Synthesis, Characterization, and Memory Performance of Two Phenazine/Triphenylamine-Based Organic Small Molecules through Donor-Acceptor Design

Two organic small molecule memory materials, TPA-2BIPs and TPA-3BIPs, containing triphenylamine (TPA) as a donor and 4,11-bis((triisopropylsilyl)ethynyl)-1H-imidazo[4,5-b]phenazine (BIP) units as acceptors have been synthesized and characterized. Sandwich-structure memory devices based on these two molecules have been fabricated and the as-fabricated devices displayed similar switching behavior but different ON/OFF ratios. The analysis of AFM images indicates that increasing the numbers of acceptors changes the stacking of molecules in the solid state, which results in different morphology and microstructures in films. Although the switching behavior is not significantly different with increasing acceptor moieties, more acceptor groups do help to enhance the stacking of the molecules in the solid state to generate more consistent switching performance.