Perovskite solar cell doped with glutamic acid coumarin derivative and preparation method thereof

Abstract

The application discloses a perovskite solar cell, which comprises a conductive substrate, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer and an electrode layer from bottom to top, wherein the perovskite light-absorbing layer is doped with glutamic acid coumarin derivative, and the structure is shown in the following formula. The application further discloses a preparation method of the perovskite solar cell. The perovskite light-absorbing layer is prepared by doping glutamic acid coumarin derivative in a perovskite precursor solution, which promotes the absorption of sunlight by the perovskite thin film, regulates the stress of the perovskite light-absorbing layer, improves the surface energy of the perovskite precursor, reduces the recombination of photo-generated carriers of the perovskite solar cell, and makes the prepared perovskite solar cell have excellent photoelectric conversion efficiency and stability, and has a wide application prospect.

Description

Technical Field

[0001] This invention belongs to the field of perovskite solar cell technology, specifically relating to a perovskite solar cell doped with glutamic acid coumarin derivatives and its preparation method. Background Technology

[0002] Solar cells directly convert solar energy into electrical energy using the photovoltaic effect. Due to the complex manufacturing process and high cost of silicon-based solar cells, there is an urgent need to develop a simple and low-cost solar cell technology. Perovskite solar cells have the greatest potential among all types of cells.

[0003] After just over a decade of development, the photoelectric conversion efficiency of perovskite solar cells has reached 26.1%. However, the long-term operational stability of these devices remains a problem, leaving their future uncertain. Due to the complex composition and soft lattice characteristics of perovskite solar cells, external factors such as light, temperature, and humidity can easily induce ion migration within the perovskite layer, leading to aging and decomposition of the perovskite light-absorbing layer and severely impacting the device's efficiency and stability. Therefore, the fabrication of high-quality perovskite light-absorbing layers is of great significance.

[0004] The quality of the light-absorbing layer in a perovskite solar cell affects the device's performance. Doping the perovskite precursor solution with appropriate additives can increase the number of perovskite crystallization sites, promote perovskite crystallization, and thus regulate the perovskite film quality. The addition of additives can also affect the perovskite energy level arrangement, reduce defect state density, and promote carrier extraction, thereby influencing the photoelectric conversion efficiency and long-term stability of the perovskite solar cell.

[0005] Patent document CN112436091B discloses a novel rare-earth ion-doped perovskite solar cell, comprising, from top to bottom, a counter electrode (Au), a hole transport layer (SpiroOMeTAD), a perovskite light-absorbing layer (Cs2AgBiBr6), an electron transport layer (SnO2), and a transparent conductive glass substrate (ITO); the rare-earth ions are cerium and ytterbium, etc. This invention, based on the traditional FTO / SnO2 / Cs2AgBiBr6 / SpiroOMeTAD / Au device structure, reduces the bandgap and broadens the spectral absorption range by doping the Cs2AgBiBr6 perovskite light-absorbing layer with rare earth elements, thereby improving the photoelectric conversion efficiency of the perovskite solar cell.

[0006] Patent document CN110854271A discloses a highly stable perovskite solar cell and its fabrication method. The solar cell, from bottom to top, comprises a conductive glass layer, a dense electron transport layer, a perovskite light-absorbing layer, a hole transport layer, and a counter electrode layer. This invention achieves a high open-circuit voltage by adding DPSI (3-(decyldimethylammonium)-propanesulfonic acid inner salt) and PbCl2 to the light-absorbing layer of the perovskite cell, through the synergistic effect of these two additives. This invention, through elemental regulation and additive defect passivation, not only solves the key problem of low stability hindering the commercialization of perovskite solar cells, but also addresses the issue of lower photoelectric conversion efficiency of binary perovskite solar cells compared to ternary perovskite solar cells.

[0007] Although existing technologies have made some progress in the research of perovskite solar cells, due to the ionic and polycrystalline characteristics of perovskite itself, the perovskite film undergoes inconsistent thermal expansion and cooling contraction during annealing, which inevitably generates residual stress in the perovskite film, thereby inducing defects and phase separation. These defects usually become sites for non-radiative charge recombination, and phase separation seriously affects the stability of perovskite, thus affecting the performance and lifespan of the device. Summary of the Invention

[0008] To address the aforementioned technical problems, this invention provides a perovskite solar cell doped with glutamic acid coumarin derivatives. The perovskite light-absorbing layer of this solar cell is doped with glutamic acid coumarin derivatives, exhibiting high photoelectric conversion efficiency and stability.

