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Rationalizing the Photoluminescence of Bi3+ and Sb3+ in Double Perovskite Halide Crystals
Ist Teil von
Journal of physical chemistry. C, 2021-12, Vol.125 (48), p.26670-26678
Ort / Verlag
American Chemical Society
Erscheinungsjahr
2021
Link zum Volltext
Quelle
Alma/SFX Local Collection
Beschreibungen/Notizen
Bi- and Sb-doped halide perovskites have been widely reported for their high absorption coefficients, bright emission, and impressive photoluminescence quantum yields. However, several different transition processes can be involved and the mechanisms have not been well understood. We present first-principles calculations with hybrid density functionals on a variety of representative Bi- and Sb-doped chloride systems to resolve these problems and rationalize behaviors. The results show that excitation and emission energies are well predicted in general, and the latter shows a good correlation with the metal–Cl bond length in the host. The remarkably different manifestations of Sb3+ and Bi3+ in hosts with In and Ag and the emission energies are predicted and well interpreted with calculated relaxation processes. Negatively charged neighboring cation-vacancy compensators greatly uplift defect levels but reduce sp → s 2 emission energies. In contrast, a positively charged neighboring anion vacancy downshifts the defect levels and reduces the sp → s 2 emission energies in both Bi3+ and Sb3+. The results obtained provide a significant insight in understanding the photoluminescence processes and excited-state dynamics of chloride double perovskites activated by Bi3+ and Sb3+, as well as rock-salt and K2PtCl6-type systems, and inspire the revelation of the mechanisms of other luminescent materials containing ions with a lone ns 2 pair.