Low-temperature-resistant flexible photovoltaic glass and preparation method thereof

Abstract

The preparation method specifically comprises the following steps: depositing an ITO (Indium Tin Oxide) conductive layer through low-temperature PECVD (Poly Ether Chemical Vapor Deposition) (less than or equal to 80 DEG C), etching a honeycomb array with the porosity of 20-50% on the ITO layer, then uniformly coating the etched ITO surface with low-temperature-resistant high-ionic-conductivity polyacrylamide hydrogel modified by carbon dot CD (Coherent Diamond), and finally preparing the low-temperature-resistant flexible photovoltaic glass. The preparation method comprises the following steps: coating a mixed cationic perovskite precursor solution on a substrate, covering an organic silicon-acrylic acid composite moisture-proof layer with the thickness of 5 microns, spin-coating the mixed cationic perovskite precursor solution on the substrate by a solution spin-coating method to form a compact photoactive layer, evaporating a 100nm gold electrode on the surface, and finally preparing the flexible photovoltaic glass by a whole-process low-temperature process. The low-temperature comprehensive performance of the flexible photovoltaic glass is improved through four innovations of low-temperature PECVD (lower than or equal to 80 DEG C) deposition of the ITO conductive layer, etching of the honeycomb array with the porosity of 20%-50% on the ITO layer, carbon dot CD modified low-temperature-resistant high-ionic-conductivity polyacrylamide hydrogel and a whole-process low-temperature process, and the comprehensive performance index exceeds that of an existing flexible photovoltaic device by 5-10 times.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic glass preparation, and particularly relates to a low-temperature flexible photovoltaic glass and a preparation method thereof. Background Art

[0002] The comprehensive performance of flexible photovoltaic glass in a low-temperature environment is insufficient, which is the key technical bottleneck restricting its large-scale application in cold regions and high-altitude areas. Its technical bottleneck is mainly reflected in three aspects: First, the deposition of the traditional indium tin oxide conductive layer requires a high-temperature magnetron sputtering process above 200 °C, resulting in thermal shrinkage deformation (shrinkage rate ≥ 0.8%) of the polymer substrate (such as PET), and the interface thermal stress causes the expansion of the microcrack network; Second, the interfacial ion migration between the conductive layer and the perovskite layer is blocked in a low-temperature environment. When the temperature drops to -30 °C, the carrier transport impedance suddenly increases by 5-8 times, resulting in a decrease in the fill factor (FF) of more than 40%; Third, the conventional encapsulation system is prone to interlayer delamination under temperature difference shock. The difference in the thermal expansion coefficients of the moisture-proof layer and the photoactive layer results in an interfacial crack density of 150 cracks / mm at -20 °C 2 .

[0003] Existing improvement schemes such as doping silver nanowires can improve conductivity, but the resistivity increases sharply by 300% after 10 low-temperature bends 3 times; while the ion conductivity of the polyurethane-based encapsulant decays to 10 -5 S / cm at -40 °C, and it cannot maintain the perovskite lattice stability. These systematic defects make the power output attenuation rate of existing flexible photovoltaic devices as high as 1.2% / month in a low-temperature environment (-30 °C), seriously restricting their industrial applications in polar equipment, cold-region buildings and other fields. Summary of the Invention

[0004] By providing a low-temperature flexible photovoltaic glass and a preparation method thereof, the embodiments of the present application solve the problems of the low-temperature performance bottleneck of traditional flexible photovoltaic glass in the prior art, such as intolerance to low temperature, low ion conductivity at low temperature, and poor mechanical properties at low temperature, and achieve the technical effect of high comprehensive performance indicators (low-temperature resistance, high low-temperature bending life, and high low-temperature ion conductivity) of flexible photovoltaic glass at low temperature.

