Organic solar cell taking ternary composite material as hole transport layer

Abstract

The invention discloses an organic solar cell with a ternary composite material as a hole transport layer. The organic solar cell sequentially comprises an anode substrate, the hole transport layer, an organic active layer, an electron transport layer and a cathode layer from bottom to top, the material of the hole transport layer is a ternary composite hole transport material obtained by gold nano bipyramid, hexadecyl trimethyl ammonium chloride and PEDOT: PSS through ionic bond action, the sedimentation problem is solved, and meanwhile, the charge recombination loss is inhibited by improving the conductivity and promoting exciton dissociation and transport, so that the hole transport efficiency is improved. And the photoelectric conversion efficiency of the organic solar cell is obviously improved.

Description

Technical Field

[0001] The present invention relates to the field of solar cells, and particularly to an organic solar cell with a ternary composite material as a hole transport layer. Background Art

[0002] Under the background of "dual carbon", photovoltaic technology has received unprecedented attention, and the traditional crystalline silicon solar cell industry has developed rapidly. The preparation of silicon solar cells has the disadvantages of high energy consumption and complex processes, and in addition, its own poor flexibility and other disadvantages have greatly limited its application in many fields. Compared with silicon solar cells, emerging organic solar cells have many advantages such as low preparation cost, bend resistance, large-area printing and processing, color tunability, and portability, and are favored by scientists. It is expected to become the next generation of emerging photovoltaic technology, forming complementary advantages with silicon solar cells. Thanks to the continuous optimization of material preparation and device structure, the power conversion efficiency (PCE) of organic solar cells (OSCs) has been rapidly improved, and multiple research teams have reported single-junction OSCs with a PCE exceeding 19%.

[0003] In order to further improve the PCE of OSCs, in addition to vigorously developing new OSC active materials, designing and preparing interfacial layer materials that integrate charge transport and collection functions is also crucial for improving the PCE. Among many hole transport layer (HTL) materials, commercial poly(3,4-ethylenedioxythiophene):poly(styrenesulfonic acid) (PEDOT:PSS, Al4083) dominates due to its advantages such as aqueous solution processability, good film-forming property, high work function, and high transmittance. Constructing a binary composite system based on PEDOT:PSS (Al4083) by physical doping (such as doping carbon nanomaterials, MXene, etc.) has been proven to be an effective way to improve the interfacial layer performance, thereby improving the performance of many electronic devices such as organic solar cells and perovskite solar cells.

[0004] The advantage of physical doping is simple and easy to implement, but the disadvantage is that nanoparticles are prone to sedimentation or aggregation in the PEDOT:PSS (Al4083) solution, and the dispersion uniformity of the particles cannot be controlled after being prepared into a film, resulting in a low yield and poor repeatability of organic solar cell devices. Summary of the Invention

[0005] The present invention provides an organic solar cell with a ternary composite material as a hole transport layer. By constructing a stable ternary composite system, while solving the sedimentation problem, the power conversion efficiency of the organic solar cell is significantly improved by enhancing the conductivity, promoting exciton dissociation and transport, and suppressing charge recombination loss.

[0006] To solve this technical problem, the present invention provides the following technical solutions:

[0007] An organic solar cell with a ternary composite material as the hole transport layer, which sequentially includes an anode substrate, a hole transport layer, an organic active layer, an electron transport layer, and a cathode layer from bottom to top; the material of the hole transport layer is a ternary composite hole transport material obtained by the ionic bond action of gold nanobipyramids, cetyltrimethylammonium chloride, and PEDOT:PSS.

[0008] In this system, as a cationic surfactant, cetyltrimethylammonium chloride (CTAC) can, on the one hand, disperse and stabilize gold nanobipyramids through the interaction between ions; on the other hand, CTAC can interact with the negatively charged PSS in PEDOT:PSS and bind firmly together through the Coulomb force between positive and negative charges; thus, a stable PEDOT:PSS-CTAC-gold nanobipyramid ternary system is formed. In addition, as a surfactant, CTAC can improve the wettability of the solution and also open the chains of PSS through the interaction between ions, exposing more PEODT, and synergistically with gold nanobipyramids, improve the conductivity of the ternary system by increasing the contact between PEDOTs; as a metal nanoparticle with high conductivity, the introduction of gold nanobipyramids itself can further improve the conductivity of the ternary system. The construction of a stable system can solve the sedimentation problem, thus bringing a better device yield; the improvement of wettability can simplify the process and eliminate the need for Plasma or ozone treatment of the substrate during preparation; the improvement of conductivity can improve the hole collection and transport efficiency of the interface layer.

