A method for preparing a high-efficiency anti-perovskite battery based on buried bottom interface stress release and a battery device

Abstract

The application relates to the technical field of solar cells, in particular to a method for preparing an efficient transverse perovskite cell based on buried interface stress release and a cell device. x The cell device structure is sequentially arranged from bottom to top as an FTO substrate, a NiO 2+ The hole transport layer, the SAM hole transport layer, the interface buffer layer, the perovskite absorption layer, the PCBM electron transport layer, the BCP blocking layer and the silver electrode are sequentially arranged from bottom to top. In the application, the interface buffer agent is integrated at the buried interface of the perovskite layer, and due to the symmetrical molecular structure and unique active sites (C-N) of the interface buffer agent, the formation of iodine vacancy defects is significantly inhibited through different coordination with Pb 2+ , so that the extraction and transfer of holes are effectively promoted, and the buried interface stress in the inverted perovskite solar cell (PSC) is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solar cells, in particular to a method for preparing a high-efficiency transverse perovskite cell based on buried interface stress release and a cell device. BACKGROUND

[0002] Perovskite has many advantages such as high extinction coefficient, high carrier mobility, low exciton binding energy, and easy solution preparation. The certified efficiency of the current formal perovskite solar cell has reached 26.3%, and the certified efficiency of the transverse cell has also exceeded 26.7%.

[0003] In a perovskite cell device, the stability of the perovskite thin film often determines the stability of the entire device. At present, all perovskite thin films need to go through an annealing step. During this process, due to the mismatch of the thermal expansion coefficients between the perovskite and the substrate, adverse structural deformation and residual stress often occur at the buried interface between the perovskite and the substrate. This residual stress accelerates the degradation of the perovskite thin film and destroys the stability of the device, which is one of the important factors hindering the commercialization of perovskite solar cells.

[0004] Therefore, finding a perovskite buried interface stress release process with simple preparation process and low cost is currently one of the important topics for realizing the preparation of high-efficiency and stable perovskite solar cells. SUMMARY

[0005] In view of the problem of the device stability affected by residual stress in the perovskite cell in the prior art, the present application provides a method for preparing a high-efficiency transverse perovskite cell based on buried interface stress release and a cell device.

[0006] The present application is realized by the following technical solutions:

[0007] A method for preparing a high-efficiency transverse perovskite cell based on buried interface stress release,

[0008] Step 1, cleaning the FTO glass substrate to obtain a pretreated FTO glass substrate;

[0009] Step 2, spin coating a nickel oxide nanoparticle water dispersion solution on the surface of the pretreated FTO glass substrate, and then performing a first annealing treatment to obtain a primary product with a nickel oxide hole transport layer;

[0010] Step 3, dispersing SAM powder into an isopropanol solution to obtain a SAM isopropanol mixed solution, then spin coating the SAM isopropanol mixed solution onto the surface of the nickel oxide hole transport layer of the primary product, and then performing a second annealing treatment to obtain a secondary product with a SAM hole transport layer;

[0011] Step 4, spin-coat the triphenylamine derivative molecular solution to the surface of the SAM hole transport layer of the secondary product, and then perform a third annealing treatment to obtain a tertiary product with an interface buffer layer;

[0012] Step 5, spin-coat the perovskite precursor solution to the surface of the interface buffer layer of the tertiary product to obtain a quaternary product with a perovskite light absorption layer;

[0013] Step 6, spin-coat the PCBM chlorobenzene solution on the perovskite thin film of the quaternary product at room temperature to form a quinary product with a PCBM electron transport layer;

[0014] Step 7, prepare a BCP blocking layer on the PCBM electron transport layer of the quinary product to form a sexenary product with a BCP blocking layer;

[0015] Step 8, evaporate a silver electrode on the BCP blocking layer of the sexenary product to obtain a perovskite solar cell device.

[0016] Preferably, in step 1, the FTO glass substrate is fluorine-doped SnO2 transparent conductive glass; during cleaning, the FTO glass substrate is sequentially ultrasonically cleaned with acetone solution, isopropanol solution, ethanol solution, and ultrapure water, then dried, and finally subjected to ultraviolet ozone treatment to obtain a pretreated FTO glass substrate.

