High-response organic thin-film memory transistors based on dipole-functional polymer electret layers

A molecular design for the electret material of n-operating organic field-effect transistor-based (OFET) memories is introduced. A large memory window and high operating speed were achieved while the polar groups are connected to the polymer chain of polyimide, which plays the role of electret of a transistor memory device. The phase variation of electrical force microscopy images showed that polarization field induces charge trapping states on the surface of electret layer and accumulates charged carriers within the conducting channel of OFET to achieve high-performance memory and transistor simultaneously. An extra-large memory window was also obtained by introducing photo-induced charge transfer effect.