Cyan, magenta and yellow TiO2-based hybrid spheres for electrophoretic inks

This study presents an innovative approach for the fabrication of colour electronic inks designed for multi-colour electrophoretic image displays (EPIDs). Hybrid spheres composed of titanium dioxide (TiO 2 ) cores and organic colourants (cyan, magenta, and yellow), then encapsulated by appropriate polymer shells, were synthesized to be integrated into pixel prototypes for EPIDs. Thus, the work involves three main key steps: (i) the preparation of coloured hybrid spherical particles through spray-drying of TiO 2 suspensions with organic inks, (ii) the exploration and the characterization of the pallet of colourations which are accessible for the hybrid spherical particles, (iii) the enhancement of particle stability in EPID fluids thanks to functionalization (silanisation and polymer encapsulation) and surface charge introduction on the hybrid pigment spheres for stability in apolar media. Electrophoretic performance was evaluated in dual-colour display cells. The hybrid particles demonstrated excellent light-harvesting capabilities and colloidal stability. Electrophoretic tests showed promising performance, with alternating surface colourations and sustained optical contrasts over multiple refresh cycles. This research contributes to the development of advanced colour electronic ink technologies for improved electrophoretic displays.