A method for crystallization regulation of a perovskite / self-assembled monolayer co-deposition system for doctor-blade coating and a perovskite solar cell

Abstract

A kind of crystallization regulation method for doctor-blade perovskite / self-assembled monolayer co-deposition system and perovskite solar cell.The solar cell structure is sequentially from bottom to top as bottom substrate,transparent electrode,perovskite light absorption layer containing self-assembled monolayer,passivation layer,electron transport layer,buffer layer and metal electrode.The self-assembled monolayer is introduced into perovskite precursor solution,co-deposition film is formed by doctor-blade perovskite and self-assembled monolayer to replace traditional layered deposition method,so as to simplify the preparation process of battery and improve the adaptability of large-area perovskite solar cell preparation.On this basis,benzylurea is further added into perovskite precursor solution as crystallization regulation material,use the regulation effect of benzylurea on colloid structure and coordination environment in precursor solution,efficiently increase the size of colloid,delay perovskite crystal growth process,reduce perovskite film defect density,then significantly improve the photoelectric conversion efficiency of perovskite solar cell.

Description

Technical Field

[0001] This invention relates to the field of solar cell technology, specifically to a method for controlling the crystallization of perovskite / self-assembled monomolecules in a blade coating process and the perovskite solar cell prepared therefrom. Background Technology

[0002] In recent years, self-assembled single-molecule hole transport materials have been widely used in perovskite solar cells due to their advantages such as high optical transmittance, tunable energy level positions, and low-temperature processing. However, there are still challenges in applying self-assembled single molecules as hole transport layers to large-scale commercial production. The main reasons include: (1) In order to reduce series resistance and interface loss, the self-assembled single-molecule layer needs to be prepared to be extremely thin and uniformly distributed while maintaining a tight and ordered arrangement, which is difficult to achieve stably in large-area preparation; (2) The interface characteristics (such as wettability) between self-assembled single molecules and perovskite significantly affect the nucleation kinetics and crystal growth orientation of perovskite, which is crucial for obtaining high-quality large-area perovskite thin films; (3) The current mainstream spin-coating preparation method has low material utilization, limited scalability, and limited uniformity in large-area preparation.

[0003] To date, the performance of perovskite solar cells prepared by blade coating still lags behind that prepared by spin coating. The solvent evaporation, perovskite nucleation, and crystallization processes are more complex. Therefore, achieving co-deposition of perovskite and self-assembled monomolecules into a film, and systematically controlling the crystallization growth process of the perovskite film, is crucial for the fabrication of high-performance, large-area perovskite solar cells. Summary of the Invention

[0004] To address the problems of existing technologies, this invention combines a perovskite / self-assembled monomolecule co-deposition system with a scalable preparation method—the blade coating method—to promote the commercial application of self-assembled monomolecules in perovskite solar cells. Based on the above technical concept, this invention adds benzylurea to a perovskite precursor solution containing self-assembled monomolecules to regulate the formation process of the blade-coated perovskite film and ultimately reduce film defects, thereby effectively improving the performance of perovskite solar cells.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] A perovskite solar cell, the structure of which, from bottom to top, includes a bottom substrate, a transparent electrode, a perovskite light-absorbing layer containing self-assembled monomolecules, a passivation layer, an electron transport layer, a buffer layer, and a metal electrode.

[0007] The perovskite precursor solution of the perovskite light-absorbing layer contains a bulk dopant, benzylurea, whose structural formula is shown in Formula 1:

[0008]

[0009] Formula 1

[0010] The molecular formula of the bulk dopant is C8H. 10 N2O.

[0011] Preferably, the perovskite solar cell is a PIN-type perovskite solar cell;

[0012] The perovskite solar cell mentioned is a single-junction perovskite solar cell;

[0013] The perovskite solar cell has a conventional bandgap of ~1.50 eV or a wide bandgap of 1.60 eV or more.

[0014] Preferably, the perovskite material is an organic-inorganic hybrid perovskite material.

[0015] Preferably, the underlying substrate includes one or more of transparent glass, flexible PET substrate, and flexible PEN substrate.

[0016] Preferably, the transparent electrode can be one or more of the following: FTO transparent electrode, ITO transparent electrode, IZO transparent electrode, IZrO transparent electrode, AZO transparent electrode, and oxide-metal-oxide multilayer composite transparent electrode.

