Perovskite solar cell and preparation method thereof

Abstract

This invention relates to the field of photovoltaic cell technology, specifically to a perovskite solar cell and its fabrication method. The fabrication method of the perovskite solar cell includes the following steps: fabricating a first carrier transport layer on one side of a transparent conductive electrode; fabricating a perovskite light-absorbing layer on the side of the first carrier transport layer facing away from the transparent conductive electrode; grinding and polishing the side of the perovskite light-absorbing layer facing away from the first carrier transport layer; fabricating a second carrier transport layer on the side of the perovskite light-absorbing layer facing away from the first carrier transport layer; and fabricating a metal electrode layer on the side of the second carrier transport layer facing away from the perovskite light-absorbing layer, thereby obtaining the perovskite solar cell. The perovskite solar cell fabrication method provided by this invention effectively reduces the surface undulation of the perovskite light-absorbing layer, enhances the adhesion between the second carrier transport layer and the perovskite light-absorbing layer, improves charge transport extraction efficiency, and enhances the photoelectric conversion efficiency and stability of the perovskite solar cell.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic cell technology, and in particular to a perovskite solar cell and its preparation method. Background Technology

[0002] The development of perovskite solar cells is booming, but there is still room for improvement in their photoelectric conversion efficiency and stability. The limiting factors are the harsh growth conditions of perovskite crystals, which are easily affected by annealing temperature, air humidity, and processing methods. This results in an uneven and non-uniform surface of the perovskite light-absorbing layer, resembling peaks and valleys. The surface undulation of the perovskite light-absorbing layer is nearly 100 nm, while the second carrier transport layer is generally less than 50 nm. This affects the adhesion between the second carrier transport layer and the perovskite light-absorbing layer. Uneven adhesion can even puncture the second carrier transport layer and the metal electrode layer, creating defect recombination centers that affect charge transport and induce water vapor infiltration, thereby reducing the photoelectric conversion efficiency and stability of perovskite solar cells. Summary of the Invention

[0003] This invention provides a method for fabricating perovskite solar cells, which can effectively reduce the surface undulation of the perovskite light-absorbing layer, enhance the adhesion between the second carrier transport layer and the perovskite light-absorbing layer, improve charge transport extraction efficiency, and improve the overall photoelectric conversion efficiency and stability of perovskite solar cells.

[0004] The present invention also provides a perovskite solar cell.

[0005] This invention provides a method for preparing a perovskite solar cell, comprising the following steps:

[0006] A first carrier transport layer is fabricated on one side of a transparent conductive electrode;

[0007] A perovskite light-absorbing layer is prepared on the side of the first carrier transport layer away from the transparent conductive electrode;

[0008] The side of the perovskite light-absorbing layer that is away from the first carrier transport layer is ground and polished.

[0009] A second charge carrier transport layer is prepared on the side of the perovskite light-absorbing layer opposite to the first charge carrier transport layer;

[0010] A metal electrode layer is fabricated on the side of the second carrier transport layer away from the perovskite light-absorbing layer to obtain the perovskite solar cell.

[0011] According to the method for fabricating perovskite solar cells provided by the present invention, by grinding and polishing the side of the perovskite light-absorbing layer away from the first carrier transport layer, the surface undulation of the perovskite light-absorbing layer can be effectively reduced, resulting in a smooth and uniform surface. Subsequently, a second carrier transport layer is fabricated on the side of the perovskite light-absorbing layer away from the first carrier transport layer. The second carrier transport layer is bonded to the smooth perovskite light-absorbing layer, enhancing the bonding between the second carrier transport layer and the perovskite light-absorbing layer, improving the charge transport extraction efficiency, and overall improving the photoelectric conversion efficiency and stability of the perovskite solar cell.

[0012] According to a method for fabricating a perovskite solar cell provided by the present invention, before the step of fabricating a first carrier transport layer on one side of a transparent conductive electrode, the method further includes:

[0013] The transparent conductive electrode is immersed in detergent for ultrasonic cleaning.

