ITO nanoparticle self-assembled stable trans-perovskite solar cell

Abstract

The invention discloses an ITO (Indium Tin Oxide) nano particle self-assembled stable trans perovskite solar cell, and provides a hydroxyl (-OH) functionalized ITO nano particle (INPs) substrate. The-OH is covalently anchored on the surface of the photoactive nanostructure, so that the covalent immobilization of a self-assembled monolayer (SAM) is realized. In the aspect of shape regulation and control, the introduction of INPs effectively improves the coverage degree of SAM in the trans-perovskite solar cell structure, so that the trans-perovskite solar cell shows excellent solvent resistance in an N, N-dimethylformyl (DMF) polar solvent environment. In the aspect of carrier dynamics regulation and control, the INPs / SAM system not only significantly reduces the interface non-radiative recombination loss, but also greatly improves the interface charge extraction rate and thermal stability. And carrier extraction at the interface of the perovskite solar cell is promoted and interface carrier recombination is inhibited, so that the conversion efficiency and long-term stability of the perovskite solar cell are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of perovskite solar cells, and particularly relates to a substrate-optimized intermediate layer-stable hole transport layer self-assembly to realize a high-efficiency stable transverse perovskite solar cell. ITO nanoparticles are introduced or integrated into the bottom of the hole transport layer interface by using self-assembly technology, so as to form a more stable and more solid composite structure. BACKGROUND

[0002] The hole transport layer SAM monomolecular material forms a firm chemical bond (P-O-In / Sn) with the -OH on the ITO substrate surface through the anchor group phosphate at the molecular end, can form a dense, uniform and pinhole-free ultrathin layer at the atomic scale, greatly reduces the material consumption and interface defects, and the HTL based on the SAM is considered as a revolutionary technology to realize the high-performance and low-cost transverse perovskite solar cell. Although the SAM as the HTL has a broad prospect, it exposes severe challenges in practical application, especially long-term stability. In the subsequent spin-coating process of the perovskite solution (commonly used polar solvents such as DMF), the SAM layer can be partially dissolved or disturbed by these solvents. This will cause local uneven coverage of the SAM layer and form defects. These defects will cause the perovskite to directly contact the ITO, causing serious non-radiative recombination. In addition, the bonding of the SAM and the ITO surface can be hydrolyzed or broken at high temperature (>85°C). Once the anchor bond is broken, the SAM molecules will fall off from the ITO surface, resulting in failure of the hole transport function. The performance of the device will be sharply attenuated in the thermal stress test (such as 85°C continuous heating). Therefore, a novel strategy is urgently needed to stabilize the SAM interface, significantly improve the thermal stability and morphology stability without sacrificing the excellent electrical performance of the SAM. SUMMARY

[0003] Based on this, the purpose of the present application is to stabilize the SAM hole transport layer self-assembly based on the hydroxyl-functionalized ITO nanoparticle substrate, aiming to significantly enhance the mechanical stability and thermal stability without sacrificing the excellent electrical performance of the SAM, so as to greatly improve the long-term operation stability and process robustness of the transverse perovskite solar cell. In view of the key problems such as insufficient morphology stability (weak anti-solvent interference ability) and poor thermal stability (the SAM anchor bond is easy to break at high temperature) of the SAM-based hole transport layer of the transverse perovskite solar cell in the prior art, the present application provides an ITO nanoparticle self-assembly stable transverse perovskite solar cell.

[0004] The specific technical scheme to achieve the purpose of the present application is as follows:

[0005] The application discloses an ITO nanoparticle self-assembly stable reverse perovskite solar cell, which comprises a substrate, a substrate optimization intermediate layer, a hole transport layer, a perovskite thin film layer, an electron transport layer and an electrode layer which are sequentially stacked, wherein the substrate is indium tin oxide (ITO), the substrate optimization intermediate layer is hydroxyl (-OH) functionalized ITO nanoparticles, the hole transport layer is Meo-2PACz, the perovskite thin film layer is perovskite ABX3, the electron transport layer is PCBM, C60 and TPBi, and the electrode layer is an Ag silver electrode; the perovskite ABX3 is composed of 0.05-0.10 inorganic cesium ions Cs + and 0.90-0.95 formamidinium ions FA + , B is a lead ion Pb 2+ , and X is a halogen anion iodine ion I - .