[0009] Preferably, the preparation method of the above-mentioned hole transport layer includes the following steps:

[0010] S1. Prepare gold nanobipyramids and disperse them in a CTAC solution to obtain a gold nanobipyramid dispersion;

[0011] S2. Add the gold nanobipyramid dispersion prepared in step S1 to the PEDOT:PSS solution, stir and react at room temperature for 12 hours to obtain a stable and uniform ternary system mixture material; the hole transport layer is obtained through spin coating and annealing.

[0012] Furthermore, in the above step S1, the specific preparation process of the gold nanobipyramid dispersion is as follows: under high-speed stirring, 4 mL of 2.5 mM HAuCl4 aqueous solution is added to 5 mL of an aqueous solution containing 56 mM CTAC and 6 mM citric acid, and then 1 mL of a freshly prepared 25 mM NaBH4 ice water solution is quickly added, and then stirred for 2 minutes, the color of the solution will turn brown, and then it is placed in an 80°C oil bath for reaction for 15 hours, the color turns red, and the gold seed solution is prepared and stored at room temperature for use;

[0013] Add the prepared gold seed solution to 10 mL of 10 mM HAuCl4, 2 mL of 10 mM AgNO3, 10 mL of 1.0 M HCl, 1.8 mL of 0.1 M Vc, and 200 mL of 0.1 M CTAC growth solution, and stir slowly for 2 min to mix evenly;

[0014] Finally, the mixture was placed in a 30°C water bath for 12 hours. Within the first 15 minutes, the color of the solution gradually changed and eventually turned dark green. After the prepared gold nanobipyramids were allowed to stand for 12 hours, they were centrifuged once to disperse the precipitate in water, and then centrifuged again and 6.67 mL of CTAC was added for standby use.

[0015] Furthermore, in the above step S2, the gold nanobipyramid dispersion is added to the PEDOT:PSS solution for reaction, wherein the volume percentage of the gold nanobipyramid dispersion is 0%-2%, the mixed solution is stirred sufficiently to form a uniform and stable ternary system, and after filtering through a filter with a pore size of 0.45 microns, the above solution is spin-coated on the surface of the treated anode substrate at a speed of 3000-4500 rpm for 40-60 seconds; the spin-coated anode substrate is annealed at a temperature of 120-150° C. for 10-15 minutes.

[0016] Preferably, the hole transport layer has a thickness of 20-30 nm, preferably 25 nm.

[0017] Preferably, the anode substrate is selected from indium tin oxide glass ITO.

[0018] Preferably, the organic active layer material is PM6:Y6, and the thickness of the active layer is 90-120 nm, preferably 100 nm.

[0019] The active layer is a classic active layer material of an organic solar cell, such as P3HT:ICBA, PM6:Y6, etc. The present invention takes PM6:Y6 as an example, and the thickness of the active layer is 90-120 nm, preferably 100 nm.

[0020] The material of the electron transport layer is PDINO, and the thickness of the electron transport layer is 50 - 70 nm; preferably 60 nm.

[0021] The cathode layer is Ag or Cu, and the thickness of the cathode layer is 60 - 80 nm; preferably 70 nm.

[0022] This solution also provides a preparation method of the above-mentioned organic solar cell with a ternary composite material as the hole transport layer, including the following steps:

[0023] S1. Clean the anode substrate and treat the surface of the anode layer of the anode substrate.

[0024] S2. Spin-coat the hole transport layer on the anode layer treated in step S1.

[0025] S3. Spin-coat the organic active layer on the hole transport layer treated in step S2.

[0026] S4. Spin-coat the electron transport layer on the surface of the organic active layer prepared in step S3, and evaporate and deposit the cathode layer.