[0009] A perovskite solar cell doped with a glutamate coumarin derivative includes, from bottom to top, a conductive substrate, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer, and an electrode layer, wherein the perovskite light-absorbing layer is doped with a glutamate coumarin derivative.

[0010] The perovskite solar cell of this invention incorporates a glutamic acid coumarin derivative in its perovskite light-absorbing layer. Doping the perovskite precursor solution with this derivative releases residual stress generated during perovskite thermal annealing, effectively suppresses phase separation in the perovskite film, passivates anion and cation defects in the perovskite film, thereby slowing down the device's decomposition rate and improving its stability. Furthermore, the doping with the glutamic acid coumarin derivative promotes the absorption of sunlight by the perovskite film and shifts the HUMO and LUMO energy levels, creating an energy level arrangement favorable for electron and hole transport, promoting carrier extraction, and thus enhancing the device's photoelectric performance.

[0011] Preferably, the structural formula of the glutamic acid coumarin derivative is as follows:

[0012]

[0013] Among them, n is an integer from 1 to 10, R is methyl or ethyl, and X is F, Cl, Br or I.

[0014] Preferably, the conductive substrate is FTO or ITO.

[0015] Preferably, the hole transport layer material is MeO-2PACz.

[0016] Preferably, the perovskite light-absorbing layer material includes FAPbI3, MAPbBr3 or CsPb(I , , , , , , , , , , 61 ,

[0027] ,

[0022] ,

[0026] ,

[0021] ,

[0025] ,

[0020] ,

[0024] ,

[0019] ,

[0023] ,

[0018] Br 1-x )3, where one or more of 0 < x < 1.

[0017] Preferably, the electron transport layer material is PC 61 BM.

[0018] Preferably, the electrode layer material is Ag, and the thickness is 80 - 100 nm.

[0019] Preferably, the perovskite solar cell further includes an electron transport modification layer, and the electron transport modification layer is located between the electron transport layer and the electrode layer.

[0020] Preferably, the electron transport modification layer material is BCP.

[0021] The present invention also provides a preparation method of the above perovskite solar cell. By doping a glutamic acid coumarin derivative into a perovskite precursor solution, a high-quality perovskite thin film is prepared, so that the prepared perovskite solar cell has excellent optoelectronic properties and stability.

[0022] A preparation method of the above perovskite solar cell includes the following steps:

[0023] (1) Spin-coat a hole transport material on a conductive substrate and anneal to obtain a hole transport layer;

[0024] (2) Coat a perovskite precursor solution doped with a glutamic acid coumarin derivative on the hole transport layer obtained in step (1) and anneal to obtain a perovskite light-absorbing layer;

[0025] (3) Coat an electron transport material on the perovskite light-absorbing layer obtained in step (2) and anneal to obtain an electron transport layer;

[0026] (4) Evaporate an electrode material on the electron transport layer obtained in step (3) to obtain the perovskite solar cell.

[0027] Preferably, in step (1), the hole transport material is a SAM solution, the solute of the SAM solution is MeO-2PACz, the solvent is ethanol, and the concentration of the SAM solution is 0.1~1.0 mg / ml.

[0028] More preferably, the concentration of the SAM solution is 0.1~0.5 mg / ml.

[0029] Preferably, in step (1), the annealing temperature is 100~150 ℃ and the time is 10~20 min.

[0030] Preferably, in step (2), the method for preparing the perovskite precursor solution doped with glutamic acid coumarin derivative is as follows: add the glutamic acid coumarin derivative to the perovskite precursor solution and heat and stir.

[0031] Preferably, the heating temperature is 50-80 ℃ and the stirring time is 30 min.

[0032] Preferably, the solute in the perovskite precursor solution includes FAPbI3, MAPbBr3, or CsPb(I) x Br 1-x )3, wherein 0 < x < 1 or more of them, and the solvent includes at least one of N, N-dimethylformamide, dimethyl sulfoxide or N-methylpyrrolidone.

