The impact of the bandgap () grading of an earth-abundant multinary chalcogenide CuBaSn(SSe) (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 tuning is performed by compositional variation of Sulfur (S) and Selenium (Se). We investigate the single grading of the absorber by thoroughly optimizing the at the boundaries using linear grading. Double grading of the absorber is performed by employing a parabolic grading profile to vary inside the bulk of the absorber. Major improvements are noticed in performance parameters wherein (a) Open circuit voltage () is improved from 0.67 to 0.91 V, (b) short circuit current density () is improved from 16.4 to 21.28 mA/cm after appropriate grading of the absorber and (c) the PCE of the cell is enhanced from 6.17 to 15.63 %. The effects on the performance parameters with different grading profiles are briefly discussed. The defects with different distribution profiles are studied for graded device. The inherent formation of MoS and MoSe layers are discussed, and the PCE of cell is improved to 16.31% due to formation of ohmic junction. We further propose to modify the Mo back contact with Ni to improve the PCE of the device up to 17.53%. This work presents a systematic approach to optimize of the absorber and boost the advancement in CBTSSe-based photovoltaic devices.

中文翻译：

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用于光伏应用的地球储量丰富的 Cu2BaSn(S1-xSex)4 的带隙工程：双分级的系统方法

使用数值模拟研究了地球丰富的多元硫属化物 CuBaSn(SSe) (CBTSSe) 的带隙 () 分级的影响。电池的基准模型的功率转换效率 (PCE) 为 6.17%，旨在与制造的电池的性能相匹配。调节是通过硫 (S) 和硒 (Se) 的成分变化来进行的。我们通过使用线性分级彻底优化边界来研究吸收器的单一分级。吸收体的双重分级是通过采用抛物线分级轮廓在吸收体内部变化来实现的。性能参数方面取得了重大改进，其中 (a) 开路电压 () 从 0.67 V 提高到 0.91 V，(b) 吸收体适当分级后，短路电流密度 () 从 16.4 mA/cm 提高到 21.28 mA/cm，以及 ( c) 电池的PCE从6.17%提高到15.63%。简要讨论了不同级配配置对性能参数的影响。研究了分级器件的不同分布轮廓的缺陷。讨论了MoS和MoSe层的固有形成，由于欧姆结的形成，电池的PCE提高到16.31%。我们进一步建议用Ni修改Mo背接触，以将器件的PCE提高至17.53%。这项工作提出了一种系统方法来优化吸收器并促进基于 CBTSSe 的光伏器件的进步。