Amido additive and application thereof in preparation of perovskite solar cell

Abstract

The invention provides an amide-based additive and an application thereof in preparation of a perovskite solar cell. The molecular structural formula of the acylamino additive is shown as a formula I; r in the formula I is selected from any one of-H,-CH2OH,-CH2Cl and-CH = CH2. According to the invention, the amide-based additive is used in the hole transport layer and the perovskite light absorption layer and can be neutralized with PEDOT / PSS of the hole transport layer in the narrow-band-gap perovskite solar cell, so that the reaction between the PEDOT / PSS and perovskite is slowed down, and the growth of perovskite grains is promoted. Meanwhile, when the film is used for a narrow-band-gap perovskite light absorption layer, an amide group can be oxidized into carboxylic acid, oxidation of Sn < 2 + > in a perovskite precursor is avoided, and the defects of the film are reduced; the Pb vacancy is filled and combined by an amide group when the Pb vacancy is applied to a wide-band-gap perovskite absorption layer, so that the defect of a passivated film is improved; therefore, the perovskite energy level is better matched, the film quality is improved, and the photoelectric conversion efficiency and the stability of the perovskite solar cell can be remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic cell technology, specifically to an amide-based additive and its application in the preparation of perovskite solar cells. Background Technology

[0002] Metal halide perovskite solar cells are a new discovery that theoretically surpasses crystalline silicon cells in efficiency and costs less than crystalline silicon cells, marking perovskite solar cells as one of the focal points of next-generation photovoltaic power generation.

[0003] Recently, the power conversion efficiency of single-junction perovskite solar cells has been certified to reach 26.7%. In single-junction solar cells, efficiency is mainly limited by the thermal loss of photons above the bandgap and the inability to absorb photons below the bandgap. Therefore, to break through the efficiency limit, tandem solar cells can be constructed by stacking wide-bandgap cells with narrow-bandgap cells. This maximizes the utilization of both short-wavelength and long-wavelength solar spectra, effectively reducing the aforementioned losses and significantly improving cell efficiency. The theoretical efficiency of tandem cells can reach 45%, far exceeding the Shockley-Quesel (SQ) limit efficiency of approximately 34% for single-junction cells.

[0004] To improve photoelectric conversion efficiency, more and more researchers are beginning to delve into tandem solar cells combining perovskite solar cells with other solar cells, such as perovskite-crystalline silicon tandem solar cells, perovskite-perovskite tandem solar cells, and perovskite-organic tandem solar cells. In all-perovskite tandem solar cells, narrow-bandgap perovskite solar cells serve as the bottom cell; therefore, improving the efficiency and stability of narrow-bandgap perovskite solar cells has become crucial for the development of all-perovskite tandem solar cell technology.

[0005] Narrow bandgap perovskites typically have band gaps between 1.22 eV and 1.28 eV. Traditional Pb-based perovskites, on the other hand, are usually composed of FAPbI3, with band gaps typically around 1.55 eV. Therefore, to reduce the band gap, Sn is generally used. 2+ To replace part of Pb 2 + However, in narrow bandgap perovskite solar cells, Sn 2+ It is very unstable and readily oxidizes to Sn. 4+ This results in a large number of vacancy defects; simultaneously, the different crystallization rates of Sn and Pb ions also deteriorate the crystallization quality of perovskite; furthermore, the sulfonic acid groups in poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), a commonly used hole transport layer material in narrow bandgap perovskite solar cells, are strongly acidic and readily react with tin-lead perovskite, accelerating the reaction of Sn... 2+Oxidation leads to instability and decomposition of perovskite. These adverse factors severely hinder carrier transport, causing p-type self-doping, which in turn leads to increased non-radiative recombination, affecting the further improvement of photoelectric conversion efficiency and stability of narrow-bandgap perovskite solar cells and all-perovskite tandem solar cells. Summary of the Invention

[0006] (a) Technical problems to be solved

[0007] To address the shortcomings of existing technologies, this invention provides an amide-based additive and its application in the fabrication of perovskite solar cells. By using the amide-based additive in the hole transport layer of narrow-bandgap perovskite solar cells and the perovskite light-absorbing layer of both narrow-bandgap and wide-bandgap perovskite solar cells, the problems mentioned in the background art are solved.

[0008] (II) Technical Solution

[0009] To achieve the above objectives, the present invention provides the following technical solution:

[0010] According to a first aspect of the present invention, an amide-based additive is provided, the molecular structure of which is shown in Formula I;

[0011]

[0012] In formula I, R is selected from -H, -CH2OH, Either -CH2Cl or -CH=CH2.

