Device Simulation of Ag2SrSnS4 and Ag2SrSnSe4 Based Thin-Film Solar Cells from Scratch

The structural, optoelectronic and elastic properties of quaternary chalcogenide materials Ag2SrSn(S/Se)(4) in kesterite (Kes) and stannite (Sta) phases are studied using the HSE hybrid functional within the density functional theory. Ag2SrSnSe4 in kesterite and stannite phases is found to have direct bandgap of 1.13 and 1.38 eV, respectively, along the high symmetry I' points. To analyze the electronic properties, PDOS for Ag2SrSn(S/Se)(4) in kesterite and stannite phases are studied and explained. To get more insights into the optical behavior of the materials the authors also investigate the dielectric function, refractive function, absorption spectrum, extinction coefficient, reflectivity, and optical conductivity. They also calculate the single-layer absorber efficiency of Ag2SrSn(S/Se)(4) in kesterite and stannite phases using the spectroscopic limited maximum efficiency (SLME) approach to predict their potential as an efficient absorber layer material in thin-film solar cells (TFSC). The SLME for Ag2SrSnSe4 in kesterite and stannite phases is found to be 31.4% and 32.4%, respectively. Further, a complete solar cell device analysis with these materials as an absorber layer is carried out using the SCAPS-1D software. They found that devices with the kesterite and stannite structure of Ag2SrSnSe4 have a predicted efficiency of 20.04% and 18.59%, respectively.