[0006] The substrate ITO nanoparticles are introduced or integrated into the bottom of the hole transport layer interface to form a composite structure; the -OH on the surface of the substrate optimization intermediate layer provides a chemical adsorption site for the phosphate group -PO(OH)2 at the end of the Meo-2PACz molecule, and a firm P-O-Sn covalent bond is formed through a deprotonation condensation reaction, so that a dense and highly ordered self-assembly monolayer is covered.

[0007] The substrate optimization intermediate layer is deposited by a solution spin coating method, the annealing temperature is at most 100 DEG C, and the thickness is 10-20 nm.

[0008] The perovskite solar cell is prepared through the following steps.

[0009] An indium tin oxide substrate is provided.

[0010] A substrate optimization intermediate layer is formed on the substrate.

[0011] A hole transport layer is formed on the substrate optimization intermediate layer.

[0012] A perovskite thin film layer is formed on the hole transport layer.

[0013] An electron transport layer is formed on the perovskite thin film layer.

[0014] An electrode layer is formed on the electron transport layer.

[0015] The formation of each layer specifically comprises the following steps.

[0016] The indium tin oxide substrate is cleaned by using a detergent, deionized water, acetone, isopropanol, and ultrasonic cleaning and ultraviolet ozone (UV-ozone) or oxygen plasma treatment in sequence to increase the surface hydrophilicity and remove organic contaminants; then, the substrate is transferred to a glove box, ITO nanoparticles with a particle size of 5-20 nm are dispersed in isopropanol solvent at a concentration of 0.3-0.5 mg / mL, stirred for 20-30 min, spin-coated on the indium tin oxide substrate at a rotation speed of 3000-4000 rpm, and annealed at 80-100°C for 5-10 min after deposition for 20-30 s to form a uniform substrate optimization intermediate layer;

[0017] Then, a Meo-2PACz solution with a concentration of 1 mg / mL is spin-coated at a rotation speed of 3000-4000 rpm for 20-30 s and annealed at 80-100°C for 5-10 min to form a uniform hole transport layer;

[0018] A, B and X are dissolved in a solvent to obtain a perovskite precursor solution; wherein the molar ratio of A, B and X is 1:1:3; A is inorganic cesium ion Cs + accounting for 0.05-0.10 of the total amount + , B is lead ion Pb 2+ , X is halide anion iodine ion I - , and the solvent is one or a mixture of both of N,N-dimethylformamide DMF and dimethyl sulfoxide DMSO;

[0019] Then, the perovskite precursor solution is spin-coated on the hole transport layer using a spin coater, at a rotation speed of 1500-2000 rpm for 8-10 s, and then at a rotation speed of 4000-5000 rpm for 20-22 s, and 130-150 microliters of chlorobenzene anti-solvent is added at the 10th-13th s, and then annealed on a heating table at 115°C for 30 min to form a perovskite thin film layer;

[0020] Next, a PCBM chlorobenzene solution with a concentration of 5-10 mg / mL is spin-coated on the surface of the perovskite thin film layer using a solution spin coating method, at a rotation speed of 2000-3000 rpm for 40-45 s, and a thickness of 15-20 nm; then, a C60 layer with a thickness of 20-30 nm and a TPBi layer with a thickness of 6-8 nm are sequentially deposited on the PCBM using a vacuum thermal evaporation method to obtain an electron transport layer;

[0021] Finally, a layer of silver is deposited on the electron transport layer as an electrode using a vacuum evaporation method, with a thickness of 80-100 nm.