[0013] According to a second aspect of the present invention, an application of an amide-based additive in the fabrication of a perovskite solar cell is provided, the perovskite solar cell comprising a narrow bandgap perovskite solar cell, a wide bandgap solar cell, and an all-perovskite tandem solar cell.

[0014] A method for fabricating a narrow bandgap perovskite solar cell includes the following steps:

[0015] (1) A conductive polymer containing amide additives is spin-coated onto a conductive glass layer and then annealed to obtain a hole transport layer.

[0016] (2) Spin-coating a tin-lead perovskite precursor solution containing amide-based additives onto the hole transport layer and annealing it to obtain a perovskite light-absorbing layer.

[0017] (3) First, C is deposited on the perovskite light-absorbing layer. 60 Alternatively, PCBM is used to obtain a lower electron transport layer with a thickness of 20nm, followed by the deposition of BCP or SnO2 to obtain an upper electron transport layer with a thickness of 7nm.

[0018] (4) Metal is deposited on the upper electron transport layer to obtain a metal electrode layer.

[0019] Preferably, in step (1), the conductive polymer in the conductive polymer containing amide additive is PEDOT:PSS;

[0020] The concentration of the amide group additive in the conductive polymer containing the amide group additive is 5-10 mg / mL;

[0021] Specifically, in step (1), the spin coating speed is 5000 rpm and the spin coating time is 30 s;

[0022] The annealing temperature was 100℃ and the time was 20 minutes.

[0023] Preferably, in step (2), the tin-lead perovskite precursor solution containing amide-based additives is selected from FA. n MA 1-n Pb x Sn 1-x I3 precursor solution or FA n Cs 1-n Pb x Sn 1-x I3 precursor solution, the FA n MA 1-n Pb x Sn 1-x I3 precursor solution and FA n Cs 1-n Pb x Sn 1-x In the I3 precursor solution, n satisfies 0 ≤ n ≤ 1, and x satisfies 0 ≤ x ≤ 1;

[0024] The concentration of the amide group additive in the tin-lead perovskite precursor solution containing the amide group additive is 1-3 mg / mL.

[0025] Specifically, in step (2), the spin coating and annealing process is as follows: first spin coating at 1000 rpm for 10 s, then spin coating at 5000 rpm for 40 s, add 400 μL of chlorobenzene for extraction in the last 20 s of the total spin coating time, and finally place on a heating platform for annealing at 100℃ for 10 min.

[0026] A method for fabricating a wide-bandgap perovskite solar cell includes the following steps:

[0027] S1. Spin-coat the first liquid precursor solution onto the conductive glass layer, and perform a first annealing treatment to obtain the lower hole transport layer. Then spin-coat the second liquid precursor solution onto the lower hole transport layer, and perform a second annealing treatment to obtain the upper hole transport layer.

[0028] S2, FA containing amide group additives n Cs 1-n Pb(I x Br 1-x )3. The precursor solution is spin-coated onto the hole transport layer and annealed to obtain a perovskite light-absorbing layer.

[0029] S3. First, C is deposited on the perovskite light-absorbing layer. 60 Alternatively, PCBM is used to obtain a lower electron transport layer with a thickness of 20nm, followed by the deposition of BCP or SnO2 to obtain an upper electron transport layer with a thickness of 7nm.

[0030] S4. Metal is deposited on the upper electron transport layer to obtain a metal electrode layer.

[0031] Preferably, in step S1, the first liquid precursor solution comprises water and PTAA, PTPD, 2PACz, 4PACz, 6PACz, Meo-2PACz, Meo-4PACz, Meo-6PACz and NiO. X Any mixture of solutions;

[0032] The second liquid precursor solution includes a mixed solution of methanol and any one of Me-2PACz, Me-4PACz and Me-6PACz.

[0033] Specifically, in an air atmosphere, the first liquid precursor solution is spin-coated onto the conductive glass layer at a speed of 2000 rpm for 30 seconds, and then annealed at 200°C for 10 minutes to obtain the lower hole transport layer; in a nitrogen atmosphere, the second liquid precursor solution is spin-coated onto the lower hole transport layer at a speed of 3000 rpm for 30 seconds, and then annealed at 100°C for 10 minutes to obtain the upper hole transport layer.

[0034] Preferably, the FA containing amide-based additives n Cs 1-n Pb(I x Br 1-x )3 The concentration of amide additive in the precursor solution is 1-3 mg / mL.