[0014] The transparent conductive electrode was sequentially immersed in deionized water, acetone, and isopropanol for ultrasonic cleaning.

[0015] According to a method for fabricating a perovskite solar cell provided by the present invention, before the step of ultrasonically cleaning the transparent conductive electrode by sequentially immersing it in deionized water, acetone, and isopropanol, the method further includes:

[0016] The transparent conductive electrode is immersed in deionized water to remove detergent.

[0017] According to a method for fabricating a perovskite solar cell provided by the present invention, the step of grinding and polishing the side of the perovskite light-absorbing layer away from the first carrier transport layer includes:

[0018] A polishing slurry is dropped onto the side of the perovskite light-absorbing layer that is away from the first carrier transport layer.

[0019] The perovskite light-absorbing layer on the side opposite to the first carrier transport layer is ground and polished using a grinding head.

[0020] According to a method for preparing a perovskite solar cell provided by the present invention, the polishing slurry is composed of abrasive and dispersion. The abrasive is one or a combination of diamond, alumina, silicon dioxide or silicon carbide; the dispersion is a mixture of isopropanol (95% by volume) and N,N-dimethylformamide (5% by volume).

[0021] According to a method for preparing a perovskite solar cell provided by the present invention, the particle size of the abrasive is 10nm-50nm.

[0022] According to a method for preparing a perovskite solar cell provided by the present invention, the grinding head is a wool grinding head, a polyester fiber grinding head, or a nylon fiber grinding head.

[0023] According to a method for fabricating a perovskite solar cell provided by the present invention, if the perovskite solar cell has a conventional structure, the first carrier transport layer is an electron transport layer and the second carrier transport layer is a hole transport layer; if the perovskite solar cell has an inverted structure, the first carrier transport layer is a hole transport layer and the second carrier transport layer is an electron transport layer; the electron transport layer is made of one of tin dioxide, titanium dioxide, zinc oxide, or a fullerene derivative; the hole transport layer is made of one of 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene, triphenylamine polymer, or 3,4-ethylenedioxythiophene:polystyrene sulfonate.

[0024] According to a method for fabricating a perovskite solar cell provided by the present invention, a first carrier transport layer is formed on one side of the transparent conductive electrode by spin coating, vapor deposition, spraying, or blade coating; a second carrier transport layer is formed on the side of the perovskite light-absorbing layer opposite to the first carrier transport layer by spin coating, vapor deposition, spraying, or blade coating.

[0025] According to a second aspect of the present invention, a perovskite solar cell is prepared based on the preparation method of the perovskite solar cell described in any one of the preceding claims, the perovskite solar cell comprising:

[0026] Transparent conductive electrode;

[0027] The first carrier transport layer is disposed on one side of the transparent conductive electrode;

[0028] A perovskite light-absorbing layer is disposed on the side of the first carrier transport layer away from the transparent conductive electrode;

[0029] The second carrier transport layer is disposed on the side of the perovskite light-absorbing layer opposite to the first carrier transport layer; wherein the uniformity of the side of the perovskite light-absorbing layer opposite to the first carrier transport layer is 92%-98%.

[0030] A metal electrode layer is disposed on the side of the second carrier transport layer away from the perovskite light-absorbing layer.

[0031] The above-described one or more technical solutions in the embodiments of the present invention have at least one of the following technical effects:

[0032] According to the method for fabricating perovskite solar cells provided by the present invention, by grinding and polishing the side of the perovskite light-absorbing layer away from the first carrier transport layer, the surface undulation of the perovskite light-absorbing layer can be effectively reduced, resulting in a smooth and uniform surface. Subsequently, a second carrier transport layer is fabricated on the side of the perovskite light-absorbing layer away from the first carrier transport layer. The second carrier transport layer is bonded to the smooth perovskite light-absorbing layer, enhancing the bonding between the second carrier transport layer and the perovskite light-absorbing layer, improving the charge transport extraction efficiency, and overall improving the photoelectric conversion efficiency and stability of the perovskite solar cell.

