A <110>-oriented low-dimensional perovskite thin film and a preparation method thereof for a solar cell

Abstract

The present invention relates to a <110>-oriented low-dimensional perovskite thin film and a method for preparing a solar cell thereof, belonging to the field of optoelectronic materials and devices. In this invention, a specific organic diamine salt (2,2-hexanedioxy-bis-hexylamine iodide, EDBEI2), chloromethylamine, and lead iodide are dissolved in a methylammonium acetate solution according to different stoichiometric ratios to prepare a perovskite precursor solution. Then, the solution is spin-coated onto an ITO substrate deposited with PEDOT:PSS by a heating spin-coating method, and annealed to form a dense, uniform, and highly stable low-dimensional perovskite thin film. The whole process is completely operated in air. Then, a PCBM electron transport layer is spin-coated on the thin film, and a modified layer LiF and a metal Al electrode are deposited by vacuum evaporation technology to complete the preparation of the device.

Description

Technical Field

[0001] The present invention relates to a <110>-oriented low-dimensional perovskite thin film and a preparation method thereof for a solar cell, in particular to a <110>-oriented low-dimensional perovskite thin film with high quality and a highly efficient and stable <110>-oriented low-dimensional perovskite solar cell that can be realized by using 2,2-hexanedioxy-bis-hexylamine iodide, belonging to the field of optoelectronic materials and technologies. Background Art

[0002] Facing the problem of energy shortage in current social development, solar energy has become one of the most promising renewable energies due to its characteristics of safety, pollution-free, and wide application range. Solar cells that convert solar energy into electrical energy by the photovoltaic effect have become one of the important strategies to fill the energy demand. Perovskite solar cells were first reported in 2009, and then they have developed rapidly. The current certified photoelectric conversion efficiency has reached 25.5%. The high photoelectric conversion efficiency of perovskite solar cells, combined with their characteristics of low cost and simple preparation process, makes them strong competitors for the next-generation commercial new photovoltaic devices. However, due to their instability to water, oxygen, light, high temperature, etc., their practical applications are greatly limited.

[0003] To overcome this instability, researchers have made a lot of efforts. Incorporating large organic amine cations into traditional three-dimensional perovskites to reduce their dimension to two-dimensional or quasi-two-dimensional has become a popular and effective way. The reasons for the improved stability of two-dimensional or low-dimensional perovskites mainly include the following two points: one is that large organic amine cations contain hydrophobic alkyl chains, which can effectively isolate water vapor in the air; the other is that the introduction of organic amine cations can effectively inhibit ion migration and self-doping effects inside the perovskite, improving the stability of the perovskite structure.

[0004] Cutting three-dimensional perovskites along different directions by organic amine cations can obtain low-dimensional perovskites with different orientations. When the organic amine cations are cut along the <100> direction, <100>-oriented low-dimensional perovskites with inorganic octahedra arranged in a "one" shape can be obtained, and this structure is the most widely used in low-dimensional perovskites. Similarly, when cutting along the <110> and <111> directions, <110>- and <111>-oriented low-dimensional perovskites can be obtained respectively. Among them, the inorganic octahedra of <110>-oriented are arranged in a "Z" shape, and this structure has only been reported in the field of perovskite luminescence applications. The inorganic octahedra of <111>-oriented are further distorted to form a zero-dimensional or one-dimensional structure, and there are few reports on low-dimensional perovskites with this structure. It should be noted that the most commonly used low-dimensional perovskite solar cells are <100>-oriented, and the application potential of <110>-oriented low-dimensional perovskites in solar cells has not been explored yet. Summary of the Invention

[0005] The technical problem to be solved by the present invention is: in view of the current research on low-dimensional perovskite solar cells which mostly focuses on the <100> orientation, a novel preparation method and application of a low-dimensional perovskite thin film and a solar cell based on the <110> orientation are proposed.

[0006] To solve the above technical problem, the technical solution proposed by the present invention is: a preparation method of a low-dimensional perovskite thin film and a solar cell based on the <110> orientation, comprising the following steps:

[0007] (1) Mix acetic acid and methylamine in a molar ratio of 1:1.5 and stir to prepare methylammonium acetate.

