A multidentate ligand-modified perovskite solar cell and a method for preparing the same

Abstract

The present invention belongs to the technical field of perovskite cells, and specifically relates to a multidentate ligand-modified perovskite solar cell and a preparation method thereof. In the preparation method provided by the present invention, when the perovskite active layer is prepared, a pyridine multidentate ligand additive is added to the perovskite film when the film is in a semi-crystalline state. On the one hand, different passivation functional groups such as amino groups, halogen atoms, pyridine, etc. in such additives can passivate different types of defects through chelation anchoring. On the other hand, the additive penetrates into the semi-crystalline perovskite film and is distributed on the film surface and grain boundaries, etc., which can simultaneously achieve the effect of passivating defects in bulk phase grains, grain boundaries and interfaces. At the same time, the interaction between the perovskite lattice and the additive molecules can also regulate the crystallization process to form a high-quality film. Finally, the defect state density is reduced, the non-radiative energy loss is reduced, and the photoelectric conversion efficiency and stability of the perovskite solar cell device are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of solar cells, and in particular relates to a multidentate ligand-modified perovskite solar cell and a preparation method thereof. Background Art

[0002] As a new type of green energy generation technology, metal halide perovskite solar cells have attracted widespread attention due to their high photoelectric conversion efficiency, large-area processing by solution method, and the ability to be combined with silicon solar cells to prepare stacked solar cells. As a research hotspot in the field of solar power generation, the photoelectric conversion efficiency of perovskite solar cells has increased from the initial 3.8% to 25.7% in just over a decade, and their application prospects are broad.

[0003] At present, the widely used perovskite polycrystalline ionic crystal films are mostly prepared based on solution processing technology, which will inevitably produce high-density defects during the crystallization of the film. These defects may exist in the bulk grains, grain boundaries and interfaces, including vacancy defects, antisite defects, interstitial defects, impurity defects, extension defects, etc. Various types of defects are the main reason for serious non-radiative recombination inside the device, which in turn limits the improvement of the photovoltaic properties and stability of solar cell devices.

[0004] The passivation defect strategy has been proven to be an effective strategy to improve the optoelectronic performance and stability of halide perovskites. However, due to the large number of defect types and the types of defect sites, there is an urgent need for an efficient passivation strategy that can simultaneously passivate different defect sites and multiple defect types, reduce the defect state density, and reduce non-radiative energy loss, thereby improving the optoelectronic properties and stability of perovskite solar cells. At the same time, most of the existing processes perform passivation after the perovskite layer is prepared, without considering the problem of minimizing defect formation during the preparation process. Summary of the invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the above-mentioned defects in the prior art, thereby providing a multidentate ligand-modified perovskite solar cell and a preparation method thereof.

[0006] To this end, the present invention provides the following technical solutions:

[0007] The present invention provides a multidentate ligand-modified perovskite solar cell, comprising a perovskite active layer. During the preparation of the perovskite active layer, a pyridine multidentate ligand additive is added into the perovskite film when the perovskite film is in a semi-crystalline state.

[0008] Optionally, the pyridine multidentate ligand additive is one of 5-aminomethyl-2-fluoropyridine, 5-aminomethyl-2-chloropyridine and 5-aminomethyl-2-bromopyridine.

[0009] Optionally, it includes a transparent conductive substrate layer, an electron transport layer, a perovskite active layer, a hole transport layer and a metal back electrode which are arranged in sequence.

[0010] The present invention also provides a method for preparing the above-mentioned perovskite solar cell, comprising the following steps: sequentially preparing an electron transport layer, a perovskite active layer, a hole transport layer and a metal back electrode on the surface of a transparent conductive substrate layer;

[0011] Wherein, the preparation method of the perovskite active layer comprises:

[0012] The perovskite precursor solution is coated on the surface of the electron transport layer, the substrate is rotated, and the anti-solvent is added dropwise to infiltrate the semi-crystalline perovskite film with an additive solution containing a pyridine multidentate ligand. After the rotation stops, annealing is performed to obtain a perovskite active layer.

[0013] Optionally, in the method for preparing the perovskite active layer, the time for infiltrating the additive solution is any moment between 1 second and 10 seconds after the anti-solvent is added dropwise.

[0014] Optionally, in the additive solution containing the pyridine multidentate ligand, the concentration of the pyridine multidentate ligand is 0.1 mg / mL to 5 mg / mL.

