Formation of dynamic metallo-copolymers by inkjet printing: towards white-emitting materials

The variation of the central chromophore in bisterpyridine ZnII coordination polymers allowed the assembly of blue-, green- and red-emitting materials. The dynamic nature of the ZnII complex enabled the systematic assembly of a library of statistical copolymers in an efficient way by simply mixing the respective homopolymer solutions. Depending on the ratios used and the consequent energy transfer processes, the resulting emission colors can be tailored. The kinetic lability of the ZnII bisterpyridine polymers was, moreover, utilized to assemble thin films of statistical copolymers in a simple and material-saving manner by inkjet printing. For this purpose, the pure color inks were printed separately on top of each other, followed by one solvent layer to enable the assembly of statistical copolymers. The emission spectra of the resulting films are bathochromically shifted, due to aggregation of the chromophores. The obtained data allowed an estimation of CIE coordinates of the emission color for most ratios of the three polymers used and, thereby, to produce tailor-made emission colors.