[0033] Preferably, the doping amount of the glutamic acid coumarin derivative in the perovskite precursor solution is 0.1~10 mg / mL.

[0034] More preferably, the doping amount of the glutamic acid coumarin derivative in the perovskite precursor solution is 0.1~5 mg / mL.

[0035] Preferably, in step (2), the annealing temperature is 100~150 ℃ and the annealing time is 30~60 min.

[0036] Preferably, in step (2), an antisolvent is added dropwise during the process of coating the perovskite precursor solution doped with glutamic acid coumarin derivative onto the hole transport layer.

[0037] Preferably, the antisolvent includes diethyl ether, ethyl acetate, chlorobenzene, or anisole.

[0038] Preferably, in step (3), the electron transport material is PC. 61 BM's chlorobenzene solution, the PC 61 The concentration of BM's chlorobenzene solution is 10~25 mg / ml.

[0039] Preferably, in step (3), the annealing temperature is 60-70 °C and the time is 5-10 min.

[0040] Preferably, after step (3), the electron transport layer is further coated with an electron transport modification material and annealed to obtain the electron transport modification layer.

[0041] Preferably, the electron transport modifier is an isopropanol solution of BCP, and the concentration of the isopropanol solution of BCP is 0.5~1.0 mg / ml.

[0042] Preferably, the annealing temperature for preparing the electron transport modification layer is 100-120 °C, and the annealing time is 10-15 min.

[0043] Compared with the prior art, the present invention has at least the following beneficial effects:

[0044] (1) The perovskite light-absorbing layer of the perovskite solar cell of the present invention is doped with a glutamic acid coumarin derivative. Doping the perovskite precursor solution with the glutamic acid coumarin derivative can release the residual stress generated during the thermal annealing of the perovskite, effectively suppress the phase separation of the perovskite film, passivate the anion and cation defects in the perovskite film, thereby slowing down the decomposition rate of the device and improving the stability of the device. In addition, the doping with the glutamic acid coumarin derivative can promote the absorption of sunlight by the perovskite film, and at the same time cause the HUMO and LUMO energy levels of the perovskite film to shift, forming an energy level arrangement that is conducive to electron and hole transport, promoting the extraction of charge carriers, and thus improving the photoelectric performance of the device.

[0045] (2) This invention obtains high-quality perovskite thin films by doping glutamic acid coumarin derivatives into a perovskite precursor solution, and then prepares perovskite solar cells with excellent photoelectric conversion efficiency and stability. The preparation method of this invention is simple and easy to operate, and is suitable for large-scale production. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the layered structure of the perovskite solar cell doped with glutamic acid coumarin derivative in the embodiment.

[0047] Figure 2 The JV curves are shown for the perovskite solar cells of the examples and comparative examples.

[0048] Figure 3 The diagram shows the steady-state output of perovskite solar cells in the examples and comparative examples.

[0049] Figure 4 The UV-Vis absorption spectra of the perovskite light-absorbing layers in the examples and comparative examples are shown.

[0050] Figure 5 The X-ray photoelectron spectra of the perovskite light-absorbing layers in the examples and comparative examples are shown.

[0051] Where a, b, and c are the Pb of the comparative perovskite light-absorbing layer, respectively. 4f I 3d O 1s X-ray photoelectron spectroscopy; d, e, and f are the Pb of the perovskite absorbing layer in the example, respectively. 4f I 3d O 1s X-ray photoelectron spectroscopy.

[0052] Figure 6 The ultraviolet photoelectron spectra of the perovskite light-absorbing layers in the examples and comparative examples are shown.

[0053] Where a is the maximum valence band value (VBM); b is the secondary electron cutoff edge.

[0054] Figure 7 The PL spectra of the perovskite light-absorbing layers in the examples and comparative examples are shown.

[0055] Figure 8 The TRPL spectra of the perovskite light-absorbing layers in the examples and comparative examples are shown.

[0056] Figure 9 The grazing incidence X-ray diffraction patterns of the perovskite absorbing layers in the examples and comparative examples are shown below.

