Preparation method of neutral color efficient semitransparent solar cell

Abstract

The invention relates to a preparation method of a neutral color high-efficiency semitransparent solar cell. The preparation method comprises the following steps: carrying out surface pretreatment on patterned ITO (Indium Tin Oxide) conductive glass; immersing the treated clean ITO conductive glass in a mixed solution of o-dichlorotoluene and hydrogen peroxide, carrying out ultraviolet treatment on the ITO conductive glass, cleaning residual reagents on the ITO surface by using absolute ethyl alcohol, and then carrying out ultraviolet ozone treatment to obtain a chlorinated ITO conductive glass anode; spin-coating a ternary mixed solution of PM6: BTP-eC9: PC71BM on the surface of the chlorinated ITO conductive glass anode in a glove box to obtain a photoactive layer; spin-coating a methanol solution of PNDIT-F3N on the optical active layer to obtain an electron transport layer; evaporating a silver electrode on the surface of the electron transport layer under a vacuum condition; and alternately evaporating a layer of lithium fluoride and molybdenum trioxide on the surface of the silver electrode to obtain a layer of simple DBR. The liquid crystal composition has excellent neutral color and good visible light transmittance.

Description

Technical Field

[0001] The invention belongs to the field of organic solar cells, and in particular relates to a method for preparing a neutral color high-efficiency semi-transparent solar cell. Background Art

[0002] Solution-processed organic solar cells (OSCs) have the advantages of light weight, multiple colors, translucency, and easy mass production, and have unique advantages in the field of building integrated photovoltaics (BIPV). In particular, organic semiconductor materials can absorb light of specific wavelengths by adjusting the energy level structure to obtain colorful semi-transparent organic solar cells (ST-OSCs), and they can also match each other to achieve good neutral colors. In order to realize the application of organic photovoltaics (OPV) in the field of BIPV (such as photovoltaic windows), ST-OSCs must not only meet excellent photoelectric conversion efficiency (PCE), but also have excellent neutral perceived color and good visible light transmittance to avoid visual fatigue caused by overly bright colors.

[0003] The color neutrality of ST-OSCs can be expressed by a color rendering index (CRI) of 0-100, where a higher CRI value means a better reflection of the color of the scene itself, corresponding to a better neutral color. In recent years, the efficiency of OSCs has developed rapidly, and the current highest PCE has exceeded 20%. However, these high-efficiency OSCs are based on opaque devices, and their optical performance (especially CRI) is not ideal. Therefore, the trade-off between photovoltaic performance and optical performance deserves in-depth study in ST-OSCs. In particular, it is necessary to further explore effective methods that can solve this trade-off problem in order to simultaneously improve the photovoltaic performance and neutral color perception of ST-OSCs. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a method for preparing a neutral color high-efficiency semi-transparent solar cell, by introducing a wide bandgap acceptor as a third component to compensate for the unbalanced absorption of the active layer in the visible light range, level the transmission spectrum, improve the color rendering index of ST-OSCs, and optimize the morphology of the active layer to achieve a balance between PCE and CRI, so that ST-OSCs have excellent neutral color and good visible light transmittance while maintaining high efficiency.

[0005] In order to solve the above technical problems, the present invention provides a method for preparing a neutral color high-efficiency semi-transparent solar cell, comprising the following steps:

[0006] (1) performing surface pretreatment on the patterned ITO conductive glass;

[0007] (2) immersing the clean ITO conductive glass treated in step (1) in a mixed solution of o-dichlorotoluene and hydrogen peroxide, treating the ITO conductive glass with ultraviolet light, and after the above treatment, cleaning the reagent remaining on the surface of the ITO with anhydrous ethanol, and performing ultraviolet ozone treatment again to obtain a chlorinated ITO conductive glass anode;

[0008] (3) PM6:BTP-eC9:PC 71 The ternary mixed solution of BM was spin-coated on the surface of chlorinated ITO conductive glass anode in a glove box to obtain a photoactive layer;

[0009] (4) spin coating a methanol solution of PNDIT-F3N on the photoactive layer obtained in step (3) to obtain an electron transport layer;

[0010] (5) evaporating a silver electrode on the surface of the electron transport layer obtained in step (4) under vacuum conditions;

[0011] (6) A layer of lithium fluoride and molybdenum trioxide are alternately evaporated on the surface of the silver electrode obtained in step (5) to obtain a simple DBR layer.