[0005] The embodiments of the present application provide a preparation method of a low-temperature flexible photovoltaic glass, characterized in that

[0006] it includes the following steps:

[0007] Step 1: Treatment of the flexible glass substrate and preparation of the conductive layer

[0008] Treat the flexible glass substrate with laser cleaning technology, deposit an ITO conductive layer on the substrate surface by low-temperature plasma-enhanced chemical vapor deposition, and use femtosecond laser to etch a honeycomb-shaped pore array with a diameter of 10-20 μm on the ITO layer surface to form a three-dimensional charge transport channel;

[0009] Step 2: Synthesis and modification of carbon dot-modified low-temperature-resistant hydrogel electrolyte

[0010] ① React citric acid and 3-aminobenzenesulfonic acid in N,N-dimethylformamide, add ethylenediamine and then heat under high pressure, and then obtain CD powder through ethanol precipitation, dialysis and freeze-drying;

[0011] ② Mix acrylamide, ammonium persulfate, N,N'-methylenebisacrylamide and a certain amount of CD powder and stir, pour it into a mold for cross-linking, then soak it in zinc trifluoromethanesulfonate solution, and finally dry it naturally to obtain PAM-CD hydrogel;

[0012] Step 3: Assembly of multi-layer structure of photovoltaic module

[0013] ① Use the spin-coating method to uniformly coat the PAM-CD hydrogel on the etched ITO surface to form a three-dimensional interlocking interface;

[0014] ② Cover the silicone-acrylic composite moisture-proof layer, and the mass ratio of silicone to acrylic acid is 3:1;

[0015] ③ Prepare a FA0.85MA0.15PbI2.85Br0.15 mixed-cation perovskite precursor solution, and the solvent is DMF = 4:1. Spin-coat the photovoltaic module in the second step of Step 3 in a nitrogen glove box for 30 s, and then perform solvent vapor annealing to form a dense photoactive layer;

[0016] ④ Evaporate a 100-nm gold electrode on the surface of the photovoltaic glass after the third step of Step 3, and the whole process temperature ≤ 80 °C to obtain flexible photovoltaic glass.

[0017] Preferably, the porosity of the honeycomb-shaped pore array in Step 1 is 20%-50%.

[0018] Preferably, in the second step of Step 2, the mass ratio of CD powder to acrylamide is 3:100.

[0019] Preferably, in the first step of Step 3, the thickness of the hydrogel is 300 μm, and the gel is filled into the microporous structure by vacuum infiltration.

[0020] Preferably, in the second step of Step 3, the thickness of the silicone-acrylic composite moisture-proof layer is 5 μm, and the water vapor transmission rate ≤ 0.5 g / m 2 / day.

[0021] An embodiment of the present invention also provides a low-temperature flexible photovoltaic glass, which is the flexible photovoltaic glass prepared by the above preparation method of the flexible photovoltaic glass.

[0022] One technical solution provided in the embodiments of the present application has at least the following technical effects:

[0023] 1. Through four major innovations of depositing an ITO conductive layer by low-temperature PECVD (≤80 °C), etching a honeycomb array with a porosity of 20%-50% in the ITO layer, a polyacrylamide hydrogel with high ion conductivity and low-temperature resistance modified by carbon dots CD, and a full-process low-temperature process, the present invention solves the bottleneck problems of low-temperature performance of flexible photovoltaic glass in the prior art, such as poor low-temperature resistance, low ion conductivity at low temperatures, and low mechanical strength, realizes the efficient and stable operation of flexible photovoltaic glass in extreme environments (-30 °C), and achieves excellent technical indicators such as an ion conductivity ≥2.0 mS / cm and a bending capacitance retention rate ≥85% at -30 °C. The comprehensive performance indicators (such as ion conductivity and low-temperature bending life) exceed those of existing flexible photovoltaic devices by 5-10 times.

[0024] 2. The temperature of the present invention embodiment is ≤80 °C from ITO deposition to gold electrode evaporation, combined with an organosilicon-acrylic moisture-proof layer (water vapor transmission rate ≤0.5 g / m 2 / day), realizing that the photoelectric efficiency attenuation of the flexible photovoltaic glass in extreme environments (-30 °C) is ≤12%, and the mechanical stability (-40 °C bending 1000 times, capacitance retention rate ≥85%).