[0057] Wherein, a is the grazing incidence X-ray diffraction pattern of the perovskite absorbing layer in the comparative example; b is the grazing incidence X-ray diffraction pattern of the perovskite absorbing layer in the example; c is the perovskite absorbing layer of the example and the comparative example. 2θ-sin2φ Linear fitting plot. Detailed Implementation

[0058] To make the objectives, features, and advantages of this invention more readily apparent, specific embodiments of the invention are described in detail below with reference to the accompanying drawings. However, the implementation and protection of this invention are not limited thereto. It should be noted that any processes not specifically described in detail below are methods that can be implemented or understood by those skilled in the art by referring to existing technology.

[0059] This invention provides a perovskite solar cell doped with a glutamate coumarin derivative. The structure of the perovskite solar cell, from bottom to top, consists of: a transparent conductive glass substrate (FTO), a MeO-2PACz hole transport layer, a perovskite light-absorbing layer, and a PC layer. 61 BM electron transport layer, BCP electron transport modification layer, and anode electrode.

[0060] The fabrication process of the doped perovskite solar cell according to an embodiment of the present invention includes the following steps:

[0061] Step S1: Cleaning the conductive glass substrate. The FTO conductive glass was sequentially ultrasonicated for 25 min in ultrapure water with detergent, ultrapure water, acetone, and isopropanol. The cleaned FTO conductive glass was dried with nitrogen gas and then treated with ultraviolet ozone for 30 min to obtain a clean FTO conductive glass substrate. During the ultraviolet ozone treatment, the strong oxidizing properties of O3 are used to clean residual organic matter on the FTO surface. Simultaneously, it increases the number of oxygen vacancies on the FTO surface, improving the work function and surface activity of the FTO conductive glass, which is beneficial for the preparation of the hole transport layer.

[0062] Step S2: Spin-coat SAM solution onto the FTO conductive glass substrate treated in step S1 at a spin speed of 2000 rpm for 30 s, and anneal at 100 °C for 15 min to obtain a hole transport layer.

[0063] Step S3: Add an appropriate amount of glutamic acid coumarin derivative to the perovskite precursor solution, heat and stir to obtain a perovskite precursor solution containing glutamic acid coumarin derivative; spin-coat the perovskite precursor solution containing glutamic acid coumarin derivative onto the hole transport layer obtained in step S2, spin-coat at 3000 rpm for 30 s, add 400 µL of diethyl ether antisolvent at the 15th s, and anneal the perovskite-coated FTO substrate at 100 ℃ for 60 min to obtain a perovskite light-absorbing layer.

[0064] Step S4: Spin-coat an electron transport layer onto the surface of the perovskite light-absorbing layer.

[0065] Step S5: Spin-coat an electron transport modification layer onto the surface of the electron transport layer.

[0066] Step S6: Deposit a silver electrode on the surface of the electron transport modification layer to obtain an electrode layer with a thickness of 80~100 nm.

[0067] After the above steps are completed, a perovskite solar cell doped with glutamic acid coumarin derivatives is obtained.

[0068] The superior embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0069] Example

[0070] The structure of the doped glutamate coumarin derivative perovskite solar cell device in this embodiment is: FTO / SAM / perovskite light-absorbing layer / PC 61 BM / BCP / Ag.

[0071] The method for preparing the perovskite solar cell doped with glutamic acid coumarin derivatives in this embodiment includes the following steps:

[0072] Step S1: The FTO conductive glass is ultrasonically cleaned for 25 minutes in a series of ultrapure water, detergent, acetone and isopropanol. The cleaned FTO conductive glass is dried with nitrogen and then treated with ultraviolet ozone for 30 minutes to obtain a clean FTO conductive glass substrate.

[0073] Step S2: Dissolve 0.5 mg of MeO-2PACz (SAM) in 1 mL of anhydrous ethanol and stir at room temperature for 2 h to obtain a SAM solution. Add 70 µL of SAM solution to an FTO glass substrate, let stand for 10 s, spin coat at 4000 rpm for 40 s, and anneal the SAM-coated FTO substrate at 100 °C for 15 min to obtain a hole transport layer.

