CN116782681B - An inversion perovskite solar cell and its preparation method - Google Patents

Abstract

The invention relates to an inversion perovskite solar cell and a preparation method thereof. The inversion perovskite solar cell includes a perovskite film layer. The perovskite film layer material includes a perovskite material and an additive. The calcium Titanium material is a component that forms perovskite ABX ₃ , in which A is an organic/inorganic cation, B is a metal ion, and X is a halogen group; the additive is [4-(trifluoromethyl)phenyl]methyl Phosphonic acid. This inversion perovskite solar cell adds additives to the perovskite film layer, and anchors the additive materials to the perovskite grain boundaries and surface defects, effectively passivating the perovskite grain boundaries and surface defects, and The recombination center of deep energy level defects is reduced, thereby improving the efficiency of the battery and enhancing the stability of the battery.

Description

An inversion perovskite solar cell and its preparation method

Technical field

The present invention relates to a perovskite solar cell, in particular to an inversion perovskite solar cell and a preparation method thereof.

Background technique

Perovskite solar cells have received widespread attention in recent years due to their high power conversion efficiency and low manufacturing cost. Among them, the inverse structure (p-i-n) perovskite battery has a simpler device structure, lower preparation temperature and cost than the positive structure (n-i-p), and is suitable for industrial development. The efficiency loss of inversion cells mainly comes from unideal perovskite grain boundaries and interfaces, especially the interface between perovskite and the electron transport layer. For example, in inversion batteries, the interface formed between fullerene and its derivatives electron transport materials and perovskite has a large recombination loss, which greatly reduces the voltage of the battery and hinders the transmission of current. For inversion batteries, designing appropriate perovskite bulk phases and surface passivators can reduce the density of defect states at grain boundaries and surface interfaces, reduce carrier recombination at grain boundaries and interfaces, and improve the efficiency of inversion batteries. and stability, which is conducive to the further industrialization of inverted perovskite cells and is of great significance to the development of the entire photovoltaic industry.

Contents of the invention

In order to improve the efficiency and stability of inverted perovskite solar cells, the present invention provides an inverted perovskite solar cell and a preparation method thereof. The inverted perovskite solar cell adds additives to the perovskite film layer. By anchoring the additive material to the perovskite grain boundaries and surface defects, the perovskite grain boundaries and surface defects are effectively passivated, and the recombination centers of deep energy level defects are reduced, thereby improving the efficiency of the battery and enhancing the Battery stability.

Based on the above problems, one aspect of the present invention provides an inversion perovskite solar cell, including a substrate, a hole transport layer, a perovskite film layer, an electron transport layer and an electrode layer that are stacked in sequence. Additives are also provided in the mineral film layer, and the perovskite additive material is [4-(Trifluoromethyl)phenyl methyl phosphonic acid). [4-(Trifluoromethyl)phenyl]methylphosphonic acid is used as an additive material to stay on the grain boundaries and surface of the perovskite film layer, forming a thin additive layer at the grain boundaries and surface of the perovskite film. The phosphate groups can combine with uncoordinated lead defects and eliminate deep energy level defects between the band gaps such as Pb _I and Pb _i . At the same time, the formed additive layer forms a transmission channel at the interface between the perovskite and the electron transport layer. , accelerate the extraction of electrons and reduce non-radiative recombination.

As a preferred way, the molar ratio of [4-(trifluoromethyl)phenyl]methylphosphonic acid to perovskite ABX ₃ is (0.01-1)%. If it is lower than this range, it cannot effectively treat Defects are passivated. If it is higher than this range, it will lead to the accumulation of additives, affecting carrier transmission, resulting in a reduction in fill factor and current.

As a preferred way, the perovskite material includes component a and component b. The component a is one component of lead iodide or lead bromide or a combination of the two components. Component b is a component selected from cesium iodide, rubidium iodide, formamidine iodine, formamidine bromide, formamidine chloride, methylamine iodine, methylamine bromide, methylamine chloride, cesium chloride, and cesium bromide, or A combination of multiple components.

As a preferred way, the preparation method of the perovskite film layer is:

a Mix component a, component b and component c, and deposit on the hole transport layer after mixing. The deposition method is one of spin coating and blade coating; component a is one of lead iodide and lead bromide. One component or a combination of two components, component b is cesium iodide, rubidium iodide, formamidine iodine, formamidine bromide, formamidine chloride, methylamine iodine, methylamine bromide, methylamine chloride, chlorine One component or a combination of multiple components among cesium chloride and cesium bromide, component c is [4-(trifluoromethyl)phenyl]methylphosphonic acid;

b Assisted crystallization film formation: A wet film is formed after the deposition. The film formation method is vacuum drying, anti-solvent dripping, and air knife curing. One or more combinations;

c After forming a wet film, perform heating and annealing to evaporate the residual solvent and promote the crystallization of the perovskite film layer; it is prepared. The valence band top of the perovskite film material obtained by this preparation method is lower than the HOMO energy level of the hole transport material, and the conduction band top is higher than the LUMO energy level of the electron transport material, which is conducive to the transfer of electrons from the perovskite film layer to the electronic layer .

