CN111668377B

CN111668377B - Perovskite solar cell with Mo-tin dioxide as electron transport layer and preparation method thereof

Info

Publication number: CN111668377B
Application number: CN202010510530.6A
Authority: CN
Inventors: 刘向阳; 赵晓伟; 牛晨; 丁恒川
Original assignee: Henan University
Current assignee: Henan University
Priority date: 2020-06-08
Filing date: 2020-06-08
Publication date: 2022-02-18
Anticipated expiration: 2040-06-08
Also published as: CN111668377A

Abstract

The present application discloses a perovskite solar cell with Mo-SnO ₂ as an electron transport layer and a preparation method thereof. The preparation process of the solar cell is as follows: (1) Deposition Mo-SnO ₂ on a clean ITO electrode for electron transport layer; (2) deposition of NH ₄ Cl/KCl interface modification layer on Mo-SnO ₂ electron transport layer; (3) introduction of P123 copolymer into (FAMA)CsPbIBr system; (4) on NH ₄ Cl/KCl interface The (FAMA) CsPbIBr photosensitive layer was deposited on the modified layer; (5) the Spiro‑OMeTAD hole transport layer was deposited on the photosensitive layer; (6) the Au counter electrode was evaporated on the Spiro‑OMeTAD hole transport layer. The average photoelectric conversion efficiency of the prepared solar cells has reached 22.83%, the highest photoelectric conversion efficiency has exceeded 22.97%, and it shows good light stability.

Description

Perovskite solar cell with Mo-tin dioxide as electron transport layer and preparation method thereof

Technical Field

The invention belongs to the technical field of solar cells, and particularly relates to a perovskite solar cell with Mo-tin dioxide as an electron transport layer and a preparation method thereof.

Background

Solar cells are an important technical basis for converting solar energy into electric energy in a large scale, and the development of solar cells is a new green technology for relieving the contradiction between economic development and energy and environment, wherein the crystal silicon solar cells have remarkable progress in the aspects of conversion efficiency, preparation cost and the like and occupy most of application markets. Currently, solar cell research presents several new directions: 1. developing a top battery or a bottom battery matched with the crystalline silicon battery, and constructing a laminated battery with the theoretical efficiency of more than 33%; 2. the novel flexible, light and colorful battery is developed, the complementation with the crystalline silicon battery is realized, and the application requirements of different markets are met; 3. explore new photosensitive materials (simple, non-toxic, low-cost, high abundance and the like) and prepare the novel solar cell. For a new research hotspot in the photovoltaic field, the performance of the organic-inorganic hybrid perovskite solar cell is remarkably improved and exceeds the highest efficiency of a semiconductor compound solar cell (such as CdTe, CuInGaSn and the like). The perovskite material has the characteristics of simplicity, low price and solution processability, and the thin-film solar cell technology can replace the existing photovoltaic technology and realize low-cost development. In recent years, perovskite solar cells have breakthrough progress in the aspects of basic structure, working principle, component substitution, morphology optimization, crystallization improvement, interface passivation, electron/hole transport layers, all-inorganic perovskite, lead-free/lead-less perovskite, commercial exploration and the like, the photoelectric conversion efficiency of the perovskite solar cells is rapidly improved from 3.8% to 25.2%, and the researches lay a good experimental and theoretical foundation for deeply exploring the perovskite solar cells and promoting the commercialization of the perovskite solar cells.

However, the existing perovskite solar cell is based on mesoporous TiO₂And nano SnO₂Being an electron-transporting layer, TiO₂And SnO₂The conductivity is poor, the electron mobility is low, and the performance of the perovskite solar cell is seriously influenced. The novel electron transport layer material is prepared by a low-temperature solution method, the electron transport property of the film is improved, the efficient extraction of photoproduction charges is promoted, the performance of the perovskite solar cell is improved, the large-scale preparation of the perovskite solar cell is realized, and the rapid commercialization of the perovskite solar cell is promoted.

Disclosure of Invention

The invention aims to provide a perovskite solar cell taking Mo-tin dioxide as an electron transport layer and a preparation method thereof. The method can improve the electron transmission characteristic of the electron transmission layer and the photoelectric conversion efficiency of the perovskite solar cell, can explore the large-scale preparation of the perovskite solar cell, and provides experimental conditions and key technologies for the rapid commercial exploration of the perovskite solar cell.

