC prepared based on the application has a photoelectric conversion efficiency of more than 20%, and after being stored in a hole with a relative humidity of 40% to 50% at 25 DEG C for 1700 hours, the battery efficiency can be maintained at more than 80% of the initial efficiency.

Description

Technical Field

[0001] This invention belongs to the field of green and sustainable energy, specifically relating to an ammonium halide salt for passivating perovskite defects, perovskite solar cells, their preparation methods and applications. Background Technology

[0002] Since its first report in 2009, the photoelectric conversion efficiency of organic-inorganic hybrid PSCs has rapidly increased. Simultaneously, compared to commercially available silicon-based solar cells, PSCs have shown significant advantages in fabrication processes and cost control, thus attracting widespread attention from the scientific and commercial communities. Due to the relatively low defect formation energy of perovskite materials, high-density defects are easily formed during their fabrication, primarily including positively charged, poorly coordinated Pb. 2+ Negatively charged Pb-I antisite defects and insufficiently coordinated halide ions X - Defects. These defects can cause recombination of photogenerated charges, induce ion migration, and degrade perovskite. These factors are among the main reasons affecting the PCE and further improvement of the stability of PSC.

[0003] The interface modification materials reported in the literature for passivating perovskite surface defects can be summarized into two main categories: (1) Organic compounds containing negatively charged Lewis bases, such as thiophene, pyridine, phosphates, and halides; these compounds can effectively passivate positively charged, poorly coordinated Pb through coordination or electrostatic interactions. 2+ Defects. (2) Contains negatively charged Lewis acid organic compounds, such as fullerenes. These compounds can effectively passivate negatively charged Pb-I antisite defects and insufficiently coordinated halide ion defects. The results show that after surface passivation, perovskite can reduce defects and improve the long-term stability of the battery. However, the materials reported to be used to passivate perovskite have low mobility, and the energy levels of the passivated perovskite and the interface layer material are mismatched, thereby reducing the photoelectric performance of PSC (Zheng, X.;Chen, B.;Dai, J.;Fang, Y.;Bai, Y.;Lin, Y.;Wei, H.;Zeng, XC;Huang, J.,Defect passivation in hybridperovskite solar cells using quaternary ammonium halide anions and cations. Nature Energy 2017,2(7),1-9.). Summary of the Invention

[0004] This invention proposes an ammonium halide salt M(X) that can be used in perovskite solar cells (PSCs) to passivate Pb-I halide defects in perovskite. After the application of this ammonium halide salt to the interface of perovskite, the defects in perovskite can be reduced. Applying this type of material to perovskite solar cells (PSCs) can improve the photoelectric conversion efficiency and stability of the corresponding devices.

[0005] One objective of this invention is to provide an ammonium halide salt with the following general structural formula:

[0006]

[0007] Wherein, R is a saturated or unsaturated alkyl group containing at least one of carbonyl, ester, and mercapto groups; X is a halogen. Preferably, R is a saturated or unsaturated alkyl group containing at least one of carbonyl, ester, and mercapto groups with 2 to 20 carbon atoms, and more preferably a saturated or unsaturated alkyl group containing at least one of carbonyl, ester, and mercapto groups with 4 to 12 carbon atoms. X is preferably selected from Cl, Br, and I.

[0008] According to a specific embodiment of the present invention, the haloammonium salt is obtained by reacting a haloalkane with an amino compound.

[0009] A second objective of this invention is to provide a method for preparing the above-mentioned ammonium halide, comprising: dissolving a haloalkane in a solvent, adding an amine compound, and heating the mixture to react to obtain the ammonium halide.

[0010] Specifically, in the preparation method:

[0011] The haloalkane is selected from haloalkane having 1 to 6 carbon atoms, preferably from at least one of iodomethane, chloromethane, and bromomethane;

[0012] The amino compound is selected from at least one of amino fatty acids or their derivatives, preferably from at least one of dimethylaminoethyl methacrylate, carbamate dimethacrylate, diethylaminoethyl methacrylate, and aminomethyl methacrylate.

[0013] The molar ratio of the haloalkane to the amino compound is 1.5:1 to 10:1, preferably 2.5:1 to 6:1;

[0014] The solvent is selected from organic solvents and may be labeled as organic solvent S1, preferably at least one of dichloromethane, diethyl ether, and tetrahydrofuran;

[0015] The volume ratio of the haloalkane to the solvent is 1:0.1 to 1:10, preferably 1:1 to 1:5;

[0016] The heating reaction temperature is 40–100°C, and the heating reaction time is 5–24 h; preferably, the heating reaction temperature is 45–80°C, and the heating reaction time is 12–16 h.

