Synthesis of Silver Nanoparticles for Organic Bistable Memory Device Applications

Poly (vinyl pyrrolydone) (PVP) capped spherical silver nanoparticles (Ag NPs) were synthesized using polyol process. In this process, silver nitrate (AgNO3) acts as precursor, ethylene glycole (EG) as reducing agent and PVP as capping agent. Field emission scanning electron microscopy images revealed the spherical geometry of nanoparticles with narrow size distribution. The sharp linear absorption band confirmed the high monodispersity in size and shape of nanoparticles. Bistable memory devices were fabricated by embedding synthesized nanoparticles between two tris-(8-hydroxyquinoline)aluminum (Alq3) layers and memory characteristics were studied using current-voltage (I-V) characteristics. When the applied voltage exceeds a threshold value (6.5 V), the device suddenly switches from a low current OFF state to a high current ON state. The device exhibited an ON/OFF current ratio of more than 100 at a read voltage of 4 V. The OFF state of the device could be recovered by applying a negative voltage pulse above -5 V. Applied voltage induced transfer of electrons between Ag NPs and Alq3 layers is proposed to be responsible for switching between different conducting states. Present study indicates that the Ag NPs synthesized using polyol process have strong potential in non-volatile organic memory applications.