A solution method for preparing crystalline silicon solar cells

Abstract

The invention discloses a process for preparing a crystalline silicon solar cell by a solution method. The method comprises the steps: adding ethyl alcohol, polyethylene glycol, vinyltrimethoxysilaneand the like into a phosphoric acid solution to serve as a phosphorus diffusion solution source, and uniformly coating the surface of a silicon wafer with diffusion liquid through an ultrasonic atomization spraying method; then diffusing phosphorus at the high temperature to obtain the uniform doping concentration of the surface. According to the invention, the solution spraying method is adoptedto prepare a titanium dioxide anti-reflection film to replace a silicon nitride anti-reflection film prepared by a PECVD method, and a microemulsion composed of anionic polyacrylamide (APAM), isopropanol and the like is added into a titanium tetrachloride solution to serve as a precursor solution of the titanium dioxide film, so that the passivation function of the film on the silicon surface is improved.

Description

technical field [0001] The invention belongs to the technical field of solar cells, in particular to a process for preparing crystalline silicon solar cells by a solution method. Background technique [0002] At present, crystalline silicon solar cells have occupied more than 90% of the photovoltaic market. The mainstream crystalline silicon cell preparation processes mainly include: cleaning and texturing, diffusion, removal of phosphosilicate glass, deposition of silicon nitride anti-reflective film, printing electrodes, high temperature sintering Wait. Among them, diffusion is the most critical process, forming a p-n junction through diffusion, generating a built-in electric field, separating photogenerated carriers (electrons and holes), and finally making them collected by two electrodes on the front and rear surfaces of the silicon wafer. At present, the mainstream crystalline silicon cells mainly use p-type crystalline silicon wafers. In the existing industrial produ...

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Problems solved by technology

When phosphorus oxychloride thermally decomposes, without the participation of oxygen, its decomposition is insufficient, and the resulting phosphorus pentachloride is not easy to decompose, and has a corrosive effect on silicon, which will damage the surface state of silicon wafers

In order to increase the stability of the phosphoric acid spin-coating solution, organic solvents such as ethanol, isopropanol or dibutanol are usually added, but from the existing literature, the wettability between the phosphoric acid spin-coating solution and the silicon surface is poor, making spin coating It is difficult for the liquid to be spin-coated evenly on the surface of the silicon wafer, resulting in poor uniformity of phosphorus doping concentration on the silicon surface

In addition, in order to increase the absorption of light by the silicon wafer, the surface of the silicon wafer is usually textured, and the phosphoric acid doped solution is spin-coated on the surface of the silicon wafer after texture, which will make it difficult for the spin-coating solution to reach the bottom of the pyramid on the silicon surface, making The uniformity of phosphorus doping will also become poor

[0004] In order to replace the silicon nitride anti-reflection film deposited by PECVD, there are also reports in the literature that silicon dioxide is formed by using a silicon dioxide spin-coating solution at a high temperature or a silicon dioxide anti-reflection film is formed at a high temperature oxidation, but the silver paste is formed on the silicon dioxide. The fire-through ability in the thin film is very weak, which will deteriorate the contact performance between the silver electrode and silicon, resulting in an increase in contact resistance and affecting the efficiency of the battery