[0017] The heating reaction is carried out in an inert atmosphere;

[0018] The haloammonium salt obtained from the heating reaction needs to be recrystallized. After cooling the solution obtained after the heating reaction, the solvent is removed, and the crude product can be used to obtain a white solid haloammonium salt by a common recrystallization process.

[0019] The third objective of this invention is to provide the above-mentioned ammonium halide salt, or the ammonium halide salt obtained according to the above preparation method, for use in perovskite solar cells.

[0020] A fourth objective of this invention is to provide a perovskite solar cell comprising the aforementioned ammonium halide or an ammonium halide obtained by the aforementioned preparation method. Preferably, the perovskite solar cell comprises, in sequence: a cathode substrate, a hole transport layer, a photoactive layer, an interface modification layer comprising the aforementioned ammonium halide, an electron transport layer, and a metal anode.

[0021] In a preferred embodiment of the present invention:

[0022] The cathode substrate is ITO glass;

[0023] The hole transport layer is a poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] layer;

[0024] The thickness of the hole transport layer is 5-20 nm, preferably 10-15 nm.

[0025] The photoactive layer is a perovskite photoactive layer; the perovskite photoactive layer can be any of the perovskite photoactive layers already existing in existing perovskite solar cells.

[0026] The thickness of the photoactive layer is 200–500 nm, preferably 300–400 nm;

[0027] The thickness of the interface modification layer is 1–10 nm, preferably 2–5 nm;

[0028] The electron transport layer includes C 60 The electron transport layer and the copper bath layer, preferably, the C 60 The thickness of the electron transport layer is 10–50 nm, and the thickness of the copper bath is 5–10 nm; more preferably, the C 60 The thickness of the electron transport layer is 20-30 nm, and the thickness of the copper bath is 6-8 nm;

[0029] The metal anode is selected from at least one of Ag and Cu;

[0030] The thickness of the metal anode is 50–200 nm, preferably 80–100 nm.

[0031] The fifth objective of this invention is to provide a method for preparing the above-mentioned perovskite solar cell, comprising preparing an interface modification layer containing the haloammonium salt, depositing an electron transport layer and a metal electrode by vapor deposition, thereby obtaining the perovskite solar cell. Preferably, the preparation method specifically includes the following steps:

[0032] Step 1: Preparation of the precursor solution:

[0033] (a) Add poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] powder (PTAA) to an organic solvent, which can be labeled as organic solvent S2. Toluene, a commonly used solvent, can be used. Stir to obtain a hole transport precursor solution.

[0034] (b) Dissolve lead iodide, lead bromide, methyl bromide, formamidine iodide and cesium iodide in a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide to obtain a perovskite precursor solution;

[0035] (c) Dissolve the haloammonium salt in an organic solvent, which can be labeled as organic solvent S3. Commonly used trifluoroethanol (TFE) can be used to obtain the haloammonium salt solution.

[0036] Step 2: Spin-coat the hole transport precursor solution onto indium tin oxide, and anneal to obtain an ITO / HTL thin film coated with a hole transport layer.

[0037] Step 3: Spin-coat the perovskite precursor solution onto the ITO / HTL film obtained in Step 2, and dry it to obtain an ITO / HTL / perovskite film coated with a perovskite photoactive layer.

[0038] Step 4: Spin-coat the ITO / HTL / perovskite film obtained in Step 3 with a halide ammonium salt solution to obtain an ITO / HTL / perovskite film with an interface modification layer.

[0039] Step 5: Evaporation of C 60 Electron transport layer, vapor-deposited copper bath;

[0040] Step 6: Evaporate metal electrodes.

[0041] Specifically, in the preparation method described:

[0042] The concentration of the hole transport precursor solution is 0.1–5 mg / mL, preferably 0.5–2.0 mg / mL;

[0043] In terms of volume percentage, the dimethyl sulfoxide in step b accounts for 1 to 20% of the total volume of the mixed solvent, preferably 5 to 10%.

[0044] The perovskite precursor solution is filtered through a polytetrafluoroethylene filter with a pore size of 0.45 μm before use.

[0045] In the perovskite precursor solution, based on 1 mL of the mixed solvent, the content of lead iodide is 400–700 mg, the content of lead bromide is 60–120 mg, the content of methyl bromide is 5–50 mg, the content of formamidine iodide is 100–250 mg, and the content of cesium iodide is 5–30 mg; preferably, based on 1 mL of the mixed solvent, the content of lead iodide is 450–600 mg, the content of lead bromide is 70–100 mg, the content of methyl bromide is 10–30 mg, the content of formamidine iodide is 150–210 mg, and the content of cesium iodide is 10–20 mg.

[0046] The concentration of the haloammonium salt solution is 0.1–5.0 mg / mL, preferably 0.1–1.0 mg / mL;

[0047] The annealing temperature in step two is 65–120°C, and the annealing time is 5–20 min; preferably, the annealing temperature is 80–100°C, and the annealing time is 5–10 min.

