ИСТИНА

The structure and photoluminescent (PL) properties of novel binuclear carboxylate (pivalate) complexes of rare earth (RE) elements – Eu, Sm, Tb, Dy and Gd – were comprehensively studied from the point of view of their possible application as a basis for organic light-emitting diodes, where the function of light emission is devolved to the RE ions. The main advantages of such metalorganic complexes are: low cost and relative simplicity of the synthesis process, easiness of thin films formation by means of evaporation or from solution, high quantum yield, opportunity to build up the complexes with multiple RE ions and, thus, to control the spectral composition of emission. Five sets of samples with varied organic ligands – RE ions coordination environment – were synthesized. The influence of complexes structure on the efficiency of RE ions luminescence is shown by means of PL spectroscopy conducted using both fluorescence lamp and different lasers as an excitation source. PL excitation spectra measurements were carried out to clarify the RE ions excitation mechanisms and energy transfer processes. In addition, heterometallic complexes with two different RE ions were fabricated in order to investigate the sensitization effects between the ions. It is shown that such effects, detected by PL spectroscopy, allows one to clarify the molecules composition. Relative quantum yield measurements were performed using the ethanolic solution of Rhodamin 6G as a reference.