[0022] The beneficial effects of the present application are:

[0023] 1) Maintaining excellent electrical performance: The ultra-thin and sparse INPs layer does not form a continuous insulating barrier. As it is an n-type semiconductor material itself, the contact with the p-type SAM layer can form a local band bending that is beneficial for hole extraction. Meanwhile, this layer allows the perovskite precursor solution to penetrate and directly contact the SAM layer for nucleation, ensuring the formation of high-quality perovskite thin film and efficient hole injection interface, thus the open-circuit voltage (V oc ) and fill factor (FF) of the device not only do not decay, but even can be optimized due to the improved interface contact.

[0024] 2) Enhanced resistance to solvent erosion: In the anti-solvent quenching step of chlorobenzene after spin-coating the perovskite precursor solution (DMF: DMSO = 4:1), the exposed SAM layer is easily eluted or rearranged by the strong polarity of the anti-solvent, resulting in uneven device performance. In the present invention, the surface INPs act as a physical barrier, effectively dispersing and weakening the impact of the anti-solvent, preventing its direct dissolution and destruction of the underlying SAM molecules, significantly improving the process window and repeatability.

[0025] 3) Improved thermal stability: The chemical anchoring bond between conventional SAM molecules and metal oxide substrates (such as the P-O-M bond between the phosphate group and the In / Sn-OH surface of ITO) is prone to hydrolytic rupture at high temperatures (> 85°C). In the present invention, INPs form additional interactions with the functional groups (such as carboxyl, amine, etc.) at the end of the SAM molecules through their surface -OH groups, forming a "multi-point anchoring" and "cross-linking" effect. This greatly stabilizes the overall connection of the SAM molecules to the substrate, inhibits molecular desorption at high temperatures, allowing the device to withstand more stringent heat treatment and environmental temperature fluctuations. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 Schematic diagram of the present invention for inserting ITO nanoparticle-enhanced SAM desorption from the substrate and its strengthening mechanism;

[0027] Figure 2 20 nm scale transmission electron microscopy (TEM) observation diagram of INPs particle size and substrate coverage, Fourier transform infrared spectroscopy (FTIR) of ITO and INPs, and O 1s nuclear energy level XPS spectra of ITO and ITO / INPs before and after DMF flushing;

[0028] Figure 3 P 2p and Sn 4s nuclear energy level XPS spectra of SAM layer and INPs / SAM layer on ITO substrate before and after DMF flushing, P / Sn ratio, and SAM and INPs / SAM surface potential (KPFM) image;

[0029] Figure 4Fig. 6 is a schematic diagram of P 2p and Sn 4s core level XPS spectra and P / Sn ratio of buried interface of SAM and INPs / SAM before and after thermal aging;

[0030] Figure 5 Fig. 7 is a schematic diagram of PL spectra of PVK, SAM / PVK and INPs / SAM / PVK, TRPL spectra of SAM / PVK and INPs / SAM / PVK, TPC spectra of SAM and INPs / SAM before and after thermal aging, and impedance spectroscopy (EIS) analysis of SAM and INPs / SAM perovskite solar cells before and after thermal aging in dark conditions;

[0031] Figure 6 Fig. 8 is a schematic diagram of a device structure of an inverted structure perovskite solar cell, J-V curves, steady-state maximum power point output, V oc vs. light intensity relationship, V oc efficiency PCE statistical distribution, device thermal stability under N2 atmosphere at 85°C, and maximum power point tracking (MPPT) stability evaluation of SAM and INPs / SAM-based devices under continuous LED illumination at 85°C. DETAILED DESCRIPTION

[0032] The perovskite solar cell and the preparation process thereof provided by the present application will be further described below in combination with the accompanying drawings and examples.

[0033] Referring to Figure 1 , the ITO nanoparticles provided by the present application include a well-crystallized nanocrystalline core and isopropanol solvent molecules dispersed around, aiming to optimize and stabilize the upper hole transport material MeO-2PACz, and finally improve the performance and stability of the perovskite solar cell. The average particle size of the nanocrystalline core is distributed in the range of 5-20 nm, and the excellent crystallinity thereof ensures that the final thin film has high conductivity and light transmittance. The ITO nanoparticles rich in -OH groups enhance the adsorption performance of the self-assembled monolayer of MeO-2PACz, and avoid unnecessary heterocontact with the ITO substrate. The -OH groups on the surface of the INPs not only provide sufficient adsorption sites for MeO-2PACz, but also significantly enhance the binding strength thereof.

