On the Optical Properties of the Cu2ZnSn[S1−xSex]4 System in the IR Range

Following the recent classification by European Commission of some elements as critical raw materials (CRM), there is an increasing interest in development CRM-free thin film photovoltaic (PV) technologies, including kesterite materials. Moreover, starting with performance breakthrough reported IBM 2010, efficiency kesterite-based solar cells steadily progressed following years achieving. Therefore, years, has been a significant research effort to develop devices. However, despite large number theoretical and experimental works, many aspects problem have not yet fully studied. issues considered article, especially behavior absorption photoconductivity spectra Cu2ZnSn[S1−xSex]4 system, depending on S/Se ratio, are extremely important and, at same time, one topical poorly studied problems. In this work, using quantum-chemical calculations framework density functional theory (DFT), we study optical properties semiconductor nanocrystals Cu2ZnSnS4 doped Se. Using WIEN2k package, concentration dependences characteristics system (x = 0.00, 0.25, 0.50, 0.75 1.00) were calculated. It shown that doping Se S position leads noticeable improvement photoabsorbing these nanocrystals, well their IR range. The calculated extinction spectra, refractive indices permittivity under study, compared data known from literature. obtained will significantly enrich existing knowledge about contribute expansion field application compounds optoelectronic HIGHLIGHTS With increase concentration, absorbing band gap narrows Se/S ratio Curves k(ω) α (ω) correspond maxima e2 (w) Pure Cu2ZnSnSe4 maximum range GRAPHICAL ABSTRACT