[0035] Specifically, in step S2, the spin coating annealing process is as follows: first spin coating at 1000 rpm for 10 seconds, then spin coating at 3000 rpm for 40 seconds, add 100 μL of chloroform dropwise for extraction at the 12th second to last of the total spin coating time, and finally place on a heating platform to anneal at 100°C for 10 minutes.

[0036] A method for fabricating an all-perovskite tandem solar cell includes the following steps:

[0037] A. Spin-coat the first liquid precursor solution onto the conductive glass layer, and perform a first annealing treatment to obtain the first hole transport layer. Then spin-coat the second liquid precursor solution onto the first hole transport layer, and perform a second annealing treatment to obtain the second hole transport layer.

[0038] B. FA containing amide-based additives n Cs 1-n Pb(I x Br 1-x )3 The precursor solution was spin-coated onto the second hole transport layer and annealed to obtain a wide-bandgap perovskite light-absorbing layer.

[0039] C. First, deposit C on the surface of the wide-bandgap perovskite light-absorbing layer. 60 Alternatively, PCBM is used to obtain a first electron transport layer with a thickness of 20 nm, followed by atomic deposition of SnO2 to obtain a second electron transport layer with a thickness of 7 nm.

[0040] D. Deposit Au or IZO nanoparticles on the surface of the second electron transport layer to obtain the first metal electrode layer;

[0041] E. Spin-coating a conductive polymer containing amide additives onto the first metal electrode layer and annealing it to obtain a third hole transport layer.

[0042] F. Spin-coat the tin-lead perovskite precursor solution containing amide-based additives onto the third hole transport layer, and anneal it to obtain a narrow bandgap perovskite light-absorbing layer.

[0043] G. First, deposit C on the narrow bandgap perovskite light-absorbing layer. 60 Alternatively, PCBM is used to obtain a third electron transport layer with a thickness of 20 nm, followed by the deposition of BCP or SnO2 to obtain a fourth electron transport layer with a thickness of 7 nm.

[0044] H. Deposit metal onto the fourth electron transport layer to obtain a second metal electrode layer.

[0045] The all-perovskite tandem solar cell of this invention is prepared by stacking narrow-bandgap perovskite solar cells and wide-bandgap perovskite solar cells, wherein the preparation method is the same as that for narrow-bandgap perovskite solar cells and wide-bandgap perovskite solar cells.

[0046] Beneficial effects

[0047] This invention provides an amide-based additive and its application in the fabrication of perovskite solar cells. It offers the following advantages:

[0048] This solution provides an amide-based additive and its application in the fabrication of perovskite solar cells. Because the amino group of the amide group in the additive is weakly basic, it can neutralize PEDOT:PSS in the hole transport layer of narrow-bandgap perovskite solar cells, slowing down the reaction between PEDOT:PSS and perovskite, reducing interface defects at the perovskite buried interface, and promoting perovskite grain growth. Simultaneously, when used in the perovskite light-absorbing layer of narrow-bandgap perovskite solar cells, the amide group is oxidized to a carboxylic acid, which can reduce the Sn content in the perovskite precursor. 2+ Oxidation reduces film defects; in the perovskite absorber layer of wide-bandgap perovskite solar cells, amide groups fill and bind to Pb vacancies, thereby improving passivation of film defects; thus, the perovskite energy levels are better matched, the film quality is improved, and the photoelectric conversion efficiency and stability of single-junction perovskite solar cells and all-perovskite tandem cells can be significantly improved. Attached Figure Description

[0049] Figure 1 This is a schematic diagram of the narrow bandgap perovskite solar cell prepared in Example 1 of the present invention;

[0050] Figure 2 This is a schematic diagram of the structure of the wide-bandgap perovskite solar cell prepared in Example 3 of the present invention;

[0051] Figure 3 This is a schematic diagram of the structure of the all-perovskite tandem solar cell prepared in Example 4 of the present invention;

[0052] Figure 4 This is a cross-sectional SEM image of the narrow bandgap perovskite solar cell prepared in Example 1 of the present invention;

[0053] Figure 5 Here is a surface SEM image of the narrow bandgap perovskite solar cell prepared in Example 1 of this invention;

[0054] Figure 6 This is a cross-sectional SEM image of the narrow bandgap perovskite solar cell prepared in Comparative Example 1 of this invention.

[0055] Figure 7 The efficiency statistics of the narrow bandgap perovskite solar cells prepared in Examples 1-2 and Comparative Example 1 of this invention are shown in the figure.