[0017] Preferably, in step 2, the nickel oxide nanoparticle / water in the nickel oxide nanoparticle aqueous dispersion is 0.5-1 mg / mL, the spin-coating speed is 3000r-5000r / 30s, and the spin-coating thickness is 10-40nm; during the first annealing treatment, the temperature is 100-150℃ and the time is 30-60min.

[0018] Preferably, in step 3, the concentration of the SAM isopropanol mixed solution is 0.5-1.5mg / mL, the spin-coating speed is 2000r-4000r / 30s; during the second annealing treatment, the temperature is 100-150℃ and the time is 5-25min.

[0019] Preferably, in step 4, the preparation of the triphenylamine derivative molecular solution is as follows: dissolve the triphenylamine derivative molecular powder in chlorobenzene solution to obtain a triphenylamine derivative molecular solution with a concentration of 0.5-1.5mg / mL; wherein the structure of the triphenylamine derivative molecule is as follows:

[0020]

[0021] During the third annealing treatment, the temperature is 100-150℃ and the time is 5-25min.

[0022] Preferably, in step 5, the preparation of the perovskite precursor solution is as follows: PbI2: CH(NH2)2I: CsI with a molar ratio of 1:0.98:0.02 is dissolved in a mixed solvent of DMSO: DMF = 1:4 to obtain the perovskite precursor solution;

[0023] When spin coating, the volume of the dropped perovskite solution is 9.6-11 muL / cm2 relative to the area of the perovskite film 2 ;

[0024] The thickness of the perovskite light absorption layer is 700-800 nm.

[0025] Preferably, in step 6, when spin coating, the volume of the dropped electron transport layer solution is 8-9.6 muL / cm2 relative to the area of the perovskite film 2 .

[0026] Preferably, in step 7, the solvent of the BCP solution is isopropanol, and when spin coating, the thickness of the BCP blocking layer is 3-8 nm; when vacuum thermal evaporation, the thickness of the BCP blocking layer is 5-15 nm.

[0027] Preferably, in step 8, a silver electrode with a thickness of 80-100 nm is deposited by thermal evaporation.

[0028] A perovskite solar cell device obtained by the method for preparing a high-efficiency inverted perovskite solar cell based on buried bottom interface stress release, characterized in that the structure from bottom to top is FTO substrate, NiO x hole transport layer, SAM hole transport layer, interface buffer layer, perovskite absorption layer, PCBM electron transport layer, BCP blocking layer and silver electrode.

[0029] Compared with the prior art, the present application has the following beneficial effects:

[0030] The method for preparing a high-efficiency inverted perovskite solar cell based on buried bottom interface stress release of the present application reduces the stress accumulation of the buried bottom interface in the inverted perovskite solar cell by introducing a triphenylamine derivative molecule (TAPC) with a multi-rigid structure at the interface between the hole transport layer and the perovskite, aiming to relieve the stress accumulation at the buried bottom interface and enhance the hole extraction capability, while optimizing the energy level arrangement.

[0031] The triphenylamine derivative buffer layer is introduced at the buried bottom interface of the perovskite layer, and specifically, the 4,4'-cyclohexylbis[N, N-bis(p-phenylphenylamine) aniline] (TAPC) molecule has multiple rigid structures, which effectively restricts the expansion and contraction of the crystal lattice, and reduces the stress accumulation at the interface. Secondly, it has a symmetrical molecular structure and a unique active site (C-N), which can effectively reduce the lattice mismatch between the perovskite and the FTO substrate, and can effectively reduce the stress accumulation at the interface. 2+The coordination of TAPC significantly inhibits the formation of iodine vacancy defects, thereby effectively promoting the extraction and transfer of holes. In addition, due to its enhanced compatibility, TAPC can well adjust the energy level arrangement between the hole transport layer and the perovskite. Based on these advantages, low-stress, high-quality perovskite films can be prepared, which are characterized by reduced charge transfer barriers, suppressed non-radiative recombination processes, and emphasize the importance of buried interface residual stress release for achieving efficient and stable inverted perovskite solar cells. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 Flow chart of the method for preparing efficient transverse perovskite battery based on buried interface stress release according to the present application;

[0033] Figure 2 Structural formula of the triphenylamine derivative molecule in the present application;

[0034] Figure 3 Infrared spectrum of TAPC prepared in Example 1 of the present application added with PbI2, and XPS test comparison chart after mixing perovskite and TAPC;

