Carbon-based organic-inorganic perovskite solar cell based on organic compound modification

Abstract

The invention relates to a carbon-based organic-inorganic perovskite solar cell based on organic compound modification. The solar cell sequentially comprises a transparent conductive substrate, an electron transport layer, an organic compound modification layer, a perovskite layer and a carbon electrode from bottom to top, the material of the organic compound modification layer is [4-(7H-dibenzocarbazole-7-yl) phenyl] phosphoric acid, and the thickness of the organic compound modification layer is 5-10 nm. The obtained perovskite solar cell overcomes the contradiction between reduction of a built-in electric field and maintenance of high PCE of a traditional perovskite solar cell.

Description

Technical Field

[0001] The present invention belongs to the field of semiconductor optoelectronic materials and devices, and particularly relates to an organic-inorganic perovskite solar cell based on organic compound modification of carbon-based materials. Background Art

[0002] With the continuous consumption of traditional energy and the resulting serious environmental pollution problems, vigorously developing new photovoltaic energy technologies has become an important measure to solve energy shortages and environmental pollution. As a new type of energy, solar energy mainly converts light energy into electrical energy through the method of photoelectric conversion, and has many advantages such as environmental protection, rich resources, and clean and renewable. Due to the advantages of high light absorption coefficient, long carrier lifetime, and simple preparation process of perovskite solar cells (PSCs), they have become the focus of research on the new generation of solar cells.

[0003] Carbon materials are regarded as one of the most potential electrode materials for perovskite solar cells due to their rich reserves, low price, good work function matching, and stable properties. In organic-inorganic hybrid perovskite solar cells, carbon materials can effectively improve the battery performance. Since organic-inorganic hybrid metal halides exhibit extremely excellent semiconductor properties, perovskite solar cells have become a very promising candidate in the field of low-cost photovoltaic applications. Currently, the power conversion efficiency (PCE) of this type of battery has successfully climbed to 26.9%, which is comparable to the performance of single-crystalline silicon solar cells. At present, through the vigorous development of large-scale thin-film deposition technology, component production technology, and tandem device technology, the commercialization process of perovskite solar cells is steadily advancing. However, it cannot be ignored that the performance degradation phenomenon occurs during the continuous operation of the battery, which is mainly due to ion migration. The lattice distortion and interface strain caused by ion migration are the main reasons for performance degradation. Therefore, it is urgent to explore an interface modification method to inhibit ion migration, so as to improve the battery stability from the perspective of eliminating the built-in electric field and field response. This structure eliminates charge depletion, built-in electric field, and electric field response in the perovskite absorption layer, which can help stabilize the ion distribution of perovskite. This heterojunction structure can overcome the contradiction of traditional perovskite device structures in reducing the built-in electric field while maintaining a high PCE.

[0004] At present, most interface modifications are achieved by adding inorganic or organic modifiers to achieve a passivation effect, reduce defects in the lower interface of perovskite, and reduce non-radiative recombination of carriers during interface transfer. For example, in the patent (Publication No. 119136575A, a perovskite solar cell based on 1,2PDADI interface modification and its preparation method), 1,2-propanediamine diiodide is coated between the SnO2 electron transport layer and the perovskite absorber layer by spin coating to form a passivation layer, which improves the interface energy level and inhibits interface carrier recombination. However, due to the easy decomposition of the passivation layer, with the increase of service time, problems such as charge accumulation and ion migration may occur at the interface, resulting in a gradual decline in performance. Summary of the Invention

[0005] The object of the present invention is to provide a carbon-based organic-inorganic perovskite solar cell based on organic compound modification in view of the limitations of current technologies. This solar cell uses [4-(7H-dibenzocarbazol-7-yl)phenyl]phosphoric acid (carbazole phosphate) to introduce a heavy p-type (p + ) semiconductor layer between the n-type electron transport layer (ETL) and the perovskite absorber layer, and forms an ETL-p + -perovskite heterojunction by using the mechanism dominated by built-in electric field reconstruction and diffusion separation, thereby eliminating charge depletion, built-in electric field and electric field response in the perovskite absorber layer. The perovskite solar cell obtained by the present invention overcomes the contradiction between reducing the built-in electric field and maintaining high PCE in traditional perovskite solar cells.

