Nano-silver-doped transparent conductive adhesive and preparation method thereof

Abstract

The invention discloses a transparent conductive adhesive doped with nano-silver, and also discloses a preparation method of the transparent conductive adhesive. The preparation method of the transparent conductive adhesive comprises the following steps: preparing a polymer adhesive based on an epoxy polymer, amphoteric dispersant modified silver nanoparticles and a curing agent, and mixing the polymer adhesive with conductive microspheres to obtain the transparent conductive adhesive. Wherein in the transparent conductive adhesive, the doping amount of the amphoteric dispersant modified silver nanoparticles is 0.03-3% of the total mass of the epoxy polymer and the curing agent. The transparent conductive adhesive solves the problems that a traditional transparent conductive adhesive prepared based on Epoxy-301 is too low in conductivity and large in contact resistance with a top cell and a bottom cell, the transparent conductive adhesive can effectively reduce resistance loss, the filling factor of a silicon-based laminated cell is increased, and then the photoelectric conversion efficiency of a solar cell is improved.

Description

Technical Field

[0001] The invention relates to a nano-silver-doped transparent conductive adhesive and also relates to a preparation method of the transparent conductive adhesive. Background Art

[0002] Silicon-based tandem cell technology is expected to surpass the theoretical efficiency of single-crystal silicon cells and become the mainstream research direction in the field of solar cells. III-V / crystalline silicon tandem cells have both high efficiency and high stability, with an efficiency of 36.1% at both ends. Perovskite cells have emerged due to their low cost and simple preparation process. Currently, the photoelectric conversion efficiency of perovskite / crystalline silicon tandem cells can reach 34.6%.

[0003] There are three main ways to prepare two-terminal III-V / crystalline silicon tandem cells: epitaxial growth, wafer bonding, and mechanical stacking. Epitaxial growth is difficult to manufacture and has low efficiency due to the large differences between silicon and GaAs materials, with the highest photoelectric efficiency being only 25.9%. Although wafer bonding avoids related problems, the preparation conditions are harsh and the cost is high. The metal nanoarray bonding technology has problems such as low bonding strength and is incompatible with velvet silicon cells. For perovskite / crystalline silicon tandem cells, growing a high-quality perovskite layer on a velvet silicon substrate is also a challenge. In contrast, bonding using a transparent conductive adhesive is an important technology for achieving high-efficiency silicon-based tandem solar cells. However, the silicon-based tandem cells currently prepared using transparent conductive adhesives all have problems such as large contact resistance, severe interface electrical losses, and low device fill factors. Summary of the invention

[0004] Purpose of the invention: The purpose of the present invention is to provide a transparent conductive adhesive doped with nanosilver, which can effectively reduce the impact on the light transmittance of the device, and at the same time can effectively improve the conductivity of the transparent conductive adhesive, thereby reducing the interface resistance of the silicon-based stacked battery, reducing electrical damage, and further improving the photoelectric conversion efficiency of the silicon-based stacked battery; another purpose of the present invention is to provide a method for preparing the above-mentioned transparent conductive adhesive.

[0005] Technical solution: The nanosilver-doped transparent conductive adhesive of the present invention is firstly prepared by preparing a polymer adhesive based on epoxy polymer, silver nanoparticles modified by an amphoteric dispersant and a curing agent, and then mixing the polymer adhesive with conductive microspheres to obtain a transparent conductive adhesive; wherein, in the transparent conductive adhesive, the doping amount of the silver nanoparticles modified by the amphoteric dispersant is 0.03-3% of the total mass of the epoxy polymer and the curing agent, preferably 0.3%.

[0006] The silver nanoparticles modified by the amphoteric dispersant are prepared by the following method: silver nanoparticles are dispersed in anhydrous ethanol / isopropanol, and an amphoteric dispersant is added thereto, and after sufficient reaction (a grafting reaction can occur at room temperature), the silver nanoparticles modified by the amphoteric dispersant are obtained.

[0007] Wherein, the particle size of the silver nanoparticles is 10 to 100 nm.

[0008] The mass ratio of the amphoteric dispersant to the silver nanoparticles is about 0.04:100.