As a preferred way, the B is Pb ²⁺ .

As a preferred method, the perovskite material and the additive are prepared as a mixed solution and then coated on the hole transport layer. The coating method is spin coating, the spin coating rate is 4000-5000 rpm, and the spin coating time is 30 ~55s, add chlorobenzene solution dropwise during the spin coating process.

As a preferred way, the preparation method of the perovskite film layer is:

a Preparation of perovskite film solution: Prepare a mixed solution of lead iodide, formamidinium iodide, and methylamine chloride, and add the additive [4-(trifluoromethyl)phenyl]methylphosphonic acid to it. The additive is relatively calcium The molar ratio of titanium ABX ₃ is 0.01%; b Spin-coat the prepared perovskite film solution on the hole transport layer, the spin-coating rate is 4000rpm, the spin-coating time is 35s, and the reaction solution is added dropwise during spin-coating Solvent chlorobenzene 0.6mL, then anneal in the air at 140°C for 25 minutes, control the humidity at 30-40%, cool after annealing and set aside.

As a preferred way, the hole transport layer is provided on the substrate, and the hole transport layer material is nickel oxide (NiOx), poly[bis(4-phenyl)(2,4,6-tris) Methylphenyl)amine] (PTAA), [2-(9H-carbazol-9-yl)ethyl]phosphonic acid (2PACz), [2-(3,6-diphenyl-9H-carbazole- 9-yl)ethyl]phosphate (Me-2PACz), 4-(3,6-dimethyl-9H-carbazol-9-yl)butyl]phosphate (Me-4PACz), (2-(3, 6-dimethoxy-9H-carbazol-9-yl)ethyl)phosphonic acid (MeO-2PACz), one or more mixture materials or several laminate materials. This type of material not only has high hole transmission efficiency, but also cooperates with lead iodide, formamidine iodine, and methylamine chloride as perovskite film layer materials to reduce the energy barrier during hole injection and improve hole injection efficiency.

As a preferred method, the hole transport layer is produced by vacuum deposition or solution deposition. Vacuum deposition is preferred, which is beneficial to obtaining a dense and pure hole transport layer.

As a preferred way, the hole transport layer is prepared by: spin-coating the MeO-2PACz solution on the ITO substrate at a spin-coating rate of 3000 rpm for 30 s, and then annealing at 110°C for 15 min. Film formation at a rate and time is conducive to the uniformity of film formation, ensuring the thickness of the film layer, and obtaining a hole transport layer with a uniform film layer. The MeO-2PACz solution is obtained by mixing 0.55 mg of MeO-2PACz with 1 mL of absolute ethanol solution and filtering with a 0.45 μm filter element.

As a preferred way, the hole transport layer is prepared by spin-coating the NiO _x solution on the UV-treated ITO substrate at a spin-coating rate of 3000 rpm for 30 s, and then annealing at 130°C for 30 min. After cooling, the filtered Me-4PACz solution was spin-coated on the NiO _x substrate at a spin-coating speed of 4000 rpm for 30 s, and then annealed at 100°C for 10 min. The NiO _x solution is obtained by mixing 25 mg of NiO _x powder with 1 mL of deionized water, stirring at room temperature for 0.5 hours, and filtering with a 0.45 μm filter element. The Me-4PACz solution is obtained by mixing 0.7 mg of Me-4PACz with 1 mL of anhydrous isopropyl alcohol, stirring to dissolve, and then filtering with a 0.45 μm filter element.

As a preferred way, the hole transport layer is prepared by: dissolving 0.55 mg of MeO-2PACz powder in 1 mL of absolute ethanol to obtain solution A; dissolving 0.65 mg of 2PACz powder in 1 mL of absolute ethanol. Obtain solution B from The coating rate is 3000 rpm and the time is 30 s, followed by annealing at 100°C for 10 min.

As a preferred way, the preparation method of the perovskite film layer is: a. Prepare a perovskite film layer solution: a mixed solution of cesium iodide, methylamine bromide, formamidine iodine, lead iodide and lead bromide, and add it to Add the additive [4-(trifluoromethyl)phenyl]methylphosphonic acid, the molar ratio of the additive to the perovskite is 0.1%; b. Spin-coat the prepared perovskite film solution on the hole transport layer , the speed is 4000rpm and the time is 40s. During the spin coating process, 0.4mL of anti-solvent chlorobenzene is added dropwise to the film layer, and then annealed at 100°C for 10 minutes. After cooling, it is ready for use. On the one hand, chlorobenzene can be added dropwise during spin coating. It effectively prevents the anisotropic and irregular growth of perovskite, allowing it to nucleate uniformly, thereby achieving uniform coating. On the other hand, it can prevent the perovskite film solution from being destroyed.