[0006] The technical solution of the present invention is as follows:

[0007] A carbon-based organic-inorganic perovskite solar cell based on organic compound modification, which successively includes a transparent conductive substrate, an electron transport layer, an organic compound modification layer, a perovskite layer and a carbon electrode from bottom to top;

[0008] The material of the organic compound modification layer is [4-(7H-dibenzocarbazol-7-yl)phenyl]phosphoric acid, and the thickness is 5-10 nm;

[0009] The transparent conductive substrate is preferably one of fluorine-doped tin oxide transparent conductive glass (FTO), indium tin oxide transparent conductive glass (ITO), PET / ITO (PET is polyethylene terephthalate), and PEN / ITO (PEN is polyethylene naphthalate);

[0010] The electron transport layer is tin dioxide (SnO2), titanium dioxide (TiO2), chlorine-doped titanium dioxide, carbon 60 (C 60) at least one of [6,6]-phenyl C61 butyric acid methyl ester (PCBM), zinc oxide (ZnO), TiO2-SnO2, ZnO-TiO2, ZnO-SnO2; with a thickness of 5 to 180 nm;

[0011] The perovskite layer material has a structural formula of APbX3, where the A site is a formamidinium cation (NH2CH=NH2 + , FA + ), and at least one of methylammonium cation (CH3NH 3+ , MA + ); the X site is at least one of F - , Cl - , Br - , and I - ; with a thickness of 200 to 1000 nm;

[0012] The carbon electrode material is carbon paste, with a sheet resistance < 30 Ω and a solid content of 40 to 60%; with a thickness of 5 to 100 μm.

[0013] The preparation method of the carbon-based organic-inorganic perovskite solar cell based on organic compound modification, this method includes the following steps:

[0014] 1) Prepare an electron transport layer on a transparent conductive substrate;

[0015] 2) Spin-coat a solution of [4-(7H-dibenzocarbazol-7-yl)phenyl]phosphoric acid on the surface of the electron transport layer, and perform annealing treatment to obtain a modified layer;

[0016] The concentration of the [4-(7H-dibenzocarbazol-7-yl)phenyl]phosphoric acid solution is 0.001 to 0.01 mg / mL; the spin-coating speed is 1000 to 6000 rpm, and the spin-coating time is 10 to 60 s; the annealing temperature is 100 to 120 °C, and the treatment time is 5 to 20 min;

[0017] The spin-coating amount is 10 to 200 μL / 4 to 25 cm 2 ;

[0018] 3) Use a spin coater to spin-coat a perovskite precursor solution on the electron transport layer, and perform annealing after treatment with a low-pressure auxiliary device to obtain a perovskite layer;

[0019] The solvent of the perovskite precursor solution is at least one of N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), dimethylacetamide (DMAc), acetonitrile (MeCN), methylammonium acetate, formamidinium formate, butylammonium formate, γ-butyrolactone, absolute ethanol;

[0020] The concentration of the perovskite precursor solution is 0.2 to 2 mol / L, calculated based on the content of Pb;

[0021] 4) Spin-coat a carbon paste on the surface of the perovskite layer, and then perform annealing treatment to finally obtain a carbon-based perovskite solar cell with an organic compound-modified perovskite lower interface.

[0022] In step 2), the preparation method of the [4-(7H-dibenzocarbazol-7-yl)phenyl]phosphoric acid solution is to add [4-(7H-dibenzocarbazol-7-yl)phenyl]phosphoric acid particles to ethanol to obtain a solution;

[0023] In step 3), the spin-coating speed is 1000 to 6000 rpm, and the spin-coating time is 10 to 60 s; when the low-pressure auxiliary equipment is used, the vacuum degree is 1 to 100 Pa, and the treatment time is 1 to 60 s; the annealing temperature is 100 to 120 °C, and the treatment time is 5 to 20 min;

[0024] In step 4), the annealing temperature is 100 to 120 °C, and the treatment time is 15 to 20 min;

[0025] The substantial features of the present invention are:

[0026] Through research, it is found that there is serious ion migration in carbon-based organic-inorganic hybrid perovskite solar cells. The long-distance migration and local accumulation of ions will induce lattice distortion and interfacial strain, thereby changing the atomic coordination of the interface, which has a very great impact on the operating stability of the battery.