[0009] Wherein, the amphoteric dispersant is (3-mercaptopropyl)trimethoxysilane (MPS).

[0010] Wherein, the conductive microspheres are metal-coated polymethyl methacrylate (PMMA) microspheres; the particle size of the conductive microspheres is 10 to 50 μm.

[0011] The polymer adhesive is a transparent conductive polymer adhesive, and in order to enhance the transmittance of incident light, it is preferably obtained by cross-linking and curing reaction of epoxy resin Epoxy-301A and curing agent Epoxy-301B.

[0012] The method for preparing the transparent conductive adhesive comprises the following steps:

[0013] (1) adding an acetone solution containing the modified silver nanoparticles to an epoxy polymer, and after sufficient reaction at high temperature, adding a curing agent (first adding epoxy resin Epoxy-301A, and then adding curing agent Epoxy-301B); shaking and mixing evenly, and finally vacuum degassing to remove residual air in the conductive adhesive;

[0014] (2) Add the conductive microspheres into the conductive adhesive prepared above and stir evenly to obtain a transparent conductive adhesive.

[0015] Wherein, in step (1), the epoxy polymer and the curing agent are added in a mass ratio of 3 to 3.1:1.

[0016] Wherein, in step (1), the amount of modified silver nanoparticles added is 0.03-3% of the total mass of the epoxy polymer and the curing agent.

[0017] Wherein, in step (2), the ratio of the amount of conductive microspheres added to the total mass of the epoxy polymer and the curing agent is 0.093 to 0.094:1.

[0018] The reaction formula of the epoxy resin curing reaction in step (1) is:

[0019]

[0020] The reaction mechanism is as follows: the present invention uses amine salts as curing agents to undergo cross-linking reactions with epoxy resins. Since the epoxy group is a three-membered cyclic ether, the average bond angle of the ring is 60°, which is much smaller than the 109.5° bond angle of normal tetrahedral carbon or the 110° bond angle of dimethoxy in open-chain ethers, so the position of the atoms cannot allow the orbitals to have the maximum overlap. This type of bond is weaker than a general ether bond, so the epoxy group has poor stability and is easily open-ringed. Amine salts are alkaline substances and act as nucleophiles in the curing reaction, attacking the cyclic ether itself. In the above formula, Z represents an amine salt, which attacks the Cδ on the cyclic ether. + Atoms. Finally, the amine salt reacts with the monomer epoxy to form a polymer by addition reaction, and then the alkali acts to close the ring. Each active hydrogen on the amino group of the amine salt can open an epoxy group. During cross-linking and curing, the primary amine is converted into a secondary amine. In order to achieve complete curing and crystallization, the amine salt needs to be in excess of about 10%. In addition, the surface of the prepared Ag nanoparticles is only covered with a layer of -OH. Due to the different properties of the two end groups of the amphoteric dispersant, one end is hydrophilic and the other end is hydrophobic. After the hydrophobic group and the -OH group undergo a hydrolysis reaction, the hydrophilic group at the other end participates in the curing process together with the epoxy-amine system. The interfacial adhesion between the modified Ag nanoparticles and the epoxy resin matrix is ​​enhanced, and the agglomeration of the Ag nanoparticles can be effectively prevented. The curing effect of the functional groups modified on the silver nanoparticles on the epoxy resin is carried out according to the nucleophilic addition mechanism. Each active hydrogen on the group can open an epoxy group, so that it can be cross-linked and cured, and finally form a heteropolymer.

[0021] The functional groups modified on the silver nanoparticles by the amphoteric dispersant can participate in the ring-opening reaction of the epoxy resin, so that the silver nanoparticles are evenly distributed in the epoxy resin in a matrix form, which greatly improves the conductivity of the transparent conductive adhesive without affecting the light transmittance of the transparent conductive adhesive.

[0022] The use of the above-mentioned transparent conductive adhesive in the preparation of silicon-based tandem cells; wherein the tandem cells are rigid III-V group / crystalline silicon tandem solar cells, rigid perovskite / crystalline silicon tandem solar cells, flexible III-V group / crystalline silicon tandem solar cells or flexible perovskite / crystalline silicon tandem solar cells.