[0017] Preferably, the self-assembled monomer is one or more of (2-(9H-carbazole-9-yl)ethyl)phosphonic acid (2PACz), (2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl)phosphonic acid (MeO-2PACz), (4-(3,6-dimethyl-9H-carbazole-9-yl)butyl)(Me-4PACz), and (4-(7H-dibenzo[c,g]carbazole-7-yl)butyl)phosphonic acid (4PADCB).

[0018] Preferably, the passivation layer is one or more of 1,3-diaminopropane dihydroiodate (PDAI2), piperazine dihydroiodate (PI), phenylethyl iodide (PEAI), and phenylethyl iodide (PEABr).

[0019] Preferably, the electron transport layer is SnO2, TiO2, ZnO, PCBM, or C. 60 One or more of other electron transport materials such as fullerene derivatives.

[0020] Preferably, the buffer layer is one or more of BCP, PEI, ZnO, SnO2, Al2O3, SiO2, LiF or MgF2.

[0021] Preferably, the metal electrode material is one or more of Ag, Au, Cu, and Al, and the thickness is 80~120 nm.

[0022] This invention provides a method for fabricating the perovskite solar cell described above, including a transparent electrode pretreatment step; a step of fabricating a perovskite light-absorbing layer on the surface of the transparent electrode; a step of fabricating a passivation layer on the surface of the perovskite light-absorbing layer; a step of spin-coating an electron transport layer on the surface of the passivation layer; a step of spin-coating a buffer layer on the surface of the electron transport layer; and a step of fabricating a metal electrode on the surface of the buffer layer.

[0023] The perovskite light-absorbing layer is prepared by a blade coating method, including:

[0024] Benzylurea (0.5~1.5 mg) was added to a solution containing a single perovskite precursor to obtain a mixed solution; the mixed solution was coated onto the surface of a transparent electrode and annealed; the coating speed was 5~15 mm / s, the nitrogen purging speed was 5~15 mm / s, and the coating time was 10~30 s.

[0025] The annealing temperature is 100~150℃, and the annealing time is 10~60 min.

[0026] Advantages and positive effects of the present invention:

[0027] 1. Perovskite / Self-assembled Monomer Co-deposition System: Self-assembled monomers are directly incorporated into the perovskite precursor solution to achieve one-step co-deposition of perovskite and self-assembled monomers. This system is combined with the blade coating method to promote the large-area commercial application of self-assembled monomers in perovskite solar cells.

[0028] 2. Crystallization process control: By adding benzylurea, the size of the precursor colloidal particles is controlled, the nucleation density during the nitrogen purging stage is suppressed, and the crystallization kinetics are slowed down, ultimately obtaining large-sized perovskite grains and significantly reducing grain boundary defects.

[0029] 3. Defect passivation and stabilization: The C=O in benzylurea can form a Pb-O coordination bond with uncoordinated Pb²⁺, and -NH2 can interact with formamidinium cations (FA⁺) through NH···F hydrogen bonds, thereby passivating bulk defects and improving the stability of perovskite.

[0030] 4. The perovskite solar cell preparation method of the present invention is a blade coating method, which is suitable for the preparation of large-area thin films. This provides a technical route for the preparation of high-quality large-area perovskite thin films and the improvement of cell efficiency. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of the perovskite solar cell provided by the present invention.

[0032] Figure 2This is a schematic diagram of the perovskite / crystalline silicon tandem solar cell structure of the present invention;

[0033] Figure 3 The JV curve of the perovskite solar cell described in Example 1 of this invention;

[0034] Figure 4 The JV curve of the perovskite solar cell described in Comparative Example 1 of this invention;

[0035] Figure 5 The graph shows the open-circuit voltage, short-circuit current density, fill factor, and power conversion efficiency of the perovskite solar cells described in Example 1 and Comparative Example 1.

[0036] Figure 6 The XRD patterns of the perovskite light-absorbing layers corresponding to Example 1 and Comparative Example 1 are shown below.

