Electrical switching and memory phenomena observed in redox dendrimer thin films

This article reports on the fabrication of dendrimer molecular thin film sandwich devices with electrical switching and memory properties. The storage media consists of a redox-gradient N,N‴-(1,4-phenylene)bis(N,N′N′N″,N″-pentakis(4-methoxyphenyl)-1,3,5-benzenetriamine) (4AAPD) dendrimer layer sandwiched between two N,N′-diphenyl-N,N′-bis(3-methylphenyl)-1,1′-biphenyl-4,4′-diamine (TPD) thin films. The TPD thin films are used as potential barriers. The 4AAPD layer acts as a potential well where redox-state changes and consequent electrical transitions of the embedded 4AAPD molecules can be effectively triggered. Experimental results indicate that electrical switching could be reproducibly obtained in the dendrimer sandwiches upon crossing a threshold bias voltage. After switching, the device conductivity can be increased more than three orders of magnitude, which is stable for several days in ambient conditions. This work demonstrates the possibility of using solid-state redox-gradient dendrimer layer as information storage media.