Series resistance imaging of silicon solar cells by lock-in photoluminescence

An advanced method for determining the spatially resolved series resistance of silicon solar cells by lock-in photoluminescence (LIPL) is presented, which only needs two LIPL images taken at different illumination levels similarly to the photoluminescence (PL) method. However, the LIPL approach does not require the calibration images at short circuit conditions, and it has the merit of improving the signal to noise ratio (SNR) in comparison with the PL method. Furthermore, the R_s images obtained by LIPL are in good agreement with PL, and the LIPL method seems more independent of the acquisition time which could make the acquisition time short. Thus, LIPL could provide a possible approach to achieve more accurate inline characterization of spatially resolved information.