[0027] Preferably, in the above step S1, the cleaning of the anode substrate includes: ultrasonically cleaning the ITO glass with dish soap, deionized water, acetone, and isopropanol for 25 - 35 minutes in sequence; after drying with nitrogen, performing surface plasma treatment on the surface of the anode substrate with a Plasma cleaner for 1 - 2 minutes.

[0028] For the ternary system hole transport material constructed in the present invention, due to the improvement of the solution wettability by CTAC, Plasma treatment is no longer required.

[0029] Preferably, in the above step S3, the organic active layer of the organic solar cell is PM6:Y6, the mass ratio of PM6 and Y6 is 1:1.2, the solvent used is ultra-dry chloroform, and then the prepared solution is spin-coated on the PEDOT:PSS layer at a speed of 4000 rpm; in the above step S4, the material of the electron transport layer is PDINO, and after the active layer, a methanol solution with a concentration of 1.0 mg / mL PDINO is spin-coated and deposited on the active layer at a speed of 3000 rpm for 30 seconds to obtain the electron transport layer; the metal cathode Al, Ag or Cu is physically vapor-deposited to form the cathode layer in a vacuum of ~10 -4 Pa to obtain the organic solar cell.

[0030] Compared with the prior art, the present invention has the following advantages:

[0031] The present invention constructs a novel ternary system hole transport material based on gold nanobipyramids, cetyltrimethylammonium chloride (CTAC), and PEDOT:PSS (Al4083) through ionic bond interactions. First, by introducing CTAC and gold nanobipyramids, the gold nanobipyramids are uniformly dispersed in the hole transport layer. At the same time, the conductivity of the hole transport layer is increased, the charge collection and transport efficiency of the interface layer are improved, and the non-radiative recombination energy loss of the device is reduced, thereby achieving the purpose of improving the photoelectric conversion efficiency of the device. Second, the plasmonic light scattering and near-field coupling effects brought by the gold nanobipyramids enhance the light transmittance of the interface layer, allowing more sunlight to pass through the hole transport layer to reach the active layer and enhancing the absorption of sunlight. Third, the introduction of the surfactant material CTAC eliminates the need for Plasma or ozone cleaning treatment of the substrate during the spin-coating process of the hole transport layer, simplifying the device fabrication process. Finally, the combination of the ternary system components through ionic bond attraction not only improves the stability of the material but also solves the key problem of component sedimentation.

[0032] In the present invention, through the synergistic effect among the above three components, the short-circuit current density of the device can be increased from 25.47 mA / cm 2 to 26.42 mA / cm 2 , the fill factor is increased from 67.78% to 69.12%, and the photoelectric conversion efficiency of the device is increased from 14.82% to 15.47%. In addition, the yield of the device has also been greatly improved, further demonstrating the good stability of the system and the uniformity of the component distribution on the surface.

[0033] Compared with ordinary binary doping systems, the newly constructed ternary material exhibits better stability without sedimentation. Compared with the traditional hole transport layer material PEDOT:PSS (Al4083), the newly constructed ternary material exhibits higher conductivity and better sunlight transmission ability, thus increasing the short-circuit current density and fill factor of the solar cell device. In addition, the improvement of solution wettability also simplifies the device fabrication process, and the result of the multi-component synergistic effect also greatly improves the photoelectric conversion efficiency of the solar cell. Description of the Drawings

[0034] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, form a part of this application, and do not limit the embodiments of the present invention. In the drawings:

[0035] Figure 1 is the preparation process of the PEDOT:PSS / gold nanobipyramid / CTAC ternary system and the organic solar cell;

[0036] Figure 2 is the schematic diagram of the organic solar cell device structure;

[0037] Figure 3 It is the current density-voltage characteristic curve graph of the organic solar cells provided in Example 1 and Comparative Example 1. Detailed implementation manners

[0038] To make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with embodiments. The illustrative implementation manners of the present invention and their descriptions are only used to explain the present invention and are not used to limit the present invention.

