Near-infrared luminescence in bismuth-doped TlCl crystal

TL;DR

This study investigates near-infrared luminescence in bismuth-doped TlCl crystals through experimental spectral analysis and theoretical modeling, identifying Bi^+__V^-(Cl) centers as the likely luminescence source.

Contribution

It combines experimental spectral measurements with theoretical modeling to identify the specific bismuth-related centers responsible for IR luminescence in TlCl:Bi.

Findings

Two broad IR luminescence bands observed at 1.18 μm and >1.5 μm.

Luminescence lifetime approximately 0.25 ms.

Bi^+__V^-(Cl) centers are likely responsible for IR emission.

Abstract

Experimental and theoretical studies of spectral properties of crystalline TlCl:Bi are performed. Two broad near-infrared luminescence bands with a lifetime about 0.25 ms are observed: a strong band near 1.18 mkm excited by 0.40, 0.45, 0.70 and 0.80 mkm radiation, and a weak band at > 1.5 mkm excited by 0.40 and 0.45 mkm radiation. Computer modeling of Bi-related centers in TlCl lattice suggests that Bi^+__V^-(Cl) center (Bi^+ in Tl site and a negatively charged Cl vacancy in the nearest anion site) is most likely responsible for the IR luminescence.