As a preferred way, the preparation method of the perovskite film layer is: a. Prepare the perovskite film layer solution: a mixed solution of formamidine iodine, cesium chloride, lead iodide and methylamine chloride, and add additives to the mixed solution [4-(Trifluoromethyl)phenyl]methylphosphonic acid, the molar ratio of the additive to the perovskite material is 1%; b. Spin-coat the prepared perovskite solution on the hole transport layer, and spin The speed is 4500 rpm, and the spin coating time is 40 s. During the spin coating, 0.55 mL of anti-solvent chlorobenzene is added dropwise to the film layer, and then annealed in the air at 150°C for 15 min, and the humidity is controlled at 30 to 45%.

As a preferred way, the electron transport layer is deposited on the perovskite film layer, and the material of the electron transport layer is tin oxide, titanium oxide, zinc oxide, fullerene (C ₆₀ ), fullerene derivatives At least one of the materials; preferably fullerene, which is combined with (2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl)phosphonic acid (2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl) as the hole transport layer material. MeO-2PACz) cooperates with each other to balance the hole transfer rate and electron transfer rate, and the holes and electrons can be exported to the external circuit for utilization.

As a preferred method, the preparation method of the electron transport layer is vacuum deposition or solution deposition; vacuum deposition is preferred. This deposition method can not only obtain a dense and uniform film layer, but also form a good contact interface and increase the electron transmission efficiency.

As a preferred method, the electron transport layer is made by evaporating C ₆₀ material on the perovskite modified film layer using thermal evaporation.

As a preferred way, a hole blocking layer is provided between the electron transport layer and the electrode layer, and the hole blocking layer material is 2,9-dimethyl-4,7-diphenyl-1, 10-phenanthroline. More preferably, the hole blocking layer is evaporated and deposited on the electron transport layer by thermal evaporation.

On the other hand, the present invention provides a method for preparing an inversion perovskite solar cell, which includes the following steps:

Preparing a hole transport layer: the hole transport layer is provided on a transparent conductive substrate;

Preparing a perovskite film layer: the perovskite film layer is arranged on the hole transport layer, the perovskite film layer material includes a perovskite material and additives, and the perovskite material is to form a perovskite structure The components of ABX ₃ , where A is an organic/inorganic cation, B is a metal ion, and X is a halogen group; the additive is [4-(trifluoromethyl)phenyl]methylphosphonic acid;

Preparing an electron transport layer: the electron transport layer is arranged on the perovskite film layer;

Prepare electrode layer.

As a preferred way, the molar ratio between the additive material and the perovskite ABX ₃ is (0.01-1)%. The perovskite material is formed by the reaction of component a and component b. The component a is one component or a combination of two of lead iodide and lead bromide, component b is cesium iodide, rubidium iodide, formamidine iodine, methylamine iodine, methylamine bromide, methylamine chloride, chlorine A component or a combination of components in cesium chloride.

As a preferred way, a hole blocking layer is provided between the electron transport layer and the electrode layer, and the hole blocking layer satisfies one or a combination of the following:

—The hole blocking layer material is 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline:

—The hole blocking layer is evaporated and coated on the electron transport layer using thermal evaporation or solution deposition is used to form the film layer;

The preparation step of the hole blocking layer is arranged between the electron transport layer and the electrode layer.

The beneficial effects produced by the present invention include:

The present invention is designed for inverse perovskite batteries (p-i-n type). Compared with positive perovskite batteries (n-i-p), although the preparation temperature is low and the cost is low, it will be affected by the perovskite grain boundaries and There are many defects in the interface structure, especially the large interface recombination loss between the perovskite and the electron transport layer, which makes the battery transmission efficiency low.

In the present invention, the additive [4-(trifluoromethyl)phenyl]methylphosphonic acid material is introduced into the perovskite film layer to modify the perovskite film layer, between the grain boundary and the surface interface of the perovskite film layer A thin layer of finishing material is inserted. On the one hand, the phosphates in the material can anchor vacancy defects and uncoordinated lead on the surface of the perovskite, effectively passivating the defects of the perovskite, especially the deep level defects, reducing carrier recombination center. On the other hand, the -CF ₃ group in [4-(trifluoromethyl)phenyl]methylphosphonic acid has strong electronegativity, ensuring that the modified material has strong molecular polarity, making it stable against defect formation. The binding force is conducive to further improving the defect passivation effect. On the other hand, the material forms a transmission channel between the perovskite and the electron transport layer, accelerates the extraction of electrons, and prevents direct contact between the perovskite and the electron transport material to a certain extent, preventing the diffusion of halogen at the interface. Form defects to improve photoelectric performance and stability. Furthermore, after adding the additive [4-(trifluoromethyl)phenyl]methylphosphonic acid, the present invention can effectively reduce the defect state density of the film layer and improve the stability and photoelectric conversion efficiency. Compared with untreated perovskite cells, The absolute efficiency has been increased by 3.63%, and the light stability has been greatly improved.

