Lattice Expansion in Rb-Doped Hybrid Organic–Inorganic Perovskite Crystals Resulting in Smaller Band-Gap and Higher Light-Yield Scintillators
Résumé
Two-dimensional hybrid-organic-inorganic perovskite(2D-HOIP)lead bromide perovskite crystals have demonstrated great potentialas scintillators with high light yields and fast decay times whilealso being low cost with solution-processable materials for wide energyradiation detection. Ion doping has been also shown to be a very promisingavenue for improvements of the scintillation properties of 2D-HOIPcrystals. In this paper, we discuss the effect of rubidium (Rb) dopingon two previously reported 2D-HOIP single crystals, BA(2)PbBr(4) and PEA(2)PbBr(4). We observethat doping the perovskite crystals with Rb ions leads to an expansionof the crystal lattices of the materials, which also leads to narrowingof band gaps down to 84% of the pure compounds. Rb doping of BA(2)PbBr(4) and PEA(2)PbBr(4) showsa broadening in the photoluminescence and scintillation emissionsof both perovskite crystals. Rb doping also leads to faster gamma-rayscintillation decay times, as fast as 4.4 ns, with average decay timedecreases of 15% and 8% for Rb-doped BA(2)PbBr(4) and PEA(2)PbBr(4), respectively, compared to thoseof undoped crystals. The inclusion of Rb ions also leads to a slightlylonger afterglow, with residual scintillation still being below 1%after 5 s at 10 K, for both undoped and Rb-doped perovskite crystals.The light yield of both perovskites is significantly increased byRb doping with improvements of 58% and 25% for BA(2)PbBr(4) and PEA(2)PbBr(4), respectively. This workshows that Rb doping leads to a significant enhancement of the 2D-HOIPcrystal performance, which is of particular significance for highlight yield and fast timing applications, such as photon countingor positron emission tomography.
Two-dimensionalhybrid-organic-inorganic perovskitelead bromide perovskite crystals have demonstrated great potentialas scintillators with high light yields and fast decay times whilealso being low cost with solution-processable materials for wide energyradiation detection. This work shows that Rb doping leads to a significantenhancement of the 2D-HOIP crystal performance, which is of particularsignificance for high light yield and fast timing applications, suchas photon counting or positron emission tomography.