Insight into the mechanism of Sb promoted Cu(In,Ga)Se2 formation

Sb-doping has been demonstrated to be a new approach to promote Cu(In,Ga)Se 2 (CIGS) thin film formation . To study the mechanism of Sb-promoted CIGS formation, we investigated the influence of Sb on the evolution of the critical intermediate Cu–Se phases, and found that Cu 3 SbSe 3 species was formed. Phase change of the as-prepared Cu–Se compounds at elevated temperature was determined using the differential scanning calorimetry analysis. For samples containing Sb, the melting decomposition occurred at 507.1   °C, along with aggregation of nanocrystals into a bulk, while the morphology of the sample without Sb barely changed after heating. This result suggests that the mobile Cu 3 SbSe 3 is likely the key intermediate responsible for Sb-promoted CIGS formation. Furthermore, we extended the scope of Sb-doping approach to solvothermal synthesis and CIGS nanocrystals were synthesized with significantly promoted kinetics in the presence of Sb. Based on these results, we propose the mechanism of Sb promoted CIGS formation.