Printed Nonvolatile Memory for a Sheet-Type Communication System

By using state-of-the-art printing technologies and functional inks, we have demonstrated organic nonvolatile flexible random-access-memory matrices with a nondestructive read-out capability and a time-continuous current output; these functionalities have not been simultaneously achieved even by silicon-based conventional memory. A memory cell comprising three transistors becomes possible with inkjet printing and other solution-based processes, which can use ferroelectric copolymer ink comprising poly(vinylidenefluoride-co-trifluoroethylene) and insulating ink comprising polyimide precursors properly within the planer plastic substrate. A large ldquo1 : 0rdquo current ratio of 10⁵ is observed in air when it is annealed at 135degC , which is sufficiently low to be compatible with many plastic substrates. When stored in air, the ldquo1 : 0rdquo ratio was still 10⁴ after 15 days and 10³ after 5 months, which is sufficient for practical applications. Furthermore, human-scale communication sheets were manufactured as the first demonstration utilizing large-area organic memories.