A modified transmission layer slurry, its preparation method and application

Abstract

The application provides a modified transmission layer slurry as well as a preparation method and application thereof. The modified transmission layer slurry comprises A and B; the A comprises PEDOT:PSS or PFN-Br; and the B comprises an amino acid. The PEDOT:PSS or PFN-Br is mixed with the amino acid to obtain the modified transmission layer slurry. In the application, the modified transmission layer slurry is modified by using the amino acid on the PEDOT:PSS or PFN-Br, so that the open-circuit voltage, short-circuit current and conversion efficiency of an organic solar cell comprising the modified transmission layer are improved, and the fill factor is higher.

Description

Technical Field

[0001] This invention belongs to the field of solar cell technology, specifically relating to a modified transport layer paste, its preparation method, and its application. Background Technology

[0002] Due to the inexhaustible nature of solar energy, the photovoltaic industry is a green energy industry friendly to humankind. Currently, silicon-based solar cells are the most maturely used in industry and daily life. However, due to their complex manufacturing process and high cost, researchers worldwide have begun to research next-generation solar cells. Among third-generation solar cells, organic solar cells have been widely studied due to the excellent photoelectric properties of organic semiconductors. However, although organic semiconductors have advantages such as high absorbance, high carrier mobility, easily tunable band gap, and low raw material cost, the potential barrier between organic semiconductors and metal electrodes hinders carrier transport. Therefore, reducing this interfacial barrier is currently the most pressing problem to be solved.

[0003] In existing technologies, research is often conducted on the materials of the active layer to improve the performance of solar cells. For example, CN109326716A discloses a non-fullerene organic solar cell, comprising an ITO glass, an electron transport layer, an active layer, a hole transport layer, and an anode arranged sequentially. The active layer material includes a donor material, an acceptor material, and an additive. The donor material is PTB7-th, the acceptor material is ITIC, and the additive is sodium stearate. The electron transport layer material includes zinc oxide, and the hole transport layer material includes molybdenum trioxide. Adding sodium stearate to the active layer material promotes improvements in the current and efficiency of the non-fullerene organic solar cell. However, the current and conversion efficiency of this solar cell need further improvement.

[0004] CN108550699A discloses a ternary organic solar cell structure and its fabrication method based on small-molecule non-fullerene acceptors. From bottom to top, the structure comprises a transparent conductive substrate, an electron transport layer, a ternary organic active layer, a hole transport layer, and a metal electrode. The ternary organic active layer includes a polymer, a fullerene derivative, and a small-molecule non-fullerene acceptor. The study investigated the effects of adding small-molecule non-fullerene acceptors with different crystallinities as ternary dopants on device performance. Furthermore, the study characterized the influence of crystallinity differences on morphology optimization when small-molecule non-fullerene acceptors are used as ternary dopants, providing guidance for the design of non-fullerene acceptors in later stages. However, the light conversion efficiency, short-circuit current, and open-circuit voltage of the obtained solar cells need further improvement.

[0005] In organic solar cells, the device structure mainly consists of four parts: the substrate, the light-absorbing active layer, the charge transport layer, and the electrodes. The main function of the active layer is to absorb light and generate charge carriers. Then, the other two charge transport layers (located on either side of the active layer, namely the electron transport layer and the hole transport layer) are responsible for collecting charges, distributing them to their respective electrodes, and generating energy. Typically, the electron transport layer and the hole transport layer between the electrodes and the active layer play a crucial role and can affect the performance of the solar cell. Therefore, researching higher-performance transport layers and reducing interfacial barriers is of great importance for improving the performance of solar cells.

[0006] Therefore, developing a charge transport layer that can improve the open-circuit voltage, short-circuit current, and conversion efficiency of non-fullerene organic solar cells, while having a low fill factor, is an urgent problem to be solved in this field. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a modified transport layer slurry, its preparation method, and its applications. The modified transport layer slurry, through modification of PEDOT:PSS or PFN-Br with amino acids, improves the open-circuit voltage, short-circuit current, fill factor, and conversion efficiency of organic solar cells including the modified transport layer.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a modified transport layer slurry, the modified transport layer slurry comprising A and B; wherein A comprises PEDOT:PSS or PFN-Br; and wherein B comprises amino acids.

