Application of bulk phase and interface synergistic passivator in perovskite solar cell

Abstract

The invention belongs to the field of perovskite solar cells, and particularly relates to application of a bulk phase and interface synergistic passivator in a perovskite solar cell. The invention provides a bulk phase / interface synergistic passivation innovative strategy, molecules with a tricyclic sulfur-nitrogen heterocyclic ring structure are introduced as a synergistic passivator, and defect global repair of each functional layer of a device is realized. The molecular design of the structural derivative taking phenothiazine as the core has the following advantages: skeleton characteristics: a conjugated tricyclic system forms an electron transport network through pi-pi stacking, endows molecules with excellent electron delocalization ability, and effectively regulates and controls carrier kinetics; the thioether group is used for dynamically repairing an ion migration channel through oxidation-reduction activity and inhibiting formation of deep-energy-level defects; and the secondary amine group is used as a hydrogen bond donor for anchoring uncoordinated halide ions and synchronously passivating surface and grain boundary defects.

Description

Technical Field

[0001] This invention belongs to the field of perovskite solar cells, specifically relating to the application of bulk and interfacial synergistic passivators in perovskite solar cells. Background Technology

[0002] Perovskite photovoltaic technology has experienced rapid development over the past decade, achieving a leap in single-junction cell efficiency from 3.8% to 27.0% through innovations in structural design and fabrication methods. Inverted perovskite solar cells, with their excellent stability, high efficiency, low cost, low-temperature processing characteristics, and compatibility with tandem cells, have become a research focus in the photovoltaic field in recent years. However, the intrinsic ion migration tendency of perovskite materials and the non-radiative recombination problem caused by interface defects severely limit the efficiency limit and long-term stability of devices. To suppress defect characteristics, passivators are widely introduced into the perovskite bulk phase or interface to reduce carrier loss through mechanisms such as chemical bonding, energy level modulation, or physical shielding.

[0003] Traditional passivators still face challenges: their action is limited to a single dimension, with most molecules targeting only the perovskite layer or a single interface, lacking the ability to passivate defects in the hole transport layer and the perovskite-metal electrode interface, making it difficult to eliminate cross-interface recombination; their dynamic adaptability is insufficient, and static passivation strategies are unable to cope with the dynamic regeneration of defects caused by light, humidity, or electric fields during device operation, resulting in continuous efficiency degradation.

[0004] In perovskite solar cells (PSCs), passivation engineering has greatly improved the efficiency and stability of PSCs. However, traditional passivating agents typically target defects in the bulk phase of the perovskite layer or at a specific interface, failing to address defects in the electron transport layer, hole transport layer, and the perovskite layer as a whole. Furthermore, most passivating agents only statically cover defect sites, making them susceptible to molecular desorption or degradation during device operation under illumination, thus failing to dynamically repair newly formed defects. Summary of the Invention

[0005] This invention aims to improve the wettability of perovskite solution on the hole transport layer by incorporating phenothiazine molecules, thereby reducing nanopores and releasing stress at the buried interface. This also homogenizes the distribution of holes in the hole transport layer, promoting carrier extraction and reducing nonradiative recombination between holes and the perovskite interface.

[0006] To address the aforementioned technical problems, this application provides the following technical solution:

[0007] This invention provides the application of a bulk and interface synergistic passivator in perovskite solar cells, wherein the bulk and interface synergistic passivator is a phenothiazine compound; the perovskite solar cell includes an electrode, an electron transport layer, a perovskite layer, a hole transport layer and a transparent electrode arranged sequentially; the raw materials of the electron transport layer, the perovskite layer and the hole transport layer all include the bulk and interface synergistic passivator.

[0008] Preferably, the phenothiazine compound is phenothiazine (PTZ), 10-methylphenothiazine, 2-chlorophenothiazine, or 2-acetylphenothiazine.

[0009] Preferably, the electron transport layer in the perovskite solar cell is obtained by spin-coating a mixture of PCBM ((6,6)-phenyl-C61-butyrate, CAS No.: 160848-22-6) and phenothiazine in chlorobenzene onto the surface of the perovskite layer.

