Organic field-effect transistors (OFETs) as nonvolatile memory units are essential for lightweight and flexible electronics, yet the practical application remains a great challenge. The positively charged defects in pentacene film at the interface between pentacene and polymer caused by environmental conditions, as revealed by theoretical and experimental research works, result in unacceptable high programming/erasing (P/E) gate voltages in pentacene OFETs with polymer charge-trapping dielectric. Here, we report a pentacene OFET in which an n-type semiconductor layer was intercalated between a polymer and a blocking insulator. In this structure, the hole barrier caused by the defect layer can be adjusted by the thickness and charge-carrier density of the n-type semiconductor interlayer based on the electrostatic induction theory. This idea was implemented in an OFET structure Cu/pentacene/poly(2-vinyl naphthalene) (PVN)/ZnO/SiO 2 /Si(p + ), which shows low P/E gate voltages, large field-effect mobility (0.73 cm 2 V −1 s −1 ), fast P/E speeds (responding to a pulse width of 5 × 10 −4 s), and long retention time in air.

Organic field-effect transistor (OFET) memory based on pentacene has attracted a lot of attentions due to its promising prospect of application in flexible electronics, while the high programming/erasing (P/E) gate voltages due to the existence of hole barrier at pentacene/polymer interface leaves great challenges for its commercial applications. A high-performance pentacenebased OFET nonvolatile memory (ONVM) with polymer blends is reported here as the charge-trapping layer containing poly(2-vinyl naphthalene) (PVN) and poly{[N,N'-bis(2-octyldodecyl)naphthalene-1,4,5,8-bis(dicarboximide)-2,6diyl]-alt-5,5'-(2,2'-bithiophene)} (N2200). The presence of N2200, an n-type semiconductor, in blends significantly improves the memory performance of pentacene-based memory devices based on the static-electric effect. The electrons in N2200 are aggregated near the pentacene/polymer interface due to the electric attraction from the positively charged defects in pentacene. Furthermore, those electrons reduce the height of hole barrier and produce local easy-transportation paths for holes between pentacene and PVN, which enables the electret-based ONVM device with low P/E voltages, fast P/E speeds, large mobility and stable multilevel data-storage ability in ambient air.

Organic field-effect transistors (OFETs) with polymer charge-trapping dielectric, which exhibit many advantages over Si-based memory devices such as low cost, light weight, and flexibility, still suffer challenges in practical application due to the unsatisfied endurance characteristics and even the lack of fundamental of behind mechanism. Here, we revealed that the degradation of endurance characteristics of pentacene OFET with poly(2-vinyl naphthalene) (PVN) as charge-storage layer is dominated by the deep hole-traps in PVN by using the photo-stimulated charge de-trapping technique with the fiber-coupled monochromatic-light probes. The depth distribution of hole-traps in PVN film of pentacene OFET is also provided.

Flexible organic field-effect transistor nonvolatile memories (OFET-NVMs) with polymer electrets have aroused great attention for its important role in next-generation flexible data storage devices application. However, the OFET-NVMs to date still hardly reach the requirements for practical applications. In air environment, the positively charged defects formed in pentacene near the interface with polymer, result in unsatisfied high programming/erasing (P/E) voltages. Here, we propose an OFET memory structure, in which an n-type semiconductor N, N’-Bis(3-pentyl) perylene-3, 4, 9, 10-bis(dicarboximide) (PTCDI-C13) is inserted between pentacene and poly(4-vinyl phenol (PVN). Based on the electrostatic induction effect, electrons are induced on the surface of PTCDI-C13 due to the electrostatic field generated by the positive charges at the interface of pentacene/polymer, and compensate part of the positive charges at the interface, resulting in the reduction of the height of hole-barrier. The flexible memory device with PTCDI-C13 exhibits a memory window of larger than 7 V at low P/E voltages (±20 V), fast switching speeds (0.5 ms), good P/E endurance (> 400 cycles), large field-effect mobility (0.026 cm2·V-1·s-1), and long retention time (over 104 s).