Boosting luminescent decay and high-energy particle discrimination in 2D perovskite crystals through Nd³⁺ induced intralayer confinement

Fast-response scintillators play a crucial role in rapid radiation detection, wherein two-dimensional (2D) perovskites have exhibited substantial potential. Enhancing the carrier confinement within 2D perovskites has been demonstrated to be effective in accelerating their luminescence decay. Despite extensive research employing carrier confinement in the interlayer direction, confinement from the inorganic layers remains relatively unexplored. In this study, intralayer carrier confinement in 2D perovskites is achieved through neodymium (Nd) doping. Centimeter-scale phenethylammonium lead bromide (PEA₂PbBr₄, PPB) single crystals doped with Nd³⁺ are fabricated via a solution-based method. Compared to the undoped counterparts, their photoluminescence (PL) decay is markedly accelerated. Notably, the reduction in decay time is more pronounced for α rays than for γ rays, enabling the doped PPB to exhibit distinct luminescent decay characteristics for α and γ rays. This property is verified through the waveforms of single α particles and γ photons, highlighting the potential for enhanced pulse shape discrimination (PSD) between different radiation types. First-principles calculations reveal that Nd³⁺ doped PPB exhibits a higher effective mass and enhanced carrier localization, signifying stronger carrier confinement. This study elucidates the impact of Nd³⁺ doping on reducing the luminescent lifetime of 2D perovskite single crystals, and offers an approach to differentially regulating their scintillating decay response for high-energy particle discrimination.