Double-heterostructure 2D perovskite solar cell applied to indoor photovoltaic and preparation method of double-heterostructure 2D perovskite solar cell

Abstract

The invention relates to a double-heterostructure 2D perovskite solar cell applied to indoor photovoltaics and a preparation method thereof, the solar cell sequentially comprises an ITO substrate, a MeO-2PACz hole transport layer, a 2D perovskite double-heterostructure absorption layer, a PC61BM electron transport layer and an Ag electrode along the direction of incident light, and the 2D perovskite double-heterostructure is composed of DJ type and RP type perovskite. And the interface of the electron transport layer is also modified with a BCP layer. According to the preparation method disclosed by the invention, a layer of novel RP type 2D perovskite structure can be formed on the surface of the original DJ type 2D perovskite layer, so that the interface defects of the 2D perovskite are effectively reduced, and the photovoltaic performance of the 2D perovskite device under the indoor light condition is further improved.

Description

Technical Field

[0001] The present invention belongs to the field of thin-film solar cells, and in particular relates to a double heterostructure 2D perovskite solar cell applied to indoor photovoltaics and a preparation method thereof. Background Art

[0002] With the development of IoT technology and the popularity of smart home systems, the market demand for small, low-power electronic devices is growing. The power consumption of some chips has been reduced to the microwatt level, which makes it possible to use customized indoor photovoltaic cells to obtain electricity from indoor light energy, thereby powering IoT devices. Since 2021, a variety of materials including silicon, III-V semiconductors, organic materials and perovskites have been widely studied for harvesting energy from indoor artificial light sources. Among them, perovskite materials have emerged among many materials with their adjustable bandgap width, high defect tolerance and low cost. As of 2024, the highest certified indoor photovoltaic efficiency has reached 44.72%, showing its great potential in this field. 2D perovskite is considered to be one of the most promising materials for indoor photovoltaic applications due to its adjustable bandgap, high absorption coefficient, vertical crystallization characteristics and enhanced stability.

[0003] Despite the great potential of 2D perovskites in indoor photovoltaics, research on the indoor photovoltaic performance of 2D perovskite solar cells is still limited. Currently, the preparation of high-quality 2D perovskite films is the key to improving the indoor photovoltaic performance of devices, and uniform crystallization and optimal orientation are essential for maximizing conversion efficiency. However, it is still a challenge to control the relevant parameters during the deposition of perovskite films, which can lead to various defects in 2D perovskites. These defects act as non-radiative recombination centers, thus affecting the overall performance of the device. Summary of the invention

[0004] The purpose of the present invention is to provide a double heterostructure 2D perovskite solar cell for indoor photovoltaics and a preparation method thereof. The preparation method of the present invention can form a layer of novel RP-type 2D perovskite structure on the surface of the original DJ-type 2D perovskite layer, effectively reducing the interface defects of the 2D perovskite, thereby improving the photovoltaic performance of the 2D perovskite device under indoor light conditions.

[0005] To achieve the above object, the technical solution adopted by the present invention is: A double heterostructure 2D perovskite solar cell for indoor photovoltaics and a preparation method thereof, wherein the solar cell comprises an ITO substrate, a MeO-2PACz hole transport layer, a 2D perovskite double heterostructure absorption layer, a PC 61 BM electron transport layer and Ag electrode. The 2D perovskite double heterostructure consists of DJ-type and RP-type perovskites.

[0006] Furthermore, the ITO glass substrate has an ITO thickness of 150 to 200 nm.

[0007] Furthermore, the thickness of the MeO-2PACz layer is 20 to 30 nm.

[0008] Furthermore, the DJ-type perovskite layer is EDA (FA) 4 Pb 5 I 16 Thin film, thickness 350 ~ 400 nm; RP type perovskite layer BA 2 FAP 2 I 7 Thin film, thickness is 20 ~ 30 nm.

[0009] Furthermore, the PC 61 The thickness of the BM electron transport layer is 20-30 nm; in addition, a BCP layer is also modified at the interface of the electron transport layer, and the thickness of the BCP layer is 7 nm.

[0010] Furthermore, the Ag electrode has a thickness of 100 nm.

