Speaker
Description
While three-dimensional (3D) halide perovskites demonstrate potential for X-ray detection, their commercial feasibility is severely constrained by ion migration, which induces baseline drift and environmental instability. Two-dimensional (2D layered perovskite such as (BA)2PbBr4 offer an alternative by providing physical barriers to halide ion diffusion and exploiting low dielectric screening to obtain high exciton binding energies for efficient radiative recombination. In this study, the fabrication of 2D (BA)2PbBr4 film using a scalable, solvent-free single-source vacuum deposition (SSVD) technique produces an ultra-thick film (10.5 ± 4.0µm), which records a sensitivity of 2464 µC Gy⁻¹ cm⁻² and a limit of detection 66 nGy s⁻¹. To understand the parameters that influence film quality, the effects of substrate temperature, source-substrate distance and precursor mass on film morphology and stoichiometry are systematically investigated. The findings reveal that increasing substrate temperature above 40°C lowers the sticking coefficient drastically, leading to extensive void formation up to 90% at 60 °C and severe stoichiometric degradation. Although a shorter source- substrate distance introduces a structural trade-off through increased surface roughness, the high deposition flux ensures full film surface coverage and a near-ideal Br/Pb stoichiometric ratio. This work highlights that precise SSVD parameter optimisation is important for fabricating a high-stability and scalable X-ray perovskite scintillator.