A technique for inducing film formation of a pedot:pss solution on a silicon pyramid suede structure

Abstract

The application discloses a kind of induced PEDOT:PSS solution on the silicon pyramid nap structure film forming technology, specifically includes the following steps: (1) using alkaline solution method is prepared pyramid structure on silicon surface, silicon wafer is cut into 1 × 1 cm 2 ; (2) glycol, surfactant TX-100 are added in PEDOT:PSS solution, then using magnetic stirring is mixed uniformly;(3) appropriate ethanol is dropped on the silicon surface with pyramid structure;(4) after step (3) is completed, immediately take 80 microliters PEDOT:PSS solution obtained in step (2) is dropped on the surface of ethanol film;(5) after standing 60 seconds, select a certain speed and spin 40 seconds;(6) the silicon wafer obtained in step (5) is placed in oven with temperature of 120 DEG C and is dried.The application provides a kind of simple, efficient PEDOT:PSS solution film forming technology, can effectively improve the heterojunction area of PEDOT:PSS / silicon hybrid solar cell, improve the photoelectric performance of solar cell.Meanwhile, the technology is also applicable to other water solution on the silicon surface film forming.

Description

Technical Field

[0001] The invention relates to the field of organic optoelectronic technology materials, and in particular provides a technology for inducing the formation of a conformal film of a PEDOT:PSS solution on a silicon pyramid velvet structure. Background Art

[0002] PEDOT:PSS has attracted considerable attention in recent years as a hole-selective contact material for silicon-based hybrid solar cells due to its low cost and simple film-forming methods. To effectively utilize light in solar cells, silicon surfaces are often designed with light-trapping structures, such as nanopillar arrays, nanowire arrays, porous silicon, and pyramid arrays. The pyramid structures' controlled low density and size, combined with their excellent light-trapping capabilities, significantly reduce light reflection, make them a leader among these structures. PEDOT:PSS layers can be deposited directly onto these light-trapping structures via spin coating.

[0003] However, in the traditional film-forming process, the water-soluble PEDOT:PSS solution covers the undulating pyramid surface, and the surface tension of water prevents PEDOT:PSS from reaching the bottom of the pyramid structure. At the same time, the contact angle between the PEDOT:PSS solution and the pyramid structure is another major factor affecting the liquid wettability. Therefore, direct spin coating on the pyramid structure will damage the effect of the conformal film.

[0004] Currently, most conformal coating methods include ultrasonic atomization, DEP secondary spin coating, and the addition of surfactants. To ensure light absorption, the light-trapping structure on the silicon surface is optimized. These methods are technically complex and costly. Furthermore, they can also result in low film quality and secondary contamination of the silicon substrate.

[0005] The technique of using ethanol to induce the PEDOT:PSS solution to form a film on the silicon pyramid texture allows the PEDOT:PSS solution to easily reach the base of the pyramid, achieving a high-quality film. This technique also offers the advantages of high controllability and suitability for multi-scale pyramid structures. Furthermore, the preparation process is simple, pollution-free, and low-cost. Summary of the Invention

[0006] The present invention aims to provide a simple, low-cost process for forming a high-quality, conformal film of a PEDOT:PSS solution on a silicon pyramid velvet structure. The ethanol-induced PEDOT:PSS solution technology provided by the present invention achieves good contact between the PEDOT:PSS solution and the base of the pyramids on the silicon velvet structure. This reduces the contact angle between the solution and the pyramid structure and increases the contact area between the organic film and the silicon substrate, thereby improving conformality and boosting photoelectric conversion efficiency.

[0007] The present invention provides a method for inducing a PEDOT:PSS solution to form a conformal film on a silicon pyramid velvet structure as follows:

[0008] (1) A pyramid structure was etched on the polished silicon surface of a 4-inch circular silicon wafer using potassium hydroxide (KOH) solution at 85°C for 30 minutes. After etching, the wafer was thoroughly rinsed with deionized water and cut into squares of equal size for later use.

[0009] (2) Add 2000 μL of PEDOT:PSS solution, 5 wt% ethylene glycol (EG), and 0.25 wt% surfactant (TX-100) to a brown vial, place a magnetic particle in the solution, and stir at 400 rpm to mix thoroughly. Set aside.

[0010] (3) taking 10-20 μl of an ethanol solution with a concentration greater than 99%, dropping it on the silicon surface of the pyramid structure prepared in step (1), and spin coating at 300 rpm for 5 seconds to obtain a uniform ethanol film on the silicon pyramid surface;

[0011] (4) After step (3), while the ethanol has not yet evaporated, 80 μL of the PEDOT:PSS solution obtained in step (2) is dropped onto the surface of the ethanol film;

[0012] (5) After step (4) is completed, the solution is allowed to stand for 60-70 seconds, and a spin coating method is used to deposit the solution on the silicon surface into a film at a rotation speed of 1000-7000 rpm, with a spin coating time of 40 seconds;

[0013] (6) The silicon wafer obtained in step (5) was placed in an oven at a temperature of 120° C. for drying for 15 minutes.

[0014] Furthermore, the concentration of the potassium hydroxide solution in step (1) is 1.1% to 2%.

[0015] In another step, the potassium hydroxide solution in step (1) contains 8% to 10% isopropyl alcohol.

[0016] Furthermore, in step (4), 80 μl of the PEDOT:PSS solution obtained in step (2) is dropped onto the surface of the ethanol film in the shortest possible time to ensure that the ethanol on the silicon surface does not evaporate excessively in this step, thereby ensuring the effectiveness of ethanol induction.

[0017] Furthermore, in step (5), ethanol and PEDOT:PSS solution are fully dissolved, and the good wettability between ethanol and silicon and the good miscibility between ethanol and aqueous solution are utilized to induce the PEDOT:PSS solution with poor wettability on the silicon surface to achieve good contact between the PEDOT:PSS solution and the silicon surface.

[0018] Using this technical solution, the inventors used ethanol, which has excellent wettability with silicon wafer surfaces, as an induction layer to guide the PEDOT:PSS aqueous solution, which has poor wettability with the silicon surface, to the base of the pyramidal structure on the silicon surface. The ethanol and aqueous solution have good miscibility, ensuring better contact. After this, a film was deposited using a spin coating method. By controlling the spin coating speed and time of the ethanol, the PEDOT:PSS solution was induced to form a film on the silicon surface, effectively improving the heterojunction contact quality of silicon-based hybrid solar cells and contributing to improved performance.

[0019] The present invention provides a technique for conformally depositing PEDOT:PSS thin films on silicon pyramid velvet structures, requiring no expensive equipment, generating no pollution, and being simple and low-cost. The PEDOT:PSS solution is brought into contact with the silicon pyramid surface by ethanol induction, followed by spin coating to form the PEDOT:PSS thin film. This preparation method is applicable to silicon surface pyramid structures of various scales, achieving good heterojunction contact, promoting carrier separation, and improving the performance of silicon-based hybrid solar cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a SEM image of a PEDOT:PSS film prepared according to the first embodiment of the present invention without using ethanol induction;

[0021] Figure 2 is a SEM image of an ethanol-induced PEDOT:PSS film prepared according to the second embodiment of the present invention;

[0022] Figure 3 is a SEM image of an ethanol-induced PEDOT:PSS film prepared according to the fourth embodiment of the present invention;

[0023] Figure 4 Schematic diagram of ethanol-induced PEDOT:PSS film formation according to the present invention. DETAILED DESCRIPTION

[0024] The present invention will be described in detail below with reference to the accompanying drawings:

[0025] Example 1 (control example): No ethanol was used to induce the deposition of a PEDOT:PSS solution into a film on the surface of a silicon pyramid.

[0026] (1) A potassium hydroxide (KOH) solution containing 920 ml of high-purity deionized water, 80 ml of isopropyl alcohol, and 20.466 g of potassium hydroxide (KOH) was used to etch a pyramid structure on the polished silicon surface of a 4-inch circular silicon wafer at 85°C for 30 minutes. After etching, the silicon wafer was thoroughly rinsed with deionized water and cut into 1×1 cm 2 ,spare;

[0027] (2) Add 2000 μL of PEDOT:PSS solution, 5 wt% ethylene glycol, and 0.25 wt% surfactant (TX-100) to a brown vial, place a clean magnet in the solution, and stir at 400 rpm to mix thoroughly. Set aside.