[0048] The drying temperature in step three is 80-150℃, preferably 90-120℃;

[0049] In step five, C is evaporated. 60 The electron transport layer and the vapor-deposited copper alloy can be obtained by vacuum evaporation methods and process conditions. For example, in a specific embodiment of the present invention, at a temperature below 1×10⁻⁶, -5 Under a vacuum of Pa, C 60 After being heated The rate is slowly evaporated onto the film obtained in step four to form a dense layer of a certain thickness, followed by the evaporation of a layer of bath copper spirit (BCP).

[0050] In step six, the electrode is deposited using common electrode evaporation process conditions. The metal electrode is selected from at least one of Ag and Cu. In a specific embodiment of the present invention, the vacuum chamber pressure during evaporation is maintained at less than 1 × 10⁻⁶. -4 Pa, with Ag was deposited at a certain rate.

[0051] This invention proposes a haloammonium salt-based M(X) ionization interface modification material with a strong electric dipole moment. This haloammonium salt compound possesses functional groups such as carbonyl and ester groups with lone pairs of electrons, which can passivate uncoordinated Pb defects in perovskites. Simultaneously, it has a relatively long alkyl chain, exhibiting some hydrophobicity, which improves the humidity stability of the device. This type of material not only passivates defects on the perovskite surface and reduces the probability of defect state charge recombination, but also improves charge transport and collection in PSCs, thereby significantly enhancing the photoelectric conversion efficiency (PCE) and stability of the PSC. After M(X) interface passivation, the PCE of the PSC is significantly improved, exceeding 20%, and the device stability is also significantly enhanced. After storage in holes at 25°C and a relative humidity of 40%–50% for 1700 hours, it still retains more than 80% of its initial efficiency.

[0052] The beneficial effects of this invention are as follows:

[0053] 1. The highest PCE of the PSC prepared based on M(X) interface modification is 20.4%, while the highest PCE of the PSC without interface modification is 18.8%. The corresponding JV curves are shown below. Figure 2 As shown;

[0054] 2. The device fabricated based on M(X) interface modification has a significantly higher efficiency than the control group. This is because M(X) interface modification reduces the transport resistance, resulting in better charge transfer and lower recombination (e.g., ...). Figure 3 This can improve the photovoltaic performance of the device;

[0055] 3. Unencapsulated PSCs fabricated based on M(X) interface modification exhibit excellent humidity stability. PSC devices based on M(X) interface modification can maintain more than 80% of their initial efficiency after being placed in an atmospheric environment with a humidity of 40%–50% and a temperature of 25°C for 1700 hours (i.e., T...). 80 =1700h). Attached Figure Description

[0056] Figure 1 The JV curves of the PSC prepared according to the present invention are shown, where a is the JV curve of the PSC obtained in Example 3 and b is the JV curve of the PSC obtained in Comparative Example 1.

[0057] Figure 2 Electrochemical impedance spectroscopy (EIS) tests were performed on the PSC prepared in this invention, wherein a is the EIS curve of the PSC obtained in Example 3, and b is the EIS curve of the PSC obtained in Comparative Example 1.

[0058] Figure 3The graphs show the humidity stability test curves of the PSC prepared according to the present invention, where a is the humidity stability test curve of the PSC obtained in Example 3, and b is the humidity stability test curve of the PSC obtained in Comparative Example 1. Detailed Implementation

[0059] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0060] The testing instruments and conditions used in this embodiment are as follows:

[0061] The JV curve is measured under specific illumination and temperature conditions. According to internationally recognized standard testing conditions for ground-mounted photovoltaic modules, the atmospheric quality is AM1.5, and the standard cell's solar irradiance is 1000 W·m². -2 The test temperature was 25℃. We used a Japanese XES-70S1 solar simulator to provide irradiation, and a Keithley 2400 from Keithley Instruments (USA) to record the current and voltage outputs to obtain the JV curve of the battery. During the test, a photomask was used to fix the active layer with an irradiated area of ​​0.1 cm². 2 .

[0062] Thickness measurement: Spectroscopic ellipsometer (M-2000V, JAWoollam Co., Lincoln, NE, USA).

[0063] The raw materials used in the examples are from the following sources:

[0064] The ITO used in the experiment had a thickness of 1.2mm, a transmittance of >80%, and a sheet resistance of 10Ω / sq. It was purchased from Shenzhen Nanbo Co., Ltd.

