Preparation method and application of perovskite solar cell with copper phthalocyanine carbon dots as hole transport layer

Abstract

The application discloses a preparation method of a perovskite solar cell with phthalocyanine copper carbon dots as a hole transport layer and application thereof. The preparation method comprises the following steps: taking one end of a conductive substrate as a negative electrode; preparing an electron transport layer on the rest part of the conductive substrate, then depositing a perovskite absorption layer, coating a phthalocyanine copper carbon dot dispersion solution, annealing to obtain a phthalocyanine copper carbon dot hole transport layer, finally, coating a carbon paste and heating and drying to obtain the perovskite solar cell. The insoluble macrocyclic molecule phthalocyanine copper is treated by using a hydrothermal method, so that the solubilization and carbonization processes are combined, the carbon dots are synthesized from bottom to top, the phthalocyanine copper carbon dot hole transport layer is prepared from a solution and does not contain a dopant, the phthalocyanine copper carbon dot hole transport layer is applied to the perovskite solar cell, and the cell efficiency is as high as 13%. The application breaks the bottleneck that insoluble organic matters cannot be used as a hole transport layer in a solution processing perovskite solar cell, improves the optical performance and thermal stability of the perovskite solar cell, and reduces the manufacturing cost.

Description

Technical Field

[0001] This invention belongs to the field of solar cell material technology, specifically relating to a method for preparing and applying a perovskite solar cell with copper phthalocyanine carbon dots as the hole transport layer. Background Technology

[0002] Solution-processable perovskite solar cells (PSCs) have shown great promise as competitive, low-cost solar cells, offering the advantages of high efficiency and ease of fabrication, and have thus demonstrated great potential to rival traditional inorganic cells. The power conversion efficiency (PCE) of perovskite solar cells has rapidly increased from 3.8% in 2009 to 25.5% in 2021. As the efficiency of perovskite solar cells approaches their theoretical limits, pathways to improve their overall performance are receiving close attention. In particular, there has been renewed interest in organic small molecule hole transport materials (HTMs) other than spiro-OMeTAD. Commercialization may be problematic due to the long synthesis and purification times and high costs. Although numerous studies have attempted to replace spiro-OMeTAD, almost all reported HTMs are designed with triphenylamine (TPA) as the end-capping group. For large-scale applications, the cost of these hole transport layers is prohibitively high, and the inherent quality of the organic components is clearly a detrimental factor affecting the long-term operation and thermal stability of PSCs. Therefore, developing alternative, more stable, and more cost-effective high-temperature superconducting materials is a challenging task and has become one of the hot topics in perovskite solar cell research. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a method for preparing and applying a perovskite solar cell with copper phthalocyanine carbon dots as the hole transport layer.

[0004] The method for preparing a perovskite solar cell with copper phthalocyanine carbon dots as the hole transport layer according to the present invention is as follows: one end of the conductive substrate is left blank as the negative electrode; an electron transport layer is first prepared in the remaining part, then a perovskite absorber layer is deposited, then a copper phthalocyanine carbon dot dispersion is coated, and the mixture is annealed at 90-110℃ for 5-20 minutes to obtain the copper phthalocyanine carbon dot hole transport layer. Finally, carbon paste is coated and heated to dry to obtain the perovskite solar cell.

[0005] The preparation method of the copper phthalocyanine carbon dot dispersion is as follows: 30-75 mg of copper phthalocyanine is dissolved in 20-30 mL of ethanol, and then the mixture is subjected to hydrothermal reaction at 180-240 °C for 8-18 h; after cooling to room temperature, large particle precipitates are removed by filtration through a 0.22 μm membrane, and the filtrate is vacuum dried to obtain copper phthalocyanine carbon dot powder; then it is dispersed in chlorobenzene at a dispersion concentration of 0.10-0.60 mg / mL.

[0006] The copper phthalocyanine carbon dot dispersion was coated by spin coating at 1000-3000 rpm for 10-30 seconds.

[0007] The steps for preparing the electron transport layer are as follows: first, spin-coat a tetraisopropoxide titanium ethanol solution, heat and dry at 100-150℃ to obtain a barrier layer; then spin-coat a mesoporous TiO2 ethanol dispersion, and sinter at 400-600℃ for 10-60 min.