[0012] Preferably, the surface treatment method of ITO conductive glass in step (1) is: placing the patterned ITO conductive glass in deionized water, acetone, and isopropanol for ultrasonic cleaning in sequence, each ultrasonic cleaning lasting 15 minutes, then drying with pure nitrogen and placing it in a UV ozone cleaning device for 15 minutes.

[0013] Preferably, in the ITO conductive glass immersion step in step (2), the concentration of hydrogen peroxide used is 30%, the volume ratio of o-dichlorotoluene to hydrogen peroxide in the mixed solution is 15:2, the UV treatment time of the ITO conductive glass is 5 minutes, and the UV ozone treatment time of the ITO conductive glass is 15 minutes.

[0014] Preferably, the solvent in the ternary mixed solution in step (3) is toluene, and the dissolution condition is stirring at 60°C for 4 hours. 71 The mass ratio of BM is 1:0.8:0.4, the concentration of the ternary mixed solution is 17 mg / mL and DIO with a volume fraction of 0.5% is used as an additive. The spin coating conditions of the spin coating process are spin coating at a rotation speed of 2500 rpm for 30 seconds, and the thickness of the active layer is 110 nm. After the spin coating is completed, the sample is transferred to a heating table and annealed at 100° C. for 10 minutes.

[0015] Preferably, the concentration of the PNDIT-F3N solution in step (4) is 0.5 mg / mL, and acetic acid with a volume fraction of 0.5% is used for dissolution, and the spin coating condition is spin coating at a rotation speed of 4000 rpm for 30 seconds.

[0016] Preferably, the vacuum condition in step (5) is a vacuum degree greater than 5×10 -6 mbar, and the obtained silver electrode thickness is 15nm.

[0017] Preferably, in the DBR structure in step (6), the thicknesses of lithium fluoride and molybdenum trioxide are 62.4 nm and 37.3 nm respectively.

[0018] Advantages of the present invention: The method for preparing a neutral color high-efficiency semi-transparent solar cell described in the present invention introduces a wide bandgap acceptor as the third component to compensate for the unbalanced absorption of the active layer in the visible light range, level the transmission spectrum, improve the color rendering index of ST-OSCs, and optimize the morphology of the active layer to achieve a balance between PCE and CRI, so that ST-OSCs have excellent neutral color and good visible light transmittance while maintaining high efficiency. The solar cell prepared by this method can be adjusted by adjusting the donor-acceptor ratio, and cooperated with a simple distributed Bragg reflector to effectively level the transmission spectrum and obtain excellent neutral color; at the same time, this strategy can effectively improve the efficiency of the device and achieve a trade-off between the optical performance and photovoltaic performance of the semi-transparent organic photovoltaic device. In addition, the solvent selected by the present invention is an environmentally friendly solvent, which can reduce environmental pollution problems in the production process and is in line with the concept of green development. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is the structural formula of the ternary active layer material in this method.

[0020] Figure 2 Schematic diagram of the structure of the solar cell prepared by this method.

[0021] Figure 3 Schematic diagram of the energy band structure of the active layer material in the solar cell prepared by this method.