[0008] (2) Dissolve lead iodide, chloromethylamine, and 2,2-dihexylenedioxy-bis-hexylammonium iodide in the methylammonium acetate solution according to different stoichiometric ratios to prepare a perovskite precursor solution, and then stir at 60 °C for 2 hours.

[0009] (3) Spin-coat the hole transport material on the ITO conductive glass.

[0010] (4) Spin-coat the prepared perovskite precursor solution on the ITO conductive substrate with a hole transport layer, and anneal at 100 °C for 5 min to obtain a dense and uniform active layer.

[0011] (5) Spin-coat the electron transport layer on the perovskite layer.

[0012] (6) Vacuum deposit a modification layer and a metal electrode on the electron transport layer. The structural formula of 2,2-dihexylenedioxy-bis-hexylammonium iodide in step (2) is NH3(CH2)2O(CH2)2O(CH2)2NH3I 2， The stoichiometric ratio in step (2) refers to the structural general formula (NH3(CH2)2O(CH2)2O(CH2)2NH3)(CH3NH3) n-1 Pb n X 3n+1 , where X refers to the halogens chlorine (Cl) and iodine (I), and n = 5.

[0013] Preferably, in step (1), acetic acid and methylamine are stirred in an ice-water bath for 2 hours.

[0014] Preferably, the concentration of the perovskite precursor in step (2) is 230 mg / ml.

[0015] Preferably, the hole transport layer spin-coated on the transparent conductive ITO glass in step (3) is PEDOT:PSS, and the specific steps are as follows:

[0016] (1) The spin-coating condition is to spin at 5000 revolutions for 50 seconds.

[0017] (2) After spin coating, anneal at 120 °C for 30 minutes.

[0018] Preferably, in step (4), spin coating is carried out on a substrate at 90 °C by the heating spin coating method.

[0019] Preferably, the electron transport layer spin-coated on the perovskite layer is PCBM, and the specific steps are as follows:

[0020] (1) Dissolve 18 mg of PCBM in 1 ml of chlorobenzene, stir overnight at 60 °C, and let it stand for later use.

[0021] (2) The spin coating conditions are spin coating at 1000 rpm for 60 seconds and 2000 rpm for 2 seconds.

[0022] Preferably, the modification layer in step (6) is LiF, and the metal electrode is Al. The specific steps are as follows:

[0023] (1) The thickness of the LiF modification layer is 1 nm;

[0024] (2) The thickness of the metal Al electrode is 100 nm.

[0025] To solve the above technical problems, another technical solution proposed by the present invention is: the novel perovskite thin film and solar cell prepared by the new method of the <110>-oriented low-dimensional perovskite thin film and its solar cell.

[0026] To solve the above technical problems, another technical solution proposed by the present invention is: the application of the new method of the <110>-oriented low-dimensional perovskite thin film and its solar cell in the optoelectronic field.

[0027] Advantages of the present invention:

[0028] (1) Different from most reports, using 2,2'-hexanedioxy-bis-hexylamine iodide as the self-assembled molecule of the low-dimensional perovskite thin film and solar cell, a highly efficient and highly stable <110>-oriented low-dimensional perovskite solar cell is realized, and the great potential of the <110> orientation in the field of low-dimensional perovskites is explored.

[0029] (2) A dense and uniform high-quality thin film is obtained.

[0030] (3) The preparation process has simple steps, low-temperature operation, and is completed in air.

[0031] (4) It is found through research that in the <110>-oriented low-dimensional perovskite, the lead iodide octahedra are arranged in a "Z" shape, and the amino groups are "wrapped" in the octahedron stacking voids, which is beneficial to enhancing the interaction between the organic amine and the inorganic octahedron and improving the stability of the structure.

