Preparation method and application of expanded pi-conjugated metal naphthyanine derivative

Abstract

The invention discloses a preparation method and application of an expanded pi-conjugated metal naphthyanine derivative, and belongs to the technical field of organic photoelectric materials. The naphthyanine derivative can be used as a hole transport material to be applied to a perovskite solar cell. The metal naphthyanine derivative is a planar macrocyclic aromatic compound and has a high pi-conjugation characteristic. By introducing alkenyl or alkynyl to the periphery of the naphthyanine ring, a pi-conjugated system of the molecule can be further extended, so that the charge transport property is improved. Besides, the solubility, hydrophobicity, film-forming property and other properties of the material can be regulated and controlled by changing the type and number of substituent groups on double-bond or triple-bond carbon atoms, so that the requirement of the metal naphthyanine derivative as a hole transport material is met. The hole mobility and the thermal stability of the naphthyanine derivative are far higher than those of original Spiro-OMeTAD. When the naphthalocyanine nickel hole transport material taking alkenyl as a peripheral substituent group is applied to a perovskite solar cell, the photoelectric conversion efficiency greater than 24% is obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of organic photoelectric materials, and in particular relates to a preparation method of an extended π-conjugated metal naphthalocyanine derivative and an application thereof in a perovskite solar cell. Background Art

[0002] As the global demand for clean energy continues to rise, the development of solar cell technology has become a key direction in the photovoltaic field. Among the many solar cell technologies, perovskite solar cells have received unprecedented attention due to their excellent light absorption ability, long carrier diffusion length, high defect tolerance and excellent solution processability. Since its discovery in 2009, through the unremitting efforts of researchers, its photoelectric conversion efficiency has been greatly improved from 3.8% to 27.0%, showing an efficiency comparable to that of crystalline silicon solar cells, and its development prospects are extremely broad.

[0003] The hole transport layer is a key component of perovskite solar cells, which is mainly responsible for extracting and transporting photogenerated holes, blocking the electron transport path, inhibiting charge recombination at the interface, and acting as a protective barrier to resist water and oxygen invasion. Therefore, choosing suitable hole transport materials (HTMs) is the key to achieving efficient and stable perovskite solar cells.

[0004] To date, 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)-amino]-9,9'-spirobifluorene (Spiro-OMeTAD) has been widely used as standard HTMs in high-performance formal perovskite solar cells. Due to the low intrinsic conductivity and hole mobility of Spiro-OMeTAD, lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and 4-tert-butylpyridine (tBP) dopants need to be introduced to improve conductivity and film forming properties. However, the hygroscopicity of LiTFSI will accelerate the degradation of perovskite; the volatility of tBP will cause irreversible damage to the film morphology. In addition, the glass transition temperature of Spiro-OMeTAD is low ( T g =120 °C), which causes strain and crystallization at high temperatures, leading to film cracking or pinholes, which harms battery efficiency and life. Summary of the invention

[0005] In order to solve the problems existing in the prior art, the present invention aims to provide a preparation method and application of an extended π-conjugated metal naphthalocyanine derivative. The metal naphthalocyanine derivative provided by the present invention has simple synthesis and purification steps, good hole transport performance, T gWhen metal naphthalocyanine derivatives are used as HTMs in perovskite solar cells, only a small amount of dopants need to be introduced to achieve high efficiency, which can effectively make up for the shortcomings of Spiro-OMeTAD in device applications.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions: An extended π-conjugated metal naphthalocyanine derivative, wherein the structure of the naphthalocyanine derivative is shown in Formula I:

[0007] In formula I, the substituent Q is or ; The naphthalocyanine derivative is tetrasubstituted or octasubstituted; Among them, R 1 -R 4 are independently selected from hydrogen, alkyl, alkenyl, aryl, ester or cyano; M is hydrogen or a metal selected from nickel, copper, zinc, cobalt, palladium, iron, calcium, magnesium, lead, tin, strontium, barium, manganese, lithium, sodium, potassium, platinum, titanium, ruthenium, aluminum, indium, vanadium or gallium.

[0008] The structure of the naphthalocyanine derivative is shown in Formula II or Formula III:

[0009] Among them, R 1 -R 4 are independently selected from hydrogen, alkyl, alkenyl, aryl, ester or cyano; M is hydrogen or a metal selected from nickel, copper, zinc, cobalt, palladium, iron, calcium, magnesium, lead, tin, strontium, barium, manganese, lithium, sodium, potassium, platinum, titanium, ruthenium, aluminum, indium, vanadium or gallium.

