A low-cost, highly efficient and stable organic-inorganic hybrid perovskite solar cell, its preparation method and application

Abstract

The present invention relates to a low-cost, highly efficient and stable organic-inorganic hybrid methylammonium lead iodide perovskite solar cell and its preparation method and application, belonging to the field of optoelectronic materials and devices. In this invention, a PbCO3 concentration of 200-500 mg / mL is dissolved in a methylammonium acetate solvent, and it is spin-coated onto an ITO substrate with pre-deposited SnO2 by means of heating spin-coating. After annealing, a dense, uniform and stable perovskite thin film is formed, and the whole process is completely operated in air. Then, a Spiro-OMeTAD hole transport layer is spin-coated on the thin film, and a modified layer MoO3 and a metal electrode are deposited by vacuum evaporation technology to complete the preparation of the device.

Description

Technical Field

[0001] The present invention relates to a preparation method of an organic-inorganic hybrid perovskite solar cell with low cost, high efficiency and stability, in particular to a method for preparing a methylammonium perovskite solar cell by using an ionic liquid to dissolve lead carbonate and replace expensive lead iodide, belonging to the field of optoelectronic materials and technologies. Background Art

[0002] When non-renewable energy sources such as natural gas, coal, and oil are in frequent short supply and the energy problem has increasingly become a bottleneck restricting the economic development of the international community, more and more countries have begun to implement the "Sunshine Plan", develop solar energy resources, and seek new driving forces for economic development. As a clean energy source that is inexhaustible and renewable, solar energy is gradually replacing traditional fossil fuels. As one of the main ways to utilize solar energy, solar cells have attracted much attention.

[0003] Since the advent of organic-inorganic hybrid perovskite solar cells in 2009, in just a few years, the photoelectric conversion efficiency has increased from 3.8% to 25.5%. Although the photoelectric conversion efficiency of organic-inorganic hybrid perovskite solar cells has developed rapidly, there are still many problems in the process of their commercial application. First of all, due to the need to operate in a low-humidity environment and under nitrogen protection during the preparation process, and the high price of lead iodide used in the preparation of methylammonium lead iodide perovskite, the commercialization of perovskite batteries is greatly restricted. In addition, some salts containing lead ions that can replace lead iodide are poorly soluble.

[0004] Compared with lead iodide, lead carbonate is cheaper. Introducing it as a lead source into the preparation of perovskite solar cells to replace lead iodide has higher commercial value. The research of the present invention is to prepare a low-cost, high-efficiency and stable organic-inorganic hybrid perovskite solar cell with lead carbonate as the lead source in air, and explore the changes in perovskite thin films, device performance and related mechanism principles. The organic-inorganic hybrid methylammonium lead iodide perovskite solar cell prepared by lead carbonate has good performance and stability. Summary of the Invention

[0005] The technical problem solved by the present invention is: aiming at the high price of lead iodide used in methylammonium lead iodide perovskite, a low-cost, high-efficiency and stable organic-inorganic hybrid perovskite solar cell, its preparation method and application are proposed, which specifically include the following steps:

[0006] (1) Mix acetic acid and methylamine in a molar ratio of 1:1 and stir to prepare methylammonium acetate;

[0007] (2) Dissolve lead carbonate with ionic liquid methylammonium acetate to prepare a precursor solution, and spin-coat it on the electron transport layer to obtain a stable perovskite thin film;

[0008] (3) Prepare a perovskite solar cell using the perovskite thin film in step (2), which successively includes: an ITO conductive substrate, an electron transport layer, a perovskite thin film layer, a hole transport layer, a vacuum evaporation modification layer, and a metal electrode.

[0009] Preferably, it includes the following steps:

[0010] (1) Mix acetic acid and methylamine in a molar ratio of 1:1 and stir to prepare methylammonium acetate;

[0011] (2) Dissolve lead carbonate in the methylammonium acetate solvent at a concentration of 400 mg / mL to prepare a perovskite precursor solution, and then stir at 50 - 100 °C for 6 - 12 hours;

[0012] (3) Spin - coat the electron transport material on the ITO conductive glass;

[0013] (4) Spin - coat the prepared precursor solution in step (2) on the ITO conductive substrate with an electron transport layer, and anneal at 70 - 120 °C for 5 - 10 min to obtain a stable perovskite thin film;

[0014] (5) Coat a hole transport layer on the perovskite thin film layer;

[0015] (6) Vacuum - evaporate a modification layer and a metal electrode on the hole transport layer.