[0008] The deposition method of the perovskite absorber layer is as follows: PbI2 and MAI are added to DMF and DMSO to prepare a perovskite precursor solution, which is then spin-coated onto the electron transport layer. Chlorobenzene is added dropwise during the spin-coating process, and finally the solution is heated and dried.

[0009] This invention employs a hydrothermal method to treat insoluble macrocyclic copper phthalocyanine, combining solubilization and carbonization processes to synthesize carbon dots from the bottom up. A hole transport layer of copper phthalocyanine carbon dots is then prepared from a solution without dopants. When applied to perovskite solar cells, this method achieves a cell efficiency of up to 13%. This invention overcomes the bottleneck of using insoluble organic materials as hole transport layers in solution-processed perovskite solar cells, improving the optical performance and thermal stability of perovskite solar cells while reducing manufacturing costs. Attached Figure Description

[0010] Figure 1 This is an HRTEM image of the sample under the conditions of Example 1 of the present invention.

[0011] Figure 2 The image shows the XRD pattern of the sample under the conditions described in Example 1 of this invention.

[0012] Figure 3 This is a Raman image of the sample under the conditions of Example 1 of the present invention.

[0013] Figure 4 The images shown are SEM images of the PVK / Cu-Pc-CDs film under the conditions of Example 1 of the present invention. Figure (A) shows the PVK / Cu-Pc-CDs film, and Figure (B) shows the PVK film.

[0014] Figure 5 The image shows the steady-state photoluminescence spectrum of the PVK / Cu-Pc-CDs thin film under the conditions of Example 1 of this invention. The solid line represents the PVK / Cu-Pc-CDs thin film, and the dashed line represents the PVK thin film.

[0015] Figure 6 The image shows the time-resolved photoluminescence spectrum of the PVK / Cu-Pc-CDs thin film under the conditions of Example 1 of this invention. The square represents the PVK / Cu-Pc-CDs thin film, and the triangle (dashed line) represents the PVK thin film.

[0016] Figure 7The image shows the electrochemical impedance spectroscopy (EIS) diagrams of Cu-Pc-CDs under the conditions of Example 1 of this invention. Squares represent Cu-Pc-CDs PIS, and triangles (dashed lines) represent PIS.

[0017] Figure 8 The image shows the ultraviolet absorption spectrum of the PVK / Cu-Pc-CDs film under the conditions of Example 1 of this invention. The solid line represents the PVK / Cu-Pc-CDs film, and the dashed line represents the PVK film.

[0018] Figure 9 Different light intensities (40-100 mW / cm²) under the conditions of Example 1 of the present invention. 2 The open-circuit voltage and short-circuit current density are function curves.

[0019] Figure 10 C of Cu-Pc-CDs under the conditions of Example 1 of this invention 1s High-resolution XPS spectrum.

[0020] Figure 11 The figures show the contact angles of the PVK / Cu-Pc-CDs thin film under the conditions of Example 1 of the present invention. Figure (A) shows the PVK / Cu-Pc-CDs thin film, and Figure (B) shows the PVK thin film.

[0021] Figure 12 The JV curve of PSCs of Cu-Pc-CDs under the conditions of Embodiment 1 of the present invention is shown. Detailed Implementation

[0022] Example 1

[0023] (1) Transparent conductive substrate: The substrate is selected from FTO conductive glass. The FTO glass substrate is ultrasonically cleaned in detergent, deionized water, isopropanol and anhydrous ethanol for 15 min in sequence.