[0015] Optionally, in the additive solution containing the pyridine multidentate ligand, the solvent is selected from at least one of isopropanol, chlorobenzene, ethanol and ethyl acetate.

[0016] Optionally, when the additive solution containing the pyridine multidentate ligand is infiltrated, the amount of the additive solution used on each substrate (size 2 cm×2 cm) is 10 μL to 1000 μL.

[0017] Optionally, the annealing is performed in an air environment, with an annealing temperature of 80° C. to 150° C. and an annealing time of 10 min to 50 min.

[0018] Optionally, the thickness of the perovskite active layer is 300nm to 1500nm.

[0019] Typically, but not limiting, the method for preparing the multidentate ligand-modified perovskite solar cell provided by the present invention comprises the following specific steps:

[0020] Step 1: The FTO glass substrate is cleaned with deionized water, acetone, and isopropanol ultrasonically in sequence, and the solvent remaining on the glass substrate is blown dry with a nitrogen stream to obtain a clean transparent conductive substrate;

[0021] Step 2: Place the conductive substrate cleaned in step 1 on a UVO coating machine after treatment, use a pipette to absorb the tin dioxide nanocrystal solution, and evenly apply it on the surface of the substrate. Start the coating machine to rotate at high speed. After the rotation stops, place the substrate on a hot stage and anneal in air to obtain an electron transport layer.

[0022] Step 3: After UVO treatment, place the substrate in step 2 on a coater in a glove box, use a pipette to absorb the prepared perovskite precursor solution, evenly apply it on the surface of the substrate, start the coater to rotate at high speed, drip the anti-solvent and infiltrate the additive solution into the semi-crystalline perovskite film, and after the rotation stops, place it on a hot stage in an air environment for annealing to obtain a perovskite active layer;

[0023] Step 4: Place the substrate in step 3 on a coating machine in a glove box, use a pipette to absorb the prepared hole transport layer solution, evenly apply it on the surface of the substrate, start the coating machine to rotate at high speed, and after the rotation stops, place the substrate in a dry air environment to oxidize and obtain a hole transport layer;

[0024] Step 5: Prepare a metal back electrode on the hole transport layer by thermal evaporation on the substrate in step 4.

[0025] Furthermore, the ultrasonic cleaning time using each solvent in step 1 is 15 minutes to 30 minutes.

[0026] Furthermore, in step 2, the rotation speed of the coating machine is 3000 rpm to 8000 rpm, the rotation time is 30s to 60s, the hot stage annealing temperature is 100° C. to 150° C., and the annealing time is 30min to 60min.

[0027] Furthermore, in step 3, the volume of the precursor solution sucked by the pipette is 20μL~100μL, the speed of the gel spinner is 2000rpm~8000rpm, the rotation time is 30s~100s, the volume of the anti-solvent sucked by the pipette is 300μL~3000μL, the hot stage annealing temperature is 80℃~160℃, and the annealing time is 10min~50min.

[0028] Furthermore, in step 3, the anti-solvent is one or more of chlorobenzene, ether, acetone, toluene, ethyl acetate and chloroform.

[0029] Furthermore, in step 4, the volume of the hole transport layer solution sucked by the pipette is 30 μL to 80 μL, the rotation speed of the gelator is 3000 rpm to 8000 rpm, the rotation time is 30s to 60s, and the oxidation time is 12h to 24h.

[0030] Furthermore, during the evaporation in step 5, the pressure in the evaporation chamber is 9×10 -5Pa, the thickness of molybdenum oxide is 8nm, and the thickness of the metal Ag electrode is 80nm~120nm.

[0031] The technical solution of the present invention has the following advantages:

[0032] The multidentate ligand-modified perovskite solar cell provided by the present invention has a pyridine multidentate ligand additive infiltrated into the perovskite active layer. On the one hand, different passivation functional groups such as amino, halogen atoms, pyridine, etc. in such additives can passivate different types of defects through chelation anchoring. On the other hand, such additives penetrate into the perovskite active layer and are distributed on the film surface and grain boundaries, etc. at the same time, which can simultaneously achieve the effect of passivating defects in bulk phase grains, grain boundaries and interfaces. Reduce non-radiative energy loss and improve the photoelectric conversion efficiency and stability of perovskite solar cell devices.