[0039] Example 1

[0040] As Figure 1-2 shown, this example provides an organic solar cell with a ternary system of PEDOT:PSS / gold nanobipyramid / CTAC stable structure as the hole transport layer, and on this basis, an organic solar cell with a device structure of ITO / PEDOT:PSS-gold nanobipyramid-CTAC / PM6:Y6 / PDINO / Ag is prepared. Figure 2 It is a schematic diagram of the device structure of the organic solar cell. The device structure includes an anode substrate, a hole transport layer, an organic active layer, an electron transport layer, and a cathode layer from bottom to top. Figure 1 Shown is the preparation process of the PEDOT:PSS / gold nanobipyramid / CTAC ternary system and the organic solar cell. The preparation process flow is as follows:

[0041] Step 1: Under high-speed stirring, add 4 mL of 2.5 mM HAuCl4 aqueous solution to 5 mL of an aqueous solution containing 56 mM CTAC and 6 mM citric acid, and then quickly add a freshly prepared ice aqueous solution of NaBH4 (25 mM, 1 mL). Stir for another 2 min, and the color of the solution will turn brown. Then place it in an oil bath at 80 °C and react for 15 h. The color turns red. The prepared gold seed solution is stored at room temperature for later use. Add the prepared gold seed solution to a growth solution of 10 ml HAuCl4 (10 mM), 2 mL AgNO3 (10 mM), 10 mL HCl (1.0 M), 1.8 mL Vc (0.1 M), and 200 mL CTAC (0.1 M), and slowly stir for 2 min to mix evenly. Finally, place the above mixture in a water bath at 30 °C and let it stand for 12 h. Within the first 15 min, the color of the solution gradually changes and finally turns dark green. After the prepared gold nanobipyramids are left standing for 12 h, centrifuge once to disperse the precipitate in water, and then centrifuge again and add 6.67 mL of CTAC for later use.

[0042] Step 2: Add the CTAC solution of gold nanobipyramids into the PEDOT:PSS (Al4083) solution, where the volume percentage of the CTAC solution of gold nanobipyramids is 1%, and react at room temperature for 12 hours until a homogeneous and stable ternary system solution is produced;

[0043] Step 3: The cleaning of the anode substrate includes: ultrasonically cleaning the ITO glass with dishwashing liquid, deionized water, acetone, and isopropanol in sequence for 25 - 35 minutes each for standby.

[0044] Step 4: Dry the anode substrate with nitrogen. After filtering the ternary system solution through a filter with a pore size of 0.45 μm, spin - coat the above - mentioned solution on the anode substrate at a speed of 3500 rpm for 40 - 60 s; anneal the spin - coated anode substrate at a temperature of 140 °C for 15 minutes.

[0045] Step 5: The active layer of the organic solar cell adopts the currently most popular PM6:Y6 system, with a mass ratio of 1:1.2, the solvent used is ultra - dry chloroform, and the total concentration is 17.6 mg / ml. Stir the prepared solution for 6 hours, and then spin - coat it on the PEDOT:PSS layer at a speed of 4000 rpm.

[0046] Step 6: Dissolve 5 mg of PDINO in 5 ml of methanol to prepare a PDINO methanol solution with a concentration of 1.0 mg / mL, and then spin - coat and deposit it on the active layer PM6:Y6 at a speed of 3000 rpm for 30 s to obtain an electron - transport layer.

[0047] Step 7: The metal cathode Ag is physically vapor - deposited under a mask in a vacuum of ~10 -4 Pa to obtain an organic solar cell.

[0048] Example 2

[0049] A ternary system composed of PEDOT:PSS, gold nanobipyramids, and CTAC is used as the hole - transport layer, and on this basis, an organic solar cell with a device structure of ITO / PEDOT:PSS - gold nanobipyramid - CTAC / PM6:Y6 / PDINO / Ag is fabricated (as Figure 2 shown). As Figure 1 shown, its preparation process flow is as follows:

[0050] Step 1: Under high-speed stirring, add 4 mL of 2.5 mM HAuCl4 to 5 mL of an aqueous solution containing 56 mM CTAC and 6 mM citric acid. Then, quickly add a freshly prepared ice-cold aqueous solution of NaBH4 (25 mM, 1 mL), and stir for another 2 min. The color of the solution will turn brown, and then place it in an oil bath at 80 °C for 15 h. The color changes to red, and the seed solution is stored at room temperature for later use. Add the prepared seed solution to the growth solution containing 10 ml of HAuCl4 (10 mM), 2 mL of AgNO3 (10 mM), 10 mL of HCl (1.0 M), 1.8 mL of Vc (0.1 M), and 200 mL of CTAC (0.1 M), and stir slowly for 2 min to mix evenly. Finally, place the above mixture in a water bath at 30 °C and let it stand for 12 h. Within the first 15 min, the color of the solution gradually changes and finally turns dark green. After standing the prepared gold nanobipyramids for 12 h, centrifuge once to disperse the precipitate in water, and then centrifuge again and add 6.67 mL of CTAC for use.

