Ternary Memory Devices Based on Copolymers of Dipyrido[3,2-a:2′,3′-c]phenazine Acceptor and Multiple Donors

Abstract

Donor–acceptor (D–A) conjugated polymers have exhibited their utility in the fabrication of memory devices with high information storage capacity. The device performance can be effectively regulated through the appropriate pairing of the acceptor and donor moieties. Six different D–A conjugated polymers, featuring varied structures, were synthesized by using the Suzuki coupling reaction. Donor molecules such as fluorene, carbazole, and 4′-methoxytriphenylamine, as well as the acceptor molecule dipyrido[3,2-a:2′,3′-c]phenazine (dppz), were employed in this process. Interestingly, it was observed that simply increasing the ratio of donor groups did not yield improvements in device performance. On the other hand, the memory devices fabricated using these polymers as the active layers exhibited favorable ternary resistance memory behavior. Specifically, the first and second threshold voltages were impressively low, at −0.40 and −0.75 V, respectively. The OFF: ON1: ON2 current ratio reached an outstanding ratio of 1:102.90:105.47. Moreover, these devices demonstrated excellent stability with a retention time of 104 s and an endurance of 103 cycles. In conclusion, this study successfully synthesized D–A conjugated polymer with dppz as an acceptor and proved the great potential of constructing ternary memory devices using the dppz structure.