Confined Synthesis of 2D Nanostructured Materials toward Electrocatalysis

The transfer process is crucial for obtaining high-quality graphene for its large-scale industrial application. In this review, graphene transfer methods are systematically classified along with an analysis of the contamination or impurity of graphene that is introduced during the transfer process. Two key processes are emphasized, the substrate removal process and the direct/indirect transfer of graphene. Based on the efficiency and cost factors of industrial scale production, various transfer methods are summarized and evaluated. Potential transfer technologies and future research directions for industrial application are prospected.

Towards large-scale graphene transfer

Cerium-doped indium oxide transparent electrode for semi-transparent perovskite and perovskite/silicon tandem solar cells

Attenuated tactile sensation may occur on people who have skin trauma or prolonged glove usage. Such decreased sensation may cause patients to become less responsive to minute skin deformations and consequently fail to regulate their limbs properly. To mitigate such health conditions, an integrated tactile enhancement system that exceeds the human skin's sensitivity is indispensable for patients to regain the touch sensation of minute deformations. Here, we develop a visually aided tactile enhancement system for precise motion control by combining ultrathin, highly sensitive, crack-based strain sensors and signal acquisition circuit with real-time display equipment. By optimizing the thicknesses of the substrates and sensitive films of the strain sensors, our device has a detection limit as low as 0.01% and an ultrahigh gauge factor of 44 013 at a strain of 0.88%, which exceeds the performance of previous devices with crack-based strain sensors within minute strain range. The high sensitivity of the ultrathin crack-based strain sensor makes it possible for our visually aided tactile enhancement system to detect tiny deformations such as the slight brush of a feather, the fall of water droplets on fingers, and even the touch of invisible wires. Our study demonstrates promising applications of integrated visually aided tactile enhancement systems in human-machine interactions and artificial intelligence.

Visually aided tactile enhancement system based on ultrathin highly sensitive crack-based strain sensors

This work reports an analytical method for determining electrical resistivity (ρ) and sheet resistance (RS) of isotropic conductors. The method is compared with previous numerical solutions and available experimental data showing a universal behavior for isotropic conductors. An approximated solution is also reported allowing one to easily determine ρ and RS for samples either with regular or arbitrary shapes.

/pdf/simple-analytical-method-for-determining-electrical-2qhiob3s3i.pdf

Simple analytical method for determining electrical resistivity and sheet resistance using the van der Pauw procedure.

Expected for many promising applications in the field of electronics and optoelectronics, a reliable method for the characterization of graphene electrical transport properties is desired to predict its device performance or provide feedback for its synthesis. However, the commonly used methods of extracting carrier mobility from graphene field effect transistor or Hall-bar is time consuming, expensive, and significantly affected by the device fabrication process other than graphene itself. Here we reported a general and simple method to evaluate the electrical transport performance of graphene by the van der Pauw–Hall measurement. By annealing graphene in vacuum to remove the adsorbed dopants and then exposing it in ambient surroundings, carrier mobility as a function of density can be measured with the increase of carrier density due to the dopant re-adsorption from the surroundings. Further, the relationship between the carrier mobility and density can be simply fitted with a power equation to the first level approximation, with which any pair of measured carrier mobility and density can be normalized to an arbitrary carrier density for comparison. We experimentally demonstrated the reliability of the method, which is much simpler than making devices and may promote the standard making for graphene characterization.

Shu Yang

Papers

A general and simple method for evaluating the electrical transport performance of graphene by the van der Pauw-Hall measurement