[0051] Step 2: Add the CTAC solution of gold nanobipyramids to the PEDOT:PSS (Al4083) solution, where the volume percentage of the CTAC solution of gold nanobipyramids is 2%, and react at room temperature for 12 hours to form a uniform and stable ternary system.

[0052] Step 3: The cleaning of the anode substrate includes: ultrasonically cleaning the ITO glass with dish soap, deionized water, acetone, and isopropanol for 25 - 35 minutes each in sequence for later use.

[0053] Step 4: Dry the anode substrate with nitrogen. After filtering the ternary system solution through a 0.45 - micron pore size filter, spin - coat the above solution on the anode substrate at a speed of 3500 rpm for 40 - 60 s; perform annealing treatment on the spin - coated anode substrate at a temperature of 140 °C for 15 minutes.

[0054] Step 5: The active layer of the organic solar cell adopts the currently most popular PM6:Y6 system, with a mass ratio of 1:1.2 between the two. The solvent used is ultra - dry chloroform, and the total concentration is 17.6 mg / ml. Stir the prepared solution for 6 hours, and then spin - coat it on the PEDOT:PSS layer at a speed of 4000 rpm.

[0055] Step 6: Dissolve 5 mg of PDINO in 5 ml of methanol to prepare a PDINO methanol solution with a concentration of 1.0 mg / mL, and then spin - coat and deposit it on the active layer PM6:Y6 at a speed of 3000 rpm for 30 s to obtain an electron transport layer.

[0056] Step 7: The metal cathode Ag is deposited under a mask template at ~10 -4Physical vapor deposition is carried out in a vacuum of [[Pa]] to obtain an organic solar cell.

[0057] Comparative Example 1

[0058] Using PEDOT:PSS(Al4083) as the hole transport material, the device structure is constructed as:

[0059] An organic solar cell of ITO / PEDOT:PSS / PM6:Y6 / PDINO / Ag. The preparation process flow is as follows:

[0060] Step 1. The cleaning of the anode substrate includes: successively ultrasonic cleaning the ITO glass with dishwashing liquid, deionized water, acetone, and isopropanol for 25 - 35 minutes each and waiting for use.

[0061] Step 2. Dry the anode substrate with nitrogen, and then use the plasma generated by a Plasma cleaner to clean the residual organic substances on the ITO surface, etc., while increasing the work function of the ITO surface. After filtering the PEDOT:PSS(Al4083) solution through a 0.45 - micron pore diameter filter, spin - coat the above solution on the anode substrate at a speed of 3500 rpm for 40 - 60 s; anneal the spin - coated anode substrate at a temperature of 140 °C for 15 minutes.

[0062] Step 3. The active layer of the organic solar cell adopts the currently most popular PM6:Y6 system, with a mass ratio of 1:1.2 between the two. The solvent used is ultra - dry chloroform, and the total concentration is 17.6 mg / ml. Stir the prepared solution for 6 hours, and then spin - coat it on the PEDOT:PSS layer at a speed of 4000 rpm.

[0063] Step 4. Dissolve 5 mg of PDINO in 5 ml of methanol to prepare a PDINO methanol solution with a concentration of 1.0 mg / mL, and then spin - coat and deposit it on the active layer PM6:Y6 at a speed of 3000 rpm for 30 s to obtain an electron transport layer.

[0064] Step 5. Metal cathode Ag is subjected to physical vapor deposition in a vacuum of ~10 -4 Pa to obtain an organic solar cell.

