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Source-semiconductor-drain coplanar transistors with an organic semiconductor layer located within the same plane of source/drain electrodes are attractive for next-generation electronics, because they could be used to reduce material consumption, minimize parasitic leakage current, avoid cross-talk among different devices, and simplify the fabrication process of circuits. Here, a one-step, drop-casting-like printing method to realize a coplanar transistor using a model semiconductor/insulator [poly(3-hexylthiophene) (P3HT)/polystyrene (PS)] blend is developed. By manipulating the solution dewetting dynamics on the metal electrode and SiO dielectric, the solution within the channel region is selectively confined, and thus make the top surface of source/drain electrodes completely free of polymers. Subsequently, during solvent evaporation, vertical phase separation between P3HT and PS leads to a semiconductor-insulator bilayer structure, contributing to an improved transistor performance. Moreover, this coplanar transistor with semiconductor-insulator bilayer structure is an ideal system for injecting charges into the insulator via gate-stress, and the thus-formed PS electret layer acts as a "nonuniform floating gate" to tune the threshold voltage and effective mobility of the transistors. Effective field-effect mobility higher than 1 cm V s with an on/off ratio > 10 is realized, and the performances are comparable to those of commercial amorphous silicon transistors. This coplanar transistor simplifies the fabrication process of corresponding circuits.

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The emerging applications of organic field-effect transistors (OFETs), such as photon memories and artificial synapses, require polymer dielectrics with superior charge trapping properties. Despite the introduction of high-k and fluorinated polymers in the performance optimization of OFETs, there is still a lack of widely recognized acknowledgment between molecular structures and charge trapping characteristics, as well as no general principles in designing polymeric dielectrics for electronic memory devices. Here, we propose a series of fluorinated polystyrene isomers through side-chain engineering, namely, ortho-(o-), meta-(m-), and para-fluorinated polystyrene (p-FPS). The gradually enlarged intramolecular charge separation of o-, m-, and p-FPS enhances molecular electrostatic potential, which promotes polarization and charge trapping performances, resulting in an enlarged dielectric constant, as well as more deep traps toward stable electret. Subsequently, largely improved photon memory and artificial synapse performances of p-FPS-based OFETs further suggest the dominating role of dielectric side-chain structures on memory and synapse performances, leading to a recommendation of low-k (ε r < 5) dielectric polymers with enhanced electrostatic potential for OFET-based memory devices and bionic nervous systems.

Poly‐β‐hydroxybutyrate (PHB) is microbial carbon and energy storage polymer, which can be degraded into water‐soluble β‐hydroxybutyric acid in the gastrointestinal tract of aquatic animals. A 60‐day culture experiment was performed using Chinese mitten crab, Eriocheir sinensis (Milne‐Edwards) juveniles with an average initial body weight of 0.74 ± 0.06 g which were fed a diet supplemented with 0%, 0.5%, 1%, 3% or 5% PHB. A PHB dietary supplementation of 1% and 3% significantly improved the body weight gain, moulting frequency and concomitantly reduced 2nd–3rd moulting intervals of the crabs (P < 0.05). The dietary PHB level positively related to hepatopancreatic pepsin, trypsin and lipase activity (P < 0.05). Increasing the dietary PHB also improved total superoxide dismutase activity, but reduced alkaline phosphatase and acid phosphatase activity in the serum of hemolymph (P < 0.05). A 16S rRNA gene analysis by denaturing gradient gel electrophoresis indicated that PHB supplementation led to a significantly higher range‐weighted richness, diversity and evenness of the gut bacterial community when dosed at 3% in the feed. The beneficial effects of PHB are discussed in terms of immune defense, metabolism and gut microbiota of the crabs.