[0010] Furthermore, the R 1 -R 4 is an alkyl group; M is a metal, and the metal is selected from nickel, copper, zinc, cobalt, and iron.

[0011] The structure of the naphthalocyanine derivative is shown in Formula IV:

[0012] Wherein: n is 1-16; M is hydrogen or a metal, and the metal is selected from nickel, copper, zinc, cobalt, palladium, iron, calcium, magnesium, lead, tin, strontium, barium, manganese, lithium, sodium, potassium, platinum, titanium, ruthenium, aluminum, indium, vanadium or gallium.

[0013] Furthermore, M is a metal selected from nickel, copper, zinc, cobalt and iron.

[0014] Specifically, the structure of the naphthalocyanine derivative is:

[0015] An application of an extended π-conjugated metal naphthalocyanine derivative, wherein the naphthalocyanine derivative is applied in a perovskite solar cell.

[0016] A perovskite solar cell comprises the above-mentioned metal naphthalocyanine derivative.

[0017] Furthermore, the perovskite solar cell structure is a planar formal structure, which comprises, from bottom to top, a transparent conductive substrate, an electron transport layer, a perovskite light absorption layer, a hole transport layer, and a metal electrode.

[0018] Furthermore, the metal naphthalocyanine derivative is applied as a hole transport layer in a perovskite solar cell.

[0019] Furthermore, a two-dimensional perovskite intermediate layer is coated between the perovskite light absorption layer and the hole transport layer.

[0020] After phthalocyanine is linearly extended to form naphthalocyanine, the π-conjugation degree of the system is greatly improved, which increases the planarity of the molecule and effectively enhances the intermolecular interaction. The increase in the conjugated skeleton will also lead to greater orbital overlap, which is beneficial to charge transfer. On the basis of the naphthalocyanine ring, the introduction of long-chain alkenyl groups can, on the one hand, further extend the π-conjugated system, well regulate the intermolecular interaction and the stacking behavior of molecules in the film state, and improve the charge transport properties; on the other hand, the presence of long alkyl chains can also improve the solubility of the material and help form a flat film through solution deposition.

[0021] The present invention also provides a method for preparing the extended π-conjugated metal naphthalocyanine derivatives described in the above technical solution, the structural formulas of which are shown in Formula II and Formula III:

[0022] In Formula II and Formula III, R 1 -R 4 is hydrogen, alkyl, alkenyl, aryl, ester or cyano. The naphthalocyanine derivative may be tetra-substituted or octa-substituted.

[0023] In formula II and formula III, M is hydrogen or a metal, which may be nickel, copper, zinc, cobalt, palladium, iron, calcium, magnesium, lead, tin, strontium, barium, manganese, lithium, sodium, potassium, platinum, titanium, ruthenium, aluminum, indium, vanadium or gallium.

[0024] The reaction formula is as follows:

[0025] The specific steps are: (1) Halogenation reaction: Under light conditions and the action of benzoyl peroxide (BPO) as an initiator, o-phthalic acid derivatives react withN -Bromosuccinimide (NBS) in carbon tetrachloride (CCl 4 ) solvent to undergo bromination reaction. Wherein, the initiator may also be azobisisobutyronitrile; X is a halogen, such as chlorine, bromine, or iodine.

[0026] (2) Diels-Alder reaction: Under heating conditions, the halogenated o-phthalic acid derivative reacts with trans-butylene dinitrile to form a ring, and potassium iodide is added to increase the reaction activity.

[0027] (3) Heck reaction: Under the protection of inert gas, the above products are coupled with olefins in the presence of strong base and palladium catalyst. 1 -R 4 It is hydrogen, alkyl, alkenyl, aryl, ester or cyano. Active Pd (0) is generally generated in situ by the reaction of Pd (II) catalyst with the corresponding ligand. Commonly used palladium catalysts include Pd (OAc) 2 、Pd(PPh 3 ) 4 、Pd(dppf)Cl 2 etc.; the ligands include tri(o-methylphenyl)phosphine, di-tert-butylneopentylphosphine, trineopentylphosphine, etc. The bases that can be used in the reaction are: triethylamine, potassium carbonate, potassium acetate, etc. The solvent is usually selected N , N -Dimethylformamide (DMF), acetonitrile, tetrahydrofuran, etc. Note: In order to maintain the activity of the palladium catalyst, the reaction must be carried out in an oxygen-free environment.