[0065] Other sources of raw materials are as follows:

[0066] reagents purity source acetone Analytical Pure Sinopharm Chemical Reagent Co., Ltd. Anhydrous ethanol Analytical Pure Sinopharm Chemical Reagent Co., Ltd. Isopropanol Analytical Pure Sinopharm Chemical Reagent Co., Ltd. DMF 99.8%, super dry Beijing Innocare Technology Co., Ltd. DMSO 99.8%, super dry Beijing Innocare Technology Co., Ltd. Toluene 99.9%, super dry Sigma Aldrich 2,2,2,-Trifluoroethanol 99％ Beijing Bailingwei Technology Co., Ltd. PTAA 99％ Xi'an Baolait Co., Ltd. Lead iodide 99.999％ Xi'an Baolait Co., Ltd. Lead bromide 99.999％ Xi'an Baolait Co., Ltd. Cesium iodide 99.999％ Xi'an Baolait Co., Ltd. Iodine Methylamidine 99％ Xi'an Baolait Co., Ltd. methyl bromide 99.9％ Xi'an Baolait Co., Ltd. <![CDATA[C 60 ]]> 99％ Xi'an Baolait Co., Ltd. BCP 99％ Xi'an Baolait Co., Ltd. Silver (Ag), Copper (Cu) 99.999％ Zhongnuo New Materials Technology Co., Ltd.

[0067] Example 1

[0068] Preparation of ITO / PTAA / Cs 0.05 FA 0.81 MA 0.14 PbI 2.55 Br 0.45 / M(Cl) / C 60 PSC of / BCP / Ag.

[0069] (a) Synthesis of interface modification material M(Cl)

[0070] 10 mL of dichloromethane solvent was added to a 50 mL two-necked flask, followed by 5 mL of dimethylaminoethyl methacrylate under an inert atmosphere, and then 5 mL of chloromethane was added dropwise. The reaction mixture was heated under reflux at 45 °C for 12 h. After cooling, the solvent was removed, and the crude product was recrystallized to obtain a white solid M(Cl).

[0071] (b)ITO / PTAA / Cs 0.05 FA 0.81 MA 0.14 PbI 2.55 Br 0.45 / M(Cl) / C 60 Fabrication of / BCP / Ag perovskite solar cells

[0072] Step 1: Preparation of the precursor solution:

[0073] Weigh 0.5 mg of PTAA, dissolve it in 1 mL of toluene and stir overnight to obtain a hole transport precursor solution.

[0074] Formulating Cs 0.05 FA 0.81 MA 0.14 PbI 2.55 Br 0.45 Perovskite precursor solution. Lead iodide (PbI₂) 470.7 mg, lead bromide (PbBr₂) 71.1 mg, methyl bromide (MABr) 18.9 mg, formamidinium iodide (FAI) 169.2 mg, and cesium iodide (CsI) 16.2 mg were dissolved in 1 mL of a mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO), wherein the volume ratio of DMF to DMSO was 95:5, to obtain a perovskite precursor solution. This solution was then stirred overnight on a hot plate at room temperature.

[0075] Weigh 1 mg of M(Cl) and dissolve it in 1 mL of TFE, stirring overnight to obtain an M(Cl) solution.

[0076] Step 2: Preparation of ITO / HTL thin films

[0077] The ITO transparent substrate was sequentially ultrasonically cleaned with deionized water, acetone, ethanol, and isopropanol for 20 minutes, dried with nitrogen, and then treated with ozone plasma for 15 minutes. The substrate was then placed in a nitrogen glove box for device fabrication. First, 30 μL of a toluene solution of PTAA was spin-coated onto the ITO substrate at 3000 rpm for 30 seconds. After spin-coating, the substrate was annealed at 90°C for 5 minutes to obtain a dense hole transport layer film with a thickness of 14 nm.

[0078] Step 3: Preparation of the perovskite active layer

[0079] Next, a perovskite precursor solution was spin-coated onto the ITO / PTAA film using an anti-solvent method. First, 60 μL of DMF solution was spin-coated at 5000 rpm for 20 s to increase the wettability of PTAA. Then, 60 μL of Cs was spin-coated. 0.05 FA 0.81 MA 0.14 PbI 2.55 Br 0.45 The solution was spin-coated at 3000 rpm for 28 seconds. 120 μL of the antisolvent toluene was slowly added dropwise 3 seconds before the end of the spin-coating. After spin-coating, the solution was annealed on a 90°C hot plate for 10 minutes to obtain a dense perovskite active layer with a thickness of 330 nm.

[0080] Step 4: Preparation of the interface modification layer

[0081] Subsequently, an interface modification layer was spin-coated. 50 μL of a TFE solution of M(Cl) was spin-coated onto the perovskite film at a speed of 4000 rpm for 50 s, resulting in an interface modification layer thickness of 4 nm.

