Using a layer-by-layer assembly technique to fabricate multicolored-light- emitting films of CdSe@CdS and CdTe quantum dots

The fabrication of multicolored light-emitting thin films of CdSe@CdS and CdTe quantum dots (QD) were performed using a layer-by-layer assembly technique (LBL). The LBL assembly of of the QDs and PDDA occurred through electrostatic attraction and hydrogen bonding, because the citrate-stabilized CdSe@CdS and MPA-stabilized CdTe QDs possessed negative charges and PDDA (poly(diallyldimethylammonium chloride)) had a positive charge under the assembly conditions. The colors of the films were determined by the FRET efficiency between the two different QDs and their relative amounts. Soft photolithography patterning in conjunction with LBL assembly technique was used to fabricate patterned QD microstructures of different colors on a single ITO substrate. It was found that in aqueous solution the fluorescence intensities of the CdTe and CdSe@CdS QDs were quenched in the presence of AuNPs.