Description of the drawings

Figure 1 is a current-voltage curve diagram of Example 1 and Comparative Example 1;

Figure 2 is a current-voltage curve diagram of Example 2 and Comparative Example 2;

Figure 3 is the efficiency-light time attenuation curve diagram of Example 2 and Comparative Example 2;

Figure 4 is the efficiency-heating time decay curve of Example 3 and Comparative Example 3.

Detailed ways

The present invention will be explained in further detail below with reference to the accompanying drawings and specific embodiments. However, it should be understood that the protection scope of the present invention is not limited by the specific embodiments. It is worth mentioning that the precursor solution involved in the following examples can be It is prepared in the S01 step, or it can be prepared at any time before the corresponding film layer is coated.

Example 1

A method for preparing an inversion perovskite solar cell, including the following steps

Preparation of S01 precursor solution:

a Perovskite film layer solution: a mixed solution of lead iodide (PbI ₂ ), formamidinium iodide (FAI), methylamine chloride (MACl) and additives;

(1) PbI ₂ and FAI are dissolved in a mixed solution of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) at a molar ratio of 1.05:1, where the volume ratio of DMF to DMSO is 4 :1;

(2) Add MACl to the solution to form a mixed solution. The mass fraction of MACl in the mixed solution is 33%. The concentration of FAPbI ₃ in the mixed solution is 45wt%. FAPbI ₃ is calculated based on the equimolar formation of PbI ₂ ;

(3) Add [4-(trifluoromethyl)phenyl]methylphosphonic acid to the solution, the molar ratio of [4-(trifluoromethyl)phenyl]methylphosphonic acid to FAPbI ₃ is 0.01%, FAPbI ₃ is formed from equimolar amounts of PbI ₂ ;

(4) Heat the solution to 60°C and stir for 60 minutes until completely dissolved;

(5) Use a 0.22μm filter element to filter the solution to remove large particulate matter in the solution. The filtered solution will be used for later use.

b Hole transport layer solution: MeO-2PACz/absolute ethanol solution;

Mix 0.55 mg of MeO-2PACz with 1 mL of ethanol solution, and use a 0.45 μm filter element to filter to remove large particulate matter. The filtered solution is set aside for later use.

Pretreatment of S02 substrate:

The ITO glass substrate was first ultrasonically cleaned in deionized water for 30 minutes, then in acetone for 30 minutes, and finally in isopropyl alcohol (IPA) for 30 minutes, then dried with a nitrogen gun and placed in a UV ozone processor Process in medium for 30 minutes and set aside.

Preparation of S03 hole transport layer:

The hole transport layer solution was spin-coated on the ITO substrate at a spin-coating rate of 3000 rpm for 30 s, and then annealed at 110°C for 15 min to obtain a hole transport layer.

Preparation of S04 perovskite film layer:

Spin-coat the prepared perovskite solution on the hole transport layer at a spin-coating speed of 4000 rpm. At the 15th second of spin-coating, drop 0.6 mL of anti-solvent chlorobenzene on the film layer, and then continue to spin-coat. Spin coat for 35 seconds.

After spin coating, anneal in the air at 140°C for 25 minutes, and the humidity is controlled at 30 to 40%.

Preparation of S05 electron transport layer:

Use vacuum evaporation equipment to evaporate the C ₆₀ material using thermal evaporation to form a 25nm electron transport layer on the perovskite modified film layer. The evaporation vacuum degree is below 7*10 ^-4 Pa.

Preparation of S06 hole blocking layer:

Use vacuum evaporation equipment to evaporate the BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline) material by thermal evaporation to form an 8 nm hole on the electron transport layer. Hole barrier layer, evaporation vacuum degree is below 7*10 ^-4 Pa.

Preparation of S07 electrode:

Use vacuum evaporation equipment to evaporate 150nm copper (Cu) as an electrode on the surface of BCP using thermal evaporation. The evaporation vacuum degree is below 7*10 ^-4 Pa.