[0010] In this invention, the chemical structure of amino acids consists of two different functional groups: a carboxyl group on one end and an amino group on the other. The carboxyl group has electron-accepting ability, while the amino group has electron-donating ability. Furthermore, amino acids can form chemical bonds, exhibiting high miscibility and binding capacity, which facilitates covalent modification with other compounds. They are also safe and readily available. Modifying PEDOT:PSS or PFN-Br with amino acids can overcome the disadvantages of interfacial barriers, helping the transport layer to effectively extract charges, thereby improving device efficiency.

[0011] Preferably, based on a volume of 1 mL of PEDOT:PSS, the mass of the amino acid is 0.5–2 mg, for example, 0.6 mg, 0.7 mg, 0.8 mg, 0.9 mg, 1 mg, 1.1 mg, 1.2 mg, 1.3 mg, 1.4 mg, 1.5 mg, 1.6 mg, 1.7 mg, 1.8 mg, 1.9 mg, etc.

[0012] In this invention, with the volume of PEDOT:PSS being 1 mL, the mass of the amino acid is within a specific range, resulting in better device efficiency.

[0013] Preferably, the mass ratio of PFN-Br to amino acids is (0.25-5):1, for example, it can be 0.3:1, 0.5:1, 0.8:1, 1:1, 1.5:1, 1.8:1, 2:1, 2.2:1, 2.4:1, 2.6:1, 2.8:1, 3:1, 3.2:1, 3.4:1, 3.6:1, 3.8:1, 4:1, 4.2:1, 4.4:1, 4.6:1, 4.8:1, etc.

[0014] In this invention, the device efficiency is better when the mass ratio of PFN-Br to amino acids is within a specific range.

[0015] Preferably, the amino acid contains 2 to 20 carbon atoms, for example, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, etc.

[0016] Preferably, the amino acid includes at least one selected from β-alanine, glycine, 2-aminobutyric acid, phenylalanine, glutamic acid, and isoleucine.

[0017] In a second aspect, the present invention provides a method for preparing the modified transport layer slurry according to the first aspect, the preparation method comprising the following steps:

[0018] The modified transport layer slurry is obtained by mixing PEDOT:PSS or PFN-Br with amino acids.

[0019] Preferably, the mixing time is 2 to 14 hours, for example, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, 13 hours, etc.

[0020] In this invention, the mixing time of PEDOT:PSS with amino acids is 2-5 h; the mixing time of PFN-Br with amino acids is 10-14 h.

[0021] Preferably, the mixing of PFN-Br with the amino acid is carried out in a solvent.

[0022] Preferably, the solvent includes methanol.

[0023] Preferably, based on a total mass of PFN-Br and amino acids of 1 mg, the volume of methanol is 1 to 3 mL, for example, 1.5 mL, 2 mL, 2.5 mL, etc.

[0024] Thirdly, the present invention provides an organic solar cell, the organic solar cell comprising a first electrode, a hole transport layer, an active layer, an electron transport layer, and a second electrode stacked sequentially; the pastes of the hole transport layer and the electron transport layer each independently comprise the modified transport layer paste as described in the first aspect; the paste of the hole transport layer comprises PEDOT:PSS and amino acids; the paste of the electron transport layer comprises PFN-Br and amino acids.

[0025] Preferably, the first electrode comprises indium tin oxide conductive glass.

[0026] Preferably, the active layer comprises a bulk heterojunction active layer of PM6:Y6.

[0027] Preferably, the mass ratio of PM6 to Y6 in the slurry of the PM6:Y6 bulk heterojunction active layer is 1:(1-2), for example, it can be 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9, etc.

[0028] Preferably, the slurry of the PM6:Y6 bulk heterojunction active layer further includes additives.

