The application of electroluminescence imaging to detection the hidden defects in silicon solar cells

A method of using electroluminescence(EL) imaging to detect the hidden defects in silicon solar cells under the condition of certain bias is presented in this paper.The EL wavelength of silicon solar cells ranges from 850 nm to 1 200 nm.In the case of forward bias,the EL intensity is related to the concentration and diffusion length of minority carriers,but under the reverse bias,EL regime and illumination intensity are corresponding to defect areas and defect density of battery,respectively.The EL of solar cells can be quickly captured by silicon CCD camera,and the hidden defects of silicon solar cell can be found according to the intensity value of EL imaging.Since the EL intensity of the intrinsic deficient is more sensitive to temperature than that of the extrinsic defect,the types of defect can be checked out by the difference of EL intensity,which responds to the change of temperature.