Crystalline silicon solar cell and preparation method thereof

Abstract

The invention discloses a crystalline silicon solar cell and a preparation method thereof, and the crystalline silicon solar cell comprises a pn plus junction silicon substrate, wherein a first amorphous alumina layer and an amorphous silicon nitride layer are arranged on the surface of an n plus emitter, a silver electrode penetrates the amorphous silicon nitride layer and the first amorphous alumina layer and is connected with the n plus emitter, a composite passivation medium layer is arranged on the surface of a p type substrate, the p type substrate comprises a silicon oxide layer and a second amorphous alumina layer, and a p type substrate is in contact with a back electrode. The preparation method comprises the special preparation of the composite passivation medium layer, nitric acid and hydrogen peroxide solution are adopted for processing the surface of the p type substrate, the sol-gel process is adopted for preparing the second amorphous alumina layer, and the composite passivation medium layer (4) is formed after annealing. The crystalline silicon solar cell has the advantages of simple process, low equipment investment, good passivation and anti-reflection performances of the front surface, excellent passivation effect of the composite passivation medium layer on the back surface, capability of improving the utilization efficiency of long waves, and the like.

Description

technical field [0001] The invention relates to a crystalline silicon solar cell and a preparation method thereof, in particular to a crystalline silicon solar cell with a double-layer front surface passivation anti-reflection medium layer and a back surface composite passivation medium layer and a preparation method thereof. Background technique [0002] At present, most commercial crystalline silicon solar cells use screen printing technology, which has a simple process flow, avoids the application of a large number of vacuum equipment, and is convenient for mass production. Such as figure 2 As shown, the basic process is as follows: 1. Removing silicon surface damage, forming anti-reflection structure and chemical cleaning by acid or alkali texturing; 2. In POCl 3 Diffusion and removal of peripheral pn+ junctions and phospho-silicate glass in the atmosphere; 3. Deposit SiNx:H anti-reflection film by PECVD; 4. Screen printing front, back electrodes and back surface fields...

AI Technical Summary

Problems solved by technology

However, SiO 2 The passivation layer is generally prepared by high-temperature thermal oxidation at 900-1100°C, which has a serious impact on the composite of low-quality solar-grade silicon wafers, and requires the application of expensive photolithography technology. The complex process is not conducive to large-scale industrial production

The amorphous silicon nitride layer is used as the passivation layer on the front surface, and it is also an anti-reflection layer. Due to the process, the passivation and anti-reflection effects cannot achieve the optimal effect at the same time.

In theory, double-layer silicon nitride films can effectively improve passivation and anti-reflection effects when the refractive index and thickness match, but due to the difficulty in preparing amorphous silicon nitride with a refractive index less than 1.9, it is difficult to achieve in practical applications. Anti-reflection effect of double-layer film

Gradient index silicon nitride films are also difficult to realize due to process problems

Amorphous silicon / amorphous silicon nitride double-layer film can play a good passivation effect, but it is not compatible with the high temperature of 800 ℃ used in subsequent screen printing, because amorphous silicon is easy to crystallize at high temperature, crystallization It is difficult to achieve the ideal passivation effect after

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