[0035] Figure 4 Comparison chart of (100) crystal plane diffraction peak shift of X-ray diffraction (XRD) on the upper surface and the lower surface of the perovskite thin film prepared in Example 1 of the present application and the perovskite thin film added with a buffer layer;

[0036] Figure 5 Comparison chart of SEM at the buried interface of the perovskite thin film prepared in Example 1 of the present application and the perovskite thin film added with a buffer layer;

[0037] Figure 6 Comparison chart of SEM on the upper surface of the perovskite thin film prepared in Example 1 of the present application and the perovskite thin film added with a buffer layer;

[0038] Figure 7 Comparison chart of steady-state fluorescence at the lower interface of the perovskite thin film prepared in Example 1 of the present application and the perovskite thin film added with a buffer layer;

[0039] Figure 8 Comparison chart of GIXRD on the upper surface of the perovskite thin film prepared in Example 1 of the present application and the perovskite thin film added with a buffer layer.

[0040] Figure 9 Comparison chart of photoelectric conversion efficiency of the perovskite thin film prepared in Example 1 of the present application and the perovskite thin film added with a buffer layer;

[0041] Figure 10 Comparison chart of photoelectric conversion efficiency of the perovskite thin film prepared in Example 2 of the present application and the perovskite thin film added with a buffer layer;

[0042] Figure 11 The perovskite thin film prepared in Example 3 of the present application is compared with the perovskite thin film with a buffer layer in terms of photoelectric conversion efficiency. DETAILED DESCRIPTION

[0043] The present application will be further described in conjunction with specific examples, which are intended to explain but not limit the present application.

[0044] The present application discloses a method for preparing high-efficiency transverse perovskite battery based on buried bottom interface stress release, referring to Figure 1 , comprising the following steps:

[0045] Step 1, cleaning the FTO glass substrate to obtain a pretreated FTO glass substrate; wherein the FTO glass substrate is fluorine-doped SnO2 transparent conductive glass; during cleaning, the FTO glass substrate is sequentially cleaned with acetone solution, isopropanol solution, ethanol solution and ultrapure water by ultrasonic cleaning, and each cleaning time is 30 min; then, the FTO glass substrate is dried at room temperature (25℃) by using a box-type oil-free reciprocating piston air compressor for 1-3 min; finally, the pretreated FTO glass substrate is obtained by ultraviolet ozone treatment.

[0046] Step 2, spin-coating a nickel oxide nanoparticle water dispersion solution on the surface of the pretreated FTO glass substrate, and then performing a first annealing treatment to obtain a primary product with a nickel oxide hole transport layer; wherein the concentration of nickel oxide nanoparticles in the nickel oxide nanoparticle water dispersion solution is 0.5-1 mg / mL, the spin-coating speed is 3000r-5000r / 30s, and the thickness of spin-coating is 10-40 nm; during the first annealing treatment, the temperature is 100-150 ℃, and the time is 30-60 min.

[0047] Step 3, dispersing SAM powder into isopropanol solution to prepare a SAM isopropanol mixed solution with a concentration of 0.5-1.5 mg / mL, and then spin-coating the SAM isopropanol mixed solution onto the surface of the nickel oxide hole transport layer of the primary product at a spin-coating speed of 2000r-4000r / 30s, and then performing a second annealing treatment to obtain a secondary product with a SAM hole transport layer; wherein, during the second annealing treatment, the temperature is 100-150 ℃, and the time is 5-25 min.

[0048] Step 4, spin-coating a triphenylamine derivative molecular solution onto the surface of the SAM hole transport layer of the secondary product, and then performing a third annealing treatment to obtain a tertiary product with an interface buffer layer; wherein the triphenylamine derivative molecular solution is prepared by dissolving triphenylamine derivative molecular powder in chlorobenzene solution to prepare a triphenylamine derivative molecular solution with a concentration of 0.5-1.5 mg / mL; wherein the structural formula of the triphenylamine derivative molecule is:

[0049]

[0050] The third annealing treatment is performed at a temperature of 100-150 DEG C for 5-25 min.