[0033] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0035] Figure 1 This is a flowchart of the fabrication method of the perovskite solar cell provided in the embodiments of the present invention;

[0036] Figure 2 This is a schematic diagram illustrating the principle of grinding and polishing the side of the perovskite light-absorbing layer away from the first carrier transport layer, as provided in an embodiment of the present invention.

[0037] Figure 3 This is a schematic diagram of the structure of a perovskite solar cell provided in an embodiment of the present invention.

[0038] Figure label:

[0039] 10. Transparent conductive electrode; 20. First carrier transport layer; 30. Perovskite light-absorbing layer; 31. Grinding head; 32. Grinding and polishing slurry; 40. Second carrier transport layer; 50. Metal electrode layer. Detailed Implementation

[0040] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0041] In the description of the embodiments of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0042] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0043] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0044] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0045] The following is combined Figure 1 and Figure 2 This invention describes a method for fabricating a perovskite solar cell according to an embodiment of the present invention.

[0046] Figure 1 A flowchart illustrating the fabrication method of the perovskite solar cell provided in the embodiments of the present invention is shown. Figure 2 This example illustrates the principle of grinding and polishing the side of the perovskite light-absorbing layer away from the first carrier transport layer, as provided in an embodiment of the present invention. Figure 1 and Figure 2 As shown, the fabrication method of perovskite solar cells includes the following steps:

[0047] Step 100: Prepare a first carrier transport layer 20 on one side of the transparent conductive electrode 10.

[0048] The transparent conductive electrode 10 can be made of fluorine-doped tin oxide (FTO) or indium-doped tin oxide (ITO), and the structure of the transparent conductive electrode 10 can be a metal mesh, etc. In this embodiment, the transparent conductive electrode 10 is made of indium-doped tin oxide (ITO).

[0049] Step 200: A perovskite light-absorbing layer 30 is prepared on the side of the first carrier transport layer 20 that is away from the transparent conductive electrode 10.

[0050] Step 300: Grind and polish the side of the perovskite light-absorbing layer 30 that is away from the first carrier transport layer 20.

[0051] Step 400: Prepare a second carrier transport layer 40 on the side of the perovskite light-absorbing layer 30 that is opposite to the first carrier transport layer 20.

[0052] Step 500: A metal electrode layer 50 is prepared on the side of the second carrier transport layer 40 away from the perovskite light-absorbing layer 30 to obtain a perovskite solar cell.

[0053] The metal electrode layer 50 is prepared by distillation. The material of the metal electrode layer 50 can be gold (Au), copper (Cu), or other metal materials.

[0054] According to the method for fabricating a perovskite solar cell provided by the present invention, by grinding and polishing the side of the perovskite light-absorbing layer 30 away from the first carrier transport layer 20, the surface undulation of the perovskite light-absorbing layer 30 can be effectively reduced, resulting in a smooth and uniform surface. Subsequently, a second carrier transport layer 40 is fabricated on the side of the perovskite light-absorbing layer 30 away from the first carrier transport layer 20. The second carrier transport layer 40 is bonded to the smooth perovskite light-absorbing layer 30, which effectively enhances the bonding between the second carrier transport layer 40 and the perovskite light-absorbing layer 30, improves the charge transport extraction efficiency, and enhances the overall photoelectric conversion efficiency and stability of the perovskite solar cell.

[0055] In an embodiment of the present invention, before the step of fabricating the first carrier transport layer 20 on one side of the transparent conductive electrode 10, the method further includes:

[0056] Step 110: Immerse the transparent conductive electrode 10 in detergent for ultrasonic cleaning.

[0057] Step 120: Immerse the transparent conductive electrode 10 in deionized water, acetone and isopropanol in turn for ultrasonic cleaning.

[0058] In an embodiment of the present invention, before the step of sequentially immersing the transparent conductive electrode 10 in deionized water, acetone, and isopropanol for ultrasonic cleaning, the method further includes:

[0059] Step 111: Immerse the transparent conductive electrode 10 in deionized water to remove detergent. Since detergent residue remains on the surface of the transparent conductive electrode 10 after ultrasonic cleaning in the detergent, it is necessary to immerse the transparent conductive electrode 10 in deionized water to remove the detergent.

