Synthesis and characterization of Cs2TeCl6 powder for scintillators

Abstract

We prepare powdered lead-free perovskite Cs₂TeCl₆ using a very simple hydrothermal method. We study in detail the luminescence mechanism and characteristics of Cs₂TeCl₆ (CTC) via both the measurement and phenomenological modelling of emission spectra and decays in a broad temperature interval of 77–500 K. Theoretical DFT calculations of the electronic band structure and exciton state were performed and discussed together with the experimental results. Radioluminescence spectra at room temperature provide an estimate of the CTC overall scintillation efficiency. Both the electron paramagnetic resonance and thermally stimulated luminescence characteristics give an insight into the energy transport in the CTC lattice and the involved charge carrier traps negatively affecting the scintillation performance. The concerted use of a broad portfolio of experimental and theoretical techniques provides a deep insight into the scintillation mechanism of CTC, and its intrinsic limits and bottlenecks. This powder scintillator, in combination with a suitable host matrix, could be an interesting material for double-beta decay detection.