No abstract

Direct light‐to‐work conversion enables manipulating remote devices in a contactless, controllable, and continuous manner. Although some pioneering works have already proven the feasibility of controlling devices through light‐irradiation‐induced surface tension gradients, challenges remain, including the flexible integration of efficient photothermal materials, multifunctional structure design, and fluidic drag reduction. This paper reports a facile one‐step method for preparing light‐driven floating devices with functional surfaces for both light absorption and drag reduction. The direct laser writing technique is employed for both arbitrary patterning and surface modification. By integrating the functional layer at the desired position or by designing asymmetric structures, three typical light‐driven floating devices with fast linear or rotational motions are demonstrated. Furthermore, these devices can be driven by a variety of light sources including sunlight, a filament lamp, or laser beams. The approach provides a simple, green, and cost‐effective strategy for building functional floating devices and smart light‐driven actuators.

Doping an organic crystal such as an inorganic semiconductor without having a bad influence on crystalline quality is a very difficult task because weak intermolecular interactions and lattice mismatches exist in organic condensed states. We report here the successful growth of tetracene and pentacene-doped trans-1,4-distyrylbenzene (trans-DSB) crystals with high crystalline quality, large size, and excellent optical properties. The doped concentration up to 10% can be achieved by controlling the temperature of the crystal growth zone. The first key point for the crystals with a high doping ratio is the choice of the host (trans-DSB) and guest (tetracene or pentacene) molecules with comparable crystal lattice structures, which ensure less lattice mismatch. The second key point is crystal growth at relative high temperatures by the physical vapor transport (PVT) method, which gives the guest molecules high kinetic energy to incorporate into the crystal lattice of the host. These doped crystals with slice shape and large size (millimeter scale) maintain ordered layer structures and crystal surface continuities, which are verified by X-ray diffraction (XRD) and atomic force microscopy (AFM) analysis. Efficient energy transfer from the host to the guest and the suppressing of the interaction among the guest molecules lead to color-tunable emission and high luminescent efficiencies (blue for undoped trans-DSB, η = 65 ( 4%; green for tetracene-doped trans-DSB, η = 74 ( 4%; red for pentacenedoped trans-DSB, η = 28 ( 4%). Steady-state and time-resolved fluorescence spectroscopy of undoped and doped crystals, and their amplified spontaneous emissions, have been investigated. These doped crystals are expected to be of interest for lightemitting transistors, diodes, and electrically pumped lasers.

Silver microflower arrays constructed by upright nanoplates and attached nanoparticles were fabricated inside a microfluidic channel, thus a robust catalytic microreactor for allowing in situ SERS monitoring was proposed. On-chip catalytic reduction shows that the silver microflowers have high catalytic activity and SERS enhancement.