Arylacetylene End-Capped Triarylamine-Based D–A System for Switching from Binary to Ternary Memory Behavior

Introducing a different acceptor into the same molecular backbone with a definite acceptor strength is the key to developing multilevel memory devices. A series of Y-shaped imidazole- and triarylamine-based compounds was designed and synthesized for multilevel data storage. The influence of various donor and acceptor end-cap units on the photophysical, electrochemical, and memory performance was evaluated. The electrochemical analysis reveals a high highest occupied molecular orbital (HOMO) level of around ∼5.0 eV and a low band gap with irreversible anodic peaks (1.05–1.08 V), which indicates facile charge transport in the donor/acceptor end-capped D–A systems. Switching the memory behavior from binary to ternary was achieved by tuning the acceptor strength in the molecular structure. The compounds with the terminal electron-withdrawing groups displayed a ternary memory with an ON/OFF ratio of 10 4 with a long-lasting retention time. tert -Butylphenyl and methoxyphenyl end-capped compounds demonstrated binary memory with a low threshold voltage (−1.42 and −1.38 V) and an ON/OFF ratio of 10 5 . The molecular simulation confirms the charge transfer and trapping mechanism associated with the compound binary/ternary memory behavior. This work demonstrates that slight modification in the molecular structure can change the memory behavior from binary to ternary and renders a new pathway for updating the multilevel storage devices.