[0029] Preferably, the additive includes 1-chloronaphthalene.

[0030] Preferably, the solvent for the slurry of the PM6:Y6 bulk heterojunction active layer includes chloroform.

[0031] Preferably, the second electrode comprises an aluminum electrode.

[0032] Preferably, the thickness of the second electrode is 80-120 nm, for example, it can be 90 nm, 95 nm, 100 nm, 105 nm, 110 nm, 115 nm, etc.

[0033] Preferably, the organic solar cell comprises a non-fullerene organic solar cell.

[0034] Fourthly, the present invention provides a method for preparing an organic solar cell according to the third aspect, the method comprising the following steps:

[0035] The first electrode, hole transport layer, active layer, electron transport layer, and second electrode are stacked sequentially to obtain the solar cell.

[0036] Preferably, the method for preparing the hole transport layer includes the following steps:

[0037] PEDOT:PSS is mixed with amino acids to obtain a slurry for the hole transport layer; the slurry is coated onto the surface of a first substrate and dried to obtain the hole transport layer.

[0038] Preferably, the coating method includes spin coating.

[0039] Preferably, the coating rotation speed is 3000-5000 rpm, for example, 3200 rpm, 3400 rpm, 3600 rpm, 3800 rpm, 4000 rpm, 4200 rpm, 4400 rpm, 4600 rpm, 4800 rpm, etc.

[0040] Preferably, the drying temperature is 140-160°C, for example, 145°C, 150°C, 155°C, etc.

[0041] In this invention, before coating, a pretreatment step of the first substrate is further included.

[0042] Preferably, the pretreatment includes washing with detergent, water, ethanol and isopropanol in sequence.

[0043] In this invention, all washing is performed under ultrasonic conditions, and the washing time is 10 to 20 minutes, for example, 12 minutes, 15 minutes, 18 minutes, etc.

[0044] Preferably, after the washing is completed, the process further includes treatment with an ultraviolet ozone generator.

[0045] In this invention, the treatment time using the ultraviolet ozone generator is 10 to 20 minutes, for example, 12 minutes, 15 minutes, 18 minutes, etc.

[0046] Preferably, the method for preparing the active layer includes: coating the active layer slurry onto the surface of the hole transport layer away from the first substrate, and annealing to obtain the active layer.

[0047] In this invention, the preparation method of the active layer slurry includes: mixing non-fullerene acceptor Y6 and polymer donor PM6 in a solvent, adding additive 1-chloronaphthalene 20-40 min before preparing the active layer, stirring, and obtaining the active layer slurry.

[0048] Preferably, the stirring temperature is 30-45°C, for example, 32°C, 35°C, 38°C, 40°C, 42°C, 44°C, etc.

[0049] Preferably, the stirring time is 1 to 3 hours. For example, it can be 1.5 hours, 2 hours, 2.5 hours, etc.

[0050] Preferably, the active layer is prepared under inert gas conditions.

[0051] Preferably, the inert gas includes, but is not limited to, nitrogen.

[0052] Preferably, the method for coating the active layer with a slurry includes spin coating.

[0053] Preferably, the rotation speed for coating the active layer with the slurry is 2000-4000 rpm, for example, 2500 rpm, 3000 rpm, 3500 rpm, etc.

[0054] Preferably, the annealing temperature is 90-120°C, for example, 95°C, 100°C, 105°C, 110°C, 115°C, etc.

[0055] Preferably, the annealing time is 8 to 12 minutes, for example, 9 minutes, 10 minutes, 11 minutes, etc.

[0056] Preferably, the method for preparing the electron transport layer includes: mixing the PFN-Br and amino acids in a solvent to obtain a slurry for the electron transport layer; and coating the slurry onto the surface of the active layer away from the hole transport layer to obtain the electron transport layer.

[0057] Preferably, the coating method includes spin coating.

[0058] Preferably, the coating rotation speed is 2000-4000 rpm, for example, 2500 rpm, 3000 rpm, 3500 rpm, etc.