Based on the purpose, the invention adopts the following technical scheme:

Mo-SnO₂Preparation method of perovskite solar cell as electron transport layerThe method comprises the following steps (the electron transport layer is finished in an air environment, and the other preparation processes are finished in a glove box):

(1) deposition of Mo-SnO on clean ITO electrodes₂The electron transport layer comprises the following specific processes: Mo-SnO₂Diluting the water dispersion solution with deionized water, adding ammonia water to adjust the pH value to 9-10, and carrying out spin coating on the Mo-SnO with the pH value adjusted₂Depositing the aqueous dispersion solution on a clean ITO electrode, and annealing at 120 ℃ for 30min to obtain Mo-SnO₂An electron transport layer;

(2) in Mo-SnO₂Deposition of NH on the electron transport layer₄Cl/KCl is used as an interface modification layer;

(3) at NH₄Deposition of P123-containing (FA) on Cl/KCl interface modification layer_0.85MA_0.15)_1-xCs_xPb(I_1-yBr_y)₃The value range of x is 0.01-0.1, and the value range of y is 0.1-0.5;

(4) depositing a Spiro-OMeTAD hole transport layer on the photosensitive layer;

(5) and (4) evaporating an Au counter electrode on the Spiro-OMeTAD hole transport layer to obtain the composite material.

The Mo-SnO₂The aqueous dispersion solution was obtained by the following method:

(a) mixing Sn powder and MoO₃Mixing the powders, putting the mixture into the bottom of a round-bottom flask, and adding deionized water; stirring in an ice water bath, wherein the molar weight of Mo accounts for 1-8% of that of Sn;

(b) dropwise adding acetic acid into the product obtained in the step (a), and stirring the mixture at the temperature of below 50 ℃ until Sn powder and MoO₃Completely dissolving;

(c) adding H dropwise to the solution of step (b)₂O₂；

(d) Dropwise adding the solution obtained in the step (c) into an ammonia water solution, and stirring to obtain a precipitate; aging the precipitate for 12-24 h under the stirring state, repeatedly carrying out suction filtration and washing until the conductivity of the filtrate is less than or equal to 250 mu S cm^-1To obtain Mo-SnO₂Precursor solution;

(e) the obtained Mo-SnO₂Diluting the precursor solution with deionized waterReleasing, adjusting the pH value to 9-10 by using ammonia water, and carrying out hydrothermal reaction at 120-230 ℃ for 12-24 h to obtain Mo-SnO₂An aqueous dispersion solution.

Preferably, when the amount of Sn powder is 10 g, 55-65 mL of acetic acid with the concentration of 15-20 wt% is added in the step (b), and 3-5 mL of H with the concentration of 10-20 wt% is added in the step (c)₂O₂And (d) adding 55-65 mL of 10-15 wt% ammonia water.

The preparation process of the clean ITO electrode is as follows: selecting a glass sheet with deposited ITO strip electrodes, and repeatedly wiping and washing the glass sheet by using a detergent to remove oil stains on the surface of the glass sheet; dividing the ITO conductive glass into regular small pieces, such as 1 cm multiplied by 1 cm, and sequentially carrying out ultrasonic treatment in deionized water for 30min, acetone solution for 30min and isopropanol solution for 30 min; and drying the obtained ITO glass sheet in an oven at 100 ℃ for 30min to obtain a clean ITO electrode.

Further, the NH₄The preparation process of the Cl/KCl interface modification layer is as follows: reacting NH₄Adding Cl and KCl into deionized water according to the molar ratio of 1:1, stirring to fully dissolve the Cl and the KCl to obtain NH₄The total concentration of Cl and KCl is 0.5 mg mL^-1Mixing the solution, and depositing 60 mu L NH at one time₄Cl/KCl solution to Mo-SnO₂And annealing the electron transport layer to obtain the final product.

Further, said (FA)_0.85MA_0.15)_1-xCs_xPb(I_1-yBr_y)₃The photosensitive layer was prepared as follows: 0.85X (1-x) mmol of FAI, 0.15X (1-x) mmol of MAI, and (3(1-y) -1)/2 mmol of PbI were sequentially weighed₂、3y/2 mmol PbBr₂X mmol CsI and 9.12 mg Pb (SCN)₂Mixing, adding a mixed solvent of DMSO and DMF in a volume ratio of 1:4, placing on a hot table at 60 ℃ in a glove box for 12 hours until the solid is completely dissolved, adding a triblock copolymer P123, wherein the concentration of the triblock copolymer P123 in the solution is 2.5 mg/mL-10.0 mg/mL, and stirring at room temperature for 1-2 hours in a sealing manner to obtain (FA)_0.85MA_0.15)_1-xCs_xPb(I_1-yBr_y)₃A precursor; will obtain (FA)_0.85MA_0.15)_1-xCs_xPb(I_1-yBr_y)₃Deposition of precursor to NH₄Annealing the Cl/KCl interface modification layer to obtain (FA)_0.85MA_0.15)_1-xCs_xPb(I_1-yBr_y)₃A photosensitive layer.

