Highly Luminescent Salts Containing Well-Shielded Lanthanide-Centered Complex Anions and Bulky Imidazolium Countercations

In this paper, we report on the syntheses, structures, and characterization of four molten salts containing imidazolium cations and europium(III)- or terbium(III)-centered complex anions. In the complex anions, the lanthanide centers are wrapped by four pseudodiketonate anionic ligands, which prevent them from contacting with high-frequency oscillators and allow them to show intense characteristic europium(III) or terbium(III) emission, small line widths, high color purity, high quantum yields (30−49%), and long decay times (\u3e2 ms)

Comparison of Optical Properties of Eu3+\text{}^{3+} Ions in the Silica Gel Glasses Obtained by Different Preparation Techniques

Silica sol-gel glasses doped with Eu$\text{}^{3+}$ ions were obtained by different preparation techniques. The absorption, emission and excitation spectra of the obtained glasses were measured in the range of 77-300 K. The energy level diagrams of Eu$\text{}^{3+}$ ions were derived. An intensity analysis of f-f transitions was performed. In particular, polymeric structure behaviour of europium compounds entrapped in silica gels glasses was temperature controlled during the preparation of glasses. Their optical properties were investigated