Comparative example 1

The difference from Example 1 is that no additives are placed in the perovskite film layer. The preparation method includes the following steps:

Preparation of S01 precursor solution

a Perovskite film layer solution: a mixed solution of lead iodide (PbI ₂ ), formamidinium iodide (FAI), and methylamine chloride (MACl);

(1) PbI ₂ and FAI are dissolved in a mixed solution of DMF and DMSO at a molar ratio of 1.05:1, where the volume ratio of DMF to DMSO is 4:1;

(2) Add MACl to the solution to form a mixed solution. The mass fraction of MACl in the mixed solution is 33%. The concentration of FAPbI ₃ in the mixed solution is 45wt%. FAPbI ₃ is calculated based on the equimolar formation of PbI ₂ ;

(3) Heat the solution to 60°C and stir for 60 minutes until completely dissolved;

(4) Use a 0.22μm filter element to filter the solution to remove large particulate matter in the solution. The filtered solution is ready for use.

b Hole transport layer solution: MeO-2PACz/ethanol solution;

Mix 0.55 mg of MeO-2PACz with 1 mL of ethanol solution, and use a 0.45 μm filter element to filter to remove large particulate matter. The filtered solution is set aside for later use.

Pretreatment of S02 substrate:

The ITO glass substrate was first ultrasonically cleaned in deionized water for 30 minutes, then in acetone for 30 minutes, and finally in isopropyl alcohol (IPA) for 30 minutes, then dried with a nitrogen gun and placed in a UV ozone processor Process in medium for 30 minutes and set aside.

Preparation of S03 hole transport layer:

The filtered MeO-2PACz solution was spin-coated on the ITO substrate at a spin-coating speed of 3000 rpm for 30 s, followed by annealing at 110°C for 15 min.

Preparation of S04 perovskite film layer:

Spin-coat the prepared solution of lead iodide, formamidine iodine, and methylamine chloride on the MeO-2PACz film layer. The spin-coating speed is 4000 rpm for 35 seconds. During the 15th second of spin-coating, add dropwise to the film layer. Antisolvent chlorobenzene 0.6mL.

After spin coating, anneal in the air at 140°C for 25 minutes, and the humidity is controlled at 30-40%.

Preparation of S05 electron transport layer:

Use vacuum evaporation equipment to evaporate the C ₆₀ material using thermal evaporation to form a 25nm electron transport layer on the perovskite modified film layer. The evaporation vacuum degree is below 7*10 ^-4 Pa.

Preparation of S06 hole blocking layer:

Use vacuum evaporation equipment to evaporate the BCP material by thermal evaporation to form an 8nm hole blocking layer on the electron transport layer. The evaporation vacuum degree is below 7*10 ^-4 Pa.

Preparation of S07 electrode:

Use vacuum evaporation equipment to evaporate 150nm copper (Cu) as an electrode on the surface of BCP using thermal evaporation. The evaporation vacuum degree is below 7*10 ^-4 Pa.

The current and voltage of the perovskite solar cells obtained in Example 1 and Comparative Example 1 were monitored and plotted as a curve graph, as shown in Figure 1, with the additive [4-(trifluoromethyl)phenyl]methylphosphine The absolute efficiency of the acid-based perovskite battery is 3.63% higher than that of the battery without additives, and it shows obvious advantages in open circuit voltage, short circuit current, filling factor and conversion efficiency. See Table 1 for details.

Table 1 Optoelectronic parameters of conventional band gap (1.56eV) perovskite cells with and without additives

Example 2

A method for preparing an inversion perovskite solar cell is:

Preparation of S01 precursor solution:

aPerovskite film layer solution

22.0 mg of cesium iodide, 28.5 mg of methylamine bromide, 233.9 mg of formamidine iodine, 548.6 mg of lead iodide, and 187.2 mg of lead bromide were dissolved in 1 mL of a mixed solution of DMF and DMSO. The volume ratio is 6:1, heat to 60°C, stir for 1 hour to fully dissolve the solution, and filter using a 0.22 μm filter element. The filtered solution is ready for use. Add [4-(trifluoromethyl)phenyl to the solution ] methylphosphonic acid, the molar ratio of [4-(trifluoromethyl)phenyl]methylphosphonic acid to the final perovskite FAPbI ₃ is 0.1%, and FAPbI ₃ is formed by equal moles of PbI ₂ .

b hole transport layer solution

Mix 25 mg of NiO _x powder with 1 mL of deionized water, stir at room temperature for 0.5 hours, use a 0.45 μm filter element to filter to remove large particles in the solution, and obtain a NiO _x solution after filtration for later use.

Mix 0.7 mg of Me-4PACz with 1 mL of anhydrous IPA, stir to dissolve, and then filter with a 0.45 μm filter element to obtain a Me-4PACz solution for later use.

Pretreatment of S02 substrate:

The ITO glass substrate was first ultrasonically cleaned in deionized water for 30 minutes, then in acetone for 30 minutes, and finally in isopropyl alcohol (IPA) for 30 minutes, then dried with a nitrogen gun and placed in a UV ozone processor Process in medium for 30 minutes and set aside.

Preparation of S03 hole transport layer:

The filtered NiO _x solution was spin-coated on the UV-treated ITO substrate at a spin-coating rate of 3000 rpm and a spin-coating time of 30 s, followed by annealing at 130°C for 30 min.