[0022] Figure 4 Absorption spectra of the active layer obtained with different blending ratios;

[0023] Figure 5 Current density-voltage (JV) curves of ST-OSCs prepared with different blending ratios;

[0024] Figure 6 Transmittance spectra of ST-OSCs prepared with different blending ratios with and without DBR;

[0025] Figure 7 Color coordinates of ST-OSCs prepared with different blending ratios with and without DBR on the CIE 1931 chromaticity diagram;

[0026] Figure 8 The real scene photos of ST-OSCs prepared with different blending ratios with and without DBR shielding;

[0027] Fig. 9 Current density-voltage curves of ST-OSCs (with DBR) prepared with different blending ratios; DETAILED DESCRIPTION

[0028] A method for preparing a neutral color high-efficiency semi-transparent solar cell comprises the following steps:

[0029] (1) performing surface pretreatment on the patterned ITO conductive glass;

[0030] (2) immersing the clean ITO conductive glass treated in step (1) in a mixed solution of o-dichlorotoluene and hydrogen peroxide, treating the ITO conductive glass with ultraviolet light, and after the above treatment, cleaning the reagent remaining on the surface of the ITO with anhydrous ethanol, and performing ultraviolet ozone treatment again to obtain a chlorinated ITO conductive glass anode;

[0031] (3) PM6:BTP-eC9:PC 71 The ternary mixed solution of BM was spin-coated on the surface of chlorinated ITO conductive glass anode in a glove box to obtain a photoactive layer;

[0032] (4) spin coating a methanol solution of PNDIT-F3N on the photoactive layer obtained in step (3) to obtain an electron transport layer;

[0033] (5) evaporating a silver electrode on the surface of the electron transport layer obtained in step (4) under vacuum conditions;

[0034] (6) A layer of lithium fluoride and molybdenum trioxide are alternately evaporated on the surface of the silver electrode obtained in step (5) to obtain a simple DBR layer.

[0035] The surface treatment method of ITO conductive glass in step (1) is as follows: placing the patterned ITO conductive glass in deionized water, acetone, and isopropanol for ultrasonic cleaning in sequence, each ultrasonic cleaning lasting 15 minutes, then drying with pure nitrogen and placing in a UV ozone cleaning device for 15 minutes.

[0036] In the ITO conductive glass immersion step in step (2), the hydrogen peroxide concentration used is 30%, the volume ratio of o-dichlorotoluene to hydrogen peroxide in the mixed solution is 15:2, the UV treatment time of the ITO conductive glass is 5 minutes, and the UV ozone treatment time of the ITO conductive glass is 15 minutes.

[0037] In the step (3), the solvent in the ternary mixed solution is toluene, and the dissolution condition is stirring at 60° C. for 4 hours. PM6, BTP-eC9 and PC in the ternary mixed solution are 71 The mass ratio of BM is 1:0.8:0.4, the concentration of the ternary mixed solution is 17 mg / mL and DIO with a volume fraction of 0.5% is used as an additive. The spin coating conditions of the spin coating process are spin coating at a rotation speed of 2500 rpm for 30 seconds, and the thickness of the active layer is 110 nm. After the spin coating is completed, the sample is transferred to a heating table and annealed at 100° C. for 10 minutes.

[0038] The concentration of the PNDIT-F3N solution in step (4) is 0.5 mg / mL, and acetic acid with a volume fraction of 0.5% is used for dissolution. The spin coating condition is to spin coat at a rotation speed of 4000 rpm for 30 seconds.

[0039] The vacuum condition of step (5) is a vacuum degree greater than 5×10 -6 mbar, and the obtained silver electrode thickness is 15nm.

[0040] In the DBR structure in step (6), the thicknesses of lithium fluoride and molybdenum trioxide are 62.4 nm and 37.3 nm respectively.

[0041] See also Figure 1 , Figure 2 , the method for preparing a neutral color high-efficiency semi-transparent solar cell described in this embodiment introduces a wide bandgap acceptor as the third component to compensate for the unbalanced absorption of the active layer in the visible light range, level the transmission spectrum, improve the color rendering index of ST-OSCs, and optimize the morphology of the active layer to achieve a balance between PCE and CRI, so that ST-OSCs have excellent neutral color and good visible light transmittance while maintaining high efficiency. The solar cell prepared by this method can be adjusted by adjusting the donor-acceptor ratio, and cooperated with a simple distributed Bragg reflector to effectively level the transmission spectrum and obtain excellent neutral color; at the same time, this strategy can effectively improve the efficiency of the device and achieve a trade-off between the optical performance and photovoltaic performance of the semi-transparent organic photovoltaic device. In addition, the solvent selected in this embodiment is an environmentally friendly solvent, which can reduce environmental pollution problems in the production process and is in line with the concept of green development.