[0059] Preferably, the method for obtaining the second electrode includes: depositing a metallic material on the surface of the electron transport layer away from the active layer to obtain the second electrode.

[0060] Preferably, the deposition pressure is (0.8~1.2)×10⁻⁶. 4 Pa, for example, can be 0.9 × 10 -4 Pa, 1×10 - 4 Pa, 1.1×10 -4 Pa, etc.

[0061] Preferably, the deposition temperature is 25–26°C.

[0062] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0063] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0064] The modified transport layer slurry provided by the present invention uses amino acids to modify PEDOT:PSS or PFN-Br, thereby improving the open-circuit voltage, short-circuit current, fill factor and conversion efficiency of organic solar cells including the modified transport layer. Attached Figure Description

[0065] Figure 1 Infrared spectra of the modified transport layer slurries provided in Examples 1-4;

[0066] Figure 2 Voltage-current curves of organic solar cells provided for Application Example 1 and Comparative Application Example 1;

[0067] Figure 3 This is a schematic diagram of the organic solar cell structure provided in Application Example 1 of the present invention;

[0068] Figure 4 This is the infrared spectrum of β-alanine. Detailed Implementation

[0069] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention.

[0070] The materials used in this invention are as follows:

[0071] PEDOT:PSS: Purchased from Heraeus, Germany (CLEVIOSTM PVP Al 4083)

[0072] PM6: Purchased from Solarmer Material Company

[0073] Y6: Purchased from Solarmer Material Company

[0074] PFN-Br: Purchased from Solarmer Material Company

[0075] β-Alanine: Purchased from Shanghai Jizhi Biochemical Technology Co., Ltd.

[0076] Glycine: Purchased from Shanghai Jizhi Biochemical Technology Co., Ltd.

[0077] 2-Aminobutyric acid: Purchased from Shanghai Jizhi Biochemical Technology Co., Ltd.

[0078] Chloroform and 1-chloronaphthalene: purchased from Sigma-Aldrich

[0079] Example 1

[0080] This embodiment provides a modified transport layer slurry comprising 10 mL PEDOT:PSS and 10 mg β-alanine.

[0081] The method for preparing the modified transport layer slurry includes: adding β-alanine to a PEDOT:PSS solution, mixing and stirring for 3 hours to obtain the modified transport layer slurry.

[0082] Example 2

[0083] This embodiment provides a modified transport layer slurry comprising 10 mM LPEDOT:PSS and 5 mg β-alanine. The preparation method of the modified transport layer slurry is the same as in Example 1.

[0084] Example 3

[0085] This embodiment provides a modified transport layer slurry comprising 10 mM LPEDOT:PSS and 15 mg β-alanine. The preparation method of the modified transport layer slurry is the same as in Example 1.

[0086] Example 4

[0087] This embodiment provides a modified transport layer slurry comprising 10 mM LPEDOT:PSS and 20 mg β-alanine. The preparation method of the modified transport layer slurry is the same as in Example 1.

[0088] The structures of the slurries obtained in Examples 1-4 were characterized using Fourier transform infrared spectroscopy, and the results are as follows: Figure 1 As shown; by Figure 1 As can be seen from the comparison with the infrared spectrum of PEDOT:PSS, it can be seen that PEDOT:PSS modified with different β-alanine concentrations has a higher spectral density at 1716 cm⁻¹. -1 A new peak appeared at [value missing], representing the extension of the carboxylic acid (C=O), indicating the introduction of a β-alanine functional group into PEDOT:PSS; the Fourier transform infrared spectrum of β-alanine is shown below. Figure 4 .

[0089] Example 5

[0090] This embodiment provides a modified transport layer slurry comprising 10 mM LPEDOT:PSS and 2.5 mg β-alanine. The preparation method of the modified transport layer slurry is the same as in Example 1.