[0027] The present invention uses a [4-(7H-dibenzocarbazol-7-yl)phenyl]phosphoric acid solution, which is spin-coated on the lower interface of a carbon-based normal-hole-free perovskite solar device to form a heterojunction n-p + -i, that is, a heavy p-type (p + ) semiconductor layer is introduced between the n-type electron transport layer (ETL) and the perovskite absorption layer to form an ETL-p + -perovskite heterojunction. This heterojunction plays the role of reconstructing the built-in electric field. The principle is that the n-type material and the p-type material combine to form a p-n junction, forming a space depletion region, thereby generating a built-in electric field (n-p + ). At this time, this built-in electric field makes the perovskite absorption layer neutral, eliminating charge depletion, built-in electric field and electric field response in the perovskite absorption layer. Therefore, it can help stabilize the ion distribution of perovskite and improve the stability of the battery. Although the perovskite absorption layer is neutral, the photo-generated carriers are mainly transported through the diffusion mechanism, and the carrier diffusion length is relatively long, suppressing the recombination of interfacial charges, and the battery can still obtain a very high PCE. This new type of heterojunction device structure overcomes the contradiction between reducing the built-in electric field and maintaining a high PCE.

[0028] The beneficial effects of the present invention are as follows:

[0029] 1) Compared with the traditional method of spin-coating a conventional modification layer on the electron transport layer of a carbon-based hole-free inverted perovskite to form an n-i structure, the present invention uses a p-type material to form an ETL-p + -perovskite heterojunction. Charge depletion and built-in electric fields mainly exist in the ETL and p + layers, while the perovskite absorption layer remains in a neutral state. The neutral perovskite absorption layer can inhibit ion migration, thereby improving the stability performance of the device. Stored for 30 days under unencapsulated conditions: the efficiency of the modified battery remains 95.4% of the initial value (Example 1), while that of the unmodified battery is only 85% (Comparative Case 9), and the stability is improved by 12.2% ( Figure 2 ).

[0030] 2) Compared with the standard sample without organic compound modification, the present invention has a lower ion mobility, and the lattice distortion and interfacial strain caused by ion migration are also reduced. The lifetime is increased, the open-circuit voltage is increased by 8.22%, the fill factor is increased by 3.89%, and the photoelectric conversion efficiency is increased by 24.27%. The improvement effect is obvious. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic structural diagram of the solar cell of Example 1; wherein, 1 is a transparent conductive substrate, 2 is an electron transport layer, 3 is an organic compound modification layer, 4 is a perovskite layer, and 5 is a carbon electrode;

[0032] Figure 2 The solid line in it is the stability test curve of the carbon-based perovskite solar cell device with the perovskite lower interface modified by an organic compound prepared in Example 1 under un-sealed conditions; the dotted line is the stability test curve of the carbon-based perovskite solar cell device without the perovskite lower interface modified by an organic compound prepared in Example 9 (comparative case) under un-sealed conditions;

[0033] Figure 3 The solid line in it is the J-V test curve graph of the carbon-based perovskite solar cell device with the perovskite lower interface modified by an organic compound prepared in Example 1; the dotted line is the J-V test curve graph of the carbon-based perovskite solar cell device without the perovskite lower interface modified by an organic compound prepared in Example 9 (comparative case). SPECIFIC IMPLEMENTATION METHODS

[0034] Example 1.

[0035] A carbon-based perovskite solar cell based on the modification of the perovskite lower interface with an organic compound. The schematic structural diagram of the solar cell is as Figure 1As shown, from bottom to top are a transparent conductive substrate, an electron transport layer, an organic compound modification layer, a perovskite layer, and a carbon electrode. The specific preparation process is as follows:

[0036] Step 1. Clean the FTO substrate:

[0037] The FTO (2.5 cm × 2.5 cm) transparent conductive substrate used in this example has an average light transmittance of 90%. The FTO substrate is ultrasonically cleaned with glass cleaning agent, deionized water, and alcohol for 30 minutes in sequence, and then dried with a nitrogen gun.

[0038] Step 2. Prepare the SnO2 electron transport layer:

[0039] Weigh 625 mg of urea and 137.5 mg of SnCl2·2H2O with a balance and put them into a blue-mouth bottle. Then, successively add 625 μL of HCl, 12.5 μL of TGA, and 50 mL of deionized water with a pipette gun and mix evenly to obtain the SnO2 growth solution for standby.

[0040] Immerse the cleaned FTO substrate into the staining dish filled with the SnO2 growth solution, place it in an oven at 90 °C for 4 hours, and then take it out. Ultrasonically clean it with deionized water for 5 minutes, and then dry its surface with a nitrogen gun; then perform annealing treatment (annealing temperature 170 °C, annealing time 60 minutes), and finally obtain the electron transport layer SnO2 with a thickness of 30 nm.