(FA_0.85MA_0.15)_1-xCs_xPb(I_1-yBr_y)₃The photosensitive layer is specifically (FA)_0.85MA_0.15)_0.95Cs_0.05PbI_2.7Br_0.3The preparation method comprises the following specific steps: 0.8075 mmol of FAI, 0.1425 mmol of MAI and 0.85 mmol of PbI are weighed in sequence₂、0.15 mmol PbBr₂0.05 mmol CsI and 9.12 mg Pb (SCN)₂Mixing, adding 600 muL DMF and 150 muL DMSO, and placing the solution on a 60 ℃ hot table in a glove box for 12 h until the solid is completely dissolved; 72 muL (FA)_0.85MA_0.15)_0.95Cs_0.05PbI_2.7Br_0.3Deposition of precursor solution to NH₄And (3) on the Cl/KCl interface modification layer, keeping the first step at 1000 rpm for 10 s during spin coating, keeping the second step at 5000 rpm for 30 s, depositing 200 mu L chlorobenzene by spin coating by using an anti-solvent method 10 s before the second step is finished, and annealing at 100 ℃ for 30min to obtain (FA/KCl interface modification layer)_0.85MA_0.15)_0.95Cs_0.05PbI_2.7Br_0.3A photosensitive layer.

Further, the specific preparation process of the Spiro-OMeTAD hole transport layer is as follows: adding 72.3 mg of Spiro-OMeTAD into a mixed solution consisting of 1 mL of chlorobenzene, 28.5 mul of 4-tert-butylpyridine, 18.5 mul of Li-TFSI and 18.5 mul of Co (III) -TFSI, stirring until the mixture is completely dissolved to obtain a Spiro-OMeTAD solution, and performing spin coating to deposit the Spiro-OMeTAD solution to obtain a hole transport layer.

Further, Mo-SnO obtained by the preparation method₂The perovskite solar cell of the electron transmission layer comprises an ITO substrate, and Mo-SnO is sequentially arranged on the ITO substrate from bottom to top₂Electron transport layer, NH₄Cl/KCl interface modification layer and (FA)_0.85MA_0.15)_0.95Cs_0.05PbI_2.7Br_0.3A photosensitive layer, a Spiro-OMeTAD hole transport layer, and an Au counter electrode layer, wherein M iso-SnO₂Thickness of electron transport layer is 25 nm, NH₄The thickness of the Cl/KCl interface modification layer is 3-5 nm, (FA)_0.85MA_0.15)_0.95Cs_0.05PbI_2.7Br_0.3The thickness of the photosensitive layer is 580 nm, the thickness of the Spiro-OMeTAD hole transport layer is 120 nm, and the thickness of the Au counter electrode layer is 80 nm.

For glass flake/Mo-SnO₂/(FA_0.85MA_0.15)_0.95Cs_0.05PbI_2.7Br_0.3The substrate of the/Au perovskite composite film is clean common glass.

The invention adopts non-chloride as raw material to prepare Mo-SnO₂And spin-coating and depositing the precursor and the corresponding nano particles to obtain the electron transport layer. SnO prepared by traditional method₂Electron transport layer, SnO needs to lose part of oxygen under high temperature or low pressure environment₂The conductive material has certain conductivity, and the corresponding carrier concentration and the electron mobility are lower and the conductivity is poorer; the invention dopes proper amount of Mo into SnO₂In the nano-particles, the carrier concentration and the electron transmission characteristic are improved, and SnO is improved₂Crystallinity, can be coated to deposit small-area electron transmission layer, and can also be used for preparing large-area Mo-SnO by blade coating, spraying and rolling method₂An electron transport layer; deposition of NH₄Cl/KCl passivates the interface defects of the electron transport layer and the perovskite layer, and promotes efficient separation and extraction of photo-generated charges; introducing the P123 copolymer into a perovskite precursor, passivating crystal grain boundaries and interface defects, and promoting efficient extraction of photo-generated charges; and a Spiro-OMeTAD hole transport layer is deposited, so that the photovoltaic response and the device performance of the perovskite solar cell are improved.

