Luminescence of Ce3+ in some chloroaluminates

Chloroaluminate systems are important due to their use in the production of aluminum and sodium metals, in electro-deposition of aluminum alloys, extraction of aromatic hydrocarbons, etc. However, no data on luminescence in these compounds are available. Low melting points and instability due to the high volatility of AlCl3 seem to be deterrents for carrying out such investigations. Synthesis and photoluminescence spectra of Ce3+ activated alkali chloroaluminates and some alkaline earth chloroaluminate phosphors are described for the first time in the present work. A simple wet chemical method is used for the preparation of the phosphor. Very intense emission was observed for LiCl·AlCl3 and NaCl·AlCl3. For the former, the emission attributable to d-f transitions is entirely in the UVA1 (ultraviolet A1) region. The intensity is comparable to that of a commercial phosphor. Ce3+ activated emission in the alkaline earth compounds CaCl2·AlCl3 and MgCl2·2AlCl3 was relatively much weaker.