[0028] (4) Synthesis of alkenyl-substituted naphthalocyanine derivatives: Under the protection of inert gas, with 1,8-diazabicyclo[5,4,0]undec-7-ene (DBU) as a catalyst, the above products react with the corresponding metal salts (metal acetates or metal chlorides) in a high boiling point solvent (n-pentanol, n-hexanol, anhydrous quinoline or nitrobenzene) to produce metal naphthalocyanine derivatives. During the reaction, special attention should be paid to maintaining anhydrous and oxygen-free conditions.

[0029]

[0030] The synthesis steps of alkynyl-substituted naphthalocyanine derivatives are similar to those described above, but based on the reaction conditions described in step (3), it is necessary to add Cu (Ⅰ) halide (CuI or CuBr) as a co-catalyst to enhance the reaction activity so that the reaction can be carried out under mild conditions.

[0031] The present invention also applies the metal naphthalocyanine derivatives to perovskite solar cells. The device structure is a planar formal structure, which includes a transparent conductive substrate, an electron transport layer, a perovskite light absorption layer, a hole transport layer, and a metal electrode from bottom to top.

[0032] The transparent conductive substrate includes fluorine-doped tin oxide (FTO) and indium tin oxide (ITO). The electron transport layer includes titanium oxide (TiO 2 ) or tin oxide (SnO 2 ). The general formula of perovskite is ABX 3 , where A represents a carbamate cation, a methylamine cation, a cesium ion, etc.; B represents a transition metal cation such as a lead ion, a tin ion, etc.; and X represents a halogen anion. The hole transport layer is a metal naphthalocyanine derivative provided by the present invention, which needs to be dissolved in an organic solvent, such as 1,2-dichlorobenzene or chlorobenzene, and after being stirred evenly, a small amount of LiTFSI and tBP dopants are added, and finally the solution is coated on the surface of the perovskite. The electrode is a gold electrode. Note that in order to effectively block electron backflow and reduce non-radiative recombination, the present invention introduces a two-dimensional perovskite intermediate layer between the three-dimensional perovskite layer and the hole transport layer.

[0033] The beneficial effects of the present invention are as follows: metal naphthalocyanine derivatives, as a planar macrocyclic aromatic compound, exhibit a high degree of π-conjugation as a whole. The characteristics of the naphthalocyanine derivatives are: on the basis of the naphthalocyanine ring, alkenyl or alkynyl groups are introduced to expand the π-conjugation degree of the system, thereby improving the charge transport properties. Metal naphthalocyanine derivatives have abundant modifiable sites. Alkyl, alkenyl, aryl, ester or cyano groups are further introduced on double-bonded or triple-bonded carbon atoms to adjust the solubility, hydrophobicity, film-forming properties, carrier extraction and transport capabilities, defect passivation capabilities, etc. of the material.

[0034] This naphthalocyanine nickel derivative has many advantages: first, its synthesis and purification are relatively easy and can be completed under simple laboratory conditions. Second, thanks to the further extension of π-conjugation, the material exhibits excellent hole transport performance and thermal stability. Its hole mobility can reach 3.92 ´ 10 -4 cm 2 V -1 s -1 , much higher than the original Spiro-OMeTAD (1.89 ´ 10 - 5 cm 2 V -1 s -1 ); Material T g It can reach 167 °C, which is higher than 120 °C of Spiro-OMeTAD. T g The morphological stability of naphthalenecyanine films under thermal stress can be significantly improved. Finally, thanks to the introduction of long-chain alkenyl groups, the material exhibits good solubility in organic solvents, which greatly reduces the difficulty of solution preparation.

[0035] Based on the above advantages, naphthalocyanine derivatives are applied as HTMs in perovskite solar cells. During preparation, only a small amount of dopant needs to be introduced into the corresponding solution to achieve high efficiency of the device. The photovoltaic parameters of the best device are: photoelectric conversion efficiency (PCE) is 24.34%, open circuit voltage ( V oc ) is 1.16 V, the short-circuit current density ( J sc ) is 25.65 mAcm -2 , the filling factor (FF) is 81.60%. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 UV-visible absorption spectra of Hexenyl-NiNc and Octenyl-NiNc in 1,2-dichlorobenzene and thin film states.