[0056] Figure 8 The JV diagrams are for the narrow bandgap perovskite solar cells prepared in Examples 1-2 and Comparative Example 1 of this invention.

[0057] Figure 9 The JV diagram is shown for the wide-bandgap perovskite solar cell prepared in Example 3 of this invention.

[0058] Figure 10The JV diagram is shown for the all-perovskite tandem solar cell prepared in Example 4 of this invention.

[0059] Figure 11 The diagram shows the long-term stability of the narrow bandgap perovskite solar cells prepared in Examples 1-2 and Comparative Example 1 of this invention.

[0060] In the figure, 1 is the conductive glass layer; 2 is the hole transport layer; 3 is the perovskite light-absorbing layer; 4 is the electron transport layer; 5 is the metal electrode layer; 6 is the first hole transport layer; 7 is the second hole transport layer; 8 is the wide bandgap perovskite light-absorbing layer; 9 is the first electron transport layer; 10 is the second electron transport layer; 11 is the first metal electrode layer; 12 is the third hole transport layer; 13 is the narrow bandgap perovskite light-absorbing layer; 14 is the third electron transport layer; 15 is the fourth electron transport layer; and 16 is the second metal electrode layer. Detailed Implementation

[0061] To better illustrate the content of this invention, the following description is provided in conjunction with specific embodiments.

[0062] This invention provides an amide-based additive, the molecular structure of which is shown in Formula I:

[0063]

[0064] In formula I, R is selected from -H, -CH2OH, Either -CH2Cl or -CH=CH2.

[0065] The amide-based additives provided in this application are used in the fabrication process of perovskite solar cells. Specifically, they are used in the hole transport layer and perovskite light-absorbing layer of narrow bandgap perovskite solar cells, the perovskite light-absorbing layer of wide bandgap perovskite solar cells, and all-perovskite tandem cells that combine narrow bandgap perovskite solar cells and wide bandgap perovskite solar cells.

[0066] This invention provides a narrow bandgap perovskite solar cell, comprising, from bottom to top, a conductive glass layer, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer, and a metal electrode layer, wherein the conductive glass layer is selected from ITO conductive glass layer or FTO conductive glass layer; the hole transport layer is a PEDOT / PSS layer; and the perovskite light-absorbing layer is selected from FTO. n MA 1-n Pb x Sn 1-x I3 layer or FA n Cs 1-n Pb x Sn 1-x I3 layer; the lower electron transport layer is selected from C. 60The film or PCBM film has an electron transport layer selected from BCP film or SnO2 film; the metal electrode layer is selected from gold film, silver film or copper film.

[0067] This invention provides a wide-bandgap perovskite solar cell, comprising, from bottom to top, a conductive glass layer, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer, and a metal electrode layer, wherein the conductive glass layer is selected from ITO conductive glass layer or FTO conductive glass layer; the hole transport layer includes a lower hole layer and an upper hole layer, the lower hole layer including PTAA, PTPD, 2PACz, 4PACz, 6PACz, Meo-2PACz, Meo-4PACz, Meo-6PACz, and nickel oxide NiO. X Any one of the following, where x takes the value 2 or 3; the upper hole layer includes any one of Me-2PACz, Me-4PACz, and Me-6PACz; the perovskite light-absorbing layer is FA. n Cs 1-n Pb(I x Br 1-x )3 layers; the electron transport layer includes a lower transport layer and an upper transport layer, the lower transport layer includes C 60 Alternatively, a PCBM may be used, with the upper transport layer comprising Au and IZO nanoparticles; the metal electrode layer is selected from gold, silver, or copper films.

[0068] The technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0069] Example 1

[0070] A narrow bandgap perovskite solar cell, the structure of which is shown in the figure below. Figure 1 As shown, it includes a conductive glass layer 1, a hole transport layer 2, a perovskite light-absorbing layer 3, an electron transport layer 4, and a metal electrode layer 5, which are stacked sequentially from bottom to top.

[0071] The specific fabrication method of the narrow bandgap perovskite solar cell in this embodiment is as follows:

[0072] Step 1: Clean and dry the 2cm×2cm ITO conductive glass layer;

[0073] Step 2: Add hydroxyacetamide to PEDOT:PSS conductive polymer until the concentration of hydroxyacetamide in the conductive polymer reaches 5 mg / mL. Spin-coat 75 μL of conductive polymer onto the ITO conductive glass layer at a speed of 5000 rpm for 30 s. Anneal at 140℃ for 20 min to obtain the hole transport layer.