[0051] Step 5: spin coating a perovskite precursor solution to the surface of the interface buffer layer of the third product to obtain a fourth product with a perovskite light absorption layer; wherein the perovskite precursor solution is prepared by dissolving PbI2, CH(NH2)2I and CsI with a molar ratio of 1:0.98:0.02 in a mixed solvent of DMSO:DMF at a ratio of 1:4; during the spin coating, the volume of the perovskite solution added dropwise is 9.6-11 μL / cm 2 ; and the thickness of the perovskite light absorption layer is 700-800 nm.

[0052] Step 6: spin coating a PCBM chlorobenzene solution to the perovskite thin film of the fourth product at room temperature to form a fifth product with a PCBM electron transport layer; wherein during the spin coating, the volume of the electron transport layer solution added dropwise is 8-9.6 μL / cm 2 .

[0053] Step 7: preparing a BCP blocking layer on the PCBM electron transport layer of the fifth product by spin coating a BCP solution or vacuum thermal evaporation to form a sixth product with the BCP blocking layer; wherein the solvent of the BCP solution is isopropanol, and the thickness of the BCP blocking layer is 3-8 nm during the spin coating; and the thickness of the BCP blocking layer is 5-15 nm during the vacuum thermal evaporation.

[0054] Step 8: evaporating a silver electrode with a thickness of 80-100 nm on the BCP blocking layer of the sixth product by thermal evaporation to obtain a perovskite solar cell device.

[0055] The triphenylamine derivative molecule (model number CAS No. 58473-78-2, produced by Xi'an Bath Sunshine Energy Technology Co., Ltd., formerly Xi'an Baolai Optical Technology Co., Ltd.) is dissolved in chlorobenzene and the like organic solvents, shaken and uniformly dispersed for 5-8 h, and then spin coated on the prepared SAM hole transport layer and then annealed at high temperature, and the specific structure is FTO / NiOx / SAM / triphenylamine derivative molecule (structural formula as Figure 2The trisphenylamine derivative molecules have multiple rigid molecular groups containing benzene rings with C-N bonds, which can be well anchored to the buried interface of the perovskite, thereby limiting the lattice expansion and contraction of the perovskite film during annealing and cooling, thereby constructing a buried interface without residual stress accumulation, and promoting the ordered crystallization of the buried interface to improve the film growth quality and device stability. In addition, C-N can chelate unpaired Pb 2+ Capture it at the interface to limit the diffusion of Pb 2+ , thereby improving the long-term stability of the device.

[0056] The application also relates to a perovskite solar cell device prepared by the method for preparing a high-efficiency transverse perovskite solar cell based on stress release of a buried interface. x The structure of the perovskite solar cell device from bottom to top comprises an FTO substrate, a NiO

[0057] Embodiment 1

[0058] Step 1, cleaning the FTO glass substrate: select a fluorine-doped SnO2 (FTO) transparent conductive glass (2.5*2.5 cm 2 ), wipe the surface impurities with a dust-free paper, and then sequentially clean with acetone, isopropanol, ethanol and ultrapure water for 30 minutes, dry, and treat with ultraviolet ozone before use;

[0059] Step 2, preparation of a nickel oxide nanoparticle water dispersion:

[0060] First, prepare a nickel oxide nanoparticle water dispersion and ultrasonically disperse;

[0061] After spin coating and annealing of the nickel oxide nanoparticle water dispersion, a nickel oxide hole transport layer is obtained;

[0062] Step 3, preparation of a SAM solution:

[0063] First, prepare a SAM dispersion and ultrasonically disperse;

[0064] After spin coating and annealing of the SAM dispersion, a SAM hole transport layer is obtained;

[0065] Step 4, preparation of an interface buffer layer:

[0066] After the SAM substrate is annealed and cooled to room temperature, the buffer layer molecules are spin coated or evaporated on the SAM substrate, and then annealed.

[0067] Step 5, preparation of a perovskite light absorption layer;

[0068] PbI2:CH(NH2)2I:CsI were weighed and dissolved in DMSO / DMF mixed solvent; the mixed solution was sealed, stirred thoroughly, and filtered to obtain a clear perovskite solution for standby;

[0069] The perovskite precursor solution was uniformly coated on the surface of the interfacial buffer layer substrate; after spin-coating to obtain a perovskite wet film, the perovskite light absorption layer was obtained by placing the film on a 110°C hot stage for 20 min;

[0070] Step 6: Preparation of PCBM transport layer:

[0071] The annealed perovskite film was cooled to room temperature, and a PCBM solution was spin-coated on the perovskite substrate to obtain an electron transport layer.

