Organic–inorganic perovskite-type crystals with a linear carboxyl monoamine (HOOCC n H 2n NH 3 ) 2 PbBr 4 (CnCOOH, n = 2, 3, 4, 5, 6, 7, 10, 11) were grown using the temperature gradient method, and the luminescence behaviors were systematically examined. All the crystals had a multiple quantum well structure. Free exciton emissions were detected from the crystals in photoluminescence, and the optimum carbon chain length of the linear carboxyl monoamine was observed in terms of luminescent intensity. Among the fabricated crystals, the C4COOH crystal showed the highest quantum yield of about 28% because of the highest radiative decay rate and the lowest non-radiative decay rate of free exciton emissions. The fabricated crystals also exhibited an emission peak at 419–450 nm upon X-ray irradiation, and the decay time of the fastest scintillation component was about 3–11 ns. Furthermore, their scintillation light yields under gamma-ray were 660–8500 photons/MeV, and the C4COOH crystal exhibited the highest value of the scintillation light yield together with the quantum yield in photoluminescence. In addition, the scintillation light yield of the C4COOH crystal with a quantum yield of 28% was lower than that of the (C 6 H 5 C 2 H 4 NH 3 ) 2 PbBr 4 crystal with a quantum yield of 22% due to the lower energy transfer efficiency in the C4COOH crystal. • Scintillation performance of organic–inorganic perovskite-type crystals with a linear carboxyl monoamine was investigated. • The crystals showed a fast scintillation decay time due to free excitons. • (HOOCC 4 H 8 NH 3 ) 2 PbBr 4 showed the highest quantum yield and scintillation light yield.
Tsubokawa et al. (2026) studied this question.