[0037] Figure 2 This is the hole mobility test diagram of Hexenyl-NiNc and Octenyl-NiNc.

[0038] Figure 3 The differential scanning calorimetry (DSC) test curves of Hexenyl-NiNc and Octenyl-NiNc.

[0039] Figure 4 This is a cross-sectional electron microscope image of a perovskite solar cell using Hexenyl-NiNc as the hole transport material.

[0040] Figure 5 Energy level diagram of each layer of material in the device.

[0041] Figure 6 is the current-voltage of perovskite solar cells with Hexenyl-NiNc, Octenyl-NiNc and Spiro-OMeTAD as hole transport materials ( J - V )curve. DETAILED DESCRIPTION

[0042] Next, a method for preparing an extended π-conjugated metal naphthalocyanine derivative and its application will be described in detail through specific examples and drawings. The implementation and protection of the present invention are not limited to this, and all technologies covered by the present invention are within the scope of protection. It is worth noting that people familiar with this art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The reagents and instruments used in the example description can be obtained through commercial channels.

[0043] Example 1 The present invention provides two extended π-conjugated metal naphthalocyanine derivatives, hexenyl and octenyl substituted naphthalocyanine nickel (Hexenyl-NiNc and Octenyl-NiNc):

[0044] The specific synthesis steps are as follows:

[0045] (1) Synthesis of intermediate 1: 4-bromo-1,2-dimethylbenzene (4.60 g, 0.025 mol), NBS (17.8 g, 0.1 mol), BPO (0.1 g) and CCl 4 (50 mL) was placed in a 250 mL single-necked flask. Under light conditions, heat to reflux at 80 °C for 12 h. After the reaction was completed, the insoluble NBS was filtered out and the filtrate was collected. After vacuum concentration, a yellow solid was obtained, and n-hexane was added in small amounts and multiple times for washing until the solid was white. After dissolving the solid with a small amount of dichloromethane, it was extracted with a saturated sodium sulfite solution and dried with anhydrous sodium sulfate to obtain a white solid (7.81 g, yield 62.3%). 1 H NMR (400 MHz, DMSO- d 6 ): d 7.92 (s, 1H), 7.75 (t, 2H), 7.69 (d, 2H).

[0046]

[0047] (2) Synthesis of intermediate 2: Intermediate 1 (3.96 g, 0.008 mol), trans-butene dinitrile (0.62 g, 0.008 mol), potassium iodide (7.97 g, 0.048 mol) and 50 mL of DMF were placed in a 250 mL single-necked flask and heated under reflux at 80 °C for 12 h. After the reaction was completed, the reaction solution was cooled to room temperature and then 200 mL of cold water was added. Suspended matter precipitated. Saturated Na 2 SO 3 The solution was stirred until the suspension turned light yellow. After vacuum filtration, the filter cake was repeatedly washed with hot water and deionized water, and dried to obtain a light yellow solid (1.53 g, yield 74.7%). 1 H NMR (400 MHz, DMSO- d 6 ): d8.89 (s, 1H), 8.80 (s, 1H), 8.48 (d, 1H), 8.13 (d, 1H), 8.04 (dd, 1H).

[0048]

[0049] (3) Synthesis of intermediate 3: A mixture of intermediate 2 (1 g, 3.98 mmol), palladium acetate (8.7 mg, 1 mol %), and tri(o-methylphenyl)phosphine (47.4 mg, 4 mol %) was dissolved in 20 mL of DMF. The flask was briefly evacuated and replaced with nitrogen three times. 1-Hexene (0.60 mL, 4.86 mmol) and triethylamine (0.68 mL, 4.86 mmol) were then added. The reaction mixture was heated to reflux at 100 °C for 12 h. After the reaction was completed, the reaction solution was cooled to room temperature and the Pd (0) precipitate was removed by filtration. The filtrate was poured into a solution consisting of ethyl acetate (100 mL), deionized water (100 mL), and aqueous hydrochloric acid (10 mL) and stirred for 10 min. The organic phase was then separated by extraction, and the aqueous phase was further extracted with ethyl acetate (2 ´ 50 mL), and the organic layer was washed with water (2 ´ 100 mL) and saturated sodium chloride solution (100 mL), and dried over anhydrous sodium sulfate. The crude product obtained after vacuum concentration was further purified by silica gel column chromatography (petroleum ether / ethyl acetate = 10 / 1, V / V) to obtain a white solid (0.72 g, yield 71.2%). 1 H NMR (400 MHz, DMSO- d 6 ) d 8.82-8.67 (m, 2H), 8.14-7.96 (m, 3H), 6.64 (dq, 2H), 2.28 (q, 2H), 1.52-1.43 (m, 2H), 1.36 (h, 2H), 0.91 (t, 3H).