[0072] Step 7, Preparation of BCP barrier layer.

[0073] The BCP solution was spin-coated on the surface of the PCBM layer or a 5 nm BCP layer was vacuum thermal evaporated on the surface of the PCBM layer.

[0074] Step 8, Silver electrode evaporation: the prepared film was transferred into an evaporation chamber, and a 80 nm thick silver electrode was evaporated using thermal evaporation method. The effective area of the cell under the mask plate was 0.09 cm 2 .

[0075] Referring to Figure 3 , PbI2 was added to the TAPC solution, and it was found by infrared spectroscopy that the C-N bond in the TAPC molecule was obviously shifted after the addition of PbI2. Then, the triphenylamine derivative molecule was spin-coated on the surface of the perovskite, and it was found by XPS test that the Pb 2+ in the perovskite was obviously shifted. The above results show that the C-N bond in the triphenylamine derivative molecule can anchor the under-coordinated Pb 2+ in the perovskite, thereby improving the long-term stability of the perovskite device.

[0076] Referring to Figure 4 , the introduction of an interfacial buffer layer (triphenylamine derivative molecule) between the hole transport layer and the perovskite releases the residual stress at the buried interface. We found that the (100) crystal face diffraction peak of the upper surface and the lower interface of the perovskite film without a buffer layer had a larger shift difference. This indicates that there is a large stress difference between the upper and lower surfaces of the annealed film, which may be caused by the mismatch of the thermal expansion coefficient between the substrate and the perovskite layer Figure 4 (a). The shift difference of the (100) crystal face diffraction peak of the upper and lower surfaces of the perovskite film grown on the buffer layer substrate is smaller, indicating that the residual stress in the film is released Figure 4 (b).

[0077] Referring to Figure 5 , in order to study the influence of introducing interface buffer on the quality of perovskite film, firstly, the buried interface of perovskite film was explored by using scanning electron microscope (SEM). The buried interface was shown by the lower interface peeling, and the results showed that the flatness of the film at the buried interface was poor, the grain growth was disordered, and there was obvious extrusion deformation at the grain boundary. This phenomenon may be due to the mismatch of the thermal expansion coefficient between the substrate and the perovskite during the annealing process, which eventually leads to stress accumulation at the buried interface ( Figure 5 a). On the contrary, after adding the buffer layer, the flatness of the film and the contact between the grain boundaries at the buried interface were improved because the buffer layer relieved the stress accumulation ( Figure 5 b).

[0078] Referring to Figure 6 , the scanning electron microscope of the upper surface of the perovskite showed that the upper surface film without buffer layer contained holes and had poor flatness, which may be due to the stress accumulation at the bottom interface, leading to disordered grain growth, thus exacerbating the stress accumulation at the upper surface film, leading to the extrusion of the upper surface grain ( Figure 6 a). In addition, the introduction of the buffer layer significantly reduced the extrusion deformation of the grain, indicating the stress relaxation of the upper surface film ( Figure 6 b).

[0079] Referring to Figure 7 , depth-resolved grazing incidence X-ray diffraction (GIXRD) technique was used. The GIXRD spectra corresponding to the (100) crystal plane at different ψ values are shown in Figure 7 , and Figure 7 a shows that the (100) plane distance increases with the increase of diffraction angle, according to the Bragg equation nλ = 2dsinθ, the blue shift of the scattering peak indicates that the crystal plane distance increases, indicating that there is lattice tensile strain in the perovskite film. The diffraction peak of the (100) crystal plane of the perovskite film after adding the buffer layer has only an almost invisible shift, indicating that the internal lattice tensile strain of the crystal plane is released ( Figure 7 b).

[0080] Referring to Figure 8 , the steady-state photoluminescence spectrum of the perovskite film at the buried interface is shown in Figure 8 a, in which the perovskite film grown on the interface buffer layer substrate has the strongest PL absorption peak, indicating that the treatment of the diphenylamine derivative molecule reduces the non-radiative recombination of the perovskite film. In addition, the average carrier lifetime of the films of the control group and the optimization group is 2553.8 ns and 3932.8 ns, respectively ( Figure 8b). These results show that the introduction of diphenylamine derivative molecules in the buried interface of perovskite can effectively improve the film quality and reduce non-radiative recombination. The enhancement of PL intensity and the extension of carrier lifetime both indicate the reduction of trap state density.