[0082] Step 5: Evaporation of C 60 Electron transport layer, vapor-deposited copper bath

[0083] Next, an electron transport layer C with a thickness of approximately 20 nm was sequentially deposited in a vacuum evaporation apparatus. 60 An 8nm electrode modification layer of copper bath copper oxide (BCP). Below 1×10⁻⁸ nm. -5 Under a vacuum of Pa, C 60 After being heated The vapor is slowly deposited onto the film obtained in step four to form a dense layer of a certain thickness, followed by the deposition of a layer of bath copper (BCP).

[0084] Step 6: Deposit metal electrodes

[0085] The vacuum chamber pressure during vapor deposition is maintained at less than 1 × 10⁻⁶. -4 Pa, with An Ag electrode of 100 nm was deposited at a rate of [missing information].

[0086] Example 2

[0087] Preparation of ITO / PTAA / Cs 0.05 FA 0.81 MA 0.14 PbI 2.55 Br 0.45 / M(Br) / C 60 / BCP / Ag perovskite solar cells.

[0088] (a) Synthesis of interface modification material M(Br)

[0089] 10 mL of tetrahydrofuran solvent was added to a 50 mL two-necked flask, followed by 5 mL of dimethylaminoethyl ethyl acrylate under an inert atmosphere, and then 5 mL of methyl bromide was added dropwise. The reaction mixture was heated under reflux at 60 °C for 16 h. After cooling, the solvent was removed, and the crude product was recrystallized to obtain a white solid M(Br).

[0090] (b)ITO / PTAA / Cs 0.05 FA 0.81 MA 0.14 PbI 2.55 Br 0.45 / M(Br) / C 60 Fabrication of / BCP / Ag perovskite solar cells

[0091] Step 1: Preparation of the precursor solution:

[0092] Weigh 1 mg of PTAA, dissolve it in 1 mL of toluene and stir overnight to obtain a hole transport precursor solution.

[0093] Formulating Cs 0.05 FA 0.81 MA 0.14 PbI 2.55 Br 0.45 Perovskite precursor solution. Lead iodide (PbI₂) 575.3 mg, lead bromide (PbBr₂) 86.9 mg, methyl bromide (MABr) 23.1 mg, formamidinium iodide (FAI) 206.8 mg, and cesium iodide (CsI) 19.8 mg were dissolved in 1 mL of a mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) at a volume ratio of 90:10 to obtain a perovskite precursor solution. This solution was then stirred overnight on a hot plate at room temperature.

[0094] Weigh 0.5 mg of M(Br) and dissolve it in 1 mL of TFE, stirring overnight to obtain an M(Br) solution.

[0095] Step 2: Preparation of ITO / HTL thin films

[0096] The ITO transparent substrate was sequentially ultrasonically cleaned with deionized water, acetone, ethanol, and isopropanol for 20 minutes, dried with nitrogen, and then treated with ozone plasma for 15 minutes. The substrate was then placed in a nitrogen glove box for device fabrication. First, 30 μL of a toluene solution of PTAA was spin-coated onto the ITO substrate at 4000 rpm for 30 seconds. After spin-coating, the substrate was annealed at 95°C for 5 minutes to obtain a dense hole transport layer film with a thickness of 12 nm.

[0097] Step 3: Preparation of the perovskite active layer

[0098] Next, a perovskite precursor solution was spin-coated onto the ITO / PTAA film using an anti-solvent method. First, 60 μL of DMF solution was spin-coated at 5000 rpm for 20 s to increase the wettability of PTAA. Then, 60 μL of Cs was spin-coated. 0.05 FA 0.81 MA 0.14 PbI 2.55 Br 0.45 The solution was spin-coated at 5000 rpm for 28 seconds. 140 μL of the antisolvent toluene was slowly added dropwise 3 seconds before the end of the spin-coating. After spin-coating, the solution was annealed on a 95°C hot plate for 10 minutes to obtain a dense perovskite active layer with a thickness of 300 nm.

[0099] Step 4: Preparation of the interface modification layer

[0100] Subsequently, an interface modification layer was spin-coated. 50 μL of a TFE solution of M(Br) was spin-coated onto the perovskite film at a speed of 5000 rpm for 50 s, and the thickness of the interface modification layer was 3 nm.

[0101] Step 5: Evaporation of C 60 Electron transport layer, vapor-deposited copper bath

[0102] Next, an electron transport layer C with a thickness of approximately 25 nm was sequentially deposited in a vacuum evaporation apparatus. 60 The 7nm electrode modification layer, copper bath copper (BCP), has a lower efficiency than 1×10⁻⁶. -5 Under a vacuum of Pa, C 60 After being heated The vapor is slowly deposited onto the film obtained in step four to form a dense layer of a certain thickness, followed by the deposition of a layer of bath copper (BCP).