[0011] The present invention also provides a method for preparing the above-mentioned double heterostructure 2D perovskite solar cell, comprising the following steps: (1) Clean the substrate and then blow dry it with nitrogen to obtain a clean ITO substrate; (2) Preparation of hole transport layer: using solution spin coating technology, MeO-2PACz is dissolved in isopropanol and spin coated on the surface of the substrate to obtain the hole transport layer; (3) Preparation of 2D perovskite double heterostructure: A DJ-type perovskite layer was prepared by solution spin coating technology; then, butylamine hydroiodide BAI was used to perform interface treatment on the DJ-type perovskite surface to obtain a 2D perovskite double heterostructure with good crystallinity; (4) Preparation of electron transport layer: PC 61 BM was dissolved in chlorobenzene and spin-coated on the treated perovskite surface to obtain the PC 61 BM electron transport layer; PC is then spin-coated with BCP 61 Interface modification of BM; (5) Deposit Ag electrode on the electron transport layer using vacuum evaporation technology.

[0012] Furthermore, when the double heterostructure 2D perovskite solar cell is specifically applied to indoor photovoltaic devices, the indoor lighting conditions are 3000 K color temperature LED lighting, the illumination is 1000 lux, and the incident light power is 349 μW cm-2 .

[0013] Compared with the prior art, the present invention has the following beneficial effects: The present invention can effectively reduce the defect density at the interface by introducing long-chain BA ions, thereby reducing the probability of non-radiative recombination and improving the photovoltaic performance of the device; and the introduction of longer-chain BA ions to form a 2D perovskite with a low n value improves the stability of the material, especially enhances its ability to resist moisture erosion, which is conducive to extending the service life of the device. In addition, the preparation method provided by the present invention is simple and easy to implement, which is conducive to the realization of industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the device structure of a double heterojunction 2D perovskite solar cell according to an embodiment of the present invention.

[0015] Figure 2 These are SEM images of the surfaces of the original DJ-type 2D perovskite (left) and the DJ / RP double heterojunction perovskite (right) in the embodiments of the present invention.

[0016] Figure 3 It is EDA (FA) in the embodiment of the present invention 4 Pb 5 I 16 Whether to use BAI interface modification (a) and BA 2 FAP 2 I 7 (b) XRD pattern of.

[0017] Figure 4 It is the spectrum of the indoor light source with an illumination of 1000 lux and the corresponding integrated light source power in the embodiment of the present invention.

[0018] Figure 5 2 is the JV curve of the original DJ-type 2D perovskite and the DJ / RP double heterojunction perovskite in the embodiment of the present invention.

[0019] Figure 6 This is a device stability test of the DJ-type 2D perovskite and DJ / RP double heterojunction perovskite solar cells in the embodiments of the present invention under the conditions of 25°C and 30% RH. DETAILED DESCRIPTION

[0020] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0021] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0022] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0023] like Figure 1 As shown, this embodiment provides a double heterostructure 2D perovskite solar cell, which includes an ITO substrate, a MeO-2PACz hole transport layer, a 2D perovskite double heterostructure absorption layer, a PC 61 BM electron transport layer and Ag electrode.

[0024] In this embodiment, the thickness of the ITO substrate is 200 nm. The thickness of the MeO-2PACz layer is 20 nm. The 2D perovskite layer EDA (FA) 4 Pb 5 I 16 The thickness of the new RP perovskite BA is 350 nm. 2 FAP 2 I 7 The thickness of the layer is 20 nm. 61 The thickness of the BM electron transport layer is 25 nm. The thickness of the BCP layer is 7 nm. The thickness of the Ag electrode is 100 nm.

[0025] In this embodiment, the preparation process of the double heterostructure 2D perovskite solar cell is as follows: (1) Processing substrate First, the ITO glass substrate was pretreated by ultrasonic cleaning with detergent, deionized water, acetone, and anhydrous ethanol for 20 minutes, and then the surface of the ITO glass substrate was blown dry with nitrogen gas. The thickness of ITO is 200 nm and the area is 1.5×1.5 cm 2 , square resistance is 15 Ω sq -1 Then, the surface of the ITO substrate was treated with UV-irradiation and ozone for 30 minutes.

[0026] (2) Preparation of hole transport layer The MeO-2PACz hole transport layer was prepared on the treated ITO substrate by solution spin coating: MeO-2PACz was dissolved in isopropanol at a ratio of 0.5 mg / mL, spin coated at 4000 rpm for 30 seconds, and then annealed at 100°C for 10 minutes to complete the preparation of the hole transport layer.

