Uni- and Bidirectional Rotation and Speed Control in Chiral Photonic Micromotors Powered by Light.

Liquid crystalline polymers are attractive materials for untethered miniature soft robots. When they contain azo dyes, they acquire light-responsive actuation properties. However, the manipulation of such photoresponsive polymers at the micrometer scale remains largely unexplored.

Measurement of the amplitude and phase of the electrophoretic and electroosmotic mobility based on fast single-particle tracking.

The electrophoretic mobility of micron-scale particles is of crucial importance in applications related to pharmacy, electronic ink displays, printing, and food technology as well as in fundamental studies in these fields. Particle mobility measurements are often limited in accuracy because they are based on ensemble averages and because a correction for electroosmosis needs to be made based on a model. Single-particle approaches are better suited for examining polydisperse samples, but existing implementations either require multiple measurements to take the effect of electroosmosis into account or are limited in accuracy by short measurement times.

Waveguiding of Photoluminescence in a Layer of Semiconductor Nanoparticles.

Semiconductor nanoparticles (SNPs), such as quantum dots (QDs) and core/shell nanoparticles, have proven to be promising candidates for the development of next-generation technologies, including light-emitting diodes (LEDs), liquid crystal displays (LCDs) and solar concentrators. Typically, these applications use a sub-micrometer-thick film of SNPs to realize photoluminescence. However, our current knowledge on how this thin SNP layer affects the optical efficiency remains incomplete.

Dual Light and Temperature Responsive Micrometer-Sized Structural Color Actuators.

Externally induced color- and shape-changes in micrometer-sized objects are of great interest in novel application fields such as optofluidics and microrobotics. In this work, light and temperature responsive micrometer-sized structural color actuators based on cholesteric liquid-crystalline (CLC) polymer particles are presented. The particles are synthesized by suspension polymerization using a reactive CLC monomer mixture having a light responsive azobenzene dye.

Tunable top-down fabrication and functional surface coating of single-crystal titanium dioxide nanostructures and nanoparticles.

Titanium dioxide (TiO2) is a key component of diverse optical and electronic applications that exploit its exceptional material properties. In particular, the use of TiO2 in its single-crystalline phase can offer substantial advantages over its amorphous and polycrystalline phases for existing and yet-to-be-developed applications. However, the implementation of single-crystal TiO2 has been hampered by challenges in its fabrication and subsequent surface functionalization.