[0081] Battery device photoelectric conversion efficiency test: at room temperature, using a solar simulator of model 2400 of Keithley Company, under the condition of light intensity of 100 mW / cm 2 Battery efficiency test, by battery device photoelectric conversion efficiency test, the photoelectric conversion efficiency of the prepared perovskite solar cell is 25.72%. Referring to Figure 9 , the parameters of the device after adding the buffer layer are obviously improved, among which the filling of the device is obviously improved, which may be due to the release of residual stress at the interface, improving the film quality at the buried interface and promoting the ordered crystallization of the lower interface, and finally obtaining a PCE of 25.72.

[0082] Example 2

[0083] Step 1, cleaning FTO glass substrate: select fluorine-doped SnO2 (FTO) transparent conductive glass (2.5*2.5 cm 2 ), wipe the surface impurities with a dust-free paper, then sequentially use acetone, isopropanol, ethanol and ultrapure water for ultrasonic cleaning for 30 minutes, dry, and treat with ultraviolet ozone before use;

[0084] Step 2, preparation of nickel oxide nanoparticle water dispersion:

[0085] First, prepare the nickel oxide nanoparticle water dispersion, ultrasonic dispersion;

[0086] After spin coating and annealing of the nickel oxide nanoparticle water dispersion, a nickel oxide hole transport layer is obtained;

[0087] Step 3, preparation of SAM solution:

[0088] First, prepare the SAM dispersion, ultrasonic dispersion;

[0089] After spin coating and annealing of the SAM dispersion, a SAM hole transport layer is obtained;

[0090] Step 4, preparation of interface buffer layer:

[0091] After the SAM substrate is annealed to room temperature, spin coating or evaporation of the buffer layer molecules on the SAM substrate, followed by annealing treatment.

[0092] Step 5, preparation of perovskite light absorption layer;

[0093] The three solutes of PbI2: CH(NH2)2I: CsI were weighed and dissolved in a DMSO / DMF mixed solvent; the mixed solution was sealed, fully stirred, and then filtered to obtain a clear perovskite solution for standby;

[0094] The perovskite precursor solution was uniformly coated on the surface of the interface buffer layer substrate; after the perovskite wet film was prepared by spin coating, it was placed on a 100℃ hot stage for 20 minutes to obtain a perovskite light absorption layer;

[0095] Step 6: Preparation of PCBM transport layer:

[0096] After the perovskite film was annealed to room temperature, the PCBM solution was spin-coated on the perovskite substrate to obtain an electron transport layer.

[0097] Step 7, Preparation of BCP blocking layer.

[0098] The BCP solution was spin-coated on the surface of the PCBM layer or a 6 nm BCP layer was vacuum thermal evaporated on the surface of the PCBM.

[0099] Step 7, Silver electrode evaporation: the prepared film was transferred into an evaporation chamber, and a 80 nm thick silver electrode was evaporated using a hot evaporation method. The effective area of the cell mask plate was 0.09 cm 2 .

[0100] Referring to Figure 10 , the battery device photoelectric conversion efficiency test: at room temperature, using a 2400 model solar simulator of Keithley company, the battery efficiency test was carried out under the condition of light intensity of 100 mW / cm 2 (AM 1.5G), through the battery device photoelectric conversion efficiency test, the photoelectric conversion efficiency of the prepared perovskite solar cell was 25.43%.

[0101] Example 3

[0102] Step 1, cleaning FTO glass substrate: select fluorine-doped SnO2 (FTO) transparent conductive glass (2.5*2.5 cm 2 ), wipe the surface impurities with a dust-free paper, then sequentially use acetone, isopropanol, ethanol and ultrapure water for ultrasonic cleaning for 30 minutes, dry, and treat with ultraviolet ozone for standby;

[0103] Step 2, preparation of nickel oxide nanoparticle aqueous dispersion:

[0104] First, the nickel oxide nanoparticle aqueous dispersion was prepared and ultrasonically dispersed;

[0105] After the nickel oxide nanoparticle aqueous dispersion was spin-coated and annealed, a nickel oxide hole transport layer was obtained;

[0106] Step 3, preparation of SAM solution:

[0107] First, prepare the SAM dispersion, ultrasonic dispersion;

[0108] After the SAM dispersion is spin-coated and annealed, the SAM hole transport layer is obtained;

[0109] Step 4, preparation of interface buffer layer:

[0110] After the SAM substrate is annealed to room temperature, the buffer layer molecules are spin-coated or evaporated on the SAM substrate, followed by annealing treatment.

