Perovskite solar cell based on composite interface modification engineering and preparation method thereof

Abstract

The application discloses a perovskite battery based on a composite interface modification engineering and a preparation method, relates to the technical field of perovskite batteries, and the perovskite battery comprises, from bottom to top, a conductive glass substrate, an electron transport layer, a first interface modification layer, a second interface modification layer, a perovskite layer, a hole transport layer and a metal electrode; the first interface modification layer is made of MgF2, and the second interface modification layer is made of MgO. The application constructs a composite interface modification layer based on the first interface modification layer and the second interface modification layer between the electron transport layer and the perovskite layer, effectively reduces interface recombination between the perovskite layer and the electron transport layer, reduces energy loss, improves charge extraction efficiency, provides an excellent barrier, blocks the erosion of moisture and environmental factors on the perovskite layer, and thus prolongs the service life of the battery.

Description

Technical Field

[0001] This application relates to the field of perovskite battery technology, and in particular to perovskite batteries based on composite interface modification engineering and their preparation methods. Background Technology

[0002] Perovskite solar cells have attracted much attention in recent years due to their excellent photoelectric conversion efficiency, tunable bandgap, and low fabrication cost. In traditional perovskite solar cells, oxygen vacancies and Ti vacancies exist at the interface between the perovskite layer and the electron transport layer. 3+ Defects at the interface make the battery prone to carrier recombination. This recombination not only reduces photoelectric conversion efficiency but also leads to decreased battery stability. Due to carrier recombination at the interface, energy loss significantly impacts the overall battery performance. Therefore, it is urgent to find effective methods to reduce interface recombination and improve charge extraction efficiency.

[0003] In the prior art, Chinese patent CN116133442A discloses a perovskite solar cell based on an organic molecule-modified lithium salt-doped hole transport layer. This method involves directly introducing organic molecules containing at least two electron-donating groups into the lithium salt-doped hole transport layer and spin-coating them onto the perovskite film surface using a one-step deposition method. By strictly controlling the amount of organic molecules added, the spin-coating speed, and the spin-coating time in the lithium salt-doped hole transport layer, the overall modification and optimization of the perovskite solar cell device is achieved. This results in a dual effect of reducing film defects and improving the water stability of the lithium salt-doped hole transport layer, thereby enhancing the photoelectric conversion efficiency and stability of the perovskite solar cell.

[0004] However, the aforementioned prior art does not consider the interfacial recombination problem between the perovskite layer and the electron transport layer, resulting in poor charge extraction efficiency. In addition, the aforementioned prior art also does not consider the erosion of the perovskite layer by moisture and environmental factors, resulting in a short battery life. Summary of the Invention

[0005] This application provides a perovskite solar cell based on composite interface modification engineering and its preparation method, in order to solve the problems of poor charge extraction efficiency and short battery life in existing perovskite solar cell technologies.

[0006] On the one hand, this application provides a perovskite solar cell based on composite interface modification engineering, comprising: from bottom to top, a conductive glass substrate, an electron transport layer, a first interface modification layer, a second interface modification layer, a perovskite layer, a hole transport layer, and a metal electrode.

[0007] The first interface modification layer uses MgF2, and the second interface modification layer uses MgO.

[0008] In one possible implementation, the electron transport layer is made of TiO2.

[0009] In one possible implementation, the electron transport layer, the first interface modification layer, and the second interface modification layer are all prepared by electron beam evaporation.

[0010] In one possible implementation, the perovskite layer is achieved by spin-coating CsPbI. 3-x Br x The perovskite solution was prepared.

[0011] In one possible implementation, the hole transport layer is prepared by spin-coating a spiro-OMeTAD solution.

[0012] In one possible implementation, the metal electrode is an Ag electrode.

[0013] On the other hand, this application provides a method for preparing a perovskite solar cell based on composite interface modification engineering, which includes the following steps: Step 1: Electron transport layer is prepared by depositing TiO2 on a conductive glass substrate using electron beam evaporation.

[0014] Step 2: MgF2 is deposited on the electron transport layer by electron beam evaporation to prepare the first interface modification layer.