[0042] Figure 3Schematic diagram of the energy band structure of the active layer materials for preparing neutral color high-efficiency semi-transparent photovoltaic devices. The different energy gap sizes of the three materials correspond to absorption spectra of different bands, which can achieve complementary absorption of sunlight in the mixed film, which is beneficial to the improvement of OSCs efficiency. It also means that the color of ST-OSCs can be adjusted by adjusting the proportion of each component. In addition, the energy level structure of the three that matches each other is conducive to the transfer of charges between donors and acceptors, and can ensure its high photoelectric conversion efficiency while realizing neutral color ST-OSCs.

[0043] Comparative experiment:

[0044] Table 1 shows the photovoltaic and optical parameters of ST-OSCs (with DBR) prepared with different blending ratios.

[0045]

[0046] Figure 4 The absorption spectra of the active layer obtained with different blending ratios are shown in Figure 2. 71 Compared with the binary films of PM6-Ir1:BTP-eC9 (1:1.2) and PM6-Ir1:BTP-eC9 (1:1.2), the ternary films with optimized mass ratio (PM6-Ir1:BTP-eC9:PC 71 BM=1:0.8:0.4) shows a flatter absorption spectrum in the entire visible light region. 71 With the increase of BM content, the intensity of the absorption spectrum in the short wavelength region increases to varying degrees. At the same time, the intensity in the long wavelength region decreases accordingly. Figure 8 From the bright color of cherry blossoms in the real scene photos, it can be seen that the flat absorption spectrum of the ternary blend is beneficial to its neutral color rendering performance.

[0047] Figure 5 Current density-voltage (JV) curves of ST-OSCs prepared with different blending ratios. 71 With the increase of BM content, the photoelectric conversion efficiency of the ternary device first increases and then decreases. Figure 4 ,PM6-Ir1:BTP-eC9:PC 71 The BM (1:0.8:0.4) ternary device has high efficiency and a flat absorption spectrum, making it the best choice.

[0048] Figure 6 The transmittance spectra of ST-OSCs prepared with different blending ratios with and without DBR. DBR can effectively adjust the transmittance performance of ST-OSCs, making it show a flatter transmittance spectrum in the full band. Figure 8It can be clearly seen from the comparison of real scenes and objects that the use of DBR can greatly improve the color rendering ability of ST-OSCs.

[0049] Figure 7 Color coordinates of ST-OSCs prepared with different blending ratios with and without DBR on the CIE 1931 chromaticity diagram. 71 BM content increased to PM6-Ir1:BTP-eC9:PC 71 BM=1:0.8:0.4, the CRI value of ST-OSCs gradually increases, and the use of DBR makes its color rendering index closer to white, indicating its excellent neutral color rendering ability.

[0050] Figure 8 The following are photos of real scenes of ST-OSCs prepared with different blending ratios with and without DBR shielding. Figure 7 Correspondingly, PM6-Ir1:BTP-eC9:PC combined with DBR 71 The BM (1:0.8:0.4) ternary device exhibits the best neutral color rendering ability.

[0051] Fig. 9 The JV curves of ST-OSCs (with DBR) prepared with different blending ratios are shown in Table 1. The corresponding photovoltaic and optical parameters are summarized in Table 1, where AVT represents the average transmittance of ST-OSCs. The JV curves of the three ST-OSCs are similar, PM6-Ir1:BTP-eC9:PC 71 The BM (1:0.8:0.4) ternary device has a PCE value of 14.09%, which is slightly lower than that of PM6-Ir1:BTP-eC9:PC 71 BM (1:1:0.2) ternary device, however, has an AVT value of 20.44% and a CRI value of 96.5, which are significantly higher than the other two devices. 71 The BM (1:0.8:0.4) ternary device shows higher advantages in the field of neutral color semi-transparent solar cells.

