Optical properties of bismuth-doped TlCdCl3 crystal

Preparation of optical media with NIR luminescent Bi+ impurity centers by ion exchange

“…The maximum of the “red” band in PL excitation spectrum corresponds roughly to the excitation energy from 3 P 0 ground state to the sublevels of 3 P 2 term of Bi + impurity in different halide crystals . The intensity of this band is low because direct photoexcitation of Bi + should be rather ineffective in TlCl, since Bi + impurity in Tl + position is embedded in the crystal field of octahedral symmetry and all the optical transitions between Bi + electronic states within p 2 configuration should be forbidden.…”

“…However, the nature of multiple NIR emissive centers in Bi‐containing glasses is not clear, and it is believed, that the investigation of bismuth‐containing NIR PL centers in crystals can be more informative . The large single crystals is desirable for the characterization of its optical properties and several NIR PL bismuth‐doped halides (RbPb 2 Cl 5 , CsI, CsCdCl 3 , CsCdBr 3 , TlCdCl 3 , TlCl) were prepared in the form of the relatively large single crystals. It was assumed, that bismuth monocation Bi + is the main NIR PL emitter in these halides, although in the case of TlCl the more complicated emissive center was postulated .…”

“…The large single crystals is desirable for the characterization of its optical properties and several NIR PL bismuth‐doped halides (RbPb 2 Cl 5 , CsI, CsCdCl 3 , CsCdBr 3 , TlCdCl 3 , TlCl) were prepared in the form of the relatively large single crystals. It was assumed, that bismuth monocation Bi + is the main NIR PL emitter in these halides, although in the case of TlCl the more complicated emissive center was postulated . Also, the additional bismuth‐containing impurity center (or centers) with absorption bands at 530, 450, 720, and 1000 nm was reported in Bi‐doped TlCl, grown by Bridgman method .…”

Influence of monovalent Bi+ doping on real composition, point defects, and photoluminescence in TlCdCl3 and TlCdI3 single crystals

“…The unit cell parameters of TlCdI 3 :Bi single crystals, determined by both XRD and SCXRD analyses (Table 1), are smaller than those found for the undoped TlCdI 3 crystals [30]. It follows that the Tl + ions (r Tl VIII = 1.59 Å [31]; r is a cation radius) are not replaced by the Bi + ones (r Bi VIII = 1.774 Å [12]), as was supposed [17,[32][33][34][35][36][37][38]. The refinement of the Tl site occupancy showed its decrease, which also evidences an absence of the Bi + ions in this site (the form factor or atomic factor is proportional to the atomic number), but indicates the presence of vacancies ( Table 1).…”

“…The differences are related to the number of photoluminescence bands (there are two bands for TlCdCl 3 :Bi, and one band for TlCdI 3 :Bi) and to the shift of the band with λ~1200 nm to~1253 and~1175 nm for the TlCdCl 3 :Bi and TlCdI 3 :Bi, respectively (Fig. 5) [38,39].…”