Growth and characterization of highly efficient Cs3Cu2I5 single crystal for γ-ray detection

Metal halide perovskites, particularly zero-dimensional (0D) variants, have garnered significant attention as scintillator materials for various applications such as $\gamma$-ray spectroscopy, X-ray imaging, and security. Among these, Cs${}_3$Cu${}_2$I${}_5$ has emerged as a promising candidate owing to its exceptional characteristics, such as good energy resolution, high light output, and high stopping power. Although there is sufficient data available on the scintillation properties of Cs${}_3$Cu${}_2$I${}_5$ Single Crystal (SC) grown using various methods, there still remains a scarcity of data on the scintillation properties of SCs grown using solvent evaporation method at room temperature. In the present work, Cs${}_3$Cu${}_2$I${}_5$ SCs have been grown using the solvent evaporation method at room temperature and characterized for their structural, optical, and scintillation properties. The SC shows an orthorhombic structure with a bandgap of 3.58 eV. The optical properties of the SC reveal the existence of Self-Trapped Exciton (STE). The SC exhibits an energy resolution of 5.80 ± 0.05% at 662 keV and a light output of 41,000 photons/MeV, making it suitable for $\gamma$-rays detection. The intrinsic photopeak efficiencies of Cs${}_3$Cu${}_2$I${}_5$ SC for $\gamma$-rays are reported for the first time. GEANT4 simulation toolkit has been used to perform realistic simulations, and the simulated and experimental efficiencies are compared. Simulations show that Cs${}_3$Cu${}_2$I${}_5$ scintillator has twice the efficiency of the NaI:Tl scintillator.