Abstract In this work, generalized gradient approximation (GGA) and the Heyd-Scuseria-Ernzerhof (HSE) hybrid functional within the framework of density functional theory (DFT) are used to investigate the structural, electronic and optical properties of Ag2MgSn(S/Se)4 quaternary chalcogenides in kesterite and stannite phases. The kesterite and stannite phases of Ag2MgSn(S/Se)4 are optimized and the values of lattice constants are calculated. The predicted energy bandgaps are found to be direct in nature along the Γ direction, with highest bandgap energy of less than 1.64 eV for Ag2MgSnS4 in kesterite phase. The total and partial density of states are analysed in detail. The optical properties such as imaginary and real parts of dielectric function, refractive index, reflectivity and extinction coefficient are also discussed. Further, in order to understand the light trapping capacity, we examine the absorption coefficients of Ag2MgSnS4 and Ag2MgSnSe4 materials and explore their applicability as solar cell absorber layers. The predicted values of all parameters will help researchers to carry out further investigations on these materials for photovoltaic applications.

中文翻译：

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Ag2MgSn(S/Se)4 四元硫属化物作为太阳能电池吸收层的结构、电子和光学性质：从头算研究

摘要 在这项工作中，广义梯度近似 (GGA) 和密度泛函理论 (DFT) 框架内的 Heyd-Scuseria-Ernzerhof (HSE) 混合泛函被用来研究 Ag2MgSn(S/Se) 的结构、电子和光学性质。 )4 黄铜矿和锡石相中的四元硫属化物。优化了 Ag2MgSn(S/Se)4 的锌黄锡矿和锡石相，并计算了晶格常数值。发现预测的能带隙本质上沿 Γ 方向是直接的，对于黄铜矿相中的 Ag2MgSnS4，最高带隙能量小于 1.64 eV。详细分析了状态的总密度和部分密度。还讨论了介电函数的虚部和实部、折射率、反射率和消光系数等光学特性。更多，为了了解光捕获能力，我们检查了 Ag2MgSnS4 和 Ag2MgSnSe4 材料的吸收系数，并探讨了它们作为太阳能电池吸收层的适用性。所有参数的预测值将有助于研究人员对这些用于光伏应用的材料进行进一步研究。