DFT study of the electronic, optical and elastic properties of Cu2-xAgxMgSnS4 (x=0, 0.5, 1, 1.5, 2) alloys using TB-mBJ+U potential

In this study, we have conducted first-principles computations on the promising photovoltaic materials Cu2-xAgxMgSnS4 (x = 0, 0.5, 1, 1.5, 2). To determine the electronic characteristics of Cu2-xAgxMgSnS4(x = 0, 0.5, 1, 1.5, 2) in kesterite and stannite phases, we have used the Wien2k code based on density functional theory with the generalised gradient approximation (GGA) and modified Becke-Johnson (TB-mBJ) exchange potential. The results obtained by TB-mBJ likewise fall short of the experimental findings, like GGA and LDA. To get a comparable bandgap value with the experimental results, we have employed the TB-mBJ potential coupled with the Hubbard U correction (TB-mBJ + U), resulting in a more accurate representation of the pd hybridization. Electronic structure calculation reveals Cu2-xAgxMgSnS4(x = 0, 0.5, 1, 1.5, 2) materials as direct bandgap semiconductors, with band gaps ranging from 1.477 eV to 2.38 eV. The computed elastic constants confirm the mechanical stability of all materials. Additionally, we explored optical properties essential for their potential as absorber layers in photovoltaic applications, such as the imaginary and real components of the dielectric function, absorption coefficient, refractive index, reflectivity, and extinction coefficient. These predicted parameters provide valuable insights for researchers, facilitating further investigations into the photovoltaic potential of Cu2-xAgxMgSnS4 materials<bold>.</bold>