[0111] Step 5, preparation of perovskite light absorption layer;

[0112] Weigh the three solutes of PbI2: CH(NH2)2I: CsI, dissolve them in DMSO / DMF mixed solvent; seal the mixed solution, stir thoroughly, and filter to obtain a clear perovskite solution for use;

[0113] The perovskite precursor solution is uniformly coated on the surface of the interface buffer layer substrate; after spin-coating to obtain the perovskite wet film, it is placed on a 120℃ hot stage for 15 minutes to obtain the perovskite light absorption layer;

[0114] Step 6: Preparation of PCBM transport layer:

[0115] After the perovskite film is annealed to room temperature, the PCBM solution is spin-coated on the perovskite substrate to obtain the electron transport layer.

[0116] Step 7, preparation of BCP barrier layer.

[0117] The BCP solution is spin-coated on the surface of the PCBM layer or a 6 nm thick BCP layer is vacuum evaporated on the surface of the PCBM.

[0118] Step 8, silver electrode evaporation: the prepared film is transferred into the evaporation chamber, and a 90 nm thick silver electrode is evaporated using thermal evaporation method, and the effective area of the mask plate is 0.09 cm 2 .

[0119] Referring to Figure 11 , the battery device photoelectric conversion efficiency test: at room temperature, using a 2400 model solar simulator of Keithley company, under the condition of light intensity of 100 mW / cm 2 (AM 1.5G), the battery efficiency test is carried out, through the battery device photoelectric conversion efficiency test, the photoelectric conversion efficiency of the prepared perovskite solar cell is 25.29%.

[0120] The application also discloses a perovskite solar cell device prepared by the method. x The hole transport layer, the SAM hole transport layer, the interface buffer layer, the perovskite absorption layer, the PCBM electron transport layer, the BCP blocking layer and the silver electrode, wherein the interface buffer agent (a triphenylamine derivative molecule) is integrated at the buried bottom interface of the perovskite layer, due to its symmetrical molecular structure and unique active site (C-N), the formation of iodine vacancy defects is significantly inhibited by the difference coordination with Pb 2+ The interface buffer agent can well adjust the energy level arrangement between the hole transport layer and the perovskite due to its enhanced compatibility. In addition, the multiple rigid structures in the buffer agent molecules effectively constrain the expansion and contraction of the crystal lattice, and reduce the stress accumulation at the interface. By utilizing these advantages, we obtain a low-stress and high-quality perovskite thin film, which is characterized by reduced charge transfer obstacles and inhibited non-radiative recombination processes, and finally obtains a more stable transverse perovskite cell device. The low cost, simple preparation process, excellent photoelectric performance and device efficiency of the transverse perovskite cell device will help to promote the commercial application of perovskite solar cells.

[0121] The above merely describes the preferred embodiments of the present application and is not intended to limit the technical solutions of the present application in any way. Those skilled in the art should understand that the technical solutions can be simply modified and replaced without departing from the spirit and principle of the present application, and these modifications and replacements also belong to the protection scope of the claims.