[0025] 3. The present invention embodiment uses femtosecond laser to etch a honeycomb-shaped pore array with a diameter of 10-20 μm on the surface of the ITO layer, increasing the charge transfer area by 2 times and reducing the interface resistance to 2 Ω·cm 2 . Description of the Drawings

[0026] Figure 1 It is a comparison diagram of the low-temperature resistance test results of the modified PAM hydrogel electrolyte in Example 1 of the present application at -30 °C;

[0027] Figure 2 It is a SEM diagram of the modified PAM hydrogel electrolyte in Example 1 of the present application;

[0028] Figure 3 It is a diagram of the pore size and porosity results of the modified PAM hydrogel electrolyte in Example 1 of the present application;

[0029] Figure 4 It is a mechanical property diagram of the modified PAM hydrogel electrolyte in Example 1 of the present application;

[0030] Figure 5Ionic conductivity of the modified PAM hydrogel electrolyte in Example 1 of this application at different temperatures. Detailed implementation mode

[0031] By providing a low-temperature resistant flexible photovoltaic glass and a preparation method thereof, the embodiment of the present application solves the bottleneck problems of low-temperature performance of traditional flexible photovoltaic glass in the prior art, such as poor low-temperature resistance, low ionic conductivity at low temperatures, and poor mechanical properties at low temperatures, and realizes the technical effect of high comprehensive performance indexes (low-temperature resistance, high low-temperature bending life, and high low-temperature ionic conductivity) of flexible photovoltaic glass at low temperatures.

[0032] The technical solution in the embodiment of the present application to solve the above problems is generally as follows:

[0033] Deposit an ITO conductive layer by low-temperature PECVD (≤80°C), etch a honeycomb array with a porosity of 20%-50% on the ITO layer, and then uniformly coat the surface of the etched ITO with a polyacrylamide hydrogel modified by carbon dots CD with high low-temperature ionic conductivity, cover a 5-μm-thick silicone-acrylic composite moisture-proof layer, spin-coat the mixed cation perovskite precursor solution on the substrate by solution spin-coating to form a dense photoactive layer, and then evaporate a 100-nm gold electrode on the surface. The whole process is a low-temperature process, and finally a flexible photovoltaic glass is prepared. The efficient and stable operation of the flexible photovoltaic glass in an extreme environment (-30°C) is realized, and excellent technical indexes such as an ionic conductivity ≥2.0 mS / cm and a bending capacitance retention rate ≥85% at -30°C are achieved. The comprehensive performance indexes (such as ionic conductivity and low-temperature bending life) exceed those of existing flexible photovoltaic devices by 5-10 times.

[0034] To better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings of the specification and specific implementation modes.

[0035] Example 1

[0036] Step 1: Treatment of the flexible glass substrate and preparation of the conductive layer

[0037] (1) Use laser cleaning technology with a wavelength of 1064 nm and a power density of 20 W / cm 2 , remove the pollutants on the glass surface, and then etch the surface with argon plasma at a power of 50 W for 5 minutes to form a micron-level rough structure to enhance the adhesion.

[0038] (2) Deposit an ITO conductive layer on the substrate surface by low-temperature plasma-enhanced chemical vapor deposition, PECVD, with a temperature ≤80°C, a thickness controlled at 150-200 nm, and a sheet resistance ≤15 Ω / sq.

[0039] (3) Use femtosecond laser to etch a honeycomb pore array with a diameter of 10 - 20 μm on the surface of the ITO layer, with a wavelength of 1030 nm, a pulse width of 300 fs, a depth of 60% of the thickness of the conductive layer, and a porosity of 30% - 40% to form a three-dimensional charge transport channel.

[0040] Step 2: Synthesis and modification of low-temperature resistant hydrogel electrolyte

[0041] (1) Mix 1.728 g of citric acid and 0.7 g of 3-aminobenzenesulfonic acid in 20 mL of N,N-dimethylformamide and stir for 30 minutes to fully dissolve to obtain solution A. Then add 600 μL of ethylenediamine, stir well and pour it into the inner liner of an autoclave, and heat it in an oven at 160 °C for 5 hours. Subsequently, pour the reactant solution into ethanol, collect the brown precipitate by high-speed centrifugation, and then dissolve the precipitate in deionized water and dialyze it for 3 days. Among them, the cut-off molecular weight of the dialysis bag is 3500, and the dialysate is freeze-dried to obtain carbon dot CD powder.

[0042] (2) Add 2.5 g of acrylamide to 10 mL of water, stir and mix for 30 minutes, then add 15 mg of ammonium persulfate, 3 mg of N,N'-methylenebisacrylamide and 3% (relative to the mass of acrylamide) of CD powder, and stir and mix well for 2 h; pour the above well-stirred and mixed solution into a mold, crosslink it in an oven at 60 °C for 2 h, and after cooling, soak the hydrogel in a 2 M zinc trifluoromethanesulfonate solution for 12 h, take it out and dry it naturally to obtain modified polyacrylamide hydrogel PAM.