[0065] Comparative Example 2

[0066] Using a binary system composed of PEDOT:PSS and CTAC components as the hole transport layer, and on this basis, an organic solar cell with a device structure of ITO / PEDOT:PSS - CTAC / PM6:Y6 / PDINO / Ag is prepared. The preparation process flow is as follows:

[0067] Step 1: Add 56 mM CTAC solution to the PEDOT:PSS (Al4083) solution, where the volume percentage of the CTAC solution is 1%. Stir at room temperature for 12 hours until a homogeneous and stable binary system is formed.

[0068] Step 2: The cleaning of the anode substrate includes: ultrasonically cleaning the ITO glass with dishwashing liquid, deionized water, acetone, and isopropanol in sequence for 25 - 35 minutes each and waiting for use.

[0069] Step 3: Dry the anode substrate with nitrogen. After filtering the solution through a 0.45 - micron pore size filter, spin - coat the above - mentioned solution on the anode substrate at a speed of 3500 rpm for 40 - 60 s; anneal the spin - coated anode substrate at a temperature of 140 °C for 15 minutes.

[0070] Step 4: The active layer of the organic solar cell adopts the currently most popular PM6:Y6 system, with a mass ratio of 1:1.2 between the two. The solvent used is ultra - dry chloroform, and the total concentration is 17.6 mg / ml. Stir the prepared solution for 6 hours, and then spin - coat it on the PEDOT:PSS layer at a speed of 4000 rpm.

[0071] Step 5: Dissolve 5 mg of PDINO in 5 ml of methanol to prepare a PDINO methanol solution with a concentration of 1.0 mg / mL, and then spin - coat and deposit it on the active layer PM6:Y6 at a speed of 3000 rpm for 30 s to obtain the electron transport layer.

[0072] Step 6: Physical vapor deposition of the metal cathode Ag is carried out under a vacuum of ~10 -4 Pa to obtain the organic solar cell.

[0073] Comparative Example 3

[0074] This example provides an organic solar cell with a PEDOT:PSS / gold nanobipyramid binary composite material as the hole - transport layer, and on this basis, an organic solar cell with a device structure of ITO / PEDOT:PSS - gold nanobipyramid / PM6:Y6 / PDINO / Ag is prepared. Its preparation process flow is as follows:

[0075] Step 1: Under high-speed stirring, add 4 mL of 2.5 mM HAuCl4 to 5 mL of an aqueous solution containing 6 mM citric acid. Then quickly add a freshly prepared ice-cold aqueous solution of NaBH4 (25 mM, 1 mL), and stir for another 2 min. The color of the solution will turn brown, and then place it in an oil bath at 80 °C for 15 h. The color changes to red, and the prepared gold seed solution is stored at room temperature for later use. Add the prepared gold seed solution to the growth solution of 10 mL of HAuCl4 (10 mM), 2 mL of AgNO3 (10 mM), 10 mL of HCl (1.0 M), and 1.8 mL of Vc (0.1 M), and stir slowly for 2 min to mix evenly. Finally, place the above mixture in a water bath at 30 °C and let it stand for 12 h. Within the first 15 min, the color of the solution gradually changes and finally turns black-green. After standing the prepared gold nanobipyramids for 12 h, centrifuge once and disperse the precipitate in water.

[0076] Step 2: Incorporate the gold nanobipyramid solution into the PEDOT:PSS (Al4083) solution, where the volume percentage of the gold nanobipyramid solution is 1%, and stir the mixed solution well.

[0077] The cleaning of the anodic substrate includes: successively ultrasonically clean the ITO glass with dishwashing liquid, deionized water, acetone, and isopropanol for 25 - 35 minutes each for later use.

[0078] Dry the anodic substrate with nitrogen. After filtering the solution through a filter with a pore size of 0.45 microns, spin-coat the above solution on the anodic substrate at a speed of 3500 rpm for 40 - 60 s; perform annealing treatment on the spin-coated anodic substrate at a temperature of 140 °C for 15 minutes.

[0079] The active layer of the organic solar cell adopts the currently most popular PM6:Y6 system, with a mass ratio of 1:1.2 between the two. The solvent used is ultradry chloroform, and the total concentration is 17.6 mg / ml. Stir the prepared solution for 6 hours, and then spin-coat it on the PEDOT:PSS layer at a speed of 4000 rpm.

