Effect of single atom substitution in benzochalcogendiazole acceptors on the performance of ternary memory devices

Abstract

Herein, three conjugated organic molecules comprised of the diethylamine donor, pyrimidine and benzochalcogenodiazole acceptors (where the chalcogen atoms are varied from O, S to Se), named PBOP, PBTP, and PBSeP, were synthesized and fabricated into resistive random access memory devices. Structural analysis and theoretical calculations show that the three molecules have almost the same crystal structures and orientations in the film state but different backbone planarities, electron affinities, intra- and intermolecular interactions, which tune the molecular packing and optical absorption. All the compounds exhibited non-volatile ternary memory characteristics while PBOP showed the lowest switching threshold voltages (1.2 V) and highest I_on/I_off ratios (10⁵ and 10³).