[0033] The method for preparing a multidentate ligand-modified perovskite solar cell provided by the present invention comprises the following steps: sequentially forming an electron transport layer, a perovskite active layer, a hole transport layer and an electrode layer on the surface of a transparent conductive substrate to obtain a perovskite solar cell; when preparing the perovskite active layer, adding a pyridine multidentate ligand additive to the perovskite film when the perovskite film is in a semi-crystalline state.

[0034] By infiltrating this type of additive into a semi-crystalline perovskite film, the interaction between the perovskite lattice and the additive molecules can also regulate the crystallization process to form a high-quality film, ultimately fundamentally reducing the defect state density, reducing non-radiative energy loss, and improving the photoelectric conversion efficiency and stability of perovskite solar cell devices.

[0035] In addition, the preparation method provided by the present invention has simple process, mild conditions, easy control, and broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0037] Figure 1 It is a schematic diagram of the structure of the perovskite solar cell provided by the present invention;

[0038] Figure 2 is a JV curve diagram of the perovskite solar cell provided by Example 1 of the present invention and Comparative Examples 1, 2 and 3;

[0039] Figure 31 is a JV curve diagram of the perovskite solar cells of Examples 1, 2 and 3 of the present invention;

[0040] Figure 4 is a JV curve diagram of the perovskite solar cells of Examples 1, 4, 5 and 6 of the present invention;

[0041] Figure 5 is a graph showing the relationship between the normalized energy conversion efficiency of the perovskite solar cells of Example 1 of the present invention and Comparative Examples 1, 2, and 3 as a function of time;

[0042] Reference numerals:

[0043] 1. Transparent conductive substrate layer; 2. Electron transport layer; 3. Perovskite active layer; 4. Hole transport layer; 5. Metal back electrode. DETAILED DESCRIPTION

[0044] The following examples are provided for a better understanding of the present invention, but are not intended to limit the best mode of implementation, nor to limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior arts shall fall within the protection scope of the present invention.

[0045] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in the field can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be obtained commercially.

[0046] The present invention provides a multi-dentate ligand modified perovskite solar cell, the structural schematic diagram of which is as follows: Figure 1 As shown, it includes a transparent conductive substrate layer 1, an electron transport layer 2, a perovskite active layer 3, a hole transport layer 4 and a metal back electrode 5 which are arranged in sequence.

[0047] In particular, the perovskite active layer is obtained by infiltrating pyridine multidentate ligands into a semi-crystalline perovskite film during the preparation process.

[0048] The method for preparing a multidentate ligand-modified perovskite solar cell provided by the present invention comprises the following steps:

[0049] An electron transport layer, a perovskite active layer, a hole transport layer and a metal back electrode are sequentially formed on the surface of a transparent conductive substrate to obtain a perovskite solar cell.

[0050] In the present invention, the transparent conductive substrate is preferably ITO glass, FTO glass, AZO glass or conductive PET, more preferably FTO glass. The present invention has no special restrictions on the source of the transparent conductive substrate, and commercially available products known to those skilled in the art can be used. In the present invention, the transparent conductive substrate is preferably washed with deionized water, acetone, and isopropanol for 15 to 30 minutes each before use, and blown dry with a nitrogen gun.

[0051] In the present invention, the electron transport layer is preferably SnO2, TiO x 、NiO x , CuO x , CuSCN, CuPc or C 60 and its derivatives, more preferably SnO2. The thickness of the electron transport layer is preferably 10nm to 200nm, more preferably 20nm to 100nm. The present invention has no special restrictions on the method for forming the electron transport layer on the conductive substrate, and the preparation method of the electron transport layer well known to those skilled in the art can be used.

[0052] In the present invention, the perovskite precursor solution film preferably has an ABX3 type crystal structure, wherein A is an organic cation and / or an inorganic cation, B is a divalent positive metal ion, and X is one or more of I, Br and Cl. In the present invention, the organic cation and / or inorganic cation is preferably one or more of Cs, FA, and MA, and the divalent positive metal ion is preferably Pb 2+ or Sn 2+ , X is preferably one or more of I and Br. More preferably, in the present invention, the perovskite precursor solution film crystal structure is FA 0.95 MA 0.05 Pb(I 0.95 Br 0.05 )3. The solvent of the perovskite precursor solution is preferably one or more of DMF and DMSO. More preferably, the solvent of the perovskite precursor solution is a mixed solvent of DMF and DMSO, and the volume ratio DMF:DMSO=4:1. The concentration of the perovskite precursor solution is preferably 1mg / mL to 2mg / mL. More preferably, the concentration of the perovskite precursor solution is 1.4mg / mL. On this basis, a perovskite precursor solution that is well known to those skilled in the art and capable of forming a thin film of the perovskite precursor solution can be used, and those skilled in the art have no special restrictions on the preparation method of the perovskite precursor solution.

