Silicon solar cell front face electrode silver paste and preparing method thereof

Abstract

The invention discloses silicon solar cell front face electrode silver paste. The silicon solar cell front face electrode silver paste comprises, by mass, 75-80 percent of silver powder, 3-10 percent of lead-free glass powder, 10-15 percent of organic vehicle and 0.5-3 percent of additive. The silver powder is the spherical micro silver powder with nano bismuth serving as the core, the silver content is 99.1-99.7 percent, the bismuth content is 0.3-0.9 percent, the particle size is 1-2 microns, the tap density is 4.5-5.0 g / ml, the specific surface area is 0.4-1.0 m<2> / g, and the silver powder is prepared by conducting liquid-phase chemical reduction on bismuth nitrate and silver nitrate through glyoxal or acetaldehyde. Bismuth-silicon-antimony-molybdenum lead-free glass powder serves as an adhesive, and potassium fluotitanate, potassium fluoroaluminate, magnesium fluoride and the like are added to serve as the silicon nitride antireflective film eroding additive. According to the silicon solar cell front face electrode silver paste, the contact resistance between a silver electrode and a silicon wafer can be reduced, the stripping strength of the electrode is improved, the electrical property of a solar cell is improved, the production cost of the conductive silver paste is reduced, and the requirement for nonexistence of lead and environmental friendliness are met.

Description

technical field [0001] The invention relates to a silver paste for a front electrode of a silicon solar cell and a preparation method thereof, which is suitable for a silicon solar cell system requiring high photoelectric conversion efficiency and high printing precision, and belongs to the field of new materials and solar cells. Background technique [0002] A solar cell is a semiconductor device that can convert solar energy into electrical energy. Under the condition of light, the solar cell will generate current, collect and transmit electricity through grid lines and electrodes. The industrial production of crystalline silicon cells consists of slicing p-type crystalline silicon materials, cleaning and chemical etching to make texture; phosphorus diffusion on the light-receiving surface to form a p-n junction; coating silicon nitride anti-reflection layer; printing aluminum paste on the surface by screen printing On the back of the silicon wafer, the silver paste is pri...

AI Technical Summary

Problems solved by technology

[0008] In order to make the lead-free glass powder binder and silver powder mix more evenly, the particle size of the glass powder binder is generally controlled below 10μm, and the dosage is controlled at 0.5%-10% of the total weight of the conductive silver paste. If the dosage is less than 0. If the amount exceeds 10%, it will affect the etching of the anti-reflection film and the adhesion between the silicon substrate and the silver electrode; if the amount exceeds 10%, it will reduce the conductivity of the silver electrode

The existing lead-free conductive silver paste has a narrow sintering temperature range, large volume resistance, average adhesion of the silver layer on the silicon wafer, electrode solderability and oxidation resistance. relatively high