[0103] Step 6: Deposit metal electrodes

[0104] The vacuum chamber pressure during vapor deposition is maintained at less than 1 × 10⁻⁶. -4 Pa, with A 90 nm Ag electrode was deposited at a rate of [missing information].

[0105] Example 3

[0106] Preparation of ITO / PTAA / Cs 0.05 FA 0.81 MA 0.14 PbI 2.55 Br 0.45 / M(I) / C 60 / BCP / Ag perovskite solar cells.

[0107] (a) Synthesis of interface modification material M(I)

[0108] A mixed solvent of 5 mL dichloromethane and 5 mL iodomethane was added to a 50 mL two-necked flask, followed by the addition of 5 mL methylaminoacrylic acid under an inert atmosphere. The reaction mixture was heated under reflux at 80 °C for 12 h. After cooling, the solvent was removed, and the crude product was recrystallized to obtain a white solid M(I).

[0109] (b)ITO / PTAA / Cs 0.05 FA 0.81 MA 0.14 PbI 2.55 Br 0.45 / M(I) / C 60 Fabrication of / BCP / Ag perovskite solar cells

[0110] Step 1: Preparation of the precursor solution:

[0111] Weigh 2 mg of PTAA, dissolve it in 1 mL of toluene and stir overnight to obtain a hole transport precursor solution.

[0112] Formulating Cs 0.05 FA 0.81 MA 0.14 PbI 2.55 Br 0.45 Perovskite precursor solution. 523 mg of lead iodide (PbI₂), 79 mg of lead bromide (PbBr₂), 21 mg of methyl bromide (MABr), 188 mg of formamidine iodide (FAI), and 18 mg of cesium iodide (CsI) were dissolved in 1 mL of a mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) at a volume ratio of 95:5 to obtain a perovskite precursor solution. This solution was then placed on a hot plate at room temperature and stirred overnight.

[0113] Weigh 0.1 mg of M(I) and dissolve it in 1 mL of TFE and stir overnight to obtain an M(I) solution.

[0114] Step 2: Preparation of ITO / HTL thin films

[0115] The ITO transparent substrate was sequentially ultrasonically cleaned with deionized water, acetone, ethanol, and isopropanol for 20 minutes, dried with nitrogen, and then treated with ozone plasma for 15 minutes. The substrate was then placed in a nitrogen glove box for device fabrication. First, 30 μL of a toluene solution of PTAA was spin-coated onto the ITO substrate at 5000 rpm for 30 seconds. After spin-coating, the substrate was annealed at 100°C for 5 minutes to obtain a dense hole transport layer film with a thickness of 10 nm.

[0116] Step 3: Preparation of the perovskite active layer

[0117] Next, a perovskite precursor solution was spin-coated onto the ITO / PTAA film using an anti-solvent method. First, 60 μL of DMF solution was spin-coated at 5000 rpm for 20 s to increase the wettability of PTAA. Then, 60 μL of Cs was spin-coated. 0.05 FA 0.81 MA 0.14 PbI 2.55 Br 0.45 The solution was spin-coated at 4000 rpm for 28 seconds. 130 μL of the antisolvent toluene was slowly added 3 seconds before the end of the spin-coating process. After spin-coating, the solution was annealed on a hot plate at 100 °C for 10 minutes to obtain a dense perovskite active layer with a thickness of 320 nm.

[0118] Step 4: Preparation of the interface modification layer

[0119] Subsequently, an interface modification layer was spin-coated. 50 μL of a TFE solution of M(I) was spin-coated onto the perovskite film at a speed of 6000 rpm for 50 s, and the thickness of the interface modification layer was 2 nm.

[0120] Step 5: Evaporation of C 60 Electron transport layer, vapor-deposited copper bath

[0121] Next, an electron transport layer C with a thickness of approximately 30 nm was sequentially deposited in a vacuum evaporation apparatus. 60 A 6nm electrode modification layer, copper bath copper (BCP), at a concentration below 1×10⁻⁶. -5 Under a vacuum of Pa, C 60 After being heated The vapor is slowly deposited onto the film obtained in step four to form a dense layer of a certain thickness, followed by the deposition of a layer of bath copper (BCP).

[0122] Step 6: Deposit metal electrodes

[0123] The vacuum chamber pressure during vapor deposition is maintained at less than 1 × 10⁻⁶. -4 Pa, with An 80 nm Ag electrode was deposited at a rate of [missing information].

