Characteristics of amorphous silicon solar cells
Characteristics of amorphous silicon (a-Si) solar cells 1) Simple preparation process and low cost; 2) Amorphous silicon (a-Si) has a high optical absorption coefficient, in the visible wavelength range of 0.3150.75 Lm, The optical absorption coefficient is an order of magnitude higher than that of single crystal silicon (c-Si). Therefore, a very thin (about 1Lm) a-Si solar cell can absorb most of the visible light; (1.12eV) is large, so it has a good match with the solar spectrum.
Factors affecting the spectral response of solar cells
1) The doping concentration of the base doping concentration base region is increased, the photon lifetime and the diffusion length of the base region are lowered, and the carrier loss is increased, thereby lowering the low energy spectral response. The base doping concentration has no effect on the high energy spectral response. This is because the absorption coefficient of high-energy photons is large, so the high-energy photons transmitted to the base region are already very weak.
2) Surface recombination velocity The larger the photon energy, the larger the absorption coefficient, and the more concentrated the carriers are on the surface. Therefore, when the surface recombination speed of the solar cell increases, the high energy spectral response becomes small. Since the low-energy photon absorption coefficient is small, the surface recombination velocity has little effect on the low-energy spectrum regardless of the surface recombination velocity.
3) The shallow junction is shallow so that the spectral response of the top region is significantly increased, because the shallowness reduces the loss of surface recombination and top region recombination, thereby increasing the high energy spectral response of the top region.
4) The additional electric field of the additional electric field top region of the top region can increase the spectral response of the high energy photons.
5) The back field back field can improve the low energy spectral response of the base region.