[0034] The perovskite type ABX3, A is inorganic cesium ion Cs + accounting for 0.05, and formamidinium ion FA + accounting for 0.95, B is lead ion Pb 2+ , X is halogen anion iodine ion I -The band gap is 1.48-1.53 eV, which has the highest theoretical efficiency of the perovskite battery, and therefore, the perovskite material is further preferably Cs 0.05 FA 0.95 PbI3.

[0035] The perovskite solar cell provided by the application comprises a substrate, a substrate optimization intermediate layer, a hole transport layer, a perovskite thin film layer, an electron transport layer and a metal electrode layer which are sequentially stacked.

[0036] The hole transport layer is Meo-2PACz, and the thickness is 5-20 nm. Considering that the hole transport layer has a certain light absorption capacity, the thickness is preferably 15 nm.

[0037] The perovskite thin film layer has a thickness of 400-600 nm. Considering that a higher thickness of the perovskite layer causes a larger carrier bulk recombination, and a lower thickness causes less light absorption of the perovskite layer, the thickness is preferably 500 nm.

[0038] The electron transport layer comprises a PCBM layer, a C60 layer and a TPBi layer which are sequentially stacked. Considering that the perovskite has a large energy level loss with C60, PCBM and C60 are used to transport electrons, and TPBi is used to block holes. The thickness of the PCBM layer is 20-40 nm, the thickness of the C60 layer is 30-45 nm, and the thickness of the TPBi layer is 6-10 nm. The total thickness of the electron transport layer is 50-100 nm. Because PCBM is easily soluble in chlorobenzene, and chlorobenzene has no destructive effect on the perovskite, chlorobenzene is selected as the solvent, and a solution spin coating method is used for preparation, which can effectively cover the possible holes on the surface of the perovskite. The thickness is preferably 20 nm. The C60 and TPBi layers are prepared by a thermal evaporation vacuum plating method, which can ensure that the thin film is more dense and uniform, and the thicknesses are preferably 30 nm and 6 nm, respectively.

[0039] The thickness of the electrode layer is 80-100 nm, and the material is not limited. However, considering the conductivity and work function of the metal, the electrode is preferably an Ag electrode, and the thickness is preferably 100 nm.

[0040] In the following, the preparation method of the perovskite solar cell will be further described through specific examples.

[0041] Example

[0042] The perovskite solar cell of the example comprises a substrate, a substrate optimization intermediate layer, a hole transport layer, a perovskite thin film layer, an electron transport layer and a metal electrode layer which are sequentially stacked, and the preparation method is as follows:

[0043] Using a 2cm × 2cm ITO substrate as the base, the substrate was sequentially cleaned with detergent, distilled water, acetone, and isopropanol. After cleaning, the substrate was dried with nitrogen and then subjected to ozone ultraviolet treatment in air for 20 minutes.

[0044] The substrate was then transferred to a glove box, where well-crystallized INPs (5-20 nm) were spin-coated and annealed to form a nanostructured conductive layer on an ITO glass substrate. Subsequently, a Meo-2PACz hole transport layer solution was spin-coated onto the surface and annealed again to form a uniformly covered organic functional film.

[0045] 1.5M Cs 0.05 FA 0.95 PbI3 was dissolved in DMF:DMSO = 4:1 to obtain a perovskite precursor solution; wherein, the inorganic ion Csium ion constituted 0.05%. + The proportion of formamidinium ions (FA) was 0.95. + B represents lead ions (Pb). 2+ X is a halide anion, iodide ion, I. - The solvent is a mixture of two of N,N-dimethylformamide and dimethyl sulfoxide;

[0046] Then, the perovskite precursor solution was spin-coated onto the deposited Meo-2PACz substrate using a spin coater at a speed of 2000 rpm for 10 s and then 4000 rpm for 20 s. At the 13th s, 150 μL of chlorobenzene antisolvent was dropped in, and then the substrate was annealed at 115 °C for 30 minutes to form a perovskite thin film layer.