[0080] Dissolve 5 mg of PDINO in 5 ml of methanol to prepare a PDINO methanol solution with a concentration of 1.0 mg / mL, and then spin-coat and deposit it on the active layer PM6:Y6 at a speed of 3000 rpm for 30 s to obtain the electron transport layer.

[0081] Step 7: The metal cathode Ag is physically vapor deposited under a vacuum of ~10 -4 Pa to obtain the organic solar cell.

[0082] The parameter comparisons between Example 1-2 and Comparative Example 1 are shown in Table 1. It can be found from Table 1 that the short-circuit current density (Jsc) of Example 1 increased from 25.47 mA / cm2 to 26.42 mA / cm2, and the fill factor increased from 67.78% to 69.12%. When adding gold nanobipyramids alone to PEDOT:PSS (4083), the efficiency increased to 14.91%. When adding CTAC alone, the efficiency could be increased to 15.20%. The ternary complex formed by the synergistic effect of the two could increase the efficiency to 15.47%. This shows that doping PEDOT:PSS with gold nanobipyramids improves the hole transport ability of PEDOT:PSS and promotes the light trapping ability of the active layer, thereby increasing the short-circuit current density, and thus increasing the energy conversion efficiency from 14.82% to 15.47%. From the data of Example 1-2, it can be seen that as the addition concentration of PEDOT:PSS increases, when it is greater than a certain doping amount, the effect becomes worse. This indicates that appropriate doping can improve the conductivity of PEDOT:PSS and improve its interfacial interaction with the active layer, resulting in improved carrier extraction, transport and collection efficiency, increased short-circuit current density and fill factor. However, excessive doping may damage the film formation of PEDOT:PSS, which is not conducive to forming a smooth and defect-free surface, resulting in a decrease in device efficiency.

[0083] Table 1

[0084]

[0085]

[0086] Figure 3 Figure showing the relationship between current density and voltage of the organic solar cell with AuNCs-doped PEDOT:PSS as the hole transport layer in Example 1 and the organic solar cell with PEDOT:PSS as the hole transport layer in Comparative Example 1; from the appendix Figure 3 It can be seen that for the solar cell with PEDOT:PSS as the hole transport layer in Comparative Example 1, its open-circuit voltage (Voc) is 0.84 V, the short-circuit current density (Jsc) is 25.47 mA / cm2, and the fill factor (FF) is 67.78%. For the organic solar cell with gold nanobipyramid-doped PEDOT:PSS as the hole transport layer in Example 1, its open-circuit voltage (Voc) is 0.84 V, the short-circuit current density (Jsc) is 26.42 mA / cm 2 , and the fill factor (FF) is 69.12%. This shows that the introduction of gold nanobipyramids can effectively improve the hole extraction, transport and collection efficiency, and promote the light absorption of the active layer, thereby increasing the device short-circuit current density and fill factor.

[0087] The specific embodiments described above further elaborate on the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only for the specific embodiments of the present invention and is not intended to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. An organic solar cell with a ternary composite material as the hole transport layer, characterized in that, It sequentially includes an anode substrate, a hole transport layer, an organic active layer, an electron transport layer, and a cathode layer from bottom to top; the material of the hole transport layer is a ternary composite hole transport material obtained by ionic bonding of gold nanobipyramids, cetyltrimethylammonium chloride, and PEDOT:PSS.

2. The organic solar cell using a ternary composite material as a hole transport layer according to claim 1, wherein, The preparation method of the hole transport layer includes the following steps: S1. Prepare gold nanobipyramids and disperse them in a CTAC solution to obtain a gold nanobipyramid dispersion; S2. Add the gold nanobipyramid dispersion prepared in step S1 to a PEDOT:PSS solution, stir and react at room temperature for 12 hours to obtain a stable and uniform ternary system mixture material; the hole transport layer is obtained through spin coating and annealing.

