Electroluminescence from monolayer of quantum dots formed by multiple dip-coating processes

Abstract

The monolayer of 4.3 nm-size CdSe (ZnS) core shell quantum dots (QDs) was formed by multiple dip-coating processes to fabricate the electroluminescent device. The particle adsorption was found to depend on both the substrate and the dipping-number. The surface coverage was about 73% on PEDOT and 40% on PVK substrate respectively. Self-assembled monolayer of QDs showed the hexagonal close-packed array by the van der Waals attraction between QDs. The monolayer quantum dots based organic (polymer) light emitting diodes (QD-O(P)LEDs) showed the maximum external quantum eggiciency (eta(ex)) of 0.05% and luminous power efficiency (eta(p)) of 0.45 lm/W in the structure of ITO/PEDOT(40 nm)/PVK(40 nm)/CdSe(ZnS) ADs/BCP(30 nm/Alq(3)(30 nm)/Mg: Ag/Ag. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim