Wet-chemical preparation of Ce3+-activated K2LaX5 (X=Cl, Br or I) phosphors

There has been a renewed interest in Ce3+-activated halide phosphors due to applications as scintillation detectors, especially for positron emission tomography. For K2LaCl5, the light yield increases and the energy resolution (FWHM) improves with increasing Ce3+ doping. K2LaX5 compounds are also important as laser hosts for the mid-IR range. K2LaCl5:Nd crystals show bright mid-IR luminescence, which makes them a candidate for IR laser materials. Efficient emission in the IR range has also been reported in K2LaCl5:U3+. A one-step, wet chemical process for preparing Ce3+-activated K2LaCl5 phosphor is described. Intense luminescence of Ce3+ can be observed in the as-prepared powders without any heat treatment. The availability of such powders opens up several exciting possibilities, such as growing single crystals without going to the high temperatures required for melting the constituent chlorides, or even obtaining processed, transparent, Ce3+-activated materials without taking recourse to crystal growth. Copyright (C) 2011 John Wiley & Sons, Ltd.