[0023] Beneficial effects: The transparent conductive adhesive of the present invention realizes the combination of III-V group or perovskite and textured silicon heterojunction solar cell (SHJ), and adopts textured silicon cell as the bottom cell of the stacked cell, which can effectively reduce the conductive loss, increase the fill factor (FF) of the device, and thus increase the photoelectric conversion efficiency of the solar cell; compared with the prior art, it solves the problems of low conductivity and serious electrical loss at the bonding interface of the traditional transparent conductive adhesive made based on Epoxy-301. The use of the transparent conductive adhesive of the present invention can reduce the loss of interface electrical performance without affecting the optical properties of the device, thereby obtaining III-V group / crystalline silicon stacked cells and perovskite / crystalline silicon stacked cells with higher photoelectric conversion efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the structure of a silicon-based laminated battery bonded with the transparent conductive adhesive of the present invention;

[0025] Figure 2 The volt-ampere characteristic curve of the triple-junction GaInP / AlGaAs / Si stacked solar cell based on the textured silicon heterojunction bottom cell bonded with the transparent conductive adhesive of Comparative Example 1;

[0026] Figure 3 The volt-ampere characteristic curve of a triple-junction GaInP / AlGaAs / Si stacked solar cell based on a textured silicon heterojunction bottom cell bonded with the transparent conductive adhesive of Example 1;

[0027] Figure 4 The volt-ampere characteristic curve of the triple-junction GaInP / AlGaAs / Si stacked solar cell based on textured silicon heterojunction bottom cell using the transparent conductive adhesive of Example 2;

[0028] Figure 5 The volt-ampere characteristic curve of a triple-junction GaInP / AlGaAs / Si stacked solar cell based on a textured silicon heterojunction bottom cell bonded with the transparent conductive adhesive of Example 3;

[0029] Figure 6 A schematic diagram of the structure of a perovskite / Si stacked cell bonded with the transparent conductive adhesive of the present invention;

[0030] Figure 7 The volt-ampere characteristic curve of a two-terminal perovskite / Si stacked solar cell based on a textured silicon heterojunction bottom cell prepared using the undoped transparent conductive adhesive of Comparative Example 4;

[0031] Figure 8 This is a graph showing the volt-ampere characteristic of a two-terminal perovskite / Si stacked solar cell based on a textured silicon heterojunction bottom cell and prepared using the transparent conductive adhesive of Example 2. DETAILED DESCRIPTION

[0032] like Figure 1 The figure shows a III-V / silicon heterojunction stacked solar cell made based on a transparent conductive adhesive, which includes, from top to bottom: a front metal grid electrode Au / Ag, a GaAs contact layer, a ZnS / MgF 2 Anti-reflection film, n-AlInP window layer, n-GaInP absorption layer, p-AlGaInP back field, tunnel junction, n-AlGaAs window layer, p-AlGaAs absorption layer, p-GaInP back field, p-GaAs contact layer, ITO connecting layer, transparent conductive adhesive, ITO connecting layer, silicon heterojunction bottom cell electron selection layer na-Si:H, passivation layer ia-Si:H, silicon substrate n-Si, passivation layer ia-Si:H, hole selection layer pa-Si:H and back electrode Al.

[0033] In III-V / silicon heterojunction tandem solar cells, the band gap of the GaInP absorber is 1.91 eV, the band gap of the AlGaAs absorber is 1.51 eV, and the area is 2.2×2.2 cm 2 .

[0034] Example 1

[0035] The method for preparing the transparent conductive adhesive of the present invention comprises the following steps:

[0036] (1) Add 1 mL of 1 M AgNO 3 The aqueous solution was added to 20 mL of 75 M NaCl aqueous solution, stirred evenly, and then a small amount (0.216 mg) of PVP dispersant was added, followed by 0.5 mL of 4 M NaBH 4 The aqueous solution was stirred for 5 minutes, the silver nanoparticles were collected by centrifugation, and dried at room temperature;

[0037] (2) 500 mg of silver nanoparticles were dispersed in 20 mL of anhydrous ethanol, 0.2 μL of MPS (purchased from outside, density of 1.057 g / mL) was added, and ultrasonication was performed at room temperature for 30 minutes, and then excess MPS was removed by centrifugation to obtain modified silver nanoparticles;