After the film layer is cooled, the Me-4PACz solution is spin-coated on the NiO _x substrate at a spin-coating speed of 4000 rpm and a spin-coating time of 30 s, followed by annealing at 100°C for 10 min.

Preparation of S04 perovskite film layer:

Spin-coat the prepared perovskite film solution on the hole transport layer at a spin-coating rate of 4000 rpm and a spin-coating time of 40 seconds. At the 18th second of spin-coating, drop 0.4 mL of the antisolvent chlorobenzene on the film layer. , then annealed at 100°C for 10 min, cooled and set aside.

Preparation of S05 electron transport layer:

Use vacuum evaporation equipment to evaporate the C ₆₀ material using thermal evaporation to form a 25nm electron transport layer on the perovskite modification layer. The evaporation vacuum degree is below 7*10 ^-4 Pa.

Preparation of S06 hole blocking layer:

Use vacuum evaporation equipment to evaporate the BCP material by thermal evaporation to form an 8nm hole blocking layer (BCP film layer) on the electron transport layer. The evaporation vacuum degree is below 7*10 ^-4 Pa.

Preparation of S07 electrode:

Use vacuum evaporation equipment to evaporate 120nm thick silver (Ag) as an electrode on the surface of the BCP film layer using thermal evaporation. The evaporation vacuum degree is below 7*10 ^-4 Pa.

Comparative example 2

The difference from Example 2 is that no additives are added to the perovskite precursor solution. Specific steps include:

Preparation of S01 precursor solution:

aPerovskite layer solution

22mg cesium iodide, 28.5mg methylamine bromide, 233.9mg formamidine iodine, 548.6mg lead iodide, 187.2mg lead bromide were dissolved in 1mL of a mixed solution of DMF and DMSO, the volume of DMF and DMSO The ratio is 6:1, heat to 60°C, stir for 1 hour to fully dissolve the solution, and filter with a 0.22 μm filter element. The filtered solution is ready for use.

b hole transport layer solution

Mix 25 mg of NiO _x powder with 1 mL of deionized water, stir at room temperature for 0.5 hours, filter with a 0.45 μm filter element and set aside. Mix 0.7 mg of Me-4PACz with 1 mL of anhydrous IPA, stir to dissolve, then filter with a 0.45 μm filter element and set aside.

Pretreatment of S02 substrate:

The ITO glass substrate was first ultrasonically cleaned in deionized water for 30 minutes, then in acetone for 30 minutes, and finally in isopropyl alcohol (IPA) for 30 minutes, then dried with a nitrogen gun and placed in a UV ozone processor Process in medium for 30 minutes and set aside.

Preparation of S03 hole transport layer:

The filtered NiO _x solution was spin-coated on the UV-treated ITO substrate at a spin-coating rate of 3000 rpm for 30 s, followed by annealing at 130°C for 30 min. After cooling, the filtered Me-4PACz solution was spin-coated on the NiO _x substrate at a spin-coating speed of 4000 rpm for 30 s, and then annealed at 100°C for 10 min.

Preparation of S04 perovskite film layer:

The prepared perovskite solution was spin-coated on the Me-4PACz film layer at a speed of 4000 rpm and a time of 40 seconds. At the 18th second of spin coating, 0.4 mL of the anti-solvent chlorobenzene was added dropwise to the film layer, and then heated at 100°C. Anneal for 10 minutes, cool and set aside.

Preparation of S05 electron transport layer:

Use vacuum evaporation equipment to evaporate 25nm of C ₆₀ material using thermal evaporation method, and the vacuum degree is below 7*10 ^-4 Pa.

Preparation of S06 hole blocking layer:

Use vacuum evaporation equipment to evaporate 8nm of BCP material by thermal evaporation, and the vacuum degree is below 7*10 ^-4 Pa.

Preparation of S07 electrode:

Use vacuum evaporation equipment to evaporate 120nm silver (Ag) as an electrode on the surface of BCP using thermal evaporation. The vacuum degree is below 7*10 ^-4 Pa.

By testing the stability and efficiency of the batteries of Example 2 and Comparative Example 2 under light conditions, as shown in Figures 2 and 3, it can be seen from Figure 2 that the open circuit voltage of Example 2 is 1.22V, and the open circuit voltage of Comparative Example 2 is 1.22V. is 1.16V, an increase of 0.06V. The increase in voltage comes from the reduction of non-radiative recombination, indicating that Example 2 has fewer defects compared to Comparative Example 2. Since illumination can reduce the migration energy of ions and the formation energy of defects, as the illumination proceeds, the defects and ion migration intensity inside the material increase, causing internal reactions in the material, such as reactions between halogen and electrodes. This increases carrier recombination and reduces efficiency. As can be seen from Figure 3, the efficiency of Example 2 remains above 95% after the irradiation time reaches 650h, and the efficiency of Comparative Example 2 drops below 90% after the irradiation time reaches 650h, indicating that Example 2 has better illumination than Comparative Example 2. Stability has been greatly improved. Electrical monitoring of the wide bandgap (1.68eV) perovskite cells in Example 2 and Comparative Example 2 showed that the perovskite cells with additives showed significant improvements in open circuit voltage, short circuit current, filling factor and conversion efficiency. Advantages, see Table 2 for details.

