Confocal mapping of stable room-temperature emission centers in gadolinium doped vacancy-ordered double halide perovskite, Gd:Cs2SnCl6

The recent advancement in bandgap engineering through controlled doping has widen the prospect of vacancy ordered double halide perovskites (VO DHPs) by conferring them with designable optoelectronic properties. Here, we report confocal mapping of Gd doped Cs2SnCl6 along with the macroscopic photoluminescence studies. The insertion of Gd3+ ions into the crystal structure facilitates an additional stable room temperature low in-tensity PL emission at ca. 615 nm (-2.0 eV) in addition to the major emission at ca. 445 nm (-2.7 eV) due to the creation of defect states. Both the pristine (Cs2SnCl6) and Gd:Cs2SnCl6 exhibit crystalline cubic structure with the space group of Fm3m. The Rietveld refinement correlates well with the experimental X-ray diffraction data, while the SEM studies confirm the anisotropic growth, forming large micron sized octahedral structures of pristine (>20 & mu;m) and partly distorted crystals of Gd:Cs2SnCl6 (<5 & mu;m). This study enhances the understanding of hitherto unknown 2nd emission at room temperature of larger crystals of Gd:Cs2SnCl6 having implications in quantum photonics.