[0074] Step 3: Add FAI, MAI, SnI2, PbI2, and SnF2 to an organic solvent of N,N-dimethylformamide and dimethyl sulfoxide, then add hydroxyacetamide, and stir at 50°C for 60 min to obtain a perovskite precursor solution. In the perovskite precursor solution, the volume ratio of N,N-dimethylformamide to dimethyl sulfoxide is 3:1, the concentration of hydroxyacetamide is 1 mg / mL, the concentration of FAI is 1.1 mol / L, the concentration of MAI is 1.1 mol / L, the concentration of SnI2 is 1.1 mol / L, the concentration of PbI2 is 1.1 mol / L, and the concentration of SnF2 is 0.1 mol / L.

[0075] Step 4: Spin coat 50 μL of perovskite precursor solution at 1000 rpm for 10 s, then spin coat at 5000 rpm for 40 s. Add 400 μL of chlorobenzene dropwise at the 20th second from the end of the total time for extraction. After extraction, place the solution on a heating stage and anneal at 100°C for 10 min to obtain the perovskite light-absorbing layer.

[0076] Step 5, with C is deposited sequentially on the surface of the perovskite light-absorbing layer at a certain speed. 60 With BCP and thicknesses of 20 nm and 7 nm respectively, an electron transport layer was obtained;

[0077] Step 6, with Cu is deposited on the surface of the electron transport layer at a speed of 100 nm to obtain a metal electrode layer.

[0078] Example 2

[0079] The preparation method of this embodiment is the same as that of Example 1, except that the concentration of hydroxyacetamide in the conductive polymer in step 2 is 10 mg / mL; and the concentration of hydroxyacetamide in the perovskite precursor solution in step 3 is 3 mg / mL.

[0080] Example 3

[0081] A wide-bandgap perovskite solar cell, the structure of which is shown in the figure below. Figure 2 As shown, it includes a conductive glass layer 1, a hole transport layer 2, a perovskite light-absorbing layer 3, an electron transport layer 4, and a metal electrode layer 5, which are stacked sequentially from bottom to top.

[0082] The specific fabrication method of the wide-bandgap perovskite solar cell in this embodiment is as follows:

[0083] Step 1: Clean and dry the 2cm×2cm ITO conductive glass layer;

[0084] Step 2: Prepare NiO with deionized water to a concentration of 5 mg / mL. xThe solution was prepared with methanol to a concentration of 0.3 mg / mL for Me-4PACz. First, NiO was added under an air atmosphere. x The solution was spin-coated on the ITO conductive glass layer at 2000 rpm for 30 s and annealed at 200℃ for 10 min to obtain the lower hole transport layer. Then, under a nitrogen atmosphere, the Me-4PACz solution was spin-coated on the lower hole transport layer at 3000 rpm for 30 s and annealed at 100℃ for 10 min to obtain the upper hole transport layer.

[0085] Step 3: Add FAI, CsI, PbI2, and SnBr2 to an organic solvent of N,N-dimethylformamide and dimethyl sulfoxide, then add hydroxyacetamide, and stir at 50°C for 60 min to obtain a perovskite precursor solution. In the perovskite precursor solution, the volume ratio of N,N-dimethylformamide to dimethyl sulfoxide is 4:1, the concentration of hydroxyacetamide is 1 mg / mL, the concentration of FAI is 1.12 mol / L, the concentration of CsI is 0.28 mol / L, the concentration of PbI2 is 0.56 mol / L, and the concentration of SnBr2 is 0.84 mol / L.

[0086] Step 4: Spin coat 50 μL of perovskite precursor solution at 1000 rpm for 10 s, then spin coat at 3000 rpm for 40 s. Add 100 μL of chlorobenzene dropwise at the 12th second from the end of the total time for extraction. After extraction, place the solution on a heating stage and anneal at 100°C for 10 min to obtain the perovskite light-absorbing layer.

[0087] Step 5, with C is deposited sequentially on the surface of the perovskite light-absorbing layer at a certain speed. 60 With BCP and thicknesses of 20 nm and 7 nm respectively, an electron transport layer was obtained;

[0088] Step 6, with Cu is deposited on the surface of the electron transport layer at a speed of 100 nm to obtain a metal electrode layer.

[0089] Example 4

[0090] A schematic diagram of an all-perovskite tandem solar cell is shown below. Figure 3 As shown, the structure includes, from bottom to top, a conductive glass layer 1, a first hole transport layer 6, a second hole transport layer 7, a wide bandgap perovskite light-absorbing layer 8, a first electron transport layer 9, a second electron transport layer 10, a first metal electrode layer 11, a third hole transport layer 12, a narrow bandgap perovskite light-absorbing layer 13, a third electron transport layer 14, a fourth electron transport layer 15, and a second metal electrode layer 16.