[0038] (3) 1000 mg of Epoxy-301A was stirred at 60° C. for 60 min to reduce its viscosity, and the acetone solution containing the modified silver nanoparticles was slowly added to the Epoxy-301A, with the added mass of the modified silver nanoparticles being controlled to be 0.3999 mg (the added amount of the modified silver nanoparticles was approximately 0.03% of the total mass of the epoxy polymer + the cured product), and stirred at 60° C. for 12 hours, and 333.3 mg of Epoxy-301B was added, and the mixture was shaken and mixed evenly, and finally vacuum degassed to remove the residual air in the obtained polymer adhesive;

[0039] (4) Take 0.125 g of silver-plated polymethyl methacrylate microspheres and add them to the polymer adhesive in step (3), stir evenly, and obtain a transparent nanosilver conductive adhesive.

[0040] Preparation of the transparent conductive adhesive prepared in Example 1 Figure 1 A III-V group / crystalline silicon stacked solar cell with a structure was prepared and its photoelectric conversion efficiency performance was tested. The test results are shown below.

[0041] Conduct performance tests on solar cells, such as Figure 3 As shown, at AM1.5G, 100mW / cm 2 Under standard light intensity irradiation, the open circuit voltage of the III-V / crystalline silicon tandem solar cell bonded with the transparent conductive adhesive (silver nanoparticle content 0.03 wt%) prepared in Example 1 was 2.99 V, and the short circuit current density was 11.46 mA / cm 2 , fill factor 76.94%, and photoelectric conversion efficiency 26.4%.

[0042] Example 2

[0043] The method for preparing the transparent conductive adhesive of the present invention comprises the following steps:

[0044] (1) Add 1 mL of 1 M AgNO 3 The aqueous solution was added to 20 mL of 75 M NaCl aqueous solution, stirred evenly, and then 0.216 mg of PVP dispersant was added, followed by 0.5 mL of 4 M NaBH 4 The aqueous solution was stirred for 5 minutes, the silver nanoparticles were collected by centrifugation, and dried at room temperature;

[0045] (2) dispersing 500 mg of silver nanoparticles into 20 mL of anhydrous ethanol, adding 0.2 μL of MPS, sonicating at room temperature for 30 minutes, and then centrifuging to remove excess MPS; obtaining modified silver nanoparticles;

[0046] (3) 1000 mg of Epoxy-301A was stirred at 60° C. for 60 min to reduce its viscosity, and the acetone solution containing the modified silver nanoparticles was slowly added to the Epoxy-301A, with the added mass of the modified silver nanoparticles being controlled to be 3.999 mg (the added amount of the modified silver nanoparticles was about 0.3% of the total mass of the epoxy polymer + the cured product), and stirred at 60° C. for 12 hours, and 333.3 mg of Epoxy-301B was added, and the mixture was shaken and mixed evenly, and finally vacuum degassed to remove the residual air in the obtained polymer adhesive;

[0047] (4) Take 0.125 g of silver-plated polymethyl methacrylate microspheres and add them to the polymer adhesive in step (3), stir evenly, and obtain a transparent nanosilver conductive adhesive.

[0048] Preparation of the transparent conductive adhesive prepared in Example 2 Figure 1 A III-V group / crystalline silicon stacked solar cell with a structure was prepared and its photoelectric conversion efficiency performance was tested. The test results are shown below.

[0049] like Figure 4 As shown, at AM1.5G, 100mW / cm 2 Under standard light intensity irradiation, the open circuit voltage of the III-V / crystalline silicon tandem solar cell bonded with the transparent conductive adhesive (silver nanoparticle content 0.3 wt%) prepared in Example 2 was 3.09 V, and the short circuit current density was 12.45 mA / cm 2 , fill factor 83.1%, and photoelectric conversion efficiency 31.9%.