[0047] The perovskite film was then passivated by depositing a 0.5 mg / ml PDAI2 solution onto it using a spin-coating method at 3000 rpm for 30 s, followed by annealing at 100 °C for 5 minutes.

[0048] The specific method for fabricating an electron transport layer on a perovskite thin film is as follows:

[0049] First, a 10 mg / mL PCBM chlorobenzene solution was spin-coated onto the perovskite film surface using a solution spin-coating method at a speed of 2000 rpm for 45 s, resulting in a thickness of 20 nm. Then, a 30 nm thick C60 layer and a 6 nm thick TPBi layer were sequentially deposited on the PCBM using a vacuum thermal evaporation method.

[0050] A layer of silver with a thickness of 100 nm was deposited on the electron transport layer using a vacuum evaporation method as an electrode.

[0051] See Figure 1, the connection between the underlying substrate and the hole transport layer is strengthened by nanostructure design and surface chemistry regulation. The abundant -OH on the surface of INPs provides a large number of ideal chemical adsorption sites for the phosphate groups (-PO(OH)2) at the end of Meo-2PACz molecules, achieving a more dense and firm SAM coverage. This layer of INPs as a functional spacer layer avoids the problem of uneven adsorption or weak binding of Meo-2PACz with the underlying dense ITO substrate. This improves the energy level alignment and charge transfer at the interface, significantly improving the efficiency of hole extraction from the perovskite layer to the electrode and reducing charge recombination. This strong binding force can effectively resist the flushing and peeling effects during subsequent solution processing, preventing the SAM layer from falling off. More importantly, it can inhibit the desorption of SAM molecules during the long-term operation and aging of the device, which is an extremely important factor in improving the service life of the device. Figure 1 Path (i) in FIG. 1 shows that the self-assembled monolayer forms a relatively dense arrangement on the substrate surface. However, under harsh conditions such as polar solvent erosion or 85°C thermal aging, most self-assembled monolayers are prone to fall off from the substrate surface, causing irreversible damage to the device. Path (ii) shows that the introduction of hydroxyl-rich ITO nanoparticles under the self-assembled monolayer enhances the binding sites and improves the surface binding force, making the self-assembled monolayer more evenly distributed on the substrate surface. This structure not only effectively resists the flushing and peeling effects during subsequent solvent processing, but more importantly, it can inhibit the desorption of SAM during the long-term aging of the device, thereby significantly improving the service life of the device.

[0052] Referring to Figure 2 FIG. 1 is a schematic diagram of the device structure, and FIG. 2 is a schematic diagram of the device structure with INPs as a functional spacer layer. FIG. 3 is a 20 nm scale TEM observation diagram of the particle size and substrate coverage of INPs, FTIR spectra of ITO and INPs, and O 1s nuclear energy level XPS spectra of ITO and ITO / INPs before and after DMF flushing. Figure 2 a Transmission electron microscopy (TEM) shows that the size of INPs is uniform, with a particle size of ~40 nm. Figure 2 b FTIR shows that INPs are rich in -OH groups, which can be used as adsorption sites for SAM. Figure 2 c-2f XPS data shows that the O 1s peak at 529.83 eV is from lattice oxygen, and the peak at 532.10 eV corresponds to adsorbed hydroxyl groups. After the control group ITO substrate is flushed with DMF, the -OH oxygen element ratio drops from 13.52% to 8.09%, indicating that -OH desorption is severe. In the ITO / INPs composite substrate, -OH forms a strong bonding structure on the surface of INPs, which is resistant to solvent flushing, so the oxygen element ratio only decreases slightly from 14.37% to 13.92% after DMF flushing.

