The advancement of Internet of Things has stimulated huge demands on low-voltage flexible electronics. Carbon-nanotube (CNT)-based electronics are of great promise to this end for their intrinsic flexibility, high carrier mobility, and capability to synthesize as semiconducting or metallic to serve as the channels, electrodes, and interconnects of circuits. However, the gate dielectric often has to adopt brittle oxides, which can seriously limit the device flexibility. Herein, we show that a hybrid polyimide-Al2O3 material can serve as a good gate dielectric to realize truly intrinsic flexibility of transistors and circuits based on CNTs. With this hybrid dielectric, high-performance all-CNT transistors and integrated circuits of inverters, ring oscillators, and logic gates are demonstrated. Particularly, the inverters exhibit a remarkably high gain of 342.5 and can be used as an analog amplifier for millivolt small signals. Ultralow voltage (50 mV) operation is also feasible, which highlights the great promise for low-power applications.

Flexible tribovoltaic direct-current (DC) generators are urgently expected by wearable applications. Traditional rigid contact-separation type tribovoltaic DC generators normally have non-ignorable friction loss and cannot sustain outstanding outputs. This hinders their serviceability in continuous motion scenarios. Here, flexible liquid-based DC generators (FLGs) with metalliquid-semiconductor indium gallium zinc oxide (IGZO) stack structures are reported. The FLG with Pt/H 2 O/IGZO structure delivers a peak short-circuit current density up to 2.3 µA cm −2 , a peak open-circuit voltage up to 620 mV, and a power density up to 0.1 µW cm −2 . The differences in the properties of different liquid-solid interfaces are studied by density functional theory, showing that the bond formation, charge-transfer-induced dipole electric field at the solid-liquid interface, and the built-in electric field are responsible for the generation and separation of electron-hole pairs to form continuous DC. The proposed FLG can keep excellent performance even after >5 × 10 4 shaking cycles or exposing to ambient conditions for 30 days, showing extraordinary stability. Besides charging capacitors or driving LEDs, the FLG is further demonstrated to work for self-powered multifunctional sensing, enabling pressure, position-posture, or temperature detections. This design offers potential solutions and novel possibilities for next-generation self-powered wearable electronics.

Organic light-emitting diodes (OLEDs) are widely used in full-color display panels, fluorescent tubes and solid-state lighting devices. In recent years, due to the material utilization yield of the vacuum deposition method is very low and maintaining a high vacuum further increases the fabrication cost and complexity, solution processing method has become a research hotspot. However, the development of solution-processed OLEDs has a great challenge in multilayer structure formation and nearly all prior reports on solution-processed OLEDs were utilizing a vacuum deposited electron-transport layer (ETL). Therefore, it is of great significance to further research on all solution-processed OLEDs whose ETL were spin-coated. In this paper, spin-coated ETL based OLED with high current efficiency that comparable with vacuum deposited ETL based OLED were successfully achieved.

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