Elevating the resistive memory from binary to ternary by introducing trialkyl phosphorus into binaphthol/ferrocene cores in their polystyrene composites

The design of electrically active composites by modifying with functional groups with definite switching mechanism is the key to develop new multi-level memorizers. In this work, five binaphthol and two ferrocene derivants were embedded into polystyrene (PS) to fabricate FTO/binaphthol or ferrocene derivants@PS/Ag memory devices. Binaphthol derivants were firstly used in the memory devices, four of which exhibit binary resistive switching performance with ON/OFF ratio about 102.02-102.44. Interestingly, the trialkyl phosphorus -bearing one demonstrates excellent ternary memory performance with considerable ON2/ON1/OFF current ratio of 102.30:104.22:1, relatively low set voltages (0.99 and 1.68 V), good reliability, and high ternary yield of 66 %. Besides, two trialkyl phosphorus-containing ferrocene@PS composites also illustrate typical ternary resistive switching behavior with ON2/ON1/OFF current ratio of 102.34:103.78:1 and 101.97:104.47:1. Their ON1 states stem the increased dihedral angle of two naphthaline rings with the injection of hot carriers (for binaphthol derivants) and oxidation of ferrocene units (for ferrocene derivants). Interestingly, the ON2 states root from the flattening of tricoordinate phosphorus, which can enhance the conjugated degree, and as a result, higher conductivities. The rigid PS matrix can act as charge blocking layer and aggregation-inhibited species. The introduction of trialkyl phosphorus will be an efficient strategy for implementing low cost organic multi-level memorizer.

Automated summary

The design of electrically active composites by modifying with functional groups with definite switching mechanism is crucial for developing new multi-level memorizers. This study embedded different binaphthol and ferrocene derivants into polystyrene (PS) to fabricate memory devices with excellent binary and ternary resistive switching performance. The introduction of trialkyl phosphorus is proposed as an efficient strategy for implementing low cost organic multi-level memorizer.