3. The organic solar cell with a ternary composite material as the hole transport layer according to claim 2, characterized in that, In step S1, the specific preparation process of the gold nanobipyramid dispersion is as follows: Under high-speed stirring, add 4 mL of 2.5 mM HAuCl4 aqueous solution to 5 mL of an aqueous solution containing 56 mM CTAC and 6 mM citric acid, then quickly add 1 mL of freshly prepared ice-cold aqueous solution of 25 mM NaBH4, and stir for another 2 min. The color of the solution will turn brown, and then place it in an 80 °C oil bath and react for 15 h. The color turns red to prepare a seed solution, which is stored at room temperature for later use; Add the prepared seed solution to a growth solution containing 10 mL of 10 mM HAuCl4, 2 mL of 10 mM AgNO3, 10 mL of 1.0 M HCl, 1.8 mL of 0.1 M Vc, and 200 mL of 0.1 M CTAC, and slowly stir for 2 min to mix evenly; Finally, place the above mixture in a 30 °C water bath and let it stand for 12 h. Within the first 15 min, the color of the solution gradually changes and finally turns dark green; after the prepared gold nanobipyramids are allowed to stand for 12 h, centrifuge once to disperse the precipitate in water, and then centrifuge again and add 6.67 mL of CTAC for later use.

4. The organic solar cell with a ternary composite material as the hole transport layer according to claim 2, characterized in that, In the above step S2, when adding the gold nanobipyramid dispersion to the PEDOT:PSS solution for reaction, the volume percentage of the gold nanobipyramid dispersion is 0.1% - 5%. The mixed solution is stirred sufficiently to form a uniform and stable ternary system. After filtering through a filter with a pore size of 0.45 μm, spin coat the above solution on the surface of the treated anode substrate at a speed of 3000 - 4500 rpm for 40 - 60 s; perform annealing treatment on the spin-coated anode substrate at a temperature of 120 - 150 °C for 10 - 15 minutes.

5. The organic solar cell with a ternary composite material as the hole transport layer according to claim 1, wherein The thickness of the hole transport layer is 20 - 30 nm.

6. The organic solar cell with a ternary composite material as the hole transport layer according to claim 1, characterized in that The anode substrate is selected from indium tin oxide glass ITO.

7. The organic solar cell using a ternary composite material as a hole transport layer according to claim 1, wherein The material of the organic active layer is PM6:Y6, and the thickness of the active layer is 90 - 120 nm; The material of the electron transport layer is PDINO, and the thickness of the electron transport layer is 50 - 70 nm; The cathode layer is Ag or Cu, and the thickness of the cathode layer is 60 - 80 nm.

8. The preparation method of the organic solar cell using the ternary composite material as the hole transport layer according to any one of claims 1-7, characterized in that, It includes the following steps: S1. Clean the anode substrate and treat the surface of the anode layer of the anode substrate; S2. Spin-coat a hole transport layer on the anode layer processed in step S1; S3. Spin-coat an organic active layer on the hole transport layer processed in step S2; S4. Spin-coat an electron transport layer on the surface of the organic active layer prepared in step S3, and evaporate and deposit a cathode layer.

9. The preparation method of the organic solar cell with the ternary composite material as the hole transport layer according to claim 8, characterized in that, In the above step S1, the cleaning of the anode substrate includes: successively ultrasonically cleaning the ITO glass with dishwashing liquid, deionized water, acetone, and isopropyl alcohol for 25 - 35 minutes each; after drying with nitrogen, performing surface plasma treatment on the surface of the anode substrate with a Plasma cleaner for 1 - 2 minutes.

10. The preparation method of the organic solar cell using the ternary composite material as the hole transport layer according to claim 8, characterized in that, In the above step S3, the material of the organic active layer of the organic solar cell is PM6:Y6, and the mass ratio of PM6 to Y6 is 1:1.

2. It is configured into a solution using the solvent ultradry chloroform, and then the prepared solution is spin-coated on the PEDOT:PSS layer at a speed of 4000 rpm; in the above step S4, the material of the electron transport layer is PDINO, and after the organic active layer, a methanol solution with a concentration of 1.0 mg / mL PDINO is spin-coated and deposited on the organic active layer at a speed of 3000 rpm for 30 seconds to obtain the electron transport layer; the metal cathode Al, Ag or Cu is physically vapor-deposited on the cathode layer in a vacuum of ~10 -4 Pa to obtain the organic solar cell.

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