Claims

1. A method for preparing high efficiency inverted perovskite solar cells based on buried interface stress release, characterized in that, The method comprises the following steps: Step 1, cleaning FTO glass substrate, obtaining pretreated FTO glass substrate; Step 2, spin coating nickel oxide nanoparticle water dispersion on the surface of the pretreated FTO glass substrate, then performing first annealing treatment, obtaining a primary product with a nickel oxide hole transport layer; Step 3, dispersing SAM powder into isopropanol solution to obtain a SAM isopropanol mixed solution, then spin coating the SAM isopropanol mixed solution on the surface of the nickel oxide hole transport layer of the primary product, and then performing second annealing treatment, obtaining a secondary product with a SAM hole transport layer; Step 4, spin coating a triphenylamine derivative molecular solution on the surface of the SAM hole transport layer of the secondary product, and then performing third annealing treatment, obtaining a tertiary product with an interface buffer layer; The preparation of the triphenylamine derivative molecular solution is as follows: dissolving triphenylamine derivative molecular powder in chlorobenzene solution to obtain a triphenylamine derivative molecular solution with a concentration of 0.5-1.5 mg / mL; wherein the structural formula of the triphenylamine derivative molecule is: Step 5, spin coating a perovskite precursor solution on the surface of the interface buffer layer of the tertiary product, obtaining a quaternary product with a perovskite light absorption layer; Step 6, spin coating a PCBM chlorobenzene solution on the perovskite thin film of the quaternary product at room temperature, forming a quinary product with a PCBM electron transport layer; Step 7, preparing a BCP blocking layer on the PCBM electron transport layer of the quinary product, forming a sextuple product with a BCP blocking layer; Step 8, evaporating a silver electrode on the BCP blocking layer of the sextuple product, obtaining a perovskite battery device.

2. The method of claim 1, wherein the buried interface stress release based fabrication of high efficiency perovskite solar cells is characterized by, In step 1, the FTO glass substrate is fluorine-doped SnO2 transparent conductive glass; during cleaning, the FTO glass substrate is sequentially ultrasonically cleaned with acetone solution, isopropanol solution, ethanol solution and ultrapure water, then dried by blowing, and finally treated with ultraviolet ozone to obtain a pretreated FTO glass substrate.

3. The method of claim 1, wherein the buried interface stress release based fabrication of high efficiency perovskite solar cells is characterized by, In step 2, the concentration of nickel oxide nanoparticles in the nickel oxide nanoparticle water dispersion is 0.5-1 mg / mL, the spin coating speed is 3000 r-5000 r / 30 s, and the thickness of spin coating is 10-40 nm; during the first annealing treatment, the temperature is 100-150 ℃, and the time is 30-60 min.

4. The method of claim 1, wherein the buried interface stress release based fabrication of high efficiency perovskite solar cells is characterized by, In step 3, the concentration of the SAM isopropanol mixed solution is 0.5-1.5 mg / mL, the spin coating speed is 2000 r-4000 r / 30 s; during the second annealing treatment, the temperature is 100-150 ℃, and the time is 5-25 min.

5. The method of claim 1, wherein the buried interface stress release based fabrication of high efficiency perovskite solar cells is characterized by, In step 4, during the third annealing treatment, the temperature is 100-150 ℃, and the time is 5-25 min.

6. The method of claim 1, wherein the buried interface stress release based fabrication of high efficiency perovskite solar cells is characterized by, In step 5, the preparation of the perovskite precursor solution is as follows: dissolving PbI2:CH(NH2)2I:CsI with a solute molar ratio of 1:0.98:0.02 in a mixed solvent of DMSO:DMF at a ratio of 1:4 to obtain a perovskite precursor solution; The volume of the perovskite solution dropped during spin coating is 9.6-11 μL / cm2 of the perovskite thin film area 2 ; The thickness of the perovskite light absorption layer is 700-800 nm.

7. The method of claim 1, wherein the buried interface stress release based fabrication of high efficiency trans- perovskite cells is characterized by, In step 6, the volume of the dropwise added electron transport layer solution is 8-9.6 μL / cm2 of the perovskite film area when spin-coating 2 .

8. The method of claim 1, wherein the buried interface stress release based fabrication of high efficiency perovskite solar cells is characterized by, In step 7, the solvent of the BCP solution is isopropanol, and the thickness of the BCP barrier layer is 3-8 nm when spin-coating; the thickness of the BCP barrier layer is 5-15 nm when vacuum thermal evaporation.

9. The method of claim 1, wherein the buried interface stress release based fabrication of high efficiency trans -perovskite cells is characterized by, In step 8, a silver electrode with a thickness of 80-100 nm is deposited by thermal evaporation.

10. A high efficiency perovskite solar cell device obtained by the method of claims 1-9, wherein, The battery device structure is sequentially FTO substrate, NiO x Hole transport layer, SAM hole transport layer, interface buffer layer, perovskite absorption layer, PCBM electron transport layer, BCP blocking layer and silver electrode.

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