[0091] Example 6

[0092] This embodiment provides a modified transport layer slurry comprising 10 mM LPEDOT:PSS and 25 mg β-alanine. The preparation method of the modified transport layer slurry is the same as in Example 1.

[0093] Example 7

[0094] This embodiment provides a modified transport layer slurry, which includes 40 mg PFN-Br and 10 mg β-alanine.

[0095] The method for preparing the modified transport layer slurry includes: dissolving PFN-Br and β-alanine in methanol to a solute concentration of 0.5 mg / mL, mixing and stirring for 12 h to obtain the modified transport layer slurry.

[0096] Example 8

[0097] This embodiment provides a modified transport layer slurry comprising 30 mg PFN-Br and 20 mg β-alanine. The preparation method of the modified transport layer slurry is the same as in Example 7.

[0098] Example 9

[0099] This embodiment provides a modified transport layer slurry comprising 20 mg PFN-Br and 30 mg β-alanine. The preparation method of the modified transport layer slurry is the same as in Example 7.

[0100] Example 10

[0101] This embodiment provides a modified transport layer slurry comprising 10 mg PFN-Br and 40 mg β-alanine. The preparation method of the modified transport layer slurry is the same as in Example 7.

[0102] Example 11

[0103] This embodiment provides a modified transport layer slurry comprising 6 mg PFN-Br and 44 mg β-alanine. The preparation method of the modified transport layer slurry is the same as in Example 7.

[0104] Example 12

[0105] This embodiment provides a modified transport layer slurry comprising 45 mg PFN-Br and 5 mg β-alanine. The preparation method of the modified transport layer slurry is the same as in Example 7.

[0106] Example 13

[0107] This embodiment provides a modified transport layer slurry, which differs from Example 1 only in that the β-alanine is replaced with glycine. The preparation method of the modified transport layer slurry is the same as that of Example 1.

[0108] Example 14

[0109] This embodiment provides a modified transport layer slurry, which differs from Example 7 only in that the β-alanine is replaced with 2-aminobutyric acid. The preparation method of the modified transport layer slurry is the same as that of Example 7.

[0110] Application Example 1

[0111] An organic solar cell, the structural schematic diagram of which is shown below. Figure 3 As shown, it includes sequentially stacked ITO conductive glass, hole transport layer (material is the modified transport layer slurry provided in Example 1), PM6:Y6 bulk heterojunction active layer, electron transport layer (material is the modified transport layer slurry provided in Example 7), and aluminum electrode (100nm).

[0112] The method for preparing the organic solar cell includes the following steps:

[0113] (1) After cleaning the ITO conductive glass with a cleaning agent, the ITO conductive glass was rinsed with distilled water, acetone and isopropanol in sequence for 15 minutes under ultrasonic conditions; then, it was treated with an ultraviolet ozone generator for 15 minutes; the modified transport layer slurry provided in Example 1 was spin-coated onto the surface of the treated ITO conductive glass at a speed of 4000 rpm to form a uniform film, and then baked at 150°C to obtain a hole transport layer.

[0114] (2) The stacked ITO conductive glass and hole transport layer obtained in step (1) are transferred to a glove box filled with nitrogen. PM6:Y6 bulk heterojunction active layer slurry is spin-coated on the surface of the hole transport layer at 3000 rpm. Then, it is annealed at 110°C for 10 minutes to obtain PM6:Y6 bulk heterojunction active layer.

[0115] (3) The modified transport layer slurry provided in Example 7 was spin-coated onto the surface of the PM6:Y6 bulk heterojunction active layer obtained in step (2) at a speed of 3000 rpm to obtain an electron transport layer; at a speed of 1×10 -4 Thermally deposited aluminum under vacuum pressure of Pa (through an active area of ​​0.04 cm²) 2The organic solar cell is obtained by using a shadow mask (deposition temperature of 25℃); the preparation method of the PM6:Y6 bulk heterojunction active layer slurry includes: dissolving non-fullerene acceptor Y6 and polymer donor PM6 in chloroform at a mass ratio of 1:1.2, with a solute concentration of 16 mg / mL, adding 0.5% 1-chloronaphthalene half an hour before preparing the photoactive layer, and stirring at 40℃ for 2 hours to obtain the PM6:Y6 bulk heterojunction active layer slurry.