[0091] The fabrication method of the perovskite tandem solar cell in this embodiment is as follows:

[0092] Step 1: Clean and dry the 2cm×2cm ITO conductive glass layer;

[0093] Step 2: Prepare NiO with deionized water to a concentration of 5 mg / mL. x The solution was prepared with methanol to a concentration of 0.3 mg / mL for Me-4PACz. First, NiO was added under an air atmosphere. x The solution was spin-coated on the ITO conductive glass layer at 2000 rpm for 30 s and annealed at 200℃ for 10 min to obtain the first hole transport layer. Then, under a nitrogen atmosphere, the Me-4PACz solution was spin-coated on the first hole transport layer at 3000 rpm for 30 s and annealed at 100℃ for 10 min to obtain the second hole transport layer.

[0094] Step 3: Add FAI, CsI, PbI2, and SnBr2 to an organic solvent of N,N-dimethylformamide and dimethyl sulfoxide, then add hydroxyacetamide, and stir at 50°C for 60 min to obtain a perovskite precursor solution. In the perovskite precursor solution, the volume ratio of N,N-dimethylformamide to dimethyl sulfoxide is 4:1, the concentration of hydroxyacetamide is 1 mg / mL, the concentration of FAI is 1.12 mol / L, the concentration of CsI is 0.28 mol / L, the concentration of PbI2 is 0.56 mol / L, and the concentration of SnBr2 is 0.84 mol / L.

[0095] Step 4: Spin coat 50 μL of perovskite precursor solution at 1000 rpm for 10 s, then spin coat at 3000 rpm for 40 s. Add 100 μL of chlorobenzene dropwise at the 12th second from the end of the total time for extraction. After extraction, place the solution on a heating stage and anneal at 100 °C for 10 min to obtain a wide-bandgap perovskite light-absorbing layer.

[0096] Step 5: First, deposit C on the wide-bandgap perovskite light-absorbing layer. 60 A first electron transport layer with a thickness of 15 nm was obtained, and then SnO2 was atomically deposited to obtain a second electron transport layer with a thickness of 20 nm.

[0097] Step 6: Deposit Au on the second electron transport layer to obtain a first metal electrode layer with a thickness of 1 nm;

[0098] Step 7: Add hydroxyacetamide to PEDOT:PSS conductive polymer until the concentration of hydroxyacetamide in the conductive polymer reaches 5 mg / mL. Spin-coat 75 μL of conductive polymer onto the first metal electrode layer at a speed of 5000 rpm for 30 s. Anneal at 140 °C for 20 min to obtain the hole transport layer.

[0099] Step 8: Add FAI, MAI, SnI2, PbI2, and SnF2 to an organic solvent of N,N-dimethylformamide and dimethyl sulfoxide, then add hydroxyacetamide, and stir at 50°C for 60 min to obtain a perovskite precursor solution. In the perovskite precursor solution, the volume ratio of N,N-dimethylformamide to dimethyl sulfoxide is 3:1, the concentration of hydroxyacetamide is 1 mg / mL, the concentration of FAI is 1.1 mol / L, the concentration of MAI is 1.1 mol / L, the concentration of SnI2 is 1.1 mol / L, the concentration of PbI2 is 1.1 mol / L, and the concentration of SnF2 is 0.1 mol / L.

[0100] Step 9: Spin coat 50 μL of perovskite precursor solution at 1000 rpm for 10 s, then spin coat at 5000 rpm for 40 s. Add 400 μL of chlorobenzene dropwise at the 20th second from the end of the total time for extraction. After extraction, place the solution on a heating stage and anneal at 100 °C for 10 min to obtain a narrow bandgap perovskite light-absorbing layer.

[0101] Step 10, with C is deposited sequentially on the surface of the narrow bandgap perovskite light-absorbing layer at a speed of [speed not specified]. 60 BCP and a third electron transport layer with a thickness of 20 nm and a fourth electron transport layer with a thickness of 7 nm were obtained, respectively.

[0102] Step 6, with Cu was deposited on the surface of the fourth electron transport layer at a speed of 100 nm to obtain the second metal electrode layer.

[0103] Comparative Example 1

[0104] The preparation method of Comparative Example 1 is the same as that of Example 1, except that hydroxyacetamide is not added to the conductive polymer in step 2 and the perovskite precursor solution in step 3.

