Organo-modified ZnO nanoparticles: tuning of the optical properties for PLED device fabrication

Abstract

Organo-modified ZnO nanoparticles were synthesized in basic media through a co-precipitation method, starting from a solution of zinc acetate in methanol and three different organosilane species (i.e. 3-aminopropyl-triethoxy silane, isobutyl-triethoxy silane and phenyl-triethoxy silane). Following this one-pot procedure, highly luminescent nanoparticles with organic species covalently bound on the ZnO surface were successfully obtained. The samples were studied through a multidisciplinary approach aiming to define their structural, morphological and surface properties in relation to the different organosilanes used for the ZnO preparation. Furthermore, a comparison of the optical features of the produced materials was also attained. Among the different ZnO nanoparticles, those functionalized with isobutyl groups were added to a light-emitting poly(p-phenylene vinylene) derivative copolymer (Super Yellow of the Merck Company) in order to obtain a novel composite material with enhanced emission properties. The latter was used as an active layer in the fabrication of a highly efficient Polymeric Light Emitting Diode (PLED) device.

White Electroluminescence from Aluminum Zinc Oxide Embedded in Poly(9‐vinylcarbazole)

“…Nonetheless, the importance of its use as emissive layer (EML) for white light generation was recognized and LEDs were built having ZnO films deposited by low‐pressure thermal evaporation . Recently, polymer/inorganic hybrid LED having ZnO nanoparticles and nanorods, Fe 3 O 4 and TiO 2 , for example, were obtained, because of their enhanced optical and electrical properties in comparison to pure polymer system …”

“…Previously, a combined PL due to polyfluorene and ZnO band‐edge emission, with remarkable intensity enhancement, was demonstrated for polyfluorene/AZO composites . Costelano and co‐workers reported a hybrid light‐emitting diode based on organic‐modified ZnO_NPs/poly(phenylene vinylene) (PPV) nanocomposites. They observed the green‐yellow emission from PPV, at the same time as ZnO_NPs enhanced the PPV emission intensity due to the reduction in polymer chain aggregation.…”

“…[2] Recently, polymer/inorganic hybrid LED having ZnO nanoparticles and nanorods, Fe 3 O 4 and TiO 2 , for example, were obtained, because of their enhanced optical and electrical properties in comparison to pure polymer system. [4][5][6][7] WOLEDs can be classified according to the emitters used in all-fluorescent, all-phosphorescent and those presenting both, fluorescent and phosphorescent emitters. [8] Recent high efficient WOLEDs includes intrinsically thermally activated delayed fluorescent (TADF) compound confined by n and p layers, forming p-i-n structure, separated fluorescent and phosphorescent emitting layers to avoid exciton quenching, luminogens with aggregation-induced emission (AIE) characteristic that improve rather than quench the emission.…”