Copper Indium Gallium Selenide ( CIGS ) is a ① semiconductor material.
* ①Compared with indrect-bandgap semiconductors, the direct-bandgap semiconductors emit light more efficiently
because electrons can drop directly from the conduction band to the valence band without changing their momentum, which requires interactions that can drain away energy. In our case, mostly the light energy.
Its structure gives it an ② absorption coefficient of up to 105(cm-1) for visible light at about 1mm, superior to other battery materials. The absorption layer of CIGS thin-film cells only needs to be 1 to 2mm thick to absorb 90 percent of the sunlight.ading text.
* ②The absorption coefficient determines how deeply a specific wavelength of light can penetrate a material before being absorbed. For instance, light is poorly absorbed by a material with a low absorption coefficient.
At the same time, CIGS are constructed with ③ High defect tolerance, making them still maintain a high performance level even when there are defects or impurities in the material,
achiving a higher efficiency.
* ③Defect tolerance indicates either a low density of defects in the material or a relative insensitivity of functional properties to defects.