[0060] In embodiments of the present invention, such as Figure 2 As shown, the step of grinding and polishing the side of the perovskite light-absorbing layer 30 away from the first carrier transport layer 20 includes:

[0061] Step 310: A polishing slurry 32 is dropped onto the side of the perovskite light-absorbing layer 30 that is away from the first carrier transport layer 20.

[0062] The polishing slurry 32 comprises isopropanol (IPA) and N,N-dimethylformamide (DMF). IPA does not react with the perovskite material and is used to disperse the abrasive in the polishing slurry 32. DMF can achieve Oswald ripening, enabling the polishing slurry 32 to recrystallize on the surface of the perovskite light-absorbing layer, further improving the uniformity of the perovskite light-absorbing layer.

[0063] Step 320: The perovskite light-absorbing layer 30 on the side opposite to the first carrier transport layer 20 is ground and polished using a grinding head 31.

[0064] In embodiments of the present invention, the polishing head 31 is a soft polishing head, specifically, a wool polishing head, a polyester fiber polishing head, a nylon fiber polishing head, or other soft polishing heads. In this embodiment, the polishing head 31 is a wool polishing head. By using a soft wool polishing head or other soft polishing head 31 to perform grinding and polishing treatment on the side of the perovskite light-absorbing layer 30 away from the first charge carrier transport layer 20, the perovskite film can be effectively protected, avoiding damage to the perovskite film or even wear through it during the grinding and polishing process caused by the hard and rough polishing head 31.

[0065] By grinding and polishing the side of the perovskite light-absorbing layer 30 away from the first carrier transport layer 20, the surface unevenness of the perovskite light-absorbing layer 30 is reduced, making the surface of the perovskite light-absorbing layer 30 smooth and uniform. Compared with the perovskite light-absorbing layer 30 without grinding and polishing treatment, the perovskite light-absorbing layer 30 obtained after grinding and polishing treatment has a smoother, flatter, and more uniform surface, which effectively improves the hydrophobicity of the perovskite light-absorbing layer 30 surface. At the same time, the second carrier transport layer 40 adheres to the flat perovskite light-absorbing layer 30, enhancing the adhesion between the second carrier transport layer 40 and the perovskite light-absorbing layer 30, improving the carrier extraction and transport capability and the wet stability of the perovskite solar cell.

[0066] It should be noted that the grinding and polishing process involves physical friction and chemical recrystallization to grind and polish the perovskite light-absorbing layer 30. This method ensures that the perovskite lattice is not damaged by physical friction during the grinding and polishing process, thus avoiding increased moisture erosion and a decrease in battery efficiency and stability. The grinding head 31 wraps around the perovskite light-absorbing layer 30 from top to bottom, polishing the entire perovskite light-absorbing layer 30 to ensure the flatness and uniformity of the entire perovskite film.

[0067] In an embodiment of the present invention, the polishing slurry 32 is composed of abrasive and dispersion, which are stirred evenly in a specific ratio. The abrasive is one or a combination of diamond, alumina, silicon dioxide, or silicon carbide. The abrasive material does not react with the perovskite material. By using the abrasive made from the above materials to contact the perovskite light-absorbing layer 30, the abrasive does not affect the growth of the perovskite crystal, thus avoiding a shortening of the absorption spectrum of the perovskite light-absorbing layer 30 and preventing a reduction in the photoelectric conversion efficiency of the perovskite solar cell. The dispersion is a mixture of 95% by volume of the antisolvent isopropanol (IPA) and 5% by volume of N,N-dimethylformamide (DMF). The abrasive used does not react with the perovskite material. By using the dispersion made from the above materials to contact the perovskite light-absorbing layer 30, the perovskite light-absorbing layer 30 does not dissolve in large quantities in the dispersion, but only recrystallizes on the surface, thus avoiding a short circuit in the perovskite solar cell.

