Effects of solvent on fabrication of polymeric light emitting devices

摘要

Different solvents including toluene, chloroform and their mixture have been used in fabricating poly(9,9-dioctylfluorency-2,7-diyl) (PFO)-based polymeric light emitting devices (PLED). Three photoluminescence (PL) and electroluminescence (EL) emission components at 420, 440 and 470 nm were observed, with the distribution of PL spectra different from that for EL. The magnitude of the 470 nm component increases in EL spectra while decreases in PL spectra with the introduction of chloroform. On-set voltage of the PLEDs from the toluene solution is the lowest and is the highest from chloroform. The observed results suggested that the difference in solvent polarity, reactivity and vaporizing rate has strong effect on the polymers in solutions, the underlying layer and the cast emissive layer. PLEDs of poly[2-(5-cyano-5-methylhexyloxy)-1,4-phenylene] (CN-PPP) were also made and the results will be compared with that from PFO.