[0041] Step 3. Prepare the [4-(7H-dibenzocarbazol-7-yl)phenyl]phosphoric acid modification layer:

[0042] Weigh 1 mg of [4-(7H-dibenzocarbazol-7-yl)phenyl]phosphoric acid solid with an electronic balance, add it to a reagent glass bottle, and then add 1000 mL of ethanol to obtain a solution with a concentration of 0.001 mg / mL. Place the annealed device from the previous step on a spin coater for adsorption. After dropping 100 μL on the SnO2 electron transport layer, spin it at 4000 rmp for 30 s, and then anneal it at 100 °C for 10 minutes; the thickness is 5 nm.

[0043] Step 4. Prepare FA 0.3 MA 0.7 PbI3 perovskite layer:

[0044] Prepare 1.33 mol / L FA 0.3 MA 0.7PbI3 perovskite precursor solution, the concentration is based on the content of lead, specifically including solutes formamidinium iodide (FAI), methylammonium iodide (MAI), and lead iodide (PbI2), with molar amounts of 0.36 mmol, 0.84 mmol, and 1.2 mmol respectively. 100 μL of NMP and 800 μL of DMF are sequentially added as solvents to obtain 900 μL of perovskite precursor solution.

[0045] Using a spin coater, spin coat the prepared perovskite precursor solution on the organic compound modified layer. First, spin coat at 2500 rpm for 10 s, then at 4500 rpm for 10 s, and then immediately place it in a low-pressure auxiliary system (DL-10A type quartz vacuum gauge and vacuum pump) for low-pressure (vacuum degree of 10 Pa) treatment for 60 s to quickly volatilize the solvent, thereby obtaining a well-crystallized intermediate phase thin film. After the low-pressure treatment, anneal on a heating table at 120 °C for 20 min to obtain a well-crystallized perovskite thin film (thickness of 600 nm). Among them, the volume of the spin-coated perovskite precursor is 60 μL.

[0046] Step Five: Prepare the carbon electrode:

[0047] Stick two 3M tapes on the surface of the perovskite layer to control the thickness of the carbon electrode, leaving a rectangular gap with a width of 0.3 cm and a length of 2.5 cm in the middle. Take 50 mg of low-temperature carbon paste (sheet resistance < 30 ohms, solid content of 50%, cleaning agent is cyclohexanone, CAS number is 7440-44-0. The same applies to the following examples and will not be repeated) and put it into the gap, and scrape it multiple times in the same direction with a blade until the gap is completely filled. The area of the scraped carbon electrode is 0.3 cm × 2.5 cm, and then anneal on a heating table at 100 °C for 15 min; the thickness is 10 μm.

[0048] In this example, four measurement points are taken for a single-carbon electrode perovskite solar cell, and the effective area of each measurement point is 0.09 cm 2 .

[0049] In this example, a solar simulator is used to select a K-2400 light source to simulate AM 1.5G illumination for J-V testing of a carbon-based perovskite solar cell with [4-(7H-dibenzocarbazol-7-yl)phenyl]phosphoric acid modified on the lower interface of the perovskite layer, as Figure 3 shown by the solid line in. From the J-V curve, the photoelectric conversion efficiency of the solar cell is 11.21%, and the open-circuit voltage, short-circuit current density, and fill factor are 0.79 V, 25.08 mA / cm 2 and 56.09% respectively.

[0050] Example 2:

[0051] Carbon-based perovskite solar cells with an organic compound-modified perovskite lower interface, and other steps are the same as in Example 1, except that:

[0052] In the preparation of the solution in Step 3, 2 mg of [4-(7H-dibenzocarbazol-7-yl)phenyl]phosphonic acid was added to 1000 mL of ethanol, and the concentration was 0.002 mg / mL.

[0053] Example 3:

[0054] Carbon-based perovskite solar cells with an organic compound-modified perovskite lower interface, and other steps are the same as in Example 1, except that:

[0055] In the preparation of the solution in Step 3, 3 mg of [4-(7H-dibenzocarbazol-7-yl)phenyl]phosphonic acid was added to 1000 mL of ethanol, and the concentration was 0.003 mg / mL.

[0056] Example 4:

[0057] Carbon-based perovskite solar cells with an organic compound-modified perovskite lower interface, and other steps are the same as in Example 1, except that:

[0058] In the preparation of the solution in Step 3, 4 mg of [4-(7H-dibenzocarbazol-7-yl)phenyl]phosphonic acid 4 was added to 1000 mL of ethanol, and the concentration was 0.004 mg / mL.