[0053] In the present invention, the pyridine multidentate ligand additive used in the preparation process of the perovskite active layer is preferably one of 5-aminomethyl-2-fluoropyridine, 5-aminomethyl-2-chloropyridine, and 5-aminomethyl-2-bromopyridine, and more preferably, the additive is 5-aminomethyl-2-chloropyridine. The solvent of the additive is preferably one of isopropanol (IPA), ethanol, and ethyl acetate, and more preferably, the solvent of the additive is IPA. The concentration of the additive solution is preferably 0.1 to 5 mg / mL, and more preferably, the concentration of the additive solution is 0.5 to 2 mg / mL.

[0054] In the present invention, the preparation method of the additive solution used in the preparation process of the perovskite active layer is preferably: dissolving the additive in a solvent, stirring at room temperature until completely dissolved, and filtering out impurities in the mixed solution with a polytetrafluoroethylene filter (0.22 μm) to obtain a pure additive solution.

[0055] In the present invention, the anti-solvent used in the preparation process of the perovskite active layer is preferably one or more selected from chlorobenzene, diethyl ether, acetone, toluene, ethyl acetate and chloroform, more preferably chlorobenzene or diethyl ether.

[0056] In the present invention, the preparation method of the perovskite active layer is preferably a one-step spin coating method, and the preparation process is preferably as follows: the substrate (2cm×2cm) is subjected to UVO treatment for 5min to 20min and then placed on a coater in a glove box, 20μL to 100μL of the prepared perovskite precursor solution is drawn using a pipette, and evenly coated on the surface of the substrate, the coater is started to rotate at high speed, the rotation speed is 2000rpm to 8000rpm, the rotation time is 30 to 100s, 300μL to 3000μL of anti-solvent is added at 10 to 50s after the start of rotation, and 10μL to 1000μL of additive solution is quickly added at any moment between 1 and 10s after the anti-solvent addition is completed. After the rotation stops, it is placed on a hot stage in an air environment for annealing, the annealing temperature is 80°C to 160°C, the annealing time is 10min to 50min, and the air humidity is 20% to 50%. After the annealing is completed, the perovskite active layer is obtained.

[0057] More preferably:

[0058] After UVO treatment of the substrate for 10 minutes, place it on a coater in a glove box, use a pipette to absorb 30μL~60μL of the prepared perovskite active layer precursor solution, evenly apply it on the surface of the substrate, start the coater to rotate at high speed, the rotation speed is 3000rpm~8000rpm, the rotation time is 60~90s, add anti-solvent at 25~40s after the start of rotation, and quickly add 20μL~100μL of additive solution at any moment between 2~6s after the anti-solvent addition is completed. After the rotation stops, place it on a hot stage for annealing in an air environment, the annealing temperature is 100℃~150℃, the annealing time is 10min~30min, and the air humidity is 30%~40%. After annealing, a perovskite active layer is obtained.

[0059] In the present invention, the thickness of the perovskite active layer is preferably 100 nm to 2000 nm, more preferably 300 nm to 1500 nm.

[0060] In the present invention, the hole transport layer is preferably Spiro OMeTAD, P3HT, PTAA, MnO x , WO x or 2PACz layer, more preferably a Spiro OMeTAD layer; the thickness of the hole transport layer is preferably 20nm to 400nm, more preferably 100nm to 200nm. The present invention has no special restrictions on the method for forming the hole transport layer on the perovskite active layer, and the preparation method of the hole transport layer well known to those skilled in the art can be used.

[0061] The present invention has no special restrictions on the type and formation method of the metal back electrode, and a technical solution for forming a metal back electrode on a hole transport layer that is well known to those skilled in the art can be used. In a preferred embodiment of the present invention, the hole transport layer is transferred to a thermal evaporation device, and the vacuum degree reaches 1×10 -5 Under the condition of Pa, 8nm molybdenum oxide is first evaporated, and then the electrode (Ag) is evaporated with a thickness of 100nm; after the evaporation is completed, the perovskite solar cell is obtained.