Claims

1. A method for preparing a neutral color high-efficiency semi-transparent solar cell, characterized in that: The following steps are involved: (1) performing surface pretreatment on the patterned ITO conductive glass; (2) immersing the clean ITO conductive glass treated in step (1) in a mixed solution of o-dichlorotoluene and hydrogen peroxide, treating the ITO conductive glass with ultraviolet light, and after the above treatment, cleaning the reagent remaining on the surface of the ITO with anhydrous ethanol, and performing ultraviolet ozone treatment again to obtain a chlorinated ITO conductive glass anode; (3) PM6:BTP-eC9:PC 71 The ternary mixed solution of BM was spin-coated on the surface of chlorinated ITO conductive glass anode in a glove box to obtain a photoactive layer; (4) spin coating a methanol solution of PNDIT-F3N on the photoactive layer obtained in step (3) to obtain an electron transport layer; (5) evaporating a silver electrode on the surface of the electron transport layer obtained in step (4) under vacuum conditions; (6) A layer of lithium fluoride and molybdenum trioxide are alternately evaporated on the surface of the silver electrode obtained in step (5) to obtain a simple DBR layer.

2. The method for preparing a neutral color high-efficiency semi-transparent solar cell according to claim 1, characterized in that: The surface treatment method of ITO conductive glass in step (1) is as follows: placing the patterned ITO conductive glass in deionized water, acetone, and isopropanol for ultrasonic cleaning in sequence, each ultrasonic cleaning lasting 15 minutes, then drying with pure nitrogen and placing in a UV ozone cleaning device for 15 minutes.

3. The method for preparing a neutral color high-efficiency semi-transparent solar cell according to claim 1, characterized in that: In the ITO conductive glass immersion step in step (2), the hydrogen peroxide concentration used is 30%, the volume ratio of o-dichlorotoluene to hydrogen peroxide in the mixed solution is 15:2, the UV treatment time of the ITO conductive glass is 5 minutes, and the UV ozone treatment time of the ITO conductive glass is 15 minutes.

4. The method for preparing a neutral color high-efficiency semi-transparent solar cell according to claim 1, characterized in that: In the step (3), the solvent in the ternary mixed solution is toluene, and the dissolution condition is stirring at 60° C. for 4 hours. PM6, BTP-eC9 and PC in the ternary mixed solution are 71 The mass ratio of BM is 1:0.8:0.4, the concentration of the ternary mixed solution is 17 mg / mL and DIO with a volume fraction of 0.5% is used as an additive. The spin coating conditions of the spin coating process are spin coating at a rotation speed of 2500 rpm for 30 seconds, and the thickness of the active layer is 110 nm. After the spin coating is completed, the sample is transferred to a heating table and annealed at 100° C. for 10 minutes.

5. The method for preparing a neutral color high-efficiency semi-transparent solar cell according to claim 1, characterized in that: The concentration of the PNDIT-F3N solution in step (4) is 0.5 mg / mL, and acetic acid with a volume fraction of 0.5% is used for dissolution. The spin coating condition is to spin coat at a rotation speed of 4000 rpm for 30 seconds.

6. The method for preparing a neutral color high-efficiency semi-transparent solar cell according to claim 1, characterized in that: The vacuum condition of step (5) is a vacuum degree greater than 5×10 -6 mbar, and the obtained silver electrode thickness is 15nm.

7. The method for preparing a neutral color high-efficiency semi-transparent solar cell according to claim 1, characterized in that: In the DBR structure in step (6), the thicknesses of lithium fluoride and molybdenum trioxide are 62.4 nm and 37.3 nm respectively.

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