[0050]

[0051] (4) Synthesis of intermediate 4: Similar to the synthesis of intermediate 3, only 1-hexene was replaced by 1-octene. A white solid (0.81 g, 72.3%) was obtained. 1 H NMR (400 MHz, DMSO- d 6 ) d8.79-8.69 (m, 2H), 8.05 (dd, 3H), 6.63 (d, 2H), 2.30-2.22 (m, 2H), 1.48 (p, 2H), 1.36-1.25 (m, 6H), 0.87 (t, 3H).

[0052]

[0053] (5) Synthesis of the target compound Hexenyl-NiNc: Intermediate 3 (0.60 g, 2.32 mmol), anhydrous nickel chloride (0.10 g, 0.77 mmol), DBU (0.2 mL), and n-hexanol (5 mL) were mixed together in N 2 atmosphere, heated to reflux at 160 °C for 12 h. After the reaction was completed, the reaction mixture was cooled to room temperature, 50 mL of methanol was added to precipitate the product, and the suspension was ultrasonicated for 5 min. It was then filtered and the filter cake was washed with hydrochloric acid aqueous solution, hot water, and deionized water in sequence. The dried crude product was separated and purified by a neutral alumina column to obtain a green solid powder (0.20 g, yield 23.7%). MALDI-TOF-MS C 72 H 64 N 8 Ni[M] + Theoretical calculated value: m / z 1098.46, Measured value: m / z 1098.46.

[0054]

[0055] (6) Synthesis of the target compound Octenyl-NiNc: The synthesis steps were the same as above. Finally, a black solid powder (0.23 g, 24.7%) was obtained. MALDI-TOF-MS C 80 H 80 N 8 Ni[M] + Theoretical calculated value: m / z 1210.59, Measured value: m / z 1210.59.

[0056] Figure 1The UV-visible absorption spectra of Hexenyl-NiNc and Octenyl-NiNc in 1,2-dichlorobenzene and solid films. Both materials show a unique Q-band absorption between 550 and 750 nm, which can be explained as pp* excitation between bonding and antibonding molecular orbitals. Compared with the solution state, the Q bands of the solid films of both materials are widely broadened, indicating that they have strong molecular stacking in the film, which is conducive to the extraction and transport of holes. Due to the Davydov effect, the Q band splits, which also shows that both materials have strong hole mobility.

[0057] Figure 2 The hole mobility test graphs of Hexenyl-NiNc and Octenyl-NiNc. The high hole mobility of hole transport materials is conducive to the transfer of hole carriers from the perovskite layer to the counter electrode, which is crucial for providing efficient and stable devices. Thanks to the tighter intermolecular stacking caused by the extension of the π-conjugated system, Hexenyl-NiNc and Octenyl-NiNc both exhibit excellent hole transport performance, with hole mobilities of 3.92 ´ 10 -4 cm 2 V -1 s -1 , 3.27´ 10 -4 cm 2 V -1 s -1 Obviously, the hole mobility of the former is higher. And the hole mobility of both is much higher than that of the original Spiro-OMeTAD (1.89 ´ 10 -5 cm 2 V -1 s -1 ), and there are even orders of magnitude differences.

[0058] The thermal stability of Hexenyl-NiNc and Octenyl-NiNc was evaluated by DSC. Figure 3 As shown. T g They are 167 °C and 160 °C, respectively, which are higher than Spiro-OMeTAD (120 °C) and especially Hexenyl-NiNc. T g Higher naphthalenecyanine materials will exhibit a more durable morphology under thermal stress, and will also slow down the penetration of diffusible substances in the perovskite and the environment, effectively inhibiting the degradation of the perovskite.

[0059] Example 2 Next, Hexenyl-NiNc and Octenyl-NiNc were applied as HTMs to perovskite solar cells. The device structure of the cell is: FTO / SnO 2 / FAPB 3 / (BA) 2 MAPb 2 I 7 / HTMs / Au.