[0043] Step 3: Assembly of the multi-layer structure of the photovoltaic module

[0044] (1) Use the doctor blade method to evenly coat the hydrogel on the etched ITO surface with a thickness of 300 μm, and make the gel fill the microporous structure through vacuum infiltration, with a pressure of 0.1 MPa and a time of 30 min to form a three-dimensional interlocking interface.

[0045] (2) Cover a 5-μm-thick silicone-acrylic composite moisture-proof layer, with a mass ratio of silicone to acrylic of 3:1, cure it at 80 °C for 1 h, and the water vapor transmission rate ≤ 0.5 g / m 2 / day.

[0046] (3) Prepare a FA0.85MA0.15PbI2.85Br0.15 mixed-cation perovskite precursor solution, with a solvent of DMF = 4:1 and a concentration of 1.2 M. Spin-coat the photovoltaic module in step (2) of step 3 above at 2000 rpm for 30 s in a nitrogen glove box, and then perform solvent vapor annealing, in a DMSO atmosphere, at 50 °C for 10 min to form a dense photoactive layer.

[0047] (4) Evaporate a 100-nm gold electrode on the surface of the photovoltaic glass after step (3) of the above step three. The whole process temperature is ≤ 80 °C to avoid damaging the underlying gel electrolyte, and a flexible photovoltaic glass is obtained.

[0048] Perform performance tests on the flexible photovoltaic glass, and the results are as follows: Conduct a low-temperature bending test on the obtained flexible photovoltaic glass at -40 °C with a curvature radius of 5 mm for 1000 cycles, and the capacitance retention rate ≥ 80%, and the resistance change rate ≤ 5%; Conduct an ionic conductivity test on the flexible photovoltaic glass at -30 °C, and the ionic conductivity ≥ 1.8 mS / cm is measured by the four-probe method, and the efficiency decay ≤ 15%; Cyclic voltammetry test (scan rate 50 mV / s): Capacitance retention rate ≥ 90% (1000 cycles); Standard AM1.5G illumination (100 mW / cm 2 ) : The photoelectric conversion efficiency ≥ 18% (effective area 1 cm 2 ).

[0049] Example 2

[0050] The difference between this example and Example 1 lies in step one: The porosity of the honeycomb pore array in the flexible glass substrate treatment and the preparation of the conductive layer is 20% - 30%, and a flexible photovoltaic glass is obtained. Perform performance tests on it. For the low-temperature bending test at -40 °C with a curvature radius of 5 mm for 1000 cycles, the capacitance retention rate ≥ 75% and the resistance change rate ≤ 7% are obtained; Conduct an ionic conductivity test on the flexible photovoltaic glass at -30 °C, and the ionic conductivity ≥ 1.5 mS / cm is measured by the four-probe method, and the efficiency decay ≤ 18%; Cyclic voltammetry test (scan rate 50 mV / s): Capacitance retention rate ≥ 85% (1000 cycles); Standard AM1.5G illumination (100 mW / cm 2 ) : The photoelectric conversion efficiency ≥ 15% (effective area 1 cm 2 ).

[0051] Example 3

[0052] The difference between this example and Example 3 lies in step one: The porosity of the honeycomb pore array in the flexible glass substrate treatment and the preparation of the conductive layer is 40% - 50%, and a flexible photovoltaic glass is obtained. Perform performance tests on it. For the low-temperature bending test at -40 °C with a curvature radius of 5 mm for 1000 cycles, the capacitance retention rate ≥ 85% and the resistance change rate ≤ 5% are obtained; Conduct an ionic conductivity test on the flexible photovoltaic glass at -30 °C, and the ionic conductivity ≥ 2.0 mS / cm is measured by the four-probe method, and the efficiency decay ≤ 12%; Cyclic voltammetry test (scan rate 50 mV / s): Capacitance retention rate ≥ 95% (1000 cycles); Standard AM1.5G illumination (100 mW / cm 2 ) : The photoelectric conversion efficiency ≥ 20% (effective area 1 cm 2)。

[0053] The technical solutions in the embodiments of the present application at least have the following technical effects or advantages:

