Synthesis And Properties Of Novel Organic Luminescent Derived From Fluorenes

Metal-chelate complexes have been regarded as the most promising luminescent material forboth high fluorescent quantum yields and excellent stabilities. Kinds of complexes based on flourene,with better luminescent and thermal stability, easier modification and higer fluorescence quantumyields, are now in widespread use.A series of benzothiazole and poly-salen ligands, and their corresponding zinc (Ⅱ) complexeswere synthesized with fluorenes as starting materials.The chemical structure, luminescence properties,thermal stability and electrochemical properties of the complexes were characterized by1H NMR,13CNMR spectra, IR spectra, UV-Vis absorption spectra, fluorescence spectra, thermogravimetricanalysis (TGA) and cyclic voltammetry measurements. The experimental results indicate:1. The benzothiazole and poly-salen ligands had featurable absorption at the wavelength between230-400nm as well as eradiation at the wavelength400nm and500-560nm for characteristic peaks,coordinated with metal leading to the featurable absorption’s and emission peak’s shift.2. The fluorescence quantum yields of benzothiazole, poly-salen ligands and their zinc-chelatecomplexes were between73.7-82.3%,39.0-51.3%,74.8-85.6%,44.5-54.4%respectively. Theemissive wavelengths and fluorescent quantum yields of the resulted complexes would be improvedby introducing electron donating groups.3. Cyclic voltammetry revealed that ELUMOand EHOMOof the zinc-chelate complexes were-2.10~-2.69eV and-5.02~-5.21eV, which matched those of the injection and transmission layers well innormal devices. The thermogravitometric analysis showed good thermostability of metal-chelatecomplexes for the decomposition temperature of300oC above.In summary, metal-chelate complexes based on fluorene ligands have the high decompositiontemperature and appropriate energy band gap, which may become high-performance OLED materials.