Table 2 Optoelectronic parameters of perovskite cells with and without additives

Example 3

A method for preparing an inversion perovskite solar cell:

Preparation of S01 precursor solution:

aPerovskite film layer solution

Dissolve 300 mg of formamidine iodide, 870 mg of lead iodide, 2 mg of cesium chloride, and 8 mg of methylamine chloride in 800 μL of DMF and 200 μL of DMSO to form a mixed solution, and add [4-(trifluoromethyl ) phenyl]methylphosphonic acid, so that the molar ratio of [4-(trifluoromethyl)phenyl]methylphosphonic acid to lead iodide (PbI ₂ ) is 1%;

Stir at 60°C for 1 hour, filter with a 0.22 μm filter element, and take the filtrate for later use.

b hole transport layer solution

Dissolve 0.55 mg of MeO-2PACz powder in 1 mL of absolute ethanol to obtain solution A;

Dissolve 0.65 mg of 2PACz ((2-(9H-carbazol-9-yl)ethyl)phosphonic acid) powder in 1 mL of absolute ethanol to obtain solution B;

Mix solution A and solution B according to a volume ratio of 1:3, shake and stir, and filter with a 0.45 μm filter element, and take the filtrate for later use;

cElectron transport layer solution:

[6,6]-Phenyl-C61-butyric acid methyl ester (PCBM) was dissolved in chlorobenzene at a concentration of 20 mg/mL. The solution was stirred at room temperature for 3 hours to obtain a PCBM solution.

d hole blocking layer solution:

Dissolve BCP in isopropyl alcohol at a concentration of 0.2 mg/mL and stir for 3 hours at room temperature to obtain a BCP solution.

Pretreatment of S02 substrate:

The ITO glass substrate was first ultrasonically cleaned in deionized water for 30 minutes, then in acetone for 30 minutes, and finally in isopropyl alcohol (IPA) for 30 minutes, then dried with a nitrogen gun and placed in a UV ozone processor Process in medium for 30 minutes and set aside.

Preparation of S03 hole transport layer:

The filtered hole transport layer solution was spin-coated on the ITO substrate at a spin-coating rate of 3000 rpm and a spin-coating time of 30 s, followed by annealing at 100°C for 10 min.

Preparation of S04 perovskite film layer:

Spin-coat the prepared perovskite film solution on the hole transport layer at a spin-coating rate of 4500 rpm and a spin-coating time of 40 seconds. At the 25th second of spin-coating, drop the antisolvent chlorobenzene 0.55 on the film layer. mL, and then annealed in the air at 150°C for 15 minutes, with the humidity controlled at 30-45%, and cooled before use.

Preparation of S05 electron transport layer:

Spin-coat the PCBM solution on the perovskite film layer at a rotation speed of 3000 rpm for 60 s.

Preparation of S06 hole blocking layer:

Spin-coat the BCP solution on the PCBM film layer at a rotation speed of 4000 rpm for 60 s.

Preparation of S07 electrode:

Use vacuum evaporation equipment to evaporate 120nm thick silver (Ag) as an electrode on the surface of BCP using thermal evaporation. The vacuum degree is controlled below 7*10 ^-4 Pa.

Comparative example 3

Compared with Example 3, the only difference is that the additive [4-(trifluoromethyl)phenyl]methylphosphonic acid is not added to the perovskite precursor.

The perovskite solar cells obtained in Example 3 and Comparative Example 3 were encapsulated, and the encapsulated cells were placed on a heating table at 85°C to test the cell efficiency, which was recorded every 72 hours. As shown in Figure 4, it can be seen that after 576 hours of heating Finally, the battery of Example 3 still retained the initial efficiency of 93.8%, while the efficiency of Comparative Example 3 only remained at 88.7%. It can be seen that the thermal stability of the battery with additives is much higher than that of the unmodified comparative example.

