Application of an interfacial molecule with multifunctional active sites

Abstract

The present invention belongs to the technical field of solar cells, and specifically relates to the application of an interfacial molecule with multifunctional active sites. To solve the problem of relatively single action sites of passivation molecules, the interfacial molecule of the present invention is a compound containing at least three groups among S, -C=O, -NH2, N, O, and F. The interfacial molecule is spin-coated on the perovskite layer, thereby effectively reducing the film defects of the perovskite layer, increasing the average carrier lifetime of the perovskite film, reducing the interfacial recombination loss of the device, simultaneously reducing the roughness of the perovskite film, improving the energy level arrangement of the device, thus increasing the power conversion efficiency of the solar device. At the same time, the humidity stability and lead leakage of the device have also been significantly improved, promoting the large-scale and commercialization process of perovskite solar cells.

Description

Technical Field

[0001] The invention belongs to the technical field of solar cells, and in particular relates to the application of an interface molecule with multifunctional active sites. Background Art

[0002] In recent years, organic-inorganic hybrid metal halide perovskite solar cells (PSCs) have been attracting attention due to their advantages such as simple preparation, low cost, adjustable band gap, and high molar absorption. At the same time, PSCs are considered to be the most likely new solar energy materials to replace silicon. Now, single-junction PSCs have achieved a power conversion efficiency (PCE) of 25.7%. However, due to its rapid crystallization, a large number of defects are generated, resulting in an increase in non-radiative recombination, which is very unfavorable for achieving high PCE and high stability of PSCs. Therefore, there is an urgent need to develop new organic molecules to reduce interfacial recombination and thus improve the efficiency of perovskite solar cells.

[0003] Patent CN202011077876.8 introduces a perovskite solar cell with an interface modification layer. This method can only passivate the defects of the perovskite film, and the action site of the passivation molecule is relatively single. Such molecules with single-site passivation are everywhere, so this work still has great limitations. At present, it is urgent to find interface modification molecules with multi-site passivation. Summary of the invention

[0004] In view of the above problems, the present invention provides an interface molecule with multi-active site passivation for modifying lead-based perovskite solar cells.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] Application of an interfacial molecule with multifunctional active sites as a modifying molecule in lead-based perovskite solar cell devices.

[0007] Furthermore, the interface molecule is a compound containing at least three groups of S, -C=O, -NH2, N, O and F at the same time.

[0008] Further, the structural formula of the interface molecule is as follows:

[0009]

[0010] Furthermore, the structure of the lead-based perovskite solar cell device is a formal structure or a trans structure.

[0011] Furthermore, the modified molecules are spin-coated between the perovskite layer and the electron transport layer or the hole transport layer of the lead-based perovskite solar cell device.

[0012] Furthermore, the concentration of the modification molecule is 0.1 mg / mL to 25 mg / mL, and after spin coating, it is annealed at a temperature of 25°C to 150°C for 1 min to 60 min.

[0013] Furthermore, the perovskite layer is an ABX3 perovskite light-absorbing layer, where A is CH3NH3 + or CH(NH2) 2+ one or both of them, B is Pb 2+ , and X is I - , Br - or Cl - ;

[0014] The electron transport layer is one or both of tin dioxide and titanium dioxide;

[0015] The hole transport layer is at least one of poly(3-hexylthiophene-2,5-diyl), 2,2',7,7'-tetrakis[N,N-bis(4-methoxyphenyl)amino]-9,9'-spirobifluorene, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], and nickel oxide.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] The present invention provides an application of an interfacial molecule with multifunctional active sites in a perovskite solar cell device. By spin coating the interfacial molecule on the perovskite layer, the film defects of the perovskite layer are effectively reduced, the average carrier lifetime of the perovskite film is increased, the interfacial recombination loss of the device is reduced, the roughness of the perovskite film is simultaneously reduced, the energy level arrangement of the device is improved, thereby improving the power conversion efficiency of the solar device, and the humidity stability of the device is also significantly improved. In addition, the lead leakage of the device is significantly suppressed, realizing the preparation of an environmentally friendly lead-based perovskite solar cell and promoting the large-scale and commercialization process of perovskite solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is the forward scan current-voltage curve graph of the perovskite solar cells in the comparative example and Example 1;

[0019] Figure 2 It is the perovskite light-absorbing layer defect graph of the perovskite solar cells in the comparative example and Example 1;

[0020] Figure 3 It is the carrier lifetime graph of the perovskite solar cells in the comparative example and Example 1;

