Composite microsphere with core-shell structure and preparation method thereof

Abstract

The invention provides a composite microsphere with a core-shell structure and a preparation method thereof. The composite microsphere comprises nanoscale silver particles, a SiO2 shell and a cross-linked polymer, wherein the nanoscale silver particles are intensively distributed at the position, close to the center, of the composite microsphere, and the SiO2 shell wraps the outer surfaces of thenanoscale silver particles; the outer surface of the SiO2 shell is coated with the cross-linked polymer; the particle size of the nanoscale silver particles ranges from 1 nanometer to 200 nanometers,and the thickness of the SiO2 shell is between 1 nanometer and 30 nanometers. According to the composite microsphere provided by the invention, in the sintering process, more silver particles with nano-scale particle sizes can enter the molten glass layer, so that the silver content in the glass layer is increased, the silver-silicon contact points are increased, and the conductivity of the sintered silver wire is effectively improved.

Description

technical field [0001] The invention relates to the technical field of solar cells, in particular to a composite microsphere with a core-shell structure and a preparation method thereof. Background technique [0002] The metal wires of the electrodes of crystalline silicon solar cells are usually silver wires, which are formed by sintering conductive silver paste. layer on the silicon wafer, and then sintered to form the conductive silver wire. The conductivity of conductive silver wire is an important technical indicator that determines the performance of solar cells, and the conductivity of conductive silver wire has a great correlation with the composition, rheology, printing process, and sintering process of conductive silver paste. Generally, the existing silicon wafer used for solar cells on the market has a thickness of about 180 microns. In order to save costs, the thickness of the silicon wafer can also be reduced to 150 microns; the thickness of the positive elect...

AI Technical Summary

Problems solved by technology

The particle size of the silver particles contained in the conductive silver paste in the prior art is micron, because the particle size of the silver particles in the micron is relatively large and the surface excess free energy is low, thus resulting in the melting of the glass layer. The amount of silver dissolved or deposited is limited, which in turn leads to insufficient silver-silicon structure points, so the conductivity of the sintered silver wire is poor, thereby reducing the performance of the solar cell

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