Understanding photoluminescence of bismuth-doped ternary alkaline earthd10metal oxides via first-principles calculations br

Bismuth-activated light emissions have been much reported in ternary alkaline earthd10metal oxides, andthe self-activation nature of these hosts makes it possible to achieve efficient luminescence via energy transferbetween the host and the activator ions. A detailed analysis of the potential intrinsic defects accounting forthe intrinsic emissions is still absent, and the identifications of bismuth-related transitions remain unclear orcontroversial. Given these facts, first-principles calculations using hybrid functionals are employed to systemati-cally study the bismuth-doped (Sr/Ca)Sb2O6,(Sr/Ca)2Sb2O7,(Sr/Ca)SnO3,and(Sr/Ca)Ga2O4, which containd10metals belonging to VA, IVA, and IIIA groups, respectively. Primary intrinsic defects and self-trappedholes in these hosts are revealed and the roles played by them on intrinsic emissions are evaluated. Bismuthions are identified as trivalent dopants and their3P0,1 -> 1S0(referred to asA-band) transition is assignedto account for the ultraviolet emission observed in bismuth-doped (Sr/Ca)Sb2O6, while the visible emissionobserved in (Sr/Ca)Sb2O6:Bi is attributed to Bi3+dopants in the minute amount of (Sr/Ca)2Sb2O7impurities.In Sr2Sb2O7and Ca2Sb2O7with bismuth, the excitation bands are identified as1S0 -> 3P0,1transition of Bi3+,and the observed emission bands are attributed to charge transfer transition (Bi2++h+VBM -> Bi3+)andA-bandtransition (3P0,1 -> 1S0), respectively. Furthermore, the bismuth-related transitions are also well identified in(Sr/Ca)SnO3and (Sr/Ca)Ga2O4and the large Stokes shifts of theA-band transition in (Sr/Ca)Ga2O4arerevealed and analyzed. The insights gained in this work extend our understanding of the properties of intrinsicdefects and the luminescence mechanisms of insulating bismuth-doped ternary oxides.

Automated summary

In this study, first-principles calculations were used to investigate the luminescence properties of four different ternary oxide materials, namely (Sr/Ca)Sb2O6, (Sr/Ca)2Sb2O7, (Sr/Ca)SnO3, and (Sr/Ca)Ga2O4, doped with bismuth ions. The effects of bismuth doping on the materials' luminescence properties were analyzed by studying intrinsic defects and self-trapped holes. The transitions associated with bismuth ions in different materials were also identified. The insights gained from this study are important for understanding the luminescence mechanisms of insulating bismuth-doped ternary oxides.