Photoluminescence and Scintillation Mechanism of Cs 4 PbBr 6

Small bandgap scintillators have gained significant attention in recent years. Especially Cs PbBr is an interesting material, mitigating the small Stokes shift-related problem of perovskites like CsPbBr . In this work, optical and scintillation properties of Cs PbBr single crystals are investigated as a function of temperature, with a detailed focus at 10 K. The Cs PbBr single crystals were grown using the vertical Bridgman method. Due to incongruent melting, CsPbBr inclusions are formed, generating a 540 nm emission band. Prepairing Cs PbBr via solid-state synthesis yields CsPbBr -inclusion-free material, showing no green 540 nm emission band. In Cs PbBr samples with and without CsPbBr inclusions, a new emission band at 610 nm ascribed to an unknown defect was found. Based on the presented experiments, an emission mechanism is proposed for Cs PbBr . This shows that both defects and CsPbBr inclusions play a role in the emission behavior of Cs PbBr but only the CsPbBr inclusions are responsible for the 540 nm emission.