Effect of commensurate lithium doping on the scintillation of two-dimensional perovskite crystals

Abstract

Two-dimensional (2D) hybrid lead bromide perovskites are candidates for high light yield, fast scintillators. In this paper, we discuss the effect of commensurate Lithium (Li)-doping (1 : 1 Li : Pb precursor ratio) on the scintillation properties of two previously reported high light yield 2D-perovskite crystals, PEA₂PbBr₄ and BA₂PbBr₄. The effect of Li, e.g. light yield enhancement, is more prominent in PEA₂PbBr₄ compared to BA₂PbBr₄. Both perovskite crystals show a broadening of the radioluminescence spectrum and a slightly longer afterglow, with residual scintillation below 2% after 5 s for both materials. The effects of Li on the negative thermal quenching exhibited by the perovskites are also discussed. Li doping increases the light yield of PEA₂PbBr₄ by 78% and both perovskite materials show an improvement in their energy resolutions, with a record of 7.7% at 662 keV for the Li-doped PEA₂PbBr₄. Both perovskite crystals also show very fast gamma-ray excited scintillation decays, with average times of 12.9 ns and 8.0 ns for PEA₂PbBr₄ and BA₂PbBr₄, respectively. This work shows that Li doping brings a significant improvement of the perovskite performance, making the perovskites more competitive for fast, high light yield applications in the medical, security or industrial sectors.