[0016] Preferably, in step (1), acetic acid and methylamine are stirred and reacted at a low temperature of 0 °C for 2 hours.

[0017] Preferably, the electron transport layer spin - coated on the transparent conductive ITO glass in step (3) is SnO2,

[0018] (1) The spin - coating condition is to spin at 4000 revolutions for 30 seconds;

[0019] (2) After spin - coating, anneal at 150 °C for 30 minutes.

[0020] Preferably, in step (4), spin - coating is carried out using the heating spin - coating method, and the specific steps are as follows:

[0021] (1) The substrate temperature is 50 - 100 °C;

[0022] (2) The spin - coating condition is to spin at 4000 revolutions for 20 seconds;

[0023] (3) After spin - coating, anneal at 70 - 120 °C for 5 - 10 min.

[0024] Preferably, the solution spin - coated on the upper surface of the perovskite in step (5) is the hole transport layer Spiro - OMeTAD, and the specific steps are as follows:

[0025] (1) Dissolve 73.2 mg of Spiro-OMeTAD in 1 mL of chlorobenzene;

[0026] (2) Dissolve 520 mg of lithium salt in 1 mL of acetonitrile solution;

[0027] (3) Add 17.6 μL of the lithium salt solution to the Spiro-OMeTAD solution;

[0028] (4) Add 28.8 μL of the TBP solution to Spiro-OMeTAD;

[0029] (5) Stir the mixed solution at room temperature for 2 hours;

[0030] (6) The spin-coating conditions are 3000 revolutions for 30 s;

[0031] Preferably, in step (6), the modification layer is MoO3 and the metal electrode is Ag. The specific steps are as follows:

[0032] (3) The thickness of the MoO3 modification layer is 5 nm;

[0033] (4) The thickness of the metal Au electrode is 200 nm.

[0034] To solve the above technical problems, another technical solution proposed by the present invention is: the application of the low-cost, highly efficient and stable organic-inorganic hybrid perovskite solar cell in the optoelectronic field.

[0035] Advantages of the present invention:

[0036] (1) Generally, the price of lead iodide is about 145 yuan per gram, and the price of lead carbonate is about 3 yuan per gram. The price of lead iodide is 48 times that of lead carbonate. Using lead carbonate instead of lead iodide as the lead source to prepare perovskite solar cells has lower costs and greater commercial value. Although the solubility product of lead carbonate is four orders of magnitude smaller than that of lead iodide, lead carbonate has good solubility in the ionic liquid methylammonium acetate, and the performance and stability of the prepared perovskite solar cells can be comparable to those prepared with lead iodide.

[0037] (2) Using methylammonium acetate solvent, perovskite thin films can be spin-coated in an air atmosphere, which is more convenient to operate and is conducive to the industrialization process of perovskite solar cells. The photoelectric conversion efficiency of the methylammonium lead iodide perovskite solar cell prepared with lead carbonate in air is greater than 19%.

[0038] (3) Compared with the preparation using traditional DMF / DMSO solvents, inorganic lead salts (lead carbonate, lead sulfate, and lead nitrate) can dissolve in methylammonium acetate solvent. Among them, lead carbonate has a special interaction with methylammonium acetate, enabling lead carbonate to dissolve in methylammonium acetate solvent, with a solubility reaching over 500 mg / mL. Meanwhile, the perovskite thin film prepared from lead carbonate has a dense and smooth morphology, and the perovskite device has excellent stability.

[0039] (4) High-quality, dense, and uniform methylammonium lead iodide perovskite thin films are prepared in an environment with a humidity greater than 80%, reducing the environmental requirements for the preparation method of methylammonium lead iodide perovskite thin films. The traditional DMF / DMSO solvent preparation generally requires a humidity of less than 40%. Description of the Drawings

[0040] The present invention will be further described below in conjunction with the drawings.

[0041] Figure 1 It is the SEM image of the low-cost, highly efficient, and stable perovskite thin film prepared based on lead carbonate and lead sulfate of the present invention.

[0042] Figure 2 It is the XRD pattern of the low-cost, highly efficient, and stable perovskite thin film prepared based on lead carbonate and lead sulfate of the present invention.

[0043] Figure 3 It is the UV-visible light absorption spectrum of the low-cost, highly efficient, and stable perovskite thin film prepared based on lead carbonate and lead sulfate of the present invention.

[0044] Figure 4 It is the PL image of the low-cost, highly efficient, and stable organic-inorganic hybrid perovskite solar cell prepared based on lead carbonate and lead sulfate of the present invention.

