Structural peculiarities, point defects and luminescence in Bi-doped CsCdX3 (X = Cl, Br) single crystals.

Promising luminescent CsCd X 3 (X = Cl, Br) single crystals, both nominally-pure and doped with bismuth, have been studied comprehensively by X-ray diffraction, X-ray synchrotron radiation, and X-ray absorption spectroscopy. Crystal structure refinement shows vacancies in the Cs crystallographic site and partial substitution of Cd2+ ions by Bi3+ ones in both CsCdCl 3 and CsCdBr 3 (point defects Bi Cd •), which is consistent with the results of X-ray absorption spectroscopy. The assumed presence of Bi1+ ions in the Cs1+ sites of doped CsCd X 3 (X = Cl, Br) crystals is not confirmed. In the photoluminescence spectra of Bi-doped CsCdCl 3 and CsCdBr 3 crystals, a single band in the near-IR spectral range with a maximum around 1000 nm is caused by point defects Bi Cd •. Photoluminescence spectra and decay kinetics of Bi-doped CsCd X 3 (X = Cl, Br) indicate their promising use as luminescent materials. • Bi-doped CsCd X 3 (X = Cl, Br) crystals were grown by the Bridgman-Stockbarger method. • Crystal structures were refined using X-ray diffraction and synchrotron radiation. • Vacancies in the Cs site and a partial substitution of Cd2+ by Bi3+ were found. • The photoluminescence band around 1000 nm is caused by Bi Cd.• point defects. • Photoluminescence studies and decay kinetics indicate the luminescent properties. [ABSTRACT FROM AUTHOR]