[0037] Figure 7 SEM images of the perovskite light-absorbing layers corresponding to Example 1 and Comparative Example 1; Detailed Implementation

[0038] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments, nor do they limit the content and scope of protection of the present invention. Where specific experimental steps or conditions are not specified in the embodiments, they can be performed according to the conventional experimental steps or conditions described in the literature in the art. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0039] The perovskite solar cell of this invention is an accessory Figure 1 The single-junction perovskite solar cell shown may be an attached... Figure 2 The perovskite / crystalline silicon tandem solar cell shown is described. The perovskite solar cell of this invention has a conventional bandgap of ~1.50 eV or a wide bandgap of 1.60 eV or more.

[0040] Example 1

[0041] The PIN-type perovskite solar cell provided in this embodiment has a bandgap of approximately 1.68 eV, and its structure is as follows: Figure 1 As shown, from bottom to top, it includes: transparent glass, ITO, perovskite light absorption layer (containing self-assembled monomolecules), PDAI2 (passivation layer), PCBM (electron transport layer), BCP (buffer layer), and silver electrode.

[0042] The method for fabricating a PIN-type perovskite solar cell in this embodiment includes the following steps:

[0043] Step 1, Transparent Electrode Pretreatment: Clean the ITO conductive glass in sequence with detergent, deionized water, and isopropanol, then dry it with nitrogen and treat it with ultraviolet ozone.

[0044] Step 2, Preparation of perovskite light-absorbing layer: (1) Preparation of 1.5 M Cs containing 4 PADCB in DMF / NMP (9 / 1:v / v) co-solvent. x FA 1-x Pb(I y Br 1-y (2) Add 1 mg of bulk dopant benzylurea to the perovskite precursor solution; (3) Coat the obtained perovskite precursor solution onto the ITO surface with a coating speed of 9 mm / s, a nitrogen purging speed of 5 mm / s, and a coating time of 15 s; (4) Anneal the obtained wet film at 130 ℃ for 30 min to obtain the perovskite light absorption layer.

[0045] Step 3, prepare the passivation layer: spin-coat PDAI2 on the surface of the perovskite light absorption layer as a passivation layer.

[0046] Step 4, prepare the electron transport layer: spin-coat PCBM on the surface of the passivation layer as the electron transport layer.

[0047] Step 5, Prepare the buffer layer: Spin-coat BCP as a buffer layer on the surface of the electron transport layer.

[0048] Step 6, Prepare the metal electrode: Prepare a silver metal electrode on the surface of the buffer layer.

[0049] Step 7, Photovoltaic Performance Testing: The effective area of ​​the perovskite solar cell device prepared by the above method is 0.12 cm². 2 At 100 mW / cm 2 Measurements were taken under illumination (AM 1.5G), with a scan range from 1.3 V to 0 V and a scan step size of 0.02 V.

[0050] The JV characteristic curves of the obtained perovskite solar cells are as follows: Figure 3 As shown, by Figure 3 It is known that the open-circuit voltage of the perovskite solar cell is 1.22 V, the fill factor is 84.55%, and the short-circuit current density is 21.74 mA / cm². 2 The power conversion efficiency is 22.39%.

[0051] Example 2

[0052] Unlike Example 1, the transparent electrode was selected as an IZO transparent electrode.

[0053] Example 3

[0054] Unlike Examples 1-2, the electron transport layer is C. 60 .

[0055] Example 4

[0056] Unlike Examples 1-3, the metal electrode material is Cu.

[0057] Comparative Example 1

[0058] The comparative example provides a PIN-type perovskite solar cell with a band gap of approximately 1.68 eV, which, from bottom to top, includes: transparent glass, ITO, a perovskite light-absorbing layer (containing self-assembled monomolecules), PDAI2 (passivation layer), PCBM (electron transport layer), BCP (buffer layer), and a silver electrode.

[0059] To further compare the technical solution of the present invention and its beneficial effects, the perovskite solar cell prepared was prepared in a manner that was largely the same as in Example 1, except that no bulk dopant was added in step 2 of this comparative example.