[0116] The effective area is 0.04 square centimeters, the scanning voltage is -0.1V to 1.2V (forward scan), the step size is 0.1V, and the light source is 100mW / cm². 2 AM 1.5G, calibrated by a standard silicon cell, and then the current-voltage characteristics of the organic solar cell provided in Application Example 1 were calculated using a Keithley 2400 digital source meter, as shown in the results. Figure 2 As shown.

[0117] Application Example 2

[0118] An organic solar cell differs from Application Example 1 only in that the electron transport layer is made of the modified transport layer paste provided in Example 8, while the other materials, amounts, and preparation methods are the same as in Application Example 1.

[0119] Application Example 3

[0120] An organic solar cell differs from Application Example 1 only in that the electron transport layer is made of the modified transport layer paste provided in Example 9, while the other materials, amounts, and preparation methods are the same as in Application Example 1.

[0121] Application Example 4

[0122] An organic solar cell differs from Application Example 1 only in that the electron transport layer is made of the modified transport layer paste provided in Example 10, while the other materials, amounts, and preparation methods are the same as in Application Example 1.

[0123] Application Example 5

[0124] An organic solar cell differs from Application Example 1 only in that the electron transport layer is made of the modified transport layer paste provided in Example 11, while the other materials, amounts, and preparation methods are the same as in Application Example 1.

[0125] Application Example 6

[0126] An organic solar cell differs from Application Example 1 only in that the electron transport layer is made of the modified transport layer paste provided in Example 12, while the other materials, amounts, and preparation methods are the same as in Application Example 1.

[0127] Application Example 7

[0128] An organic solar cell differs from Application Example 1 only in that the hole transport layer is made of the modified transport layer paste provided in Example 2, while the other materials, amounts, and preparation methods are the same as in Application Example 1.

[0129] Application Example 8

[0130] An organic solar cell differs from Application Example 1 only in that the hole transport layer is made of the modified transport layer slurry provided in Example 3, while the other materials, amounts, and preparation methods are the same as in Application Example 1.

[0131] Application Example 9

[0132] An organic solar cell differs from Application Example 1 only in that the hole transport layer is made of the modified transport layer slurry provided in Example 4, while the other materials, amounts, and preparation methods are the same as in Application Example 1.

[0133] Application Example 10

[0134] An organic solar cell differs from Application Example 1 only in that the hole transport layer is made of the modified transport layer slurry provided in Example 5, while the other materials, amounts, and preparation methods are the same as in Application Example 1.

[0135] Application Example 11

[0136] An organic solar cell differs from Application Example 1 only in that the hole transport layer is made of the modified transport layer paste provided in Example 6, while the other materials, amounts, and preparation methods are the same as in Application Example 1.

[0137] Application Example 12

[0138] An organic solar cell differs from Application Example 1 only in that the electron transport layer is made of PFN-Br methanol solution and does not contain β-alanine; all other materials, amounts, and preparation methods are the same as in Application Example 1.

[0139] Application Example 13

[0140] An organic solar cell differs from Application Example 1 only in that the hole transport layer is made of PEDOT:PSS and does not contain β-alanine; all other materials, amounts, and preparation methods are the same as in Application Example 1.

[0141] Application Example 14

[0142] An organic solar cell differs from Application Example 1 only in that the hole transport layer is made of the modified transport layer paste provided in Example 13, while the other materials, amounts, and preparation methods are the same as in Application Example 1.

[0143] Application Example 15

[0144] An organic solar cell differs from Application Example 1 only in that the electron transport layer is made of the modified transport layer paste provided in Example 14, while the other materials, amounts, and preparation methods are the same as in Application Example 1.