[0028] (3) Take 80 μL of the PEDOT:PSS solution obtained in step (2) and drop it on the surface of the ethanol film;

[0029] (4) After step (3) is completed, the solution is allowed to stand for 60 seconds, and then the solution is spin-coated on the silicon surface at 3000 rpm to form a film, and the spin coating time is 40 seconds;

[0030] (5) The silicon wafer obtained in step (4) was placed in an oven at a temperature of 120° C. for drying for 15 minutes.

[0031] Example 2

[0032] (1) A potassium hydroxide (KOH) solution containing 920 ml of high-purity deionized water, 80 ml of isopropyl alcohol, and 11.154 g of potassium hydroxide (KOH) was used to etch a pyramid structure on the polished silicon surface of a 4-inch circular silicon wafer at 85°C for 30 minutes. After etching, the silicon wafer was thoroughly rinsed with deionized water and cut into 1×1 cm 2 ,spare;

[0033] (2) Add 2000 μL of PEDOT:PSS solution, 5 wt% ethylene glycol, and 0.25 wt% surfactant (TX-100) to a brown vial, place a magnetic particle in the solution, and stir at 400 rpm to mix thoroughly. Set aside.

[0034] (3) taking 15 μl of an ethanol solution with a concentration greater than 99%, dropping it onto the silicon surface of the pyramid structure prepared in step (1), and spin coating at 300 rpm for 5 seconds to obtain a uniform ethanol film on the silicon pyramid surface;

[0035] (4) After step (3), while the ethanol has not yet evaporated, 80 μL of the PEDOT:PSS solution obtained in step (2) is dropped onto the surface of the ethanol film;

[0036] (5) After step (4) is completed, the solution is allowed to stand for 60 seconds, and then the solution is spin-coated on the silicon surface at 3000 rpm to form a film, and the spin coating time is 40 seconds;

[0037] (6) The silicon wafer obtained in step (5) was placed in an oven at a temperature of 120° C. for drying for 15 minutes.

[0038] Example 3

[0039] (1) A potassium hydroxide (KOH) solution containing 920 ml of high-purity deionized water, 80 ml of isopropyl alcohol, and 20.466 g of potassium hydroxide (KOH) was used to etch a pyramid structure on the polished silicon surface of a 4-inch circular silicon wafer at 85°C for 30 minutes. After etching, the silicon wafer was thoroughly rinsed with deionized water and cut into 1×1 cm 2 ,spare;

[0040] (2) Add 2000 μL of PEDOT:PSS solution, 5 wt% ethylene glycol, and 0.25 wt% surfactant (TX-100) to a brown vial, place a clean magnet in the solution, and stir at 400 rpm to mix thoroughly. Set aside.

[0041] (3) taking 15 μl of an ethanol solution with a concentration greater than 99%, dropping it onto the silicon surface of the pyramid structure prepared in step (1), and spin coating at 300 rpm for 5 seconds to obtain a uniform ethanol film on the silicon pyramid surface;

[0042] (4) After step (3), while the ethanol has not yet evaporated, 80 μL of the PEDOT:PSS solution obtained in step (2) is dropped onto the surface of the ethanol film;

[0043] (5) After step (4) is completed, the solution is allowed to stand for 60 seconds, and then the solution is spin-coated on the silicon surface at 7000 rpm to form a film, and the spin coating time is 40 seconds;

[0044] (6) The silicon wafer obtained in step (5) was placed in an oven at a temperature of 120° C. for drying for 15 minutes.

[0045] Example 4

[0046] (1) A potassium hydroxide (KOH) solution containing 920 ml of high-purity deionized water, 80 ml of isopropyl alcohol, and 11.154 g of potassium hydroxide (KOH) was used to etch a pyramid structure on the polished silicon surface of a 4-inch circular silicon wafer at 85°C for 30 minutes. After etching, the silicon wafer was thoroughly rinsed with deionized water and cut into 1×1 cm 2 ,spare;

[0047] (2) Add 2000 μL of PEDOT:PSS solution, 5 wt% ethylene glycol, and 0.25 wt% surfactant (TX-100) to a brown vial, place a clean magnet in the solution, and stir at 400 rpm to mix thoroughly. Set aside.