[0124] Comparative Example 1

[0125] Preparation of ITO / PTAA / Cs 0.05 FA 0.81 MA 0.14 PbI 2.55 Br 0.45 / C 60 / BCP / Ag perovskite solar cells:

[0126] Weigh 2 mg of PTAA and dissolve it in 1 mL of toluene, stirring overnight. Prepare Cs. 0.05 FA 0.81 MA 0.14 PbI 2.55 Br 0.45 Perovskite precursor solution. 523 mg of lead iodide (PbI₂), 79 mg of lead bromide (PbBr₂), 21 mg of methyl bromide (MABr), 188 mg of formamidine iodide (FAI), and 18 mg of cesium iodide (CsI) were dissolved in 1 mL of a mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) at a volume ratio of 95:5 to obtain the perovskite precursor solution. This solution was then stirred overnight on a hot plate at room temperature. An ITO transparent substrate was sequentially ultrasonically cleaned with deionized water, acetone, ethanol, and isopropanol for 20 minutes each, dried with nitrogen, and then treated with ozone plasma for 15 minutes. The substrate was then placed in a nitrogen glove box for device fabrication. First, a 30 μL solution of PTAA in toluene was spin-coated onto an ITO substrate at 5000 rpm for 30 s. After spin-coating, the substrate was annealed at 100°C for 5 minutes to obtain a dense hole transport layer film. Next, a perovskite precursor solution was spin-coated onto the ITO / PTAA film using an anti-solvent method. First, 60 μL of DMF solution was spin-coated at 5000 rpm for 20 s to increase the wettability of PTAA. Then, 60 μL of Cs was spin-coated. 0.05 FA 0.81 MA 0.14 PbI 2.55 Br 0.45 The solution was spin-coated at 4000 rpm for 28 seconds. Three seconds before the end of the spin-coating process, 130 μL of the anti-solvent toluene was slowly added dropwise. After spin-coating, the solution was annealed at 100°C for 10 minutes to obtain a dense perovskite active layer. This was then transferred to a vacuum evaporator to sequentially deposit an electron transport layer C with a thickness of approximately 30 nm. 60 The electrode is modified with a 6nm copper bath (BCP) layer and an 80nm Ag electrode.

[0127] After the device was fabricated, the photoelectric conversion efficiency was measured. The device efficiency obtained in Example 3 was 20.4%; the photoelectric conversion efficiency of the device obtained in Comparative Example 1 was 18.8%. Figure 1 As shown. The photoelectric conversion efficiency of the device in Comparative Example 1 is 18.8%, which is significantly lower than the efficiency of the device modified with M(X) in this invention. The charge carrier transport and recombination characteristics of the device were investigated using electrochemical impedance spectroscopy. Figure 2 Data shows that after M(I) interface modification (Example 3), the transfer resistance is smaller, indicating that the device provided by the present invention has good charge transfer and low recombination; finally, the unencapsulated device was placed in a hole with a humidity of 40% to 50% to test the humidity stability of the device. Figure 3 The device modified based on the M(I) interface (Example 3) can still maintain 80% of its initial efficiency after 1700 hours, i.e., T 80 =1700h, therefore, the perovskite solar cells prepared based on the M(I) interface modification layer pave the way for commercial development.

[0128] The above detailed description further illustrates the purpose, technical solution, and beneficial effects of the invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An application of an ammonium halide salt in perovskite solar cells, wherein the general structural formula of the ammonium halide salt is: in, R is one of ethyl methacrylate or ethyl methacrylate; X is a halogen.

2. The application according to claim 1, characterized in that, In the general structural formula of the haloammonium salt: X is selected from Cl, Br, and I.

3. The application according to claim 1 or 2, characterized in that, The method for preparing the haloammonium salt includes: dissolving a haloalkane in a solvent, adding an amine compound, and heating to react to obtain the haloammonium salt.

4. The application according to claim 3, characterized in that, The haloalkane mentioned is selected from haloalkane with 1 carbon atom; and / or, The amino compound is selected from at least one of dimethylaminoethyl methacrylate and dimethylaminoethyl ethyl ethyl acrylate; and / or, The molar ratio of the haloalkane to the amino compound is 1.5:1 to 10:1; and / or, The solvent is selected from organic solvents; and / or, The volume ratio of the haloalkane to the solvent is 1:0.1 to 1:10; and / or, The heating reaction temperature is 40~100 ℃, and the heating reaction time is 5~24 h; and / or, The heating reaction is carried out in an inert atmosphere; and / or, The ammonium halide obtained from the heating reaction needs to be recrystallized.

5. The application according to claim 4, characterized in that, The haloalkane is selected from at least one of iodomethane, chloromethane, and bromomethane; and / or, The molar ratio of the haloalkane to the amino compound is 2.5:1 to 6:1; and / or, The solvent is selected from at least one of dichloromethane, diethyl ether, and tetrahydrofuran; and / or, The volume ratio of the haloalkane to the solvent is 1:1 to 1:5; and / or, The heating reaction temperature is 45~80 ℃, and the heating reaction time is 12~16 h.