[0145] Comparative Application Example 1

[0146] An organic solar cell differs from Application Example 1 only in that the hole transport layer is made of PEDOT:PSS and the electron transport layer is made of PFN-Br methanol solution. Neither the hole transport layer nor the electron transport layer is modified with β-alanine. All other materials, amounts, and preparation methods are the same as in Application Example 1.

[0147] The effective area is 0.04 square centimeters, the scanning voltage is -0.1V to 1.2V (forward scan), the step size is 0.1V, and the light source is 100mW / cm². 2 AM 1.5G, calibrated by a standard silicon cell, and then the current-voltage characteristics of the organic solar cell provided in Application Example 1 were calculated using a Keithley 2400 digital source meter, with the results as follows: Figure 2 As shown.

[0148] Comparative Application Example 2

[0149] An organic solar cell differs from Application Example 1 only in that the hole transport layer is made of β-alanine and the electron transport layer is made of β-alanine methanol solution; all other materials, amounts, and preparation methods are the same as in Application Example 1.

[0150] Performance testing

[0151] (1) Open circuit voltage: The voltage when the external circuit of the solar cell is disconnected or the current is zero, which is the maximum output voltage.

[0152] (2) Short-circuit current: The current density on the external circuit when the voltage applied to the solar cell is zero.

[0153] (3) Fill factor: The ratio of the maximum power provided by a solar cell under a certain load to the product of the open-circuit voltage and the short-circuit current.

[0154] (4) Photoelectric conversion efficiency: P max (Maximum output power) and P in The ratio of (incident monochromatic light power)

[0155] PCE = P max / P in =(V OC ×J SC ×FF) / Pin .

[0156] The specific test results are shown in Table 1:

[0157] Table 1

[0158]

[0159] As shown in the table above, the modified transport layer slurry provided by the present invention uses β-alanine to modify PEDOT:PSS or PFN-Br to obtain a hole transport layer or an electron transport layer; thereby improving the open-circuit voltage, short-circuit current, conversion efficiency, and fill factor of organic solar cells including the hole transport layer or electron transport layer.

[0160] As can be seen from the comparison between Application Example 1 and Application Examples 12 and 13, when the hole transport layer and electron transport layer of the organic solar cell are modified with a specific amount of β-alanine, the organic solar cell has better performance.

[0161] A comparison of Application Example 1 with Application Examples 10-11 shows that when the PEDOT:PSS and β-alanine are not in a specific mass-to-volume ratio, the overall performance of the organic solar cell is poor. A comparison of Application Example 1 with Application Examples 5-6 shows that when the PFN-Br and β-alanine are not in a specific mass ratio, the conversion efficiency of the organic solar cell is poor.

[0162] A comparison of Application Example 1 and Comparative Application Example 1 shows that without modification using β-alanine, the open-circuit voltage, short-circuit current, and conversion efficiency of the solar cell are all reduced. A comparison of Application Example 1 and Comparative Application Example 2 shows that when the hole transport layer and electron transport layer materials consist only of β-alanine, the solar cell performance is poor and the efficiency is low.

[0163] In summary, the modified transport layer provided by this invention, which modifies PEDOT:PSS or PFN-Br with β-alanine, can effectively improve the performance of traditional organic solar cells. Furthermore, the simultaneous use of β-alanine in both the hole transport layer and electron transport layer facilitates effective charge extraction on both the hole and electron transport sides of the device, further improving device efficiency.

[0164] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. An organic solar cell, characterized in that, The organic solar cell comprises a first electrode, a hole transport layer, an active layer, an electron transport layer, and a second electrode stacked sequentially. The slurries for the hole transport layer and the electron transport layer each independently include modified transport layer slurries; The slurry of the hole transport layer includes PEDOT:PSS and amino acids; The slurry of the electron transport layer includes PFN-Br and amino acids.

2. The organic solar cell according to claim 1, characterized in that, Based on a volume of 1 mL of PEDOT:PSS, the mass of the amino acid is 0.5~2 mg.