[0027] (3) Preparation of perovskite absorber layer The perovskite absorber layer was prepared by solution spin coating. First, the DJ structure perovskite precursor solution EDA (FA) with n=5 was prepared according to the molar ratio of 1:4:5. 4 Pb 5 I 16 The raw materials used are ethylenediamine iodide (EDADI), formamidine hydroiodide (FAI) and PbI 2 The molar ratio is 1:4:5, and the solvent is a mixture of DMF and DMSO (volume ratio 4:1), where Pb 2+ The concentration of methyl ammonium chloride (MACl) was 1.0 mol / L. Subsequently, 15 mol% of the total amount of all A-site cations was added to the precursor solution to control the growth of the perovskite film. The solution was stirred at 70 °C for 2 hours and then cooled to room temperature for use.

[0028] During the spin coating of the 2D perovskite film, the substrate was first spun at 1000 rpm for 3 seconds, then the speed was increased to 5000 rpm for 30 seconds. 150 μl of chlorobenzene was added to the center of the film 15 seconds before the end of the spin coating. Immediately after the spin coating, the substrate was transferred to a hot plate and annealed at 110 °C for 20 minutes.

[0029] For the surface treatment of 2D perovskite, BAI solution (5 mmol / L dissolved in isopropanol) was dynamically spin-coated on the surface of 2D perovskite and annealed to obtain a new RP structure of 2D perovskite BA. 2 FAP 2 I 7 The BAI solution was spin-coated at a speed of 5000 rpm for 30 seconds, and the annealing temperature was 110° C. for 10 minutes.

[0030] like Figure 2 As shown, the BAI-modified 2D perovskite surface exhibits obvious changes in perovskite characteristics, indicating that the BA cations successfully modified the perovskite surface, and this morphological change can be attributed to the formation of a dense layer of the RP perovskite structure.

[0031] Figure 3 for EDA(FA) 4 Pb 5 I 16 Whether to use BAI interface modification (a) and BA 2 FAP 2 I 7 (b) XRD pattern. The BAI-modified 2D perovskite shows new diffraction peaks at 2θ = 9.1° and 21.3°, corresponding to the BA-based 2 FAP 2 I7 The specific crystal planes (040) and (280) of the perovskite film prove that a new BA with RP phase is formed on the original DJ-type perovskite film. 2 FAP 2 I 7 structure.

[0032] (4) Preparation of electron transport layer Preparation of PC on perovskite surface by solution spin coating 61 BM electron transport layer: PC 61 BM was dissolved in chlorobenzene at a ratio of 20 mg / mL, spin-coated at 4000 rpm for 30 seconds, and then annealed at 70°C for 10 minutes to complete the preparation of the electron transport layer. Next, 2,9-dimethyl-4,7-biphenyl-1,10-phenanthroline (BCP) was dissolved in isopropanol at a ratio of 0.5 mg / mL and spin-coated at 5000 rpm for 30 seconds to prepare the PC. 61 Interface modification of BM layer.

[0033] (5) Preparation of Ag electrode Combined with the electrode mask, the Ag electrode was prepared on the window layer using vacuum evaporation technology. The process parameters were set to: vacuum degree less than 1×10 -4 Pa, the evaporation rate is 1 Å / s, and the deposition thickness is 100 nm.

[0034] Through the above steps, the preparation of the double heterostructure 2D perovskite solar cell is completed. In this embodiment, a DJ-type 2D perovskite device with a perovskite surface treatment without BAI solution is used for comparison test, and the other preparation steps are the same.

[0035] Figure 4 is the spectrum of the indoor light source with an illumination of 1000 lux in this embodiment and the corresponding integrated light source power. This embodiment uses LED lighting with a color temperature of 3000K and an illumination of 1000 lux. According to the measurement results, the spectral integrated intensity of the LED lighting is equivalent to 349 μW cm -2 The incident power of the light source.

[0036] like Figure 5 As shown, the test uses LED indoor lighting (3000 K, @1000 lux) to evaluate the photovoltaic performance of the device. A high-precision spectrometer (Hesenda HPC350) equipped with an incident window plane detector (cosine collector) is used to measure the emission spectrum and power intensity of the LED, and the detector is ensured to be at the same level and direction as the device to accurately calibrate the light intensity. The JV curve of the solar cell is measured using a Keithley 2400 source meter, and the effective illumination area is 0.059cm 2The JV curve data were collected at a scan rate of 50 mV / s during the forward scan from -0.05 to 1.2 V and the reverse scan from 1.2 to -0.05 V. The open circuit voltage of the original 2D perovskite device (comparison test) in this example is 890 mV and the short circuit current is 0.126 mA cm -2 , the fill factor is 73.7%, and the photoelectric conversion efficiency is 23.88%. In contrast, the open circuit voltage of the 2D perovskite device with RP-type structure is increased to 936 mV, and the short circuit current is increased to 0.140 mA cm -2 , the filling factor reaches 81.0%, and the photoelectric conversion efficiency is improved to 30.30%. Compared with the original DJ-type 2D perovskite device, the DJ / RP double heterojunction perovskite device of the present invention has achieved a significant improvement in indoor photovoltaic performance.

