Luminescence of BaBrI and SrBrI single crystals doped with Eu2+

Abstract

The crystal growth procedure and luminescence properties of pure and Eu 2+ -doped BaBrI and SrBrI crystals are reported. Emission and excitation spectra were recorded under ultraviolet and vacuum ultraviolet excitations. The energy of the first Eu 2+ 4f-5d transition and SrBrI band gap are obtained. The electronic structure calculations were performed within GW approximation as implemented in the Vienna Ab Initio Simulation Package. The energy between lowest Eu 2+ 5d state and the bottom of conduction band are found based on luminescence quenching parameters. The vacuum referred binding energy diagram of lanthanide levels was constructed using the chemical shift model.

Role of electron and hole centers in energy transfer in BaBrI crystals

“…As shown in the inset of Fig. 1, efficiency of F-centers creation decreases during cooling at temperatures about 100 K where intensity of STE band emission grows up [4,5]. This anticorrelation behaviour is similar to observed in alkali halides crystals [8].…”

“…Excitation of Eu 2+ emission in the region of exciton peak [5] can indicate the possibility for energy transfer from exciton to Eu 2+ ions as well as in LaBr 3 :Ce, where resonance exciton energy transfer is dominant [14]. Absorption of 4f-5d transition of Eu 2+ ions and exciton emission spectra overlap in BaBrI crystals (Fig.4).…”

“…Theoretically these crystals could reach a higher luminosity, therefore further optimization toward improvements in the scintillation properties of this material should be possible. Thereby, it is necessary to study excitons [4,5], electron and hole centers and their role in energy transfer to emission centers.…”

Control of Eu Oxidation State in Y2O3−xSx:Eu Thin-Film Phosphors Prepared by Atomic Layer Deposition: A Structural and Photoluminescence Study

“…It is known for its broad emission band between ultraviolet and red, where the dominant emission of Eu 2+ ions is attributed to the 4 f 6 5 d 1 → 4 f 7 transition [7]. Many papers have reported Eu 2+ -doped material systems such as fluorides [8], chlorides [9], bromides [10], oxides [11], selenides [12], iodides [13], nitrides [14], and sulfides [15]. Because Eu 2+ is highly dependent on the environment, each material emits in a specific range [7].…”

Выращивание и исследование сцинтилляционных свойств кристаллов BaBrI, активированных ионами самария

“…В работах [7][8][9] нами были рассмотрены аспекты выращивания кристаллов BaBrI, BaClI, SrBrI и приведены результаты исследования оптических и сцинтилляционных свойств этих кристаллов, активированных ионами европия и церия. При анализе спектров люминесценции, измеренных при рентгеновском возбуждении, были сделаны предположения о возможных механизмах переноса энергии.…”