Random styrenic copolymers with pendant pyrene moieties: Synthesis and applications in organic field-effect transistor memory

Three random copolymers comprised pendant styrene and 4-(1-pyrenyl)-styrene (PyS) moieties in different molar ratios (21.4:1 (P1), 3.9:1 (P2), and 1.4:1 (P3)) were synthesized and employed as charge storage polymeric electret for nonvolatile organic field-effect transistor (OFET) memory application. The impact of varying the molar ratio in side-chain electron-donating pyrene moieties on the thermal, optical, photophysical, electrochemical, and electrical properties of the resulting pendant copolymers was evaluated to establish structure-property relationship. The OFET memory with P3 electret layer exhibits a largest memory window of 41.8 V, long retention time of 10⁴ s with memory ratio of 10⁵, and stable reversibility of at least 100 cycles due to enhanced field-induced holes trapping ability from higher PyS composition ratio. Therefore, polymer electret with pendant functional moieties shows potential for use as trapping layer in OFET memory devices.