[0054] 1. Through four major innovations of depositing an ITO conductive layer by low-temperature PECVD (≤80°C), etching a honeycomb array with a porosity of 20%-50% in the ITO layer, a polyacrylamide hydrogel with high ion conductivity and low-temperature resistance modified by carbon dots CD, and a full-process low-temperature process, the present invention solves the bottleneck problems of low-temperature performance of flexible photovoltaic glass in the prior art, such as intolerance to low temperatures, low ion conductivity at low temperatures, and low mechanical strength, realizes the efficient and stable operation of flexible photovoltaic glass in extreme environments (-30°C), and achieves excellent technical indicators such as an ion conductivity ≥2.0 mS / cm and a bending capacitance retention rate ≥85% at -30°C. The comprehensive performance indicators (such as ion conductivity and low-temperature bending life) exceed those of existing flexible photovoltaic devices by 5-10 times.

[0055] 2. The temperature throughout the process from ITO deposition to gold electrode evaporation in the embodiments of the present invention is ≤80°C. Combined with a silicone-acrylic moisture-proof layer (water vapor transmission rate ≤0.5 g / m 2 / day), the present invention realizes that the photoelectric efficiency attenuation of flexible photovoltaic glass in extreme environments (-30°C) is ≤12%, and the mechanical stability (bending 1000 times at -40°C, capacitance retention rate ≥85%).

[0056] 3. The embodiments of the present invention use femtosecond laser to etch a honeycomb-shaped pore array with a diameter of 10-20 μm on the surface of the ITO layer, increasing the charge transfer area by 2 times and reducing the interface resistance to 2 Ω·cm 2 。

[0057] Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications to these embodiments once they learn the basic creative concepts. Therefore, the appended claims are intended to be construed as including the preferred embodiments and all changes and modifications falling within the scope of the present invention.

[0058] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. A method for preparing low-temperature resistant flexible photovoltaic glass, characterized in that: The following steps are involved: Step 1: Flexible glass substrate processing and conductive layer preparation The flexible glass substrate is processed by laser cleaning technology, an ITO conductive layer is deposited on the substrate surface by low-temperature plasma enhanced chemical vapor deposition, and a honeycomb pore array with a diameter of 10-20 μm is etched on the surface of the ITO layer using a femtosecond laser to form a three-dimensional charge transfer channel; Step 2: Synthesis and modification of carbon dot-modified low-temperature resistant hydrogel electrolyte ① Through the reaction of citric acid and 3-aminobenzenesulfonic acid in N,N-dimethylformamide, adding ethylenediamine and then heating under high pressure, and then ethanol precipitation, dialysis and freeze drying to obtain CD powder; ② Mix acrylamide, ammonium persulfate, N,N'-methylenebisacrylamide and a certain amount of CD powder, pour them into a mold for cross-linking, then soak them in a zinc trifluoromethanesulfonate solution, and finally dry them naturally to obtain PAM-CD hydrogel; Step 3: Assembling the multi-layer structure of photovoltaic modules ①Use the scraping method to evenly coat the PAM-CD hydrogel on the etched ITO surface to form a three-dimensional interlocking interface; ② Cover with a silicone-acrylic composite moisture-proof layer, with a silicone-acrylic mass ratio of 3:1; ③ Prepare FA0.85MA0.15PbI2.85Br0.15 mixed cation perovskite precursor solution, the solvent is DMF = 4:1, spin-coat the photovoltaic module of step ② of step 3 above in a nitrogen glove box for 30 seconds, and then anneal by solvent vapor to form a dense photoactive layer; ④ After step ③ of step three, a 100 nm gold electrode is evaporated on the surface of the photovoltaic glass, and the whole process temperature is ≤80°C to obtain flexible photovoltaic glass.

2. The preparation method according to claim 1, characterized in that The porosity of the honeycomb pore array in step 1 is 20%-50%.

3. The preparation method according to claim 1, characterized in that: In step ② of the step 2, the mass ratio of CD powder to acrylamide is 3:

100.

4. The preparation method according to claim 1, characterized in that: In step ① of step three, the thickness of the hydrogel is 300 μm, and the gel is filled into the microporous structure by vacuum infiltration.

5. The preparation method according to claim 1, characterized in that: In step ② of step 3, the thickness of the silicone-acrylic composite moisture-proof layer is 5 μm, and the water vapor transmission rate is ≤ 0.5 g / m 2 / day.

6. A low temperature resistant flexible photovoltaic glass, characterized in that: The flexible photovoltaic glass is prepared according to the preparation method described in any one of claims 1 to 5.

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