The investigation of the luminescent structure of thallium-doped cesium iodide (CsI:Tl) basing on the first-principles coupled with spectral analysis

The luminescent structure of thallium-doped cesium iodide (CsI:Tl) and the behavior of electrons during luminescence are studied at great length based on the conventional first-principles calculation combined with ordinary spectroscopic analysis befittingly in this work. The hybrid functionals based on a screened Coulomb potential (HSE) is used to visualize the energy band structure of the experimental sample’s system, and the corresponding relationship between the transition behavior of CsI:Tl energy levels and the spectrum is studied more accurately. We show the complete energy conversion process clearly, which involves the crystal beginning to receive the energy of a photon until the moment of de-excitation. All the fluorescence process is completed by Tl+ ions that replace Cs+ ions. Our results verify and complement the previous theories and potentially provide important references for the adjustment and design of the detectors and imaging equipment in different fields.