[0015] Step 3: MgO is deposited on the first interface modification layer by electron beam evaporation to prepare the second interface modification layer.

[0016] Step 4: Spin-coating CsPbI onto the second interface modification layer. 3-x Br x Perovskite layers are prepared using a perovskite solution method.

[0017] Step 5: Prepare a hole transport layer on the perovskite layer by spin-coating a spiro-OMeTAD solution.

[0018] Step 6: Deposit Ag electrodes onto the hole transport layer using a thermal evaporation process to obtain a perovskite solar cell.

[0019] The perovskite solar cell and its preparation method based on composite interface modification engineering in this application have the following advantages: A composite interface modification layer based on a first interface modification layer and a second interface modification layer is constructed between the electron transport layer and the perovskite layer. The first interface modification layer uses MgF2 to regulate surface energy and microstructure smoothness and improve transmittance. The second interface modification layer uses MgO, which coordinates with / passivates defect sites and buffers the band structure, reducing non-radiative recombination and injection / extraction barriers at the interface, thereby improving open-circuit voltage and fill factor. In summary, this effectively reduces interfacial recombination between the perovskite layer and the electron transport layer, reduces energy loss, improves charge extraction efficiency, and provides an excellent barrier against the erosion of the perovskite layer by moisture and environmental factors, thus extending the battery's lifespan.

[0020] Furthermore, the composite interface modification layer improves substrate wettability, promotes the formation of larger grains and preferred orientation of perovskite, and reduces pinholes and grain boundary defects. At the same time, the low refractive index MgF2 provides local antireflection and optical coupling enhancement, reduces parasitic reflection and absorption, increases the effective light flux into the perovskite layer, and synergistically brings about an increase in short-circuit current density and weakens hysteresis, thus comprehensively improving device efficiency.

[0021] The proposed electron transport layer, first interface modification layer, and second interface modification layer are all prepared by electron beam evaporation deposition. This method offers controllable thickness, good batch-to-batch consistency, and facilitates integration with existing vacuum processes for electron transport layers, reducing sensitivity to environmental humidity and solvents and simplifying manufacturing. The high degree of automation of electron beam evaporation enables continuous and uniform thin film deposition, ensuring consistency and reliability in large-scale production. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 A schematic diagram of the structure of a perovskite solar cell based on composite interface modification engineering provided in an embodiment of this application; Figure 2 A comparison of the positive scan JV curves of the perovskite solar cell based on composite interface modification engineering and the control perovskite solar cell provided in the embodiments of this application. Figure 3 A comparison of the reverse scan JV curves of the perovskite solar cell based on composite interface modification engineering and the control perovskite solar cell provided in the embodiments of this application; Figure 4A comparison chart of aging times between a perovskite solar cell based on composite interface modification engineering and a control perovskite solar cell provided in the embodiments of this application. Detailed Implementation

[0024] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0025] like Figure 1 As shown, this application provides a perovskite solar cell based on composite interface modification engineering, comprising, from bottom to top: a conductive glass substrate, an electron transport layer, a first interface modification layer, a second interface modification layer, a perovskite layer, a hole transport layer, and a metal electrode.

[0026] The first interface modification layer uses MgF2, and the second interface modification layer uses MgO.

[0027] For example, the electron transport layer is made of TiO2.

[0028] For example, the electron transport layer, the first interface modification layer, and the second interface modification layer are all prepared by electron beam evaporation.

[0029] Specifically, in this embodiment, the conductive glass substrate is FTO conductive glass. Before preparing the electron transport layer, the FTO conductive glass is first ultrasonically treated with deionized water, acetone, isopropanol, and anhydrous ethanol for 20 minutes in sequence, and then dried with nitrogen gas.

[0030] Specifically, in this embodiment, the preparation process of the electron transport layer is as follows: 99.99% high-purity TiO2 black sintered particles are selected as the evaporation source, and high-temperature tape is used to protect the bottom electrode area. Cleaned FTO conductive glass is placed on a mask and then placed into a coating machine. The vacuum level is reduced to 10... -4 Under conditions where the substrate temperature reaches 200°C and the pressure is at 0.5 A / s, the TiO2 film deposition process begins. During deposition, the oxygen flow rate is maintained at 15 sccm until the entire deposition process is complete. After deposition, the sample is placed in an oxygen-rich tube furnace and annealed at 450°C for 2 hours to complete the preparation of the electron transport layer.

