Solar cell and preparation method thereof

[0025] The present invention also provides a method for preparing the solar cell, comprising the following steps:

[0026] A. Deposit SiO on the back of N-type single crystal silicon substrate 2 passivation layer;

[0027] B. In SiO 2 A metal aluminum layer is printed on the passivation layer, and then the metal aluminum layer is point-contacted with the N-type single crystal silicon substrate by laser sintering to form a P-N junction;

[0028] C. On the front side of the N-type single crystal silicon substrate, the intrinsic amorphous silicon layer and N + type amorphous silicon layer;

[0029] D. in N + A transparent conductive layer is formed on the surface of the type amorphous silicon layer by sputtering, and then silver electrodes are printed on the surface of the transparent conductive layer.

[0030] Preferably, SiO is deposited on the back of the N-type single crystal silicon substrate 2 Before the passivation layer, it needs to be cleaned by RCA. The purpose of t

[0042] Example 1

[0043] (1) Use an N-type single crystal silicon wafer with a thickness of 220 μm, a resistivity of 10 Ω cm, and a minority carrier lifetime of 1 ms as the substrate, and use NaOH solution to perform anisotropic etching on the front side of the substrate to make the surface concave-convex, and then carry out RCA wash, rinse and spin dry.

[0044] (2) Substrate backside passivation: place the N-shaped single crystal silicon substrate in a quartz tube, pass in water vapor and oxygen, and heat to 900°C to form SiO with a thickness of 120nm on the surface of the N-shaped single crystal silicon substrate 2 film.

[0045] (3) LFC: SiO on the back of N-type substrate by screen printing process 2 Print a metal Al layer on the film to form a metal aluminum layer with a thickness of 15 μm; then laser sinter the metal aluminum layer to make point contact between the metal aluminum layer and the N-type substrate silicon wafer to form 100 P-N junctions; the conditions for

[0048] Example 2

[0049] The same steps as in Example 1 were used to prepare the solar cell S2 of this example, the difference being that:

[0050] In step (2), the N-shaped single crystal silicon substrate is placed in a quartz tube, water vapor and oxygen are introduced, and heated to 900°C to form SiO with a thickness of 150nm on the surface of the N-shaped single crystal silicon substrate. 2 film.