[0060] The specific preparation process is: (1) Place the FTO substrate in a polytetrafluoroethylene holder and ultrasonically clean it in sequence using deionized water containing detergent, ultrapure water, acetone, and anhydrous ethanol. Ultrasonic cleaning is performed for more than 30 min with each solvent to make the substrate clean and free of stains. After drying, the substrate is subjected to ozone UV surface treatment for 20 min.

[0061] (2) Preparation of SnO by chemical bath deposition 2 The chemical bath solution consists of stannous chloride dihydrate (137.5 mg), urea (625 mg), thioglycolic acid (12.5 mL), concentrated hydrochloric acid (625 mL) and deionized water (50 mL). FTO was placed in the pre-configured solution, heated to 90 °C in an oil bath, and the reaction was stopped after the temperature was kept constant for 4 h. After removal, it was ultrasonically cleaned with deionized water and isopropanol, and annealed on a heating table at 170 °C for 1 h.

[0062] (3) PbI 2 (1.53 M), FAI (1.4 M), MACl (0.5 M) and MAPbBr 3 (0.0122 M) was dissolved in 1 mL of a mixed solvent consisting of DMF and dimethyl sulfoxide (DMSO) (volume ratio of 8:1) to prepare a perovskite precursor solution. 40 mL of the perovskite solution was added dropwise onto the FTO / SnO 2 The film was formed by spin coating on the substrate. The first stage was spun at 2000 rpm for 10 s, and the second stage was spun at 6000 rpm for 30 s. At the 10th s of the second stage, 200 mL of anti-solvent chlorobenzene was quickly and evenly added to the center of the substrate. After the spin coating process was completed, the substrate was transferred to a hot plate at 100 °C for annealing for 1 h, and the perovskite light absorbing layer was prepared.

[0063] (4) Two-dimensional perovskite (BA) 2 MAPb 2 I 7 (15 mg) was dissolved in 1 mL of acetonitrile and stirred overnight without heating to obtain a two-dimensional perovskite precursor solution. After the perovskite film cooled to room temperature, 60 The 2D perovskite precursor solution was spin-coated on the perovskite film (spin coating speed: 4000 rpm min -1 After the spin coating process was completed, the substrate was transferred to a hot plate at 80 °C for annealing for 5 min to obtain a two-dimensional perovskite layer.

[0064] (5) Dissolve 30 mg of Hexenyl-NiNc and 30 mg of Octenyl-NiNc in 1 mL of 1,2-dichlorobenzene and stir until completely dissolved. Then add 15 LiTFSI solution (concentration: 170 mg mL -1 ; solvent: acetonitrile), 15 Take the above prepared solution and drop it on the center of the substrate (30 ), and then spin-coated at 3000 rpm for 30 s to obtain the hole transport layer.

[0065] (6) A gold electrode was deposited on the hole transport layer by vacuum evaporation with a thickness of 100 nm.

[0066] Comparative Example 1 Spiro-OMeTAD is used as HTMs to prepare perovskite solar cells. The device structure is: FTO / SnO 2 / FAPB 3 / (BA) 2 MAPb 2 I 7 / Spiro-OMeTAD / Au. Except for the hole transport layer, the preparation methods of the other functional layers are as described in Example 2. The preparation process of the Spiro-OMeTAD hole transport layer is as follows: 90 mg of Spiro-OMeTAD is dissolved in 1 mL of chlorobenzene and stirred until completely dissolved. Then 23 LiTFSI solution (concentration: 520 mg mL -1 ; solvent: acetonitrile), 39.5 mL of tBP, 10 mL of Co(Ⅲ)-TFSI (concentration: 375 mg mL -1 ; solvent: acetonitrile), stir to mix evenly. Take 30 mL of the above solution and add it to the center of the substrate, spin-coat it at 3000 rpm for 30 s to form a film, and obtain the Spiro-OMeTAD hole transport layer.

[0067] Figure 4This is a cross-sectional electron microscope image of the device, which clearly shows that the functional layers are well connected and the thin films are uniformly and completely covered. In addition, the perovskite grains are large and arranged vertically, which is conducive to the rapid transmission of charges.

[0068] Figure 5 Compared with FAPbI 3 , (BA) 2 MAPb 2 I 7 The valence band maximum of the two-dimensional perovskite has a better match with the highest occupied molecular orbital energy level of HTMs, which is beneficial to the extraction and transport of holes. 2 MAPb 2 I 7 The more negative conduction band minimum can effectively block the electrons from flowing back from the perovskite to the gold electrode, reducing the charge recombination loss at the interface and improving the overall efficiency of the device.