[0021] Figure 4 It is the energy level arrangement graph of the perovskite solar cell in Example 1;

[0022] Figure 5 To conduct a moderate stability test on the perovskite solar cells in Comparative Example and Example 1 under the condition of relative humidity of 40%-50%;

[0023] Figure 6 To compare the lead leakage of perovskite solar cells in Comparative Example and Example 1 under different conditions;

[0024] Figure 7 For the forward current-voltage curve of the perovskite solar cell in Example 2;

[0025] Figure 8 For the forward current-voltage curve of the perovskite solar cell in Example 3;

[0026] Figure 9 For the forward current-voltage curve of the perovskite solar cell in Example 4;

[0027] Figure 10 For the forward current-voltage curve of the perovskite solar cell in Example 5;

[0028] Figure 11 For the forward current-voltage curve of the perovskite solar cell in Example 6. Specific Embodiments

[0029] The following specific examples illustrate the embodiments of the present invention. Those skilled in the art can easily understand the other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0030] Comparative Examples

[0031] A method for preparing a perovskite solar cell, comprising the following steps:

[0032] (1) The ITO conductive substrate is ultrasonically treated with detergent, deionized water, and absolute ethanol for 30 min in sequence, then dried with argon, and then treated with ultraviolet ozone for 30 min and cooled for standby;

[0033] (2) Add pure water (V SnO2 :V H2O= 1:3), mix well and then drop it onto the ITO conductive substrate treated in step (1). Then spin-coat it at a speed of 4000 rpm for 30 s, and then anneal it at 150 °C for 30 min to obtain the electron transport layer. Subsequently, perform ultraviolet ozone irradiation treatment on the electron transport layer for 20 min;

[0034] (3) Dissolve FAI (248 mg), PbBr2 (8.5 mg), RbI (6.6 mg), MACl (35.0 mg), PbI2 (682.7 mg), CsI (19.7 mg) and PbCl2 (12.7 mg) in a mixed solution of DMF and DMSO (V DMF :V DMSO = 4:1), after shaking for 5 min, drop the perovskite solution onto the electron transport layer prepared in step (2), spin-coat it at a speed of 4000 rpm for 30 s, and then anneal it at 130 °C for 28 min. Among them, 16 s before the end of the perovskite solution spin-coating, 80 μL of chlorobenzene is dropped within 2 s to obtain the perovskite light-absorbing layer;

[0035] (4) Dissolve 72.3 mg of 2,2',7,7'-tetrakis[N,N-bis(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Spiro-OMeTAD) in 1 mL of chlorobenzene, and add 29 μL of TBP and 18 μL of Li-TFSI (concentration: 520 mg / mL, solvent: anhydrous acetonitrile). After mixing well, drop it onto the perovskite light-absorbing layer prepared in step (3), and spin-coat it at a speed of 3000 rpm for 30 s to obtain the hole transport layer;

[0036] (5) Under high vacuum (10 -4 Pa), evaporate an Ag electrode with a thickness of 80 nm on the hole transport layer prepared in step (4) by thermal evaporation, and that's it.

[0037] Example 1

[0038] Method for preparing a perovskite solar cell:

[0039] The difference from the comparative example is that the following operations need to be carried out before step (4):

[0040] Dissolve the A4 molecule in isopropanol to prepare a modified layer solution with a concentration of 0.5 mg / mL, and then spin-coat it on the perovskite film, conditions: 5000 rpm, 30 s. No annealing is required after spin-coating to obtain the modified layer.

[0041]

[0042] Figure 1To compare the forward current-voltage curves of the perovskite solar cells in the comparative example and Example 1, and obtain the photovoltaic parameters of the two types of cells based on this graph. The results are shown in Table 1. It can be seen from Figure 1 and Table 1 that the efficiency of the perovskite solar cell in Example 1 has been significantly improved.

[0043] Table 1

[0044]

[0045] Figure 2 To compare the defect maps of the light-absorbing layers of the perovskite solar cells in the comparative example and Example 1, it can be seen that the defect density of the perovskite thin film in Example 1 has been significantly reduced.

[0046] Figure 3 To compare the carrier lifetime maps of the perovskite solar cells in the comparative example and Example 1, it can be seen that the carrier lifetime of the perovskite thin film in Example 1 has been significantly increased.

[0047] Figure 4 For the energy level arrangement diagram of the perovskite solar cell in Example 1, it can be seen that the energy level arrangement of the device in Example 1 is more conducive to the transport of carriers.

