Fast quantum efficiency measurement of solar cells by Fourier transform photocurrent spectroscopy

Fourier Transform Photocurrent Spectroscopy (FTPS) was introduced four years ago as a method providing fast and highly sensitive evaluation of the spectral dependence of the photoconductive thin film optical absorption coefficient. Recently the method was also applied to the quality assessment of thin film silicon solar cells. In this contribution, we present the FTPS characterization of various thin film solar cells to provide a rapid quantum efficiency (QE) measurement. Furthermore, we study the possibility of the FTPS–QE measurement of a single cell incorporated in the solar module when only the module terminals can be used for connection. FTPS results are compared to lengthy standard QE measurements. The homogeneity study was done for a-Si:H single junction solar module (30 × 30 cm) consisting of 27 series-connected subcells. The QE–FTPS measurement is proved to be very fast, enabling a quick verification of the light intensity dependence or the influence of the forward and reverse bias on QE results over the whole measured spectral range (400–1200 nm).