Results on Photoluminescence (PL) studies of KBr1-xI x:TlI (0.01 mol%) mixed crystals grown in
vacuum and open air atmosphere are presented in this paper. PL emission spectra of the mixed
crystals excited in the A-absorption band of KBr:Tl+ exhibited the characteristic emission bands
of Tl+ ions in KBr:Tl+. When excited in the low energy tail of A-band absorption, a broad
asymmetrical emission band around 3.64eV with long tail on the low energy side were observed.
Comparing with earlier reports, excitation bands observed around 4.8, 4.6 and 4.4eV are
attributed to complex thallium centres of the form TlBr6-nIn (n = 0, 1, 2, 3).