[0010] Furthermore, the mass ratio of PCBM to phenothiazine is 8-12:1.

[0011] Furthermore, the spin coating speed is 1000 rpm, the time is 30 s, and the acceleration is 500 rpm / s.

[0012] Preferably, the perovskite layer in the perovskite solar cell is prepared by the following method:

[0013] S11: The perovskite precursor solution and phenothiazine are mixed and then spin-coated onto the surface of the hole transport layer in two separate steps.

[0014] S12: Add chlorobenzene to the mixture after spin coating in step S11, and anneal at 95-105℃ for 15-20 minutes.

[0015] The perovskite precursor solution is obtained by adding cesium iodide, formamide iodide (FAI), and lead iodide to a mixed solvent; wherein the mixed solvent is composed of N,N-dimethylformamide and dimethyl sulfoxide in a volume ratio of 3-5:1.

[0016] Furthermore, the solute in the perovskite precursor solution is FA. 0.95 Cs 0.05 PbI3 perovskite, wherein the mass ratio of solute to phenothiazine is 8-12:1.

[0017] Furthermore, the spin coating method is as follows: spin coating once at 1000 rpm for 10 seconds, followed by a second spin coating at 3000 rpm for 30 seconds.

[0018] Furthermore, the acceleration of the first spin coating is 1000 rpm / s, and the acceleration of the second spin coating is 3000 rpm / s.

[0019] Preferably, the transparent electrode is selected from an ITO conductive glass substrate.

[0020] Preferably, the hole transport layer in the perovskite solar cell is obtained by spin-coating a mixture of [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphate (MeO-4PACz, CAS No. 2922526-56-3) and phenothiazine in anhydrous ethanol onto the surface of a transparent electrode.

[0021] Furthermore, the spin coating speed is 4000 rpm and the time is 30 s.

[0022] Furthermore, the mass ratio of [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphoric acid to phenothiazine is 2-4:1.

[0023] Preferably, the electrode is selected from metal Ag electrodes.

[0024] The technical solution of the present invention has the following advantages compared with the prior art:

[0025] Bulk and interfacial synergistic passivating agents, as an emerging cross-layer passivation strategy, provide a breakthrough solution for achieving full-interface defect suppression through the multifunctional integration of molecular structures and innovative design of action mechanisms.

[0026] The core advantages of this type of passivator are: through the synergistic effect of multiple functional groups, it can simultaneously anchor the defect sites of the perovskite active layer, electron transport layer and hole transport layer; by utilizing dynamic bonding and self-healing properties, it can continuously repair newly formed defects during device service; and through energy level gradient optimization and process compatibility design, it can maximize the cross-layer charge transport efficiency and simplify the fabrication process.

[0027] This invention proposes an innovative bulk / interface synergistic passivation strategy. By introducing molecules with tricyclic sulfur-nitrogen heterocyclic structures as synergistic passivating agents, it achieves full-domain defect repair in all functional layers of the device. The molecular design of these phenothiazine-based structural derivatives (such as 10-methylphenothiazine, 2-chlorophenothiazine, 2-acetylphenothiazine, etc.) offers the following advantages:

[0028] Framework characteristics: The conjugated tricyclic system forms an electron transport network through π-π stacking, endowing the molecule with excellent electron delocalization ability and effectively regulating carrier dynamics; thioether groups: dynamically repair ion migration channels through redox activity and inhibit the formation of deep-level defects; secondary amine groups: act as hydrogen bond donors to anchor uncoordinated halide ions and simultaneously passivate surface and grain boundary defects. Attached Figure Description

[0029] Figure 1 This invention describes the processing method and purpose for preparing perovskite solar cells.

[0030] Figure 2 This is a schematic diagram (A) of a perovskite solar cell structure.

[0031] Figure 3 This is a schematic diagram (B) of a perovskite solar cell structure.

[0032] Explanation of reference numerals in the attached figures: 1-electrode, 2-electron transport layer, 3-perovskite layer, 4-hole transport layer, 5-transparent electrode. Detailed Implementation

[0033] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0034] Example 1:

[0035] The solution is prepared as follows:

[0036] Hole transport layer solution: Dissolve hole transport material SAM (MeO-4PACz) powder in anhydrous ethanol to prepare a solution with a concentration of 0.5 mg / mL, and mix it with phenothiazine powder; the mass fraction ratio of the two is 3:1.

