Self-absorption and investigation of excited carrier dynamics in two-dimensional perovskite scintillator

Abstract

The PEA2PbBr4 scintillator exhibits varied performance in photoluminescence (PL) and radioluminescence (RL) profiles. PL in the reflectivity mode shows emission peaks at 414 and 434 nm, whereas PL and RL in the transmission mode exhibit only one peak at 434 nm. Temperature-dependent PL spectra measurements confirm that self-absorption contributes to this difference. PEA2PbBr4 displays decay times of 1.3 ns (90%) and 4.4 ns (10%) for PL and 11.5 ns (89%) and 47 ns (11%) for RL. To explain the distinct decay times, we construct two models for simulating laser and radiation excitation and investigate carrier dynamics using non-adiabatic molecular dynamics. Our findings suggest that the relatively long radiative recombination process of carriers contributes to the slow RL decay time.

Epitaxial Welding of 3D and 2D Perovskite Single Crystals for Direct-Indirect Energy-Conversion X-ray Detection and Imaging

“…The 3D/2D/3D structure is illustrated in Figure a, which displays that the 2D SC can effectively inhibit the migration of halide ions in the 3D SC, whereas the 3D SC can absorb the radiation luminescence (RL) of the 2D SC, which improves the energy conversion efficiency of the X-ray and enhances the stability of the detector. A typical 2D perovskite with strong RL, (PEA) 2 PbBr 4 , , was selected as the 2D SC layer in this study, and the well-studied MAPbI 3 perovskite with a high carrier mobility was used as the 3D layer. , Figure b shows the crystal structure of the 3D/2D/3D SC, and because of the low crystallization barrier between the organic ammonium ion and the inorganic BX 6 octahedron, it is easy to epitaxially grow 3D perovskite on the 2D SC. In this study, 2D (PEA) 2 PbBr 4 SCs are grown using the airflow-controlled crystallization method, and a layer of 3D MAPbI 3 is grown on both the top and bottom of the 2D SC via vacuum-assisted epitaxial crystallization, as shown schematically in Figure c.…”