Seeded Growth and Scintillation Properties of Cs3Cu2I5 Perovskite Crystals by the Vertical Bridgman Method

Copper halide perovskite Cs₃Cu₂I₅ has attracted great interest due to its excellent scintillation properties, while it is rather challenging to grow large-size bulk crystals. Herein, the seeded growth of Cs₃Cu₂I₅ crystals are investigated by the vertical Bridgman method. Initially, Cs₃Cu₂I₅ crystal is grown by spontaneous nucleation in a sealed quartz tube. Some Cs₃Cu₂I₅ grains are processed into cylinders for the following seeded growth. Black Cs₃Cu₂I₅ bulk crystal is obtained from the Pt crucible with a seed well in the air, with a dimension of Φ25 mm × 60mm and a <131> preferred growth orientation. The existence of I₂ is possibly contributed to the crystal blackening. Using isodiametric seed, transparent Cs₃Cu₂I₅ crystal wafers with dimensions over 20 mm are successfully grown under vacuum. The absorption edge of the Cs₃Cu₂I₅ crystal is located at ≈330 nm. The photoluminescence of the crystal is centered at 445 nm, featuring a primary decay time of 850.88 ns (83.76%). It displays a significant light yield of 37,000 photons per MeV and an energy resolution of 5.1% at 662 keV, when subjected to γ-ray radiation. The results reveal the feasibility of seeded growth of Cs₃Cu₂I₅ crystals for potential scintillation applications.