查看文章

The impact of the bandgap (Eg) grading of an earth-abundant multinary chalcogenide Cu₂BaSn(S_1-xSe_x)₄ (CBTSSe) is investigated using numerical simulation. The baseline model of the cell with a power conversion efficiency (PCE) of 6.17 % is designed to match the performance of the fabricated cell. The Eg tuning is performed by compositional variation of Sulfur (S) and Selenium (Se). We investigate the single grading of the absorber by thoroughly optimizing the Eg at the boundaries using linear grading. Double grading of the absorber is performed by employing a parabolic grading profile to vary Eg inside the bulk of the absorber. Major improvements are noticed in performance parameters wherein (a) Open circuit voltage (Voc) is improved from 0.67 to 0.91 V, (b) short circuit current density (Jsc) is improved from 16.4 to 21.28 mA/cm² after appropriate grading of the absorber and (c) the PCE of the cell is …