The basic principles and main features of the present invention and the advantages of the patent of the present invention have been shown and described above. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments only describe one or more embodiments of the present invention. Without departing from the spirit and scope of the present invention, the present invention Various changes and modifications are possible, which fall within the scope of the claimed invention. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims (7)

1. An inversion perovskite solar cell, includes perovskite rete, its characterized in that: the perovskite film layer material comprises a perovskite material and an additive, wherein the perovskite material is perovskite ABX ₃ Wherein A is an organic/inorganic cation, B is a metal ion, X is a halogen group; the additive is [4- (trifluoromethyl) phenyl ]]Methyl phosphonic acid;

the preparation method of the inversion perovskite solar cell comprises the following steps:

preparing a hole transport layer: the hole transport layer is arranged on the transparent conductive substrate;

preparing a perovskite film layer: mixing the component a, the component b and the component c, and depositing on the hole transport layer after mixing, wherein the deposition mode is one of spin coating and knife coating; the component a is one component or the combination of two components of lead iodide and lead bromide, the component b is one component or the combination of a plurality of components of cesium iodide, rubidium iodide, formamidine iodine, formamidine bromine, formamidine chlorine, methylamine iodine, methylamine bromine, methylamine chlorine, cesium chloride and cesium bromide, and the component c is [4- (trifluoromethyl) phenyl ] methylphosphonic acid;

preparing an electron transport layer: the electron transport layer is arranged on the perovskite film layer;

preparing an electrode layer;

the [ 4-trifluoromethyl ] phenyl group]Methylphosphonic acid and perovskite ABX ₃ The molar ratio of (2) is (0.01-1)%.

2. The inverted perovskite solar cell of claim 1, wherein: the preparation method of the perovskite film layer comprises the following steps:

a, mixing the component a, the component b and the component c, and depositing on the hole transport layer after mixing, wherein the deposition mode is one of spin coating and knife coating; the component a is one component or the combination of two components of lead iodide and lead bromide, the component b is one component or the combination of a plurality of components of cesium iodide, rubidium iodide, formamidine iodine, formamidine bromine, formamidine chlorine, methylamine iodine, methylamine bromine, methylamine chlorine, cesium chloride and cesium bromide, and the component c is [4- (trifluoromethyl) phenyl ] methylphosphonic acid;

b, auxiliary crystallization film forming: after the deposition is finished, the perovskite film layer is formed into a wet film, wherein the film forming mode is one or more of vacuum drying, anti-solvent dripping and air knife curing;

c, heating and annealing after forming a wet film, evaporating residual solvent and promoting the crystallization of the perovskite film layer; is prepared.

3. The inverted perovskite solar cell of claim 1, wherein: the B is Pb ²⁺ 。

4. The inverted perovskite solar cell of claim 1, wherein: the perovskite material and the additive are prepared into a mixed solution and then coated on the hole transport layer, the coating mode is spin coating, the spin coating speed is 4000-5000 rpm, the spin coating time is 30-55 s, and the chlorobenzene solution is dripped in the spin coating process.

5. The inverted perovskite solar cell of claim 1, wherein: the preparation method of the perovskite film layer comprises the following steps:

a, preparing a perovskite film layer solution: preparing mixed solution of lead iodide, formamidine iodine and methylamine chloride, and adding additive [4- (trifluoromethyl) phenyl ]]Methylphosphonic acid, additive relative to perovskite ABX ₃ The molar ratio of (2) is 0.01%;

b, spin-coating the prepared perovskite film layer solution on the hole transport layer, wherein the spin-coating speed is 4000rpm, the spin-coating time is 35s, 0.6mL of anti-solvent chlorobenzene is added dropwise in the spin-coating, then annealing is performed for 25min at 140 ℃, the humidity is controlled to be 30-40%, and the annealing is completed for standby.

6. The preparation method of the inverted perovskite solar cell is characterized by comprising the following steps of: comprises the following steps

Preparing a hole transport layer: the hole transport layer is arranged on the transparent conductive substrate;

preparing a perovskite film layer: the perovskite film layer is arranged on the hole transport layer, the perovskite film layer material comprises a perovskite material and an additive, and the perovskite material is used for forming a perovskite structure ABX ₃ Wherein A is an organic/inorganic cation, B is a metal ion, X is a halogen group, and the additive is [4- (trifluoromethyl) phenyl ]]Methyl phosphonic acid;

preparing an electron transport layer: the electron transport layer is arranged on the perovskite film layer;

preparing an electrode layer;

the additive material and perovskite ABX ₃ The molar ratio of the component a to the component b is (0.01-1)%, the component a is one component or the combination of two components of lead iodide and lead bromide, and the component b is one component or the combination of a plurality of components of cesium iodide, rubidium iodide, formamidine iodine, formamidine bromine, formamidine chlorine, methyl amine iodine, methyl amine bromine, methyl amine chlorine, cesium chloride and cesium bromide.

7. The method of fabricating an inverted perovskite solar cell according to claim 6, wherein: a hole blocking layer is disposed between the electron transport layer and the electrode layer, the hole blocking layer satisfying one or a combination of both of:

the hole blocking layer material is 2, 9-dimethyl-4, 7-diphenyl-1, 10-phenanthroline;

the hole blocking layer is used for evaporating and plating a film on the electron transport layer by utilizing a thermal evaporation mode or forming a film layer by adopting a solution deposition mode;

the preparation step of the hole blocking layer is arranged between the preparation of the electron transport layer and the preparation of the electrode layer.