title: Role of Au nanoparticles in efficiency enhancement and green band emission quenching of blue polymer light emitting diodes.
abstract: We studied photoluminescence (PL) and electroluminescence (EL) properties of polymer light emitting diodes (PLEDs) constructed with polyconjugated polymers blends containing Au nanoparticles (DA-Au NPs; 5.3 nm +/- 1.1 nm in diameter) capped by dodecylamine. For the blue light emitting polyfluorene polymers, selective quenching of excimer peaks or so-called green bands was observed in PL as well as in EL when they were mixed with small amounts (1-4 wt%) of DA-Au NP. The influence of DA-Au NPs on the light-emitting characteristics of the PLEDs strongly depended on the nature of the matrix polymer, which was particularly conspicuous for the polymers whose emission wavelength matches or overlaps with the surface plasmon resonance wavelength region of Au nanoparticles. Especially, the purity of the blue color emitted by the poly [2,7-(9,9-di-n-dioctylfluorene) (PF) was greatly improved by Au NPs that suppressed the 'green band.' All the PLEDs doped with DA-Au NPs showed enhanced maximum external quantum efficiency and emitted light intensity when compared to undoped counterparts.
authors.affiliation: Division of Chemistry and Molecular Engineering and Center for Electro- and Photo-Responsive Molecules, Korea University, Seoul 136-701, Korea.
authors.forename: Kyungkon
authors.initials: K
authors.lastname: Kim
authors.forename: Byung-Hee
authors.initials: BH
authors.lastname: Sohn
authors.forename: Jung-Il
authors.initials: JI
authors.lastname: Jin
mesh_terms: D000588:Amines / Q000737:chemistry; D003460:Crystallization; D004563:Electrochemistry / Q000379:methods*; D006046:Gold / Q000737:chemistry*; D008027:Light; D008422:Materials Testing; D046529:Microscopy, Electron, Transmission; D008956:Models, Chemical; D049329:Nanostructures / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size; D011108:Polymers / Q000737:chemistry*; D013053:Spectrophotometry; D020349:Surface Plasmon Resonance; D014466:Ultraviolet Rays
chemical_list: D000588:Amines; D011108:Polymers; D006046:Gold; C003935:dodecylamine