Inkjet printing of luminescent CdTe nanocrystal-polymer composites

Inkjet printing is used to produce well-defined patterns of dots (with diameters of ca. 120 mu m) that are composed of lumines- cent CdTe nanocrystals (NCs) embedded within a poly(vinylalcohol) (PVA) matrix. Addition of ethylene glycol (1-2 vol %) to the aqueous solution of CdTe NCs suppresses the well-known ring-formation effect in inkjet printing leading to exceptionally uniform dots. Atomic force microscopy characterization reveals that in the CdTe NC films the particle-particle interaction could be prevented using inert PVA as a matrix. Combinatorial libraries of CdTe NC-PVA composites with variable NC sizes and polymer/NC ratios are prepared using inkjet printing. These libraries are subsequently characterized using a UV/fluorescence plate reader to determine their luminescent properties. Energy transfer from green-light-emitting to red-light-emitting CdTe NCs in the composite containing green-(2.6 nm diameter) and red-emitting (3.5 nm diameter) NCs are demonstrated.