[0050] Example 3

[0051] The method for preparing the transparent conductive adhesive of the present invention comprises the following steps:

[0052] (1) Add 1 mL of 1 M AgNO 3 The aqueous solution was added to 20 mL of 75 M NaCl aqueous solution, stirred evenly, and then 0.216 mg of PVP dispersant was added, followed by 0.5 mL of 4 M NaBH 4 The aqueous solution was stirred for 5 minutes, the silver nanoparticles were collected by centrifugation, and dried at room temperature;

[0053] (2) dispersing 500 mg of silver nanoparticles into 20 mL of anhydrous ethanol, adding 0.2 μL of MPS, sonicating at room temperature for 30 minutes, and then centrifuging to remove excess MPS; obtaining modified silver nanoparticles;

[0054] (3) 1000 mg of Epoxy-301A was stirred at 60° C. for 60 min to reduce its viscosity, and the acetone solution containing the modified silver nanoparticles was slowly added to the Epoxy-301A, with the added mass of the modified silver nanoparticles being controlled to be 39.999 mg (the added amount of the modified silver nanoparticles was about 3% of the total mass of the epoxy polymer + the cured product), and the mixture was stirred at 60° C. for 12 hours, and 333.3 mg of Epoxy-301B was added, and the mixture was shaken and mixed evenly, and finally vacuum degassed to remove the residual air in the obtained polymer adhesive;

[0055] (4) Take 0.125 g of silver-plated polymethyl methacrylate microspheres and add them to the polymer adhesive in step (3), stir evenly, and obtain a transparent nanosilver conductive adhesive.

[0056] Preparation of the transparent conductive adhesive prepared in Example 3 Figure 1 A III-V group / crystalline silicon stacked solar cell with a structure was prepared and its photoelectric conversion efficiency performance was tested. The test results are shown below.

[0057] like Figure 5 As shown, at AM1.5G, 100mW / cm 2 Under standard light intensity irradiation, the open circuit voltage of the III-V / crystalline silicon tandem solar cell bonded with the transparent conductive adhesive (silver nanoparticle content 3 wt%) prepared in Example 3 was 2.99 V, and the short circuit current density was 12.09 mA / cm 2 , fill factor 72%, and photoelectric conversion efficiency 26.1%.

[0058] Comparative Example 1

[0059] A method for preparing a transparent conductive adhesive not doped with silver nanoparticles comprises the following steps:

[0060] (1) 1000 mg of Epoxy-301A and 333.3 mg of Epoxy-301B were stirred at 60°C for 60 min to reduce their viscosity, and finally vacuum degassed to remove the residual air;

[0061] (2) 0.125 g of silver-plated polymethyl methacrylate (PMMA) microspheres were added to the transparent adhesive prepared above and stirred evenly to prepare a transparent conductive adhesive.

[0062] Preparation of transparent conductive adhesive prepared in Comparative Example 1 Figure 1 A III-V group / crystalline silicon stacked solar cell with a structure was prepared and its photoelectric conversion efficiency performance was tested. The test results are shown below.

[0063] like Figure 2As shown, at AM1.5G, 100mW / cm 2 Under standard light intensity irradiation, the open circuit voltage of the III-V group / crystalline silicon stacked solar cell bonded with the transparent conductive adhesive prepared in Comparative Example 1 is 2.99V, and the short circuit current density is 10.48mA / cm 2 , filling factor 75.38%, and photoelectric conversion efficiency 23.6%.

[0064] Comparative Example 2

[0065] A method for preparing a transparent conductive adhesive comprises the following steps:

[0066] (1) Add 1 mL of 1 M AgNO 3 The aqueous solution was added to 20 mL of 75 M NaCl aqueous solution, stirred evenly, and then 0.216 mg of PVP dispersant was added, followed by 0.5 mL of 4 M NaBH 4 The aqueous solution was stirred for 5 minutes, the silver nanoparticles were collected by centrifugation, and dried at room temperature;

[0067] (2) dispersing 500 mg of silver nanoparticles into 20 mL of anhydrous ethanol, adding 0.2 μL of APTES, sonicating at room temperature for 30 minutes, and then centrifuging to remove excess APTES to obtain modified silver nanoparticles;

[0068] (3) 1000 mg of Epoxy-301A was stirred at 60° C. for 60 min to reduce its viscosity, and the acetone solution containing the modified silver nanoparticles was slowly added to the Epoxy-301A, with the added mass of the modified silver nanoparticles being controlled to be 3.999 mg (the added amount of the modified silver nanoparticles was about 0.3% of the total mass of the epoxy polymer + the cured product), and stirred at 60° C. for 12 hours, and 333.3 mg of Epoxy-301B was added, and the mixture was shaken and mixed evenly, and finally vacuum degassed to remove the residual air in the obtained polymer adhesive;

[0069] (4) Take 0.125 g of silver-plated polymethyl methacrylate microspheres and add them to the polymer adhesive in step (3), stir evenly, and obtain a transparent nanosilver conductive adhesive.

