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Single crystal of TlCl was doped with NIR photoluminescent univalent bismuth cations by prolonged immersion in liquid bismuth metal. The ion exchange Tl+ + Bi0 ↔ Tl0 + Bi+ at the crystal surface with subsequent Bi+ migration to the bulk are expected to drive the doping process. Contrary with Bi‐doped TlCl crystals, grown by Bridgman method, the ion exchange does not produce the additional nonluminescent bismuth‐containing centers. The investigation of photoluminescence emission and excitation spectra lead to the conclusion, that Bi+ is the main NIR emissive center in Bi‐doped TlCl. Near‐IR photoluminescent univalent bismuth cations can be introduced into TlCl crystal by ion exchange route. [ABSTRACT FROM AUTHOR]

Abstract: Bi+-doped single crystals of triple chloride CsCdCl3 were prepared by the Bridgman method. Bismuth monocation is responsible for characteristic two-peaked absorption feature in visible and long lived NIR luminescence in this crystal. The splitting of the Bi+ lowest electronic states by crystal field is considered. The absorption spectrum is assigned to optical transitions of A→E type in two nonequivalent Bi+ positions of D3h and C3v symmetry. The possibility of Jahn–Teller effect in Bi+ excited states of E type is discussed in relation with absorption and luminescence excitation spectra properties. [Copyright &y& Elsevier]