[0037] Perovskite precursor solution: composition FA 0.95 Cs 0.05 PbI3 perovskite was prepared by mixing CsI, FAI and PbI2 in a mixed solvent of DMF:DMSO = 4:1 (volume ratio) in stoichiometric ratio to prepare a 1.5 M perovskite precursor solution; then it was mixed with phenothiazine powder in a molar mass ratio of 10:1.

[0038] Electron transport solution: Dissolve 20 mg / mL of PCBM solution in chlorobenzene (CB) and mix with phenothiazine powder in a molar ratio of 10:1.

[0039] The device fabrication method is as follows:

[0040] (1) Cleaning and UV-ozone treatment of ITO conductive glass substrate

[0041] The ITO substrate was ultrasonically cleaned sequentially with deionized water containing glass cleaner, acetone, and IPA for 20 minutes each. Subsequently, the cleaned ITO substrate was subjected to UV-ozone treatment for 15 minutes or plasma cleaning for 10 minutes. All subsequent operations were performed in a nitrogen glove box, where the water and oxygen content was less than 0.01 ppm.

[0042] (2) Preparation of hole transport layer SAM (MeO-4PACz)

[0043] Remove the hole transport layer and the mixed solution and ultrasonically disperse them at 30℃-40℃ for 15 minutes for later use. Take 100μL of the mixed solution and drop it onto the surface of the ITO substrate. After standing for 15 seconds, spin coat it at 4000rpm for 30 seconds and anneal it at 100℃ for 8-10 minutes.

[0044] (3) Perovskite layer preparation (PVSK)

[0045] The perovskite precursor and phenothiazine mixture was spin-coated at 1000 rpm for 10 seconds (acceleration 1000 rpm / s), followed by spin-coating at 3000 rpm for 30 seconds (acceleration 3000 rpm / s). At the 30-second mark of the two spin-coating cycles, 150 μL of chlorobenzene was added dropwise to the spinning substrate. The perovskite film was then annealed at 100 °C for 15–20 minutes.

[0046] (4) Electron transport layer fabrication (PCBM)

[0047] The electron transport layer mixed solution PCBM was spin-coated onto the perovskite absorber layer at 1000 rpm for 30 seconds (acceleration 500 rpm / s).

[0048] (5) Metal electrode preparation

[0049] When the pressure is less than 4×10 -4 In the vacuum chamber of Pa A 120 nm thick Ag electrode was thermally evaporated at a deposition rate. All operations were performed in a nitrogen-filled glove box.

[0050] Comparative Example 1:

[0051] The comparative example is basically the same as the scheme of Example 1, except that no phenothiazine was added during the preparation of the hole transport layer, perovskite layer and electron transport layer.

[0052] Comparative Example 2:

[0053] The comparative example is basically the same as the scheme of Example 1, except that phenothiazine was not added during the preparation of the hole transport layer.

[0054] Comparative Example 3:

[0055] This comparative example is basically the same as the scheme of Example 1, except that phenothiazine was not added during the preparation of the perovskite layer. Comparative Example 4:

[0056] This comparative example is basically the same as the scheme of Example 1, except that phenothiazine was not added during the preparation of the electron transport layer.

[0057] Effect Evaluation 1:

[0058] The test characterization section mainly includes current and voltage characteristics:

[0059] The testing method is as follows:

[0060] Current density-voltage (JV) characteristics were measured using a Keithley 2400 source meter under AM 1.5G illumination, with a xenon lamp solar simulator (XES-40S1, SAN-EI) as the light source. Prior to measurement, a standard monocrystalline silicon solar cell with a KG-5 filter was used for calibration to a light intensity of 100 mW / cm². 2 The effective active area of ​​the battery is 0.051 cm². 2 .

[0061] Table 1 Photovoltaic parameters of perovskite solar cells with different passivation layers

[0062]

[0063] Comparative Example 1: The perovskite structure without PTZ addition was used as a benchmark, and all its parameters were lower than those of other improved structures containing PTZ.