[0053] Referring to Figure 3XPS spectra and P / Sn ratios of the P 2p and Sn 4s nuclear levels in the SAM and INPs / SAM layers on ITO substrates before and after DMF washing, as well as KPFM images of the surface potentials of SAM and INPs / SAM. In the ITO / SAM system ( Figure 3 In (ab), the most significant change after DMF rinsing is the substantial enhancement of the Sn XPS signal at 139.10 eV, which should be attributed to the ITO exposure effect caused by the desorption of MeO-2PACz. However, in the ITO / INPs / SAM system, MeO-2PACz is firmly bound to the INPs surface and does not desorb. Therefore, the tin XPS signal remains almost unchanged after DMF rinsing. Figure 3 (c, d). The P / Sn elemental ratio further confirms the severe desorption phenomenon in the ITO / SAM system after DMF cleaning. For example... Figure 2 As shown in e-2f, the P / Sn ratio decreased significantly from 2.97% to 2.48% after cleaning, indicating significant SAM desorption. In contrast, the ITO / INPs / SAM system only decreased slightly from 3.11% to 2.95%. Furthermore, KPFM measurements showed that the surface potential of ITO / SAM fluctuated drastically from ~315 mV to ~420 mV after DMF rinsing. Figure 2 (g, h), which should be due to the partial desorption of SAM from the ITO substrate. The surface potential of the ITO / INPs / SAM system remained stable after DMF rinsing without significant change, further demonstrating that INPs can enhance the binding strength between SAM and the ITO substrate, thereby inhibiting its desorption.

[0054] See Figure 4 XPS spectra and P / In ratios of the P 2p and Sn 4s nuclear levels at the buried interface before and after thermal aging of SAM and INPs / SAM were analyzed. Long-term thermal aging leads to secondary desorption of MeO-2PACz after solvent washing. XPS analysis of the buried interface reveals the mechanism of enhanced thermal stability of perovskite solar cell materials. Figure 4 As shown in a and 4b, the Sn 4s signal at the ITO / MeO-2PACz bottom interface, at 138.46 eV, significantly increased after thermal aging, indicating that heating caused secondary desorption of SAM, resulting in uneven coverage. In contrast, the Sn signal of the ITO / INPs / MeO-2PACz system remained at a low level after aging, indicating that the enhanced -OH groups hardly desorbed from MeO-2PACz. Figure 4 (c-4d). The P / Sn elemental ratio further confirms that severe desorption occurred in ITO / MeO-2PACz during the aging process. Figure 4As shown in e and 4f, after thermal aging, the P / Sn ratio decreased significantly from 2.16% to 0.93%, indicating that a large amount of SAM desorption occurred. In contrast, the P / Sn ratio of the ITO / INPs / SAM system only decreased slightly from 3.12% to 2.78%, demonstrating excellent thermal stability.

[0055] Figure 5 PL spectra of PVK, SAM / PVK, and INPs / SAM / PVK, TRPL spectra of SAM / PVK and INPs / SAM / PVK, TPC spectra of SAM and INPs / SAM measured before and after thermal aging, and EIS analysis of INPs / SAM perovskite solar cells before and after thermal aging; PL and TRPL were used to study the carrier transfer process between ITO / SAM and perovskite thin films. Figure 5 As shown in figure a, compared to the ITO / SAM substrate, the perovskite on the ITO / INPs / SAM substrate exhibits a stronger photoluminescence quenching phenomenon, indicating a significant improvement in its hole transfer efficiency. This phenomenon can be attributed to the suppression of surface SAM desorption during the perovskite coating formation process. The TRPL data of the perovskite were fitted using a double exponential function, where the first lifetime (τ1) corresponds to interfacial carrier transfer, and the second lifetime (τ2) is related to bulk recombination. Figure 5 As shown in b, the τ1 value of the perovskite on the ITO / INPs / SAM substrate (96.50 ns) is significantly shorter than that on the ITO / SAM substrate (187.56 ns), indicating that the hole transfer rate from the perovskite to the ITO / INPs / SAM substrate is faster. Transient photocurrent and electrochemical impedance spectroscopy were used to study the carrier transport behavior in perovskite solar cells during device aging. Figure 5 As shown in cd, in the ITO / SAM perovskite solar cell, the TPC lifetime increases significantly from 0.64 μs to 1.18 μs after device aging, indicating a decrease in interfacial carrier transfer performance, which should be caused by SAM desorption. In contrast, in the ITO / INPs / SAM perovskite solar cell, the TPC lifetime only changes slightly from 0.58 μs to 0.62 μs, indicating stable interfacial carrier transfer performance. Furthermore, EIS results show ( Figure 5 ITO / INPs / SAM devices exhibit superior electrical performance, including higher recombination resistance (Ref). rec and lower series resistance (R) s ). After aging, its R rec It only decreased from 115 kΩ to 109 kΩ, while R s The RΩ then increases from 0.15 kΩ to 0.18 kΩ. In comparison, the RΩ of ITO / SAM devices after aging... rec It decreased significantly to 54 kΩ, while Rs The resistance increased from 0.26 kΩ to 0.43 kΩ. This performance degradation is attributed to the desorption of the SAM layer after aging.

