Synthesis And Properties Of Novel Star-shaped Fluorene Derivatives For Light-Emitting Materials In OLED

First, a series of star-shaped fluorene derivatives 4a and 4b were designed and synthesized through Sonogashira reaction and cyclotrimerization reactions. Then 4b was functionalized through Friedel-Crafts reaction and Friedl?nder reaction and compound 6 was synthesized with quinoline in the end unit. They were all characterized by ¹H NMR, ¹³C NMR, Mass Spectra and elemental analysis. All these had good solubility. Compound 4a, 4b and 6 performed good thermal stability and the temperature at 5% weight loss were 492.6℃, 460.6℃and 457.7℃, respectively and the melting point were 244.8℃, 321.0℃and 235.8℃. The photoluminescence (PL) peaks of compound 4a, 4b and 6 presented at 368nm, 369nm and 416nm in CH₂Cl₂, at 357nm, 381nm and 416nm in film, respectively. The small red-shift between the solution and film emission spectra revealed the absence of the molecular aggregation in the solid film, which was attributed to the star-shaped structure. The EA of the 4a, 4b and 6 were -3.04eV, -2.88eV and -2.95eV and the Ip were -5.75eV, -5.80eV and -5.4eV. The EA and Ip value were very similar to Alq3, a general electron transport material, and compound 6 might be a good electron transport material and emitting material. The devices of ITO/NPB/4a/Alq₃/Mg:Ag and ITO/4b/Alq₃/Mg:Ag showed a brightness of 4261 cd/m² at 15V and 1800 cd/m² at 15V, the maximal efficiency 0.602 lm/W and 0.48 lm/W, which suggested a favorable emitting material and hole-transport material used in OLED.Another part of the thesis was synthesis the fluorene derivatives-based compound 12 which contained the quinoxaline units. It was characterized by 1H NMR, 13C NMR, Mass Spectra and elemental analysis. The thermal stabilities determined by TGA and DSC were 477.5℃(5% weight loss) and 140℃(melting point). The PL peaks appeared at 447nm (in CH₂Cl₂) and 447nm, 375nm (in film), which suggested that fluorescence quenching be...