[0062] The present invention provides a method for preparing a multi-dentate ligand-modified perovskite solar cell, comprising the following steps: sequentially forming an electron transport layer, a perovskite active layer, a hole transport layer and a counter electrode on the surface of a transparent conductive substrate to obtain a perovskite solar cell. Compared with the prior art, the preparation method provided by the present invention adds a pyridine multi-dentate ligand additive to the perovskite film when the perovskite active layer is prepared when the perovskite film is in a semi-crystalline state. The present invention has the following beneficial technical effects: on the one hand, different passivation functional groups such as amino groups, halogen atoms, pyridine, etc. in such additives can passivate different types of defects through chelation anchoring. On the other hand, the additive penetrates into the semi-crystalline perovskite film and is distributed on the film surface and grain boundaries, etc., which can simultaneously achieve the effect of passivating bulk phase grains, grain boundaries and interfaces. At the same time, the interaction between the perovskite lattice and the additive molecules can also regulate the crystallization process to form a high-quality film. Finally, the defect state density is reduced, the non-radiative energy loss is reduced, and the photoelectric conversion efficiency and stability of the perovskite solar cell device are improved.

[0063] In addition, the preparation method provided by the present invention has simple process, mild conditions, easy control, and broad application prospects.

[0064] In order to further illustrate the present invention, the following examples are provided for detailed description.

[0065] Example 1

[0066] This embodiment provides a multidentate ligand-modified perovskite solar cell, the composition and specific preparation method of which are as follows:

[0067] Step 1: Place FTO transparent conductive glass (2cm×2cm) in deionized water, acetone, and isopropanol and ultrasonically clean for 15 minutes each twice, blow dry with nitrogen, and store for later use.

[0068] Step 2: Dilute the tin dioxide (SnO2) stock solution and ultrapure water in a volume ratio of 1:5, and stir thoroughly to obtain a SnO2 precursor solution; place the FTO substrate in a UV ozone cleaner for 10 minutes; take 50μL of SnO2 precursor solution and evenly spread it on the surface of the FTO conductive glass, and set the parameters of the coating machine to a speed of 3000rpm / s and a time of 30s; then place it on a 150℃ hot stage in an air environment for annealing for 30 minutes to obtain a SnO2 film (30nm); place the above-prepared SnO2 film in a UV ozone cleaner for 20 minutes for subsequent spin coating.

[0069] Step 3: Place the substrate on the coating machine in the glove box and use a pipette to draw 50 μL of the prepared perovskite precursor solution (the perovskite formula is: FA 0.95 MA 0.05 Pb(I 0.95Br 0.05 )3, precursor concentration 1.4mol / L), evenly apply it on the substrate surface, start the high-speed rotation of the coating machine, the rotation speed is 6000rpm, the rotation time is 70s, 200μL chlorobenzene anti-solvent is quickly added at 30s after the start of rotation, and 60μL 5-aminomethyl-2-chloropyridine isopropanol solution (concentration 2mg / mL) is immediately added at 35s after the start of rotation. After the rotation stops, place it on a hot stage for annealing in an air environment, the annealing temperature is 100℃, the annealing time is 30min, and the air humidity is 40%. After annealing, a perovskite active layer (400nm) is obtained.

[0070] Step 4: Take 60 μL of Spiro OMeTAD solution (90 mg of spiro-OMeTAD, 23 μL of LiTFSI solution (520 mg of Li-TFSI was dissolved in 1 mL of acetonitrile), and 35 μL of 4-tert-butylpyridine was dissolved in 1 mL of chlorobenzene solvent) and spin-coated on the prepared perovskite film. The parameters of the coater were set to a speed of 5000 rpm / s and a time of 30 s. After spin coating, it was placed in dry air (25°C, 1% humidity) for oxidation for 12 hours to obtain a hole transport layer.

[0071] Step 5: Finally, use high vacuum evaporation equipment to evaporate, and the pressure in the evaporation chamber is 9×10 -5 Pa, first evaporate 8nm thick molybdenum oxide, and then evaporate 100nm thick metal Ag electrode to obtain a perovskite solar cell device.

[0072] Example 2

[0073] This embodiment provides a multidentate ligand-modified perovskite solar cell. Compared with Embodiment 1, the difference is that the concentration of the isopropanol solution of the additive 5-aminomethyl-2-chloropyridine in step 3 is 1 mg / mL.

