Effects of excitation density on the scintillation properties of organic–inorganic layered perovskite-type compounds

The scintillation properties of organic–inorganic layered perovskite-type compounds were analyzed using pulsed beams having different linear energy transfers (LETs). Initially the decay was slower and then became faster at higher LETs. A possible cause of the slower decay at higher LETs is the competition between the radiative process and trapping at nonradiative sites, resulting in some excitons not being trapped at nonradiative sites at which other excitons have already been trapped at higher LETs. The faster decay at higher LETs is attributed to the interaction of excited states, such as biexciton formation or a nonradiative Auger process. In addition, the LET dependence was most pronounced for (C₆H₅C₂H₄NH₃)₂PbBr₄, whose radiative rate and luminescence quantum efficiency were the highest among the investigated compounds. This result is because the radiative process in this compound, as a major decay process, is more significantly influenced by excited state interactions at higher LETs.