[0068] It should be noted that the dispersion is prepared by mixing 95% by volume of the antisolvent isopropanol (IPA) and 5% by volume of N,N-dimethylformamide (DMF). IPA is responsible for dispersing the abrasive, while DMF acts as an Oswald curing agent. The 5% by volume of DMF can effectively help recrystallize the surface of the perovskite light-absorbing layer, further improving the uniformity of the perovskite light-absorbing layer surface after grinding and polishing, as well as the stability of the battery. At the same time, it reduces the erosion of moisture and improves the battery life.

[0069] In embodiments of the present invention, the abrasive particle size is 10nm-50nm, specifically, the abrasive particle size can be 10nm, 20nm, 30nm or other sizes. By using abrasives with nanoscale particle size, nanoscale precision grinding and polishing can be achieved. During the grinding and polishing process, it can effectively avoid the active layer of the perovskite light-absorbing layer 30 being worn through due to excessively large abrasive particle size, further reducing the short-circuit risk of perovskite solar cells.

[0070] It should be noted that the smaller the abrasive particle size, the less thickness of the perovskite light-absorbing layer will be reduced during the grinding and polishing process. The abrasive particle size needs to be determined based on the actual thickness to be removed during grinding.

[0071] It should also be noted that the thickness of the perovskite light-absorbing layer 30 can be any thickness required, and the surface roughness of the perovskite light-absorbing layer 30 does not need to be considered. During the grinding and polishing process, the thickness of the perovskite light-absorbing layer 30 is affected by the abrasive particle size, the rotation speed of the grinding head 31, and the pressure of the grinding head 31.

[0072] In embodiments of the present invention, the perovskite solar cell can be either a formal structure or an inverted structure. If the perovskite solar cell is a formal structure, the first carrier transport layer 20 is an electron transport layer, and the second carrier transport layer 40 is a hole transport layer; if the perovskite solar cell is an inverted structure, the first carrier transport layer 20 is a hole transport layer, and the second carrier transport layer 40 is an electron transport layer. The electron transport layer is made of one of tin dioxide (SnO2), titanium dioxide (TiO2), zinc oxide (ZnO), C60, or fullerene derivatives (PCBM). The hole transport layer is made of one of 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (Spiro-OMeTAD), triphenylamine polymer (PTAA), or 3,4-ethylenedioxythiophene:polystyrene sulfonate (PEDOT:PSS).

[0073] In an embodiment of the present invention, the first carrier transport layer 20 is formed on one side of the transparent conductive electrode 10 by spin coating, vapor deposition, spraying or blade coating; the second carrier transport layer 40 is formed on the side of the perovskite light-absorbing layer 30 away from the first carrier transport layer 20 by spin coating, vapor deposition, spraying or blade coating.

[0074] In an embodiment of the present invention, Figure 3 A schematic diagram of the structure of a perovskite solar cell provided in an embodiment of the present invention is illustrated. The perovskite solar cell provided by the present invention is prepared based on the preparation method of the perovskite solar cell described in any of the above embodiments, such as... Figure 3As shown, the perovskite solar cell includes a transparent conductive electrode 10, a first carrier transport layer 20, a perovskite light-absorbing layer 30, a second carrier transport layer 40, and a metal electrode layer 50. The first carrier transport layer 20 is disposed on one side of the transparent conductive electrode 10. The transparent conductive electrode 10 can be made of fluorine-doped tin oxide (FTO) or indium-doped tin oxide (ITO), and its structure can be a metal mesh, etc. In this embodiment, the transparent conductive electrode 10 is made of indium-doped tin oxide (ITO).

[0075] The perovskite light-absorbing layer 30 is disposed on the side of the first carrier transport layer 20 away from the transparent conductive electrode 10, and the material of the perovskite light-absorbing layer 30 is an organic-inorganic perovskite material. The second carrier transport layer 40 is disposed on the side of the perovskite light-absorbing layer 30 away from the first carrier transport layer 20. After the perovskite light-absorbing layer 30 is prepared, a polishing slurry 32 is dropped onto the side of the perovskite light-absorbing layer 30 away from the first carrier transport layer 20. A soft polishing head 31 with different rotation speeds is used to wrap the perovskite light-absorbing layer 30 from top to bottom. Under the combined action of the soft polishing head 31 and the polishing slurry 32, the perovskite light-absorbing layer 30 is polished as a whole, so that the uniformity of the perovskite light-absorbing layer 30 away from the first carrier transport layer 20 is 92%-98%. Specifically, after the whole-body polishing, the uniformity of the perovskite light-absorbing layer 30 away from the first carrier transport layer 20 is 97%.

