Enhanced intra/intermolecular charge transfer for efficient multilevel resistive memory

Adjustment of molecular structure can effectively improve the organic memory device behaviors due to the optimization of intra/intermolecular interaction and molecular packing motif. However, the intrinsic mechanism of how intermolecular interaction and molecular packing motif affect the device performance needs to be further explored. Herein, we synthesized four new small molecules (X-TEBT) by introducing the alkynyl pi bridges and different substituents (X = H, CN, tBu, OMe) into the backbone of conjugated donor-acceptor molecules, namely, TEBT, CN-TEBT, tBu-TEBT and OMe-TEBT, for solution-processed organic resistive memory. All memory devices displayed nonvolatile write-once-read-many-times (WORM) behaviors with low threshold voltage (Vth), high production yield, and good thermal stability. The champion device (tBu-TEBT) exhibits ternary WORM property with the highest ON2/ON1/OFF ratio and the lowest Vth1 (1.6 V) and Vth2 (2.4 V). More importantly, the single crystal structure of tBu-TEBT was successfully obtained which helped us analyze the origin of the physical mechanism of resistive switching behavior and establish a common structure-property relationship for high performance organic memory. Its excellent properties enable us to perform logic gates and information display functions which offer possibilities as smart sensor in Internet of Things (IoT) application.