[0059] Example 5.

[0060] Carbon-based perovskite solar cells with an organic compound-modified perovskite lower interface, and other steps are the same as in Example 1, except that:

[0061] In the preparation of the perovskite layer in Step 4, the perovskite layer is FAPbI3, and the concentration is 1.33 mol / L, which is calculated based on the content of lead. Specifically, the solutes are formamidinium iodide, lead iodide, and methylammonium chloride, and the molar amounts are 1.2 mmol, 1.2 mmol, and 0.18 mmol, respectively. 100 μL of NMP and 800 μL of DMF were added as solvents in sequence to obtain 900 μL of perovskite precursor solution.

[0062] Example 6.

[0063] Carbon-based perovskite solar cells with an organic compound-modified perovskite lower interface, and other steps are the same as in Example 1, except that:

[0064] In Step 4, the perovskite layer is prepared. The perovskite layer is MAPbI3 with a concentration of 1.33 mol / L, which is based on the content of lead. Specifically, the solutes are methylammonium iodide, lead iodide, and methylammonium chloride, with molar amounts of 1.2 mmol, 1.2 mmol, and 0.18 mmol, respectively. 100 μL of NMP and 800 μL of DMF are sequentially added as solvents to obtain 900 μL of perovskite precursor solution.

[0065] Example 7.

[0066] For the carbon-based perovskite solar cell with an organic compound-modified perovskite lower interface, other steps are the same as in Example 1, except that:

[0067] In Step 4, the perovskite layer is prepared. The perovskite layer is FA 0.85 MA 0.15 PbI3 with a concentration of 1.33 mol / L, which is based on the content of lead. Specifically, the solutes are formamidinium iodide, methylammonium iodide, lead iodide, and methylammonium chloride, with molar amounts of 1.02 mmol, 0.18 mmol, 1.2 mmol, and 0.18 mmol, respectively. 100 μL of NMP and 800 μL of DMF are sequentially added as solvents to obtain 900 μL of perovskite precursor solution.

[0068] Example 8.

[0069] For the carbon-based perovskite solar cell with an organic compound-modified perovskite lower interface, other steps are the same as in Example 1, except that:

[0070] In Step 3, the solution of [4-(7H-dibenzocarbazol-7-yl)phenyl]phosphonic acid is prepared by adding 2 mg of [4-(7H-dibenzocarbazol-7-yl)phenyl]phosphonic acid to 1000 mL of ethanol, with a concentration of 0.002 mg / mL;

[0071] In Step 4, the perovskite layer is prepared. The perovskite layer is FA 0.85 MA 0.15 PbI3 with a concentration of 1.33 mol / L, which is based on the content of lead. Specifically, the solutes are formamidinium iodide, methylammonium iodide, lead iodide, and methylammonium chloride, with molar amounts of 1.02 mmol, 0.18 mmol, 1.2 mmol, and 0.18 mmol, respectively. 100 μL of NMP and 800 μL of DMF are sequentially added as solvents to obtain 900 μL of perovskite precursor solution.

[0072] Example 9. (Comparative case)

[0073] For the carbon-based perovskite solar cell with an organic compound-modified perovskite lower interface, other steps are the same as in Example 1, except that:

[0074] Omit the operation in Step 3, without preparing the organic compound modification layer, and directly spin-coat the perovskite layer on the surface of the electron transport layer.

[0075] In this embodiment, a K-2400 light source is selected by a solar simulator to simulate AM 1.5G illumination for J-V testing of the carbon-based perovskite solar cell with the lower interface of the perovskite layer not modified by [4-(7H-dibenzocarbazol-7-yl)phenyl]phosphoric acid, as Figure 3 shown by the dashed line in the figure. From the J-V curve, the photoelectric conversion efficiency of the solar cell is 9.02%, and the open-circuit voltage, short-circuit current density, and fill factor are 0.73 V, 22.69 mA / cm 2 and 53.99% respectively.

[0076] Through the comparison of the device test parameters in Example 1 and Example 9 (comparative example), it shows that in the carbon-based organic-inorganic hybrid perovskite solar cell, introducing a [4-(7H-dibenzocarbazol-7-yl)phenyl]phosphoric acid modification layer between the electron transport layer and the perovskite layer by spin-coating can significantly improve the photoelectric conversion efficiency of the device.