[0032] (5) It is found that the <110>-oriented low-dimensional perovskite can effectively shorten the distance of the organic insulating layer, slowing down the hindering effect of organic amines on charge transport. Therefore, based on the <110>-oriented low-dimensional perovskite, the device efficiency of 13.87% is obtained while improving the stability. In contrast, the device efficiency of only 8.85% is obtained for the <100>-oriented low-dimensional perovskite, providing a new idea for high-efficiency and high-stability low-dimensional perovskites.

[0033] (6) It is found that the <110>-oriented low-dimensional perovskite shows better stability than the <100>-oriented low-dimensional perovskite, and its film can be placed in air for one month without aging.

[0034] (7) The present invention first uses 2,2-hexanedioxy-bishexylamine iodide to prepare a <110>-oriented low-dimensional perovskite film and its solar cell. It is found that the main difference between this <110>-oriented low-dimensional perovskite based on 2,2-hexanedioxy-bishexylamine iodide and the traditional <100> structure is that the lead iodide octahedra in the <110>-oriented low-dimensional perovskite are arranged in a "Z" shape, and this structure has two main advantages: one is to enhance the interaction force between the amino group (-NH3 + ) of the organic amine molecule and the inorganic octahedron. The amino group (-NH3 + ) at the end of the organic amine molecule in the low-dimensional perovskite is connected to the upper and lower octahedra by hydrogen bonding interaction. In the low-dimensional perovskite of the present invention, the -NH3 + of one end of the organic amine molecule and the region forming hydrogen bonds with the halogen are "wrapped" in a unique octahedron structure, and the -NH3 + of the other end interacts with the O in the adjacent 2,2-hexanedioxy-bishexylamine molecule to form a hydrogen bond. These two interactions make the structure of the low-dimensional perovskite more stable; the other is to shorten the distance of the organic insulating layer, which is beneficial to charge transport. The distance between the two rows of octahedra closest to the organic amine molecule in the inorganic octahedron stacking layer in the low-dimensional perovskite is the distance of the organic insulating layer. In the <110>-oriented low-dimensional perovskite structure, this insulating distance is shorter than the inherent chain length of the organic amine molecule, indicating that this structure can effectively reduce the hindrance of the organic amine molecule to charge transport. Therefore, the present invention prepares a high-quality <110>-oriented low-dimensional perovskite film and a highly efficient and stable <110>-oriented low-dimensional perovskite solar cell, and discovers the great potential of the <110>-oriented low-dimensional perovskite in photovoltaic devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The present invention will be further described below with reference to the drawings.

[0036] Figure 1Schematic diagram of the <110>-oriented two-dimensional perovskite (n = 1) of the present invention and the <100>-oriented two-dimensional perovskite (n = 1) of the comparative example.

[0037] Figure 2 XRD diffraction pattern of the films of the <110>-oriented two-dimensional perovskite (n = 1) of the present invention and the <100>-oriented two-dimensional perovskite (n = 1) of the comparative example.

[0038] Figure 3 UV-visible light absorption and photoluminescence spectra of the films of the <110>-oriented two-dimensional perovskite (n = 1) of the present invention and the <100>-oriented two-dimensional perovskite (n = 1) of the comparative example.

[0039] Figure 4 Scanning electron microscope image of the films of the <110>-oriented low-dimensional perovskite (n = 5) of the present invention and the <100>-oriented low-dimensional perovskite (n = 5) of the comparative example.

[0040] Figure 5 J-V curve of the energy conversion efficiency of the solar cells of the <110>-oriented low-dimensional perovskite (n = 5) of the present invention and the <100>-oriented low-dimensional perovskite (n = 5) of the comparative example.

[0041] Figure 6 Stability test of the films of the <110>-oriented low-dimensional perovskite (n = 5) of the present invention and the <100>-oriented low-dimensional perovskite (n = 5) of the comparative example.