[0056] See Figure 6 This is a schematic diagram of an inverted perovskite solar cell device, showing the JV curves, steady-state maximum power point output, and V of the SAM and INPs / SAM devices. oc Relationship with light intensity, V oc The statistical distribution of PCE, the thermal stability of the device under N2 atmosphere heating at 85°C, and the maximum power point tracking operational stability of SAM and INPs / SAM-based devices under continuous LED illumination at 85°C are compared. Figure 6 a. The inverted perovskite solar cell was constructed using glass-ITO / INPs / Meo-2PACz / perovskite / PDAI2 / C 60 / TPBi / Ag structure. The ITO / INPs / SAM perovskite solar cell exhibits the highest efficiency of 26.44%, with a voltage V oc The current density is 1.189 V, and the current density is J. sc 26.18 mA cm -1 The fill factor FF is 84.94% ( Figure 6 (b) This is significantly higher than the efficiency of the ITO / SAM control group perovskite solar cells (25.07%). For example... Figure 6 As shown in c, its stable power output reaches 26.36%, higher than that of ITO / SAM devices (25.04%). V oc The light intensity dependence indicates that the perovskite solar cell containing INPs has a lower ideality factor (n=1.06) compared to the SAM-based device (n=1.19), further demonstrating the suppression effect of interfacial recombination in the ITO / INPs / SAM perovskite solar cell. Figure 6 d). Figure 6 e and 6f demonstrate the V of 20 individual devices. oc and PCE distribution. Devices based on ITO / INPs / SAM have an average V ocSignificant improvements were observed in both efficiency (from 1.179 V to 1.188 V) and PCE (from 24.60% to 26.20%). Besides efficiency, stability is also a crucial factor for perovskite solar cells. Due to the ease of SAM desorption, ITO / SAM perovskite solar cells typically experience severe degradation during device aging. The stability of perovskite solar cells under thermal and operating conditions was evaluated. In the 85°C thermal stability test, the unencapsulated ITO / INPs / SAM device maintained 96.19% of its initial PCE after 1300 hours of thermal aging at 85°C, while the ITO / SAM device degraded significantly faster, retaining only 54.84% of its PCE under the same conditions. Figure 6 g). In operational stability testing, the perovskite solar cells were measured using a simulated LED light source with maximum power point tracking (MPPT) at an ambient temperature of 85°C. The ITO / INPs / SAM-based perovskite solar cells maintained an initial photoelectric conversion efficiency of 96.76% after 1000 hours of continuous operation, significantly outperforming devices containing only SAM (retention rate 77.51%, see [link]). Figure 6 h) demonstrates a remarkable improvement in thermal stability.