[0070] Preparation of transparent conductive adhesive prepared in Comparative Example 2 Figure 1 A III-V group / crystalline silicon stacked solar cell with a structure was prepared and its photoelectric conversion efficiency performance was tested. The test results are shown below.

[0071] In AM1.5G, 100mW / cm 2Under standard light intensity irradiation, the open circuit voltage of the III-V group / crystalline silicon stacked solar cell bonded with the transparent conductive adhesive prepared in Comparative Example 2 is 2.99V, and the short circuit current density is 11.48mA / cm 2 , fill factor 76.6% and efficiency 26.3%.

[0072] Comparative Example 3

[0073] A method for preparing a transparent conductive adhesive comprises the following steps:

[0074] (1) Add 1 mL of 1 M AgNO 3 The aqueous solution was added to 20 mL of 75 M NaCl aqueous solution, stirred evenly, and then 0.216 mg of PVP dispersant was added, followed by 0.5 mL of 4 M NaBH 4 The aqueous solution was stirred for 5 minutes, the silver nanoparticles were collected by centrifugation, and dried at room temperature;

[0075] (2) dispersing 500 mg of silver nanoparticles into 20 mL of anhydrous ethanol, adding 0.02 μL of MPS, and ultrasonicating at room temperature for 30 minutes to obtain modified silver nanoparticles;

[0076] (3) 1000 mg of Epoxy-301A was stirred at 60° C. for 60 min to reduce its viscosity, and the acetone solution containing the modified silver nanoparticles was slowly added to the Epoxy-301A, with the added mass of the modified silver nanoparticles being controlled to be 3.999 mg (the added amount of the modified silver nanoparticles was about 0.3% of the total mass of the epoxy polymer + the cured product), and stirred at 60° C. for 12 hours, and 333.3 mg of Epoxy-301B was added, and the mixture was shaken and mixed evenly, and finally vacuum degassed to remove the residual air in the obtained polymer adhesive;

[0077] (4) Take 0.125 g of silver-plated polymethyl methacrylate microspheres and add them to the polymer adhesive in step (3), stir evenly, and obtain a transparent nanosilver conductive adhesive.

[0078] Preparation of transparent conductive adhesive prepared in Comparative Example 3 Figure 1 A III-V group / crystalline silicon stacked solar cell with a structure was prepared and its photoelectric conversion efficiency performance was tested. The test results are shown below.

[0079] In AM1.5G, 100mW / cm 2 Under standard light intensity irradiation, the open circuit voltage of the III-V group / crystalline silicon stacked solar cell bonded with the transparent conductive adhesive prepared in Comparative Example 3 was 2.79 V, and the short circuit current density was 10.8 mA / cm 2 , fill factor 75.5% and efficiency 22.7%.

[0080] like Figure 6 The figure shows a perovskite / silicon heterojunction stacked solar cell made based on a transparent conductive adhesive, which includes, from top to bottom: a front metal grid electrode Au / Ag, an ITO electrode, a perovskite cell electron transport layer SnO 2 , perovskite active layer, perovskite cell hole transport layer Spiro-OMeTAD, MoOx buffer layer, ITO connecting layer, transparent conductive adhesive, ITO connecting layer, silicon heterojunction bottom cell electron selection layer na-Si:H, passivation layer ia-Si:H, silicon substrate n-Si, passivation layer ia-Si:H, hole selection layer pa-Si:H and back electrode Al.

[0081] In the perovskite / silicon heterojunction tandem solar cell, the band gap of the perovskite absorber is 1.68 eV and the area is 1×1 cm 2 .