Compared with the prior art, the invention has the following advantages:

Mo-SnO prepared by the application₂/(FA_0.85MA_0.15)_0.95Cs_0.05PbI_2.7Br_0.3The perovskite solar cell has the advantages of simple preparation method, abundant raw material storage, wide application range, safety and environmental protection, and is based on a full low-temperature solution process, can be prepared in a large scale; the average photoelectric conversion efficiency of the prepared solar cell reaches 22.83 percent, and the highest photoelectric conversion efficiency is achieved by optimizing the device preparation processThe conversion efficiency is over 22.97%; under the condition of no packaging, the prepared optimized device is continuously illuminated for 50 hours, and the photoelectric conversion efficiency of the optimized device is still kept above 80 percent of the initial efficiency. The preparation method can realize the preparation of the perovskite solar cell based on the full low-temperature solution process, not only can obtain higher photoelectric conversion efficiency, but also can realize batch production and large-scale preparation by adopting blade coating, spraying and roll-to-roll rolling shaft preparation processes, reduces the production cost, has wide application prospect, and lays a good experimental foundation for promoting the commercialization of the perovskite solar cell.

Drawings

In fig. 1: (a) Mo-SnO prepared for example 1₂Surface topography; (b) Mo-SnO prepared for example 1₂/(FA_0.85MA_0.15)_0.95Cs_0.05PbI_2.7Br_0.3A sectional structure morphology graph of the solar cell;

in fig. 2: (a) glass sheet/Mo-SnO prepared for example 1₂/(FA_0.85MA_0.15)_0.95Cs_0.05PbI_2.7Br_0.3J-V curve of Au composite film in dark state; (b) Mo-SnO prepared for example 1₂/(FA_0.85MA_0.15)_0.95Cs_0.05PbI_2.7Br_0.3Perovskite solar cell impedance spectroscopy;

in fig. 3: (a) Mo-SnO prepared for example 1₂/(FA_0.85MA_0.15)_0.95Cs_0.05PbI_2.7Br_0.3A perovskite solar cell J-V curve; (b) Mo-SnO prepared for example 1₂/(FA_0.85MA_0.15)_0.95Cs_0.05PbI_2.7Br_0.3Perovskite solar cell external quantum efficiency spectroscopy (EQE);

in fig. 4: (a) is Mo-SnO₂/(FA_0.85MA_0.15)_0.95Cs_0.05PbI_2.7Br_0.3The photoelectric conversion efficiency of the perovskite solar cell changes along with the Mo doping mole percentage; (b) is Mo-SnO₂/(FA_0.85MA_0.15)_0.95Cs_0.05PbI_2.7Br_0.3The perovskite solar cell time-resolved surface photovoltaic response;

FIG. 5 is a curve showing the change of the photoelectric conversion efficiency of the perovskite solar cell with the addition concentration of the copolymer P123.

Detailed Description

The technical solutions of the present invention are described below with specific examples, but the scope of the present invention is not limited thereto.

Sn powder and MoO in the following examples₃The powder was obtained from Fisher Scientific Chemicals, Inc., the concentrated acetic acid, hydrogen peroxide and aqueous ammonia were obtained from Amazon Chemicals, Inc., MAI (methylamine hydroiodide), FAI (formamidine hydroiodide), PbI₂、PbBr₂、CsI、DMSO、DMF、Pb(SCN)₂Chlorobenzene, P123, NH₄Cl, KCl, Spiro-OMeTAD, 4-tert-butylpyridine, acetonitrile, Co (III) -TFSI, and Li-TFSI were purchased from Sigma Aldrich scientific Co.

Example 1

Mo-SnO₂The preparation method of the perovskite solar cell as the electron transport layer comprises the following steps:

(1) selecting a deposited ITO strip electrode and a common glass sheet, and repeatedly wiping and washing the deposited ITO strip electrode and the common glass sheet by using a detergent to remove oil stains on the surface of the glass sheet; dividing the two into regular small pieces, such as 1 cm × 1 cm, and sequentially performing ultrasonic treatment in deionized water for 30min, acetone solution for 30min, and isopropanol solution for 30 min; and drying the obtained ITO electrode and the common glass sheet in an oven at 100 ℃ for 30min to obtain a clean ITO electrode and a common glass sheet.