[0048] (3) taking 15 μl of an ethanol solution with a concentration greater than 99%, dropping it onto the silicon surface of the pyramid structure prepared in step (1), and spin coating at 300 rpm for 5 seconds to obtain a uniform ethanol film on the silicon pyramid surface;

[0049] (4) After step (3), while the ethanol has not yet evaporated, 80 μL of the PEDOT:PSS solution obtained in step (2) is dropped onto the surface of the ethanol film;

[0050] (5) After step (4) is completed, the solution is spin-coated on the silicon surface to form a film at 3000 rpm for 40 seconds;

[0051] (6) The silicon wafer obtained in step (5) was placed in an oven at a temperature of 120° C. for drying for 15 minutes.

[0052] The present invention is not limited to the above-described embodiments, and many variations in details are possible without thereby affecting the scope and spirit of the present invention.

[0053] Matters not covered by the present invention are known technologies.

[0054] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made in accordance with the spirit of the present invention are intended to be covered by the scope of protection of the present invention.

Claims

1. A technology for inducing PEDOT:PSS solution to form a conformal film on a silicon pyramid texture structure, characterized in that: The following steps are involved: (1) Using potassium hydroxide (KOH) solution to prepare pyramid structures on the silicon surface, the silicon wafer was cut into squares of equal size; (2) Add PEDOT:PSS solution, 5 wt% ethylene glycol (EG), and 0.25 wt% surfactant (TX-100) to a brown vial in sequence, place a magnet in the solution, and stir at 400-800 rpm to mix thoroughly. Set aside. (3) taking 10-20 μl of an ethanol solution with a concentration greater than 99%, dropping it onto the silicon surface of the pyramid structure prepared in step (1), and spin coating at 300-400 rpm for 5-8 seconds; (4) After step (3), while the ethanol has not yet evaporated, immediately take 80-100 μl of the PEDOT:PSS solution obtained in step (2) and drop it on the surface of the ethanol film; (5) After step (4) is completed, the solution is allowed to stand for 60-70 seconds, and a spin coating method is used to deposit the solution on the silicon surface into a film at a rotation speed of 1000-7000 rpm, with the spin coating time being 40-60 seconds; (6) The silicon wafer obtained in step (5) is placed in an oven at a temperature of 120° C. for drying for 15-20 minutes.

2. A method for inducing the formation of a conformal film of a PEDOT:PSS solution on a silicon pyramid texture structure according to claim 1, characterized in that: The specific coating order of the ethanol solution and PEDOT:PSS solution described in steps (3), (4) and (5) is as follows: drop an appropriate amount of ethanol on the surface of the silicon pyramid, spin-coat at 500-600 rpm for 5-8 seconds, then drop the PEDOT:PSS solution obtained in step (2) on the surface of the pyramid, let it stand for 60-70 seconds, and then spin-coat at 1000-7000 rpm for 40-60 seconds.

3. The method of inducing the conformal deposition of a PEDOT:PSS solution on a silicon pyramid texture structure according to claim 1, characterized in that: In the ethanol coating method in step (3), after ethanol is dripped onto the surface of the silicon pyramid, the spin coating is immediately performed at 300-500 rpm for 5-8 seconds.

4. The method of inducing the conformal deposition of a PEDOT:PSS solution on a silicon pyramid texture structure according to claim 1, characterized in that: When the PEDOT:PSS solution is dropped in step (4), before the ethanol evaporates, 80-100 μl of the PEDOT:PSS solution obtained in step (2) is immediately dropped on the surface of the ethanol film.

5. The method of inducing the conformal deposition of a PEDOT:PSS solution on a silicon pyramid texture structure according to claim 1, characterized in that: The PEDOT:PSS solution described in step (5) is dropped onto the surface of the silicon pyramid and then allowed to stand for 60-70 seconds.

6. The method of inducing the conformal deposition of a PEDOT:PSS solution on a silicon pyramid texture structure according to claim 1, characterized in that: The specific parameters for spin coating the PEDOT:PSS solution in step (5) are: a rotation speed in the range of 1000-7000 rpm, and a spin coating time of 40-60 seconds.

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