[0076] The metal electrode layer 50 is disposed on the side of the second carrier transport layer 40 opposite to the perovskite light-absorbing layer 30, and the metal electrode layer 50 is prepared by distillation. The material of the metal electrode layer 50 can be gold (Au), copper (Cu), or other metal materials.

[0077] The following provides specific examples of the fabrication methods for formal perovskite solar cells and inverted perovskite solar cells.

[0078] In an embodiment of the present invention, the method for fabricating a formal perovskite solar cell includes the following steps:

[0079] Step 1010: Immerse the glass substrate with indium tin oxide (ITO) in a detergent for ultrasonic cleaning, then rinse off the detergent with deionized water, and then immerse it in deionized water, acetone and isopropanol for ultrasonic cleaning in sequence.

[0080] Step 1011: Spin-coat a SnO2 aqueous dispersion diluted with water at a volume ratio of 1:2 onto one side of the ITO substrate. The spin-coating speed is 4000 rpm and the spin-coating time is 30 seconds. After spin-coating, keep the substrate at 150°C for 30 minutes.

[0081] Step 1012: Transfer the ITO substrate and place it in a UV-ozone cleaner for 20 minutes. Then transfer it to a glove box and allow it to cool naturally to room temperature to complete the annealing process, thus completing the preparation of the first carrier transport layer 20. At this point, the first carrier transport layer 20 is an electron transport layer.

[0082] Step 1013: Methylamine iodine (MAI), formamidinium iodine (FAI), and lead iodide (PbI2) are dissolved in a mixed solvent of dimethyl sulfoxide (DMSO) and N,N-dimethylformamide (DMF) to obtain a first mixed solution, wherein the volume ratio of DMSO to DMF is 1:9. The solution is heated to 70°C and completely dissolved. The first mixed solution is then spin-coated onto the side of the electron transport layer prepared in the previous step that is away from the ITO substrate. The spin-coating speed is 5000 rpm and the spin-coating time is 30 seconds. After spin-coating, the layer is kept at 100°C for 30 minutes and then naturally cooled to room temperature to complete the annealing, thus completing the preparation of the perovskite light-absorbing layer 30.

[0083] Step 1014: A polishing slurry 32 is dropped onto the side of the perovskite light-absorbing layer 30 that is away from the electron transport layer. A wool polishing head 31 with a rotation speed of 1000 rpm is used to polish the side of the perovskite light-absorbing layer 30 that is away from the electron transport layer. The perovskite light-absorbing layer 30 is polished to about 500 nm, thus completing the polishing treatment of the side of the perovskite light-absorbing layer 30 that is away from the electron transport layer.

[0084] Step 1015: 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (Spiro-OMeTAD) was dissolved in chlorobenzene (CB) solvent to obtain a second mixed solution with a concentration of 72.3 mg / mL. The solution was stirred at high speed until completely dissolved. Then, 28.8 μL of 4-tert-butylpyridine and 17.5 μL of an acetonitrile solution of lithium bis(trifluoromethanesulfonyl)imide (Li-TFSI) (concentration 520 mg / mL) were added sequentially to 1 mL of the second mixed solution, and the mixture was stirred until homogeneous. The obtained solution is then spin-coated onto the surface of the perovskite light-absorbing layer 30 after grinding and polishing, that is, the side of the perovskite light-absorbing layer 30 away from the electron transport layer. The spin-coating speed is 4000 revolutions per minute and the spin-coating time is 30 seconds. After the spin-coating is completed, the preparation of the second carrier transport layer 40 is completed. At this time, the second carrier transport layer 40 is the hole transport layer.