[0031] In this embodiment, the preparation process of the first interface modification layer and the second interface modification layer is similar to that of the electron transport layer, except that: the first interface modification layer is deposited on the electron transport layer and the evaporation source is changed to MgF2; the second interface modification layer is deposited on the first interface modification layer and the evaporation source is changed to MgO.

[0032] For example, the perovskite layer is spin-coated with CsPbI 3-x Br x The perovskite solution was prepared.

[0033] Specifically, in this embodiment, the perovskite layer preparation process is as follows: HPbI3, PbBr2, and CsI are added sequentially to 1 ml of a mixed solvent of DMF and DMSO in a stoichiometric ratio of 3:2.85:0.15 to prepare a 0.8 mol / L CsPbI3-xBrx perovskite solution. The solution is then stirred at room temperature for 12 h on a magnetic stirrer until completely dissolved. CsPbI3 is then stirred at 1000 rpm for 10 s, followed by 3000 rpm for 30 s. 3-x Br x The perovskite solution was spin-coated onto the second interface modification layer, and then immediately placed on a heating platform for annealing at 200°C for 5 minutes.

[0034] For example, the hole transport layer is prepared by spin-coating a spiro-OMeTAD solution.

[0035] Specifically, in this embodiment, the hole transport layer is prepared as follows: 72.3 mg of spiro-OMeTAD, 29 μL of TBP and 18 μL of Li-TFSI solution (520 mg of Li-TFSI dissolved in 1 mL of acetonitrile) are added to 1 mL of CB (chlorobenzene) to form a spiro-OMeTAD solution; the spiro-OMeTAD solution is spin-coated onto the perovskite layer at a speed of 7050 rpm for 30 s, and then annealed.

[0036] For example, the metal electrode is an Ag electrode.

[0037] Specifically, in this embodiment, the metal electrode is prepared as follows: an Ag electrode is deposited on the hole transport layer using a thermal evaporation process with a thickness of 70 nm and an evaporation rate controlled at around 2 A / s.

[0038] This application also provides a method for preparing a perovskite solar cell based on composite interface modification engineering, which includes the following steps: Step 1: Electron transport layer is prepared by depositing TiO2 on a conductive glass substrate using electron beam evaporation.

[0039] Step 2: MgF2 is deposited on the electron transport layer by electron beam evaporation to prepare the first interface modification layer.

[0040] Step 3: MgO is deposited on the first interface modification layer by electron beam evaporation to prepare the second interface modification layer.

[0041] Step 4: Spin-coating CsPbI onto the second interface modification layer. 3-x Br x Perovskite layers are prepared using a perovskite solution method.

[0042] Step 5: Prepare a hole transport layer on the perovskite layer by spin-coating a spiro-OMeTAD solution.

[0043] Step 6: Deposit Ag electrodes onto the hole transport layer using a thermal evaporation process to obtain a perovskite solar cell.

[0044] In one possible embodiment, the perovskite solar cell based on composite interface modification engineering of this application is compared with a control perovskite solar cell, the control perovskite solar cell not containing a composite interface modification layer. Figure 2 and Figure 3 The figures show a comparison of the forward and reverse scan JV curves of the perovskite solar cell based on the composite interface modification engineering and a control perovskite solar cell, respectively. The composite interface modification layer curve represents the JV curve of the perovskite solar cell based on the composite interface modification engineering, and the control curve represents the JV curve of the control perovskite solar cell. The horizontal axis represents voltage, and the vertical axis represents current density. Figure 2 and Figure 3 As can be seen, the perovskite solar cell based on composite interface modification engineering in this application achieves an open-circuit voltage of 1.13 V, a short-circuit current density of 19.66 mA / cm², and a fill factor of 81.9%, thereby increasing the photoelectric conversion efficiency to 18.12%. Figure 4 The figure shows a comparison of the aging times of the perovskite solar cell based on the composite interface modification engineering and a control perovskite solar cell. The curve representing the composite interface modification layer is the aging time curve of the perovskite solar cell based on the composite interface modification engineering, and the curve representing the control perovskite solar cell is the aging time curve of the control perovskite solar cell. The horizontal axis, Time, represents time, and the vertical axis, Normalized PCE, represents the power conversion efficiency. Figure 4As can be seen, during the 72-hour natural placement test, the perovskite solar cell based on composite interface modification engineering of this application maintained more than 90% of its original efficiency, while the efficiency of the control perovskite solar cell without the composite interface modification layer dropped to about 60% of its original efficiency. This significant improvement demonstrates that the perovskite solar cell based on composite interface modification engineering of this application can maintain stable performance during long-term operation.

