Simple solvent‐vapor annealing was used to fabricate single crystals of dioctylbenzothienobenzothiophene on a polymer dielectric surface. By involving self‐organized phase separation, crystal length is enhanced and a good semiconductor/insulator interface is obtained. The field‐effect transistors (FETs) exhibit an average p‐type FET mobility of 3.0 cm2 V−1 s−1, with a highest value of 9.1 cm2 V−1 s−1. The FET mobility increases as temperature decreases, which suggests intrinsic bandlike transport.

Intercalation and deintercalation of lithium ions at electrode surfaces are central to the operation of lithium-ion batteries. Yet, on the most important composite cathode surfaces, this is a rather complex process involving spatially heterogeneous reactions that have proved difficult to resolve with existing techniques. Here we report a scanning electrochemical cell microscope based approach to define a mobile electrochemical cell that is used to quantitatively visualize electrochemical phenomena at the battery cathode material LiFePO 4 , with resolution of B100 nm. The technique measures electrode topography and different electrochemical properties simultaneously, and the information can be combined with complementary microscopic techniques to reveal new perspectives on structure and activity. These electrodes exhibit highly spatially heterogeneous electrochemistry at the nanoscale, both within secondary particles and at individual primary nanoparticles, which is highly dependent on the local structure and composition.

High‐resolution scanning electrochemical cell microscopy (SECCM) is used to image and quantitatively analyze the hydrogen evolution reaction (HER) catalytically active sites of 1H‐MoS2 nanosheets, MoS2, and WS2 heteronanosheets. Using a 20 nm radius nanopipette and hopping mode scanning, the resolution of SECCM was beyond the optical microscopy limit and visualized a small triangular MoS2 nanosheet with a side length of ca. 130 nm. The electrochemical cell provides local cyclic voltammograms with a nanoscale spatial resolution for visualizing HER active sites as electrochemical images. The HER activity difference of edge, terrace, and heterojunction of MoS2 and WS2 were revealed. The SECCM imaging directly visualized the relationship of HER activity and number of MoS2 nanosheet layers and unveiled the heterogeneous aging state of MoS2 nanosheets. SECCM can be used for improving local HER activities by producing sulfur vacancies using electrochemical reaction at the selected region.

In this paper, we report the surprisingly low electrolyte/electrode interface resistance of 8.6 Ω cm(2) observed in thin-film batteries. This value is an order of magnitude smaller than that presented in previous reports on all-solid-state lithium batteries. The value is also smaller than that found in a liquid electrolyte-based batteries. The low interface resistance indicates that the negative space-charge layer effects at the Li3PO(4-x)N(x)/LiCoO2 interface are negligible and demonstrates that it is possible to fabricate all-solid state batteries with faster charging/discharging properties.

We developed a simple and novel method to fabricate complementary-like logic inverters based on ambipolar graphene field-effect transistors (FETs). We found that the top gate stacks (with both the metal and oxide layers) can be simply prepared with only one-step deposition process and show high capacitive efficiency. By employing such a top gate as the operating terminal, the operating bias can be lowered within 2 V. In addition, the complementary p- and n-type FET pairs can be also simply fulfilled through potential superposition effect from the drain bias. The inverters can be operated, with up to 4-7 voltage gains, in both the first and third quadrants due to the ambipolarity of graphene FETs. For the first time, a match between the input and output voltages is achieved in graphene logic devices, indicating the potential in direct cascading of multiple devices for future nanoelectronic applications.

Carbon‐based metal‐free catalysts for the hydrogen evolution reaction (HER) are essential for the development of a sustainable hydrogen society. Identification of the active sites in heterogeneous catalysis is key for the rational design of low‐cost and efficient catalysts. Here, by fabricating holey graphene with chemically dopants, the atomic‐level mechanism for accelerating HER by chemical dopants is unveiled, through elemental mapping with atomistic characterizations, scanning electrochemical cell microscopy (SECCM), and density functional theory (DFT) calculations. It is found that the synergetic effects of two important factors—edge structure of graphene and nitrogen/phosphorous codoping—enhance HER activity. SECCM evidences that graphene edges with chemical dopants are electrochemically very active. Indeed, DFT calculation suggests that the pyridinic nitrogen atom could be the catalytically active sites. The HER activity is enhanced due to phosphorus dopants, because phosphorus dopants promote the charge accumulations on the catalytically active nitrogen atoms. These findings pave a path for engineering the edge structure of graphene in graphene‐based catalysts.

A facile solution process for the fabrication of organic single crystal semiconductor devices which meets the demand for low-cost and large-area fabrication of high performance electronic devices is demonstrated. In this paper, we develop a bottom-up method which enables direct formation of organic semiconductor single crystals at selected locations with desired orientations. Here oriented growth of one-dimensional organic crystals is achieved by using self-assembly of organic molecules as the driving force to align these crystals in patterned regions. Based upon the self-organized organic single crystals, we fabricate organic field effect transistor arrays which exhibit an average field-effect mobility of 1.1 cm2V−1s−1. This method can be carried out under ambient atmosphere at room temperature, thus particularly promising for production of future plastic electronics.

We report single crystal formation of organic semiconducting small molecules via solvent vapor annealing (SVA) on a polymer base film (PBF). The soluble PBF strongly assists the self-assembly of small molecules to form single crystals; this sharply contrasts typical SVA where the inorganic base film such as SiO 2 plays little or no role. We use a matrix of organic solvents and polymers to systematically investigate the re-crystallization of dioctylbenzothienobenzothiophene (C8-BTBT) by SVA on polymer surfaces. Crystallization by SVA clearly correlates with the miscibility of solvents and PBFs. The PBF dramatically increases the amount of condensed solvent on the surface. The additional solvent enhances the molecular mobility of small molecules to allow self-assembly in a distance over hundreds of microns, and stimulates crystal growth via Ostwald ripening. Based on this mechanism, the final crystal size of small molecules can be controlled to vary from tens of microns to millimetres simply by modifying the thickness of the base film. The approach was successfully applied to several semiconducting small molecules to form single crystals that exhibited field-effect response. Hence SVA on PBF is presented as a general and promising method for the direct fabrication of organic single crystals on polymer dielectrics.