[0060] The JV characteristic curves of the obtained perovskite solar cells are as follows: Figure 4 As shown, the perovskite solar cell has an open-circuit voltage of 1.19 V, a fill factor of 80.92%, and a short-circuit current density of 20.57 mA / cm². 2 The power conversion efficiency is 19.85%. Figure 5 The open-circuit voltage, short-circuit current density, fill factor, and power conversion efficiency of the perovskite solar cells of Example 1 and Comparative Example 1 are shown in the following graphs. Figure 6 The XRD patterns of the perovskite light-absorbing layers corresponding to Example 1 and Comparative Example 1 are shown. Figure 7 SEM images of the perovskite light-absorbing layers corresponding to Example 1 and Comparative Example 1;

[0061] In summary, this invention utilizes a one-step coating method to prepare perovskite / self-assembled monomolecule co-deposition and introduces the bulk dopant benzylurea. This not only optimizes the nucleation and crystallization process of perovskite but also results in a perovskite film with fewer defects, significantly improving carrier extraction and transport. Perovskite solar cells prepared using this method ultimately achieve higher open-circuit voltage and power conversion efficiency. The overall combination of "benzylurea bulk doping + inverse structure + SAM layer" in this invention brings outstanding technical effects. This method is simple to operate, easy to implement, and has good reproducibility, showing promising application prospects in the fabrication of large-area perovskite solar cells and modules.

[0062] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A perovskite solar cell, characterized in that, The solar cell structure, from bottom to top, includes a bottom substrate, a transparent electrode, a perovskite light-absorbing layer containing self-assembled single molecules, a passivation layer, an electron transport layer, a buffer layer, and a metal electrode; wherein the perovskite precursor solution of the perovskite light-absorbing layer contains the bulk dopant benzylurea, the structural formula of which is shown in Formula 1: Formula 1 Formula 1 has the molecular formula C8H 10 N2O; The self-assembled monomolecule is one or more of the following: (2-(9H-carbazole-9-yl)ethyl)phosphonic acid (2PACz), (2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl)phosphonic acid (MeO-2PACz), (4-(3,6-dimethyl-9H-carbazole-9-yl)butyl) (Me-4PACz), and (4-(7H-dibenzo[c,g]carbazole-7-yl)butyl)phosphonic acid (4PADCB).

2. The perovskite solar cell as described in claim 1, characterized in that, The perovskite solar cell is a PIN-type perovskite solar cell. The perovskite solar cell is a single-junction perovskite solar cell or a perovskite / crystalline silicon tandem solar cell. The perovskite solar cell has a conventional bandgap of ~1.50 eV or a wide bandgap of 1.60 eV or more. The perovskite material described is an organic-inorganic hybrid perovskite.

3. The perovskite solar cell as described in claim 1, characterized in that, The underlying substrate includes one or more of transparent glass, flexible PET substrate, and flexible PEN substrate.

4. The perovskite solar cell as described in claim 1, characterized in that, The transparent electrode is one or more of the following: FTO transparent electrode, ITO transparent electrode, IZO transparent electrode, IZrO transparent electrode, AZO transparent electrode, and oxide-metal-oxide multilayer composite transparent electrode.

5. The perovskite solar cell as described in claim 1, characterized in that, The passivation layer is one or more of 1,3-diaminopropane dihydroiodate, piperazine dihydroiodate, phenylethyl iodide, and phenylethyl bromide.

6. The perovskite solar cell as described in claim 1, characterized in that, The electron transport layer is SnO2, TiO2, ZnO, PCBM, or C. 60 One or more of fullerene derivative electron transport materials; The buffer layer is one or more of BCP, PEI, ZnO, SnO2, Al2O3, SiO2, LiF or MgF2.

7. The perovskite solar cell as described in claim 1, characterized in that, The metal electrode material is one or more of Ag, Au, Cu, and Al, and has a thickness of 80~120 nm.

8. A method for preparing a perovskite solar cell according to any one of claims 1-7, characterized in that, This includes the step of pre-treating the transparent electrode; The step includes preparing a perovskite light-absorbing layer on the surface of a transparent electrode; This includes the step of preparing a passivation layer on the surface of the perovskite light-absorbing layer; This includes the step of spin-coating an electron transport layer onto the surface of a passivation layer; This includes the step of spin-coating a buffer layer onto the surface of the electron transport layer; This includes the step of fabricating a metal electrode on the surface of the buffer layer; The perovskite light-absorbing layer is prepared by a blade coating method, including: Benzylurea was added to a perovskite precursor solution containing self-assembled monomolecules to obtain a mixed solution; the mixed solution was coated onto the surface of a transparent electrode and annealed; the coating speed was 5~15 mm / s, the nitrogen purging speed was 5~15 mm / s, and the coating time was 10~30 s. The annealing temperature is 100~150℃, and the annealing time is 10~60 min.

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