(2) Preparation of Mo-SnO₂Electron transport layer: 10 g of Sn powder and 0.485 g of MoO are weighed in sequence₃Powder (Mo in 4 mol% relative to Sn) was added to a two-necked round bottom flask, 30 mL of deionized water was added, and stirring was continued (due to the presence of Sn powder and MoO)₃The powder dissolution can generate more heat, and the whole experiment process is carried out in an ice-water bath in order to avoid the solution overflowing the flask); weighing 30 mL of concentrated acetic acid (36-38 wt%) and diluting with deionized water according to the volume ratio of 1:1, slowly dripping the diluted acetic acid into the aqueous solution at the temperature of lower than 50 DEG CStirring the mixture continuously to ensure that the Sn powder and the MoO are mixed₃Completely dissolving to form a transparent solution; 2 mL of H was measured₂O₂(30 wt%) diluted with deionized water according to the volume ratio of 1:1, and slowly added into the transparent solution dropwise without stirring to ensure that Mo is ensured⁶⁺Is not reduced to Mo⁴⁺(ii) a Slowly dripping 60 mL of ammonia water (the ammonia water with the concentration of 28 wt% and deionized water are diluted according to the volume ratio of 1: 1) into the solution, and continuously stirring to ensure that the atomic-level uniform coprecipitation is formed; aging the precipitate overnight under the condition of continuous stirring, repeatedly performing suction filtration and washing by using deionized water until the conductance is less than or equal to 250 mu S cm^-1Thus obtaining Mo-SnO₂And (3) precursor solution. FIG. 1 (a) shows Mo-SnO₂Scanning electron microscope pictures after hydrothermal reaction crystallization show that Mo-SnO₂The particles are dispersed very uniformly and have an average particle diameter<10 nm。

100 mL of Mo-SnO was weighed₂Diluting the precursor solution with 30 mL of deionized water, and carrying out hydrothermal reaction at 230 ℃ for 18 h to obtain Mo-SnO with good crystallization₂Adjusting the pH value of the aqueous dispersion solution to 9-10 by using ammonia water (the concentration is 28 wt%), and depositing 60 mu L of Mo-SnO by using a spin coating method₂Dispersing the solution in water, and annealing at 120 deg.C for 30min on a hot bench to obtain Mo-SnO with a thickness of 25 nm₂An electron transport layer.

(3) Deposition of NH₄Cl/KCl interface modification layer: adding 5.35 mg of NH₄Dissolving Cl and 7.45 mg KCl into 25.6 mL deionized water, stirring for 10 min to fully dissolve the Cl and the KCl to obtain NH₄The total concentration of Cl/KCl is 0.5 mg mL^-1Mixing the solution in Mo-SnO₂Depositing 60 mu L NH by one-time spin coating₄Annealing the Cl/KCl solution for 10 min at 100 ℃ to obtain NH with the thickness of 2-4 nm₄And a Cl/KCl interface modification layer.

(4) Deposition (FA)_0.85MA_0.15)_0.95Cs_0.05PbI_2.7Br_0.3Photosensitive layer: 0.8075 mmol of FAI, 0.1425 mmol of MAI and 0.85 mmol of PbI are weighed in sequence₂、0.15 mmol PbBr₂0.05 mmol CsI and 9.12 mg Pb (SCN)₂Mixing, adding 600 muL DMF and 150 muL DMSO, and placing the solution on a 60 ℃ hot table in a glove box for 12 h until the solid is completely dissolved;adding the P123 copolymer solution according to the volume of P123 (molecular weight: 5750) in the perovskite precursor solution with the concentration of 5.0 mg/mL, sealing and stirring for 1-2 h in a glove box at room temperature, and dispersing and uniformly mixing; obtained from 72 μ L (FA)_0.85MA_0.15)_0.95Cs_0.05PbI_2.7Br_0.3Deposition of precursor solution to NH₄Keeping the first step at 1000 rpm for 10 s and the second step at 5000 rpm for 30 s on the Cl/KCl interface modification layer, carrying out spin-coating deposition on 200 mu L chlorobenzene by using an anti-solvent method 10 s before the second step is finished, and carrying out annealing treatment to obtain the chlorobenzene layer (FA/KCl interface modification layer) with the thickness of 580 nm_0.85MA_0.15)_0.95Cs_0.05PbI_2.7Br_0.3A photosensitive layer.

