Influence of polymer matrix on the luminescence of phosphor based printable electroluminescent materials and devices

This work reports on the development of printable electroluminescent materials and devices based on different polymer matrixes. For this purpose, different contents of zinc sulfide co-doped with copper (ZnS:Cu) particles (20, 40 and 60% wt.) were incorporated into styrene-ethylene-butylene-styrene (SEBS) (UV resistance and stretchable), poly(vinylidene fluoride (PVDF) (thermal, chemical and UV stability and high dielectric constant), poly(vinyl alcohol (PVA) and carrageenan (water soluble polymers) in order to evaluate the influence of the polymer matrix on the functional performance of the materials. ZnS:Cu particles were incorporated into the different matrixes by solvent casting. The morphology of the composites was evaluated, displaying the ZnS:Cu/PVDF composite the better filler dispersion with respect to the other polymers. Independently of the polymer matrix, no chemical changes occur in the polymer chemical properties, but a shift to lower temperatures is observed in the melting temperature with increasing filler content. The printability of the different ZnS:Cu/polymer materials is demonstrated and integrated into functional devices, presenting SEBS the highest luminance values (31 cd m−2) upon an applied AC voltage of 250V at a frequency of 2.6 kHz.