[0105] Hydroxyacetamide is composed of a carbonyl group (C=O) and an amino group (-NH2) covalently linked, with an additional hydroxyl group. The amide group can regulate the pH of the hole transport layer PEDOT:PSS, reducing PEDOT:PSS erosion of the perovskite bottom, minimizing defects at the perovskite buried interface, and promoting perovskite grain growth. Figures 4 to 6 As shown in the attached figures, the perovskite layer prepared in Comparative Example 1 has poor crystal orientation and uneven grain size, while the perovskite layer prepared in Example 1 has more penetrating grains and more distinct boundaries. Figure 5 As shown in the perovskite layer surface diagram, the perovskite grain size is similar, the film quality is improved, and thus the efficiency of perovskite solar cells is enhanced.

[0106] Because hydroxyacetamide is added to the precursor solutions of narrow-bandgap perovskite and wide-bandgap perovskite, the amide groups used in the perovskite absorber layer are oxidized to carboxylic acids, which to some extent reduces the Sn content in narrow-bandgap perovskite. 2+ The oxidation of hydroxyacetamide reduces thin-film defects and non-radiative recombination, enhancing carrier transport. Furthermore, hydroxyacetamide improves the energy level matching of perovskite, increasing thin-film quality and significantly improving the photoelectric conversion efficiency of single-junction perovskite solar cells. Figures 7 to 10 As shown in the accompanying figures, the average efficiency of the narrow bandgap perovskite solar cells prepared in Examples 1 and 2 is improved by more than 2% compared to Comparative Example 1. The highest efficiency of Examples 1 and 2 reaches 21.5%, while the highest efficiency of Comparative Example 1 is only 20.2%. The highest efficiency of the wide bandgap perovskite solar cell also reaches 17.4%. By connecting the optimized single-junction perovskite solar cells in series to form an all-perovskite tandem solar cell, the highest efficiency reaches 27.56%.

[0107] Because hydroxyacetamide can also improve the long-term stability of perovskite solar cells, according to Figure 11 It can be seen that the thin films of Examples 1 and 2 have fewer defects and higher perovskite crystal quality, thus exhibiting better long-term stability and maintaining 90% of their initial efficiency even after about 20 days.

[0108] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An amide-based additive, characterized in that: The molecular structure of the amide-based additive is shown in Formula I. In formula I, R is selected from -H, -CH2OH, Either -CH2Cl or -CH=CH2.

2. The application of the amide-based additive of claim 1 in the preparation of perovskite solar cells, wherein the perovskite solar cells include narrow bandgap perovskite solar cells, wide bandgap solar cells, and all-perovskite tandem solar cells.

3. The method for fabricating a narrow bandgap perovskite solar cell according to claim 2, characterized in that: Includes the following steps: (1) A conductive polymer containing amide additives is spin-coated onto a conductive glass layer and then annealed to obtain a hole transport layer. (2) Spin-coating a tin-lead perovskite precursor solution containing amide-based additives onto the hole transport layer and annealing it to obtain a perovskite light-absorbing layer. (3) First, C is deposited on the perovskite light-absorbing layer. 60 Alternatively, PCBM is used to obtain a lower electron transport layer with a thickness of 20nm, followed by the deposition of BCP or SnO2 to obtain an upper electron transport layer with a thickness of 7nm. (4) Metal is deposited on the upper electron transport layer to obtain a metal electrode layer.

4. The method for fabricating a narrow bandgap perovskite solar cell according to claim 3, characterized in that: In step (1), the conductive polymer in the conductive polymer containing amide additives is PEDOT:PSS; The concentration of the amide group additive in the conductive polymer containing the amide group additive is 5-10 mg / mL; In step (2), the tin-lead perovskite precursor solution containing amide-based additives is selected from FA. n MA 1-n Pb x Sn 1-x I3 precursor solution or FA n Cs 1-n Pb x Sn 1-x I3 precursor solution, the FA n MA 1-n Pb x Sn 1- x I3 precursor solution and FA n Cs 1-n Pb x Sn 1-x In the I3 precursor solution, n satisfies 0 ≤ n ≤ 1, and x satisfies 0 ≤ x ≤ 1; The concentration of the amide group additive in the tin-lead perovskite precursor solution containing the amide group additive is 1–3 mg / mL.