For a common glass substrate, depositing a perovskite layer and evaporating an Au electrode to obtain a glass sheet/Mo-SnO based on the same method₂/(FA_0.85MA_0.15)_0.95Cs_0.05PbI_2.7Br_0.3Fig. 2 (a) shows a J-V curve of the composite film in a dark state, which indicates that the composite film has a very low dark-state current, and also indicates that after introducing P123 and depositing KCl for modification, the grain boundary and interface defects can be passivated, and the dark-state current caused by the defect state is reduced;

(5) preparing a Spiro-OMeTAD hole transport layer: measuring 1 mL of chlorobenzene, 28.5 muL 4-tert-butylpyridine (TBP), 18.5 muL lithium bistrifluoromethanesulfonylimide (Li-TFSI) and 18.5 muL cobalt bistrifluoromethanesulfonylimide (Co (III) -TFSI), mixing, adding 72.3 mg of Spiro-OMeTAD into the solution, continuously stirring for 3-4 h to completely dissolve the solution, depositing 50 muL of Spiro-OMeTAD solution by spin coating, and naturally airing to obtain a 120 nm thick Spiro-OMeTAD hole transport layer.

(6) Vacuum evaporating Au counter electrode (thickness is 80 nm) to obtain Mo-SnO₂/(FA_0.85MA_0.15)_0.95Cs_0.05PbI_2.7Br_0.3Perovskite solar cell. FIG. 1 (b) is a cross-sectional morphology of the perovskite battery, which shows that the distribution of each component is clear, and the perovskite crystal particles are 800 nm-1500 nm, which shows that the perovskite crystal is good, the crystal grain size is large, and the perovskite battery has good morphology. FIG. 2 (b)The perovskite cell electrochemical impedance spectrum shows that the solar cell has very large interface charge recombination impedance in a low-frequency region, and after crystal grain boundary and interface modification is carried out by adopting P123 and KCl, the interface defect state concentration can be obviously reduced, and the interface charge recombination impedance is obviously improved. It is composed ofJ-VThe curve and the External Quantum Efficiency (EQE) are shown in FIGS. 3(a) and 3(b), and it can be seen from FIG. 3(a) that the open-circuit voltage of the cell is: (V _oc= 1.162V), short-circuit current: (J _sc=24.26 mAcm^-2) Fill factor (FF =0.81), photoelectric conversion efficiency (PCE =22.83%), indicating its superior photoelectric properties; as can be seen from fig. 3(b), the quantum efficiency (EQE) outside the visible light region of 420 to 790 nm is greater than 85.5%, which indicates that the perovskite solar cell has high photoelectric conversion efficiency in the entire visible light region.

Example 2

For Mo-SnO₂The Mo mol percentage content (Mo is 0, 2, 4, 6 and 8 mol percent relative to Sn) of the aqueous dispersion is gradually increased, and tests show that Mo-SnO with different Mo doping mol percentages₂The specific results of the electronic conductivity are shown in table 1, and table 1 shows that the electronic conductivity of the doped Mo can be obviously improved.

TABLE 1 Mo-SnO after introduction of different Mo mol percents₂Electrical conductivity of electrons

Mo-SnO with different Mo doping amounts₂Preparation of Mo-SnO with different doping amounts by using aqueous dispersion₂The electron transmission layer (mol percent of Mo relative to Sn is 0, 2, 4, 6, 8 mol%) and the corresponding perovskite solar cell photoelectric conversion efficiency shows a trend of increasing first and then decreasing, other is the same as example 1; perovskite solar cell photoelectric conversion efficiency along with Mo-SnO₂The Mo/Sn mol% variation curve in the electron transport layer is shown in FIG. 4 (a); the method shows that Mo-SnO can be obviously improved by introducing a proper amount (2-4 mol%) of Mo under the premise of not obviously improving the carrier concentration₂Electron transport property, photoelectric conversion efficiency increased from 18.85% to 22.83% of maximum efficiency (in terms of Sn molar ratio)The addition amount of Mo is 4.0 mol percent, so that photo-generated charge extraction is promoted, and the performance of a photovoltaic device is improved; when the addition amount of Mo is 4.0 mol%, the battery detection parameters are as follows: open circuit voltage (V _oc= 1.162V), short-circuit current: (J _sc=24.26 mAcm^-2) Fill factor (FF =0.81), photoelectric conversion efficiency (PCE = 22.83%); FIG. 4(b) is a Mo-SnO time resolved surface photovoltaic response of a solar cell₂/FA_0.8Cs_0.2Pb(I_0.7Br_0.3)₃The solar cell has stronger transient surface photovoltaic response, and shows that after P123 and KCl deposition are introduced, crystal grain boundary and interface defects can be passivated, and efficient separation and extraction of photo-generated charges are promoted.

