By the current processing technology, it is a challenge to obtain ultrahigh-density information storage in the conventional binary floating-gate-based organic field-effect transistor (FG-OFET) nonvolatile memories (NVMs). To develop a multilevel memory in one cell is a feasible solution. In this work, we demonstrate FG-OFET NVMs with an integrated polymer floating-gate/tunneling (I-FG/T) layer consisting of poly(9,9dioctylfluorene-co-benzothiadiazole) (F8BT) and polystyrene. The photoelectric effect of organic/polymer semiconductors is used to improve the controllability of the polarity and the number of the charges stored in the floating-gate. The FG-OFET NVMs integrate light sensitivity and nonvolatile information storage functions. By selecting suitable optical and electrical programming/erasing conditions, three-level information storage states, corresponding to electron storage, approximate neutrality, and hole storage in the floating-gate, are achieved and freely switched to each other. The memory mechanism and the dependence of the memory performances on the F8BT contents in I-FG/T layers are investigated. As a result, good memory performances, with mobility larger than 1.0 cm 2 V −1 s −1 , reliable three-level switching endurance over 100 cycles, and stable three-level retention capability over 20 000 s, are achieved in our memory. Furthermore, an imaging system with a nonvolatile information storage function is demonstrated in a 16 × 5 array of FG-OFET NVMs.

Organic field‐effect transistor‐ (OFET‐) based nonvolatile memories (NVMs) are becoming more important as a core component in flexible and wearable electronics. New polymer materials containing abundant hydroxyl groups are synthesized and employed as the functional gate dielectric for OFET‐NVM devices. The dependence of the memory performances on the hydroxyl content of the polymers is investigated. A variety of gate dielectric structures are proposed to verify that the memory mechanism originates from the reversible remnant polarization of hydroxyl groups in the polymers and to improve the retention capability of the OFET‐NVM devices by preventing the charge trapping in the polymers at the reading state. As a result, good memory performance is achieved with a large memory window of 33.7 V and memory on/off ratio of 1.1 × 104 on average, long retention properties with clearly distinguishable binary states over 10 000 s, and reliable writing/erasing switching endurance over 200 cycles in the optimal OFET‐NVM device, in which the polymer with the most hydroxyl content is sandwiched by two insulator films. Good strategies for the design of the polarizable polymers as the functional gate dielectrics and for improvement of OFET‐NVM device performance are demonstrated.

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.

Ferroelectric organic field-effect transistor nonvolatile memories (Fe-OFET-NVMs) offer attractive features for future memory applications, such as flexible and wearable electronics. Polymer semiconductor-based top-gate Fe-OFET-NVMs possess natural advantages in the device structure and processing manufacturing, compared to small-molecule semiconductor-based bottom-gate Fe-OFET-NVMs. However, their performances, such as mobility and operating voltages, should be further improved to be comparable to those of the latter. In this Letter, we develop a route to achieve high-performance top-gate Fe-OFET-NVMs, by employing a polymer semiconductor channel and self-organized ferroelectric/dielectric gate insulators, which were processed by a solution spin-coating technique. The optimal Fe-OFET-NVM exhibits a high mobility of 1.96 cm2/V s on average, a reliable endurance over 400 cycles, a stable retention capability over 6 × 104 s, and a life more than one year. Furthermore, the operating voltage of the Fe-OFET-NVM is reduced to ±20 V by scaling down the thickness of the ferroelectric/dielectric gate insulator. The whole performances of our memories are comparable to or better than those of the previous Fe-OFET-NVMs.

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