Tape Casting of ITO Green Tapes for Flexible Electroluminescent Lamps

Indium tin oxide ( ITO ) is a widely applied optoelectronic material. However, conventionally, it is deposited via cost‐ and energy‐intensive physical vapor deposition processes ( PVD ) like sputtering, resulting in rather brittle layers. In this report, the tape casting process is presented as an alternative processing route for the manufacture of transparent, conductive ITO layers. Tape casting is a particle‐based technique, thus ITO nano‐particles are first dispersed and stabilized in organic solvents. Subsequently, slurries are prepared using polyvinyl butyral binder and benzyl phthalate plasticizer. The rheological behavior of the slurries is analyzed and adapted to the tape casting process. After tape casting, the ITO green tapes are characterized concerning their electrical and optical behavior. Optical transmission up to 75% and electrical resistances down to 2 Ω·cm are reached without any further treatment. The ITO layers which exhibit such values are already suitable for applications in certain electronic devices. In this study, the applicability of the ITO green tapes is demonstrated by the assembly of functional, fully flexible electroluminescent lamps, which are laminated using the ITO green tapes as well as other functional green tapes in the as‐deposited state.