[0074] Example 3

[0075] This embodiment provides a multidentate ligand-modified perovskite solar cell. Compared with Embodiment 1, the difference is that the concentration of the isopropanol solution of the additive 5-aminomethyl-2-chloropyridine in step 3 is 3 mg / mL.

[0076] Example 4

[0077] This embodiment provides a multidentate ligand-modified perovskite solar cell. Compared with Embodiment 1, the difference is that in step 3, 60 μL of 5-aminomethyl-2-chloropyridine isopropanol solution (concentration 2 mg / mL) is immediately added dropwise at 33 seconds after the start of rotation.

[0078] Example 5

[0079] This embodiment provides a multidentate ligand-modified perovskite solar cell. Compared with Embodiment 1, the difference is that in step 3, 60 μL of 5-aminomethyl-2-chloropyridine isopropanol solution (concentration 2 mg / mL) is immediately added dropwise at 40 seconds after the start of rotation.

[0080] Example 6

[0081] This embodiment provides a multidentate ligand-modified perovskite solar cell. Compared with Embodiment 1, the difference is that in step 3, 60 μL of 5-aminomethyl-2-bromopyridine isopropanol solution (concentration 2 mg / mL) is immediately added dropwise at 35 seconds after the start of rotation.

[0082] Comparative Example 1

[0083] This comparative example provides a perovskite solar cell, which is different from Example 1 in that when preparing the perovskite active layer in step 3, no additive material is added during the perovskite crystallization process.

[0084] Comparative Example 2

[0085] The present comparative example provides a multidentate ligand modified perovskite solar cell, which is different from Example 1 in that when preparing the perovskite active layer in step 3, the additive material is not added when the perovskite is in a semi-crystalline state, but after the perovskite active layer is completely crystallized, the additive material is spin-coated on the surface of the active layer to form an interface passivation layer. The specific preparation process of this step is as follows: a substrate is placed on a coater in a glove box, 50 μL of the prepared perovskite precursor solution is drawn with a pipette, and evenly coated on the surface of the substrate, the coater is started to rotate at a high speed of 6000 rpm and a rotation time of 70 s, 200 μL of chlorobenzene anti-solvent is added at 30 s after the rotation starts, and after the rotation stops, the perovskite is placed on a hot stage for annealing in an air environment, the annealing temperature is 100°C, the annealing time is 30 min, and the air humidity is 40%, and the perovskite active layer is obtained after the annealing is completed. The substrate was moved to a coater in a glove box and the coater was started to rotate at high speed, with a rotation speed of 6000 rpm and a rotation time of 30 s. 60 μL of 5-aminomethyl-2-chloropyridine isopropanol solution (concentration 2 mg / mL) was immediately added after the rotation started. After the rotation stopped, the substrate was placed on a hot stage for annealing at a temperature of 100°C and an annealing time of 10 min. After the annealing was completed, a perovskite active layer with an interface passivation layer formed on the surface was obtained.

[0086] Comparative Example 3

[0087] The present comparative example provides a perovskite solar cell, which is different from Example 1 in that when preparing the perovskite active layer in step 3, no additive material is added during the perovskite crystallization process, but the additive material is added when the perovskite precursor solution is prepared. The specific preparation process of this step is as follows: a substrate is placed on a coater in a glove box, 50 μL of a prepared perovskite active layer precursor solution (5-aminomethyl-2-chloropyridine concentration is 2 mg / mL) dissolved with 5-aminomethyl-2-chloropyridine is taken out with a pipette, and evenly coated on the surface of the substrate, the coater is started to rotate at a high speed of 6000 rpm and a rotation time of 70 s, 200 μL of chlorobenzene anti-solvent is added dropwise at 30 s after the rotation starts, and after the rotation stops, the substrate is placed on a hot stage for annealing in an air environment, the annealing temperature is 100° C., the annealing time is 30 min, and the air humidity is 40%, and the perovskite active layer is obtained after the annealing is completed.

[0088] Test Case

[0089] The performance of the perovskite solar cells provided in the embodiments of the present invention and the comparative examples was tested, and the specific testing method was as follows:

[0090] The current density voltage (JV) curves of the perovskite solar cells prepared in the PCE test examples and comparative examples were completed on a Kethley 2400 system under the following test conditions: the simulated light intensity was 100 mW cm -2 (AM 1.5G) scan rate 0.1V s -1 (step size is 0.02 V, time delay is 200 ms), the scanning interval is 1.2 V to -0.2 V, and the power output of the xenon lamp is calibrated by the KG5 standard Si battery of NERL (National Renewable Energy Laboratory) standard.

