Br-substituent effect on photoluminescence and scintillation properties of (C6H5C2H4NH3)2PbCl4 perovskite-type compounds

The photoluminescence and scintillation properties of n-bromophenethylammonium lead chloride ((n-BrPEA)2PbCl4) (n = 4, 3, and 2) and phenethylammonium lead chloride ((PEA)2PbCl4) have been investigated. All the samples showed broad emission peaks at 400–700 nm upon excitation by UV light or X-ray. The decay time constants of 8–28 ns were obtained which originated from the recombination of self-trapped exciton (STE) within inorganic layers. The afterglow levels at 20 ms after 2 ms of X-ray irradiation of (4-BrPEA)2PbCl4 and (3-BrPEA)2PbCl4 (76 and 55 ppm) were better than (PEA)2PbCl4 (379 ppm). The light yield of (4-BrPEA)2PbCl4 (3100 photons/5.5 MeV-α) was higher than (PEA)2PbCl4 (1400 photons/5.5 MeV-α).