[0024] (2) Electron transport layer: One end of a clean FTO glass slide is blank as the negative electrode; the remaining part is first coated with a barrier TiO2 layer with a 0.4M tetraisopropoxide titanium ethanol solution, spin-coated at 1000 rpm for 3 s, then spin-coated at 2500 rpm for 30 s, and then heated at 125℃ for 5 min; then spin-coated with an ethanol dispersion of mesoporous TiO2 (TiO2 and ethanol mass ratio 1:3.5), spin-coated at 1000 rpm for 3 s, then spin-coated at 3500 rpm for 30 s, and finally sintered at 500℃ for 30 min;

[0025] (3) Perovskite absorber layer: 0.461 g PbI2 and 0.159 g MAI were dissolved in 0.72 mL DMF and 0.072 mL DMSO to prepare a perovskite precursor solution. Then, the solution was spin-coated at 1000 rpm for 10 s, 200 μL of chlorobenzene was added, and then the solution was spin-coated at 4000 rpm for 20 s to deposit the perovskite film on the mesoporous TiO2 layer. Finally, the solution was heated at 100 °C for 10 min.

[0026] (4) Hole transport layer:

[0027] a. Preparation of copper phthalocyanine carbon dots: 75 mg of copper phthalocyanine was dissolved in 30 mL of ethanol, and then these solutions were reacted in a stainless steel autoclave equipped with polytetrafluoroethylene at 200 °C for 12 h; after cooling to room temperature, large particles were removed by filtration through a 0.22 μm membrane, and Cu-Pc-CDs powder was obtained by vacuum drying at 60 °C.

[0028] b. Disperse Cu-Pc-CDs (0.20 mg / mL) in chlorobenzene, spin-coat the resulting solution onto the perovskite absorber layer at 3000 rpm for 20 s, and finally anneal at 100 °C for 5 minutes to obtain the copper phthalocyanine carbon point hole transport layer.

[0029] (5) Carbon paste is coated onto the hole transport layer as a carbon electrode and heated at 100°C for 30 min to obtain a perovskite solar cell.

[0030] The hole transport layer obtained in step (4) was tested to demonstrate the formation of copper phthalocyanine carbon dots. Figure 1 HRTEM images show clear lattice fringes and lattice spacing of copper phthalocyanine carbon dots. Figure 2 The broad peak at 2θ = 25°, as shown by the XRD pattern, is attributed to the disordered graphite structure. Figure 3 Raman spectroscopy revealed at 1359 cm⁻¹ -1 The D band at the sp3 defect of the C atom and at 1596 cm⁻¹ -1 The G-band at the sp2 defect of the C atom proves the formation of carbon dots in copper phthalocyanine. Figure 4 The SEM image of the PVK / Cu-Pc-CDs thin film shows Cu-Pc-CDs aggregated on the surface of the film.

[0031] Depend on Figure 5 Steady-state photoluminescence spectra show that the fluorescence intensity of the PVK / Cu-Pc-CDs film is significantly reduced compared to the PVK film, indicating that the copper phthalocyanine carbon dots have a strong hole extraction capability for effective charge transfer from PVK to Cu-Pc-CDs. Figure 6Time-resolved photoluminescence spectroscopy reveals that the PVK / Cu-Pc-CDs film possesses two lifetimes: τ1 = 0.3 ns and τ2 = 27.4 ns. The shorter decay component can be attributed to charge transfer from PVK to the hole transport layer quencher and nonradiative charge recombination within the PVK layer; the longer decay component can be attributed to radiative recombination of trapped charges. In contrast, the τ1 and τ2 of the PVK film are 0.6 ns and 74.3 ns, respectively. The shortened τ1 and τ2 of the PVK / Cu-Pc-CDs film further clearly demonstrate more efficient hole transfer and extraction from PVK to Cu-Pc-CDs. Figure 7 The EIS plots of the PSCs of Cu-Pc-CDs and the control PSC show that the Rs and Rrec of the control PSCs are 65.1 Ω and 175.9 Ω, respectively. In contrast, the PSCs with Cu-Pc-CDs have a smaller Rs (49.9 Ω) and a larger Rrec (502.8 Ω), indicating better carrier transport and effective suppression of charge recombination. Figure 8 The UV absorption spectra of the PVK / Cu-Pc-CDs film and the PVK film show that the curves basically overlap, indicating that the absorption of the PVK film is not affected after modification with Cu-Pc-CDs.