Claims

1. A self-assembled, stable inverse perovskite solar cell using ITO nanoparticles, characterized in that, The perovskite solar cell comprises: a substrate, a substrate-optimized intermediate layer, a hole transport layer, a perovskite thin film layer, an electron transport layer, and an electrode layer stacked sequentially. The substrate is indium tin oxide (ITO), the substrate-optimized intermediate layer is hydroxyl (-OH)-functionalized ITO nanoparticles, the hole transport layer is Meo-2PACz, the perovskite thin film layer is perovskite-type ABX3, the electron transport layer is PCBM, C60, and TPBi, and the electrode layer is an Ag silver electrode. In the perovskite-type ABX3, A is cesium ions (Cs) with a concentration of 0.05-0.10%. + and formamidinium ions (FA) at a concentration of 0.90-0.95%. + B represents lead ions (Pb). 2+ X is a halide anion, iodide ion, I. - ; Substrate ITO nanoparticles are introduced or integrated into the bottom of the hole transport layer interface to form a composite structure; the -OH on the surface of the substrate optimized intermediate layer provides chemisorption sites for the phosphate group -PO(OH)2 at the end of the Meo-2PACz molecule, and a strong PO-Sn covalent bond is formed through deprotonation condensation reaction, thereby achieving a dense and ordered self-assembled monolayer coverage; The substrate-optimized intermediate layer is deposited using a solution spin coating method, with an annealing temperature of up to 100 ℃ and a thickness of 10-20 nm.

2. The perovskite solar cell according to claim 1, characterized in that, Its preparation specifically includes the following steps: Provide indium tin oxide substrate; A substrate-optimized intermediate layer is formed on the substrate; and A hole transport layer is formed on the optimized intermediate layer of the substrate; and A perovskite thin film layer is formed on the hole transport layer; and An electron transport layer is formed on the perovskite thin film layer; and An electrode layer is formed on the electron transport layer; wherein, The formation of each layer specifically includes: The indium tin oxide (ITO) substrate was cleaned by sequentially ultrasonic cleaning with detergent, deionized water, acetone, and isopropanol, followed by ultraviolet ozone or oxygen plasma treatment to increase surface hydrophilicity and remove organic contaminants. Then, it was transferred to a glove box, where ITO nanoparticles with a diameter of 5-20 nm were dispersed in isopropanol solvent at a concentration of 0.3-0.5 mg / mL and stirred for 20-30 min. The mixture was then spin-coated onto the ITO substrate at a speed of 3000-4000 rpm. After deposition for 20-30 s, it was annealed at 80-100°C for 5-10 min to form a uniform substrate-optimized intermediate layer. Subsequently, a Meo-2PACz solution with a concentration of 1 mg / mL was spin-coated at a speed of 3000-4000 rpm for 20-30 s and annealed at 80-100°C for 5-10 minutes to form a uniformly covered hole transport layer. A, B, and X were dissolved in a solvent to obtain a perovskite precursor solution; wherein the molar ratio of A, B, and X was 1:1:3; and A was cesium ions (Cs) comprising 0.05-0.10% of the total content. + The proportion of formamidinium ions (FA) is 0.90-0.95%. + B represents lead ions (Pb). 2+ X is a halide anion, iodide ion, I. - The solvent is one or a mixture of two of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO); Then, the perovskite precursor solution was spin-coated onto the hole transport layer using a spin coater. The spin speed was 1500-2000 rpm for 8-10 s, then 4000-5000 rpm for 20-22 s. At the 10-13 s mark, 130-150 μL of chlorobenzene anti-solvent was added dropwise. The mixture was then annealed at 115°C for 30 minutes to form a perovskite thin film layer. Next, a 5-10 mg / mL PCBM chlorobenzene solution was spin-coated onto the surface of the perovskite thin film using a solution spin-coating method at a speed of 2000-3000 rpm for 40-45 s, resulting in a thickness of 15-20 nm. Then, a C60 layer with a thickness of 20-30 nm and a TPBi layer with a thickness of 6-8 nm were sequentially deposited on the PCBM using a vacuum thermal evaporation method to obtain the electron transport layer. Finally, a layer of silver with a thickness of 80-100 nm was deposited on the electron transport layer using vacuum evaporation as an electrode.

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