Example 3

For the introduced P123 copolymer, the concentration of the copolymer in the perovskite precursor solution is gradually increased (2.5 mg/mL, 5.0 mg/mL, 7.5 mg/mL, 10.0 mg/mL), and the photoelectric conversion efficiency of the corresponding perovskite solar cell also shows a trend of increasing and then decreasing, and the rest is the same as that of example 1. The curve of the photoelectric conversion efficiency of the perovskite solar cell along with the introduction of the P123 copolymer concentration is shown in FIG. 5, as can be seen from FIG. 5, the photoelectric conversion efficiency shows a trend of first-increasing and then-decreasing changes, the improvement of the concentration of the copolymer P123 can better passivate perovskite crystal grain boundary defects, but when the concentration of the copolymer P123 is too high, a passivation layer formed at the perovskite crystal grain boundary is thicker, and due to the insulating property of the copolymer P123, the separation and transmission of photo-generated charges are hindered, and the performance of a device is seriously influenced; the copolymer has the best photoelectric property when the concentration of the copolymer in the perovskite precursor solution is 5.0 mg/mL, the copolymer with the concentration can passivate perovskite defects, the quality and the electrical property of a perovskite thin film can be kept, and the photovoltaic response characteristic of a device is improved.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. with Mo-SnO ₂ as the preparation method of the perovskite solar cell of electron transport layer, is characterized in that, comprises the steps:

(1) The Mo-SnO ₂ electron transport layer was deposited on the clean ITO electrode. The specific process was as follows: the Mo-SnO ₂ aqueous dispersion solution was diluted with deionized water, and the pH value was adjusted to 9-10 with ammonia water. The Mo-SnO ₂ aqueous dispersion solution after adjusting the pH is deposited on the clean ITO electrode and annealed to obtain the Mo-SnO ₂ electron transport layer;

(2) Deposition of NH ₄ Cl/KCl on the Mo-SnO ₂ electron transport layer as an interface modification layer;

(3) A (FA _0.85 MA _0.15 ) _1-x Cs _x Pb(I _1-y Br _y ) ₃ photosensitive layer containing P123 was deposited on the NH ₄ Cl/KCl interface modification layer, and the value of x ranged from 0.01 to 0.1 , the value range of y is 0.1~0.5;

(4) depositing a Spiro-OMeTAD hole transport layer on the photoactive layer;

(5) Evaporate the Au counter electrode on the Spiro-OMeTAD hole transport layer to obtain;

The Mo-SnO ₂ aqueous dispersion solution is obtained by the following method:

(a) Mix Sn powder and MoO ₃ powder, add deionized water; stir under ice-water bath, wherein Mo molar amount accounts for 1~8% of Sn molar amount;

(b) adding acetic acid dropwise to the obtained product in step (a), and stirring at lower than 50 °C until the Sn powder and MoO ₃ are completely dissolved;

(c) adding H ₂ O ₂ dropwise to the solution of step (b);

(d) Add ammonia water dropwise to the solution obtained in step (c), stir to obtain a precipitate; age the precipitate under stirring for 12-24 hours, and repeatedly wash with suction filtration until the conductivity of the filtrate is ≤ 250 µS cm ^-1 , to obtain Mo- SnO ₂ precursor solution;

(e) The obtained Mo-SnO ₂ precursor solution was diluted with deionized water, adjusted to pH 9~10 with ammonia water, and hydrothermally reacted at 120~230 °C for 12~24 h to obtain the Mo-SnO ₂ water dispersion. solution.

2. The method for preparing a perovskite solar cell using Mo- _SnO as an electron transport layer according to claim 1, wherein when the Sn powder is 10 g, the concentration of 55-65 mL added in step (b) is 15~20wt% acetic acid, in step (c), add 3~5 mL with a concentration of 10~20 wt% H ₂ O ₂ , and in step (d) with 55~65 mL with a concentration of 10~15 wt% ammonia water.

3. The preparation method of the perovskite solar cell with Mo-SnO ₂ as the electron transport layer according to claim 1, wherein the preparation process of the NH ₄ Cl/KCl interface modification layer is as follows: NH ₄ Cl and KCl was added to deionized water at a molar ratio of 1:1, and the two were fully dissolved by stirring to obtain a mixed solution with a total concentration of 0.5 mg mL ^-1 of NH ₄ Cl and KCl _. SnO ₂ electron transport layer, annealing treatment, namely.

