Synthesis and characterization of a blue light emitting material with high thermal stability

We synthesized 2,2´,7,7´-tetrapyren-1-yl-9,9´-spirobi-fluorene (TPSBF), a deep blue emitter featuring four identical emitting pyrene units linked around a stable spirobifluorene core. The TPSBF exhibits a high fluorescence yield, extreme thermal stability and a high glass transition temperature. The tetrahedral nature of the carbon atom at the spiro center preserves the optical and electrochemical characteristics of the pristine pyrene units. A blue organic light emitting diode system having the configuration indium tin oxide/ poly(3,4-ethylenedioxythio-phene):poly(styrenesul-fonate)(50 nm)/ polyvinylcarbazole: TPSBF (43%) (90 nm)/4,7-diphenyl-1,10-phenanthroline (30 nm)/LiF (1 nm)/Al (200 nm) exhibited a maximum luminance of 4130 cd/m² at 12 V, CIE coordinates of (0.16, 0.16), and current and power efficiencies of 1.9 cd/A and 0.9 lm/W, respectively, at 23 mA/cm².