[0048] Figure 5 To compare the humidity stability tests of the perovskite solar cells in the comparative example and Example 1 under the condition of relative humidity of 40%-50%, the results show that after 500 hours, the device of Example 1 can still maintain more than 60% of the original efficiency, while the device of the comparative example has no efficiency left.

[0049] Figure 6 To compare the lead leakage situations of the perovskite solar cells in the comparative example and Example 1 under different conditions, it is found that there is only a trace amount of lead leakage in the device of Example 1, while the lead leakage content in the comparative example is 4 times that of Example 1. This shows that the molecular modification layer in Example 1 can effectively inhibit the lead leakage situation.

[0050] Example 2

[0051] The difference from Example 1 is that the modifier molecule A4 is replaced with A8, the concentration is 10 mg / mL, the rotation speed is 6000 rpm, and after spin coating, it needs to be annealed at 25 °C for 60 min.

[0052]

[0053]

[0054] Figure 7It is the forward sweep current-voltage curve graph of the perovskite solar cell in Example 2. It can be seen that the efficiency of this cell is 21.06%. Compared with the efficiency of the cell in the comparative example (20.83%), the device efficiency has been significantly improved.

[0055] Example 3

[0056] The difference from Example 1 is that the electron transport layer used in step (2) is titanium dioxide.

[0057] Figure 8 It is the forward sweep current-voltage curve graph of the perovskite solar cell in Example 3. It can be seen that the efficiency of this cell is 21.25%. Compared with the efficiency of the cell in the comparative example (20.83%), the device efficiency has been significantly improved.

[0058] Example 4

[0059] The difference from Example 1 is that the hole transport material used in step (4) is nickel oxide, the modifying molecule A4 is replaced by A12, the concentration is 0.1 mg / mL, and after the spin coating is completed, annealing is carried out at 100 °C for 5 min.

[0060]

[0061] Figure 9 It is the forward sweep current-voltage curve graph of the perovskite solar cell in Example 4. It can be seen that the efficiency of this cell is 21.56%. Compared with the efficiency of the cell in the comparative example (20.83%), the device efficiency has been significantly improved.

[0062] Example 5

[0063] The difference from Example 1 is that the modifying molecule A4 is replaced by A15, the concentration is 25 mg / mL, and after the spin coating is completed, annealing needs to be carried out at 60 °C for 30 min.

[0064]

[0065] Figure 10 It is the forward sweep current-voltage curve graph of the perovskite solar cell in Example 5. It can be seen that the efficiency of this cell is 21.50%. Compared with the efficiency of the cell in the comparative example (20.83%), the device efficiency has been significantly improved.

[0066] Example 6

[0067] The difference from Example 1 is that the modifying molecule A4 is replaced by A2, and the concentration is 11 mg / mL.

[0068]

[0069] Figure 11It is the forward current-voltage curve graph of the perovskite solar cell in Example 6. It can be seen that the efficiency of this cell is 21.22%. Compared with the efficiency of the cell in the comparative example (20.83%), the device efficiency has been significantly improved.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the purpose and scope of the present technical solution, and they should all be covered within the scope of the claims of the present invention.

Claims

1. Application of an interfacial molecule with multifunctional active sites, characterized in that, Applied as a modifier molecule in lead-based perovskite solar cell devices; the modifier molecule is spin-coated between the perovskite layer and the electron transport layer or the hole transport layer of the lead-based perovskite solar cell device; The interfacial molecule is a compound containing at least 3 groups of S, -C=O, -NH2, N, O and F, and the structural formula is as follows:

2. Use of an interfacial molecule having multifunctional active sites according to claim 1, characterized in that, The structure of the lead-based perovskite solar cell device is a normal structure or an inverted structure.

3. Use of an interfacial molecule having multifunctional active sites according to claim 1, characterized in that, The concentration of the modifier molecule is 0.1 mg / mL to 25 mg / mL, and after spin-coating, it is annealed at a temperature of 25°C to 150°C for 1 minute to 60 minutes.

4. Use of an interfacial molecule having a multifunctional active site according to claim 1, characterized in that, The perovskite layer is an ABX3 perovskite light-absorbing layer, where A is CH3NH3 + or CH(NH2) 2+ or one or both of them, B is Pb 2+ , X is I - , Br - or Cl - ; The electron transport layer is one or both of tin dioxide or titanium dioxide; The hole transport layer is at least one of poly(3-hexylthiophene-2,5-diyl), 2,2',7,7'-tetrakis[N,N-bis(4-methoxyphenyl)amino]-9,9'-spirobifluorene, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] or nickel oxide.

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