3. The organic solar cell according to claim 1, characterized in that, The mass ratio of PFN-Br to amino acids is (0.25~5):

1.

4. The organic solar cell according to claim 1, characterized in that, The amino acid contains 2 to 20 carbon atoms.

5. The organic solar cell according to claim 1, characterized in that, The amino acid includes at least one of β-alanine, glycine, 2-aminobutyric acid, phenylalanine, glutamic acid, and isoleucine.

6. The organic solar cell according to claim 1, characterized in that, The preparation method of the modified transport layer slurry includes the following steps: The modified transport layer slurry is obtained by mixing PEDOT:PSS or PFN-Br with amino acids.

7. The organic solar cell according to claim 6, characterized in that, The mixing time is 2 to 14 hours.

8. The organic solar cell according to claim 6, characterized in that, The mixing of PFN-Br with the amino acid is carried out in a solvent.

9. The organic solar cell according to claim 1, characterized in that, The first electrode comprises indium tin oxide conductive glass.

10. The organic solar cell according to claim 1, characterized in that, The active layer includes a bulk heterojunction active layer of PM6:Y6.

11. The organic solar cell according to claim 10, characterized in that, The mass ratio of PM6 to Y6 in the slurry of the PM6:Y6 bulk heterojunction active layer is 1:(1~2).

12. The organic solar cell according to claim 10, characterized in that, The slurry of the PM6:Y6 bulk heterojunction active layer also includes additives.

13. The organic solar cell according to claim 1, characterized in that, The second electrode includes an aluminum electrode.

14. The organic solar cell according to claim 1, characterized in that, The thickness of the second electrode is 80~120 nm.

15. The organic solar cell according to claim 1, characterized in that, The organic solar cells include non-fullerene organic solar cells.

16. A method for preparing an organic solar cell according to any one of claims 1 to 15, characterized in that, The preparation method includes the following steps: The first electrode, hole transport layer, active layer, electron transport layer, and second electrode are stacked sequentially to obtain the solar cell.

17. The preparation method according to claim 16, characterized in that, The method for preparing the hole transport layer includes the following steps: PEDOT:PSS is mixed with amino acids to obtain a slurry for the hole transport layer; the slurry is coated onto the surface of a first substrate and dried to obtain the hole transport layer.

18. The preparation method according to claim 17, characterized in that, The coating method includes spin coating.

19. The preparation method according to claim 17, characterized in that, The coating rotation speed is 3000~5000 rpm.

20. The preparation method according to claim 17, characterized in that, The drying temperature is 140~160℃.

21. The preparation method according to claim 16, characterized in that, The method for preparing the active layer includes: coating the active layer slurry onto the surface of the hole transport layer away from the first substrate, and annealing to obtain the active layer.

22. The preparation method according to claim 21, characterized in that, The active layer is prepared under inert gas conditions.

23. The preparation method according to claim 21, characterized in that, The method for coating the active layer with a slurry includes spin coating.

24. The preparation method according to claim 21, characterized in that, The slurry coating of the active layer is applied at a rotation speed of 2000~4000 rpm.

25. The preparation method according to claim 21, characterized in that, The annealing temperature is 90~120℃.

26. The preparation method according to claim 21, characterized in that, The annealing time is 8-12 minutes.

27. The preparation method according to claim 16, characterized in that, The method for preparing the electron transport layer includes: mixing the PFN-Br and amino acids in a solvent to obtain a slurry for the electron transport layer; and coating the slurry onto the surface of the active layer away from the hole transport layer to obtain the electron transport layer.

28. The preparation method according to claim 27, characterized in that, The coating method includes spin coating.

29. The preparation method according to claim 27, characterized in that, The coating rotation speed is 2000~4000 rpm.

30. The preparation method according to claim 16, characterized in that, The method for obtaining the second electrode includes: depositing a metallic material on the surface of the electron transport layer away from the active layer to obtain the second electrode.

31. The preparation method according to claim 30, characterized in that, The deposition pressure was (0.8~1.2)×10 - 4 Pa.

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