[0085] Step 1016: Transfer the semi-finished battery with hole transport layer prepared in the previous step to the thermal evaporation chamber, and deposit a layer of gold (Au) on the side of the hole transport layer away from the perovskite light-absorbing layer 30, thus completing the preparation of the formal perovskite solar cell in this embodiment.

[0086] In an embodiment of the present invention, the method for fabricating an inverted perovskite solar cell includes the following steps:

[0087] Step 1020: Immerse the glass substrate with indium tin oxide (ITO) in a detergent for ultrasonic cleaning, then rinse off the detergent with deionized water, and then immerse it in deionized water, acetone and isopropanol for ultrasonic cleaning in sequence.

[0088] Step 1021: Dissolve triphenylamine polymer (PTAA) in chlorobenzene (CB) to obtain a third mixed solution. The concentration of PTAA in the third mixed solution is 2 mg / mL. Spin-coat the solution onto one side of the ITO substrate in a glove box at a spin speed of 4000 rpm for 30 seconds. After spin-coating, heat the solution at 150°C for 20 minutes and allow it to cool naturally to room temperature for annealing. This completes the preparation of the first carrier transport layer 20, which is now a hole transport layer.

[0089] Step 1022: Weigh out five powders—lead iodide (PbI2), lead bromide (PbBr2), formamidinium iodide (FAI), methylamine bromide (MABr), and cesium iodide (CsI)—into the same reagent bottle according to the required proportions. Add a mixed solvent of DMSO and DMF in a volume ratio of 1:4. Then, heat the solution on a 90°C hot plate until fully dissolved to obtain a fourth mixed solution. Finally, cool the solution to room temperature for later use.

[0090] Step 1023: The fourth mixed solution is spin-coated onto the side of the hole transport layer away from the ITO substrate using a two-step method. The first spin-coating speed is 2000 rpm and the spin-coating time is 10 seconds. The second spin-coating speed is 6000 rpm and the spin-coating time is 30 seconds. 15 seconds before the end of the second spin-coating step, 100 μL of antisolvent is added dropwise to the side of the hole transport layer away from the ITO substrate. After spin-coating, the layer is heated at 100°C and held for 60 minutes, followed by natural cooling and annealing to complete the preparation of the perovskite light-absorbing layer 30.

[0091] Step 1024: A polishing slurry 32 is dropped onto the side of the perovskite light-absorbing layer 30 that is away from the electron transport layer. A wool polishing head 31 with a rotation speed of 1000 rpm is used to polish the side of the perovskite light-absorbing layer 30 that is away from the electron transport layer. The perovskite light-absorbing layer 30 is polished to about 500 nm, thus completing the polishing treatment of the side of the perovskite light-absorbing layer 30 that is away from the electron transport layer.

[0092] Step 1025, the fullerene derivative (PC) 61 BM) is dissolved in chlorobenzene (CB) solvent to obtain a fifth mixed solution, in which PC is... 61The BM concentration is 20 mg / mL, and the mixture is stirred on a hot plate at 60°C for 2 hours. Then, it is spin-coated onto the side of the perovskite light-absorbing layer 30 prepared in the previous step that is away from the hole transport layer. The spin-coating speed is 1000 rpm and the spin-coating time is 30 seconds, which completes the preparation of the second carrier transport layer 40. At this time, the second carrier transport layer 40 is an electron transport layer.

[0093] Step 1026: A saturated isopropanol solution of copper bath (BCP) is spin-coated onto the side of the electron transport layer away from the perovskite light-absorbing layer 30 to form a buffer layer. The spin-coating speed is 1000 rpm and the spin-coating time is 30 seconds. Then, the spin-coated battery semi-finished product is transferred to a metal evaporation chamber. Using a vacuum thermal evaporation method in conjunction with a mask, an 80 nm thick copper (Cu) electrode is prepared on the side of the electron transport layer away from the perovskite light-absorbing layer 30. This completes the fabrication of the inverted perovskite solar cell in this embodiment.