[0045] Figure 5 It is the J-V curve of the energy conversion efficiency of the low-cost, highly efficient, and stable organic-inorganic hybrid perovskite solar cell prepared based on lead carbonate and lead sulfate of the present invention.

[0046] Figure 6 It is the comparative graph of the change curve of the photoelectric conversion efficiency over time of the low-cost, highly efficient, and stable organic-inorganic hybrid perovskite solar cell prepared based on lead carbonate and lead sulfate of the present invention under nitrogen protection.

[0047] Figure 7 It is the figure of the low-cost, highly efficient, and stable organic-inorganic hybrid perovskite thin film prepared based on lead nitrate of the present invention.

[0048] Figure 8 It is the schematic diagram of the device structure of the low-cost, highly efficient, and stable organic-inorganic hybrid perovskite solar cell prepared by the present invention. Detailed Embodiments

[0049] Example 1

[0050] This example is a low-cost, highly efficient and stable organic-inorganic hybrid perovskite solar cell of the present invention. To fully understand the present invention, the experimental humidity condition is greater than 80%. It mainly includes the following steps:

[0051] Step 1) Take 90 mL of methylamine and place it in a round-bottom flask and stir at zero degrees Celsius.

[0052] Step 2) Place 27.6 mL of acetic acid solution in a 50 mL beaker.

[0053] Step 3) Slowly add the solution of Step 2) to the solution of Step 1), stir at zero degrees Celsius for 2 hours, and then rotary evaporate to obtain methylammonium acetate.

[0054] Step 4) Clean the ITO conductive glass in the order of ethanol, cleaning agent, ultrapure water, and acetone. Ultrasonic each in ethanol for 15 min, dry with nitrogen, and dry in an oven at 100 °C for 30 minutes to obtain a clean ITO substrate.

[0055] Step 5) Weigh 172.2 mg of lead carbonate and 308.4 mg of methylammonium iodide and completely dissolve them in 1 ml of methylammonium acetate solvent, stir at 50 - 100 °C for 10 hours, and its concentration reaches 400 mg / mL.

[0056] Step 6) Treat the cleaned ITO substrate in Step 4) with ultraviolet ozone for 15 minutes.

[0057] Step 7) Dissolve 73.2 mg of Spiro-OMeTAD in 1 mL of chlorobenzene; dissolve 520 mg of lithium salt in 1 mL of acetonitrile solution; add 17.6 μL of the lithium salt solution to the Spiro-OMeTAD solution; add 28.8 μL of the TBP solution to the Spiro-OMeTAD;

[0058] Stir the mixed solution at room temperature for 2 hours; the spin coating condition is 3000 revolutions for 30 s;

[0059] Step 8) Take 40 μL of the electron transport material SnO2 and drop it onto the ITO substrate treated in Step 6), use a spin coater to spin coat into a film, spin at a speed of 4000 revolutions per minute for 30 seconds, and then anneal the ITO spin-coated with SnO2 at 150 °C for 30 minutes.

[0060] Step 9) Place the ITO conductive substrate spin-coated with the electron transport layer after annealing in Step 8) on a heating spin coater and preheat for 5 min.

[0061] Step 10) Take 100 μL of the perovskite precursor solution prepared in Step 5) and drop it onto the preheated ITO substrate in Step 9), 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.

[0062] Step 11) Spin-coat the hole transport material prepared in Step 7) onto the perovskite thin film in Step 10). Spin-coat Spiro-OMeTAD at 3000 revolutions per minute for 30 seconds to form a hole transport layer.

[0063] Step 13) Use vacuum evaporation technology to evaporate 5 nm of MoO3 onto the hole transport layer in Step 11), and then evaporate 200 nm of metal electrode Ag. Thus, a perovskite solar cell is fabricated.

[0064] Step 14) Under standard test conditions (AM1.5G illumination), the device performance parameters of the low-cost, highly efficient and stable organic-inorganic hybrid perovskite solar cell prepared in this example are as follows: the energy conversion efficiency is 19.40%, the open-circuit voltage is 1.09 V, and the short-circuit current is 23.52 mA / cm 2 , and the fill factor is 75.58%;

[0065] Comparative Example 1

[0066] This example is a low-cost, highly efficient and stable organic-inorganic hybrid perovskite solar cell of the present invention for better understanding of the present invention. It is basically the same as Example 1, except that in Step 5), lead carbonate is replaced by lead sulfate, and 144.6 mg of lead sulfate and 228.2 mg of methylammonium iodide are weighed, and the concentration reaches 300 mg / mL. The device performance parameters of the perovskite solar cell are as follows: the energy conversion efficiency is 12.44%, the open-circuit voltage is 1.08 V, and the short-circuit current is 20.19 mA / cm 2 , and the fill factor is 57.08%. The device performance of the perovskite cell is inferior to that prepared with lead carbonate.

