Search

Local laser‐induced oxidation is an extremely valuable technique to perform high‐throughput optimization across multidimensional parameter sets. In this work, a versatile method is presented for the synthesis of titanium dioxide (TiO2) thin‐films with varying crystalline structures through the use of localized, visible, continuous‐wave laser‐processing. By controlling the laser intensity and the exposure time, the conversion of amorphous titanium disulfide (a‐TiS2) precursor films into distinct phases of TiO2 is achieved and a laser‐induced oxidation phase diagram is constructed with the resulting material phases, including anatase, rutile, and black TiO2. By utilizing the dependence of phase formation on the rate and duration of laser energy input, mixtures of anatase and rutile phases are fabricated with controlled spatial arrangements. Photocatalytic properties of the synthesized films are evaluated using the degradation of nitrogen oxide (NOx) gas under UV illumination and an organic dye under white‐light illumination, revealing that mixtures of anatase and rutile phases demonstrate superior photocatalytic activity. The laser‐induced oxidation method highlighted showcases a strategy for precisely tailored phase composition for directly tunable properties, paving the way for in‐depth studies into structure‐property relationships in photocatalysis and other applications of metal oxide films. [ABSTRACT FROM AUTHOR]

Flexible and transparent pressure sensor arrays can find applications in many places such as touch panels, artificial skin, or human motion detection. However, conventional strain gauges are rigid and opaque and are not suitable for such applications. Graphene-based percolative strain gauges can overcome these challenges but currently are still in the infancy of their development. In this work, the performance of graphene-based percolative strain gauges is investigated and guidelines to improve the durability and sensitivity of graphene films as sensing elements are developed. It is found that the gauge factor depends on the initial resistance of the graphene film. For the same film resistance, it is found that graphene flake size and film morphology also play a role in determining the gauge factor. Increasing the flake-flake resistance through assembly of surfactant molecules between graphene flakes provides an additional route to enhance the gauge factor. Furthermore, encapsulating the percolative film in micrometer-thin Poly(methyl methacrylate) does not disrupt the sensing process but significantly improves the sensor's durability. Finally, thus enhanced graphene strain gauges are integrated into flexible and transparent pressure sensor arrays that exhibit high reproducibility and sensitivity. [ABSTRACT FROM AUTHOR]

Here we report on the fabrication and characterizationof a noveltype of strain gauge based on percolative networks of 2D materials.The high sensitivity of the percolative carrier transport to straininduced morphology changes was exploited in strain sensors that canbe produced from a wide variety of materials. Highly reliable andsensitive graphene-based thin film strain gauges were produced fromsolution processed graphene flakes by spray deposition. Control ofthe gauge sensitivity could be exerted through deposition-inducedchanges to the film morphology. This exceptional property was explainedthrough modeling of the strain induced changes to the flake–flakeoverlap for different percolation networks. The ability to directlydeposit strain gauges on complex-shaped and transparent surfaces waspresented. The demonstrated scalable fabrication, superior sensitivityover conventional sensors, and unique properties of the describedstrain gauges have the potential to improve existing technology andopen up new fields of applications for strain sensors. [ABSTRACT FROM AUTHOR]