High-performance flexible organic thin-film transistor nonvolatile memory based on molecular floating-gate and pn-heterojunction channel layer

Flexible floating-gate structural organic thin-film transistor (FG-OTFT) nonvolatile memories (NVMs) are demonstrated based on an integrated molecular floating-gate/tunneling (I-FG/T) layer and a pn-heterojunction channel layer. Semiconducting polymer poly(9,9-dioctylfluorene-co-benzothiadiazole) nanoparticles and insulating polymer polystyrene are used to build the I-FG/T layers by spin-coating their solution. The dependence of the memory performances on the structure of I-FG/T layers is researched. For achieving a large charge storage capacity, the pn-heterojunction channel, consisting of 2,9-didecyldinaphtho[2,3-b:2 ',3 '-f]thieno[3,2-b]thiophene and F16CuPc, is fabricated to provide both electrons and holes for injecting and trapping in the floating gate by overwriting the stored charges with an opposite polarity at the programming and erasing voltages, respectively. As an optimal result, a high performance flexible FG-OTFT NVM is achieved, with a large memory window of 21.6 V on average, a highly stable charge storage retention capability up to 10 years, and a highly reliable programming/erasing switching endurance over 200 cycles. The FG-OTFT NVM also exhibits an excellent mechanical bending durability with the memory performances maintaining well over 6000 bending cycles at a bending radius of 5.9 mm.