[0074] Step S3: Dissolve 0.5068 g PbI2, 0.2010 g FAI, 0.0058 g MABr, 0.024 g PbBr2, 0.0097 g MACl, and 0.0173 g CsI in a mixed solvent of 800 µL DMF and 150 µL DMSO, and add 1.0 mg of glutamic acid coumarin derivative. Stir at 70 °C for 4 h to obtain a perovskite precursor solution doped with glutamic acid coumarin derivative. Take 60 µL of the perovskite precursor solution doped with glutamic acid coumarin derivative and add it dropwise onto the hole transport layer obtained in step S2. Spin coat at 3000 rpm for 30 s. At the 15th s, add 400 µL of diethyl ether antisolvent. Anneal the FTO substrate coated with perovskite at 100 °C for 60 min to obtain a perovskite light-absorbing layer. The structural formula of the glutamic acid coumarin derivative used in this embodiment is as follows:

[0075] Step S4: Add 20 mg PC 61 PC was prepared by dissolving BM in 1 mL of chlorobenzene. 61 BM solution. Add 55 µL of PC 61 BM chlorobenzene solution was dropped onto the perovskite light-absorbing layer obtained in step S3, and spin-coated at 3000 rpm for 30 s. The substrate was then annealed at 80 ℃ for 3 min to obtain the electron transport layer.

[0076] Step S5: Dissolve 0.8 mg BCP in 1 mL of isopropanol to prepare a BCP solution. Drop 90 µL of the BCP solution onto the electron transport layer obtained in step S4, spin coat at 4000 rpm for 30 s, and anneal the substrate at 100 °C for 15 min to obtain the electron transport modified layer.

[0077] Step S6: Vacuum thermal evaporation is used to deposit 80 nm of silver as an electrode on the electron transport modification layer obtained in step S5 to obtain a perovskite solar cell doped with glutamic acid coumarin derivative.

[0078] Comparative Example

[0079] In this comparative example, no glutamic acid coumarin derivative was doped during step S3 when preparing the perovskite precursor solution; the rest was the same as in the example.

[0080] Specifically, step S3 of this comparative example is as follows: 0.5068 g PbI2, 0.2010 g FAI, 0.0058 g MABr, 0.024 g PbBr2, 0.0097 g MACl and 0.0173 g CsI are dissolved in a mixed solvent of 800 µL DMF and 150 µL DMSO and stirred at 70 °C for 4 h to obtain a perovskite precursor solution without glutamic acid coumarin derivatives. This solution is then dropped onto the hole transport layer obtained in step (2) and spin-coated to obtain a perovskite light-absorbing layer.

[0081] Performance testing

[0082] Under standard test conditions (AM 1.5G illumination), the JV characteristics of the perovskite solar cells prepared in the examples and comparative examples were tested, and the results are shown in Table 1 and 2. Figure 2-3 .

[0083] Table 1 Performance parameters of solar cells in the examples and comparative examples

[0084]

[0085] From Table 1 and Figure 2-3 It is evident that doping the perovskite light-absorbing layer with glutamic acid coumarin derivatives promotes the improvement of short-circuit current, open-circuit voltage, and fill factor of perovskite solar cell devices. The energy conversion efficiency increases from 23.19% in the comparative example to 24.84% in the embodiment, demonstrating that the perovskite solar cells doped with glutamic acid coumarin derivatives have superior performance.

[0086] Figure 4 The images show the UV-Vis absorption spectra of the perovskite absorbing layers in the examples and comparative examples. Figure 4 As shown, compared to the comparative example, the absorbance of the perovskite light-absorbing layer in the embodiment is significantly improved, indicating that the doping of glutamic acid coumarin derivatives promotes the absorption of natural light by the perovskite light-absorbing layer.

[0087] The interaction between glutamate coumarin derivatives and perovskite was analyzed using X-ray photoelectron spectroscopy. The test results are as follows: Figure 5As shown in the figure, the addition of the glutamic acid coumarin derivative in the examples resulted in a decrease in Pb compared to the comparative example. 4f , I 3d O 1s The characteristic peaks shifted toward the direction of lower binding energy, indicating that the glutamic acid coumarin derivative interacted with the perovskite.