[0064] Comparative Example 2: Adding a PTZ to the SAM layer significantly increases the short-circuit current to 25.6 mA / cm². 2 The fill factor was increased to 79.2% and the photoelectric conversion efficiency reached 23.1%, indicating that PTZ can optimize charge extraction and reduce recombination loss in the hole transport layer.

[0065] Comparative Example 3: Adding a PTZ to the PVSK layer increased the open-circuit voltage to 1.15V, the fill factor to 81.7%, and the photoelectric conversion efficiency to 23.2%. This demonstrates that the PTZ can passivate perovskite defects and improve carrier lifetime and interface energy level matching.

[0066] Comparative Example 4: Doping the electron transport layer PCBM with PTZ increased the short-circuit current and fill factor to 24.8 mA / cm². 2 With a photoelectric conversion efficiency of 22.9%, the PTZ (Potential Transformer) achieves 81.1%, reflecting enhanced electron transport efficiency and reduced interface resistance.

[0067] In Example 1, PTZ is integrated as a cover layer into the complete structure SAM+PVSK+PCBM to achieve comprehensive optimization and maximize the synergistic effect of each functional layer.

[0068] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. The application of bulk and interfacial synergistic passivating agents in perovskite solar cells, characterized in that, The bulk and interface synergistic passivating agent is a phenothiazine compound; the perovskite solar cell includes an electrode, an electron transport layer, a perovskite layer, a hole transport layer and a transparent electrode arranged sequentially; the raw materials of the electron transport layer, the perovskite layer and the hole transport layer all include the bulk and interface synergistic passivating agent.

2. The application of the bulk and interface synergistic passivating agent as described in claim 1 in perovskite solar cells, characterized in that, The phenothiazine compounds are phenothiazine, 10-methylphenothiazine, 2-chlorophenothiazine, or 2-acetylphenothiazine.

3. The application of the bulk and interface synergistic passivating agent as described in claim 1 in perovskite solar cells, characterized in that, The electron transport layer in the perovskite solar cell is obtained by spin-coating a mixture of PCBM and phenothiazine in chlorobenzene onto the surface of the perovskite layer.

4. The application of the bulk and interface synergistic passivating agent as described in claim 3 in perovskite solar cells, characterized in that, The mass ratio of PCBM to phenothiazine is 8-12:

1.

5. The application of the bulk and interface synergistic passivating agent as described in claim 1 in perovskite solar cells, characterized in that, The method for preparing the perovskite layer in the perovskite solar cell is as follows: S11: The perovskite precursor solution and phenothiazine are mixed and then spin-coated onto the surface of the hole transport layer in two separate steps. S12: Add chlorobenzene to the mixture after spin coating in step S11, and anneal at 95-105℃ for 15-20 min; The perovskite precursor solution is obtained by adding cesium iodide, formamide iodide (FAI), and lead iodide to a mixed solvent; wherein the mixed solvent is composed of N,N-dimethylformamide and dimethyl sulfoxide in a volume ratio of 3-5:

1.

6. The application of the bulk and interface synergistic passivating agent as described in claim 5 in perovskite solar cells, characterized in that, The solute in the perovskite precursor solution is FA. 0.95 Cs 0.05 PbI3 perovskite, wherein the mass ratio of solute to phenothiazine is 8-12:

1.

7. The application of the bulk and interface synergistic passivating agent as described in claim 1 in perovskite solar cells, characterized in that, The transparent electrode is selected from an ITO conductive glass substrate.

8. The application of the bulk and interface synergistic passivating agent as described in claim 1 in perovskite solar cells, characterized in that, The hole transport layer in the perovskite solar cell is obtained by spin-coating a mixture of [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphoric acid and phenothiazine in anhydrous ethanol onto the surface of a transparent electrode.

9. The application of the bulk and interface synergistic passivating agent as described in claim 8 in perovskite solar cells, characterized in that, The mass ratio of [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphoric acid to phenothiazine is 2-4:

1.

10. The application of the bulk and interface synergistic passivating agent as described in claim 1 in perovskite solar cells, characterized in that, The electrode is selected from metallic Ag electrodes.

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