[0069] The perovskite solar cells prepared in Example 2 and Comparative Example 1 were tested using a digital source meter (Keithley 2420). J - V The curve results are as follows Figure 6 The test conditions are: AM 1.5 G light (100 mW cm -2 ). The PCE of the Hexenyl-NiNc device is 24.34%. V oc is 1.16 V, J sc 25.65 mA cm -2 , FF is 81.60%. In contrast, the photovoltaic parameters of the corresponding device of Octenyl-NiNc all show lower values, and the PCE of the battery is 23.47%. V oc is 1.15V, J sc 25.28 mA cm -2 , FF is 80.41%. Hexenyl-NiNc devices show higher performance than Spiro-OMeTAD devices (PCE: 24.17%). However, the spin coating concentration of Hexenyl-NiNc as a hole transport layer is only 30 mg mL -1 , which is much lower than the dosage of Spiro-OMeTAD (90 mg mL -1). It is worth noting that the content of LiTFSI and tBP introduced in Hexenyl-NiNc is also much lower than that in Spiro-OMeTAD, which can reduce the degree of damage to the film morphology under harsh conditions to improve the stability of the device. The low preparation amount and low dopant content significantly reduce the manufacturing cost of the device, which is conducive to the preparation of large-area components for commercialization in the future.

[0070] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments may still be modified, or some or all of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An extended π-conjugated metal naphthalocyanine derivative, characterized in that: The structure of the naphthalocyanine derivative is shown in the following formula I: ； In formula I, the substituent Q is or ; The naphthalocyanine derivative is tetrasubstituted or octasubstituted; Wherein, R1-R4 are independently selected from hydrogen, alkyl, alkenyl, aryl, ester or cyano; M is hydrogen or a metal selected from nickel, copper, zinc, cobalt, palladium, iron, calcium, magnesium, lead, tin, strontium, barium, manganese, lithium, sodium, potassium, platinum, titanium, ruthenium, aluminum, indium, vanadium or gallium.

2. An extended π-conjugated metal naphthalocyanine derivative according to claim 1, characterized in that: The structure of the naphthalocyanine derivative is shown in Formula II or Formula III: ； Wherein, R1-R4 are independently selected from hydrogen, alkyl, alkenyl, aryl, ester or cyano; M is hydrogen or a metal selected from nickel, copper, zinc, cobalt, palladium, iron, calcium, magnesium, lead, tin, strontium, barium, manganese, lithium, sodium, potassium, platinum, titanium, ruthenium, aluminum, indium, vanadium or gallium.

3. The extended π-conjugated metal naphthalocyanine derivative according to claim 2, characterized in that: The R1-R4 are alkyl groups; M is a metal, and the metal is selected from nickel, copper, zinc, cobalt, and iron.

4. The extended π-conjugated metal naphthalocyanine derivative according to claim 2, characterized in that: The structure of the naphthalocyanine derivative is shown in Formula IV: ； Wherein: n is 1-16; M is hydrogen or a metal, and the metal is selected from nickel, copper, zinc, cobalt, palladium, iron, calcium, magnesium, lead, tin, strontium, barium, manganese, lithium, sodium, potassium, platinum, titanium, ruthenium, aluminum, indium, vanadium or gallium.

5. The extended π-conjugated metal naphthalocyanine derivative according to claim 4, characterized in that: The M is a metal, and the metal is selected from nickel, copper, zinc, cobalt, and iron.

6. The use of an extended π-conjugated metal naphthalocyanine derivative according to any one of claims 1 to 4, characterized in that: The naphthalocyanine derivative is applied in perovskite solar cells.

7. A perovskite solar cell, characterized in that: The battery comprises the naphthalocyanine derivative according to any one of claims 1 to 4.

8. A perovskite solar cell according to claim 7, characterized in that: The perovskite solar cell structure is a planar formal structure, which includes a transparent conductive substrate, an electron transport layer, a perovskite light absorption layer, a hole transport layer, and a metal electrode from bottom to top.

9. A perovskite solar cell according to claim 8, characterized in that: The naphthalocyanine derivative is applied to a hole transport layer.

10. A perovskite solar cell according to claim 9, characterized in that: A two-dimensional perovskite intermediate layer is coated between the perovskite light absorption layer and the hole transport layer.

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