[0094] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a perovskite solar cell, characterized in that, Includes the following steps: A first carrier transport layer is fabricated on one side of a transparent conductive electrode; A perovskite light-absorbing layer is prepared on the side of the first carrier transport layer away from the transparent conductive electrode; The side of the perovskite light-absorbing layer that is away from the first carrier transport layer is ground and polished. A second charge carrier transport layer is prepared on the side of the perovskite light-absorbing layer opposite to the first charge carrier transport layer; A metal electrode layer is fabricated on the side of the second carrier transport layer away from the perovskite light-absorbing layer to obtain the perovskite solar cell.

2. The method for preparing a perovskite solar cell according to claim 1, characterized in that, Before the step of fabricating the first carrier transport layer on one side of the transparent conductive electrode, the method further includes: The transparent conductive electrode is immersed in detergent for ultrasonic cleaning. The transparent conductive electrode was sequentially immersed in deionized water, acetone, and isopropanol for ultrasonic cleaning.

3. The method for preparing a perovskite solar cell according to claim 2, characterized in that, Before the step of sequentially immersing the transparent conductive electrode in deionized water, acetone, and isopropanol for ultrasonic cleaning, the method further includes: The transparent conductive electrode is immersed in deionized water to remove detergent.

4. The method for preparing a perovskite solar cell according to any one of claims 1 to 3, characterized in that, The step of grinding and polishing the side of the perovskite light-absorbing layer away from the first carrier transport layer includes: A polishing slurry is dropped onto the side of the perovskite light-absorbing layer that is away from the first carrier transport layer. The perovskite light-absorbing layer on the side opposite to the first carrier transport layer is ground and polished using a grinding head.

5. The method for preparing a perovskite solar cell according to claim 4, characterized in that, The grinding and polishing slurry consists of abrasive and dispersion. The abrasive is one or a combination of diamond, alumina, silicon dioxide, or silicon carbide. The dispersion is a mixture of 95% isopropanol (by volume) and 5% N,N-dimethylformamide (by volume).

6. The method for preparing a perovskite solar cell according to claim 5, characterized in that, The abrasive has a particle size of 10nm-50nm.

7. The method for preparing a perovskite solar cell according to claim 4, characterized in that, The grinding head is a wool grinding head, a polyester fiber grinding head, or a nylon fiber grinding head.

8. The method for preparing a perovskite solar cell according to any one of claims 1 to 3, characterized in that, If the perovskite solar cell has a conventional structure, then the first carrier transport layer is an electron transport layer and the second carrier transport layer is a hole transport layer; if the perovskite solar cell has an inverted structure, then the first carrier transport layer is a hole transport layer and the second carrier transport layer is an electron transport layer; the electron transport layer is made of one of tin dioxide, titanium dioxide, zinc oxide, or a fullerene derivative; the hole transport layer is made of one of 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene, triphenylamine polymer, or 3,4-ethylenedioxythiophene:polystyrene sulfonate.

9. The method for preparing a perovskite solar cell according to any one of claims 1 to 3, characterized in that, The first carrier transport layer is formed on one side of the transparent conductive electrode by spin coating, vapor deposition, spraying or blade coating; the second carrier transport layer is formed on the side of the perovskite light-absorbing layer opposite to the first carrier transport layer by spin coating, vapor deposition, spraying or blade coating.

10. A perovskite solar cell, characterized in that, The perovskite solar cell is prepared according to the method for preparing a perovskite solar cell according to any one of claims 1 to 9, and the perovskite solar cell comprises: Transparent conductive electrode; The first carrier transport layer is disposed on one side of the transparent conductive electrode; A perovskite light-absorbing layer is disposed on the side of the first carrier transport layer away from the transparent conductive electrode; The second carrier transport layer is disposed on the side of the perovskite light-absorbing layer opposite to the first carrier transport layer; wherein the uniformity of the side of the perovskite light-absorbing layer opposite to the first carrier transport layer is 92%-98%. A metal electrode layer is disposed on the side of the second carrier transport layer away from the perovskite light-absorbing layer.

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