4. the preparation method of the perovskite solar cell with Mo-SnO ₂ as electron transport layer according to claim 1, is characterized in that, the described (FA _0.85 MA _0.15 ) _1-x Cs _× Pb (I The preparation process of the _1-y Br _y ) ₃ photosensitive layer is as follows: Weigh 0.85×(1-x) mmol FAI, 0.15×(1-x) mmol MAI, and (3(1-y)-1)/2 mmol in turn. PbI ₂ , 3y/2mmol PbBr ₂ , x mmol CsI and 9.12 mg Pb(SCN) ₂ were mixed, and a mixed solvent of DMSO and DMF with a volume ratio of 1:4 was added, and placed at 60 °C until the solid was completely dissolved to obtain perovskite Precursor solution, add triblock copolymer P123, the concentration of triblock copolymer P123 in the perovskite precursor solution is 2.5 mg/mL~10.0 mg/mL, sealed and stirred at room temperature for 1~2 h, you can get ( FA _0.85 MA _0.15 ) _1-x Cs _x Pb(I _1-y Br _y ) ₃ precursor solution; the obtained (FA _0.85 MA _0.15 ) _1-x Cs _x Pb(I _1- _y Br _y ) ₃ precursor solution It was deposited on the NH ₄ Cl/KCl interface modification layer and annealed to obtain a (FA _0.85 MA _0.15 ) _1-x Cs _x Pb(I _1- _y B _y ) ₃ photoactive layer.

5. the preparation method of the perovskite solar cell with Mo-SnO ₂ as electron transport layer according to claim 4, is characterized in that, (FA _0.85 MA _0.15 ) _1-x Cs _x Pb (I _1-y Br _y ) _3. The photosensitive layer is specifically (FA _0.85 MA _0.15 ) _0.95 Cs _0.05 PbI _2.7 Br _0.3 , and the specific preparation process is as follows: 0.8075 mmol FAI, 0.1425 mmol MAI, 0.85 mmol PbI _{2 , 0.15 mmol PbBr 2} _, 0.05 mmol CsI and 9.12 mg Pb(SCN) ₂ , mixed, added 600 µL DMF and 150 µL DMSO, and the solution was placed on a hot stage at 60 °C in a glove box for 12 h until the solid was completely dissolved; triblock copolymer P123 was added, triblock The concentration of the segmented copolymer P123 in the perovskite precursor solution is 2.5 mg/mL~10.0 mg/mL, and it is sealed and stirred at room temperature for 1~2 h to obtain (FA _0.85 MA _0.15 ) _1-x Cs _x Pb(I _{1- y} Br _y ) ₃ precursor solution; 72 µL (FA _0.85 MA _0.15 ) _0.95 Cs _0.05 PbI _2.7 Br _0.3 precursor solution was deposited on the NH ₄ Cl/KCl interface modification layer. During spin coating, the first step was kept at 1000 rpm 10 s, the second step was held at 5000 rpm for 30 s, and 10 s before the end of the second step, 200 µL of chlorobenzene was deposited by spin coating, and annealed to obtain a (FA _0.85 MA _0.15 ) _0.95 Cs _0.05 PbI _2.7 Br _0.3 photosensitive layer.

6 . The method for preparing a perovskite solar cell using Mo-SnO ₂ as an electron transport layer according to claim 1 , wherein the annealing in the step (1) refers to annealing at 120° C. for 30 min. 7 .

7 . The method for preparing a perovskite solar cell using Mo-SnO ₂ as an electron transport layer according to claim 5 , wherein the annealing during the preparation of the photoactive layer refers to annealing at 100° C. for 30 min. 8 .

8. The perovskite solar cell with Mo- _SnO as the electron transport layer obtained by the method of any one of claims 1 to 7, characterized in that it comprises an ITO substrate, and there are sequentially from bottom to top on the substrate layer Mo-SnO ₂ electron transport layer, NH ₄ Cl/KCl interface modification layer, (FA _0.85 MA _0.15 ) _1-x Cs _x Pb(I _1-y Br _y ) ₃ photoactive layer, Spiro-OMeTAD hole transport layer, Au Counter electrode layer, wherein the thickness of Mo-SnO ₂ electron transport layer is 25 nm, the thickness of NH ₄ Cl/KCl interface modification layer is 2~4 nm, (FA _0.85 MA _0.15 ) _1-x Cs _x Pb(I _1-y Br _y ) ₃ The thickness of the photoactive layer is 580 nm, the thickness of the Spiro-OMeTAD hole transport layer is 120 nm, and the thickness of the Au counter electrode layer is 80 nm.