[0042] Figure 7 Schematic diagram of the structure of the solar cell device of the present invention. Detailed implementation mode

[0043] Example 1

[0044] This example is the <110>-oriented low-dimensional perovskite film and its solar cell of the present invention for better understanding of the present invention. It mainly includes the following steps:

[0045] Step 1) Take 90 ml of methylamine and place it in a round-bottom flask in an ice-water bath. Slowly add 27.6 ml of glacial acetic acid to it. After 2 h in the ice-water bath, rotary evaporate at 55 °C until no liquid drops. Prepare methylamine acetate for later use.

[0046] Step 2) Take a certain amount of the organic amine 2,2-hexanediyl dioxy-bis-hexylamine and place it in a round-bottom flask in an ice-water bath. Add HI to it in a molar ratio of 1:2.1. After 2 h in the ice-water bath, rotary evaporate at 55 °C until no liquid drops. Wash the rotary-evaporated solid with ether and dry it in vacuum at 60 °C to obtain the solid NH3(CH2)2O(CH2)2O(CH2)2NH3I2 (EDBEI2).

[0047] Step 3) Clean the ITO conductive glass in the order of ethanol, cleaning agent, ultrapure water, and acetone. Ultrasonic in ethanol for 15 minutes each, dry with nitrogen, and then dry in an oven at 100 °C for 30 minutes.

[0048] Step 4) Weigh 18 mg of PCBM and completely dissolve it in 1 ml of chlorobenzene solvent, and stir overnight at 60 °C.

[0049] Step 5) According to the structural formula (EDBE)(CH3NH3)4Pb5X 16 Weigh 177.96 mg of lead iodide, 20.85 mg of chloromethylamine, and 31.19 mg of EDBEI2 prepared in Step 2), and dissolve them in 1 ml of methylammonium acetate solvent prepared in Step 1). Stir at 60 °C for 2 hours until completely dissolved to prepare a perovskite precursor solution with a concentration of 230 mg / ml.

[0050] Step 6) Treat the cleaned ITO substrate in Step 3) with ultraviolet ozone for 15 minutes.

[0051] Step 7) Take 45 μL of the hole transport material PEDOT:PSS and drop it onto the ITO substrate treated in Step 6). Use a spin coater to spin coat a film at a speed of 5000 revolutions per minute for 50 seconds, and then anneal the spin-coated PEDOT:PSS on the ITO at 120 °C for 30 minutes.

[0052] Step 8) Place the spin-coated ITO conductive substrate with the hole transport layer completed in Step 7) on a heating spin coater and preheat for 5 minutes.

[0053] Step 9) Take 100 μL of the perovskite precursor solution prepared in Step 5) and drop it onto the ITO substrate preheated in Step 8). Spin coat a film and then anneal to form a perovskite thin film. The spin coating speed of the perovskite precursor solution is 4000 revolutions per minute for 20 seconds, and anneal at 100 °C in air for 5 minutes.

[0054] Step 10) Spin coat the electron transport material prepared in Step 4) onto the perovskite thin film in Step 9). Spin coat PCBM at 1000 revolutions per minute for 60 seconds, and then at 2000 revolutions per minute for 2 seconds to form an electron transport layer.

[0055] Step 11) Use vacuum evaporation technology to evaporate 1 nm of LiF on the electron transport layer in Step 10), and then evaporate 100 nm of metal electrode Al. Thus, a perovskite solar cell is fabricated.

[0056] Step 12) Under standard test conditions (AM1.5G illumination), the device performance parameters of the low-dimensional perovskite solar cell prepared in this example are as follows: the energy conversion efficiency is 13.87%, the open-circuit voltage is 1.01 V, and the short-circuit current is 18.59 mA / cm 2 , and the fill factor is 73.61%.

[0057] Comparative Example 1

[0058] This comparative example is a low-dimensional perovskite thin film and its solar cell based on <100> orientation. The barrier layer used for the <100>-oriented low-dimensional perovskite is an organic amine 1,8-octanediamine (ODA) similar in chain length and structure to the above EDBE for better understanding of the present invention. It mainly includes the following steps:

[0059] Step 1) Take 90 ml of methylamine and place it in a round-bottom flask in an ice-water bath. Slowly add 27.6 ml of glacial acetic acid dropwise to it. After 2 hours in the ice-water bath, rotary evaporate at 55 °C until no liquid drips, and prepare methylamine acetate for later use.