[0037] Figure 6 The stability of DJ-type 2D perovskite and DJ / RP double heterojunction perovskite solar cells was tested. Under ambient conditions (25°C and 30% RH), the 2D-DJ device retained only 82% of its initial efficiency after about 1800 hours, while the 2D-DJ / RP device still retained 97% of its initial efficiency. The excellent humidity stability of the 2D-DJ / RP device is attributed to the introduction of a low-n RP-type perovskite layer to enhance the stability of the perovskite surface structure, thereby inhibiting moisture erosion.

[0038] The above is only a preferred embodiment of the present invention, and does not limit the present invention in other forms. Any technician familiar with the profession may use the above disclosed technical content to change or modify it into an equivalent embodiment with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the technical solution of the present invention still belongs to the protection scope of the technical solution of the present invention.

Claims

1. A double heterostructure 2D perovskite solar cell for indoor photovoltaic applications, characterized in that: The solar cell includes an ITO substrate, a MeO-2PACz hole transport layer, a 2D perovskite double heterostructure absorption layer, a PC 61 BM electron transport layer and Ag electrode; the 2D perovskite double heterostructure is composed of DJ-type and RP-type perovskites.

2. A double heterostructure 2D perovskite solar cell for indoor photovoltaic applications according to claim 1, characterized in that: The indoor lighting conditions are 3000 K color temperature LED lighting, 1000 lux illumination, and 349 μW cm incident light power. -2 .

3. A double heterostructure 2D perovskite solar cell for indoor photovoltaic applications according to claim 1, characterized in that: The ITO thickness is 150 ~ 200 nm.

4. The double heterostructure 2D perovskite solar cell for indoor photovoltaic application according to claim 1, characterized in that: The thickness of the MeO-2PACz hole transport layer is 20 to 30 nm.

5. The double heterostructure 2D perovskite solar cell for indoor photovoltaic application according to claim 1, characterized in that: DJ-type perovskite layer is EDA(FA)4Pb5I 16 The film has a thickness of 350 ~ 400 nm; the RP-type perovskite layer is a BA2FAPb2I7 film with a thickness of 20 ~ 30 nm.

6. A double heterostructure 2D perovskite solar cell for indoor photovoltaic applications according to claim 1, characterized in that: The PC 61 The thickness of the BM electron transport layer is 20-30 nm.

7. A double heterostructure 2D perovskite solar cell for indoor photovoltaic applications according to claim 6, characterized in that: A BCP layer is also modified at the interface of the electron transport layer, and the thickness of the BCP layer is 7 nm.

8. The double heterostructure 2D perovskite solar cell for indoor photovoltaic application according to claim 1, characterized in that: The thickness of the Ag electrode is 100 nm.

9. A method for preparing a double heterostructure 2D perovskite solar cell for indoor photovoltaic applications according to any one of claims 1 to 8, characterized in that: The following steps are involved: (1) Clean the substrate and then blow dry it with nitrogen to obtain a clean ITO substrate; (2) Preparation of hole transport layer: MeO-2PACz was dissolved in isopropanol by solution spin coating technology and then spin coated on the substrate surface to obtain a hole transport layer; (3) Preparation of 2D perovskite double heterostructure: A DJ-type perovskite layer was prepared by solution spin coating technology; then, butylamine hydroiodide BAI was used to perform interface treatment on the DJ-type perovskite surface to obtain a 2D perovskite double heterostructure with good crystallinity; (4) Preparation of electron transport layer: PC 61 BM was dissolved in chlorobenzene and spin-coated on the surface of the absorption layer to obtain the PC 61 BM electron transport layer; then PC by BCP spin coating 61 Interface modification of BM; (5) Deposit Ag electrode on the electron transport layer using vacuum evaporation technology.

10. The method according to claim 9, characterized in that Step (5) The process parameters of the vacuum evaporation process are set to: vacuum degree is less than 1×10 -4 Pa, and the evaporation rate is 1 Å / s.

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