Optical and scintillation characteristics of organic–inorganic layered compounds with a linear alkyl diamine

We prepared organic–inorganic layered perovskite-type compounds having a linear alkyl diamine (NH₃C_nH_2nNH₃)PbCl₄ (n = 6: (1, 6-DHX)PbCl₄, n = 7: (1,7-DHP)PbCl₄, n = 8: (1,8-DIO)PbCl₄, n = 9: (1,9-DIN)PbCl₄, n = 10: (1,10-DID)PbCl₄, n = 11: (1,11-DIU)PbCl₄) and investigated their photoluminescence and scintillation characteristics. A broad band peak that should be attributed to self-trapped excitons (STEs) were observed at 555 nm ((1,6-DHX)PbCl₄), 520 nm ((1,7-DHP)PbCl₄), 525 nm ((1,8-DIO)PbCl₄), 525 nm ((1,9-DIN)PbCl₄), 550 nm ((1,10-DID)PbCl₄), and 530 nm ((1,11-DIU)PbCl₄) in scintillation. Also, they showed a scintillation decay time of 2.2 ns ((1,6-DHX)PbCl₄), 3.0 ns ((1,7-DHP)PbCl₄), 2.8 ns ((1,8-DIO)PbCl₄), 5.6 ns ((1,9-DIN)PbCl₄), 3.5 ns ((1,10-DID)PbCl₄), and 4.7 ns ((1,11-DIU)PbCl₄) due to the STE recombination. Further, the scintillation light yield of the (1,9-DIN)PbCl₄ crystal was the highest (1,200 photons/5.5 MeV-α), and its value was higher than that of an undoped zinc oxide crystal.