[0060] Step 2) Take a certain amount of the organic amine 1,8-octanediamine and place it in a round-bottom flask in an ice-water bath. Add HI to it in a molar ratio of 1:2.1. After 2 hours in the ice-water bath, rotary evaporate at 55 °C until no liquid drips. Wash the rotary-evaporated solid with ether and dry it in a vacuum at 60 °C to obtain NH3(CH2)8NH3I2 (ODAI2) solid.

[0061] Step 3) Clean the ITO conductive glass in the following order: ethanol, cleaning agent, ultrapure water, acetone. Ultrasonic in ethanol for 15 minutes each, blow dry with nitrogen, and dry in an oven at 100 °C for 30 minutes.

[0062] Step 4) Weigh 18 mg of PCBM and completely dissolve it in 1 ml of chlorobenzene solvent. Stir overnight at 60 °C.

[0063] Step 5) According to the structural formula (ODA)(CH3NH3)4Pb5X 16 Weigh 178.20 mg of lead iodide, 20.88 mg of chloromethylamine, and 30.92 mg of ODAI2 prepared in Step 2), and dissolve them in 1 ml of the methylamine acetate solvent prepared in Step 1). Stir at 60 °C for 2 hours until completely dissolved to prepare a perovskite precursor solution with a concentration of 230 mg / ml.

[0064] Step 6) Treat the ITO substrate cleaned in Step 3) with ultraviolet ozone for 15 minutes.

[0065] Step 7) Take 45 μL of the hole transport material PEDOT:PSS and drop it onto the ITO substrate processed in step 6). Use a spin coater to spin coat into a film at a rotation speed of 5000 revolutions per minute for 50 seconds, and then anneal the ITO coated with PEDOT:PSS at 120 °C for 30 minutes.

[0066] Step 8) Place the ITO conductive substrate with the spin-coated hole transport layer completed in step 7) on a heating spin coater and preheat for 5 min.

[0067] Step 9) Take 100 μL of the perovskite precursor solution prepared in step 5) and drop it onto the ITO substrate preheated in step 8). Spin coat into a film and then anneal to form a perovskite thin film. The rotation speed for spin coating the perovskite precursor solution is 4000 revolutions per minute for 20 seconds, and anneal at 100 °C in air for 5 min.

[0068] Step 10) Spin coat the electron transport material prepared in step 4) onto the perovskite thin film in step 9). Spin coat PCBM at 1000 revolutions per minute for 60 seconds, and then at 2000 revolutions per minute for 2 seconds to form an electron transport layer.

[0069] Step 11) Using vacuum evaporation technology, evaporate 1 nm of LiF on the electron transport layer in step 10), and then evaporate 100 nm of the metal electrode Al. Thus, the perovskite solar cell is fabricated. Step 12) Under standard test conditions (AM1.5 G illumination), the device performance parameters of the low-dimensional perovskite solar cell based on the <100> orientation prepared in this example are as follows: the photoelectric conversion efficiency is 8.85%, the open-circuit voltage is 1.01 V, the short-circuit current is 11.26 mA / cm 2 , and the fill factor is 78.16%; Figure 1 Shows the structural differences between the <110> and <100> orientations, Figure 2 and Figure 3 The characterization results verify the existence of the <110> and <100> orientations. Compared with the <110> orientation, the structural arrangement of the inorganic octahedra in the <100> orientation is more regular. Therefore, the XRD diffraction peak angles of the low-dimensional perovskite with the <100> orientation appear in multiples, while the XRD diffraction peak angles of the low-dimensional perovskite with the <110> orientation have no obvious pattern; similarly, the absorption and photoluminescence spectra of the low-dimensional perovskite with the <110> orientation show a wider peak range compared with the <100> orientation.