[0088] The energy level changes of the perovskite absorbing layers in the comparative and examples were characterized using ultraviolet photoelectron spectroscopy, such as... Figure 6 As shown, a is the valence band maximum (VBM), and b is the secondary electron cutoff edge. Figure 6 This indicates that the addition of glutamic acid coumarin derivatives altered the energy levels of the perovskite film, forming an energy level arrangement that promotes hole and electron transport.

[0089] Figure 7 and Figure 8 The PL and TRPL spectra of the perovskite absorbing layers in the comparative and examples are shown. Figure 7 and Figure 8 As shown, the PL intensity of the perovskite light-absorbing layer in the embodiment is significantly increased compared to the comparative example, indicating that doping the perovskite precursor with glutamic acid coumarin derivatives effectively passivates defects in the perovskite film and significantly increases the carrier lifetime.

[0090] The surface stress variation of the perovskite light-absorbing layer in the examples and comparative examples was characterized using grazing incidence X-ray diffraction, and the results are as follows: Figure 9 As shown, a is the grazing incidence X-ray diffraction pattern of the perovskite absorbing layer in the comparative example; b is the grazing incidence X-ray diffraction pattern of the perovskite absorbing layer in the example; c is the perovskite absorbing layer of the example and the comparative example. 2θ-sin2φ The linear fitting plot shows that the perovskite thin film of the example... 2θ-sin2φ The smaller slope of the linear fit indicates that the stress inside the perovskite film is effectively released after glutamic acid coumarin doping.

[0091] This invention is not limited to the specific technical solutions described in the above embodiments and comparative examples. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention (such as the length n of the carbon chain of the glutamic acid coumarin derivative, and the types of terminal groups R and X) are within the scope of protection claimed by this invention.

Claims

1. A perovskite solar cell doped with glutamic acid coumarin derivatives, comprising, from bottom to top, a conductive substrate, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer, and an electrode layer, characterized in that, The perovskite light-absorbing layer is doped with a glutamic acid coumarin derivative; The structural formula of the glutamic acid coumarin derivative is as follows: Wherein, n is an integer from 1 to 10, R is methyl or ethyl, and X is F, Cl, Br or I.

2. The perovskite solar cell according to claim 1, characterized in that, The perovskite solar cell further includes an electron transport modification layer, which is located between the electron transport layer and the electrode layer.

3. The method for preparing a perovskite solar cell according to any one of claims 1-2, characterized in that, Includes the following steps: (1) A hole transport material is spin-coated onto a conductive substrate and annealed to obtain a hole transport layer; (2) Coat the hole transport layer obtained in step (1) with a perovskite precursor solution doped with glutamic acid coumarin derivative, and anneal to obtain a perovskite light-absorbing layer. (3) Coat the perovskite light-absorbing layer obtained in step (2) with an electron transport material, and anneal it to obtain an electron transport layer; (4) Electrode material is deposited on the electron transport layer obtained in step (3) to obtain the perovskite solar cell.

4. The preparation method according to claim 3, characterized in that, In step (2), the method for preparing the perovskite precursor solution doped with glutamic acid coumarin derivative is as follows: add the glutamic acid coumarin derivative to the perovskite precursor solution and heat and stir.

5. The preparation method according to claim 4, characterized in that, The heating temperature is 50-80℃, and the stirring time is 30 min.

6. The preparation method according to claim 3, characterized in that, In step (2), the solute in the perovskite precursor solution includes FAPbI3, MAPbBr3, or CsPb(I) x Br 1-x )3, wherein 0 < x < 1 or more, and the solvent includes at least one of N, N-dimethylformamide, dimethyl sulfoxide or N-methylpyrrolidone.

7. The preparation method according to claim 6, characterized in that, The doping amount of the glutamic acid coumarin derivative in the perovskite precursor solution is 0.1~10 mg / mL.

8. The preparation method according to claim 4, characterized in that, In step (2), the annealing temperature is 100~150 ℃ and the annealing time is 30~60 min.

9. The preparation method according to claim 4, characterized in that, In step (2), an antisolvent is added dropwise during the process of coating the perovskite precursor solution doped with glutamic acid coumarin derivatives onto the hole transport layer.

Images