[0091] The stability test was carried out on unpackaged perovskite solar cell devices in a nitrogen glove box at room temperature.

[0092] The specific test results are shown in the table below:

[0093] Table 1

[0094]

[0095]

[0096] From the examples and comparative examples Figure 2-5As can be seen from the data in Table 1, when preparing the perovskite active layer, the present invention adds a pyridine multidentate ligand additive to the perovskite film when it is in a semi-crystalline state (Examples 1-6), and the perovskite solar cell device prepared is compared with the device without adding the additive (Comparative Example 1), the device that does not drop the additive material when the perovskite is in a semi-crystalline state, but spin-coats the additive material on the surface of the active layer to form an interface passivation layer after the perovskite active layer is completely crystallized (Comparative Example 2), and the device that does not drop the additive material during the perovskite crystallization process, but adds the additive material when the perovskite precursor solution is configured to achieve bulk doping (Comparative Example 3). The photoelectric characteristics such as open circuit voltage, short circuit current density, and filling factor are all improved. The perovskite solar cell device prepared by the method of the present invention has the advantages of high photoelectric conversion efficiency and strong stability.

[0097] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the scope of protection of the invention.

Claims

1. A multidentate ligand-modified perovskite solar cell, characterized in that: The invention comprises a perovskite active layer, and the preparation method of the perovskite active layer comprises: The perovskite precursor solution is applied to the surface of the electron transport layer, the substrate is rotated, an anti-solvent is added dropwise, an additive solution containing a pyridine multidentate ligand is infiltrated into the semi-crystalline perovskite film, and annealing is performed after the rotation is stopped to obtain a perovskite active layer; The pyridine multidentate ligand is one of 5-aminomethyl-2-fluoropyridine, 5-aminomethyl-2-chloropyridine and 5-aminomethyl-2-bromopyridine.

2. The multidentate ligand-modified perovskite solar cell according to claim 1, characterized in that: It includes a transparent conductive substrate layer, an electron transport layer, a perovskite active layer, a hole transport layer and a metal back electrode which are arranged in sequence.

3. A method for preparing a multidentate ligand-modified perovskite solar cell according to claim 2, characterized in that: The method comprises the following steps: sequentially preparing an electron transport layer, a perovskite active layer, a hole transport layer and a metal back electrode on the surface of a transparent conductive substrate layer; Wherein, the preparation method of the perovskite active layer comprises: The perovskite precursor solution is coated on the surface of the electron transport layer, the substrate is rotated, and the anti-solvent is added dropwise to infiltrate the semi-crystalline perovskite film with an additive solution containing a pyridine multidentate ligand. After the rotation stops, annealing is performed to obtain a perovskite active layer.

4. The method for preparing a multidentate ligand-modified perovskite solar cell according to claim 3, characterized in that: In the method for preparing the perovskite active layer, the time for infiltrating the additive solution is any time between 1 second and 10 seconds after the anti-solvent is added dropwise.

5. The method for preparing a multidentate ligand-modified perovskite solar cell according to claim 3, characterized in that: In the additive solution containing the pyridine multidentate ligand, the concentration of the pyridine multidentate ligand is 0.1 mg / mL to 5 mg / mL.

6. The method for preparing a multidentate ligand-modified perovskite solar cell according to claim 3, characterized in that: In the additive solution containing the pyridine multidentate ligand, the solvent is selected from at least one of isopropanol, chlorobenzene, ethanol and ethyl acetate.

7. The method for preparing a multidentate ligand-modified perovskite solar cell according to claim 3, characterized in that: When the additive solution containing the pyridine multidentate ligand is infiltrated, the amount of the additive solution used on each substrate with a size of 2 cm×2 cm is 10 μL to 1000 μL.

8. The method for preparing a multidentate ligand-modified perovskite solar cell according to claim 3, characterized in that: The annealing is carried out in an air environment, the annealing temperature is 80° C. to 150° C., and the annealing time is 10 min to 50 min.

9. The method for preparing a multidentate ligand-modified perovskite solar cell according to any one of claims 4 to 8, characterized in that: The thickness of the perovskite active layer is 300nm to 1500nm.

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