[0045] This application embodiment constructs a composite interface modification layer between the electron transport layer and the perovskite layer, based on a first interface modification layer and a second interface modification layer. The first interface modification layer uses MgF2 to regulate surface energy and microscopic smoothness, and improve transmittance. The second interface modification layer uses MgO, which coordinates with / passivates defect sites and achieves bandgap buffering, reducing interfacial nonradiative recombination and injection / extraction barriers, thereby improving open-circuit voltage and fill factor. In summary, this effectively reduces interfacial recombination between the perovskite layer and the electron transport layer, reduces energy loss, improves charge extraction efficiency, and provides an excellent barrier against the erosion of the perovskite layer by moisture and environmental factors, thus extending battery life.

[0046] Furthermore, the composite interface modification layer improves substrate wettability, promotes the formation of larger grains and preferred orientation of perovskite, and reduces pinholes and grain boundary defects. At the same time, the low refractive index MgF2 provides local antireflection and optical coupling enhancement, reduces parasitic reflection and absorption, increases the effective light flux into the perovskite layer, and synergistically brings about an increase in short-circuit current density and weakens hysteresis, thus comprehensively improving device efficiency.

[0047] The proposed electron transport layer, first interface modification layer, and second interface modification layer are all prepared by electron beam evaporation deposition. This method offers controllable thickness, good batch-to-batch consistency, and facilitates integration with existing vacuum processes for electron transport layers, reducing sensitivity to environmental humidity and solvents and simplifying manufacturing. The high degree of automation of electron beam evaporation enables continuous and uniform thin film deposition, ensuring consistency and reliability in large-scale production.

[0048] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0049] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A perovskite solar cell based on composite interface modification engineering, characterized in that, include: From bottom to top: conductive glass substrate, electron transport layer, first interface modification layer, second interface modification layer, perovskite layer, hole transport layer, and metal electrode; The first interface modification layer uses MgF2, and the second interface modification layer uses MgO; The electron transport layer is made of TiO2; The electron transport layer, the first interface modification layer, and the second interface modification layer are all prepared by electron beam evaporation.

2. The perovskite solar cell based on composite interface modification engineering according to claim 1, characterized in that, The perovskite layer is spin-coated with CsPbI. 3-x Br x The perovskite solution was prepared.

3. The perovskite solar cell based on composite interface modification engineering according to claim 1, characterized in that, The hole transport layer was prepared by spin-coating a spiro-OMeTAD solution.

4. The perovskite solar cell based on composite interface modification engineering according to claim 1, characterized in that, The metal electrode is an Ag electrode.

5. A method for preparing a perovskite solar cell based on composite interface modification engineering, used to prepare a perovskite solar cell based on composite interface modification engineering as described in any one of claims 1 to 4, characterized in that, Includes the following steps: Step 1: Deposit TiO2 on a conductive glass substrate using electron beam evaporation to prepare an electron transport layer; Step 2: MgF2 is deposited on the electron transport layer by electron beam evaporation to prepare the first interface modification layer; Step 3: MgO is deposited on the first interface modification layer by electron beam evaporation to prepare the second interface modification layer; Step 4: Spin-coating CsPbI onto the second interface modification layer. 3-x Br x Perovskite layers were prepared using a perovskite solution method; Step 5: Prepare a hole transport layer on the perovskite layer by spin-coating a spiro-OMeTAD solution; Step 6: Deposit Ag electrodes onto the hole transport layer using a thermal evaporation process to obtain a perovskite solar cell.

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