5. The method for fabricating a wide-bandgap perovskite solar cell according to claim 2, characterized in that: Includes the following steps: S1. Spin-coat the first liquid precursor solution onto the conductive glass layer, and perform a first annealing treatment to obtain the lower hole transport layer. Then spin-coat the second liquid precursor solution onto the lower hole transport layer, and perform a second annealing treatment to obtain the upper hole transport layer. S2, FA containing amide group additives n Cs 1-n Pb(I x Br 1-x )3. The precursor solution is spin-coated onto the hole transport layer and annealed to obtain a perovskite light-absorbing layer. S3. First, C is deposited on the perovskite light-absorbing layer. 60 Alternatively, PCBM is used to obtain a lower electron transport layer with a thickness of 20nm, followed by the deposition of BCP or SnO2 to obtain an upper electron transport layer with a thickness of 7nm. S4. Deposit metal onto the upper electron transport layer to obtain a metal electrode layer.

6. The method for fabricating a wide-bandgap perovskite solar cell according to claim 5, characterized in that: In step S1, the first liquid precursor solution comprises water and PTAA, PTPD, 2PACz, 4PACz, 6PACz, Meo-2PACz, Meo-4PACz, Meo-6PACz and NiO. X Any mixture of solutions; The second liquid precursor solution includes a mixed solution of methanol and any one of Me-2PACz, Me-4PACz and Me-6PACz; In step S2, the FA containing amide group additives n Cs 1-n Pb(I x Br 1-x )3 The concentration of amide additive in the precursor solution is 1-3 mg / mL.

7. The method for preparing an all-perovskite tandem solar cell according to claim 2, characterized in that: Includes the following steps: A. Spin-coat the first liquid precursor solution onto the conductive glass layer, perform a first annealing treatment to obtain the first hole transport layer, then spin-coat the second liquid precursor solution onto the first hole transport layer, perform a second annealing treatment to obtain the second hole transport layer. B. FA containing amide-based additives n Cs 1-n Pb(I x Br 1-x )3 The precursor solution was spin-coated onto the second hole transport layer and annealed to obtain a wide-bandgap perovskite light-absorbing layer. C. First, deposit C on the surface of the wide-bandgap perovskite light-absorbing layer. 60 Alternatively, PCBM is used to obtain a first electron transport layer with a thickness of 20 nm, followed by atomic deposition of SnO2 to obtain a second electron transport layer with a thickness of 7 nm. D. Deposit Au or IZO nanoparticles on the surface of the second electron transport layer to obtain the first metal electrode layer; E. Spin-coating a conductive polymer containing amide additives onto the first metal electrode layer and annealing it to obtain a third hole transport layer. F. Spin-coat the tin-lead perovskite precursor solution containing amide-based additives onto the third hole transport layer, and anneal it to obtain a narrow bandgap perovskite light-absorbing layer. G. First, deposit C on the narrow bandgap perovskite light-absorbing layer. 60 Alternatively, PCBM is used to obtain a third electron transport layer with a thickness of 20 nm, followed by the deposition of BCP or SnO2 to obtain a fourth electron transport layer with a thickness of 7 nm. H. Deposit metal onto the fourth electron transport layer to obtain a second metal electrode layer.

8. The method for preparing an all-perovskite tandem solar cell according to claim 7, characterized in that: In step A, the first liquid precursor solution comprises water and PTAA, PTPD, 2PACz, 4PACz, 6PACz, Meo-2PACz, Meo-4PACz, Meo-6PACz, and NiO. X Any mixture of solutions; The second liquid precursor solution includes a mixed solution of methanol and any one of Me-2PACz, Me-4PACz and Me-6PACz; In step B, the FA containing amide group additives n Cs 1-n Pb(I x Br 1-x )3 The concentration of amide additive in the precursor solution is 1-3 mg / mL.

9. The method for preparing an all-perovskite tandem solar cell according to claim 7, characterized in that: In step E, the conductive polymer in the conductive polymer containing amide additives is PEDOT:PSS; The concentration of the amide group additive in the conductive polymer containing the amide group additive is 5-10 mg / mL.

10. The method for preparing an all-perovskite tandem solar cell according to claim 7, characterized in that: In step F, the tin-lead perovskite precursor solution containing amide-based additives is selected from FA. n MA 1-n Pb x Sn 1-x I3 precursor solution or FA n Cs 1-n Pb x Sn 1-x I3 precursor solution, the FA n MA 1-n Pb x Sn 1-x I3 precursor solution and FA n Cs 1-n Pb x Sn 1-x In the I3 precursor solution, n satisfies 0 ≤ n ≤ 1, and x satisfies 0 ≤ x ≤ 1; The concentration of the amide group additive in the tin-lead perovskite precursor solution containing the amide group additive is 1–3 mg / mL.

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