[0070] Comparative Example 2

[0071] This example is about the low-dimensional perovskite thin films and their solar cells based on the <110> orientation with different n values of the present invention for better understanding of the present invention. It mainly includes the following steps:

[0072] Step 1) Take 90 ml of methylamine and place it in a round-bottom flask in an ice bath. Slowly add 27.6 ml of glacial acetic acid dropwise to it. After 2 hours in the ice bath, rotary evaporate at 55 °C until no more liquid drips, and prepare methylamine acetate for later use.

[0073] Step 2) Take a certain amount of the organic amine 2,2-hexamethylene dioxy-bis-hexylamine and place it in a round-bottom flask in an ice bath. Add HI to it in a molar ratio of 1:2.1. After 2 hours in the ice bath, rotary evaporate at 55 °C until no more liquid drips. Wash the rotary-evaporated solid with ether and dry it in a vacuum at 60 °C to obtain the solid NH3(CH2)2O(CH2)2O(CH2)2NH3I2 (EDBEI2).

[0074] Step 3) Clean the ITO conductive glass in the order of ethanol, cleaning agent, ultrapure water, and acetone. Ultrasonic each in ethanol for 15 minutes, dry with nitrogen, and then dry in an oven at 100 °C for 30 minutes.

[0075] Step 4) Weigh 18 mg of PCBM and completely dissolve it in 1 ml of chlorobenzene solvent, and stir overnight at 60 °C.

[0076] Step 5) According to the structural formula (EDBE)(CH3NH3) n-1 Pb n X 3n+1 Weigh 177.96 mg of lead iodide, 20.85 mg of chloromethylamine, and 31.19 mg of EDBEI2 prepared in Step 2), and dissolve them in 1 ml of the methylamine acetate solvent prepared in Step 1). Stir at 60 °C for 2 hours until completely dissolved to prepare a perovskite precursor solution with n = 5 and a concentration of 230 mg / ml. (For perovskite precursor solutions with n = 3, 4, 6, also weigh a certain amount of lead iodide, chloromethylamine, and EDBEI2 according to the concentration of 230 mg / ml and the above structural general formula).

[0077] Step 6) Treat the ITO substrate cleaned in Step 3) with ultraviolet ozone for 15 minutes.

[0078] Step 7) Take 45 μL of the hole transport material PEDOT:PSS and drop it onto the ITO substrate treated in Step 6). Use a spin coater to spin-coat a film at a rotation speed of 5000 revolutions per minute for 50 seconds, and then anneal the spin-coated PEDOT:PSS on ITO at 120 °C for 30 minutes.

[0079] Step 8) Place the ITO conductive substrate with the spin-coated hole transport layer after annealing in Step 7) on a heating spin coater and preheat for 5 minutes.

[0080] Step 9) Take 100 μL of the perovskite precursor solution prepared in step 5) and drop it onto the preheated ITO substrate in step 8), spin-coat to form a film, and then perform annealing to form a perovskite thin film. The rotation speed of spin-coating the perovskite precursor solution is 4000 revolutions per minute for 20 seconds, and anneal at 100 °C in air for 5 min.

[0081] Step 10) Spin-coat the electron transport material prepared in step 4) onto the perovskite thin film in step 9). Spin-coat PCBM at 1000 revolutions per minute for 60 seconds, and then spin-coat at 2000 revolutions per minute for 2 seconds to form an electron transport layer.

[0082] Step 11) Using vacuum evaporation technology, evaporate 1 nm of LiF onto the electron transport layer in step 10), and then evaporate 100 nm of metal electrode Al. Thus, a perovskite solar cell is fabricated.

[0083] Step 12) Under standard test conditions (AM1.5 G illumination), the device performance parameters of the low-dimensional perovskite solar cell based on the <110> orientation prepared in this example are as follows:

[0084] n = 3: The energy conversion efficiency is 9.05%, the open-circuit voltage is 1.01 V, the short-circuit current is 12.49 mA / cm 2 , and the fill factor is 71.84%;

[0085] n = 4: The energy conversion efficiency is 9.15%, the open-circuit voltage is 1.02 V, the short-circuit current is 12.49 mA / cm 2 , and the fill factor is 71.55;

[0086] n = 5: The energy conversion efficiency is 13.87%, the open-circuit voltage is 1.01 V, the short-circuit current is 18.59 mA / cm 2 , and the fill factor is 73.61%;

[0087] n = 6: The energy conversion efficiency is 11.42%, the open-circuit voltage is 1.01 V, the short-circuit current is 15.96 mA / cm 2 , and the fill factor is 70.96%;

[0088] The experimental results show that the low-dimensional perovskite based on the <110> orientation with n = 5 exhibits the optimal device performance.

