[Characterization and photoluminescence properties of an azomethin-zinc complex]

A Schiff base organic metal complex, Bis(salicylidene)-1,2-phenylenediam-ine Zinc(II) with high purity, was synthesized and purified by vacuum sublimation. Its structure, thermal stability and energy band structure were investigated by element analysis, FTIR spectra, TG-DTA curve, UV-Vis absorption spectra, fluorescece emission spectra and PL spectra. Experimental results showed that the complex is a thermally stable, polycrystalline material, with glass temperature and decomposition temperature being 183 and 449 degrees C, respectively. In its infrared spectrum, a high intensity band was at about 1 385 cm(-1). This band was typical of the conjugated C=N stretching vibration, which shifted to higher frequency in relation to the free ligand of salicylaldehyde with 1,2-phenylenediamine. The new bnd at 529 cm(-1) was assigned to Zn-O stretching vibration. Its UV absorption bands were at about 297 and 406 nm, and its tetrahydrofuran solution emitted intensive blue-green fluorescence at the peak wavelength of 508 nm. The absorption band at about 406 nm can be assigned to the intrinsic absorption of C=N. Its optical gap was about 2.62 eV, which was determined by the intrinsic absorption band edge of the complex in tetrahydrofuran solution. Under UV excitation at 365 nm, the complex in film emitted yellow-green fluorescence with the maximum emission peak at 562 nm and a full-width at half-maximum of 48.5 nm in PL spectra. Finally, yellow organic light-emitting devices using this complex as the emissive layer were fabricated and investigated.