Study of the pyridyl-containing charge-trapping functional materials in the organic field effect transistor memory devices

Abstract

Interface materials can effectively improve the storage characteristics of the memory devices. In this paper, a series of functional materials with propyl chain bridging pyridyl ring and triethoxysilyl group, 3-(3-(triethoxysilyl)propyl)pyridine (Pyridyl-C), N-(3-(triethoxysilyl)propyl)pyridin-3-amine (Pyridyl-N) and 3-(3-(triethoxysilyl)propoxy)pyridine (Pyridyl-O), were selected as the charge-storage interface materials to study the storage characteristics of nonvolatile organic field-effect transistor (OFET) memory devices. The results demonstrated that the memory performance could be enhanced by adding lone-pair-electron atoms (N, O) between pyridyl group and propyl chain. With the programming voltage of −30 V staying in dark condition for 1 s, the memory windows were increased from 12.48 V to 14.95 V, then to 21.99 V when the –O and N atoms were introduced, respectively. All memory devices could remain stable for more than 104 s. The morphology images indicated that there were aggregates on the interfacial layers, and the size was increased when the atoms (O, N) were added because of the hydrogen-bonding interaction. The aggregates can increase the contact area between pentacene and interface materials and further enlarge the effective tunneling area. In addition, the variation of self-assembling immersing time for preparing Pyridyl-N layers was studied, indicating that with the extension of the immersing time, the size of aggregates was increasingly enlarged and memory performance was improved correspondingly.