Photoluminescent (CdSe)ZnS quantum dot-polymethylmethacrylate polymer composite thin films in the visible spectral range

We synthesized (CdSe)ZnS quantum dot (QD)-polymethylmethacrylate (PMMA) polymer composite and fabricated QD-polymer composite films. We produced the CdSe and (CdSe)ZnS QDs by direct colloidal chemical synthesis and the surface-passivation method-an overcoating of the dots with a larger-bandgap material. PMMA is transparent in the visible spectral range and was chosen as the embedding matrix for QDs. A 28%(wt/wt) of PMMA in MMA was the most appropriate concentration to produce a film of good quality and maximize the solubility of quantum dots without phase separation of the QDs from the matrix. We fabricated green or red light emitting (CdSe)ZnS QD-PMMA polymer composite film by combining the green or red light emitting (CdSe)ZnS dots with PMMA of high optical transparency in the visible region and spin-coating the composite solution. The fabricated green light emitting (CdSe)ZnS-PMMA composite film had a good quantum yield of 40% and a narrow emission band at 543 nm with a full width at half maximum of ∼35 nm. A white light emitting device can be fabricated by combining our green/red light emitting QD-polymer composites with a blue light emitting LED as an excitation source. Our QD-polymer composites can be applied to flexible coloured filters, large-area coloured wall-papers and full colour displays