[0032] Figure 9 Different light intensities (40-100mW / cm) 2 The open-circuit voltage and short-circuit current density function curves show that, from the relationship between ln(Jsc) and [ln(I)], the slope value of PSCs with Cu-Pc-CDs (0.954) is closer to 1 than that of control PSCs (0.944), indicating that the lower PVK layer undergoes bimolecular recombination at the Cu-Pc-CDs interface. A graph of Voc as a function of [ln(I)] was linearly fitted to evaluate the slope, which represents the recombination process caused by the trap states in the PSCs. For PSCs with Cu-Pc-CDs and control PSCs, the slopes of the fitted curves were 1.07 and 1.12 kBT / q, respectively, indicating that the energy loss of trap-assisted recombination in PSCs with Cu-Pc-CDs is small. Figure 10 The high-resolution XPS spectra of C1s in Cu-Pc-CDs show that the C1s of Cu-Pc-CDs... 1s The core energy level consists of two parts: the peak at 284.81 eV is attributed to C C / C = C, and the peak at 288.53 eV is attributed to C = N / C = O (it should be noted that the Cu-Pc molecular structure does not contain the O element). Figure 11The contact angle of PVK / Cu-Pc-CDs shows that, compared with PVK film (76.3°), PVK / Cu-Pc-CDs film exhibits a larger water contact angle of 97.3°, indicating enhanced hydrophobicity and good humidity stability. Figure 12 The photovoltaic parameters and current density-voltage (JV) curves of the best-performing PSCs with Cu-Pc-CDs and the control PSCs show that the PCE of the PSCs with Cu-Pc-CDs is 13.78%, while the PCE of the control PSCs is only 12.55%.

[0033] Table 1. Photovoltaic performance of Cu-Pc-CDs solar cells prepared under the conditions of Example 1.

[0034]

[0035] Example 2

[0036] (1) Transparent conductive substrate: The substrate is selected from FTO conductive glass. The FTO glass substrate is ultrasonically cleaned in detergent, deionized water, isopropanol and anhydrous ethanol for 15 min in sequence.

[0037] (2) Electron transport layer: One end of a clean FTO glass slide is blank as the negative electrode; the remaining part is first coated with a barrier TiO2 layer with a 0.4M tetraisopropoxide titanium ethanol solution, spin-coated at 1000 rpm for 3 s, then spin-coated at 2500 rpm for 30 s, and then heated at 125℃ for 5 min; then spin-coated with an ethanol dispersion of mesoporous TiO2 (TiO2 and ethanol mass ratio 1:3.5), spin-coated at 1000 rpm for 3 s, then spin-coated at 3500 rpm for 30 s, and finally sintered at 500℃ for 30 min;

[0038] (3) Perovskite absorber layer: 0.461 g PbI2 and 0.159 g MAI were dissolved in 0.72 mL DMF and 0.072 mL DMSO to prepare a perovskite precursor solution. Then, the solution was spin-coated at 1000 rpm for 10 s, 200 μL of chlorobenzene was added, and then the solution was spin-coated at 4000 rpm for 20 s to deposit the perovskite film on the mesoporous TiO2 layer. Finally, the solution was heated at 100 °C for 10 min.

[0039] (4) Hole transport layer:

[0040] a. Preparation of copper phthalocyanine carbon dots: 30 mg of copper phthalocyanine was dissolved in 20 mL of ethanol, and then these solutions were reacted in a stainless steel autoclave equipped with polytetrafluoroethylene at 180 °C for 8 h; after cooling to room temperature, large particles were removed by filtration through a 0.22 μm membrane, and Cu-Pc-CDs powder was obtained by vacuum drying at 60 °C.

[0041] b. Disperse Cu-Pc-CDs (0.40 mg / mL) in chlorobenzene, spin-coat the resulting solution onto the perovskite absorber layer at 1000 rpm for 10 s, and finally anneal at 100 °C for 5 minutes to obtain the copper phthalocyanine carbon point hole transport layer.

[0042] (5) Carbon paste is coated onto the hole transport layer as a carbon electrode and heated at 100°C for 30 min to obtain a perovskite solar cell.

[0043] Example 3

[0044] (1) Transparent conductive substrate: The substrate is selected from FTO conductive glass. The FTO glass substrate is ultrasonically cleaned in detergent, deionized water, isopropanol and anhydrous ethanol for 15 min in sequence.

[0045] (2) Electron transport layer: One end of a clean FTO glass slide is blank as the negative electrode; the remaining part is first coated with a barrier TiO2 layer with a 0.4M tetraisopropoxide titanium ethanol solution, spin-coated at 1000 rpm for 3 s, then spin-coated at 2500 rpm for 30 s, and then heated at 125℃ for 5 min; then spin-coated with an ethanol dispersion of mesoporous TiO2 (TiO2 and ethanol mass ratio 1:3.5), spin-coated at 1000 rpm for 3 s, then spin-coated at 3500 rpm for 30 s, and finally sintered at 500℃ for 30 min;

[0046] (3) Perovskite absorber layer: 0.461 g PbI2 and 0.159 g MAI were dissolved in 0.72 mL DMF and 0.072 mL DMSO to prepare a perovskite precursor solution. Then, the solution was spin-coated at 1000 rpm for 10 s, 200 μL of chlorobenzene was added, and then the solution was spin-coated at 4000 rpm for 20 s to deposit the perovskite film on the mesoporous TiO2 layer. Finally, the solution was heated at 100 °C for 10 min.

[0047] (4) Hole transport layer:

[0048] a. Preparation of copper phthalocyanine carbon dots: 50 mg of copper phthalocyanine was dissolved in 25 mL of ethanol, and then these solutions were reacted in a stainless steel autoclave equipped with polytetrafluoroethylene at 240 °C for 18 h; after cooling to room temperature, large particles were removed by filtration through a 0.22 μm membrane, and Cu-Pc-CDs powder was obtained by vacuum drying at 60 °C.

[0049] b. Disperse Cu-Pc-CDs (0.60 mg / mL) in chlorobenzene, spin-coat the resulting solution onto the perovskite absorber layer at 2000 rpm for 30 s, and finally anneal at 100 °C for 5 minutes to obtain the copper phthalocyanine carbon point hole transport layer.

[0050] (5) Carbon paste is coated onto the hole transport layer as a carbon electrode and heated at 100°C for 30 min to obtain a perovskite solar cell.

Claims

1. A method for fabricating a perovskite solar cell with copper phthalocyanine carbon dots as the hole transport layer, characterized in that, The specific operation of the preparation method is as follows: one end of the conductive substrate is blank as the negative electrode; the remaining part first prepares an electron transport layer, then deposits a perovskite absorber layer, then coats a copper phthalocyanine carbon dot dispersion, annealing at 90-110 ℃ for 5-20 minutes to obtain a copper phthalocyanine carbon dot hole transport layer, and finally coats a carbon paste and heats and dries it to obtain a perovskite solar cell. The preparation method of the copper phthalocyanine carbon dot dispersion is as follows: 30-75 mg of copper phthalocyanine is dissolved in 20-30 mL of ethanol, and then the mixture is subjected to hydrothermal reaction at 180-240℃ for 8-18 h; after cooling to room temperature, large particle precipitates are removed by filtration through a 0.22 μm membrane, and the filtrate is vacuum dried to obtain copper phthalocyanine carbon dot powder; then it is dispersed in chlorobenzene at a dispersion concentration of 0.10-0.60 mg / mL.

2. The preparation method according to claim 1, characterized in that, The copper phthalocyanine carbon dot dispersion was coated by spin coating at 1000-3000 rpm for 10-30 s.

3. The preparation method according to claim 1, characterized in that, The steps for preparing the electron transport layer are as follows: first, spin-coat a tetraisopropoxide titanium ethanol solution, heat and dry at 100-150℃ to obtain a barrier layer; then spin-coat a mesoporous TiO2 ethanol dispersion, and sinter at 400-600℃ for 10-60 min.

4. The preparation method according to claim 1, characterized in that, The deposition method of the perovskite absorber layer is as follows: PbI2 and MAI are added to DMF and DMSO to prepare a perovskite precursor solution, which is then spin-coated onto the electron transport layer. Chlorobenzene is added dropwise during the spin-coating process, and finally the solution is heated and dried.

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