[0077] The present invention is not limited to the above embodiments and can be varied within the scope of the claims. The above embodiments and the descriptions in the specification only illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

[0078] Matters not covered by the present invention are well-known technologies.

Claims

1. A carbon-based organic-inorganic perovskite solar cell modified by an organic compound, characterized in that, The solar cell, from bottom to top, successively comprises a transparent conductive substrate, an electron transport layer, an organic compound modification layer, a perovskite layer, and a carbon electrode; The material of the organic compound modification layer is [4-(7H-dibenzocarbazol-7-yl)phenyl]phosphonic acid, and the thickness is 5-10 nm.

2. The carbon-based organic-inorganic perovskite solar cell modified with an organic compound as claimed in claim 1, characterized in that, The transparent conductive substrate is one of fluorine-doped tin oxide transparent conductive glass (FTO), indium tin oxide transparent conductive glass (ITO), PET / ITO (PET is polyethylene terephthalate), and PEN / ITO (PEN is polyethylene naphthalate); The electron transport layer described above is at least one of tin dioxide (SnO2), titanium dioxide (TiO2), chlorine-doped titanium dioxide, fullerene (C 60 ), [6,6]-phenyl C61 butyric acid methyl ester (PCBM), zinc oxide (ZnO), TiO2-SnO2, ZnO-TiO2, ZnO-SnO2; and has a thickness of 5 to 180 nm; The structural formula of the perovskite layer material is APbX3, where the A site is at least one of formamidinium cation (NH2CH=NH2 + , FA + ) and methylammonium cation (CH3NH 3+ , MA + ); the X site is at least one of F - , Cl - , Br - and I - ; and the thickness is 200 - 1000 nm.

3. The carbon-based organic-inorganic perovskite solar cell modified by an organic compound as claimed in claim 1, wherein, The carbon electrode material is carbon paste, with a sheet resistance <30 Ω, a solid content of 40-60%; and a thickness of 5-100 μm.

4. The preparation method of the carbon-based organic-inorganic perovskite solar cell modified by an organic compound according to claim 1, characterized in that, The method comprises the following steps: 1) Prepare an electron transport layer on the transparent conductive substrate; 2) Spin-coat a [4-(7H-dibenzocarbazol-7-yl)phenyl]phosphonic acid solution on the surface of the electron transport layer, and perform annealing treatment to obtain a modification layer; The concentration of the [4-(7H-dibenzocarbazol-7-yl)phenyl]phosphonic acid solution is 0.001-0.01 mg / mL; the spin-coating speed is 1000-6000 rpm, and the spin-coating time is 10-60 s; the annealing temperature is 100-120 °C, and the treatment time is 5-20 min; The spin coating amount is 10 to 200 μL / 4 to 25 cm 2 ; 3) Spin-coat a perovskite precursor solution on the electron transport layer using a spin coater, perform annealing after treatment by a low-pressure auxiliary device to obtain a perovskite layer; The solvent of the perovskite precursor solution is at least one of N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), dimethylacetamide (DMAc), acetonitrile (MeCN), methylammonium acetate, methylammonium formate, butylammonium methylammonium, γ-butyrolactone, and absolute ethanol; The concentration of the perovskite precursor solution is 0.2-2 mol / L, calculated based on the content of Pb; 4) Knife-coat carbon paste on the surface of the perovskite layer, and then perform annealing treatment to finally obtain a carbon-based perovskite solar cell based on the lower interface of the perovskite modified by an organic compound.

5. The preparation method of the organic-inorganic perovskite solar cell based on organic compound-modified carbon as claimed in claim 4, characterized in that, In step 2), the solvent of the [4-(7H-dibenzocarbazol-7-yl)phenyl]phosphonic acid solution is ethanol.

6. The preparation method of the carbon-based organic-inorganic perovskite solar cell modified by an organic compound according to claim 4, characterized in that, In step 3), the spin-coating speed is 1000-6000 rpm, and the spin-coating time is 10-60 s; the vacuum degree during the treatment by the low-pressure auxiliary device is 1-100 Pa, and the treatment time is 1-60 s; the annealing temperature is 100-120 °C, and the treatment time is 5-20 min.

7. The preparation method of the carbon-based organic-inorganic perovskite solar cell modified by an organic compound according to claim 4, characterized in that, In step 4), the annealing temperature is 100-120 °C, and the treatment time is 15-20 min.

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