6. A perovskite solar cell comprising the ammonium halide salt as described in any one of claims 1 to 5.

7. The perovskite solar cell according to claim 6, characterized in that, The perovskite solar cell comprises, in sequence: a cathode substrate, a hole transport layer, a photoactive layer, an interface modification layer containing the ammonium halide salt, an electron transport layer, and a metal anode.

8. The perovskite solar cell according to claim 7, characterized in that, The cathode substrate is ITO glass; and / or, The hole transport layer is a poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] layer; and / or, The thickness of the hole transport layer is 5 ~ 20 nm; and / or, The photoactive layer is a perovskite photoactive layer; and / or, The thickness of the photoactive layer is 200 ~ 500 nm; and / or, The thickness of the interface modification layer is 1 ~ 10 nm; and / or, The electron transport layer includes C 60 Electron transport layer and copper bath layer; and / or, The metal anode is selected from at least one of Ag and Cu; and / or, The thickness of the metal anode is 50 ~ 200 nm.

9. The perovskite solar cell according to claim 8, characterized in that, The hole transport layer has a thickness of 10~15 nm; and / or, The thickness of the photoactive layer is 300 ~ 400 nm; and / or, The thickness of the interface modification layer is 2 to 5 nm; and / or, The C 60 The electron transport layer has a thickness of 10-50 nm, and the copper bath has a thickness of 5-10 nm; and / or, The thickness of the metal anode is 80 ~ 100 nm.

10. The perovskite solar cell according to claim 9, characterized in that, The C 60 The thickness of the electron transport layer is 20-30 nm, and the thickness of the copper bath is 6-8 nm.

11. A method for preparing a perovskite solar cell according to any one of claims 6 to 10, comprising preparing an interface modification layer containing the ammonium halide salt, depositing an electron transport layer and a metal electrode by vapor deposition, thereby obtaining the perovskite solar cell.

12. The preparation method according to claim 11, characterized in that, The preparation method specifically includes the following steps: Step 1: Preparation of the precursor solution: (a) Add poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] powder to an organic solvent and stir to obtain a hole transport precursor solution; (b) Dissolve lead iodide, lead bromide, methyl bromide, formamidine iodide and cesium iodide in a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide to obtain a perovskite precursor solution; (c) Dissolve the haloammonium salt in an organic solvent to obtain a haloammonium salt solution; Step 2: Spin-coat the hole transport precursor solution onto indium tin oxide, and anneal to obtain an ITO / HTL thin film coated with a hole transport layer. Step 3: Spin-coat the perovskite precursor solution onto the ITO / HTL film obtained in Step 2, and dry it to obtain an ITO / HTL / perovskite film coated with a perovskite photoactive layer. Step 4: Spin-coat the ITO / HTL / perovskite film obtained in Step 3 with a halide ammonium salt solution to obtain an ITO / HTL / perovskite film with an interface modification layer. Step 5: Evaporation of C 60 Electron transport layer, vapor-deposited copper bath; Step 6: Evaporate metal electrodes.

13. The preparation method according to claim 12, characterized in that, In step one: The concentration of the hole transport precursor solution is 0.1 ~ 5 mg / mL; and / or, In terms of volume percentage, the dimethyl sulfoxide in step b accounts for 1 to 20% of the total volume of the mixed solvent; and / or, In the perovskite precursor solution, based on 1 mL of mixed solvent, the content of lead iodide is 400-700 mg, lead bromide is 60-120 mg, methyl bromide is 5-50 mg, formamidinium iodide is 100-250 mg, and cesium iodide is 5-30 mg; and / or, The concentration of the haloammonium salt solution is 0.1 ~ 5.0 mg / mL.

14. The preparation method according to claim 13, characterized in that, In step one: The concentration of the hole transport precursor solution is 0.5 ~ 2.0 mg / mL; and / or, In terms of volume percentage, the dimethyl sulfoxide in step b accounts for 5-10% of the total volume of the mixed solvent; and / or, In the perovskite precursor solution, based on 1 mL of mixed solvent, the content of lead iodide is 450-600 mg, lead bromide is 70-100 mg, methyl bromide is 10-30 mg, formamidinium iodide is 150-210 mg, and cesium iodide is 10-20 mg; and / or, The concentration of the haloammonium salt solution is 0.1 ~ 1.0 mg / mL.

15. The preparation method according to claim 12, characterized in that, The annealing temperature in step two is 65~120℃, and the annealing time is 5~20 min; and / or, The drying temperature in step three is 80 ~ 150 ℃.

16. The preparation method according to claim 15, characterized in that, The annealing temperature is 80~100℃, and the annealing time is 5~10 min; and / or, The drying temperature in step three is 90 ~ 120 ℃.

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