Luminescence in colorless, transparent, thermally stable thin films of Eu3+ and Tb3+ beta-diketonates in hybrid inorganic-organic zinc-based sol-gel matrix.

Luminescent zinc-based hybrid inorganic-organic films with rare-earth (RE) complexes have been prepared using a non-alkoxide sol-gel process. The films were fabricated by the dip-coating method starting from zinc acetate dihydrate, rare earth chloride, lactic acid as hydrolytic catalyst, and anhydrous ethanol. The beta-diketones thenoylltrifluoroacetone (Httfa) and dibenzoylmethane (Hdbm) were used as ligands to Eu(3+) and Tb(3+), respectively. After deposition of the first layer, the films were fired at temperatures between 50 and 300 degrees C, in air. Photophysical properties such as excitation, emission and emission, lifetimes were determined for the films obtained in different conditions. Eu(3+)/ttfa and Tb(3+)/dbm films fired at 300 and 250 degrees C, respectively, are still transparent and gave rise to intense emission when excited through the ligand (antenna effect).