Near-infrared photoluminescence spectra in Bi-doped CsI crystal

Evidence for Bi-valence conversions and Bi ion aggregation

Liangbi Su, Hengyu Zhao, Hongjun Li, Lihe Zheng, Xiao Fan, Xiantao Jiang, Huili Tang, Guohao Ren, Jun Xu*, Witold Ryba-Romanowski, Radoslaw Lisiecki, Piotr Solarz

*Corresponding author for this work

Research output: Contribution to journalArticle

36 Citations (Scopus)


Bi-doped CsI crystals exhibited near-infrared ultra-broadband photoluminescence around 1216 nm and 1560 nm, depending on the bismuth doping levels, which were ascribed to Bi+ and Bi2 + centers, respectively. The crystal chemistry of the Bi3+ to Bi+ reduction and Bi2 + dimer formation in CsI lattice were investigated. Thermal treatments including annealing and quenching were carried out to study the thermal behaviors of the two emission bands. The evolution of absorption and emission spectra of Bi:CsI crystals indicating the Bi-aggregation and valence conversions under thermal activation. The process of Bi aggregation was observed to be a second-order reaction with activation energy of 0.33 eV. Bi2 + was identified as the origin of the 1560 nm emission band with ESR spectra. A simple lattice structure diagram was developed to illustrate the physical processes in Bi:CsI crystals induced by thermal activation.

Original languageEnglish
Pages (from-to)757-764
Number of pages8
JournalOptical Materials Express
Issue number6
Publication statusPublished - 2012
Externally publishedYes

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