[0089] The present invention is not limited to the specific technical solutions described in the above embodiments. Any technical solutions formed by equivalent substitution are within the scope of protection required by the present invention.

Claims

1. A preparation method of a low-dimensional perovskite solar cell based on <110> orientation, characterized in that, It includes the following steps: (1) Mix acetic acid and methylamine in a molar ratio of 1:1.5 and stir to prepare methylammonium acetate; (2) Dissolve lead iodide, chloromethylamine, and 2,2'-ethylenedioxy-bis(ethylammonium iodide) (EDBEI2) in the methylammonium acetate solution according to a certain stoichiometric ratio and concentration to prepare a perovskite precursor solution, and then stir at 60 °C for 6 hours; (3) Spin-coat the hole transport material on the ITO conductive glass; (4) Spin-coat the prepared perovskite precursor solution on the ITO conductive substrate with a hole transport layer, and anneal at 100 °C for 5 min to obtain a dense and uniform active layer; (5) Spin-coat the electron transport layer on the perovskite layer; (6) Vacuum deposit the modification layer and the metal electrode on the electron transport layer; The structural formula of the 2,2'-ethylenedioxy-bis-hexylamine iodide in the step (2) is NH3(CH2)2O(CH2)2O(CH2)2NH3I 2； The perovskite precursor solution in step (2) is (NH3(CH2)2O(CH2)2O(CH2)2NH3)(CH3NH3) n- 1Pb n X 3n+1 , where X represents a halogen of chlorine (Cl) and iodine (I), and n = 5.

2. The method for preparing a low-dimensional perovskite solar cell based on <110> orientation according to claim 1, wherein: In step (1), acetic acid and methylamine are stirred in an ice-water bath for 2 hours.

3. The preparation method of the low-dimensional perovskite solar cell based on <110> orientation according to claim 1, wherein: In step (2), the concentration of the perovskite precursor is 230 mg / mL.

4. The method for preparing a low-dimensional perovskite solar cell based on <110> orientation according to claim 1, wherein: The hole transport layer spin-coated on the transparent conductive ITO glass in step (3) is PEDOT:PSS, and the specific steps are as follows: (1) The spin-coating condition is to spin at 5000 rpm for 50 s, (2) After spin-coating, anneal at 120 °C for 30 minutes.

5. The preparation method of the low-dimensional perovskite solar cell based on <110> orientation according to claim 1, wherein: In step (4), spin-coating is performed on the substrate at 90 °C using the heated spin-coating method.

6. The method for preparing a low-dimensional perovskite solar cell based on <110> orientation according to claim 1, wherein: The electron transport layer spin-coated on the perovskite layer in step (5) is PCBM, and the specific steps are as follows: (1) Dissolve 18 mg of PCBM in chlorobenzene, stir overnight at 60 °C, and let it stand for later use; The spin-coating conditions are to spin at 1000 rpm for 60 s and then at 2000 rpm for 2 s.

7. The preparation method of the low-dimensional perovskite solar cell based on <110> orientation according to claim 1, wherein: In step (6), the modification layer is LiF and the metal electrode is Al, and the specific steps are as follows: The thickness of the LiF modification layer is 2 nm; The thickness of the Al metal electrode is 100 nm.

8. A solar cell prepared by the method for preparing a <110>-oriented low-dimensional perovskite solar cell according to any one of claims 1-7.

9. Application of the <110>-oriented low-dimensional perovskite solar cell according to claim 8 in the field of optoelectronics.

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