[0082] Example 4

[0083] Preparation of transparent conductive adhesive prepared in Example 2 Figure 6 A perovskite / silicon heterojunction stacked solar cell with a structure was produced and its photoelectric conversion efficiency performance was tested. The test results are shown below.

[0084] like Figure 8 As shown, at AM1.5G, 100mW / cm 2 Under standard light intensity of , the open circuit voltage of the transparent conductive adhesive bonded perovskite / crystalline silicon tandem solar cell prepared in Example 2 was 1.928V, and the short circuit current density was 18.62mA / cm 2 , fill factor 84.3%, and photoelectric conversion efficiency 30.3%.

[0085] Comparative Example 4

[0086] Preparation of transparent conductive adhesive prepared in Comparative Example 1 Figure 6 A perovskite / silicon heterojunction stacked solar cell with a structure was produced and its photoelectric conversion efficiency performance was tested. The test results are shown below.

[0087] like Figure 7 As shown, at AM1.5G, 100mW / cm 2 Under standard light intensity, the open circuit voltage of the perovskite / crystalline silicon tandem solar cell in Comparative Example 4, which is not bonded with a transparent conductive adhesive, is 1.82V, and the short circuit current density is 18.54mA / cm 2 , fill factor 74.1% and efficiency 25.0%.

[0088] The present invention solves the problem that the conductivity of the traditional transparent conductive adhesive made based on Epoxy-301 is too low and the contact resistance with the top and bottom cells is large. The present invention can effectively reduce the resistance loss, increase the filling factor of the stacked battery, and thus increase the photoelectric conversion efficiency of the solar cell.

Claims

1. A transparent conductive adhesive doped with nanosilver, characterized in that: A polymer adhesive is first prepared based on epoxy polymer, silver nanoparticles modified by an amphoteric dispersant and a curing agent, and then the polymer adhesive is mixed with conductive microspheres to obtain a transparent conductive adhesive; wherein the doping amount of the silver nanoparticles modified by the amphoteric dispersant in the transparent conductive adhesive is 0.03-3% of the total mass of the epoxy polymer and the curing agent.

2. The transparent conductive adhesive according to claim 1, characterized in that: In the transparent conductive adhesive, the doping amount of the silver nanoparticles modified by the amphoteric dispersant is 0.3% of the total mass of the epoxy polymer and the curing agent.

3. The transparent conductive adhesive according to claim 1, characterized in that: The silver nanoparticles modified by the amphoteric dispersant are prepared by the following method: silver nanoparticles are dispersed in anhydrous ethanol / isopropanol, and the amphoteric dispersant is added thereto, and after sufficient reaction, the silver nanoparticles modified by the amphoteric dispersant are obtained.

4. The transparent conductive adhesive according to claim 2, characterized in that: The particle size of the silver nanoparticles is 10-100 nm.

5. The transparent conductive adhesive according to claim 2, characterized in that: The mass ratio of the amphoteric dispersant to the silver nanoparticles is not less than 0.04:

100.

6. The transparent conductive adhesive according to claim 2, characterized in that: The amphoteric dispersant is (3-mercaptopropyl)trimethoxysilane.

7. The method for preparing the transparent conductive adhesive according to claim 1, characterized in that: The steps include: (1) adding an acetone solution containing the modified silver nanoparticles to an epoxy polymer, and after sufficient reaction at high temperature, adding a curing agent thereto; shaking and mixing the mixture evenly, and vacuum degassing to remove the residual air in the obtained polymer adhesive; (2) Add the conductive microspheres into the prepared polymer adhesive and stir evenly to obtain a transparent conductive adhesive.

8. The preparation method according to claim 7, characterized in that: In step (1), the mass ratio of the epoxy polymer to the curing agent is 3 to 3.1:

1.

9. The preparation method according to claim 7, characterized in that: In step (1), the amount of modified silver nanoparticles added is 0.03-3% of the total mass of the epoxy polymer and the curing agent.

10. The preparation method according to claim 7, characterized in that: In step (2), the ratio of the amount of conductive microspheres added to the total mass of the epoxy polymer and the curing agent is 0.093 to 0.094:1.

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