[0067] Comparative Example 2

[0068] This example is a low-cost, highly efficient and stable organic-inorganic hybrid perovskite solar cell of the present invention for better understanding of the present invention. It is basically the same as Example 1, except that in Step 5), lead carbonate is replaced by lead nitrate, and 160.1 mg of lead nitrate and 231.3 mg of methylammonium iodide are weighed. A perovskite thin film can be prepared, but the film is too frosted, and when made into a device, the efficiency is almost zero.

[0069] Comparative Example 3

[0070] The preparation of methylammonium lead iodide perovskite thin films using traditional DMF / DMSO solvents requires operation in a vacuum glove box, which has high environmental requirements. Moreover, lead carbonate has extremely low solubility in traditional DMF / DMSO solvents, making it impossible to prepare perovskite thin films.

[0071] 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 method for a low-cost, highly efficient and stable organic-inorganic hybrid methylammonium lead iodide perovskite solar cell, characterized in that, It includes the following steps: Step (1): Take 90 mL of methylamine and place it in a round-bottom flask, stirring at zero degrees Celsius; Step (2): Place 27.6 mL of acetic acid solution in a 50 mL beaker; Step (3): Slowly add the solution in Step (2) to the solution in Step (1), stir at zero degrees Celsius for 2 hours, and then perform rotary evaporation to obtain methylammonium acetate; Step (4): Clean the ITO conductive glass in the order of ethanol, cleaning agent, ultrapure water, and acetone. Ultrasonic each in ethanol for 15 min, dry with nitrogen, and place in an oven at 100 °C for 30 minutes to obtain a clean ITO substrate; Step (5): Weigh 172.2 mg of lead carbonate and 308.4 mg of methylammonium iodide and completely dissolve them in 1 ml of methylammonium acetate solvent, stir at 50 - 100 °C for 10 hours; Step (6): Subject the cleaned ITO substrate in Step (4) to ultraviolet ozone treatment for 15 minutes; Step (7): Dissolve 73.2 mg of Spiro-OMeTAD in 1 mL of chlorobenzene to form a Spiro-OMeTAD solution; dissolve 520 mg of lithium salt in 1 mL of acetonitrile solution to form a lithium salt solution; add 17.6 μL of the lithium salt solution to the Spiro-OMeTAD solution to form Spiro-OMeTAD; Add 28.8 μL of the TBP solution to Spiro-OMeTAD to form a mixed solution; stir the mixed solution at room temperature for 2 hours; the spin-coating condition is to spin-coat at 3000 revolutions per minute for 30 s; Step (8): Take 40 μL of the electron transport material SnO2 and drop it onto the ITO substrate treated in Step (6), use a spin coater to spin-coat into a film, with a rotation speed of 4000 revolutions per minute for 30 seconds, and then anneal the ITO spin-coated with SnO2 at 150 °C for 30 minutes; Step (9): Place the ITO conductive substrate spin-coated with the electron transport layer completed in Step (8) on a heating spin coater and preheat for 5 min; Step (10): Take 100 μL of the perovskite precursor solution prepared in Step (5) and drop it onto the ITO substrate preheated in Step (9), spin-coat into a film, and then perform annealing to form a perovskite film; the rotation speed of spin-coating the perovskite precursor solution is 4000 revolutions per minute for 20 seconds, and anneal in air at 100 °C for 5 min; Step (11): Spin-coat the hole transport material prepared in Step (7) onto the perovskite film in Step (10), spin-coat Spiro-OMeTAD at 3000 revolutions per minute for 30 seconds to form a hole transport layer; Step (12): Adopt vacuum evaporation technology to evaporate 5 nm of MoO3 on the hole transport layer in Step (11), and then evaporate 200 nm of metal electrode Ag. Thus, a perovskite solar cell is fabricated. In step (13), under AM1.5G illumination under standard test conditions, the performance parameters of the prepared low-cost, highly efficient and stable organic-inorganic hybrid perovskite solar cell device are as follows: the energy conversion efficiency is 19.40%, the open-circuit voltage is 1.09 V, and the short-circuit current is 23.52 mA / cm 2 , and the fill factor is 75.58%.

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